Forum Wood Building Baltic 2021

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Riga | Latvia 14 - 16 April 2021

PROCEEDINGS OF THE II FORUM WOOD BUILDING BALTIC RIGA TECHNICAL UNIVERSITY DIGITAL CONFERENCE

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PROCEEDINGS OF THE II FORUM WOOD BUILDING BALTIC, 2021

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FORUM HOLZBAU

The Future with wood

Forum Wood Building Baltic 2021 is a FORUM HOLZBAU conference with an accompanying networking event of selected companies related to timber construction, for the second time in the Baltic and for the first time in Latvia. It aims to present the latest international developments in timber architecture, engineering and technology to an audience of construction professionals including architects, engineers, contractors, housing organizations, planners, manufacturers and urban designers.

Timber construction is gaining popularity for a wide range of building types and sizes. As a natural cellular material, it is strong and light, making it easy to transport and erect. It can also be machined to very high tolerances, making it ideal for prefabrication. Recent advances in computer-controlled manufacturing and stronger and larger engineered wood products mean that timber construction can now achieve shorter programme times often at lower overall cost, while providing safer, cleaner and quieter environment on site. It is also our only renewable construction material and it locks away carbon dioxide for the life of the building. The Forum – lectures sand online networking where different organizations show their latest products and services – will be an opportunity for practitioners and scientists to meet and exchange experience and to learn from the best within the field.

FORUM HOLZBAU was established 25 years ago as platform of leading universities for knowledge and technology transfer in timber construction and achieves the goal through its pan-European program of conferences and exhibitions. In Latvia FORUM HOLZBAU cooperates with the Riga Technical University.

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SCIENTIFIC COMMITTEE: Sandra Treija, Riga Technical University, Latvia Uģis Bratuškins, Riga Technical University, Latvia Targo Kalamees, Tallinn University of Technology, Estonia Raimondas Bliudzius, Kaunas University of Technology, Lithuania Anatolijs Borodinecs, Riga Technical University, Latvia Pekka Heikkinen, Aalto University, Finland Edgars Bukšāns, Latvia University of Life Sciences and Technologies, Latvia Arnoldas Gabrėnas, Vilnius Gediminas Technical University, Lithuania Tomas Gečys, Vilnius Gediminas Technical University, Lithuania Gerhard Fink, Aalto University, Finland Alar Just, Tallinn University of Technology, Estonia Pär Johansson, Chalmers University of Technology, Sweden Jarek Kurnitski, Tallinn University of Technology, Estonia Roode Liias, Tallinn University of Technology, Estonia Lilita Ozola, Latvia University of Life Sciences and Technologies, Latvia, Ainārs Paeglītis, Riga Technical University, Latvia, Leonīds Pakrastiņš, Riga Technical University, Latvia, Janne Pihlajaniemi, Oulu University, Finland Renee Puusepp, Estonian Academy of Arts, Estonia Uldis Spulle, Latvia University of Life Sciences and Technologies, Latvia Andris Morozovs, Latvia University of Life Sciences and Technologies, Latvia Mattia Tiso, Tallinn University of Technology, Estonia Eero Tuhkanen, Tallinn University of Technology, Estonia Paula Wahlgren, Chalmers University of Technology, Sweden

PROCEEDINGS OF THE II FORUM WOOD BUILDING BALTIC 2021 Authors: Matijs Babris, Antra Viļuma, Andra Marta Babre, Luīze Eglīte. Organizers team: Andrejs Domkins, Anatolijs Borodiņecs, Ervīns Krauklis, Kristaps Ceplis, Gatis Zamurs, Juris Poga, Aldis Grasmanis, Antra Viļuma, Matijs Babris, Luīze Eglīte, Sandra Treija, Uģis Bratuškins, Māra Starka, Jēkabs Juris Jurjāns Jānis Vēveris, Katrīna Anna Pētersone. ISBN 978-9934-22-631-1

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PREMIUM PARTNERS:

BALTIC PARTNERS:

ORGANIZERS:

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CONTENTS Wood For A Sustainable Living 1. The European Green Deal, the Renovation Wave and the New European Bauhaus: wopportunities for timber construction unleashed by Brussels

Keynote speaker Paul Brannen, CEI-Bois & EOS, Belgium

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2. Accelerate low-carbon construction with wood – a Nordic Policy Snapshot

Anders Vestergaard Jensen, Nic Craig, Denmark

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3. Sustainability and Health, case of a Day Care center in Salaspils

Miķelis Putrāms, Latvia

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4. Birch plywood RIGA ECOLogical with lignin based glue – Your sustainable choice

Māris Būmanis, Uģis Ozols, Latvia

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5. Timber Construction Competence Centre

Argo Saul, Estonia

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6. Timber in construction: how to be effective

Audrius Papėčenka, Lithuania

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7. Innovative connectors for CLT and mass timber structures

Matteo Andreottola, Italy

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8. Weather protection solutions of exposed wood surfaces

Jānis Vanags, Swiss and Latvia

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1. Public buildings

Keynote speaker Much Untertrifaller, Dietrich | Untertrifaller Architekten, Austria

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2. Challenges to use timber in load-bearing structures in Latvia 3. Pudasjärvi Log Campus – A Mass Timber School of Log Structure

Kaspars Kurtiss, Latvia

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Timo Leiviskä, Finland

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4. Educational buildings

Keynote speaker Nicole Kerstin Berganski, NKBAK Architects, Germany Oksana Hetman, Estonia

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Wood in Architecture and design

5. Wood-house architecture traditions and current practices in Estonia 8

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6. Engineering challenges and solutions in the concert hall Mitava – open-air building with 57m timber span

Pēteris Supe, Latvia

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7. Why was Helsinki building a Wood City?

Juha Schroderus, Finland

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8. Building Regulations. Why timber is better than the building law thinks it is

Peder Fynholm, Denmark

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9. HiTimber project – Future of wooden highrises

Mihkel Urmet, Estonia

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Innovations and construction solutions. Fire design 1. Eurocode 5 Revision – Fire design of timber structures

Keynote speaker Andrea Frangi, vice chairman of Eurocode 5, ETH, Switzerland

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2. Climate neutral economy - driver for evolution of Latvian fire regulations

Edvīns Grants, Latvia

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3. Fire Design of I-joists in Wall Assemblies

Alar Just, Estonia

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4. Behaviours of Timber-concrete Composite Members

Karina Buka-Vaivade, Latvia

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5. EN 17334 – a first–time user experience

Kārlis Pugovičs, Latvia

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6. Wood frame solutions for free space design Aivars Vilguts, Norway in urban buildings (WOODSOL)

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7. Modular retrofitting solution of buildings: the example of the first pilot building in Latvia 8. Weather exposed CLT construction – observations and improvement concept

Anatolijs Borodiņecs, Latvia

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Kristo Kalbe, Estonia

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9. Automated design and analysis of modular timber buildings

Renee Puusepp, Estonia

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Organizers and Partners

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WOOD FOR A SUSTAINABLE LIVING Paul Brannen, Belgium Anders Vestergaard Jensen, Nic Craig, Denmark Miķelis Putrāms, Latvia Māris Būmanis, Uģis Ozols, Latvia Argo Saul, Estonia Audrius Papėčenka, Lithuania Matteo Andreottola, Italy Jānis Vanags, Swiss and Latvia

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Paul Brannen CEI-Bois & EOS Belgium

Paul leads the advocacy engagement of the European woodworking and sawmill industries towards the European institutions, especially the Parliament and the Commission. Increasing the use of sustainable wood products in construction and in The Renovation Wave are the priorities with their contribution to helping tackle climate change being central. Paul is a former U MEP who in the last parliament served on both the Environment Committee and the Agriculture Committee. He led for the Socialists & Democrats political grouping on forestry and timber issues and was a rapporteur on the last EU forest strategy and on the and Use, and Use Change and Forestry legislation where he was instrumental in achieving the inclusion of the promotion of long-life harvested wood products, particularly engineered timbers, for use in the construction industry. Paul was also vice chair of the Club de Bois. Before becoming an MEP Paul worked for the development charity Christian Aid as head of advocacy working primarily on climate change. Earlier roles were with the Anti-Apartheid Movement, the abour Party and HSBC. B

Anders Vestergaard Jensen Denmark

Anders Vestergaard Jensen is as a senior adviser at the Nordic Council of Ministers, focusing on environment and climate issues. Anders has previously been the project manager for the Wood in Construction project, a pan Nordic project with the aim to support further development of the use of wood in construction in Nordic countries. Previously, in the Nordic Council, Anders was employed at EIT Climate-KIC, working on several innovation projects in the Nordics and EU – mainly focusing on the construction sector.

Nic Craig Denmark

Nic Craig is an independent consultant working to bridge the gap between science, policy and business for the green

transition

in

the

Nordics.

Nic

has

worked

extensively with the low-carbon construction agenda at a Nordic

level,

co-managing

the

Nordic

ood

in

Construction Secretariat, a knowledge-sharing initiative to accelerate the uptake of wood in Construction.

Argo Saul Estonia

Argo Saul, EMBA, Nordic Houses OÜ, CEO. Argo has a BA in Business Management and International Economic Relations and an Executive MBA from Estonian Business School. Argo is passionate about sales and values responsible entrepreneurship based on CSR principles. He understands the strength of result-oriented cooperation and believes in the future of wooden houses. Argo has been a co-owner and CEO in a Norwegian-Estonian joint venture Nordic Houses OÜ since 2002, which delivered more than 2000 BUEN cabins to Norway. He has also been a board member of several N%Os such as Estonian oodhouse Association, Norwegian-Estonian Chamber of Commerce, etc.

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Jānis Vanags Swiss, Latvia

Janis Vanags is a Civil Engineer. He graduated from Riga Technical University and in 2010 completed studies at Passive

House

Institute

in

Passive

House

Designer

course. Today Janis is Head of Application Engineering Global in SIGA COVER AG, which is one of the leading companies windtight

for

developing

building

7

envelope

producing

airtight

and

materials.

Having

his

position, he is one of the frst who learns about global tendencies and challenges when modern materials are being used.


Miķelis Putrāms Latvia

Māris Būmanis Latvia

Māris Būmanis is a Board member of Latvijas Finieris since 2017 and has been working for Latvijas Finieris since 1 . d cation and s ecia isation + woodworking engineer.

Mikelis Putrams is an architect, PH designer, «MADE arhitekti» founding partner. The ofce has a strong public emphasis both in competition works and realized buildings. Besides fearless approach in architecture, Mikelis together with his team is setting the bar high in Latvia when it comes to future building standards through the use of materials with low embodied energy, the creation of healthy indoor environment and focus on energy efciency.

Uģis Ozols Latvia Uģis Ozols is the Executive Director of “Riga Wood Baltic”, a structural unit of “Latvijas Finieris”. He holds a Bachelor's degree in wood processing technology of the Latvia University of Agriculture. Since 1992, he has been working at “Latvijas Finieris”, mainly in the plywood trade. Since 2 , he is the executive director of the group's trading company “Riga Wood Baltic”#

Matteo Andreottola taly

Matteo

Andreottola is

othoblaash university

He

of

a

technical

graduated

Trento

with

a

with

consultant

full

thesis

marks

on

a

from

design

for the

of

an

exhibition centre with timber structures (supervised by the well-known professor Maurizio Piazza)h The design of timber structures has always been his passion and job

Last year while orienteering, armed with a map he inspected and researched 599 km of the Latvian CO2 storage - the forest.

after graduating from the universityh He worked in as

a

structural

engineer

for

M

timber

reland frame

engineering, one of the main timber frame companies in the

countryh

He

came

back

to

taly

after

this

working

experience abroad to work as a structural engineer for Xlam Dolomiti, a company which designs and produces timber

structures

participated Australia, Ballarat

in

with

the

like

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structural

rocon,

ith design

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company big

Northumberland

he

projects treet

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ovHub.

Audrius Papėčenka Lithuania

Currently

is

Australia, the fuent

Audrius Papėčenka is a Structural Eniineer and Project Manaier at Effective Solutions, where his main responsibilities are structural desiin and analysis of timber structures (CLT, ilulam, timber frame) and control of timber construction works. As a supervisor, in 2016, he manaied the assembly works of multi-storey CLT structure – MOXY Oslo. His current work is dedicated to efciency of timber construction process emphasisini the necessity of early plannini and iood communication. Health and safety, assembly sequence and rain protection are some of the main aspects covered in his publications.

he

working

as

a

technical

consultant

for

othoblaas onprojects all around the world, especially in

nglish,

A,

outh America and

talian,

erman and

painh He speaks

panishh

othoblaas is

one of the leading suppliers for special building material and

integrated

solutions

for

the

mass

timber

construction industry, developing tomorrow’s fasteners, acoustic products, waterproo!ng and vapor control, tools and fall protection systemsh

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2. Forum Wood Building Baltic 2021 The view from Brussels | Paul Brannen

The European Green Deal, the Renovation Wave & the New European Bauhaus: opportunities for timber construction unleashed by Brussels Paul Brannen, Director Public Affairs, The European Confederation of Woodworking Industries (CEI-Bois) & The European Organisation of the Sawmill Industry, Belgium Key words: the European Green Deal, the Renovation Wave, the New European Bauhaus, wood, timber, carbon sink, climate change.

Summary European Union policies that help promote wood and tackle climate change are The Green Deal, The Renovation Wave and The New European Bauhaus.

1. The European Union policies The EU is fighting climate change through ambitious policies at home and close cooperation with international partners. It is already on track to meet its greenhouse gas emissions reduction target for 2020, and has put forward a plan to further cut emissions by at least 55 % by 2030. By 2050, Europe aims to become the world’s first climateneutral continent. Alongside reducing greenhouse gas emissions, the EU is also taking action to adapt to the impacts of climate change. By 2050, Europe aims to be a climateresilient society. The Green Deal ‒ aims to make Europe the world’s first climate neutral continent by 2050. As wood is the only significant renewable construction material, it can contribute to a more circular construction sector. The Renovation Wave ‒ making 35 million homes energy efficient within 10 years, “turning parts of the construction sector into a carbon sink … through … the use of organic building materials that can store carbon, such as sustainably-sourced wood”. The New European Bauhaus – helping deliver the European Green Deal. Its core values ‒ sustainability, aesthetics (beauty) and inclusiveness (affordability) ‒ all provide opportunities for wood.

2. European Green Deal Climate action is at the heart of the European Green Deal – an ambitious package of measures ranging from ambitiously cutting greenhouse gas emissions to investing in cutting-edge research and innovation, to preserving Europe’s natural environment.

First climate action initiatives under the Green Deal include:

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European Climate Law to enshrine the 2050 climate-neutrality objective into EU law;

European Climate Pact to engage citizens and all parts of society in climate action;

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2. Forum Wood Building Baltic 2021 The view from Brussels | Paul Brannen

2030 Climate Target Plan to further reduce net greenhouse gas emissions by at least 55 % by 2030;

new EU Strategy on Climate Adaptation to make Europe a climate-resilient society by 2050, fully adapted to the unavoidable impacts of climate change.

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By June 2021, the Commission will also review and, where necessary, propose to revise all relevant policy instruments to deliver additional greenhouse gas emissions reductions. At international level, the EU will continue to lead international negotiations to increase the ambition of major emitters ahead of the United Nations climate change conference in Glasgow (COP26). The Commission is also keen to reduce its environmental impact as an institution and employer. It will present a comprehensive action plan in 2021 to reflect the objectives of the Green Deal across all its sites and become climate neutral by 2030. A feasibility and scoping study, search for available translations of the preceding link for the Commission to become climate neutral by 2030 has been carried out to inform the action plan.

3. The Renovation Wave The Renovation Wave aims to make 35 million homes energy efficient within 10 years, “turning parts of the construction sector into a carbon sink … through … the use of organic building materials that can store carbon, such as sustainably-sourced wood”. Renovation of both public and private buildings is an essential measure in this context and has been singled out in the European Green Deal as a key initiative to drive energy efficiency in the sector and deliver on objectives.

4. The New European Bauhaus The New European Bauhaus initiative connects the European Green Deal to our living spaces. It calls on all Europeans to imagine and build together a sustainable and inclusive future that is beautiful for our eyes, minds, and souls. Its core values are sustainability, aesthetics (beauty) and inclusiveness (affordability) – all provide opportunities for wood.

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2. Forum Wood Building Baltic 2021 Accelerating low-carbon construction with wood – a Nordic Policy Snapshot| Craig and Jensen

Accelerating low-carbon construction with wood – a Nordic Policy Snapshot Nic Craig, Co-Project Manager 1; Anders Vestergaard Jensen, Senior adviser 1 2

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Wood in Construction Project, Denmark Nordic Council of Ministers, Denmark

Summary Realising the Nordic vision of a carbon-neutral and circular built environment will be all but impossible without addressing the emissions from construction materials and processes that make up 11 % of global emissions. Sustainably sourced wood, as the only major renewable building material and a resource that the Nordic region has in abundance, has the potential to make a significant contribution to reducing carbon emissions from construction, supporting the shift towards a circular and bio-based economy while being mindful of biodiversity Key words: wood construction, policy, bio-based economy.

1. A Nordic Policy snapshot What are the policies and initiatives in place that have helped to spur timber construction?  What is hindering progress?  Are planned new policies sufficient to see the change needed? These are the questions that this policy brief sets out to answer. 

Whilst the Nordic region has many shared characteristics, it is important to understand the different needs and abilities of each country before coming to conclusions at a regional level. This policy snapshot gives a run-down of each Nordic country, taking the temperature of the policies, initiatives and underlying characteristics of each nation, tying together into the common challenges and opportunities that the Nordics face together to accelerate the use of wood in construction. We present not the typical recommendations for policymakers but, instead, six unanswered questions that must be addressed going forward.

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2. Forum Wood Building Baltic 2021 Accelerating low-carbon construction with wood – a Nordic Policy Snapshot| Craig and Jensen

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2. Joint Nordic challenges and opportunities Reducing emissions while building healthy, green and liveable Nordic towns and cities is possible through increased use of wood in construction. The Nordics have some excellent examples of this and policies in place to deliver towards those goals, but meaningful scale is still to be reached. To achieve the shared Nordic vision of a low-carbon and circular construction sector that uses more wood, we believe that the following six questions must be addressed by the industry and policymakers.

2.1. How to better support the local bioeconomy and fill supply chain gaps whilst integrating digital technology in the Nordics? The Nordics can deliver large amounts of sustainably sourced forest-based construction materials which is a prerequisite for a genuinely sustainable wood construction industry. Additionally, the region stands at the forefront of digitalisation. The challenge: Nordic production capacity to turn those raw materials into building elements such as CLT and glulam cannot keep up with demand, forcing projects to source from elsewhere with associated increase in costs and emissions. Digitalisation must be integrated through the entire supply chain to reap the benefits that it can offer in traceability and LCA.

2.2. How to create pathways to legally-binding emission limits and agree on the required methods and data? As LCA-based regulations and climate declarations are forthcoming across the Nordics, greater knowledge on the climate impact of construction and materials is being developed in the industry. Additionally, strong pan-Nordic collaboration on harmonising methods is well underway. The challenge: without a long-term vision to legally-binding emission limits as well as agreement on the tools, data and methods for calculating lifecycle emissions, progress here will falter and industry’s potential to get ahead and utilise that to their advantage will be capped.

2.3. How to better link and align Nordic expertise, build and share competencies towards a shared vision and become greater than the sum of our parts? The Nordics have world-leading knowledge and skills, with formidable competences in sustainable forestry, design, architecture, engineering that are being applied to advancing wood in construction. This is a powerful export and makes the region well-placed have wider influence at European and global levels. The challenge: these competences are not evenly distributed in the Nordics; greater integration, coordination and knowledge-sharing is needed, especially among the many intermediaries in the sector.

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2. Forum Wood Building Baltic 2021 Accelerating low-carbon construction with wood – a Nordic Policy Snapshot| Craig and Jensen

2.4. How to adjust building regulations to make it easier for innovative new building materials to penetrate the market? Performance-based and material neutral principles have become a cornerstone of Nordic building regulations, meaning that at least in theory wood can compete with other materials on a level playing field. The challenge: there is still a tendency towards conventional and polluting materials and ways of working. The handling of regulations sometimes lacks the flexibility to deal with the nuances of wood, for example, making the process more cumbersome for new lowcarbon materials to gain approval.

2.5. How to enable all local municipalities to build more in, and develop capacity in municipalities less experienced in lowcarbon construction? Nordic Municipalities have proven to be crucial actors in accelerating low-carbon wood construction locally. There are many good examples how local strategies in procurement, collaboration and clustering can be powerful tools. The challenge: municipalities could move even further and faster with greater freedom and creativity in the tendering process, and despite some leading hotspots, ambitious local action is not widespread, with great regional disparities.

2.6. How to better calculate and finance the carbon removal potential of Nordic forest products and bio-based buildings? As frontrunners in tackling the climate emergency, with abundant knowledge and resources, the Nordics are already well underway in transitioning to a low-carbon, circular, and increasingly bio-based built environment. The challenge: there is still lack of agreed methods on calculating the carbon sequestration and storage that wood in construction represents and linking that to

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2. Forum Wood Building Baltic 2021 Accelerating low-carbon construction with wood – a Nordic Policy Snapshot| Craig and Jensen

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financial mechanisms that fund carbon removals, which would change the economic case for building in wood substantially.

3. Results and discussion While there is consensus across the Nordics that wood can play a central role in reducing emissions from construction, each country has taken a different approach to achieving that goal. In this section we deep dive into the policy approaches taken in each Nordic country, noting strengths and weaknesses, and allowing Nordic neighbours to compare notes and learn from each other going forward.

3.1.

Finland

Forests have more political, cultural and economic importance in Finland than much of the rest of the Nordics, accounting for 2 % of GDP but over a fifth of export earnings. Finland’s forestry sets the gold standard in producing sustainable forest products, with high levels of digitalisation, through use of big data and digital tools. While Finland has been quietly getting about the work of building in wood for many years, uptake of wood in multi-storey buildings remains slow. Experience suggests, however, that attitudes are changing towards wood and the cost argument is being debunked time and time again. At a national level, there has been a demonstrated long-term commitment to improving the market penetration of wood over the past 20 years through the funding of multiple initiatives and ambitious target setting. For example, the government recently set a goal that 45 % of all public construction in 2025 should be from wood, up from only 15 % in 2019. At the heart of national policy efforts is a dedicated Wood Construction Programme of the Ministry of the Environment which provides a central guiding force to advance the wood agenda both within and outside government. The results of those efforts are starting to pay dividends in the past few years, with a marked uptick in wood’s share in construction. Below is a breakdown of some of the key policy areas in Finland that are enabling or hindering wood in construction. Regulation Like the rest of the Nordics, performance-based and material neutral building regulations have been mainstreamed in Finland for some time. Updates to the building codes in 1997 and again in 2011 have permitted wood construction up to four then eight floors without having to meet additional fire requirements. One point of difference on fire regulation in Finland is the ruling principle of protecting people and evacuation times. This is different to Sweden’s approach, for instance, which makes harmonising such regulations cross-border tricky. Finland has been slightly ahead of the curve having published a roadmap for low-carbon construction back in 2017, which included a goal to incorporate LCA into the building codes by mid-2020s.

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2. Forum Wood Building Baltic 2021 Accelerating low-carbon construction with wood – a Nordic Policy Snapshot| Craig and Jensen

Public spending on construction of new buildings in Finland is around €1.5billion annually, and policy has been developed in the form of voluntary green public procurement (GPP) criteria for low-carbon public buildings to harness the power of public procurement to accelerate the use of wood. These will be updated in the future to keep GPP at the forefront of ambition. Research and Development Competences As well as the many strong education Finland’s many strong research centres institutions in Finland that are working and applied science universities that have with wood in construction through a focus on developing skills and knowledge vocational and academic programs, for the next generation of wood competence building is also taking place construction are also leading on R&D in the particularly around circular within the industry and at a municipal field, level. For example, the government has construction. funded a successful training programme for structural engineers to bring them up to speed with new materials and methods in construction. This has proved a useful way to shift out of conventional ways of working. Finland’s many strong research centres and applied science universities that have a focus on developing skills and knowledge for the next generation of wood construction are also leading on R&D in the field, particularly around circular construction. An additional focus of the National Wood Another success of the national Wood Construction Program has been to increase Construction Program has been to launch know-how at a local level and support R&D projects in collaboration between municipalities in their decision-making industry, academia and the authorities. processes. Marketing and Advocacy Another role of the Environment Ministry’s Wood Construction Program is the promotion of wood both within government and more widely. This ensures that there is a voice speaking for wood construction at the governmental table, so to speak. In addition, there are trade associations and other bodies that do good work to promote wood in construction nationally, although international presence and representation could be improved to strengthen the export of timber construction expertise from Finland. What policies are on the horizon? Following on from the government’s low-carbon construction roadmap, compulsory LCAbased emission limits on new buildings should be introduced by 2025 or earlier in a timeline that is currently being developed. This should help to strengthen the case for wood, while work on establishing a common database to work from is ongoing. By 2025, the aim is also that 45 % of public construction should be in wood. A second key area in which Finland is leading the way on policy development is around the building ‘handprint’ concept, which aims to formalise the positive carbon impacts of new construction (through carbon storage or renewable energy generation, for instance). It is proposed to integrate this into the LCA methodology which could be a game-changer in assessing, accounting for and ultimately financing avoided emissions. Key challenges and successes 1. The national Wood Construction Program’s position in central government is unique amongst the Nordics and has yielded impressive and holistic policy results. 2. Despite a small uptick in recent years, wood multi-storey buildings are still struggling to achieve significant market penetration in the residential market.

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3. Work to include the carbon handprint of buildings in LCA could be critical in dramatically changing the case for wood construction in the coming years.

3.2.

Denmark

Compared to its Nordic neighbours, Denmark’s forestry and wood-based industries are small, with the volume of timber and roundwood production around 5 % of that in Finland, for example. As such, forestry does not account for a huge proportion of the economy of jobs in Denmark. Despite a handful of good examples, mass timber construction in Denmark has until now lagged a little behind other parts of the Nordics, although that is beginning to change. Tackling carbon emissions in Denmark’s construction sector has been rapidly rising up the political agenda, with wood’s underutilised role in the material mix gaining particular traction since 2019. Discussions in Parliament and Government are ongoing through a growing number of hearings and consultations examining the potential policy levers to build more with wood, but substantial wood policy is yet to be decided upon. Below is a breakdown of some of the key policy areas in Denmark that are enabling or hindering wood in construction. Regulation Denmark’s building codes are, at least on paper, performance based and material neutral, but wood still faces some additional barriers in this area. To meet fire safety requirements when building higher than four storeys, individual technical assessments are needed in planning due to a lack of pre-accepted solutions, and wood buildings must withstand longer burn times (120 minutes) than other materials (60 minutes). On site acoustic testing during the construction phase is required in Denmark, as opposed to being able to model acoustics to meet regulation at the design stage. These factors can be seen to have hindered the development of wood construction, as they create greater risk and costs for developers. Municipalities are proving to be critical actors in Denmark for driving an increased uptake of wood in construction, especially through public procurement. However, regulation is somewhat restrictive in allowing local authorities to stipulate LCA demands in the tendering process for example, which could lead to more public buildings in wood. Research and Development Competences Denmark has strong competences in There are a handful of university architecture, design, and urban planning, departments ‒ mostly engineering ‒ which have not been fully leveraged to working on LCA, but Denmark is not home accelerate wood in construction. to any notable wood-focused research centres driving home-grown R&D. Limited policy has been introduced to develop competences for wood construction, and while interest is growing at a student level, teaching competences within Danish institutions could be stronger to meet this demand and equip the next generation with skills and knowledge for wood. Additionally, industry must take greater responsibilities for building competences in house. Marketing and Advocacy Given the small size of Denmark’s forestry sector, it is home to numerous organisations and networks aiming to accelerate the development of wood in construction nationally through marketing and advocacy. Several notable Danish stakeholders are also involved in wood in construction network projects at a European level. Policies are on the horizon The dominant forthcoming policy in this area in Denmark is the introduction of ‘sustainability class’ for construction, beginning a test phase in 2020. The ‘sustainability class’ is a holistic attempt to improve not only the climate impact of buildings through

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2. Forum Wood Building Baltic 2021 Accelerating low-carbon construction with wood – a Nordic Policy Snapshot| Craig and Jensen

LCAs, but also other issues including resource use, indoor climate, natural light etc. The initiative is initially voluntary, but may become mandatory by 2023, with no indication given to date of LCA-based emission limits being imposed. This policy has buy-in from industry and gives a clear pathway in the short term, but greater certainty is needed on the long-term goals, and how the industry will develop sufficient competences. Additional discussion is currently underway to raise the current floor limits for timber construction in regard to fire regulation, which would surely remove one barrier to building more with wood. Key challenges and successes 1. The ‘sustainability class’ is a well-rounded policy that with further development – through the establishing of limits on lifetime CO2 emissions for example – could lead to greater utilisation of wood. 2. Challenges remain in fire and height limits for wood buildings, which should be addressed going forward. 3. There remain underleveraged competences in engineering, architecture and design, and greater efforts could be made to direct these skills towards wood in construction.

3.3.

Norway

Norway’s forests, while covering less land area and being less productive than Sweden and Finland’s, remain an important resource to the development of a growing bioeconomy. Wood’s potential to reduce construction emissions hasn’t gone unnoticed in Norway, which has some excellent lighthouse projects including the world’s current highest timberframed building, Mjøstårnet, and wood is now the leading construction material in schools and kindergardens. Imports of building materials – including wood – are increasing, highlighting the importance of further developing local wood supply chains to meet growing demand. Wood in construction doesn’t receive the same central focus in the Norwegian Government’s policy as in Finland for example, instead being included in the fringes of government strategies on bioeconomy, forestry and climate mitigation. However, Norway’s world-leading goal of carbon neutrality by 2030 and the fact that 10 % of national emission stem from construction materials has brought renewed attention to wood solutions in construction. Local and regional actors in Norway have been particularly crucial in the development of wood construction, and have a great deal of autonomy to push down construction emissions through the use of wood. Below is a breakdown of some of the key policy areas in Norway, that are enabling or hindering wood in construction: Regulation Norway no longer strictly limits the number of floors that can be built in wood, having moved more towards performance based regulation regarding materials. Despite this, fire regulations are still proving problematic for some wood construction projects to meet the requirements. While national regulation has not been hugely helpful in advancing wood in construction, the flexibility of local and regional planning authorities to go further has yielded some impressive results. This has primarily been achieved through masterplans, and the ability for planning authorities to introduce requirements that mandate use of renewable building materials for example. Norway has recently introduced the NS 3720 standard to bring a common way of working with climate assessment of buildings, but any moves towards climate declarations or limits are still under discussion. Research and Development Competences Norway has several established and R&D and stimulating innovation have been successful centres for research and at the cornerstone of Norway’s policy teaching around wood construction that efforts to increase wood in construction, are leading on building competency. primarily through the bioeconomy and Experiences suggest that student uptake forestry strategies.

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on wood-related courses is increasing, demonstrating a positive growth in interest amongst the industry’s next generation.

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The government, under the auspices of Innovation Norway and the National Research Council has run numerous projects aimed at increasing value through the entire forestry chain, notably including the ‘Wood-based Innovation Program’, an initiative to increase competitiveness of timber-framed multi-storey buildings and value-added processing in for that sector.

Marketing and Advocacy Norwegian wood trade associations have long established relations within the construction sector, and have been effective at promoting wood solutions in construction as well as guiding municipalities through the process of building with wood. These organisations have however not focused many efforts on advocating for policy changes at a national level. Other initiatives and partnerships, such as the ‘wood ambassadors network’ which is partly funded by the regions and municipalities has helped to forge new connections across the value chain and brought wood into consideration on many construction projects. What policies are on the horizon? Regulation of construction emissions and climate declarations is still under consideration at the time of writing. While it is clear that new technical declarations are forthcoming, it is currently unclear exactly how carbon emissions will be integrated into this. There is promise however, given the established standards for calculation and interest in creating joint Nordic LCA databases. It is expected that over time climate declaration requirements and eventually scaling emission limits will be introduced. The question remains on the ambition of the timeline that the government will set in that regard. Key challenges and successes 1. Norway leads in R&D and innovation, as demonstrated by some of the groundbreaking timber buildings that have been built in recent years, but now faces the challenge of scaling across the construction sector. 2. With increasing demand for wood construction elements, it’s crucial that production using locally and sustainably sourced wood grows as well, to ensure that the benefits reach across the entirety of the Norwegian wood value chain. 3. A long-term pathway must be set out to give clarity on the future of climate declarations and future emissions reduction targets within the sector, ensuring that national ambition matches that shown by regions and municipalities.

3.4.

Sweden

Sweden has the most forest area and highest wood production of any Nordic country, which has a large importance for the jobs and economy with over 25,000 people employed in forestry and forest-related industries in 2018. There has been a strong drive for wood in construction over many years in Sweden, which today is seeing significant uptake in multi-storey buildings. This is especially true in residential construction, which makes up a greater proportion (around two thirds) of the market than in the rest of the Nordics, although wood is still considered an underutilised resource. Sweden is often held up as an example internationally for the steps it has taken to realise the potential of wood in the construction supply chain, while developing local bioeconomies and cutting carbon emissions. This has been enabled by a pro-wood policy landscape over many years, but wood could still play a greater role in the material mix, and is an issue that is attracting renewed interest at a ministerial level, and new policy developments. Below is a breakdown of some of the key policy areas in Sweden, that are enabling or hindering wood in construction:

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2. Forum Wood Building Baltic 2021 Accelerating low-carbon construction with wood – a Nordic Policy Snapshot| Craig and Jensen

Regulation Sweden’s building codes are both material neutral and performance based, and experience suggests that wood constructions do not face any significant additional hindrances from a regulatory perspective. One key enabling factor in Sweden’s wood construction progress has been the lifting of any height limits on wood buildings over 15 years ago, which sent a clear signal to developers and designers to go all in for large multi-storey wood buildings. Other factors such as the ability to use digital models at the design phase to meet acoustic requirements rather than laborious on-site testing have been further enabling policies for forest-based materials to gain traction in the market. Competences Research and Development The most notable way in which Sweden R&D in Sweden is driven by substantial has developed competences through the public funding for research into the supply chain is in the unique collaborations practical application of material science of between industry, academia and local wood across the value chain. The most government. This is built upon a base of effective examples are collected in clusters several education institutions with around related expertise that lead to new strengths in wood and construction. and innovative ways of working. Such developments are no accident, but rather the result of targeted public funding to establish and support specialist centres of excellence. Marketing and Advocacy With the importance of the forestry sector to the Swedish economy and jobs – as well as the country’s sheer size – there are many organisations and initiatives working to promote and advocate for wood in construction. Sweden has done more than most other Nordics countries in marketing its wood solutions to a wider international audience, and has reaped the benefit from that in export of knowledge and goods. What policies are on the horizon? The most significant current policy development is the introduction of a requirement from 2022 for all new buildings to submit a climate declaration on emissions from production and construction phases (A1-5). This must be completed and cleared by the local municipality before construction begins. Initially simply declaring the emissions is all that will be required, and it is proposed that emission limits will have to be met from 2027, with 40 % and 80 % reductions by 2035 and 2043 respectively. Additionally, more stages of buildings’ lifecycle emissions will be gradually introduced into the declarations. The result of this clearly laid out timeline is expected to be a greater knowledge in the sector on CO2e emissions per m2, which can put wood on a more even footing with other materials. Key challenges and successes 1. A full roadmap for the rollout of the climate declarations and legally binding limits and reductions is needed to strengthen this policy and enable the industry to adapt accordingly. 2. With growing demand for wood construction elements not only nationally but also for export, Sweden must grow its production capacity to keep its leading position. 3. Swedish success in wood construction could be better transferred through greater efforts for Nordic harmonisation and cooperation.

3.5.

Iceland

Iceland is an outlier in the Nordics when it comes to forestry and forest-based industries in that they are almost negligible. While a tiny amount of forestry takes place, it is very much at a pilot stage in terms of producing anything suitable for construction. Iceland imports almost all of its building materials, with the exception of mineral wool, causing difficulties when it comes to accounting for the emissions related to materials produced

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elsewhere. Despite the fact that timber construction elements, with a high strength-toweight ratio, offer an effective solution in this regard, uptake of wooden multi-storey buildings in Iceland is very low. Iceland has done a great deal of work in policy development over the past decades to reduce operational emissions from buildings to almost zero through renewable heat and power. This means that although emissions embedded in materials may be high, overall building emissions are generally low when seen from a LCA perspective. Unlike in other Nordic countries, Iceland has not actively pursued policy to encourage the use of wood in construction. Today’s building regulations in Iceland are not material specific, but performance based, and have been simplified in recent years. The lack of penetration of wood construction can be attributed to a lack of knowledge, experience and competence in building with wood in Iceland, although several research and pilot projects are beginning to examine its potential. Lacking a domestic forestry industry doesn’t help here, as there aren’t the additional drivers towards wood in the form of trade associations and other third parties. What policies are on the horizon? Work is underway to develop a roadmap for sustainable construction in 2030, which should include some aspects of LCA. It is as yet unclear whether forthcoming legislation will require climate declarations as in other Nordic countries. In the government’s latest climate plan, renewed research efforts were announced to push towards a circular and low-carbon construction sector in Iceland, bringing together new partnerships to achieve this goal.

4. Conclusions The scale of the climate and biodiversity crises requires that construction sector urgently become part of the solution. The Nordics talk the talk when setting goals, but the success of the policies is contingent on sufficiently ambitious limits being set at national levels. Through regulation, governments can create first mover advantage for Nordic companies, from which a globally frontrunning industry can become exporters of knowledge and solutions. It creates the conditions of a Nordic ‘high-altitude training camp’ for designers and construction companies – big or small, urban or rural – to become greenest in the world. Within the Nordics, we have high but unevenly distributed knowledge for how to achieve our shared goals. Improved steps to break down cross-border barriers will make the region stronger as a whole and be an important step for achieving the vision on the Nordic region becoming the most sustainable and integrated region in the world by 2030.

5. Acknowledgements This publication was prepared in late 2020 by the Nordic Wood in Construction Secretariat1, through analysis of national policy documents and interviews with experts in each Nordic country. Additional insights were gained from a series of expert roundtable dialogues, and learnings from the secretariat’s activities from 2018-2020. Acknowledgement must go to all those who have given input to this work, and those who have taken part in interviews and roundtable dialogues; your insights have been invaluable. The team behind this report, the Nordic Wood in Construction Secretariat, is an initiative commissioned by the Nordic Council of Ministers and the Swedish Government, and hosted by EIT Climate-KIC, with an aim to support and accelerate the use of wood in construction in the Nordics. They do this by improving regional dialogue, knowledge-sharing and collaboration on wood in construction, and sharing Nordic solutions with the world. More info at www.woodinconstruction.net

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2. Forum Wood Building Baltic 2021 Sustainability and Health, case of a Day Care center in Salaspils/ Miķelis Putrāms

Sustainability and Health: the case of a Day Care Centre in Salaspils Miķelis Putrāms, Architect, MADE arhitekti, Latvia Key words: timber kindergarten, fire protection, CLT, timber, GLULAM, passive house

Timber building for kids In 2018, MADE arhitekti won a competition to design a kindergarten in Salaspils municipality. During the design phase, the design team together with the client defined high environmental criteria, that will be based on the need for rational use of resources in the long term. Due to short-term decisions the building industry has become environmentally damaging to the climate of the earth as well to health of people as well. There are several studies in Latvia that show that new and renovated buildings are bad for the health of children due to use of toxic paints, materials and bad ventilation of rooms. The project addresses issues regarding health in educational buildings as well as those stated in the European Green Deal and NEW Bauhaus. Energy efficiency Today the regulations for public buildings require to design “almost zero energy building” that translates into a 45 kwh/m2a energy requirement for heating and primary energy less than 110 kwh/m2a. Due to extremely compact volume and good A/V ration of the building, the design calculations fall in between the Latvian definition of “almost zero energy building” of 45kwh/m2a and German passive house standard of 15 kwh/m2a with a reasonable thickness of insulation. Due to inconsistencies of calculation methodology and necessary assumptions (air change rate) according to difference in norms, the building energy at the design stage is calculated for heating 29 kwh/m2a and primary energy for 85.63 kwh/m2a. In fact, the calculations according to the passive house methodology and PHPP shows that building will meet the passive house energy standard <15 kwh/m2a for heating.

Fig. 1. The energy certificate according to Latvian norms, design stage.

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2. Forum Wood Building Baltic 2021 Sustainability and Health, case of a Day Care center in Salaspils/ Miķelis Putrāms

Low-carbon materials

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The intention to reduce embodied carbon resulted in the idea of an all timber building made out of glulam frame and CLT walls, floors, roof and facade on concrete slab. The main challenge for all timber construction lies in the fact that according to the Latvian building norms regarding fire protection a building for children shall not have more than one floor in timber. Also, the necessary area of ~3000 m2 of floor space is not allowed to be built and has to be to divided with non combustible fire partitions.

Fig. 2. Timber structure of the building During the design phase, an alternative fire protection concept with fire escape simulations was developed and presented to the fire department of technical committee, the only institution authorised to approve deviations from building norms. Thanks to fire protection engineer Edvins Grants and structural engineer Gatis Vilks, the document for approval was designed; it included the fire protection concept, evaluation of Latvian building norms, preliminary calculations for fire resistance of structure. The design team visited Sweden with the support of Swedish passive house organisation and Tommy Westlund. The knowledge of Swedish kindergartens were used to design the fire escape strategy using external stairs from the first floor to provide safe and smoke protected escape route. The safe and very well thought through fire escape routes, also for children with special needs, was the main argument to accept deviations. The calculated R60 structure and REI60 CLT fire partitions protected with two layers of A2 gypsum boards provided extra arguments. Finally, the utmost care about the indoor environment and neglectance of any chemical wood protection materials provided extra argument. As a result, the approval from the Fire Department was received to allow several deviations from the code regarding mostly the reaction to fire B to D; A2 to D nevertheless to include extra fire protection measures of fire resistance, escape routes, etc., including special request for reaction to fire of electrical cables. This is the first building in Latvia

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2. Forum Wood Building Baltic 2021 Sustainability and Health, case of a Day Care center in Salaspils/ Miķelis Putrāms

that has timber fire compartment partitions that are composed of combustible materials (140 mm 5layer CLT) encapsulated in 25 mm of gypsum layer from both sides. Healthy indoor environment. Only carefully selected indoor finishing materials were used. The timber surfaces are covered with white tinted OSMO hardwaxoil. Linoleum FORBO with crushed coconut shells covers the floor. In heavy use rooms there is NORMA rubber floor. Furniture is made mostly of 3-layer 16 mm spruce boards. The ceilings are made with an air gap, covered with wood cement fiber boards, that is used for air distribution to classrooms.

Fig. 3. Palette of interior materials The ground bore holes with environmentally sound liquid circulation system are used to provide ventilation air precooling in summer and preheating in winter. The use of overflow cascade ventilation system reduces the overall necessary air change. Due to the use of eco materials inside the rooms, the air change is maintained reasonably low to avoid too much air change and dry air in winter. The exterior surfaces of playground and facade are environmentally sound without use of biocides and toxic wood preservatives. ORGANOWOOD treatment is provided for playground elements, site terraces and sitting furniture as well for timber facade.

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Fig. 4. Façade of the kindergarten in Salaspils municipality

Fig. 5. Interior of the kindergarten in Salaspils municipality Conclusions The discoveries and findings during the research and design phase show that there are viable solutions for energy efficient low carbon, healthy materials and solutions. The problem lies in regulations that focus on narrow aspects of construction without considering the actual need for sustainable and “green” solutions. The authority and leadership of architects and support of client and design team, and other supporting organizations and material producers is crucial to overcome the obstacles and deliver projects that conform to future standards of “green deal” and move the construction towards circular economy. It is clear that Latvian building norms and bureaucratic institutions that are responsible for the quality control of projects are outdated and do not support sustainable design solutions.

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2. Forum Wood Building Baltic 2021 Birch plywood RIGA ECOlogical with lignin based glue | Maris Bumanis

Birch plywood RIGA ECOlogical with lignin-based glue Māris Būmanis, Executive Board Member, Latvijas Finieris, Latvia

As the global leader of performance-orientated birch plywood-based product solutions, we at Latvijas Finieris are conscious of the need to change the existing industrial patterns to build a sustainable and safe future. Therefore, together with Stora Enso, the world leader in the chemical and mechanical forest industry, we have developed a new plywood bonding solution ‒ green glue RIGA ECOlogical, where bio-based renewable lignin to a significant extent is used as replacement of the traditional fossil products including phenol and formalin. This new lignin-based glue significantly reduces the carbon footprint of plywood products all the way from production to final end-use applications without compromising on technical performance. Key words: birch plywood, green glue, bio-based renewable lignin, reduction, carbon footprint.

1. What is lignin? Lignin is an organic substance binding the cells, fibres and vessels which constitute wood and the lignified elements of plants. After cellulose, it is the most abundant renewable carbon source on Earth. Lignin is a wood component that gives plants shape and stability as a kind of connector, thus solidifying the cell wall. Industrial lignin is usually extracted from wood as a powderous by-product in chemical «Kraft» pulp production. Still until the 2000s, the main use of lignin has been energy production by burning. Recently lignin has become an important subject to active research to develop new and more sophisticated uses for it. RIGA ECOlogical is one of them.

2. RIGA ECOlogical ‒ Why it matters? By including plywood with lignin glue in our portfolio, we want to give our clients an opportunity to make a change with us and thrive for better living and working environment. 2.1.

Environmental Product Declaration

Our Environmental Product Declaration shows that the major environmental performance indicators for birch plywood have improved whilst using RIGA ECOlogical. •

Potential environmental impact has decreased by up to 49 %.

Including Global warming potential environmental impact has fallen by 26 %.

Significant reduction of waste and optimised use of non-renewable energy resources in the procurement and production of plywood raw material.

2.2.

Reduction of volatile organic compounds (VOC)

Reducing VOC content considerably improves air quality and therefore is a vital factor for people’s well-being. Only together we can build better environment. The internationally recognised certification systems allow to compare the environmental impact of building projects as well as to maintain a sustainable development and healthy living conditions. RIGA ECOlogical not only meets the BREEAM and LEED requirements for formaldehyde and VOC emissions but even exceeds them and assures that projects support sustainable development and building practice as well as secure an environment that does not peril health.

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2.3 Declaration of performance RIGA ECOlogical plywood has been successfully tested in the laboratory, in production and in most demanding industrial end-uses. Results show that all technical properties of worldleading high-performance RIGA plywood when using RIGA ECOlogical remain equal to standard RIGA EXT glue. According to certification and continuous surveillance, both EXT and EXT-LN bonded RIGA plywood are marked CE 2+. •

Bending strength EN 310

Modulus of elasticity EN 310

Bonding Quality EN 314

Class 3 (exterior)

3. Conclusions Society is changing and we want to be part of the change. People are demanding healthier food, greener products, efficient use of resources and better living in a sustainable environment. Being responsible in our own actions, we are integrating sustainability principles deeply into our production processes and product concept. RIGA ECOlogical is one of the steps how we are doing our part for the planet whilst giving you the opportunity to do yours together with us.

Figs. 1‒3. Skriveri secondary school library with Riga ECOlogical interior.

4. Acknowledgements Business Development team: Stora Enso Product Development team: Latvijas Finieris AS

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2. Forum Wood Building Baltic 2021

Timber Construction Competence Center | Argo Saul

Timber Construction Competence Centre Argo Saul, EMBA, Nordic Houses OÜ, Chairman of the Management Board, Estonian Wooden Houses Cluster, Estonia

Summary Timber Construction Competence Centre is the newest exhibit at Estonian Open Air Museum in Tallinn and has been created as a gift for the 100th anniversary of Estonia. The extraordinary joint project, exhibited for generations to come, united more than 100 partnering companies that all contributed with their services, materials and products. Key words: contemporary architecture, prefab production, timber construction, smart house technologies, cooperation, CSR.

1. Introduction Estonia is a country of forest with centuries long timber building traditions. Knowledge and dedication have made Estonia the largest wooden houses exporter in Europe. The idea of the latest exhibit in the museum is to present architecture and timber construction technologies of the 21st century already now. Why wait 50 or 100 years?

2. Output and project activities The architectural concept was selected from amongst more than a 100 projects presented at annual contests “Pre-Fab House of the Year”, and it is an award winning Nordic COMPACT by Estonian AB Trilog Studio OÜ, in 2015. Argo Saul took the lead and made the project happen on behalf of Puiduklubi MTÜ (NGO Club of Wood). Contract with the Estonian Open Air Museum was signed on August 22, 2018. Preparation works of the plot started on March 12, 2019. Assembly works started on May 24, 2019. Opening of the sector showroom together with celebration of 20 years of Estonian Woodhouse Association took place on August 31, 2019. The project had no budget or a client, as it was a gift. It did not require a building permit. The criteria from the museum were that the new exhibit should be a 21st century home that has already been built somewhere. The design of a residential house needed to have a possibility to be adjusted to fit the needs of public office building, including a sector showroom, meeting room, 3 offices, kitchen, restrooms, archive and technical room. The architectural design is a whole that reflects a range of modern technologies and materials, follows sustainable building principles, consists of a main house with additional modules and a side building. There are different timber construction technologies combined: prefab timber-frame delivered to the site as elements and pre-cut details, cross laminated timber (CLT) and solid wood wall (MHM) delivered to the site as module and elements. Painted cladding boards and heat-oiled glue laminated wood have been used in the exterior finish. Terraces are of thermowood and accoya wood. In the interior wood based materials were used. The centre has 2 integrated solar stations, smart house solutions ‒ remote controlled ventilation, heating, lighting and digital door keys. The building´s systems can be monitored via mobile app and over the internet.

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Timber Construction Competence Center | Argo Saul

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3. Results and discussion Contributing partners believe that the Competence Centre helps to share knowledge about processes of timber construction and strengthens cooperation in the value chain. The project also reflects traditions of wooden construction in Estonia and aims to prolong those traditions today and in the future. This project can be considered as a good role model in order to increase the share of timber construction locally (sector export share currently is 90 %).

Fig. 1 (left). The Timber Construction Competence Centre. Fig. 1 (right). The architectural concept of Nordic COMPACT.

4. Conclusions With the new exhibit, the story of Estonian wooden houses is enriched. Both the people planning their own home as well as professionals benefit from the competence centre that provides them with thorough information about modern technologies and possibilities of timber construction, ideas how to build nature friendly houses and lead a sustainable lifestyle.

5. Acknowledgements • • • • • •

Contractual partners: Estonian Open Air Museum and Club of Wood Architects: Trilog Studio OÜ Main contractor: Nordic Houses OÜ Investors: 100+ companies Showroom: Estonian Woodhouse Association / Cluster and Enterprise Estonia “Friend of Culture 2018” award by Estonian Ministry of Culture

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2. Forum Wood Building Baltic 2021 Timber in constructions: how to be effective | Audrius Papėčenka

Timber in constructions: how to be effective Audrius Papėčenka, Effective Solutions, Lithuania

Summary There is a growing demand to use mass timber in construction. The demand for the quality of the services is also increasing. Therefore, the aim of this paper is to discuss challenges on site which have major impact on effective timber construction process. All the insights are based on Effective Solutions experience in mass timber projects. Key words: mass timber, construction planning, CLT, glulam, assembly.

1. Challenges in timber construction Mass timber structures are low weight and their construction process is quicker than building from concrete or steel. The construction site is much cleaner and producing less waste. However, building from wood, especially from prefabricated elements, involves more early planning comparing to using other materials.

1.1. Assembly sequence Assembly sequence is one of the key things directly impacting the speed of the assembly. Having quick timber structure assembly allows to start other works (engineering systems, finishing works, etc.) in parallel. However, it challenges the main assembly process, as many different teams start to work under one area simultaneously. It requires advance planning and communication to keep processes uninterrupted. However, the most important aspect is logistics. If possible, the elements should come to the site (or hub) following the assembly sequence, avoiding storing them on site for longer period of time. It requires daily communication with logistic partners and constant flow of the delivery trucks. An example of effective assembly sequence planning is Moxy Utrecht (Netherlands) project. As it was a compact site, it was important to store only relevant elements that would be installed in the following days. Other parallel works (engineering systems, finishing works) had started approx. 1 month after the first timber elements had been

Fig. 1. Site plan for CLT assembly.

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installed. Structured assembly sequence was very important to finish the project in time. The area of the project was approx. 6500 m2. The assembly of prefabricated timber elements was completed in less than 3 months.

Fig. 2. Moxy Utrecht (2020) project after all the timber elements were installed.

1.2. Rain protection The factor is mostly common for wooden structures, especially for prefabricated elements. To assure efficient water protection during the assembly, water prevention plan has to be agreed in advance. As it was previously noted, it should be avoided to store elements on site for longer periods of time. After the timber elements are installed, there are a few most common ways to protect timber: - Plastic films or reusable tents (tarpaulins). Plastic films are probably the most common way of protection. Though, as it is not reusable, it creates a lot of waste. Tents (tarpaulins) are reusable and more durable comparing to the plastic films. - Additional roof. The most effective option but also the most expensive. - Steel sheets. Effective option but takes the most time (considering other options) to install. All these options can be applied. Even the protection with plastic films and tarpaulins can be sufficient. The effectiveness depends not only on the option itself but also on the methodology applied. In early planning stage the assembly sequence should be adjusted in order to have the maximum benefit from the covering system. In the end of the day the elements should be assembled having horizontal surface which could be covered to assure rain drainage. It is also important to reserve considerable assembly time to assure proper rain covering.

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2. Forum Wood Building Baltic 2021 Timber in constructions: how to be effective | Audrius Papėčenka

Raiprotection options. Left ‒ Oslo (2016); top right ‒ Moxy Copenhagen (2018); and bottom right ‒ Moxy Oslo Extension (2019).

1.3. Health and safety Health and safety is one of the most important factors to consider in early planning. Safety measurements should apply according to the type of the structure and possible risks. The most common measurements are: - anchor lines; - collective protection systems (fences around the working area, scaffoldings, etc.); - personal protection equipment (helmets, harnesses, etc.). These measurements help to work safe during the assembly process, but sometimes they do not cover all the risks possible, especially for complicated structures. So, it is important to foresee these situations in early planning as much as possible and prepare the solutions for non-standard situations.

2. Glance at the structural design Effective timber assembly process is also dependant on efficient structural design. It is important to share experience between these two fields. Site manager (engineer) has to understand design solutions and give feedback to structural engineer. Usually, assembly sequence is set by structural engineer during production drawing phase. This is the process that requires collaboration between both parties. Swedish Pavilion EXPO (2020) is a good example of the effective communication between assembly team and structural engineers. The project is unique by its structure, as it is fully composed from timber (including foundations). However, due to its nature it required additional effort to build it. As foundation level was fully wooden, it was challenging to use mechanisms of any kind. All the used devises, machinery were limited to permitted load, which was important to control.

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2. Forum Wood Building Baltic 2021 Timber in constructions: how to be effective | Audrius Papėčenka

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Assembly sequence required additional attention not only of structural engineer, but also of an assembly team. Horizontal building stability is provided by the central building core so the elements had to be installed in the specific order to prevent instability during the assembly phase. For the assembly team it was important to understand structural behaviour and always communicate with structural engineers throughout the assembly phase. Many adjustments in the design were made following feedbacks from the assembly team.

Fig. 4. Swedish Pavilion EXPO (2020) project: foundation area 1875.4 m2; around 2600 m3; more than 2400 elements; 3.5 months of assembly with 7 workers.

3. Conclusions Building from wood has a lot of advantages. In order to use mass timber effectively, early planning and good communication are a must. Health and safety, assembly sequence and rain protection are the main aspects and are covered in this work. Also, it is worth mentioning a site planning, complicated geometry elements installation as other aspects to be considered. There always will be challenges on site. The majority of them should be overseen in the early planning process, but not all of them can be predicted. In that case good communication is necessary and qualified specialists on site to mediate non-standard situations.

4. Acknowledgements I want to thank Effective Solutions team members Andrius Pašiūnas, Aurimas Seilius and Dominykas Stankevičius for sharing experiences from their projects.

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2. Forum Wood Building Baltic 2021

Innovative connections for CLT and mass timber structures| Matteo Andreottola

Innovative connections for CLT and mass timber structures Matteo Andreottola, Technical consultant, Rothoblaas, Italy

Summary The aim of this webinar is understanding the innovative connections for CLT structures and be able to choose the right solutions for mass timber and CLT structures. The main topics of this webinar are the connection to the ground (a structural connection which guarantees durability too), shear connections, hold downs, and other innovative solutions for timber structures like Spider, Pillar, Sharp metal and Xrad. The webinar will explain the characteristics and the advantages of each solution and the engineering behind them following real application examples. Key words: timber, innovation, connection, CLT structure.

1. Introduction 1.1. Building with timber: the connections are the key The structures with timber have developed a lot in the last few years. Nowadays, we are building multy-stories structures entirely with timber, not only small structures like in the past. Thanks to engineered materials like CLT, LVL and Glulam and the increased knowledge on timber engineering, structural engineers found out that this material has many advantages for seismic design, for its resistance and low weight, for its sustainability and beauty. The connections for timber structures should be designed and engineered to follow this growth and make the innovation of timber structures possible. This webinar concentrates on the innovative connections developed to help designers overcome the limits of the material and design in the best way possible with timber.

2. Methods The main topics of the webinar are connections for CLT and mass timber structures. Innovative angle brackets, like TITAN, can withstand horizontal forces (for example, wind or seismic loads. They can be used for both timber-to-timber or timber-to-concrete connections, to transfer tensile and shear forces or the combination of both. An example is TITAN V with full threaded screws on the corner of the bracket, to minimize the eccentricity and increase the resistance. ALUSTART is a structural connection to the ground for timber panels, but it also guarantees the durability of the wood. It can be used to raise and level the CLT or timber frame panels. This type of connection can transfer shear, tension (with the use of holddowns), and compression to the foundation. The perfect levelling of the profiles is achieved using dimes (a linear one and an angular one for square angles). The geometry can be variable with different lengths and thicknesses. Screws and nails can be used for the fastening on the timber side of the structure and mechanical or chemical anchors for the concrete side. The ALUSTART can withstand the shear forces and, therefore, it does not need extra shear angle brackets but only hold-downs at the extremities of the panel. An extra advantage of using this solution is the time saving on site for positioning and fastening the elements and the precision of the installation as well. SLOT connectors can be used for the shear connection of CLT panels instead of screws and nails. With this type of connectors, it is possible to achieve a monolithic behaviour of the CLT wall. This type of solution cuts considerably the costs and the installation time because less connectors (with a higher stiffness and resistance) are needed.

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2. Forum Wood Building Baltic 2021

Innovative connections for CLT and mass timber structures| Matteo Andreottola

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Spider and Pillar connections make it possible to realize CLT structures without a secondary glulam structure, saving time, money and material, solving the problem represented by the compression perpendicular to the grain. Using this connection, it is possible to create a point supported CLT slab without the secondary structure, saving a lot of living space or room for the installations. The difference between Spider and Pillar is the following: the SPIDER connector has a series of steel elements with inclined full threaded screws which hang the floor and bring all the forces directly to the column. The PILLAR solves the issue of the compression perpendicular to the grain. The SHARP METAL is an innovative connector for timber structures which can be used to enhance the stiffness of a connection and increase the resistance. It is a steel plate with spikes which is installed with self-tapping screws. The advantages are the possibility to create collaborating structures increasing the stiffness with a simple and effective method. The XRAD technology is an innovative approach to connect CLT panels. It consists in connectors attached to the vertexes of the panel with inclined full threaded screws. They can be used to lift the panels as well and they have a much more resistance than the standard connectors.

3. Results and discussion In the webinar, all the design process of the products will be explained and discussed in detail. Rothoblaas has a team of engineers that are developing the products in order to meet the needs of the designers and resolve issues in the timber constructions. After the webinar you will be able to better comprehend the products, and, therefore, you will be able to design smart, optimized solutions for the timber structures and solve a lot of issues during the design process and on site.

Fig. 1. Render of a construction site with Spider connector (left) and the Pillar (right).

4. Conclusions Rothoblaas is a company which designs and develops solutions for timber structures. Innovation is important to make the most out of the advantages that timber is providing to structural design. I hope that this webinar will be of great interest to all the engineers and designers who design with timber and to the architects who want to know more about innovative connections for timber buildings. The key words are precision, speed, durability and the beauty and fire resistance of a hidden connection. The company is also a leader on the acoustic, which is considered in the design of the connections as well.

5. Acknowledgements A big acknowledgement to the whole Rothoblaas team who start from innovative concepts and new ideas and make them reality.

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2. Forum Wood Building Baltic 2021 Weather protection solutions ofexposed wood surfaces | Janis Vanags

Weather protection solutions of exposed wood surfaces Jānis Vanags, Head of Application Engineering Global, SIGA Cover AG, Switzerland

Summary Solid timber as structural and visual material faces weather management as one of the critical points when planning, producing and assembling horizontal timber constructions. The research was initiated as basis of development package for the material which can cover the following applications:  protection of timber horizontal surfaces during all building stages;  comply with the needs of work safety;  comply with other necessary functional properties for thermal envelope construction in different climates. Composition of material with low capillary moist capacity, high adhesive, abrasive, transparent and suitable for vapour control functionality was achieved. Key words: architecture, protection, moisture, timber surfaces.

1. Initial situation & target 1.1. Today’s solutions and related risks Today’s moist management solutions are mostly adaptations of the full adhesive nonwoven wind protection membranes which are originally designed for the vertical surface protection where thanks to kinetic energy it drives down the surface reducing risk of damages. Composition, where non-woven layers are independent from glue, provides the following risks for horizontal surface protection:  High capillary effect transports moist from exterior premisses under construction where end grain of timber elements gets influenced by the moist. The other aspect of this effect is resulting moist transportation from exterior to the interior premisses resulting in higher risk of any kind of damages for the inside surfaces.

Fig. 1. Capillary risks when using materials from vertical protection applications.  

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Mechanical influences where protection layer gets broken and because of capillary effect moist gets distributed. Low water vapour transmission resistance for vertical protection materials increases the risk when facing long term horizontal standing water. Transparency and abrasion properties for work safety and assembly precision.

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2. Forum Wood Building Baltic 2021 Weather protection solutions ofexposed wood surfaces | Janis Vanags

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Diffusion strength brings two functional factors. Firstly, production process where lots of dust effects the adhesive substrate and vacuum lifting requirements have to be met. Secondly, the moist substrate during installation on the building site.

1.2. The scope of the research & development 1. Conclusions of field tests for existing non-woven solutions. Property portfolio set for the future solution. 2. Composition of protection material with low capillary potential. 3. Mechanical property tests. 4. Moist measurements. 5. Diffusion capability and research for vapour control functional use. 6. Artificial ageing. 7. 3rd party tests.

2. Results and discussion 

Temporary horizontal protection applications compared with vertical holds much more damage risks, therefore materials with specific properties benefits towards the solution with reduced moist damage risks.

Material composition with low capillary effect has been developed where functional non–woven is impregnated with the acrylic glue reducing capillary effect to 90 %

Fig. 2. Composition comparison between vertical and horizontal solution. 

Mechanical, abrasive, and ageing properties can be achieved with modification of top layer.

Composition of the material allows to use it as vapour control layer in the thermal envelope constructions elements.

3. Conclusions Full adhesive temporary horizontal protection of timber surfaces can be achieved using non-woven membrane with adhesive impregnation in fleece layer. Protection as main functionality, vapour control functionality as secondary function provides market with weather risk free solution when planning, producing, and assembling timber constructions.

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WOOD IN ARCHITECTURE AND DESIGN Much Untertrifaller, Austria Kaspars Kurtišs, Latvia Timo Leiviskä, Finland Nicole Kerstin Berganski, Germany Oksana Hetman, Estonia Pēteris Supe, Latvia Juha Schroderus, Finland Peder Fynholm, Denmark Mihkel Urmet, Estonia

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Much Untertrifaller Alarnding Just nartner Dietrich | Fo Estonia Untertrifaller A stria

n chApril Untertrifaller st Design died architect the nienna 16th - 22: - Fire of I-joistsreinat Wall University of Technology. In md 29 s1 the s ccessf l AssemblieR collaboration with Helm t Dietrich began. In 29941 after winning the international competition for the Alar J st iss inaBregenz1 professor Tallinn of Festspielha they at opened theirUniversity joint practice Technology researcher at RISE Research Instit tes in Bregenz. and The acontract for the extension of the Wiener of Sweden.res Dr. Jlted st in has reg lar co rses at Linnae s Stadthalle a second ofce in also nienna. In e 51 University and London City in University. is a reviewer for they established a branch St ·allen1He joining forces with several jo ernals1 in the feldinofnaris wood stropened1 ct res Christofscientifc Stäheli. In 251 the ofce was and fre safetyy followed by an ofce in n nich in e 20. Since e 201 n ch Untertrifaller has been teaching as an honorary He is the head EstonianUniversity delegationofinApplied CEN TCSciences. e5 SC professor at theofKonstanz 5Heand member of - SC5.T4Association project team1 drafting is nresident of TCe5 the n Central of A strian the next generation of EN and 2995-2-e. Architects norarlberg member of the design advisory board ·raz1 Kassel1 Landsh t and Beza .

Nicole Kerstin Berganski NKBAK Architects Germany

Nicole Kerstin Berganski has gained her e4Cerience in renowned ofces for several years. She worked at SANAA in Tokyo for four years, the studio of Pritzker Prize winners Kazuyo Sejima and Ryue Nishizawa. In 2007, they established their own studio NKBAK, co-founder is Andreas Krawczyk. Since then, they have realized Crojects in a wide range of scales, from weekend houses to daycare centres and school buildings. In addition to utilizing classical materials, the architects have discovered and develoCed the Cotential of timber construction as a central element in their work.

Oksana Hetman Entonia

Kaspars Kurtišs Latvia

M. sc. ing. easpars eurtiss is CEO of engineering ofce e FORMA, a Board  e ber of Latvian Association of Structural Engineers, Me ber of Latvians Standardi)ation  Co ittee  S e . 5e is a certifed structural engineer and expert and has ore than 15 years experience in structural design, expertise and construction industry.

Oknana Hetman in an architect with demonntrated hintory or workini in internationau companien on renidentiau compuexeng medium and uarieencaue honpitauity projectng pueuic nchooun and pri ate architecturau projectn on auu ncauen and ntaien. Currentuy nhe in workini with TEMPT architectn on renidentiau projectn ror Entoniag Finuandg Sweden and Norway. Oknana in aimini ror truuy nuntainaeue architectureg deniinini eneriyeefcient timeererrame euiudining de euopini cuntom moduuar nouutionn and popuuari7ini modern wooden architecture.

Pēteris Supe Latvia

Timo Leiviskä Finland

Timo Leiviskä studied architecture at the University of Oulu between 2000 and 2012 and at FAUP in Porto, Portugal between 2005 and 2006. While studying, he worked at local architecture ofces. .e founded his own ofce in 2000, after gaining a commission from students’ competition for one of two types of Art & Design Villas for a Wellness resort in Mikkeli, Eastern Finland. Leiviskä got an honorable mention of the WOOD AWARD / PUUPALKINTO from the villas in Mikkeli in 200 and was awarded the WOOD AWARD / PUUPALKINTO as a part of Lukkaroinen Architects’ team of Pudasjärvi Log Campus in 2016.

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Pēteris Supe is a certifed structural engineer at Rodentia, a structural engineering companl focusing on timber structures. He holds master’s degrees in Civil Engineering and Transportation Engineering from Riga Technical Universitl. His interest specifcalll in timber structures started with timber bridges during his bachelor studies in Transportation Engineering which continued in both master studies. Before he started working at Rodentia in 2016, he worked as a researcher at ( C on guidelines for timber bridge design. Since 2016, he has been involved as structural engineer in various projects with mass timber structures such as industrial buildings, sports venues, open-air stages, public buildings and bridges with emphasis on buildings with spans larger than 20 metres and curved elements.


Nicole Kerstin Berganski Alar Mihkel Just Urmet NKBAK Architects Estonia Germany

Juha Schroderus Finland

Juha

Schroderus

is

M.Sc.

(Technology),

Business

Development Manager at Stora Enso Wood Products Oy Ltd, Building Solutions. He has been working for Stora Enso

since

2015,

in

current

role

as

Business

Development Manager responsible for Finnish and Baltic markets

in

Glulam),

and

massive

timber

supporting

components

LVL-projects

(CLT,

globally.

LVL,

He

is

responsible for Wood City projects in Helsinki.

M ihkel Urmet is an architect more than 20 years of 15th 11:50 Educational buildings 1Êth April - 11:00 - ¸ire Designwith of I-joists in ¬all experience Assemblies ‒ specialised in wooden and timber

architecture with strong connection to Estonian woodhouse industry. Currently he is working on prefab Nicole Alar Just Kerstin is Berganski a professor has at gained Tallinn University experience of in modular solutions and concepts of her wooden high-rise renowned “Sustainable Technology ofces and a researcher for High-Rise several at RISE years. Research SheDesigned worked Institutes at buildings. Buildings and SANAA of Sweden. in Tokyo Dr.inJust forhas four regular years, courses the also atofLinnaeus Pritzker Constructed Timber (HiTimber )“ isstudio an international Prize winners University and promotes London KazuyoCity Sejima University. and Ryue He is Nishizawa. a reviewer for In program that timber construction education. 2007 goal several they scienti c journals, their in the owneldstudio ofis wood structures with The ofestablished the HiTimber project to NKBAK share best co-founder and re safety Sincestart then, they have practices ofAndreas different Krawczyk. countries and processes in realized projects in a wide range of frommanaging weekend universities of wider knowledge in scales, designing, He is thetohead of Estonian delegation in CEN TC 250 SC houses daycare centres and school buildings. In construction works and maintaining real-estate. 5 and member of TC250 - SC5.T4 project the team, drafting addition to utilizing classical materials, architects the generation of EN 1995-1-2. havenext discovered and developed the potential of timber construction as a central element in their work.

Peder Fynholm Denmark

Mr. Peder Fynholm is Vice Director of Center for Wood and Biomaterials of the Danish Technological Institute. Mr. Fynholm holds an M)c in engineering from the Technical University of Denmark with specialty in wood technology and mechanical properties. Mr. Fynholm is Technical Manager in Hori!on 2020 project Build-in-Wood. He is the network leader of the Nordic Network for Tall Wood Buildings, comprising more than 100 companies and other value chain stakeholders for tall wood buildings and managing several other projects related to using wood in construction. He has been at DTI since 2001 and works with consultancy and product development as well as certifcation and testing for customers nationally and internationally within the area of wood and biobased products. He has a very profound knowledge on market and legal requirements for products, especially wood related products for use in constructions. He has been involved in a number of national and international R&D and commercial projects within the area of multi-storey buildings of timber, Engineered Wood Products, wood-based panels, building physics, etc. Mr. Fynholm is also project manager for the Technical )ecretariat for roup of Notifed Bodies under CPR.

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2. Forum Wood Building Baltic 2021

Buildings for Education, Work and Sports | Much Untertrifaller

Buildings for Education, Work and Sports Much Untertrifaller, Dietrich | Untertrifaller Architekten, Austria

Summary Education buildings for children and work spaces for adults are places to spend most of the day and the atmosphere in the building is very important for wellbeing. Nowadays, it is not just important to build in timber but also the focus on quality of the architecture. Key words: timber, architecture, education buildings, sports, office building, CLT.

1. Secondary school and multipurpose hall in Klaus The secondary school and the hall were built in two phases at an interval of ten years. The spatial concept of the L-shaped building comprises three main functions: School, sports hall and library. After a record time of only 18 months, the school was completed in 2003. Constructed in timber, it is the first school in Austria to meet the strict passive house guidelines. Ten years later, a new multifunctional hall replaced the gym. Advanced planning strategies, such as compact organization of the program and prefabrication allowed for an accelerated schedule and optimized costs, while adhering to the high quality design and standards. The L-shaped building is slightly removed from the street and its wide south façade defines the forecourt. The two-story glazed connecting wing acoustically shields the classrooms and the playground from the street.

Fig. 1. The secondary school and the hall in Klaus, Austria (left). Interior of school (right).

2. College in Lamballe The College in Lamballe (Brittany, France), planned for 820 students, is mainly constructed in timber. It consists of two separate buildings: a long rectilinear parallelepiped rests on a gently curved base, to echo the site’s topography and fit in with the landscape. Fully glazed, the ground floor brings a sense of lightness to the building. It contains the entrance hall, the covered playground, the spaces for education, a multipurpose room, and the canteen. On the facades facing southeast and northwest, vertical and horizontal wooden sunshades control the amount of light entering the two floors of classrooms. They increase the thickness of the façade and their shape adds variety to the linear building. Inside, a three-story atrium gives natural light to the circulation area and the classrooms, creating a contrast with the compact nature of the building. The construction blends concrete on the ground floor to assure the sturdines s of the premises used by all, with prefabricated elements for the wooden boards (cross laminated timber) on the upper floors. The project respects the environment. Untreated local materials help the building fit in with its surroundings and also ensure the durability of the

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2. Forum Wood Building Baltic 2021

Buildings for Education, Work and Sports | Much Untertrifaller

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construction. Schools in France are basically all-day schools. In the morning, the pupils gather in the covered schoolyard and go collectively to their classrooms. Generous, bright access zones for communication and accommodation are very important. With the College in Lamballe, it was possible to strictly implement the highly standardized space program of French schools without restricting the generosity of the space. .

Fig. 2. The College in Lamballe, France (left). Interior of the College (right).

3. Wibeba Administration in Wieselburg The cubic administration building with its asymmetrically cut windows sets a landmark for the site of the hardwood sawmill Wibeba Holz in Wieselburg. With its eye-catching appearance, the small cube can assert itself against the large neighboring industrial buildings and at the same time blends harmoniously into its environment with loosely built up single-family houses. The massive exposed concrete core also forms the support for the prefabricated wood-concrete-composite ceiling elements. Most of the ventilation and electrical installations are located in the suspended ceiling made of silver fir. The inlaid mineral wool has a sound-absorbing effect and thus improves the acoustics in the building. The ceiling of the uppermost story consists of pure cross laminated timber. The outer walls are made of wood elements and covered with a ventilated, vertical oak formwork.

Fig. 3. The Wibeba Administration building in Wieselburg, Austria (left). Interior of the Administration (right).

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2. Forum Wood Building Baltic 2021 Challenges to use timber in load-bearing structures in Latvia | Kaspars Kurtiss

Challenges to use timber in loadbearing structures in Latvia Kaspars Kurtiss, M. Sc. Ing., Head of the Board of Latvian Association of Structural Engineers, Latvia Key words: fire safety of buildings, certified fire engineer, risk in timber during construction. In Latvia, the use of wooden structures in the construction of buildings has a long history. Nowadays, the application of wooden structures in load-bearing structures is taking on more and more serious revolutions. At the same time when the popularity of wooden structures is growing, it is important to be aware of the properties of wood as a material, design aspects and potential risks during the full life cycle of a building. At the first stage of the project, the customer's desire to choose a tree as the determining constructive concept of the building from the very beginning is of great importance. The determining criteria that dictate the use of wooden structures in construction at the design stage are fire safety standards. Their requirements severely limit the possibility of using open wooden structures in load-bearing wooden structures. The criteria set out in accordance with LBN 201-15 are as follows.

The requirements clearly indicate that for medium and large objects, the use of exposed wooden structures without additional protection measures is difficult. There is an alternative where regulatory derogations with the State Fire and Rescue Service of Latvia commission are possible, but this process is often subjective. Another disadvantage is that LBN 201-15 does not provide for the use of alternative calculation methods in fire design. The industry would need to seriously consider creating a certified fire engineer position in the future. An important aspect in the design of wooden structures is to consider both creep and shrinkage in structural calculations. These aspects strongly affect the calculations of wooden structures.

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2. Forum Wood Building Baltic 2021 Challenges to use timber in load-bearing structures in Latvia | Kaspars Kurtiss

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During the construction cycle, it is necessary to take into account significantly different conditions for the assembly of wooden structures, where external weather conditions and the protection of wooden structures during construction play an important role. Unprotected wooden structures have a high risk of being damaged during construction if they are not protected. The construction industry must take this aspect seriously, taking into account Latvia's climatic conditions on an annual basis.

Wood structures that are clad are high risks at high humidity. For upholstered wooden structures, it is not possible to determine their technical condition and to detect damage caused by moisture in a timely manner.

Summary -

It is important to start work on the improvement of the construction standard LBN 201-15 “Fire requirements for buildings”.

-

The industry needs to think about the position of a certified fire engineer in the near future.

-

The creep and shrinkage of wooden structures must be taken into account in the design process, especially in large structures.

-

An important aspect during the full construction cycle is the protection of wooden structures against the weather. This can cause significant problems for the further operation of wooden structures throughout the life cycle of the building.

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2. Forum Wood Building Baltic 2021 Pudasjärvi Log Campus| Timo Leiviskä

Pudasjärvi Log Campus Timo Leiviskä, Architect, Lukkaroinen Architects Ltd, Finland Key words: school campus, log structure, timber, wood building tradition

A Mass Timber School of a Log Structure The town of Pudasjärvi in Northern Finland began the project for a new school campus in 2012. The purpose was to replace several of town’s old school buildings that were in bad shape and located in areas that no longer served well the current population. Log structure was selected to reach a better indoor air quality and to utilize the know-how of local wood building industry in a large-scale construction. Pudasjärvi Log Campus opened in August 2016.

Figs. 1‒3. Exterior of school campus. Different functions of the school campus are divided in four building volumes. They enclose a schoolyard that opens towards south and is protected from the cold winds from the north. The structural walls are made of laminated log that create a strong sense of material and remind of the Nordic building tradition. The composition of openings and bright coloured accents give a playful and contemporary look to the facades. The roofs of the main hall and skylights are supported by glulam columns and beams. The skylight ‘lanterns’ provide the main spaces of the campus with daylight and distinct aesthetics as well as accentuate their position in the building volume.

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2. Forum Wood Building Baltic 2021 Pudasjärvi Log Campus| Timo Leiviskä

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Fig. 4‒8. Details of construction elements and log structure.

Acknowledgements Architects: Lukkaroinen Architects Ltd: Lead Architects: Pekka Lukkaroinen, Kristian Järvi, Timo Leiviskä, Hannu Tuomela Project location: Pudasjärvi, Finland Contractor: Lemminkäinen Talo Ltd, Supplier of the log frame: Kontiotuote Ltd Yard and landscape design: VSU maisema-arkkitehdit Ltd Structural design: Sweco Rakennetekniikka Ltd, Harri Moilanen Electrical design: Sweco Talotekniikka Ltd HVAC design: Plan-Air Ltd

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2. Forum Wood Building Baltic 2021 Education buildings | Nicole Kerstin Berganski

Education buildings in Frankfurt Nicole Kerstin Berganski, NKBAK, Germany . Key words: modular timber structure, classroom, school, architecture.

1. European School Frankfurt / Main The new building of the Pre-primary and Primary School extends the existing school building of the European School in Frankfurt / Main. The building was designed in a modular timber structure and yet it retains a high design level by arranging the spatial units around a spacious and open corridor in different directions. In addition to the classrooms the corridor functions a meeting place for the children and provides different views of the scenery. The vertical access to the building is via three staircases which are emphasized by spectacular colours and thus provide orientation for the children. A lift is integrated at the central staircase. All classrooms have a fully external glazed facade. As a result, a maximum natural illumination is achieved, and it allows for different views of the surroundings.

Fig. 1. European School in Frankfurt (left), Photo Thomas Mayer; The Classroom in the European School in Frankfurt (right), Photo Norman Radon. The building has 10 classrooms with adjoining rooms and integrated sanitary facilities for the pre-primary school and 7 classrooms and sanitary facilities for the primary school. Facilities for the teaching staff as well as work and multi-purpose rooms complete the space program of the school. On the ground floor there is a gym with a 12m span and a kitchen with attached dining room. The exterior walls are cladded with corrugated sheets of reflective aluminium. The windows and doors are wood-aluminium profiles. The windows on the south side have an external shading. The Kaufmann Bausysteme has dealt with the design requirements and has developed wooden modules based on the specified floor plan. The modules have spans of up to 9m as self-supporting structures. Each classroom is made up of 3 elements. The two edge elements have a longitudinal side wall of plywood board and a free-spanning beam. The middle element has longitudinally only two free-spanning beams. To realize this, wood beams out of 'Baubuche' (Laminated beech plywood) were used the first time due to their high strength especially for slender structures with large spans. During transport the beams were supported. Planning: December 2013 - July 2014 Construction: August 2014 - April 2015 footprint: 1,250 m² height: 9,95 m; floor area: 3,380 m²; floors: 3 storeys

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2. Forum Wood Building Baltic 2021 Education buildings | Nicole Kerstin Berganski

Integrated Riedberg 2.

Comprehensive

School

2

Frankfurt

The new building for the dual-track integrated comprehensive school was designed to provide a new home for the first two classes. An extension for further classes has already been realized. The concept needed to be implemented quickly and flexibly for the school year 2016/2017. The new building was therefore developed with a modular design. Two linear parallel forms are staggered and connected by a long central corridor. This shift infuses the corridors with natural light and establish a connection to the outside area. The two entrances to the building are also located here. The staggered arrangement also allowed for the extension to be added on one side. In addition to the classrooms, the corridors serve as places of encounter for the pupils and offer different views of the surroundings. Two stairways provide vertical access to the building. The stairways and corridors are highlighted in different colours, which also provides orientation in the building. All the classrooms and specialized rooms open up to the outdoor surroundings through large facade windows with external sun shading; the corridors are also outfitted with blinds. This maximizes the amount of natural light and gives children a generous and open connection to the surrounding outdoor area. The windows also provide natural ventilation. The facade cladding continues in front of these ventilation elements with openings as a subtle indication of the ventilation function. The outer walls are clad in raw Douglas fire boards, characterizing the new school building as an independent structure bridging the nearby green corridor and the new residential district. The window and door frames are made of wood profiles. The building modules are self-supporting constructions with spans of up to seven meters; a single classroom consists of three elements. planning: 2015–16 construction: 2016–17 footprint: 820 m² height: 9,5 m floor area: 2,460 m² floors: 3 storeys

Fig. 2. Integrated Comprehensive School in Frankfurt (left); The construction process of the School in Frankfurt (right), Photos Thomas Mayer.

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2. Forum Wood Building Baltic 2021 Wood-house architecture traditions and current practices in Estonia | Oksana Hetman

Wood-house architecture traditions and current practices in Estonia Oksana Hetman, M.A., Architect 1, Member 2; Mihkel Urmet, MSc., Member of Board 1, Member 2; 1 2

TEMPT architects, Estonia Estonian Woodhouse Association, Estonia

Summary TEMPT architects specialise in wooden constructions, prefabricated elements and modular architecture aiming to design CO2 neutral, energy efficient, ecological and comfortable buildings. Key words: timber construction, modular buildings, prefabricated buildings, wooden houses, modular housing.

1. Wood-house architecture traditions in Estonia Industrial manufacturing of wooden houses started to develop in Estonia in the 1950s when prefab homes from milled log and panels were produced in forest industries. Nowadays the manufacturing of wooden houses has developed into one of the key industries in Estonia with 170 enterprises. Today the various products produced by Estonian enterprises are: modular houses, element houses, garden houses and log houses from planed or round timber. In recent years Estonia became the biggest exporter of wooden houses in the EU based on the total turnover of wooden houses exported in a year (462 M€ production value in 2019). This was achieved through continuous cooperation between production factories, architects and organisations like Estonian Woodhouse Association and Estonian Wooden Houses Cluster.

2. Methods TEMPT architects aimed to develop an affordable modular housing concept which can be adapted for different Nordic countries. With off-site building methods and wood as main building material modern housing planned to be sustainable, comfortable and scalable. Together with TIMBECO Woodhouses it was possible to apply the abovementioned criteria into practice while developing a modular residential complex for Norwegian market.

3. Results and discussion This collaborative project is the first step towards a flexible modular system for wooden housing developments. With custom-designed modular buildings growing real estate developers can adjust planning and space needs at all stages throughout the design process. Moreover, using prefabricated production minimizes on-site impact on nature as well as unexpected costs compared to traditional on-site building. The first three residential buildings were designed and produced in 2020. Installation onsite on Lofoten islands went on during spring 2021.

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2. Forum Wood Building Baltic 2021 Wood-house architecture traditions and current practices in Estonia | Oksana Hetman

Fig. 1. 8-module house facade (left). Single-module studio flat plan (right).

Fig. 2. 10-module house facade (left). Double-module apartment plan (right). The project resulted in: ● ● ●

built and strengthened partnerships, collaboration among the participating companies and professionals; increased awareness, knowledge and skills of all participants (architects, engineers, producers and developers) in design, construction and management of sustainable modular timber buildings; increased public awareness about sustainable modular buildings designed and constructed in timber.

4. Conclusions Successfully built projects confirmed that from the design perspective it is essential to take wooden constructions’ specific requirements into account from a very early stage. Therefore, Estonian woodhouse producers have established close collaboration with architectural and engineering practices. This way, architectural practices work on broadening practical usage of wood as the main constructive material and develop concepts that can be later adapted into products.

5. Acknowledgements The projects were designed and developed in partnership with Estonian Woodhouse Association, woodhouse producer Timbeco and Bolig for Folket, local developers in Norway.

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2. Forum Wood Building Baltic 2021 Engineering challenges and solutions in the concert hall Mitava – open-air building with 57m timber span| Pēteris Supe

Engineering challenges and solutions in the concert hall Mitava – open-air building with 57 m timber span Pēteris Supe, Rodentia, Latvia

Summary Concert hall Mitava is an open-air concert hall with glued laminated timber (glulam) beams and steel columns. The clear span of up to 57 meters, open space and spherical geometry challenged the structural system and connections with varying loads and individual geometry. By using large number of custom made components and adopting technologies from other engineering disciplines, the building was completed in 2019. Key words: timber structures, connections, timber construction, architecture.

1. Introduction Located on a small island between two rivers in Jelgava, in Latvia, Mitava is an open-air concert hall with a capacity of up to 1200 seats. The Pasta island is created as a recreational zone for the residents of the city with playgrounds, a beach and a timber open-air ice-skating rink. The structure of the roof was built over an existing amphitheatre to shelter visitors from wind gusts, rain and also hot summer sun. The architecture is inspired by a shell washed upon the shore of the river, as explained by the architect of the building – Vents Grietēns (Projektu birojs Grietēns un Kagainis). We had a close collaboration on all the technical details to achieve the desired aesthetics of elements and connections. The total dimensions of the structure are 60.7 metres by 60.6 metres with a height of 15 metres. The load bearing structures of the building consist of approximately 510 m3 of timber, 77 tons of steel and 11 600 connectors.

Fig. 1-2. Concert hall Mitava.

2. Structural system and design The asymmetrical roof structure consists of curved glulam beams with 4 round steel ties for each beam and a span up to 57 meters. The curved beams are supported by elliptical glulam ring beams that are continuous on both sides of the building and connect at ground level. Glulam purlins and steel tension rods are used to provide the stability of roof structure. The whole building stability is provided by the ring beam and steel columns that support the ring beam.

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2. Forum Wood Building Baltic 2021 Engineering challenges and solutions in the concert hall Mitava – open-air building with 57m timber span| Pēteris Supe

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The structure is covered by a tensile membrane. After the design of tensile membrane (Canobbio Textile Engineering), the top glulam purlins had to be moved downwards, as the membrane can have considerable deflections from snow load. The horizontal forces from tensile membrane also had to be taken into account for the design of glulam beams. Combination of light materials and the open location of the building results in significant uplift forces from the wind load. Thus, most of the elements and connections have varying direction internal forces. This is also the reason why the ring beam could not be hanged in the cables coming from the steel pylons and additional columns were necessary. Therefore, the cables from pylon are architectural.

3. Connections Connections are made with custom steel parts, steel dowels, bolts and fully threaded timber screws. Most of the steel parts for connections were verified individually in FEM software. The bending moment resisting connections of glulam members are made with fully threaded timber screws at a 45 degree angle for higher stiffness of the connection. During the construction phase, a special electric screwdriver was used for the fully threaded timber screws. This screwdriver is usually used in machine industry and controls the torque by a computer, thus preventing the overtightening of screws against a steel plate. The connection between the ring beam and steel columns were designed as semi-rigid. But due to the geometry of the building, the forces in the shortest columns and pylons were too large to maintain the desired profiles and dimensions of members and connections. A hinged connection was necessary to allow the rotation along all axis of the connection, which couldn’t be solved by usual means. The idea of custom made spherical bearings was inspired by bridge industry in which this solution is seen more often.

4. Building systems The structural design of this building included the design of acoustic shields, acoustic panels, wind mesh and rainwater collection system. The rain gutter is mounted on the ring beam and made of open profile bent of structural steel. The gutter ends and downspouts are made of closed steel profile. To reduce the wind inside the concert hall, special wind mesh is used between the steel columns The placement, size and materials of the acoustic panels and shields were designed according to the acoustics project. This included triangular plywood shields on three sides of the building to reflect and disperse the sound and panels between curved beams made from perforated plywood and mineral wool to absorb the sound. Additionally, rounded elements were added to the interior edges of the curved beams and ring beam. As a result, the building has excellent acoustics already praised by people from the industry.

5. Acknowledgements We thank the following companies for taking part in the design of this building: Projektu birojs Grietēns un Kagainis (architecture), IKTK (production of glulam and acoustic system), Canobbio Textile Engineering (design and production of roof membrane), Mitau Steel (production of steel structures), Igate Būve (general contractor).

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2. Forum Wood Building Baltic 2021

Why was Helsinki building a Wood City?| Juha Schroderus

Why was Helsinki building a Wood City? Juha Schroderus, Business Development Manager, Stora Enso Wood Products Oy Ltd, Finland Key words: architecture, offsite construction, design, LVL.

Wood City, first of its kind in Finland Wood City is a landmark for massive timber frame building in Finland. The first multistorey buildings made from LVL, CLT, and glulam of this size, but definitely not the last. It is a new district of Helsinki in timber and quite literally taking wooden construction in the country’s capital to new heights. The urban block with a ground space of 34 000 m² consists of housing, hotel, parking and office premises. The building site is located next to the harsh waterfront in developing Jätkäsaari area, close to Helsinki city centre. The Wood City housing buildings, fully built with LVL, were completed in 2018. The office building was completed in the end of 2020, and the hotel building, finalizing the last part of the city block, will be completed in the next few years. The office building is custom designed and built for the Finnish mobile game developer company SUPERCELL headquarters. Building with wood was the natural choice for the owner, having environmental values as one of their key drivers. With GFA of 12 800 m² and 8 storeys, it is by now the tallest and largest wooden office building in Finland and Northern Europe.

Fig. 1. Rendering of Wood City city block in Helsinki.

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2. Forum Wood Building Baltic 2021

Why was Helsinki building a Wood City?| Juha Schroderus

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Fig. 2. Wood City Office.

Fig. 3. Wood City residential buildings.

Fig. 4. Wood City Office lobby’s CLT-features.

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2. Forum Wood Building Baltic 2021 Building Regulation | Peder Fynholm

Building Regulations. Why timber is better than the building law thinks it is Peder Fynholm, Vice Director, M. Sc., Lead auditor, Danish Technological Institute, project “Build in Wood” representative, Denmark

Summary This is a comparative analysis of the member state building regulations applying to multistorey wood buildings. The results provide a point of reference for several Build-in-Wood activities. Along with a general overview of the member state building regulations, a more specific view on area specific legislation is provided for the following areas: fire safety, acoustics, and energy performance. A spreadsheet file for each area has been created in order to collect information and provide an overview of legislation requirements. The general regulations overview contains information about where the requirements are found, which standards or guidelines relate to the requirements, and contains information about the formulation and organization of each building regulation. The specific spreadsheets contain detailed requirements for specific topics allowing comparison of the different member state regulations. Key words: regulation, timber construction, buildings, multi-storey

1. Introduction The comparative analysis of the member state building regulations seeks to identify technical requirements and their variation. Collected requirements are gathered in spreadsheets. Information is collected at two levels: 1) overall member state regulations overview and 2) specific legislation for selected areas of importance for multi-storey wood buildings. Data is presented as datasheets which are available from the Build-in-Wood community at Zenodo.org through the following URL: https://zenodo.org/communities/build-inwood/?page=1&size=20. Links to specific datasets are provided throughout this deliverable. The data is collected in spreadsheets and presented in easy-to-read graphs / tables. An overview of member state regulations where links to updated member state requirements could be found, e.g. national annexes and guidelines used to fulfil member state requirements is presented in the following dataset: Member State regulations overview. Specific legislation for the selected areas of importance for multistorey wood buildings (focus on loadbearing structure) have been collected and presented in the following datasets: Fire, Acoustics, Energy and indoor environment The spreadsheets are subject to periodic updates. The newest versions can be found on Zenodo. Other areas of interest for Build-in-Wood, e.g. durability, sustainability, or partial coefficients, may be collected in spreadsheets according to the need. Identification and understanding of the member state legislation and regulations of multi-storey wood construction provide an essential reference point for many Build-in-Wood activities, since Build-in-Wood developments need to be relevant for the wider European area. For the specific legislation for selected areas of importance, special focus has been on the member states of the Build-in-Wood Early Adopter Cities. The strictest requirements amongst the member states’ building regulations are identified and further a realistic requirement level is determined which enables the Build-in-Wood design guide to comply to the majority of member state legislations.

2. Methods Data collection was done as a literature study and exchange of knowledge between consortium partners, industry, RTOs and Universities. DTI is currently acting as a technical secretariat for the group of notified bodies under the Construction Product

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Regulation, and input from that work is also included. A literature review was conducted to identify and understand how the different building regulations are structured. The findings from the literature review have been the basis for further data collection.

3. Results and discussion The overview collects guidelines, pre-accepted solutions, and standards related to the member state building regulations. Commonly, standards are mandatory, and guidelines are non-mandatory, however, guidelines and pre-accepted solutions are often perceived as mandatory by the practitioners. Therefore, a distinction between mandatory and nonmandatory requirements was made. Build-in-Wood works with stakeholder involvement and implementation of wood building strategies in each of six early adopter cities (Fig. 1). Therefore, the initial focus of the data collection was to cover Austria, Denmark, England, Italy, Norway, and Romania. As some of these countries have regulations set by regional or even local authorities, regional regulations were also included. In addition to the early adopter cities, data was collected from the member states represented in the Build-in-Wood consortium. The consortium covers the following member state nations: Austria, Belgium, Denmark, England, Germany. The collection of building regulations is centred around the seven basic requirements for construction works which are laid down by the Construction Product Regulation, as all member state legislations are deemed to cover these topics. The collected data in the spreadsheet on Zenodo (URL https://zenodo.org/record/4008973#.X0zNftZxeUk) can be viewed in a popup window when the ‘Output’ button is clicked. The popup window gives an overview of the collected data and enables search of the member state requirements applying to a given topic. Data is sorted by country, and the spreadsheet allows filtering of input data by requirement topic (Structural Design, Fire, Building physics, Spaces and accessibility, Acoustics, Energy Consumption, Sustainability, Administrative provisions, Other). If a link to the requirement source exists in the spreadsheet, the popup window sorts the links in a column next to the requirement and leads the user to the source if the ‘Link’ text is clicked. Fire safety ‒ the dataset on fire resistance of loadbearing structures is available at the following URL: https://zenodo.org/record/4008995#.X0zM5tZxeUk. Acoustics ‒ the dataset on acoustics is available at the following URL: https://zenodo.org/record/4009003#.X0zNCtZxeUk. It gathers acoustic requirements regarding airborne and impact noise between residential units. Energy and indoor environment requirements regarding energy and indoor environment of the different member states is available at the following URL: https://zenodo.org/record/4009005#.X0zNMtZxeUk.

4. Conclusions This deliverable has analysed the member states building regulations applicable for multistorey wood buildings. The organisation and formulation of the member states regulations were found to differ, hence spreadsheets which can accommodate the difference have been created on two levels of the regulations: on an overall level that compares the formulation, organization, and accessibility of the member state building regulations and on a detailed level of identified areas of importance for multi-storey wood buildings. These areas were identified as: fire safety requirements, acoustic requirements, and requirements to energy performance and indoor environment. The comparative analyses are presented in spreadsheets made publicly available at Zenodo and will be updated throughout the project.

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FWBB2021: 2nd Forum Wood Building Baltic HiTimber project – Future of wooden highrises Regulation | Mihkel Urmet

HiTimber Project – Future of Wooden Highrises Mihkel Urmet, MSc., Estonian Woodhouse Association, TEMPT Architects, Estonia

Summary Estonian Woodhouse Association (EWA) in co-operation with Tallinn University of Applied Sciences participate in an international program “Sustainable High-Rise Buildings Designed and Constructed in Timber” (HiTimber) that promotes timber construction education. The goal of the HiTimber project is to share best practices of different countries and start processes in universities of wider knowledge in designing, managing construction works and maintaining real-estate. Key words: educational project, timber construction, timber high-rise buildings, study module.

1. Introduction 1.1. Project background The United Nations (UN) projects the world population to be 9.8 billion by 2050 and 68 % of them will be urban – that is about 2.5 billion new people in cities. These people need homes and we cannot just make cities bigger – we need to go higher. The race for timber high-rise buildings has started as more thought is put into how to do it sustainably. Wood is renewable, absorbs carbon dioxide (CO2), has excellent insulation properties, light weight and is well processable. Wood is constantly more and more used in construction industry, yet education regarding building high-rise buildings of wood is still moderate. The goal of the three-year co-operation project is to work out a new study module to help teach timber construction at universities. HiTimber project was written by VIA University College (Denmark) in co-operation with several partners in order to fulfil future needs for higher education considering innovation, sustainability, international and cross-university approaches.

2. Outputs and project activities Each Partner will contribute to all intellectual outputs: international study; new study module; book; assignment books; academic publications. During the project, participants will visit leading sustainable construction sector companies ‒ from architects to woodhouse manufactures in Denmark, Lithuania, Portugal, United Kingdom and Estonia and will learn from the experiences of professionals to get the knowhow. This will lead to new innovative skills not only for students but for teachers as well. Also, the project will give the students the possibility to take part in short practical placements in relevant regional and national timber construction companies. The project was opened by the partners’ meeting in Tallinn at the end of 2017. Next meeting of the project team took place in Denmark at the beginning of 2018, where an intensive project for students was discussed. A workshop for the students of universities that participate in the program was held in Great Britain in April 2018. The first two-week study period gathered 30 students from Portugal, Lithuania, Denmark, Great Britain and Estonia in Southampton. The students were introduced to the specifics of designing timber structures, divided into international groups and were given a teamwork task to re-design an existing reinforced concrete building into a timber-structure building in a manner that

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would follow all existing construction requirements. In addition to the task, the students participated in lectures about timber structures, the architecture of wooden high-rise were gided in specific questions during their teamwork process.

3. Results of the project Sharing of innovative ideas, regional and professional experiences and development of a new innovative trans-disciplinary, transnational course (module) will lead to a higher quality of teaching and cooperation within EU. The basis of the project and the development of the new course or elective element will be formed around the education methodology “project based learning” and “learning by doing”. That is a new concept for the participating universities that needs to be developed. This will lead to the transfer of innovative education and trans-national practices, where creativity, critical thinking, problem solving, innovation, communication and flexibility skills will be obtained. 

Built and strengthened partnerships, collaboration among the participating institutions.

Increased awareness, knowledge and skills of all target groups (students, teachers, enterprises) in design, construction and management of sustainable high-rise timber buildings.

International study on best practices and knowledge gaps for construction of sustainable high-rise timber buildings.

Innovative teaching competences and improved quality of studies: o

new BSc/BA trans-disciplinary study module “Sustainable High-Rise Buildings Designed and Constructed in Timber”;

o

book “Sustainable High-Rise Buildings Designed and Constructed in Timber”;

o

Assignment books for project-based learning.

Innovative knowledge and increased employment opportunities of graduates.

Increased public awareness about sustainable high-rise buildings designed and constructed in timber.

4. Project partners Other partners of the project include: Southampton Solent University, Tallinn University of Applied Sciences, Vilnius Gediminas Technical University, Universidade de Lisboa, Charted Institute of Architectural Technologies (CIAT), Charted Institute of Builders (CAOB), Denmark Constructor Union (KF union), TISEM, LDA (TISEM), serQ ‒ Centro de Inovação e Competências da Floresta ‒ Associação, Sonae Group and Amorim Group, Lithuanian Association of Timber Houses Producers, Lithuanian Builders Association and Lithuanian Real Estate Development Association, Study and Consulting Center (SCC).

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WOOD IN ARCHITECTURE. INNOVATIONS AND CONSTRUCTION SOLUTIONS Andrea Frangi, Switzerland Edvīns Grants, Latvia Alar Just, Estonia Karina Buka-Vaivade, Latvia Kārlis Pugovičs, Latvia Aivars Vilguts, Norway Anatolijs Borodiņecs, Latvia Kristo Kalbe, Estonia Renee Puusepp, Estonia

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Andrea Frangi

Alar Just Estonia

Vice chairman of Eurocode 5, ETH, Zürich, Switzerland

Andrea Frangi is Professor for Timber Structures at the Institute

of

Structural

Engineering at

ETH

Zurich

since

2010. He received his diploma in civil engineering in 1995 and a Ph.D. in technical science in 2001, both from the ETH.

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engineering

as

proGect

company

Vancouver

leader

“Read

from

in

Jones

2001

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structural

Christoffersen” 2001

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and

in

“Marchand+Partner” in Zürich from 2004 to 2009. He is mainly interested in timber construction and fre safety engineering.

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(SIA)

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in

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2020

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MAS

ETH

of

president

Civil of

Fire

Zurich.

safety He

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the

Swiss

a

and

Code

Committee for Timber Structures. He is vice-chairman of TC250 SC5 (Eurocode 5, Timber Structures), chairman of TC250

SC5

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WG4

Group

(Horizontal

(Eurocode

Fire)

Group

and

Fire).

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5,

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member is

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member

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Switzerland, the International Association for Fire Safety Science Bridge

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International

Engineering

and

president

Association

(IABSE). of

the

He

Swiss

for

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Wood

Innovation %etwork (S-WI%).

Alar Just is a Professor at Tallinn University of Technology and a researcher at RISE Research Institutes of Sweden. He completed his dissertation on fre resistance of timber frame assemblies in 2010. Dr. Just has been working as a chief engineer at the structural design ofce for 15 years where he led the design of many timber buildings and bridges. From 2010, he works as a researcher at RISE Research Institutes of Sweden where his research is related to fre resistance of timber structures. He has conducted more than 200 fre tests. Dr. Just is a Professor of Structural Engineering at Tallinn University of Technology. He is currently supervising 3 PhD students in the feld of fre resistance of timber structures. Besides home university he gives regular courses at Linneaus University and London City University. Dr. Just is a reviewer of several scientifc journals, he is in the scientifc board of conferencess Structures in Fire, Wood Building Forum, Wood and Fire Safety. Alar Just was a core group member of C ST Action FP1404 Fire safe use of bio-based building products”. He is head of Estonian delegation in CEN TC 250 SC 5 and member of TC250 - SC5.T4 project team, drafting the ne t generation of EN 1 5-1-2.

Edvins Grants Latvia

Kristo Kalbe Estoni

Edvīns Grants is an engineer of timber constructions with a degree and qualifcation in civil engineering and more than

ten

quality

years

of

work

management

constructions.

of

Currently

experience

in

production

production

of

timber

he

works

as

fre

and

building

protection

engineer at the Forest and Wood Products Research and Development Institute and as civil engineer at “Rodentia”.

Karlis Pugovics Latvia

Kārlis Pugovičs is a researcher in Forest and Wood Products Research and Developement institute. He is a guest lecturer in the Department of Wood Processing of Forest Faculty of Latvia University of Life Sciences and Technologies. He is building and breaking stuff for living. He is a young researcher with interest in applied research that can be brought to manufacturing, new products and timber.

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risto lbe is PeD c niii te ni n exdert in tee nZE rese rce groud t l llece. He e s exderience in moisture s fetyh builiing deysicsh energy derform nce of builiingsh d ssise eouses ni l bor tory exderiments ni ieli stuiies. efore joining l lleceh risto worrei in tee dref bric tei timber builiing iniustry s droject le i ni ceief tecenologic l ofcer ni w s insolsei wite tee irst intern tion lly certiiei d ssise eouses in Estoni . His dresious exderience lso incluies rese rce t tee nisersity of l rtu ni ieselodment of iniustri l construction systems.


Aivars Vilguts Norway

Aivars Vilguts graduated from Riga Technical University in 2014 and receiveda master's degree in structural engineering. He has also worked as a structural engineer specializing in timber building design of timber frame buildings. From 2016, Aivars Vilguts was a Ph.D. student at the Norwegian University of Science and Technology and participated in the pro ect OODSO , and in 2021 successfully defended his Thesis " oment-resisting timber frames with semi-rigid connections". At the time of his Ph.D. studies, he developed two types of moment-resisting beam-to-column connections based on screwed-in threaded rods and steel coupling parts with su cient rotational stiffness and moment capacity. Also, his Ph.D. work showed, that it is possible to building mid-and high-rise timber buildings with moment-resisting frames by use of the developed connections. Currently he is a structural engineer in the company Oslotre AS, Norway with a specialization in timber engineering and parametric design.

Anatolijs Borodiņecs Latvia

Dr.

sc.

ing.

Anatolijs

Borodinecs

since

2013

is

a

Professor with the Institute of Heat, Gas and Water Technology

of

Riga

Technical

University.

His

main

research areas are building energy eeciency and building physics. The major recently elaborated projects are deep nZEB modular retroftting and energy eecient solutions for unclassifed buildings. He recently participated in INTERREG, FP7 projects as well as in HORIZON2020.  Anatolijs has gained experience at Indoor Environment Center, Department of Architectural Engineering at the Pennsylvania

State

University

under

the

Fulbright

scholarship. Since 2013, he has been reviewing articles for ELSEVIER journals and several reputable conferences. Since 2015, he holds a REHVA FELLOW status. He is also a

member

of

the

Board

of

Latvian

Association

of

Heating, Ventilation and Air-conditioning Engineers and a member of ASHRAE. Under his supervision frst full scale modular retrofring project using wooden frame carcass was implemented within the scope of H2020 project. As energy auditor he was in charge for several projects on solar energy systems design and installations. He has 72

Renee Puusepp Estonia

Renee Puusepp is a construction technology innovator and the lead architect of 369 Pattern Building industrial construction system. He is a founder and CEO of Creatomus Solutions ‒ an Estonian construction technology start-up working towards mass-customisation of housing. Renee has gained extensive expierience from his London-based company Slider Technologies that has been developing technologies for the construction sector since 200 . As a senior researcher in the Department of Architecture at the Estonian Academy of Arts, he4leads product development research of new modular housing concepts.4His team at Creatomus helps off-site manufacturers, residential developers and architects to design and sell modular houses. 3 He has started a number of successful business ventures and worked on several innovative property technology solutions. Having nished his formal training and started professional career as an architect in Estonia, he completed a Sc in Computing and Design as well as a PhD in Architecture at the "niversity of East London. In 2011, he was awarded a doctorate degree for the Thesis investigating agent based techni ues for advanced architectural modelling. 3

SCOPUS indexed publications,  his SCOPUS h-index is and Google scholar h-index is 12.

Karina Buka-Vaivade Latvia

Karina

Buka-Vaivaee,

M.

sc.

ing.,

PhD

stueent,

is

a

researcher with the Institute on Structural Engineering ane

Reconstruction

research

cross-laminatee concrete,

on

eirections timber,

Riga are

Technical

behaviour

timber-concrete

University.

timber on

fbre

com osite

He

structures, reinnorcee structures,

timber-concrete connections

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2. Forum Wood Building Baltic 2021 Eurocode 5 Revision – Fire design of timber structures| Andrea Frangi

Eurocode 5 revision – fire design of timber structures Andrea Frangi, Prof. Dr. 1; Alar Just, Prof. Dr. 2; Jouni Hakkarainen 3; Joachim Schmid, Dr. 1; Norman Werther, Dr. 4 1 2 3 4

ETH Zurich, Institute of Structural Engineering, Switzerland Tallinn University of Technology (TalTech), Estonia Eurofins Expert Services, Espoo, Finland Technical University of Munich, Germany

Summary The paper presents the current state of work revision of Eurocode 5, EN 1995-1-2 (Fire design of timber structures) and underlines some highlights of the new EN 1995-1-2. Key words: Eurocode 5, structures, timber, fire resistance, fire design.

1.

Introduction

The European Commission has a strong interest in further development of the Eurocodes to achieve a further harmonisation of design rules in Europe, and the revision process of all Eurocodes has started in 2015. The second generation of the Eurocodes is expected to be published starting from 2023. The main objectives of the revision are the improvement of the ease-of-use of the Eurocodes for practical users, the reduction of national determined parameters and further harmonisation and inclusion of state-of-the-art. After an intensive discussion within CEN/TC 250 it was defined that the Eurocodes are addressed to competent civil, structural and geotechnical engineers, typically qualified professionals able to work independently in relevant fields.

2.

Current state of work revision of EN 1995-1-2

The drafting work of the new EN 1995-1-2 is performed by a project team (PT), which consists of the five authors of this paper. Basis for the drafting work are extensive documents, reports and publications with the update state-of-the-art with regard to the structural fire behaviour and fire design of timber structures, e.g. the European Technical Guideline “Fire safety in timber buildings” [1] or the reports prepared in the frame of the recently concluded COST Action FP1404 [2-4]. The PT started its work on June 2018 and regularly reports to the Working Group WG4 of CEN/TC250/SC5 which is responsible for the revision of EN 1995-1-2. During the last 3 years, the PT prepared three drafts which were reviewed by the WG4 and commented by the national standardisation bodies. The first draft (May 2019, 75 pages) received 265 comments, the second draft (May 2020, 134 pages) 624 comments and the third draft (November 2020, 138 pages) 364 comments. The final draft of EN 1995-1-2 will be submitted at the end of April 2021. Based on the principles set up for the revision and the results of the systematic review of the current EN 1995-1-2, it was possible to identify the need for the improvement and extension of the fire design rules for the second generation of EN 1995-1-2. The following list gives some highlights of the new EN 1995-1-2: • Charring has extensively been dealt, and the current model (in the future renamed as the European charring model) has been generalised considering the different phases of protection and the different modification factors for charring in a more systematic way. Further, the charring model clearly distinguishes two cases (bond line integrity maintained or not maintained during the fire exposure). Supplementary guidance for the assessment of the bond line integrity in fire has been included in an annex. The failure times (defined as fall-off times) of different panels, including gypsum plasterboard Types A and F and gypsum fibreboards are given with simplified equations

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2. Forum Wood Building Baltic 2021 Eurocode 5 Revision – Fire design of timber structures | Andrea Frangi

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based on a large data base of fire tests. Further, for the fire design it is possible to use failure times based on full-scale fire tests performed according to EN 13381-7. d ǡ

Key

Ͷ

101

Encapsulated phase (Phase 0)

121

Protected charring phase (Phase 2)

131

Post-protected charring phase (Phase 3)

141

Consolidated charring phase (Phase 4)

ʹͷ

dchar,n t

Ͳ

t

ʹ

t ǡ

͵

t

t

Notional charring depth Time

tch

Start time of charring

tf,pr

Failure time of the fire protection system

ta

Consolidation time

Fig. 1. Phases for initially protected sides of timber members according to the European charring model when the bond line integrity is maintained during the fire exposure.

• As simplified design method only the current Reduced Cross-section Method (in the future renamed as Effective Cross-section Method) is given. The current Reduced Properties Method has been deleted. The Effective Cross-section Method has extensively been revised and its use extended to all common structural timber members, including cross-laminated timber panel (CLT) and timber-concretecomposite elements (TCC). • The current Annexes C (Timber frame assemblies with filled cavities) and D (Timber frame assemblies with void cavities) have extensively been improved and moved to the main part of EN 1995-1-2. The revised content is normative. The design model for timber frame assemblies with filled cavities is based on the Effective Cross-section Method and allows considering the performance of different types of insulation (mineral wool, cellulose, wood fibre, etc.). The performance of the insulation can be evaluated with small-scale fire tests and assessed in 3 different protection levels. • The current Annex E (Component additive method for the verification of the separating function) has extensively been improved and moved to the main part of the EN 19951-2. The revised content is normative and the design method has been extended to 120 minutes fire resistance. • Improved rules for the fire design of connections up to 120 minutes fire resistance are given based on extensive experimental and numerical analysis. Further, tabulated design data have been included allowing a simple fire design of connections. • Effective thermal and mechanical properties for timber, gypsum and insulation have been included for advanced calculation models based on FE-analysis. • For the design of timber structures exposed to physically based design fires improved rules and design methods have been developed and given in an annex. It is expected that the second generation of EN 1995-1-2 will fill most gaps of the current EN 1995-1-2 and will allow a safe and economic design of timber structures in fire.

3. [1] [2] [3] [4]

References Fire safety in timber buildings. (2010) Technical Guideline for Europe. SP Technical research Institute of Sweden, Wood Technology. SP Report 2010:19. Stockholm, Sweden. Just A., Schmid, J. (eds) (2018), Improved fire design models for Timber Frame Assemblies – Guidance document, COST Action FP1404, Zürich, Switzerland. Klippel, M., Just, A. (eds) (2018), Guidance on Fire design of CLT including best practice, COST Action FP1404, Zürich, Switzerland. Brandon, D., Kagiya, K., Hakkarainen, T. (2018), Performance based design for mass timber structures in fire – a design example, COST Action FP1404, Zürich, Switzerland.

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2. Forum Wood Building Baltic 2021 Climate protective buildings – driver for evolution of Latvian fire regulation | Edvīns Grants

Climate neutral economy – driver for evolution of Latvian fire regulations Edvīns Grants, Researcher, Forest and Wood Products Research and Development Institute, Latvia

Summary Climate protection and sustainability trends are a driver for architects and designers to use wood and wood-based construction products because they fit in future climate neutral world. However, regulatory frameworks need upgrades and Latvia is no exception. Performance-based fire engineering methods might aid to maintain material neutrality and support use of wood in sustainable future buildings at the same time granting the required safety levels. Key words: fire engineering, performance-based design, prescriptive fire design.

1. Introduction At the end of 2018, European Commission published its strategy to become climate neutral Europe till 2050 [1]. One year before that the Federal Republic of Germany has published and announced “Charter for wood 2.0” [2] which sets milestones towards national development which is aligned to common European goal on the basis of three main principles: -

Climate protection by endorsing use of sustainable technologies such as use of renewable resources and improvement of resource management.

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Improvement of added value by endorsing further processing of resources and improvement of industrial capacity.

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Resource efficiency by prolonging the working life of resources used to produce items.

Achievement of all three principal goals are related with smart management, use and recirculation of wood resources and products at the same time allowing research programs to improve other materials and products that might find a way how to become sustainable. Therefore, it is so important to continuously develop and improve national regulatory framework for buildings and construction works by implementing improved design practices which shape building industries of other nations and maybe one day other countries will have something to learn from us.

2. Case study: Pre-school education facility No. 7 in Salaspils In 2020 construction work started on a pre-school education building in the growing settlement of Salaspils, not far from the capital city of Latvia, Riga. With the support of architectural design company MADE Ltd and the Latvian Wood Construction Cluster nationally uncommon fire protection engineering practices were used to design a twostorey kindergarten made of massive wood-based construction products.

2.1. Regulatory barriers for wood and wood-based structures in buildings Architecture design company MADE Ltd headed by architect Miķelis Putrams and local municipality of Salaspils driven by sustainable building visions were determined to design and build a preschool educational building made of sustainable and ecological timber structures. During the design process it was discovered that there are fire safety

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prescriptive regulatory restrictions [3] that do not allow use of combustible materials as structural elements for proposed design. According to Latvian National Building Law [4] the non-conforming design can be accepted if it can be proved that the alternative solution is equal or better than the prescribed one.

2.2. Implementation of ASET/RSET design principle Performance-based fire engineering method for assessment of evacuation process were examined to verify the design from the egress point of view in order to evaluate the design options of the two-storey kindergarten where massive timber construction products as structural elements are used. The design process was performed using Technical Specification of Nordic countries INSTA TS 950 [5] and ISO technical specification ISO/TS 29761 [6], Technical report ISO/TR 16738 [7] with an assistance of SFPE Handbook of fire protection engineering, 5th edition [8], and computer modelling software “Thunderhead engineering Pathfinder”. Evacuation scenarios were established for all seasons of the year using evacuation data form previously done studies [9] about evacuation strategies in pre-school education facilities for children of age from 1.5 to 7 years.

3. Results and discussion The design process resulted in clear evacuation organization plan and building design elements such as smoke protected egress routs with at least one alternative route for every group of children and four additional staircases for everyday use in order to speed up evacuation process using already known exits, that supports the established egress concept. Estimated required safe escape time was 23 minutes for 344 occupants of the building. The design process and results were demonstrated to the National Fire Service for approval before implementation and were confirmed.

Fig. 1. Salaspils preschool education institution No.7 – 3D model.

4. Conclusions Today’s performance-based fire protection engineering methods are necessary for further development of sustainable building trends. It is reasonable to implement performance-based fire engineering methods in regulatory framework besides the prescriptive rules in order to extend the design options and give common ground for building designers, fire protection engineers and controlling authorities.

5. Acknowledgements This study was supported by Forest Sector Competence Centre of Latvia within framework of research project – 1.2.1.1/18/A/004 – P1, The Latvian Wood Construction Cluster and

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2. Forum Wood Building Baltic 2021 Fire Design of I-joists in Wall Assemblies | Katrin Nele Mäger

Fire design of I-joists in wall assemblies Katrin Nele Mäger1; Alar Just1,2 1 2

Tallinn University of Technology, Estonia RISE Research Institutes of Sweden

Summary Wooden I-joists are factory-made lightweight engineered wood products used as loadbearing elements in timber frame assemblies. I-joists are optimised for material use. Fire resistance of such engineered wood products is a complex matter. This study covers investigations on wall structures made of I-joists. A design procedure is proposed. Key words: fire design, charring, load-bearing capacity, wooden I-joists, buckling.

1. Introduction Wooden I-joists are used in timber frame floor and wall assemblies. I-joists are engineered wood products that consist of flanges (made of sawn wood, LVL or glulam) and a web (made of a wood-based board) (see Fig. 1 (a)). Due to the small sizes the fire design of these structures needs more complicated approach compared to solid wood structures with rectangular cross-sections.

(a) Lower flange and web

(b) Charring phases Fig. 1. Design model for I-joist.

The earlier proposed design models of König (2006) and Schmid et al. (2011) have been thoroughly investigated, and multiple limitations were identified. The improved design model by Mäger (2019, 2020) takes into account the effect of charring considering 4 different charring phases behind the protection and after failure of protection: no charring occurs behind the protection (Phase 0); slow charring behind the cladding (Phase 2); after the failure of the claddings the structural member and cavity insulation will be directly exposed to fire and the charring rate will rapidly increase for a short time (Phase 3); after consolidation time ta the consolidated charring (Phase 4) is considered. Charring on the lateral sides of flanges is dependent on the cavity insulation materials. Additionally, the effect of heating behind the char layer is taken into account by decreasing the cross-section by the zero-strength layer d0 (see Fig. 1(a)). The effective cross-section with dimensions bef and hef is assumed to have no strength reduction.

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2. Experimental research Fire design model of I-joists is based on extensive experimental research. In addition to previous research a total of 20 new horizontal model-scale tests (MST) have been performed with specimens with I-joists and various insulation materials in the model scale furnaces at RISE. The fire exposed side was initially protected by gypsum plasterboards. The unexposed side was covered by a wood-based board. All tested cross-sections had a height of 200 mm or 220 mm. Two series of compression tests at ambient conditions were carried out at RISE in Skelleftea in 2019 and 2020 to investigate the buckling behaviour of I-joists with various flange sizes, eccentricity and bracings; cross-section heights 200 mm to 500 mm.

3. Results and discussion Based on this research and analysis the design model for wall assemblies with I-joists was proposed. 3 different cases for buckling in the walls plane are considered: (1) both flanges are braced;(2) both flanges are not braced; (3) the flange on the fire unexposed side is braced while the flange on fire exposed side is not (see Fig. 2). For (1) and (2) the buckling analysis is made according to EN 1995-1-1 taking the effective moment of inertia into account. For (3) the buckling of the unbraced flange is considered taking into account the stiffness of the web. The loads are distributed between flanges according to the stiffness of flanges and taking into account the eccentricity. (b) 4 3 z

y

hf,ef

y

1

bf,ef

2

(a)

Key: 1234-

Fire exposed flange of the I-joist Cladding on the fire exposed side Cavity insulation Cladding on the unexposed side

(a) Cross-section

(b) typical buckling mode

Fig. 2. Timber frame assembly with I-joists exposed to fire. The rupture of the load bearing I-joist with relatively small flanges is sensitive to sizes and locations of knots. The glue line between the web and flange did not lose its integrity in any of the tests with any of the products that were evaluated. Glue line integrity of finger joints is not relevant for compression members, and this phenomenon is not studied here. Based on the research the design model for I-joists is proposed in Annex I of the revised prEN 1995-1-2:2021.

Acknowledgements The authors would like to thank RISE Research Institute of Sweden, Masonite Beams, James Jones, Metsä Wood and Steico for their material, knowledge and support.

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2. Forum Wood Building Baltic 2021 Behaviours of Timber-concrete Composite Members | Karina Buka-Vaivade et al.

Behaviour of timber-concrete composite members Karina Buka-Vaivade; Dmitrijs Serdjuks; Romans Vasiljevs; Jana Gerasimova; Leonids Pakrastins; Imants Mierins, Institute of Structural Engineering and Reconstruction, Riga Technical University, Latvia

Summary Behaviour of timber-concrete composite panels, with the rigid timber to concrete connection, were evaluated. The rigid connection was developed by using the granite chips as the keys. Behaviour of timber-concrete composite panels were investigated by the analytical, numerical, and experimental method. A possibility to 2.55 times decrease maximal displacements by gluing concrete layer to the cross-laminated timber panel and possibility to increase by 28.1 % load-carrying capacity of the timber-concrete composite panels by using the proposed connection production technology were stated. Key words: timber-concrete composite, rigid connection, adhesive connection, glued connection, cross-laminated timber, bending test.

1. Introduction By combining such two materials as timber and concrete, various classical disadvantages of wooden floors can be improved, such as dynamic reaction, bending stiffness, loadbearing capacity, sound insulation and structural fire safety. At the same time, timberconcrete composite (TCC) in comparison with classical reinforced concrete floors allows significantly reduce the self-weight of floor structures, the dimensions of other vertical structures and foundations and transporting costs. Effectiveness of TCC structures are dependent on the type of timber to concrete connection. Semi-rigid and rigid are two types of connections which are used now. The adhesive connection of the TCC members is more effective in comparison with the semi-rigid connections. But it is difficult to predict the quality of the obtained connection with the classical methods of continuous rigid connection production. So, the aim of study is investigation of influence of the granite chips in timber to concrete connection on the behaviour of TCC structural members subjected to flexure.

2. Methods Influence of the concrete layer on the cross-laminated timber (CLT) panel behaviour were evaluated by the laboratorian, analytical and FEM analyses; and behaviour of TCC with carbon fibre plate produced by classical rigid connection dry method and by proposed rigid connection production method. The experiment was realised with four types of specimens. The first specimen was CLT panel with length, width and thickness equal to 2000 mm, 350 mm and 60 mm. The second specimen was glued together identical to the first specimen CLT panel and precast 30 mm thick concrete C20 layer. The third specimen was like the second, but with 1000 mm x 100 mm carbon fibre plate, glued in the tension zone. The fourth specimen was identical to the third, but rigid connection was produced by the proposed method which included gluing of the granite chips to the CLT surface and then placing of fresh concrete layer. All the specimens were tested in three-point bending until the collapse.

3. Results and discussion Experimentally, numerically, and analytically obtained load-displacement curves for CLT and TCC panels with 1.8 m large span are shown in Fig. 1 (left). At a load level of 15 kN in the CLT slab are formed 28.4 mm large displacements, but in TCC panel only 11.1 mm. So, the concrete layer has a significant effect on the deformability of CLT panel.

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Experimentally obtained behaviour of TCC panel produced by classical rigid-connection dry method is characterized by less stiffness in comparison with the analytically and numerically obtained. Moreover, the behaviour of TCC with carbon fibre plate which was produced by classical rigid connection method is even worse than TCC without carbon fibre plate, at the time, then according to the analytical calculation, stiffness of TCC with carbon fibre plate is 1.48 times larger than stiffness of pure TCC. The reason for this is poor quality of the obtained glued connection by classical dry production method. As it can be seen in Fig. 1 (right), the TCC without granite chips develops much larger displacements than those obtained in the calculations, at the load level of 30 kN the experimentally determined displacements are equal to 22.8 mm, which is more than 52 % larger than those calculated with the 3D damage model. The destructive load of this specimen was 32 kN. At the same time, the proposed rigid connection production method provides full composite action of the specimen and additional local strengthening of the concrete layer by granite chips as concrete aggregates. The specimens with the proposed rigid connection solution showed both higher load-bearing capacity, the destructive load was 41 kN; as well as smaller maximal vertical displacements from the applied load, only 5.77 mm are formed at the load level of 30 kN.

Fig. 1. CLT and TCC behaviour in three-point bending (left). TCC with carbon fibre plate with and without granite chips in rigid connection (right).

4. Conclusions The effects of a concrete layer on CLT panel and a poor-quality glued connection on the TCC behaviour were determined. The possibility to decrease more than 2.55 times the mid-span displacements of the CLT panel by adding concrete layer was obtained. The importance of the problem of poor-quality rigid connection was experimentally proved. The poor-quality glued timber to concrete connection does not allow the full composite action. Increase of the load-carrying capacity by 28.1 % and 3.95 times decrease of the maximal vertical displacements at the load level equal to 30 kN of TCC panel using granite chips to provide high-quality connection between timber and concrete layers in comparison with the specimen without granite chips was stated.

5. Acknowledgements This work has been supported by the Latvian Council of Science funded project “Method of correlation of coaxial accelerations in 6-D space for quality assessment of structural joints (COACCEL)” (Nr. lzp-2020/1-0240) and Riga Technical University's Doctoral Grant programme.

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2. Forum Wood Building Baltic 2021 EN17334 – a first-time user experience | Karlis Pugovics

EN 17334 – a first-time user experience Karlis Pugovics, researcher1, guest lecturer2; Uldis Spulle, senior researcher2; Kristians Klancbergs, student2 1 2

Forest and Wood Products Research and Development Institute, Latvia Latvia University of Life Sciences and Technologies, Latvia

Summary If one has to sum up modern motto for timber construction, citius – altius – fortius seems to be an appropriate phrase. Advents in materials and, perhaps more importantly – fastening systems have made large scale timber construction the modern reality. Gluedin rods have been a hot topic in timber engineering research field for many years now. A great deal of problems regarding consistent results can be attributed to lack of unified testing standards. Advent of EN 17334 provided research community with a unified method for testing. This paper reflects the first-time user’s experience working with this standard; problems experienced and potential solutions. Key words: glued-in rods, EN 17335, adhesive testing, dense epoxy adhesive.

1. Introduction EN 17334 specifies performance requirements and methods for determining characteristic bond strength values for two-component epoxy (EPX) and polyurethane (PUR) adhesives. Performance requirements are tested by the following testing methods: • Tensile shear test (modified EN 302-1 method). • Delamination test (modified EN 302-2 method). • Shrinkage stress test (modified EN 302-4 method). • Multiple compression shear test (modified EN 302-8 method). As stated before, this paper reflects experience and lessons gained during tensile shear testing processes, which were done before more thorough tests regarding performance of glued-in rods.

2. Methods For tensile shear tests a dense (density around 2.00 in with ASTM D792, viscosity 300 000 mPa∙s) two component EPX based adhesive was used. Dense adhesive was chosen with regards to ease future industrial application in factory setting. Three types of samples were made from European Beech (Fagus Sylvatica) in accordance with modified EN 302-1 requirements, using different adhesive line thicknesses: close contact glue line (<0.3 mm) and thick glue lines (1 mm and 2 mm) as seen in Fig. 1. Five different treatment programs were used in testing, named A1 to A5 as per standard requirements. 12 specimens for each sample population were fabricated in order to produce 10 valid test results. Beech elements were conditioned in standard climate of 20 ⁰C ± 2 ⁰C and 65 RH ± 5 RH for 30 days before bonding resulting in average MC of around 12 %, average density of beech elements was calculated to be 745 kg∙m‒3. Beech elements were made from untreated, straight grained material in order to ensure reliable test results.

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Fig. 1. Test samples used in testing. Left, from top to bottom: samples with close contact glue line, 1 mm and 2 mm thick glue lines. Right: samples marked red – 1 mm glue line, blue – 2 mm glue line, green – close contact glue line. Testing was done in symmetrical gripping setup with a constant crosshead speed of 2 mm∙min‒1 in order to ensure the desired time to reach failure which was recorded to be around 80 s for all samples as seen in Fig. 2.

Fig. 2. Test setup for all samples. Here a sample being tested in wet state is shown.

3. Results and discussion Average tensile strength values (in bold) and required values (in brackets) for each sample population are given in Table 1. During testing, it was evident that the desired values cannot be reached and testing for sample populations A4 and A5 was not started. Table 1 Sample Close contact population adhesive line A1 8.7 (10.0) A2 3.9 (6.0) A3 5.4 (8.0) Note: all values are given in N∙mm-2

1 mm thick adhesive line 7.2 (8.0) 3.3 (4.0) 5.1 (6.4)

2 mm thick adhesive line 7.2 (7.0) 2.6 (3.5) 3.8 (5.6)

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2. Forum Wood Building Baltic 2021 EN17334 – a first-time user experience | Karlis Pugovics

Visual inspection of wood failure ratio results was recorded to be from 90 % to 100 % for all adhesive line thicknesses in sample populations A1 and from 0 % to 10 % in populations A2 and A3. Upon closer inspection it was evident that the failure of reaching the required strength values can be attributed to the fact that pressureless gluing technology when using dense, high-viscosity adhesives does provide a thicker adhesive line than desired, as illustrated in Fig. 3.

Fig. 3. Prepared sample with nominal adhesive thickness of 2 mm (mark ‘B’), actual value for this was measured to be between 2.5 mm and 3.1 mm as a result of excess adhesive (mark ‘A’). For close contact adhesives actual adhesive line thickness was measured to be between 0.5 mm and 0.8 mm, for 1 mm adhesive line – 1.7 mm … 2 mm, for 2 mm adhesive line – 2.5 mm … 3.1 mm. To mitigate this issue, a modified glueing technology was developed and is currently being tested.

4. Conclusions While providing research community with much needed unified testing methodology, test methods do have some problems with dense and high-viscosity adhesives. Further testing to mitigate these problems and produce reliable results is currently being done.

5. Acknowledgements In accordance with the contract No. 1.2.1.1/18/A/004 between “Forest Sector Competence Centre” Ltd. and the Central Finance and Contracting Agency, concluded on 17 April 2019, the study is conducted by the Forest and Wood Research and Development Institute with support from the European Regional Development Fund (ERDF) within the framework of the project “Forest Sector Competence Centre”.

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2. Forum Wood Building Baltic 2021 Wood frame solutions for free space design in urban buildings. | Aivars Vilguts

Wood frame solutions for free space design in urban buildings Aivars Vilguts, Dr.-ing; Haris Stamatopoulos, Assoc. Prof.; Kjell Arne Malo, Prof. Norwegian University of Science and Technology, Norway

Summary The major challenge in designing mid- and high-rise timber buildings is the fulfilment of serviceability requirements and comfort criteria, especially overcoming the limitation with respect to wind-induced lateral deformations and accelerations. The purpose of the present extended abstract is to evaluate the feasibility and the limitations of momentresisting timber frames with semi-rigid connections under service load according to the present regulations. The parametric analyses of planar moment-resisting timber frames and experimental tests of semi-rigid beam-to-column connections were performed to evaluate the overall serviceability performance of the frames. The use of moment-resisting timber frames as lateral load-bearing system can be convenient for mid- and high-rise timber buildings. Key words: lateral stabilization, moment-resisting timber frames, timber buildings, moment-resisting connections, moment capacity, rotational stiffness, full-scale tests.

1. Introduction Timber buildings in comparison to concrete or steel buildings are considered lightweight and possess moderate stiffness characteristics. This renders them prone to wind-induced loading, which can result in excessive flexibility, lateral deformations, and vibrations. Therefore, the major challenge in designing mid- and high-rise timber buildings is the fulfilment of serviceability requirements and comfort criteria, especially overcoming the limitation with respect to wind-induced lateral deformations and accelerations. Two main structural designs are used to provide necessary lateral stability to the mid- and high-rise timber buildings: panel and post-and-beam structures. The lateral stability with panels is provided through shear walls; on the other hand, post-and-beam structure provides stability through diagonal bracing or moment-resisting connections. However, buildings with shear walls or diagonal bracing have strong architectural restrictions and can impair comfort criterion [1]. Nevertheless, in post-and-beam timber buildings, certain types of connections are characterized by low stiffness [2]. This is especially true in the case of beam-to-column connections, where connections usually have minor rotational stiffness and result in ineffective moment transfer or excessive deformations. Without some form of bracing or moment resistance through connections or a combination of both, the overall structural stiffness can be severely reduced. The structural performance of moment-resisting timber frames has not been fully investigated. Furthermore, the lack of knowledge of proper design and standardized solutions of moment-resisting timber frames is an obstacle in implementing such a structure. Therefore, the aims of this extended abstract are to explore the feasibility and limitations of moment-resisting timber frames and to develop a beam-to-column connection technique with sufficient moment capacity, rotational stiffness and high damping for use in mid- and high-rise timber buildings

2. Methods The feasibility and limitations of moment-resisting timber frames were evaluated by parametric analyses and carried out by ABAQUS Finite Element software. The parametric analyses investigate the effects of the rotational stiffness of beam-to-column and columnto-foundation connections, storey number and height, number and length of bays, column

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cross-section dimensions and spacing between frames on the overall serviceability performance of the frames. The moment capacity, rotational stiffness, and equivalent viscous damping of beam-tocolumn timber connections with two planes of long screwed-in threaded rods and steel coupling part were experimentally investigated by quasi-permanent cyclic loading and monotonic loading. The general experimental layout is shown in Fig. 1. (a) (b) (c)

(d)

Fig. 1. (a) ‒ Beam-to-column moment-resisting connection; (b) ‒ experimental set-up; (c) ‒ steel coupling part; (d) ‒ threaded rod.

3. Results and discussion The main aim of the parametric investigation was to explore the possibilities and the limitations of moment-resisting timber frames designed in accordance with the present regulations. The parametric investigation results showed that the minimum rotational stiffness of beam-to-column connections should be at least 12500 kN·m/rad to fulfil the lateral displacement and acceleration requirements. Furthermore, slender frames, that is, frames with height / length ratio > 1.5 are hence not recommended. In total five tests were caried out until failure under monotonic loading. No initial slip was observed in any of the tests, the specimens demonstrated immediate load transfer. All connections failed due to withdrawal of threaded rods in the upper side of beam. The average moment capacity for connections was 86 kNm and rotational stiffness 7020 kN·m/rad. Finally, with respect to energy, the mean equivalent damping measured from quasi-permanent cyclic loading tests was 7.0 %.

4. Conclusions The connections based on long threaded rods and steel coupling parts will require 3‒5 planes of rods to achieve 10 000 kN·m/rad to 20 000 kN·m/rad and fulfil requirements of moment-resisting timber frames, with respect to lateral displacements and peak accelerations. Based on the parametric analyses, the use of regular moment-resisting timber frames as a lateral load-bearing system can be convenient for mid- and high-rise timber buildings depending on wind speed and terrain.

5. Acknowledgements This study has been carried out within the Woodsol project, a project funded by The Research Council of Norway and led by Kjell Arne Malo at NTNU (NFR Grant 254699/E50). [1] [2]

H. Stamatopoulos, "Withdrawal properties of threaded rods embedded in gluedlaminated timber elements," Ph.D. Thesis, Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, Norway, 2016. R. H. Fairweather, "Beam column connections for multi-storey timber buildings," University of Canterbury, Master Thesis, 1992.

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2. Forum Wood Building Baltic 2021 Modular retrofitting solution of buildings | Anatolijs Borodinecs

Modular retrofitting solution of buildings: the example of the first pilot building in Latvia Anatolijs Borodinecs, Dr. sc. Ing., Elina Barone, M. sc. ing., Tatjana Odineca, M. sc. Ing., Riga Technical University, Latvia

Summary Residential buildings are one of the crucial energy consumers. Vast majority of the buildings were constructed after World War II. Almost all buildings require urgent retrofitting due to the very poor thermal insulation properties of their external building envelope. There are many building retrofitting technologies available on the market. However, thermal insulation technologies such as rendered and double facades require large amount of on-site human working hours. One of the most promising technologies is a modular retrofitting. In scope of this study the description of modular retrofitting process performed in Latvia is described. The paper describes the process from an architectural project till the final realization. The main challenges faced during the retrofitting process are development of panel layout, integration of electric wires and solution of junctions to minimize share of thermal bridges. Key words: building stock, retrofitting, prefabricated panels, wooden frame.

1. Introduction Prefabricated thermal insulation panels are relatively new and not yet widely used for mass retrofitting of residential buildings. Meanwhile, the experience gathered so far has shown significant benefits of modular retrofitting. The main of them are reduced number of on-site workers and improvement of overall quality. The European Union research projects such as RENEWSchoo, MORE-CONNECT, ANNEX activities, Ri.Fa.Re, etc. have studied modular retrofitting in detail and have proven that the use of prefabricated panels for retrofitting ensures moisture safety, improves overall thermal performance and provides better quality. Currently almost all prefabricated renovation solutions for apartment buildings are based on wooden frame. Application of the modular multi active facades requires precise data on the building geometry and production process. 3D laser scanning technology in combination with BIM allows precise building measurements and development of prefabricated thermal insulation modules. A number of theoretical and practical studies have proven the benefits of 3D laser scanning in further project development in BIM environment.

2. Methods This study is based on the use of 3D laser scanning and software for data processing. The 3D building model provides all involved parties with correct data on building measurements. The data can be easily imported in CNC production and energy simulation. For panel design, SEMA software is widely used across the Europe. It allows data import from .DWG, .DWX, .3DS, .SHP and other formats. Extra extensions allow direct .IFC import. IFC format also can be used in most popular independent dynamic energy simulation software such as IDA-ICE, RIUSKA and IESVE. However, the embedded energy simulation modules in REVIT, ArchiCAD and AutoCAD allow easier energy analysis while minimizing errors due to data transfer and conversion. The general description of data preparation is shown in Fig. 1.

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(a)

(b)

2

(c)

Fig. 1. Application of 3D laser scanning for preparation of retrofitting documentation: (a) scanner positions; (b) surface model of a two-storey apartment building visualized with Leica Cyclone software; (c) steel coupling part; (d) threaded rod.

3. Results and discussion As a demonstration building, a two-storey brick building was selected to test a prefabricated panel for thermal insulation of a building envelope. In total, the panel mounting took five working days and required six workers on the site. Five days included also the time to deal with problems with replacement of some panels. Taking into account the gained experience, the panel mounting time can be reduced up to three working days for similar buildings. Steps and examples of retrofitting process are shown in Fig. 2.

5 days panel mounting process/5 workers on-site Panel production – 25 days Architectural project - 1 month 3D scanning Fig. 2. Steps and duration of retrofitting process and examples of panel mounting. The total construction cost was 57 215 Euro or 275.50 Euro/m2, which is more expensive in comparison to rendering facades technology. Panel costs were 275.50 Euro/per wall square metre.

4. Conclusions The construction costs of retrofitting process are expensive in comparison to traditional retrofitting approach. However, it provides better construction quality and significantly reduces time of on-site work. Use of 3D scanning allows fast and precise architectural design, dynamic energy audit, automated development of prefabricated panel layout and documentation of all data for future control and analysis.

5. Acknowledgements This study was supported by the European Regional Development Fund project “NEARLY ZERO ENERGY SOLUTIONS FOR UNCLASSIFIED BUILDINGS”. This study was supported by the European Commission within the framework of the Horizon 2020 program. This support is gratefully acknowledged. http:// www.moreconnect.eu

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2. Forum Wood Building Baltic 2021 Weather exposed CLT construction – observations and improvement concept | Kristo Kalbe

Weather exposed CLT construction – observations and improvement concept Kristo Kalbe, MSc 1; Villu Kukk, MSc 1; Targo Kalamees 1 2

2,1

Tallinn University of Technology, nZEB Research Group, Estonia Smart City Centre of Excellence (Finest Twins), Estonia

Summary Moisture safety of precipitation-exposed timber construction must be increased. We observed the construction works of a cross-laminated timber (CLT) building and designed connection details which deter wetting of the CLT. The most sensitive area to wetting was the end-grain edge of a CLT panel. Moisture content remained critical in structures where drying was prohibited. We suggest using liquid-applied membrane coating on the endgrain edges. Horizontal CLT panels should be covered with self-adhesive membranes and vertical CLT panels with temporary clear weather protection foils. Key words: cross laminated timber, wetting, moisture safety, dry-out, case-study.

1. Introduction Wetting of timber structures during erection can have a harmful effect on their durability and could lead to adverse health effects due to microbial growth. Researchers suggest using whole building weather protection (e.g., a tent) to avoid this. Another solution could be using local protection measures on precipitation-exposed timber. We analysed the construction works of a CLT building (Fig. 1, left, floor area 1320 m2) which was exposed to precipitation, and protective measures were used scarcely. We determined critical joints regarding wetting and proposed a set of activities that help to avoid such occurrences.

2. Methods We visited the site regularly and captured as much of the occurring issues as objectively and promptly as possible. We looked for signs of wetting – such as stained wood (Fig. 1, middle), shrinkage or swelling, or the presence of free water on the surface of CLT. We then measured the timber moisture content (MC; Fig. 1, right) according to EN 13183-2:2002 with an electrical resistance-based wood moisture meter and 60 mm long Teflon insulated pins on six measurement rounds from September 2019 to January 2020. To consider the possible influence of weather on the MC, we acquired hourly values of outdoor temperature, relative humidity (RH), and precipitation data from the local national weather station. To estimate the criticality of MC, we used the limit values of 17 % for mould growth initiation, 20 % for low and over 26 % for higher risk of decay initiation.

Fig. 1. Observed CLT construction (left); discoloration of timber due to wetting incidents (middle); measuring timber moisture content with a ram-in electrode (right).

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3. Results Precipitation occurred throughout the construction time, and the CLT was exposed to a sizeable amount of water. Figure 2 shows all the measured MC values and calculated average values for each visit. The most critical junction proved to be the exterior wall to foundation connection. There was a rubber band under the exterior wall edge to prevent moisture ingress, but in many cases this solution did not prevent the wetting of the CLT (e.g., Fig. 1, middle). Water got between the rubber band and timber. 55

Moisture content, %

45

Installation of CLT wall and ceiling panels on site

35 25

26 %

Installation of external doors and windows

1st floor concrete pouring

Installation of external wall insulation

1st floor underfloor heating

20 %

15 17 % 5

Average end-grain Average found.-wall

Sealing Installation skylight of roof shafts insulation and membrane

Average int. wall 04. Oct. 13. Sept. Around the perimeter

25. Oct. 11. Nov. End-grain

19. Dec. Int. wall

31. Jan. Time, dd.mmm

Fig. 2. Measured MC of CLT panels during construction. Filled markers show the average values. and the dashed lines represent the trend of average values.

4. Conclusions Our findings correlate with other studies and show that the most sensitive area to wetting is the end-grain on the CLT panel. We suggest using a liquid-applied membrane coating on the end-grain edges of CLT panels, that must be installed in the factory and must cover the whole cut-edge of the CLT panel regardless of cut-outs for fastening or other irregularities. Intermediate ceiling and roof panels must be covered with weather protection membranes to avoid wetting due to possible water puddles on the horizontal surfaces. The membrane used on the intermediate ceiling must be suitable for indoor use, i.e., not emitting harmful substances. The membranes must be installed in the factory, and all the connection joints and feed-throughs must be taped with water resistant tape on site immediately after the installation of the CLT panels. Self-adhesive membranes are suggested. Additionally, we suggest using a clear foil to protect the vertical sides of the CLT panels from direct water contact. The foil must be clear, because it is then easier to detect accidental water flow behind it. The foil should also withstand strong winds. Thin packaging foils are thus not recommended. The foils must be fixed to the plinth immediately after installation with a water-resistant tape to prevent splashing water getting under the foil. The use of temporary protection foils could be omitted if the vertical CLT panels are also covered with permanent weather protection membranes in the factory. These membranes could help to improve the airtightness of CLT structures as well. The described protection measures should be taken as general guidelines and used together with fast installation process. If wetting does still occur, then moisture must be dried out before covering the structures. For more details, please read “Identification and improvement of critical joints in CLT construction without weather protection” by Kalbe, Kukk and Kalamees (2020). DOI:10.1051/e3sconf/202017210002.

5. Acknowledgements This research was supported by the Estonian Centre of Excellence in Zero Energy and Resource Efficient Smart Buildings and Districts, ZEBE (grant No. 2014-2020.4.01.150016) funded by the ERDF and by the Estonian Research Council (grant No. PRG483), and by the European Commission through the H2020 project Finest Twins (grant No. 856602).

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2. Forum Wood Building Baltic 2021 Automated design and analysis of modular timber buildings | Renee Puusepp

Automated design and analysis of modular timber buildings Renee Puusepp, Creatous Solutions, Estonian Academy of Arts, Estonia Key words: architecture, offsite construction, design, mass-customiseable models, production, industrial construction system.

1. Introduction The design has become one of the most critical barriers in offsite construction. While the construction process has generally reduced, the design time has significantly increased, making the design phase unproportionally long. This is often due to the need of making design production ready and preparing machine-readable instructions (i.e. CNC files).

2. Connecting an industrial building system with an embodied carbon calculator One way to solve this problem is to automate the design phase by reusing or repurposing previously developed building components and utilising repeatable yet variable design patterns ‒ mass-customiseable house models. It is clear that no house design can make up such a model alone; a single design can only be an instance of such a model. A masscustomiseable house model includes a limited set of modular components that can form a virtually unlimited number of design instances. If all components used in the design process are prepared for production well before individual design instances are generated, the production lead time can be significantly reduced. Industrial construction systems can provide content and framework for architects to design masscustomiseable models. The 369 Pattern Building system was developed exactly for this purpose. Fig. 1. The 369 Pattern Building industrial It is an industrial construction construction system. system for designing and constructing up to 7 floor high wooden buildings of different typology and appearance. The system can be used for buildings with a clear span of up to 8.5 m. A pattern building can be a house, office, school, kindergarten, hospital. Pattern buildings are flexible and adjustable to plots of various shapes and in different spatial contexts.

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2. Forum Wood Building Baltic 2021 Automated design and analysis of modular timber buildings | Renee Puusepp

The design is suitable for construction in the climatic conditions of Northern and Central Europe. Pattern buildings alternate in function, size and outline, facade solutions as well as utility systems. Pattern buildings are designed to adjust to the varying construction regulations and standards set in different countries and regions. While standard components of the 369 Pattern Building system can be used in the traditional design process, the discrete modular nature of the system makes it particularly suitable for developing configurators for fully automating the design process. Such configurators developed by Creatomus Solutions are based on decision graphs, where the nodes are modular components connected into a schema by the act of selection.

3. Conclusions Using predesigned modular components open up the possibility Fig. 2. A design instance in the the ‘decision tree’ of calculating production costs of of a mass-customiseable house model. designed buildings in real time. Besides rough cost estimation, configurators can also calculate other parameters attached to such components, such as calculating various life-cycle parameters. The presentation at the Wood Forum Baltic 2021 will briefly introduce technologies for automating the design and calculating embodied carbon footprint of 369 Pattern Buildings, developed by the Estonian Academy of Arts, Creatomus Solutions and Nomad Architects.

Fig. 3. Online house configurators by Creatomus Solutions.

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FORUM ORGANIZER INFORMATION FORUM HOLZBAU RIGA TECHNICAL UNIVERSITY TALLINN UNIVERSITY OF TECHNOLOGY

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Photo credit: Andra Marta Photography


FORUM HOLZBAU (Timber Construction Forum) was established 25 years ago by professors very active in timber engineering of universities from Germany, Austria, Switzerland, Finland and Canada. They aim “to support and coordinate science, research and education in the field of sustainable construction and to promote, in particular, timber construction”. FORUM HOLZBAU achieves the goal through its pan-European program of conferences and exhibitions: events that encourage participation from architects and engineers, manufacturers and suppliers, professional institutes, university departments, research centers and other players engaged in pushing forward the boundaries of modern timber construction.

Contact: Hugo Karre

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Zero energy buildings theme consolidates research topics of energy performance, building physics, indoor climate, building services and of some architectural elements like massing and daylight. Key research initiatives are targeted to the development of technical solutions and calculation methods for highly energy performing and zero energy buildings within active cooperation with other research areas such as architecture, construction economics, building materials and energy production which all well represented in ongoing Zero Energy Center of Excellence in Research ZEBE. Another important research field is formed by topics of renovation of buildings and improvement of existing building stock. Modern technological NZEB test house and climate chamber for studies in building physics allows to use several room configurations in order to simulate office, school or residential buildings. Currently, measurement setups have been built to north and south orientated walls especially for moisture performance analyses of highly insulated external walls. Indoor climatic conditions, including humidity, are well controllable. Contacts: Jarek Kurnitski (jarek.kurnitski@taltech.ee), Targo Kalamees (targo.kalamees@taltech.ee), Martin Thalfeldt (martin.thalfeldt @taltech.ee).

nZEB Test House (left). Climate chamber for studies in building physics (right)

The main goal of TRAC 4 SERIAL is to reach higher energy performance using renewable energy and renovation with prefabricated modules. The new renovation model should become affordable for everyone and be way more efficient than conventional or traditional renovation projects. The TRAC 4 SERIAL project will develop a new NetZero-Energy renovation concept that offers high living comfort, high efficiency and quality, minimum refurbishment durations and innovative financing, thereby achieving a sustainable energy standard. In order to achieve this we will bring together relevant stakeholders and deciders from industry, housing sector, residents and research institutes for fostering and scaling-up of deep energy refurbishments of multifamily-buildings by using prefabricated components produced in serial productions. The project will create a win-win offer for all participants and gives advantage also for political deciders and stakeholders from international to regional and local level. An international network with strong partners, as it has already been formed with this seed money project and also already exists in numerous expressions of interest from Lithuania, Sweden, Finland, and Belarus, can make this contribution. Contacts: Targo Kalamees (targo.kalamees@taltech.ee), Knut Höller (hoeller@iwoev.org).

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The DRIVE 0 concept is based on developing circular deep renovation solutions and supporting consumer centered business models for 7 specific study and demonstration cases as real environments. Tallinn University of Technology and Timbeco are DRIVE 0 partners from Estonia. In Estonia a three-storey apartment building will be renovated by using timber frame prefabricated insulation elements based, balanced ventilation with heat recovery, and building integrated technologies. Prototype measurements and modelling showed that the mineral wool wind barrier with high thermal resistance and vapour permeability is the key component of a well-functioning building envelope. Solutions where water vapour resistance of the wind barrier, thermal conductivity and sensitivity to mould growth are higher compared to mineral wool (e.g. gypsum board with paper surface, OSB or plywood), may cause the humidity over-limit accumulation, high mould growth risk and envelope degradation. The potential of drying out of the initial moisture from existing walls plays an important role in the hygrothermal performance of the building envelope. Red more https://www.drive0.eu/ Contacts: Kalle kuusk (kalle.kuusk@taltech.ee), Targo Kalamees (targo.kalamees@taltech.ee), Madis Lobjakas (madis.lobjakas@timbeco.ee).

DRIVE0 case-study building in Estonia (left) and installation of prototype (right).

NERO develops and demonstrates technical solutions, which significantly reduce the costs of new nearly Zero-Energy Wooden Buildings and districts compared to the current situation. On site and nearby renewable energy system solutions are studied in order to provide real addition of renewable energy production and to provide solutions, which are optimal on local grid and energy system level. Estonian demo building showed that throughout the energy performance range the most cost efficient was investment in the improvement of the thermal transmittance of windows. If these were possible to install, PV panels installed to the roof would be the cheapest solution to improve the energy performance. Integrated project delivery procurement (design and construction together) and the use of prefabricated wooden structures reduced the constructing cost by half and helped to keep the budget within limits. Read more https://www.neroproject.net/. Contacts: Endrik Arumägi (endrik.arumagi@taltech.ee), Targo Kalamees (targo.kalamees@taltech.ee), Tero Hasu (tero.hasu@kinno.fi).

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Riga Technical university has become a modern internationally recognized university, which conducts internationally competitive research and cooperates with reputable international research institutions, such as the European Organization for Nuclear Research CERN, European Space Agency, Royal Institute of Technology, Sweden, Fraunhofer Institute, Germany, and other.

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WIGO Group is one of the Baltic’s leading CLT and wooden construction material manufacturers, proudly offering its customers high-quality CLT panels, wooden frame structures and structural timber materials, as well as prefabricated houses.

CLT panel production provides a full cycle of wood processing, involving stateof-the-art computercontrolled factory machinery.
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Location: • Latvia, the Baltic region Production premises: • 12 000 m2 Factory capacity: • CLT panels 20000 m3/year • Prefab and modular houses 50—200 units per year Maximum dimensions of CLT panels: 2,95m x 10,5m x 280mm CNC processing table Austrian - Siegel MKS - 2009

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