IMIESA January/February 2024

www.imesa.org.za

IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY • WASTE

handles the pressures of water treatment BUILDING INFORMATION MODELLING The evolving influence of BIM on civil infrastructure

ROADS & BRIDGES

Rehabilitating the Sarnia Road Bridge

PERMEABLE PAVING SA’s new PICP guidelines

IN THE HOT SEAT Our culture is empowering and supportive. Diverse viewpoints, experiences, and skills sets all serve as vital ingredients within multifaceted teams where lifelong learning is supported and encouraged.” David Leukes Managing Director, BVi Consulting Engineers I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 9 N o . 0 1 • J a n / F e b 2 0 2 4 • R 5 5 . 0 0 ( i n c l . VAT )

Manufacturers,

suppliers and Exporters of : PVC Pipes & Fittings HDPE Pipes & Fittings Steel Pipe & Fittings Valves, Water Meters, & all related products

INSIDE

VOLUME 49 NO. 01 JAN/FEB 2024

24 Regulars www.infrastructurenews.co.za www.imesa.org.za

IMESA

Editor’s comment President’s comment Index to advertisers

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The official magazine of the Institute of Municipal Engineering of Southern Africa

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY • WASTE

handles the pressures of water treatment BUILDING INFORMATION MODELLING The evolving influence of BIM on civil infrastructure

Cover Story VEGA handles the pressures of water treatment

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Hot Seat Innovation and excellence drive business expansion in a digital world

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SA’s new PICP guidelines

IN THE HOT SEAT Our culture is empowering and supportive. Diverse viewpoints, experiences, and skills sets all serve as vital ingredients within multifaceted teams where lifelong learning is supported and encouraged.” David Leukes Managing Director, BVi Consulting Engineers

Building Information Modelling (BIM) How BIM will continue to shape civil infrastructure in the year ahead

To ensure optimum efficiencies, water treatment systems demand careful monitoring and management of processes. In the case of a major metropolitan area in the Midwestern United States, managing their massive system is no simple task, with VEGA providing a range of instrumentation solutions for the city’s water company across their sprawling network. P6

IN THE HOT SEAT Within South Africa’s infrastructure arena, the need for exemplary leadership is vital to ensure that the country remains a vibrant socioeconomic hub. IMIESA talks to David Leukes, managing director of BVi Consulting Engineers, about the firm’s unique ability to adapt, win work and grow consistently since 1967, founded on a solid track record for multidisciplinary project delivery. P8

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WATER & WASTEWATER

Water & Wastewater Greywater reuse stands as a promising method for fostering water conservation in green buildings Automation can help bridge WWW skills gaps Enhancing water management with cloud technologies A sustainable solution for clearing blockages and cleaning conduits

A total pump solution

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I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 9 N o . 0 1 • J a n / F e b 2 0 2 4 • R 5 5 . 0 0 ( i n c l . VAT )

ON THE COVER

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Pump Technology

ROADS & BRIDGES

Rehabilitating the Sarnia Road Bridge

PERMEABLE PAVING

The new SA permeable interlocking concrete pavement guidelines

Pipe Systems SAPPMA elevates plastic pipe manufacturing standards

Environment Resilient innovations for a greener future: Adaptable landscapes to climate change

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Roads & Bridges Municipal Focus: eThekwini Staying ahead of the weather with eThekwini’s Forecast Early Warning System

Rehabilitating the Sarnia Road Bridge Msikaba Bridge reaches new heights 14

Recycling Africa’s Roads

Trenchless Technology WSP’s micro-tunnelling project breaks new ground and sets a record

Recycling and building new roads with Astec

Bitumen & Asphalt 19

Geotechnical Landmark Kendal ADF development nears completion Major gabion retaining wall completed for Silver Star Casino Counter-erosion measures key to restoring storm damaged Umdloti coastline

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ROADS & BRIDGES

Guatemalan contractor adds larger Lintec CDP14001M plant

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Vehicles & Equipment 21

Kobelco excavators impress at Raubex

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Cement & Concrete

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New limestone quarry for AfriSam at Ulco

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Transportation

Permeable Paving Plastic cellular grid pavers prove effective for stormwater control

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Lining Systems Long term barriers for long term solutions

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Pilot scale electric bus drive for Tshwane and eThekwini

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VEHICLES & EQUIPMENT

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EDITOR’S COMMENT EDITOR Alastair Currie Email: alastair@infraprojects.co.za DESIGNER Beren Bauermeister CONTRIBUTORS Chetan Mistry, Karina Arumugam, Motlatsi Monyake, Neil Armitage, Sibusiso Mjwara DISTRIBUTION MANAGER Nomsa Masina DISTRIBUTION COORDINATOR Asha Pursotham SUBSCRIPTIONS Email: distribution@infraprojects.co.za ___________________________________________________ ADVERTISING SALES KEY ACCOUNT MANAGER Joanne Lawrie Tel: +27 (0)82 346 5338 Email: joanne@infraprojects.co.za ___________________________________________________

PUBLISHER IMESA (Pty) Ltd P O Box 2190, Westville, 3630 Tel: +27 (0)31 266 3263 Email: info@infraprojects.co.za ANNUAL SUBSCRIPTION: R805.00 (INCL VAT) ISSN 0257 1978 IMIESA, Inst.MUNIC. ENG. S. AFR. © Copyright 2024. All rights reserved. ___________________________________________________ IMESA CONTACTS HEAD OFFICE: Manager: Ingrid Botton P.O. Box 2190, Westville, 3630 Tel: +27 (0)31 266 3263 Email: admin@imesa.org.za Website: www.imesa.org.za BORDER Secretary: Celeste Vosloo Tel: +27 (0)43 705 2433 Email: celestev@buffalocity.gov.za EASTERN CAPE Secretary: Susan Canestra Tel: +27 (0)41 585 4142 ext. 7 Email: imesaec@imesa.org.za KWAZULU-NATAL Secretary: Narisha Sogan Tel: +27 (0)31 266 3263 Email: imesakzn@imesa.org.za NORTHERN PROVINCES Secretary: Debbie Anderson Tel: +27 (0)83 326 3050 Email: np@imesa.org.za SOUTHERN CAPE KAROO Secretary: Henrietta Oliver Tel: +27 (0)79 390 7536 Email: imesasck@imesa.org.za WESTERN CAPE Secretary: Michelle Ackerman Tel: +27 (0)21 444 7112 Email: imesawc@imesa.org.za FREE STATE & NORTHERN CAPE Secretary: Wilma Van Der Walt Tel: +27 (0)83 457 4362 Email: imesafsnc@imesa.org.za All material herein IMIESA is copyright protected and may not be reproduced without the prior written permission of the publisher. The views of the authors do not necessarily reflect those of the Institute of Municipal Engineering of Southern Africa or the publishers.

Bridging the gaps and stimulating growth in 2024

T

he new year is now well under way and for South Africa it’s a momentous one as preparations unfold for our seventh general election following the country’s democratic transition in 1994. In the past three decades, major strides have been made to build an inclusive society, supported by micro and macroeconomic objectives.

The next round of voting will add positive momentum, with around 27,5 million citizens registered to vote of which approximately 4 913 067 are between the ages of 18 and 29, spurred on by a surge in first time voter registrations. The latter is an encouraging sign and a vital one in terms of influencing how political decisions will shape future job creation initiatives for this rapidly growing segment of the population in major industries like construction and manufacturing.

So far, endeavours like the Presidential Employment Stimulus (PES) and Youth Employment Intervention (PYEI) are said to have created over 1,7 m job oppor tunities over the past three years or so.

However, the pace needs to accelerate and it’s only possible through public and private investment within an enabling legislative framework that will be further defined by the 2024 National and Provincial results.

Population growth In 1996, South Africa’s population was estimated to be 40,6 million. Fast forward to the last census in 2022, and counting, and that now stands at some 64 million (with more than 60% under 35 years old), so the growth is exponential and expected to continue.

That of course has major implications not just for new employment creation (with only 10,2 million people currently employed in the formal nonagricultural sector), but also for the infrastructure backbone required to enable socioeconomic sustainability. Urbanisation is intensifying, with around 50% of the population now living within the country’s 17 largest municipalities.

However, to work in practice, there needs to be a parallel focus on urban and rural development, with a key emphasis on strengthening local government performance to maintain and keep critical services

Road investments On roads front, SANRAL’s latest investments in its national network are prime examples of enabling infrastructure that provide a platform for new entrants to the market, with the SOE closing 77 tenders worth R6,43 billion in December 2023. A further batch of new tenders scheduled for release during 2024 will add a further major injection to the market. In accordance with its Interim Preferential Procurement Policy (PPP), at least 30% of these will be allocated to smaller blackowned construction companies, in the process fostering enterprise and professional skills development.

Other ongoing initiatives include government’s Welisizwe Rural Bridges Programme, designed to connect communities, especially those that need to cross rivers. Currently, some 58 rural modular steel bridges are currently under construction nationally – led by SANDF engineers – with 11 bridges completed in KwaZulu-Natal. Again, a positive gain are the local work and supplier opportunities, alongside roles for graduate engineers and candidate construction project managers.

Spearheaded by SANRAL, the Operation Vala Zonke pothole eradication campaign piloted in Standerton is now also gearing up for nationwide application.

Incorporating nanotechnologies, it’s a vital part of ensuring that municipal roads are up to standard.

When roads work, the economy works, and with allied attention given to freight and passenger rail, it sends the right message to local and international investors. That’s alongside all the other priorities, like ending loadshedding.

For government, pre and post the 2024 Elections, it’s about delivering on their mandate and leaving no one behind.

For young South Africans that’s vital for our collective success.

Alastair

To our avid readers, check out what we are talking about on our website, Facebook page or follow us on Twitter and have your say. www.imesa.org.za

IMESA

IMESA

imesa_za

imesa

www.imesa.org.za

The official magazine of the Institute of Municipal Engineering of Southern Africa

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY • WASTE

handles the pressures of water treatment BUILDING INFORMATION MODELLING The evolving influence of BIM on civil infrastructure

The ABC logo is a valued stamp of measurement and trust. IMIESA is ABC audited and certified.

like water, sanitation, electrification, and roads at optimum levels.

Cover opportunity In each issue, IMIESA offers advertisers the opportunity to get to the front of the line by placing a company, product or service on the front cover of the journal. Buying this position will afford the advertiser the cover story and maximum exposure. For more information on cover bookings, contact Joanne Lawrie on +27 (0)82 346 5338.

ROADS & BRIDGES

Rehabilitating the Sarnia Road Bridge

PERMEABLE PAVING SA’s new PICP guidelines

IN THE HOT SEAT Our culture is empowering and supportive. Diverse viewpoints, experiences, and skills sets all serve as vital ingredients within multifaceted teams where lifelong learning is supported and encouraged.” David Leukes Managing Director, BVi Consulting Engineers I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 9 N o . 0 1 • J a n / F e b 2 0 2 4 • R 5 5 . 0 0 ( i n c l . VAT )

IMIESA Jan/Feb 2024

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PRESIDENT’S COMMENT

Since this is the first IMIESA edition for 2024, I’d like to open by wishing all our members and readers a rewarding year as we forge ahead to build and maintain a sustainable infrastructure landscape that enables positive socio-economic growth, measured against key objectives.

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oremost among these is the ongoing need to ensure that essential services are delivered to world class standards that align with South Africa’s commitment to the globally endorsed UN Sustainable Development Goals (SDGs). For developed and developing countries, it’s a race against time to reverse the effects of climate change – brought to the fore at the 28th Conference of the Parties to the UN Framework Convention on Climate Change (COP28) held in Dubai towards the end of 2023.

Ending reliance on fossil fuels – a major contributor to greenhouse gas emissions – was again reinforced at COP28 as a matter of urgency, with all member countries tasked with preparing national climate action plans.

South Africa’s key contribution in this respect is its Just Energy Transition (JET) Investment Plan, as the country progressively shifts its dependence on coal to renewable interventions like wind, solar and green hydrogen.

Floods and droughts One of the most obvious signs of climate change are the rapidly increasing cycles of extreme floods and droughts, which impacts infrastructure and the ability to maintain essential services. To counter and manage these threats, specialist engineering and scientific skills are required.

Allied to this are the routine asset management disciplines – especially operations and maintenance (O&M) – needed to ensure that crucial areas like water demand management, water security and treatment systems are optimised. In South Africa, we need to work much harder to improve our performance in these areas.

The vital role of WSAs This was highlighted at the Water Ser vices Authorities (WSAs) Summit on the

Sibusiso Mjwara, PrTechEng, MIMESA, MSAICE, MWISA, MIPET

IMESA

OUR FUTURE DEPENDS ON HOW WE MANAGE OUR WATER AND WASTEWATER Blue Drop Report (potable water), No Drop Report (water conservation and demand management – especially non-revenue water) and Green Drop (wastewater) Progress Assessment Report, held in Gauteng between 18th and 19th January 2024.

Convened by the Depar tment of Water & Sanitation, the summit was attended by representatives from the country’s 144 WSA municipalities, alongside entities that include EWSETA, MISA, SALGA, and industry professional bodies like IMESA. Keynote addresses were made by the Minister of Water & Sanitation, Senzo Mchunu, and Thembi Nkadimeng, the Minister of Cooperative Governance and Traditional Affairs (CoGTA).

Breaking down the findings of the reports, the primary purpose of the summit was a call for WSAs to develop action plans to remediate or enhance performance across their water supply and/or wastewater systems. The major emphasis is on adhering to engineering excellence and professionalism by having the right skills in place.

Group focus Based on their most recent Blue Drop and Green Drop Certification assessment results, WSAs were divided into four groups, ranked on their aggregated scores, respectively, as either “critical” (67 municipalities in Group 1); “poor” (38 municipalities in Group 2); “average” (27 municipalities in Group 3); and “good” or “excellent” (12 municipalities in Group 4). As an aside, the full Blue and No Drop assessments, and the interim Green Drop progress assessment repor ts were released on 5th December 2023.

During the summit, breakaway sessions took place for each group, with

feedback then given to delegates on high level action plan proposals within agreed timeframes.

In response, a session was then provided for industry stakeholders to respond. Included was a combined presentation by IMESA, ECSA, SACNASP, SAICE and WISA.

Forward strategy The strategy proposed is for Groups 1, 2, and 3 to seek out the expertise of high performing water and wastewater service providers in assisting them to meet benchmark Drop score standards.

Examples include leading municipal WSAs, best in class Water Boards or private sector specialists via mechanisms that include O&M agreements.

The positive spin-off in terms of engaging with high-performing Water Boards is that they have comprehensive in-house resources across the board in terms of water and wastewater process management. Recent examples include the conclusion of an O&M agreement between eThekwini and uMngeni-uThukela Water Board for an O&M contact to manage the former’s bulk sewer infrastructure.

Funding Going forward, whether it’s an outsourced or an in-house solution, proactive results do need funding and accurate budgets. Currently, CoGTA provides a Municipal Infrastructure Grant (MIG) provision of up to 10% for infrastructure asset management, which includes support in attracting and retaining essential skills like process controllers, scientists, and engineers within their geographic location.

There’s currently a low take up on the application and utilisation of this facility. In future, however, applying for this 10% grant might form a compulsory component of any other MIG application.

IMIESA Jan/Feb 2024

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COVER STORY

COVER STORY

handles the pressures of water treatment

To ensure optimum efficiencies, water treatment systems demand careful monitoring and management of processes. In the case of a major metropolitan area in the Midwestern United States, managing their massive system is no simple task, with VEGA providing a range of instrumentation solutions for the city’s water company across their sprawling network.

P

rocess automation through the use of pressure transmitters can be a major aid to the personnel in charge of ensuring the operation of the many moving parts that make up a water treatment system. In the case of this particular water company, they discovered that choosing VEGA for their process automation needs means more than just obtaining precise and reliable pressure sensors.

Left to their own devices Prior to working with VEGA, the water company already understood the benefits of using pressure sensors throughout their treatment system. In theory, these instruments would allow them to easily automate their processes so that they would have more time to work on more pressing matters. Unfortunately for this company, the reality failed to live up to their dream of a streamlined system of processes.

The first unexpected hurdle the company faced was the challenge of using sensors from many different manufacturers. While using instrumentation from a variety of manufacturers worked on a technical level, in practice it proved to be a headache for water company personnel. Chief amongst these issues was the overall end user experience; the devices were difficult to configure and operate,

6 IMIESA Jan/Feb 2024

and since they were using so many different manufacturers’ devices, the knowledge they gained on learning to operate one sensor typically weren’t transferable to using another.

The other major hurdle was in obtaining support for their devices. According to company personnel, years would pass without seeing anyone from some of the device manufacturers. The water company was then quite literally left to their own devices, and so company personnel had to just do their best to optimally configure and troubleshoot scores of devices. This situation continued for some time, and while the company was interested in standardising their pressure devices to a single manufacturer, their experiences thus far had left them without a clear choice of a reliable partner.

That’s before they met VEGA.

VEGADIF 85 pressure transmitters are designed to handle influent and effluent flow metering

Discovering the VEGA experience The water company’s search for a new instrument supplier eventually led them to the process measurement experts at VEGA. What began as a simple exploration into one of VEGA’s pressure sensors turned into a complete surveying of the company’s processes alongside VEGA personnel.

According to water company representatives, they couldn’t

A VEGADIF 85 pressure transmitter with valve block

COVER STORY

believe that VEGA personnel were willing to spend so much time with them – over the course of multiple days – to tour their facilities and meet the people involved in their instrumentation and automation decisions to better understand their needs.

It wasn’t just VEGA’s time investment that impressed the water company; VEGA was able to provide trial units for the company to try out on multiple applications, allowing them to see firsthand what sets VEGA pressure instrumentation apart from what they had used up to that point.

They were impressed by the precision and reliability of the measurements, but what they liked most of all was the ease of use across each of the sensors they tried out. The sensors were easy to set up and configure, and some even offered features like Bluetooth connectivity that allowed operators to wirelessly monitor, set up, and adjust them through the VEGA Tools app.

After exploring what VEGA’s solutions could do for them, the water company realised

they had found the instrumentation partner they were looking for. They have added VEGA sensors across their entire system, and VEGA personnel were there to help every step of the way, not only helping them set up and commission the devices, but also training company operators on how to use the sensors and best leverage them to reach their process automation goals.

recise and reliable P measurements across the system Today, the company utilises VEGADIF 85 pressure transmitters to handle influent and effluent flow metering in numerous locations throughout their system. Its high precision measured value detection makes this sensor capable of measuring very low differential pressures, meaning the water company obtains data they can rely on.

In turn, VEGABAR 38 pressure sensors measure level on tanks, chemical fill and feed systems and make it easy for system operators to view pressure status thanks to the sensor’s configurable colour LED light ring.

VEGABAR 82 pressure transmitters measure at inlets and outlets on vaults.

This transmitter sports an abrasion-resistant ceramic measuring cell, ensuring reliable operation in the toughest of process

VEGABAR 38 pressure sensors measure level on tanks, chemical fill and feed systems and make it easy for system operators to view pressure status thanks to the sensor’s configurable colour LED light ring

conditions, in turn saving the company on maintenance costs.

Recently, the company added another VEGA instrument to their system: the VEGAWELL 52, which they use for measuring the level of their deep wells and the local river. The VEGAWELL 52’s robust ceramic measuring cell offers maximum overload and vacuum resistance, making it a highly reliable addition to the water company’s process automation arsenal.

orging a path ahead in F process automation Together with VEGA, the water company now knows the true benefits of process automation. VEGA’s proven mix of precise, reliable instruments and commitment to customer support means that the water company’s operators are empowered by process automation instead of struggling with usability or maintenance, freeing them to focus on their other responsibilities. In this way, it can be said that VEGA took the pressure out of pressure measurement.

www.vega.com

IMIESA Jan/Feb 2024

7

HOT SEAT

INNOVATION AND EXCELLENCE DRIVE BUSINESS EXPANSION IN A DIGITAL WORLD

Within South Africa’s infrastructure arena, the need for exemplar y leadership is vital to ensure that the countr y remains a vibrant socioeconomic hub. IMIESA talks to David Leukes, managing director of BVi Consulting Engineers, about the firm’s unique ability to adapt, win work and grow consistently since 1967, founded on a solid track record for multidisciplinar y project deliver y.

In our competitive world, what is your personal recipe for success?

DL Success is about having a positive impact, in addition to achieving personal goals. I place a high priority on moral leadership because I respect social responsibility, honesty, and integrity. Gaining the trust of coworkers, clients, and the community is crucial to longterm success.

For me, constant learning and flexibility are key. It’s critical to maintain curiosity, accept new abilities, and be adaptable in a world that is changing quickly. This strategy aids in my ability to overcome obstacles, take advantage of opportunities, and maintain an advantage in the marketplace. Engineers are inherently problem solvers, so challenges should be seen as a chance to interrogate fit-for-purpose solutions that may at

David Leukes, managing director of BVi Consulting Engineers

times be unconventional. That’s what separates the best from the rest.

Significantly, all successful leaders, and the enterprises they lead, have one major thing in common: they embrace innovation. That creates healthy competition and sets new benchmarks for excellence. It also attracts the best talent.

So, a dedication to innovation is an integral component of my success formula, in both my personal and professional endeavours. You need to keep an open mind and encourage the same mindset within your organisation to create a dynamic culture.

Does artificial intelligence (AI) present a threat or an opportunity?

Engineers are not going to be replaced by AI, but we cannot ignore the benefits of this technology as an interrogative and analytic tool. But it’s not merely about adopting new digital tools like AI; it’s about how we can harness advances in information technology to fundamentally reshape the way we design, build, and maintain infrastructure in unprecedented ways.

Building Information Modelling, the Internet of Things, and AI – among other technological advances – are already enhancing project efficiencies, reducing costs, and improving sustainability.

From a BVi perspective we recognise the benefits. We also understand that digitalisation and automation are not an option – they are an imperative for survival and success. For this reason, BVi continues to invest in cutting-edge software and hardware to stay up to date with the rest of the world. That includes investments in education and training programmes for our staff so they are conversant with the latest digital techniques.

As the incoming CESA President what are some of your major goals?

Consulting Engineers South Africa (CESA) has a rich legacy of addressing critical issues in the built environment. It’s now my responsibility to build upon this foundation, leading with vision and purpose in helping shape todays and tomorrow’s physical and social landscapes.

For this reason, I regard it as a great privilege to be appointed as President for the 2024-2025 term, following in the footsteps of exceptional

HOT SEAT Foremost though, we must collaborate with industry in addressing the brain and talent drain leaving South Africa to more lucrative international destinations.

In response, initiatives need to be undertaken to create an environment that not only retains local talent, but also attracts global professionals, including those from Africa seeking a dynamic and rewarding career in our built environment.

What’s the best way to achieve transformation? leaders that have carried the baton in the past, all serving in a voluntary capacity for industry.

As a proud member of the International Federation of Consulting Engineers (FIDIC), CESA recognises its role and relationship within the global engineering community, plus the responsibility of fostering partnerships and knowledge exchange across the continent with our engineering counterpar ts via FIDIC Africa (previously known as the Group of African Member Associations or GAMA).

Together, we can amplify our impact and contribute to the sustainable development of the entire continent by exchanging local best practice experiences conducive to the successful implementation of projects on a local and international scale.

In a world that increasingly demands growth, tolerance, and stability, we must position ourselves as standard bearers in driving forward our mandate. We must actively promote and contribute to an environment that fosters proactive engagement, understanding and peaceful social coexistence.

For transformation to work in practice, it needs to be inclusive rather than exclusive. For BVi, that process starts internally – through our recruitment, mentorship, management development, bursar y programmes, and the BVi Academy. In terms of the latter, candidate engineers with less than two years work experience are selected from across the BVi organisation to attend a 24-month internship programme to accelerate their path to professional registration.

Currently, BVi is a BBBEE Level 1 contributor, so we’re on the right path. In fact, we’re currently one of the largest black-owned consulting engineering firms in South Africa.

Externally, we run supplier development programmes that assist small black companies to become sustainable.

We also have a corporate social investment programme in place to suppor t dedicated individual and community outreach initiatives.

How do you foster a culture of teamwork and excellence within your company?

Our culture is empowering and suppor tive.

Diverse viewpoints, experiences, and skills sets all serve as vital ingredients within multifaceted teams where lifelong learning is supported and encouraged. Mutual respect and trust are the essential starting points to spark creativity.

Equally, adherence to the highest ethical standards is non-negotiable, as are strict health and safety protocols for all projects we design and execute.

In terms of personnel development, we introduced our Dream Machine programme at the star t of 2023 in conjunction with a specialist consultant to fur ther enhance employee engagement – so essential to BVi’s success.

Creative thinkers, honest communicators, enthusiastic workers, productive team players, and adaptable individuals are typically

more engaged when there’s an open, nonjudgemental atmosphere that welcomes their input. It’s the best way to ensure that high per formers remain engaged, realising our Dream Machine vision. As the saying goes, “the dream works, if the team works.”

And in closing?

The most important success factor is the full support and buy-in of the top management structures in the Group, leading by example.

Employees at all levels within the organisation need to see this and to know that our collective efforts are what builds our business.

Because they do, our engineers are committed to pushing the boundaries of what is possible in suppor t of sustainable infrastructure development and a better South Africa.

WORKING FOR BVI CONSULTING ENGINEERS Scan the QR code link to view our recruitment video, showcasing the dynamic world of BVi Consulting Engineers. Our innovative projects, collaborative spirit, and unique vibrant culture define us.

www.bvi.co.za IMIESA Jan/Feb 2024

9

BUILDING INFORMATION MODELLING (BIM)

BIM adoption across the world (Source: Eischet, O. 2022, Medium)

How BIM will continue to shape civil infrastructure in the year ahead As we enter 2024, the construction industry and its professionals will renew their focus on growth and innovation in support of civil infrastructure development.

IMIESA caught up with Shuaib Yunos, Senior BIM Technical Specialist & Coordination Manager: Civil Infrastructure & Mining at AECOM in South Africa, who shares his insights on why digitisation will increasingly be the key enabler – now and in the future.

Shuaib Yunos, Senior BIM Technical Specialist & Coordination Manager: Civil Infrastructure & Mining at AECOM

10 IMIESA Jan/Feb 2024

Y

unos is a prominent global figure and champion in the Building Information Modelling (BIM)/ Digital Engineering space, affiliated with ECSA, SAICE and IMESA. He has worked on a variety of civil infrastructure and mining projects worldwide, and has shared his expertise through various events, conferences, and publications, including training and educating hundreds of professionals across the world.

This led him to winning the Green Hat Award for South Africa at the BIM Africa Innovation Awards 2021, competing against 289 nominations from various countries across the African continent. The Green Hat Award recognises an Exceptional Individual of African descent who demonstrates outstanding achievements and remarkable service in advocating the adoption

of BIM and digital technologies across Africa.

The following are his responses to a range of key questions:

C

M

Y

CM

MY

CY

How would you describe BIM and its benefits in an informal way to a firsttime user?

Let’s say you need to build a house out of LEGO®. You have a bucket containing these pieces of different shapes, colours, and sizes (equating to project teams, roles, design models, etc.). BIM can be seen as the methodology that will enable you to combine these LEGO pieces together to, say, build the best house possible, optimising and informing the usage and placement of each LEGO block.

The bucket will represent the location where you store and access all your pieces – known as a common data environment (CDE). If there is a hole in this bucket or the pieces (information) do not reside in this bucket, it will negatively impact the end asset (the LEGO house). The embracing of BIM in its true form results in infrastructure that is economical, sustainable, intentional, smart, futuristic, and built to last.

If you could use a term or word to describe the role of BIM in the civil infrastructure industry, what would it be?

Foundational.

CMY

K

BUILDING INFORMATION MODELLING (BIM) is rising, and we intend to continue this momentum and see these efforts flourish in 2024.

What are your thoughts on ChatGPT and other disruptors, and their relevance to the civil infrastructure industry and its professionals?

ChatGPT has indeed revolutionised many

Only a few countries/regions globally (like the UK, Netherlands, Italy and Scandinavia) have made BIM mandatory for public projects.

Why the slow take up elsewhere and where does South Africa fit in on the scale?

This is a loaded question, but I will tr y and summarise my response. The most probable reasons are lack of awareness, understanding, value proposition, capital, resistance to change, and digital maturity.

Digital maturity is one I will expand on.

I refer to digital maturity in the context of capability, scalability, accessibility, resources, legislation, frameworks, and strategy. These key elements are integral

industries and how their professionals Example of operate, holding the same promise visual scripting applied to automate towards the civil industr y. There the placing of light have been multiple applications posts. (Source: of AI tools already on a variety of Shuaib Yunos, AECOM) infrastructure projects, with the most

and must be overcome and defined for the successful incorporation of BIM or any digitally transforming system on a national level.

The erratic nature of these factors has hindered developing countries in their pursuit of implementing/mandating BIM on public projects.

As a member of the BIM Community Africa forum, great effor ts have been made by its like-minded members to promote the adoption of BIM and its use in the industry, hosting multiple CoDE•SA events throughout 2023, including the spearheading of getting ISO 19650 accepted as a South African National Standard (SANS). The BIM Tide

recent I have seen being its application to check engineering design compliance on road projects, which was pretty epic.

With the acceleration in technological advancements (Google Gemini has also joined the mix), BIM, AI, ML, computational design, and visual scripting have opened avenues to the industry and its professionals to really push the envelope in infrastructure delivery, including new employment/role/ business oppor tunities evolving with the technological landscape. These disruptors are powerful enablers, but they still require

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BUILDING INFORMATION MODELLING (BIM)

the person behind the wheel to steer them in the right direction.

future challenges of a similar nature, providing automation and agility.

Speaking about visual scripting, what is it in simple terms and could you give us some examples of its application?

What are your thoughts regarding the BIM maturity of South African organisations?

Visual scripting can be described as a logic driven process to meet an end goal. Think of it as a stepped approach to solving challenges, where each step is dependent on the ones prior to arrive at the desired result. By defining this logic, it has the flexibility to be modified to similar future challenges.

An example which would be easy to understand is the placing of light posts along a roadway. If you have a 1 000 light posts, it is a tedious task to place each one manually; worse if there are any changes in positioning to the roadway, resulting in manual modification and replacing of these light posts, which is a painful exercise.

A script that is created to automatically place light posts along a roadway can be created, and when executed/run, can accomplish this task within a minute or two, with the results visually displayed in the design model, confirming correctness or modification.

By setting a reference for the light posts to follow in terms of positioning, the script can simply be rerun to cater for any changes and modifications to the road model, saving an immense amount of time. This script can then be modified and applied to many other applications where placement needs to be automated, with the light post maybe swapped for another object, say a safety barrier. The creation of scripts can take some time initially due to the complexity of the challenges it solves, but once created, is available for all

Most AEC organisations have incorporated 3D parametric modelling into their processes, but that is where it ends. Very few have gotten into working within a CDE, with even fewer working in an openBIM environment. Whilst BIM technologies have really bolstered productivity in firms, it is only a small component to the BIM ecosystem, and is not BIM itself, a common misconception. I hope to see the BIM maturity and digital footprint of organisations grow in 2024.

You recently presented at the ECSA UNESCO conference where you showcased impressive BIM projects on the African continent. Which one stood out to you?

Yes, it was a great honour to be selected to present at this conference celebrating African excellence. The Parcelle O (Project Owner: EWANE assets, BIM Management by Continuum BIM) was the project that stood out to me, being Morocco’s first 100% BIM project, which is a massive achievement.

Parcelle O is the largest offshore park in North Africa located in Casablanca, with the office complex comprising four buildings covering an area of approximately 49 900 m2.

Where are you personally on the BIM journey and what are your ambitions for the year 2024?

I see myself constantly (or at least trying to) keep up with the innovations in my space

BIM model snapshots of Parcelle O. (Source: African BIM Report 2022, BIM Africa)

12 IMIESA Jan/Feb 2024

(which is quite a tall task), with my focus being on BIM Stage 3 as per ISO 19650. My skills ambitions are definitely geared towards learning and growing my expertise in the fields of all things automation, data and AI, and how I can apply these disruptors to optimise teams, systems and business strategies.

Lastly, what is your advice to South African organisations and industry professionals for the year ahead?

Given the rapidly advancing technological landscape, organisations and industr y professionals need to evolve. I believe the industry and its professionals acknowledge this but are hesitant to embark on this unknown path, which can be daunting. I advise reaching out to service providers who specialise in BIM and digital transformation.

These organisations have dedicated expertise in this space and will create a roadmap for you, as well as guide and suppor t you irrespective if you are just starting or want to push the boundaries on your BIM and digital transformation journey.

It is better to be ready, rather than get ready, and by adopting this proactive approach, the civil infrastructure industr y will be capable of executing projects the day BIM becomes mandatory in South Africa, including landing international work and increasing competitiveness.

Professional bodies need to incorporate digital engineering experts into their executive boards, frameworks, and processes, so that the career paths of the engineer and technologist now and in the future are catered for, resulting in more registered, agile, and innovative professionals in our South African industry.

ENVIRONMENT

Resilient innovations for a greener future

ADAPTABLE LANDSCAPES TO CLIMATE CHANGE Climate change is defined as the substantial variation in average weather conditions over several decades or longer becoming, for instance, warmer, wetter, or drier. Since 1990, the average temperature in South Africa has risen twice as quickly as the average temperature globally (0.7°C).

T

he National Adaptation Plan for South Africa states that there is evidence of an increase in extreme weather events, including a modest extension of dry spell durations, an increase in heat waves (sometimes manifested as part of the El Niño effect), and an increase in rainfall intensity (floods). Furthermore, there has been a significant shift in the rainfall seasonality in South Africa.

Climate change also impacts severely on water scarcity, which is a result of more frequent droughts and water shortages in some areas of the nation. For these reasons, we must modify our habits and way of life to build a sustainable future in a world where climate change is more than just a catchphrase. Frequently regarded as merely an aesthetic improvement, landscaping is essential to this change.

Steps for landscape resilient designs to mitigate climate change barriers

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Hydrozoning: Group your plants with similar watering requirements to reduce the needless use of water. This can be achieved by incorporating the following zones within your landscape design: • High water use zone: covering 10-30% of the garden. This area requires more water (750-1 000 mm per year).

• Medium water use zone: Covering 20-40% of the garden. Plants in this zone receive limited water (500-750 mm per year).

• Low water use zone: Covering 30-60% of the garden. This area should receive (300-500 mm per year) of water.

• Very low water use zone: This zone should cover the largest part of the garden (< 300 mm of water per year).

Indigenous plant selection: As climate change unfolds, it alters ecosystems, thus making it critical to select plants such as Aloe africana and Portulacaria afra (known as the Spekboom/Elephant bush), grown in the

2

low water usage hydrozone, that can adapt to the new environment and thrive. Due to their ability to adapt to the local environment, indigenous plants need less water (which can also be enhanced using mulch), maintenance, and pesticides.

Sustainable materials: Using sustainable materials is just as important to landscaping as using plants. Choose recycled, sustainable, or materials for your landscaping tasks that are sourced locally.

Intelligent irrigation systems: Most reports state that their smart irrigation saves approximately 50% in water use.

Investing in intelligent irrigation systems that can monitor the weather and modify watering schedules is necessary.

Carbon-sequestering landscapes: South Africa is not just the continent’s highest emitter of greenhouse gases, but it also ranks among the top 25 emitters globally. In addition to improving the aesthetics of your landscape, planting trees and shrubs helps absorb carbon dioxide. Trees are a natural resource in our fight against greenhouse gas emissions since they emit oxygen into the atmosphere and absorb carbon dioxide. Constructed wetlands also serve as a huge carbon sequester.

Green roofs and walls: Incorporate green roofs or walls to improve insulation, reduce urban heat island effects, and provide additional green space. These features can also contribute to biodiversity and air quality improvements.

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Rainwater harvesting: Harvest rainwater by collecting it in a water tank. Remember that 1 mm of rainwater is equivalent to 1 litre of water per 1 m2 of surface. You can save up to 30% of water using alternative water sources.

With all these initiatives, not only are you making a lovely outdoor area for you and your family to enjoy, but you’re also improving the health of the entire world when you incorporate sustainability and climate resilience into your garden design. Let your gardening decisions be a statement of your commitment to a more sustainable and environmentally friendly future as we work to mitigate the effects of climate change.

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IMIESA Jan/Feb 2024

13

MUNICIPAL FOCUS | ETHEKWINI

Staying ahead of the weather with eThekwini’s Forecast Early Warning System Recurring floods within the eThekwini municipal boundary are now a regular occurrence, and their severity is increasing due to factors like climate change impacts, rising pollution, population growth and urban expansion. IMIESA talks to Kiyash Sha, senior civil engineer at eThekwini’s Coastal Stormwater Catchment Management Department about their Forecast Early Warning System (FEWS) as a disaster mitigation response.

W

hile it’s not possible to control the weather, the ongoing refinement of eThekwini’s FEWS provides an engineered and scientific approach to potential and real threats and as such is a highly effective proactive tool.

“Initial development began in 2014, with the FEWS system officially launched in 2020.

The early stages focused on the Palmiet River catchment in Durban for the pilot study and from there we’ve expanded to include all catchments within eThekwini,” Sha explains.

To date, it is believed to be the only FEWS implemented as a working model by a municipality in South Africa and mirrors those adopted by the International Network on MultiHazard Early Warning Systems.

“A blend between IT and engineering, the key aspect of an effective FEWS is the realtime collection, analysis, management, and monitoring of meteorological and hydrological data gathered through a series of installed instrumentation that communicate via telemetry networks. Realtime measurements (such as rainfall, wind, water levels, currents, wave behaviour, water temperature, and salinity) all provide vital indicators of the status within catchments, rivers, and oceanic zones,” Sha continues.

This data is used to build automated live models that can be employed to simulate current and future hydraulic and coastal conditions that could exacerbate potential flooding scenarios, as well as providing an early warning system for actual imminent floods. At present there are nine active hydraulic models monitoring in and beyond the eThekwini boundary targeting approximately 200 critical nodes.

Countering infrastructure damage and livelihoods The models essentially identify risks and their related impact for predefined critical areas like road, water, sanitation, and electrification infrastructure. Before any storm hits, the ensuing information is shared with eThekwini’s municipal disaster management teams with the aim of minimising interruptions to service delivery, the prevention of any loss of life, and lowering the extent of any economic impacts through flood response planning.

Inter ventions include the deployment of flood barrier systems ahead of time at strategic points, such as electrical substations. Disaster team resources can also focus on the most problematic areas flagged by FEWS. In parallel, the interpreted data also influences the design and construction of more effective urban drainage and stormwater system inter ventions based

on historical experience; remediation for ageing systems; as well as the ongoing implementation of river and marine infrastructure protection measures, like gabions, to combat erosion. The latter is a key consequence of flooding, exacerbating future scenarios by progressively undermining structures like culver ts, bridges, and buildings. FEWS models can also provide key environmental health indicators like air pollution and water quality.

SAWS forecasts Dovetailing with their own real-time data, FEWS currently uses the South African Weather Service (SAWS) unified forecast model, which generates three potential hazard map forecasts. This includes a fourday model and a higher resolution 24-hour model. The municipality also has access to SAWS radar systems, which allows the FEWS team to see storms in real-time with a 20-minute forecast.

“We also use various global forecast models such as those provided by the National Oceanic Atmospheric Administration and compare these with the SAWS models to determine probability and severity,” says Sha. “Either way, as a predictive tool, the ability to provide sufficient warning has been shown to greatly reduce the socio-economic fallout, and the system will only get better with time, influencing future construction practices where a build-it-better approach is adopted.

For example, we’ve learnt that due to the geology of the eThekwini area landslides are a factor induced by flooding.

“Developments in flood plains and river courses are also a particular concern and need to be countered with appropriate engineered outcomes where practical.

The expansion of informal settlements bordering eThekwini’s rivers also requires urgent attention. The best we can do at present is to inform community leaders of upcoming events so they are aware of what is happening and can then mobilise their people.”

Practical stormwater interventions

Kiyash Sha, senior civil engineer at eThekwini’s Coastal Stormwater Catchment Management Department

eThekwini has a service level charter in place which states that stormwater infrastructure must be designed to accommodate runoff from a 1 in 3-year storm event for urbanised areas; a 1 in 10-year storm event for critical

MUNICIPAL FOCUS | ETHEKWINI

A level gauge installed under a bridge

A level gauge installed in a manhole

FEWS dashboard showing recorded rainfall for a significant event together with the warning alert levels automatically generated. This was for the 13 January 2024 period

points, such as low points; and a 1 in 50-year storm event for bulk infrastructure, such as major culverts and canals.

FEWS model scenarios are based on the assumption that stormwater systems are clear of any obstructions. However, the system is also set up so that the FEWS team can simulate aspects such as blocked culvert portals. For storm events exceeding 1 in 20-years, future low-level crossings and

culverts will be designed so that waterborne debris overtops these structures.

As Sha points out, even a more minor rainfall event can induce flooding where city stormwater systems are not regularly maintained and/or become blocked with litter after a routine clean-up. In the latter respect ongoing community education is important so that residents understand both the environmental and possible flooding hazards.

Real-time collection, analysis, management, and monitoring of meteorological and hydrological data provides an indication of future and imminent threats

“From a FEWS perspective we notify maintenance teams ahead of time so that they can check and clear known problematic areas before a storm comes through,” Sha explains.

Severity mitigation The last few flooding events that affected eThekwini – particularly those in 2022 – exceeded a 1 in 100-year storm. The storm’s severity has also changed the directional flow of some of the water courses, with FEWS models being updated accordingly.

“The reality is that it’s just not feasible to design all infrastructure to accommodate runoff from 1 in 100-year storms. They’d have to be so robust that the cost would be prohibitive. However, the data helps us understand which zones are more affected by flooding so we can budget for a degree of additional infrastructure protection in the worst affected areas or come up with more innovative designs for new structures, like river bridges supported by abutments but with minimal or no piers,” adds Sha. “So far, we’ve already implemented a 15% increase in capacity for new infrastructure to account for climate change. With the adoption of tools like artificial intelligence, we can further refine what we can expect to face in the future in a real-world scenario. The floods will keep coming, so we need to be prepared,” Sha concludes.

IMIESA Jan/Feb 2024

15

TRENCHLESS TECHNOLOGY

proposed micro-tunnelling by specialist subcontractor CSV Construction.

Key advantages

WSP’S MICRO-TUNNELLING PROJECT BREAKS NEW GROUND AND SETS A RECORD WSP’s project, which entails the planning, design and construction monitoring services for the Farm 694 development is set to bring significant benefits to Mitchell’s Plain communities.

T

he project is intended to support the Western Cape Government Department of Infrastructure’s plan to develop several housing oppor tunities for the Kosovo Informal Settlement in the surrounding area. It will also support several other planned developments, as well as the densification of the Mitchell’s Plain area.

The Farm 694 project is the first phase of the ambitious upgrade and will enable de-densification of the larger Kosovo Informal Settlement.

Owing to the project’s proximity to existing services and roads, WSP decided to utilise the contractor’s (Power Smart JV’s) alternative tender offer. The latter

16 IMIESA Jan/Feb 2024

The project is significant for two reasons.

Firstly, it has been minimally disruptive to local communities. While most projects of this class would have required conventional, open, and deep excavation, micro-tunnelling enables limited excavation along the pipeline route.

This is impor tant, explains Du Toit Carstens, Technical Director: WSP in Africa Civils, as conventional excavation (up to 8 m deep) would have posed major safety risks for both construction personnel and the public.

“The project is located within an existing developed area and the full extent of the pipeline is situated within an existing 4 m servitude and existing class 3 arterial road. Conventional construction methods would have substantially impacted the surrounding community. Apart from major traffic disruptions, several open spaces, including parks and schools, would have had to be closed for the duration of the construction period for safety reasons,” Carstens elaborates.

Another reason why the project is notable is because it has the distinction of being the longest length of pipeline and biggest diameter pipeline to be constructed within South Africa using the micro-tunnelling method.

WSP was appointed to this project by the Western Cape Government’s former Department of Human Settlements in September 2018 as a joint venture (JV), whereby WSP was appointed for the

planning, detailed design, and construction monitoring services; while MPAMOT was appointed for construction monitoring and the contract administration services for the bulk sewer and water services upgrade.

Construction commenced in August 2019 and the project was completed in March 2023, with the micro-tunnelling completed in March 2022. Project delays were, however, experienced due to the COVID-19 pandemic.

The full scope of the project includes the installation of a 500 m water main, including all associated pipe fittings and chambers along New Eisleben Road in Mitchell’s Plain, installation of 1 250 m of 1 200 mm diameter sewer pipeline between Merrydale Road and Park Avenue, and the installation of 1 150 m of 1 350 mm diameter sewer pipeline from Park Avenue along Spine Road to the Mitchell’s Plain wastewater treatment works (WWTW).

Furthermore, the project also entailed the construction of all associated structural manhole chambers, including installation of a new collection chamber at the Mitchell’s Plain WWTW. In addition, the installation of a new sand trap structure along the sewer pipeline has been constructed for the removal of grit and debris.

Project challenges A project of this scope invariably has its obstacles, and this one is no exception. “One of the challenges was the continuous changes that needed to be made to the design during the construction phase, in order to accommodate unknown existing services via either temporarily relocating services, the permanent relocation of services or the reconfiguration of existing services,” explains Darren Osborne, Civil Engineer (Civil & Municipal Infrastructure) at WSP in Africa.

Another significant challenge was not knowing the total extent and accurate location of a major existing stormwater pipeline, which clashed with the new bulk sewer pipeline.

“We managed to address these challenges by constructing temporar y stormwater infrastructure, including a siphon structure and sand trap during micro-tunnelling and, thereafter, micro-tunnelling a new stormwater pipeline section over the new bulk sewer pipeline after installation,” adds Arnaud Malan, Civil Engineer specialising in Water & Wastewater, WSP in Africa.

Despite the various challenges faced, the professional team and appointed contractor remained committed to ensuring the successful completion of the project. Working in the team’s favour was the fact that, if required, the micro-tunnelling machine could be run 24-hours a day, merely requiring a switching of operators. While this was done only a few times, the capacity to do so was a strategic advantage in ensuring timeous service delivery.

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YEARS

LINING SYSTEMS

Long term barriers for long term solutions AKS Lining Systems is a manufacturer of thermoplastic liners, specialising in geomembrane and corrosion protective liners.

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he company has grown to become a competitive global producer and its products are exported to more than 30 countries worldwide, where they are used in diverse applications such as mining, environmental conservation, water treatment and general infrastructure.

With its plant situated in Cape Town, AKS Lining Systems naturally also offers strong support to the local South African and SADC regions.

The geomembrane range of products, GEOLINER™, are manufactured from HDPE or LLDPE resins which are considered chemically inert. Designed specifically for use in chemically aggressive environments GEOLINER™ is manufactured using the “flat-die” process and is supplied in 7 m wide rolls in long lengths up to 220 m on a roll. Various surface finishes are available, such as smooth, textured or mega textured. These finishes can be supplied in combinations of either single- or double-sided.

Our state-of-the-art laboratory ensures that all liners produced meet or exceed international standards such as GRI-GM13, GRI-GM17 and the local standard SANS1526.

GEOLINER™ is used in the construction of environmentally critical facilities like landfill sites, tailings and ash storage facilities, ensuring that contaminated effluent does not seep into the groundwater. Crucial conservation of water makes GEOLINER™ the high-performance barrier of choice.

In addition to the GEOLINER™ range, we have our flagship product, AKS™ Corrosion Protection Liner. AKS™ (Anchor Knob Sheet) is a liner extruded with a matrix of anchors. It is used extensively in acid proofing concrete structures by being cast into the concrete.

The mechanical bond into the concrete means the product can be used in a vast range of applications, from mining, sewerage treatment and large outfall sewers. Due to the extremely high wear resistance and abrasion resistance, the AKS™ internal lining in sewer systems is ideally suited for trenchless installation of large diameter pipes.

Global footprint Our international network of distributors and installers are able to offer a complete custom solution to their client base. By utilising this global network, we currently export globally, from Australia, New Zealand, Indonesia, Malaysia and Singapore in the East, including Europe, Middle East and Africa, right across to Chile, Peru and Mexico in the West.

Being ISO 9001:2015 certified ensures that our management system and quality procedures are maintained and reviewed at the highest possible levels. These systems and procedures follow through right from resin suppliers, shipping and logistics, to finished product, testing and delivery.

GEOLINER™ is used in the construction of environmentally critical facilities like landfill sites, tailings and ash storage facilities, ensuring that contaminated effluent does not pollute groundwater

The latest technology and sustainability In order to ensure the highest level of quality is maintained and being able to supply products exceeding international standards, we use advanced European manufactured extrusion lines. These large extruders are designed to utilise the latest technology and operate continuously and faultlessly, with extrusion accuracies close to 3% in terms of thickness, where the current market trend is within a 10% range.

Loadshedding is mitigated by the installation of a Power Generation plant producing 3,5 MW of power.

Quality and traceability For identification, tracking and traceability, all AKS™ and GEOLINER™ rolls are individually labelled and numbered. The in-house Manufacturing Quality Control (MQC) system ensures traceability of each roll and its components right through from incoming resin, in-line production testing, QC testing and final MQC Certification.

With a wealth of experience and knowledge our sales engineers will provide you with technical assistance and custom solutions for your project. Our competent logistical team ensures expert handling and loading of trucks and containers, along with paperwork and all other commercial requirements.

We have an open-door policy, inviting customers to inspect and review their product during manufacturing and testing, giving them peace of mind when materials start arriving on their sites.

Due to the extremely high corrosion resistance, the AKS™ internal lining in sewer systems is ideally suited for trenchless installation of large diameter pipes

IMIESA Jan/Feb 2024

19

2024

IMESA

CONFERENCE

87

TH IMESA

CONFERENCE

ENGINEERING REVOLUTIONISED

CAPE TOWN 6-8 NOVEMBER

SAVE

date

the

Engineering Revolutionised

06 - 08 November 2024 CAPE TOWN | GRANDWEST

CONTACT US FOR DETAILS CONFERENCE ENDORSED BY

t: +27 (031)266 3263 e: conference@imesa.org.za marketing@imesa.org.za www.imesa.org.za

IMESA ORGANISER

THE INSTITUTE OF MUNICIPAL ENGINEERING OF SOUTHERN AFRICA (IMESA)

GEOTECHNICAL

LANDMARK KENDAL ADF DEVELOPMENT NEARS COMPLETION

The Kendal ADF has a project footprint that extends some 2,5 km by 3 km

Led by joint venture partners Concor and Lubocon Civils, the Kendal Ash Disposal Facility (ADF) expansion project – responsible for the storage of ash produced by Kendal Power Station until 2023 – has successfully reached over 80% completion, with an anticipated finalisation date set for March 2024.

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panning an extensive footprint of 2,5 km by 3 km, the project’s components comprise the new 65 ha ADF, two dams each for both clean and polluted water storage, silt traps, an expansive 16 km V-drain system, a significant stream diversion, and some 14 km of access road construction. The principal focus now revolves around the ADF and the basins.

The in-situ materials are clay soils, which calls for a specific construction methodology. Here, selected stockpiled excavated materials are being used in a double-layered low permeability clay for base protection, topped with carefully selected river sand to prevent liner damage.

Cutting-edge drainage and leachate collection The expansion of the Kendal ADF is more than 80% complete

systems are further incorporated to manage water flow efficiently.

Formwork system and leak integrity Concor’s innovative approach in basin construction employs a patented PVC concrete formwork system, boosting efficiency by accelerating the casting panel process. This technique is not only time saving, but also labour efficient. In turn, rigorous quality control measures are in place, a key one being electronic leak detection to ensure construction integrity.

The project is now gearing up to finalise the liner system installation with subcontractor, Aquatan, managing the basins and the ADF concurrently.

GEOTECHNICAL

Major gabion retaining wall completed for Silver Star Casino Gabion Baskets, a specialist manufacturer, supplier and project management installer of environmentally engineered systems, has completed one of its most complex projects to date. This entails the installation of an up to 9 m high and 40 m long mass gravity gabion retaining wall at Silver Star Casino in Krugersdorp. By Alastair Currie

BEFORE Following the failure of an existing CRB section, the client decided to opt for a gabion solution

Phase 1 cross section showing the design methodology for the construction of a 9 m high mass gravity gabion retaining wall

22 IMIESA Jan/Feb 2024

T

his represents Phase 1 of the project, finalised in December 2023, with Gabion Baskets subsequently mobilising on site from January 2024 to complete the second phase. The latter entails the establishment of a new 30 m long wall ranging up to 6 m in height for scheduled completion by the end of February 2024.

In Phase 1, Silver Star Casino’s step back gabion installation replaced an existing wall that was predominately constructed using a concrete retaining block (CRB) system. Over time, this failed in certain sections, resulting in embankment collapse.

Interestingly, however, this CRB wall design did incorporate sections flanked by gabion structures, which were still intact. These were integrated into the overall design for the reestablished wall during Phase 1, entailing some 600 m3 of new gabion installation.

“The fact that the existing gabion flanking structures had stood up so well was a major motivating factor for the client to switch to a complete gabion installation,” explains Louis Cheyne, managing director at Gabion Baskets, who has an extensive background in soil mechanics and gabion construction.

The project was completed over an approximately two and a half month period, with up to 15 workers on site, aided by a backhoe loader.

Labour intensive elements “One of the major advantages for mass gravity gabion retaining walls is that they can largely be constructed using labour intensive methodologies, with var ying degrees of mechanisation, like compaction – since gabions are essentially rock-filled baskets made of Class A Galvanised double-twisted hexagonal mesh,” Cheyne continues.

“This creates much needed work for SMMEs, as well as individual job seekers, where we provide training and construction supervision for the industr y in areas like placement, filling, and lacing to join each integrated basket. However, the secret to a sound design and construct approach still requires expert engineering skills to ensure a safe and sustainable structure.”

Geotechnical investigation As is standard for works of this scale and complexity, a consulting engineer was appointed to carry out a detailed geotechnical investigation, as well as to verify Gabion Basket’s design proposal. For any mass gravity wall above 1,5 m, a registered engineer is also required to sign-off the completed works in terms of its structural integrity.

In this case, the intricacies of the works required experienced gabion installation personnel, with a specialist sub-contractor employed. At peak, the average daily work

GEOTECHNICAL rate was around 20 to 30 gabion baskets installed. To optimise sustainable practices, a percentage of the CRB units – some already damaged during the wall collapse – were broken up for reuse. Some of this resized concrete material was mixed and compacted into the backfill, as well as for supplementary fill in the gabion baskets.

Backfilling and compaction The wall itself rests on an in-situ foundation around 1 m deep, levelled and compacted to around 93% Mod AASHTO density. In turn, the depth of the wall represents 10% of the height, which is standard for these designs.

Extensive excavations were required, during which time a ground tension crack was discovered (a potential contributing factor to the original CRB failure) – right above the area where the new gabion retaining wall was originally planned for construction – emphasising the impor tance of a full geotechnical investigation.

In the end, the new gabion wall stands on solid footings that will provide an engineered and aesthetically appealing structure for generations.

Work in progress on the new mass gravity retaining wall following the removal of the existing CRB section. In the foreground is the existing gabion system, which was incorporated into the overall design. The colour difference is due to natural weathering of the rock fill

include embankments, river protection and mine tip walls, the latter often well above 9 m,” adds Cheyne.

“In 2024, we’re aiming to expand our solutions for mass gravity walls, driven by

strong demand in South Africa and Africa.

These will be backed by our new product offerings that include an expanded geotextile series, which forms a key par t of their integrity,” Cheyne concludes.

Meeting the demand “Phase 1 sets a major project milestone for Gabion Baskets when it comes to design recommendation and construction management oversight. It underscores the success of gabion mass gravity walls – in exper t hands – which due to their approximately 35% permeability are purposedesigned to promote controlled drainage in soil retention roles. Diverse applications

A cross section of a 6 m high wall forming part of Phase 2 at the Silver Star Casino

AFTER Standing 9 m high, the completed retaining wall provides a highly effective environmentally engineered solution, with strong aesthetic appeal.

The wall measures approximately 40 m in length

IMIESA Jan/Feb 2024

23

GEOTECHNICAL

Counter-erosion measures key to restoring storm damaged Umdloti coastline

BEFORE An aerial perspective of the severe washaway at 35 Bellamont Road on the Umdloti beachfront taken in April 2022 and the full rehabilitated section seen in December 2022

AFTER

The April 2022 floods had a catastrophic impact on eThekwini municipality. Between 304 to 311 mm of rain fell over parts of KwaZulu-Natal within a 24-hour period, falling onto already saturated soils due to two preceding days of heavy downpours. For eThekwini’s Coastal, Stormwater and Catchment Management Services Department there were numerous critical areas that required urgent restoration. By Karina Arumugam*

O

ne of the areas that gained a lot of media attention, due to the magnitude of the devastation, was the Umdloti area where the city recorded 250.8 mm in 24 hours at the Umdloti wastewater treatment works rain gauge. This was just below the 1 in 50 year design rainfall depth of 281.5 mm for this area. Rainfall figures were also obtained from an Umdloti resident’s automatic rain gauge, which recorded 277.4 mm for the same event.

The outcome of the rains was amplified due to the preceding days rains, the increase of harden surfaces and removal of vegetation within the catchment area. The large volume of water concentrated at the low points where shifting dune sand – being more susceptible to erosion – resulted in major washaways.

The bulk of the devastation occurred at two major washaways located along Bellamont Road in Umdloti, where 26 apartment units and seven homes were destroyed, with many others compromised in some form. Road access and municipal infrastructure were completely decimated.

In the larger of the two washaways at 35 Bellamont Road, it was assessed that a total of 76 300m3 of material was washed away. The scour depth reached greater than 50 m, which was worsened in the following May 2022 rainfall event. Just over a month later, contractors were on site.

Futureproof stormwater system A critical aspect of the project was implementing a stormwater system that would withstand future flood events. Prior to the floods there was a 900 mm diameter stormwater pipe to the sea.

24 IMIESA Jan/Feb 2024

The low point of the road at 35 Bellamont Road used to flow down the car park into a stormwater inlet connecting the municipal stormwater system at Marine Drive. The catchment area draining to the low point on 35 Bellamont Road was 14.38 ha. During the April 2022 floods a peak rainfall intensity of 119.2 mm/hr, and a subsequent maximum flow rate of 1.3m3/s, was experienced.

A PCSWMM model was generated to design a robust stormwater system that included two 700 mm diameter HDPE solid wall pipes, one connecting across Bellamont Road and the other connecting Marine Drive.

In addition, a 900 mm diameter HDPE solid wall pipe connects to an inlet at the low point on Bellamont Road. An attenuation pond was also constructed between the forest and Bellamont Road to store excess stormwater and reduce surface run-off.

HDPE solid wall pipes were selected owning to their material durability and reliability.

Clean-up operations in progress: at 35 Bellamont Road 26 apartment units and seven homes were destroyed, with many others compromised in some form

GEOTECHNICAL A section of HDPE solid wall pipe installed as part of the overall stormwater management system design

HDPE was also preferred over concrete due to the steep grade, where HDPE pipes are more resistant to surge shock. As construction was restricted due to the steep scoured section, the HDPE pipe sections were butt welded into one continuous length and dragged into place with an excavator.

Backfilling the washaways, optimising slope stability While the stormwater system was more than adequately designed and reinstated, a key overriding priority was to ensure that the slope at 35 Bellamont Road was reinstated to its original integrity. To effect this, the washaway was backfilled to reproduce the original gradient. The average grade of the embankment was 22 degrees, while the unreinforced slope had a safety factor of 1.15.

The fill material used was G9 (Berea red) – 15% of the fill material being fined and the rest coarse. The fill material was end-tipped at the top of the washaway and an excavator and backhoe loader worked to distribute it.

Since the buildings surrounding the site were compromised and unstable, careful attention needed to focus on minimising vibrations during soil compaction. A compaction density of 1 900 kg/m3 was achieved.

To increase overall slope stability, soil nails were specified as the most favourable option on reinstated embankments

Soil nails To increase the overall slope stability, a geotechnical assessment was conducted

by GeoElement and it was recommended that soil nails were the most favourable option to increase the global stability of the embankment. Here, soil nails were installed where the slope was greater than 30 degrees.

Due to the steepness of the slope, the drill rig had to be placed on an excavator bucket during the installation of the soil nails. Pull out tests were conducted to assess the shear resistance between the grout and in-situ material. The friction found was sufficient to achieve a factor of safety of 1.3 at the steepest excavated section. As an added design element, flexible mesh facing was also used to distribute the resistance of the soil nails, which also allowed for the establishment of vegetation.

To further prevent future erosion, field inlets were constructed at the top of the embankment to reduce overland flow; and berms were constructed at 3 m intervals and 500 mm high to reduce the velocity of surface run-off and increase infiltration.

The site was hydro-seeded using fast germinating seeds to provide initial erosion protection. Grass, forbs and trees were

interplanted to reintroduce biodiversity and ecological functionality. Vetiver was also planted along the berms, where the plant’s deep root formations aid in preventing erosion and trap sediment.

Through the efforts of numerous individuals and entities, by December 2022 the area that was obliterated just seven months prior was restored to a much safer and stable site. *Candidate Civil Engineer, eThekwini Municipality: Coastal, Stormwater and Catchment Management Services Flexible mesh facing was used to distribute the resistance of the soil nails, provide additional erosion protection, and promote the growth of vegetation

Vegetation established on one of the rehabilitated embankments along the Umdloti coastline

IMIESA Jan/Feb 2024

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PERMEABLE PAVING An 8,5 km dune roadway built with the Sudpave system forms part of the Kisawa Eco Resort in Mozambique. This is the largest Sudpave design installed to date within southern Africa

Road networks constructed using the Sudpave system at Quoin Rock wine estate, Western Cape

PLASTIC CELLULAR GRID PAVERS PROVE EFFECTIVE FOR STORMWATER CONTROL Permeable interlocking pavers were initially introduced as a concrete product commonly referred to as the “concrete grass block”. Used to this day for applications like lining stormwater channels, low-volume roads, car parks and driveways, their design incorporates open void spacings within an interlocking paving block layout that facilitate drainage, in the process reducing water velocity run-offs that contribute towards erosion and flooding.

T

heir development has fur ther advanced with the introduction of a more sophisticated design that falls within the definition of a sustainable urban drainage system (SUDS). Instead of large voids, these pavers feature an interlocking layout with small pore openings at the joints.

These joint gaps are filled with fine gravel to effect gradual drainage into the established foundation. However, these concrete SUD pavers do require routine maintenance to ensure that the pores don’t become blocked, rendering the system impermeable.

In parallel with concrete grass block pavers is the development of plastic grid pavers, which were first introduced into the European

26 IMIESA Jan/Feb 2024

market some 30 years ago, with increasing adoption in countries like South Africa as a practical and price competitive alternative. A case in point is the Sudpave system, which is manufactured in South Africa under license, with a record of successful installations over the past 17 years.

“The cur rent rate of urbanisation continues to increase the percentage of hard sur faces, which steadily reduces the natural habitat within towns and cities,” explains Gar y Bergesen, head of Sudpave, based in Gqeberha, Eastern Cape and operating nationally.

“Systems like Sudpave respond to this requirement with a degree of controlled stormwater capture and incremental groundwater infiltration – so vital for sustainable ecosystems. The system also functions as a natural bio-filter for hydrocarbon pollutants typically found in parking areas.”

FIGURE 1: The distinctive honeycomb type texture of the Sudpave system

PERMEABLE PAVING

Green parking bays at the University of Pretoria’s Medical Faculty

Distinctive cell structure Like concrete grass block pavers, Sudpave units have an open cell structure. The key dif ference is the honeycomb type configuration (See Figure 1). And like concrete grass pavers, these can either be gravel filled, or planted with grass. However, a key distinction of the Sudpave system is its light weight, plus each unit is fabricated from locally sourced recycled materials.

The grassed Sudpave grid option significantly alleviates the heat island effect, while the gravel option is generally used for heavier vehicle parking areas or roadways due to their higher load bearing capacity, as tested by the CSIR (with report available on request). Either way, there’s a high degree of design flexibility, with each paver measuring 500 x 500 mm and weighing around 1 kg. Four pavers are installed per m2 with layouts accommodating inclines up to 1:8 and localised gradient changes.

Easy to install Ground spikes form part of the bottom of each paver. During installation, these are pressed firmly into the bedding, with each paver locked in place with integrated snap-fit clips.

For optimum results, Sudpave systems should be laid out on a well-drained level sur face that has a layer of gravel bedding.

The thickness of the gravel will be determined by the existing ground conditions and anticipated seasonal rainfall patterns.

Depending on the design, a water recycling system can also been incorporated within the prepared layer works.

“In clay soil, the bedding layer would be thicker, and a sub-soil drainage pipe incorporated to disperse the water to a retention area. However, in sandy free draining conditions, the Sudpave system can be installed with a thinner gravel base.

In all cases, the bedding material should be placed on a geotextile membrane,” Bergesen explains.

The thickness of the bedding material and sub-base will also determine their weight carr ying ability. This can be fur ther strengthened with the use of geogrid mesh beneath the sub-base layer.

Exceptional long-term drainage Thanks to their unique design, some 95% of the surface area is permeable – allowing most of the rain to soak into the ground.

“Once installed, a Sudpave system will function well for generations, with little or no maintenance beyond grass cutting, where applicable. However, to ensure this durability, the Sudpave system should aways be installed by an experienced paving contractor. As with all permeable paving systems, the optimum per formance of the sur face finish is always based on the correct sub-base preparation,” Bergesen concludes.

A PERMEABLE PAVING SOLUTION The highest load bearing plastic grid paver on the market Suitable for pedestrian pathways as well as a heavy truck

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PERMEABLE PAVING

THE NEW SA PERMEABLE INTERLOCKING CONCRETE PAVEMENT GUIDELINES When designed and installed correctly, permeable interlocking concrete pavements (PICP) are highly effective measures forming part of sustainable urban drainage systems (SuDS). However, research conducted by the Universities of Cape Town (UCT) and Witwatersrand (Wits) at sites across South Africa indicate that many local installations have failed. To discover the cause, and put together SA guidelines for the design, construction and maintenance of PICP, the Water Research Commission (WRC) funded a two-year study (2021 to 2023) led by UCT and Wits, culminating in a report on clogging in PICP and the guidelines themselves. By Professor Neil Armitage and Motlatsi Monyake, University of Cape Town

T

he traditional approach to urban drainage in South Africa (SA) is to convey stormwater runoff in pipe and canal networks to the nearest receiving water bodies as quickly as possible.

This, however, leads to increased runoff velocities and volumes, resulting in the erosion and consequent siltation of watercourses, while stormwater pollutants – such as heavy metals, hydrocarbons, faecal matter from inadequate or failing sanitation, and nutrients such as nitrogen and phosphorus – cause a deterioration in the water quality. There has also been reduced groundwater recharge, leading to the dropping of the water table in some areas.

In response, permeable pavement systems (PPS) offer a potential solution. PPS can be adapted to make effective stormwater harvesting and storage devices for fit-for-purpose water reuse. Alternatively, the stormwater could be used to enhance groundwater supplies. Even if the stormwater ultimately drains from the site, the flow rates will have been massively reduced and the water quality improved. Overall, this will increase the resilience of the systems to the impacts of development.

PICP systems are the most widely used PPS – both local and internationally – with the first example in SA being constructed in 2008.

They consist of specially designed concrete

block pavers placed on single-sized stone base layers. Specially designed grooves create gaps between the pavers, termed joints, that allow surface water to pass through.

Specially selected coarse sand in the 2-5 mm range, termed gritstone, is placed between the paving blocks to hold back sediment. Geotextiles may be placed between the bedding layer and the top-most base layer, and between the bottom and sides of the lowest base layer and the in-situ material (Figure 1). The purpose is to separate the layers, improve the runoff water quality, and prevent migration of underlying soil material into the pavement structure. Stormwater is temporarily stored in the base layers, where it may undergo some improvement in water quality due to sedimentation and bacteriological activity. Ultimately, the stormwater infiltrates into the subgrade and/or is removed by subsurface drains.

Key findings from local case studies

FIGURE 1: Typical PICP section

28 IMIESA Jan/Feb 2024

Unfortunately, despite increasing experience in PICP construction in SA and a growing international body of expertise, including the development of both British (BS 7533-13:2009) and American (ASCE/T&DI/ICPI 68-18) standards, infiltration tests carried out between 2017 and 2022 at numerous sites in Cape Town, Ekurhuleni, Johannesburg, and Pietermaritzburg showed that nearly all of them were either clogged or nearly clogged.

Factors that appeared to be contributing to PICP failure included:

PERMEABLE PAVING

• Loose fine soils from surrounding areas transported by wind or runoff onto the PICP surfaces.

• High run-on of sediment-laden stormwater onto the PICP from adjacent impermeable surfaces.

• Poor construction practices leading to premature failure, such as the use of inappropriate filling material such as sand, dirty aggregates, or the lack of suitable edge restraints.

• Little or no maintenance that might have slowed the inevitable clogging of the PICP. In many instances, there was little evidence of the gritstone between the pavers, thus allowing the accumulation of fine sediment material in the lower parts of the openings between the pavers.

• Rutting or differential settlement of the PICP structure owing to the settling of the underlying base layers.

• Unsuitable environmental conditions, such as proximity to vegetation with high leaf or pollen drops or unacceptable sediment exposure.

The SA construction industry currently adapts various international guidelines and standards for the design, construction, and maintenance of PICP. This has resulted in inconsistent PICP practices across the country, as different designers have taken different approaches.

The objectives of the WRC 2021-2023 study were therefore to: 1. Identify the most appropriate PICP designs for SA conditions.

2. Identify effective maintenance equipment and methods.

3. Develop “user-friendly” guidelines for the design, construction and maintenance of PICP in SA.

Method The study had four main components: 1.

L iterature review of the design, construction, and maintenance of PICP through the consideration of journals, case studies, conference papers, books, websites, student dissertations, seminars, standards and guidelines.

2.

Collection of data from existing PICP installations in Cape Town and Gauteng.

3.

Laboratory investigations into the role of geotextiles and pavers in possible PICP clogging.

4. Input from a specially created PICP Working Group comprising experts from academia (inclusive of the USA and UK), local authorities, consultants, and suppliers.

some minor modifications, which was thus termed the Modified ASTM (Mod-ASTM) test (Figure 2).

The PICP maintenance trials

FIGURE 2: Mod-ASTM test apparatus

PICP site selection criteria It was thought that the best way to understand how PICP is performing in SA would be to inspect and test a range of installations in the field. A list of PICP sites was compiled with the assistance of local authority representatives, paving suppliers, and consultants. Most of the sites were situated in and around Cape Town and Johannesburg.

Representative sites were then selected for possible investigation considering their geographical location, pavement design, environmental factors such as vegetation and sediment proximity, site slopes, run-on factors, traffic loading, method of construction, known state of clogging, age, and known maintenance. Permission to perform infiltration and pavement investigative tests on these sites was then requested. Overall, 11 test sites were examined: nine in Cape Town, a coastal, winter rainfall situation, and two in Gauteng, an inland, summer rainfall situation.

he Modified ASTM single-ring T infiltrometer (Mod-ASTM) test There is currently no universally accepted PICP infiltration test method. The most adopted appears to be the ASTM C1701/1701M: Standard Test Method for Infiltration of In Place Pervious Concrete, sometimes called the Single-Ring Infiltrometer Test (SRIT) because it only uses one ring, as opposed to the Double-Ring Infiltrometer Test (ASTM D3385:2009). The latter is preferred for the measurement of soil infiltration rates.

Most PICP testing in this project was carried out using ASTM C1701/1701M / SRIT with

At the time the research was carried out, the only maintenance of PICP being carried out in SA was at a limited number of sites in Cape Town where the joints were regularly blown out to remove clogging material. Compressed air was directed along the joints and the dislodged material swept by a hand broom to the edge of the pavement from where it was collected. Gritstone that was removed with the gross pollutants from the joints was sieved, washed, and reused for filling the joints. The joints were topped up by new clean gritstone where required.

Attempts were made to investigate the maintenance performance of: 1. Blowing followed by sweeping (the current practice) 2. A street sweeper truck 3. A vacuum truck, and 4. An industrial vacuum cleaner.

The general procedure for the trials was as follows: • Permission to perform maintenance trials was first obtained from the site owners.

• Mod-ASTM surface infiltration rates were conducted on the identified PICP test spots.

These results were recorded as base infiltration rates.

• The test spots were surrounded by a shade-cloth fence to protect adjacent property or people from flying debris. The workers wore appropriate personal protective equipment (PPE).

• Maintenance was performed on the test spot using a 700 kPa compressed air blower attached via a flexible hose to a steel “wand” with an 8 mm nozzle. The minimum area of cleaned surface was 2 m x 2 m. The blown-out debris was blown to one side and collected for removal and/or recycling (in the case of the joint gritstone).

• The post-blowing and post-maintenance infiltration rates were then measured to determine the effectiveness of the maintenance.

Laboratory investigation into the link between the upper geotextile, different pavers, and clogging In a bid to better understand the potential for clogging in various geotextile and paver combinations, accelerated laboratory experiments were designed and conducted

IMIESA Jan/Feb 2024

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PERMEABLE PAVING

FIGURE 3: Different types of clogging: I (top left), II (top right), III (bottom left), IV (bottom right)

13 years at the time of testing. This suggests that other factors are far more significant than pavement age in accounting for the deterioration of PICP infiltration performance.

Clogging and Run-on Factor (RoF) The RoF is the ratio of the impermeable area that drains to the PICP to the area of the PICP itself. The higher the RoF, the more the runoff volume is generated and the greater the quantity of sediment deposited on the PICP per storm.

It was expected that the higher the RoF, the lower the infiltration rates would be due to surface clogging. However, no particular pattern was evident in the relationship between the RoF and the infiltration rates measured in the field. Thus, it can be concluded that RoF alone also does not fully explain the clogging rate.

in four HDPE test cells situated in the UCT laboratory to investigate: 1. The link between different geotextiles and clogging with pavers installed 2.

The link between the paver opening and clogging using the same geotextile throughout, and 3. The link between different geotextiles and clogging without pavers installed.

RESULTS Clogging typology Four types of PICP clogging (Figure 3) were identified during the diagnostic assessments: • Type I clogging – the most common type – is when fine material fills the joints, typically the first 20 to 30 mm depth from the surface.

• Type II clogging takes the form of a sediment “wedge” on the bedding layer immediately under the joints and usually looking like a silhouette of the paving pattern.

• Type III clogging is when the bedding layer and the top of any geotextile have been filled with sediment.

• Type IV clogging sees sediment throughout the full depth of the PICP layers (complete failure).

Clogging and age The gritstone placed in the gaps between the pavers acts like a filter trapping fine

30 IMIESA Jan/Feb 2024

particles. While this is of considerable benefit for downstream water quality, these fine particles ultimately clog the pavement (Type I clogging), unless removed. The particles can only go in one of two directions: (i) through physical removal onto the surface, e.g., through air blowing and subsequent sweeping and/or vacuum removal; or (ii) by being driven further into the layers. Here they tend to collect at the base of the openings between the pavers, where they form a “wedge-shaped” mass that inhibits infiltration (Type II clogging).

Traffic movement – particularly on poorly restrained pavers that can move laterally – combined with runoff, can redistribute some of the fines into the bedding layer and clog any geotextile present (Type III clogging).

Ultimately, fine particles may find their way into the base layers, where they fill the openings and reduce the overall porosity and permeability (Type IV clogging).

Given the clear link between the clogging mechanisms and time, it would be expected that the field research would show a clear trend linking age with lower infiltration rates. Unexpectedly, this was not the case.

The research showed very little correlation between age and measured infiltration rates for the eleven sites that date back to the Wits parking area, which had been in operation for

Clogging and paver type Various paver types are available on the market. Tests carried out in the UCT laboratory showed that the rate of clogging largely correlates inversely with the void ratio i.e., the larger the joint openings, the slower the clogging rate.

Clogging and the upper geotextile The upper geotextiles that were installed in high-traffic situations, even when unblocked, were frequently found to be severely damaged even after only a relatively short period (e.g., eight years) of the PICP in operation, and thus unlikely to be fulfilling any function in the system. On the other hand, geotextiles installed in parking bays were generally intact even after more than 13 years of service. Research carried out in the laboratory showed no evidence whatsoever of geotextiles clogging, but this may have simply been because of the experimental method and/or material used.

Clogging and poor paver installation If pavers are not properly installed with adequate edge restraint, they will move – particularly if subject to high turning movements near busy intersections. This allows sediment to easily enter the widened gaps between the pavers from where it is “worked” under the paver layer and into the

PERMEABLE PAVING

bedding layer. If a geotextile is present, Type III clogging is likely. If not, the PICP will eventually fail with Type IV clogging.

new (clean) gritstone in the voids between the pavers.

The SA guidelines Clogging and maintenance Like any pavement, PICP must be maintained if it is to provide the desired level of serviceability over a long period of time. It was apparent from the site investigations that this – at a minimum – requires: • Immediate attention to any structural issues such as widening openings between pavers, rutting, broken pavers, etc.

• Keeping the surface as clean as reasonably possible.

• Ensuring that the gritstone is regularly topped-up to trap sediment before it gets into the underlying layers.

• Periodically blowing out the contaminated gritstone (Type I clogging) and replacing it with clean gritstone.

• Since some material will inevitably find its way to the bedding, it will eventually become necessary to temporarily remove the pavers and bedding, clean them, and replace them – taking care to add

Input from the literature review, the collection of data from existing PICP installations, the laboratory investigations into the role of geotextiles and pavers in possible PICP clogging, and the collective wisdom of the specially created PICP Working Group that eventually included 28 professionals and 31 students – all overseen by the WRC Reference Group of six – culminated in the development of two documents: Guidelines for Permeable Interlocking Concrete Pavements (PICP) in South Africa (TT 913) – Volume 1: Clogging in Permeable Interlocking Pavement (PICP) (Monyake & Armitage, 2023), and Volume 2: Guidelines for the Design, Construction and Maintenance of Permeable Interlocking Concrete Pavement (PICP) in South Africa (Armitage & Monyake, 2023).

The guidelines drill down into best practice PICP design, construction, and maintenance techniques. The Appendices include the Modified ASTM single ring infiltrometer

(Mod-ASTM) test method; the Modified SWIFT (Mod-SWIFT) test method; a template for Details of PICP installation; a template for PICP testing; instructions for diagnostic assessments; and a template for a PICP inspection report.

It is a “living document” – meaning that it can be periodically revised to account for new understanding of the performance of PICP in the field and users are encouraged to communicate with the principal authors in this regard. Overall, it is hoped that its adoption will lead to an improvement in the performance of PICP that will, in turn, increase the resilience of stormwater drainage systems to the impacts of development.

This is an edited version of the paper entitled “The new SA permeable interlocking concrete pavement (PICP) guidelines” presented at the 86th IMESA Conference in October 2023.

The full paper, together with references, can be downloaded by visiting www.imesa.org.za.

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Uniform jointing gaps of 8mm to accommodate the correct jointing material for permeable pavements.

DESIGN WITH PERMEABLE DESIGN PRO Design permeable interlocking pavements with the CMHA’s Permeable Design Pro (PDP) software. The software application deals with structural and hydrological design aspects.

The software now includes rainfall data for 12 major South African cities.

PDP is available for purchase and download from www.bosun.co.za

WATER & WASTEWATER

Water scarcity is becoming a worldwide issue rather than a remote concern.

This is exacerbated by continuous strain on the limited supply of water due to urbanisation, population growth, and the increasing effects of climate change.

GREYWATER REUSE

STANDS AS A PROMISING METHOD FOR FOSTERING WATER CONSERVATION IN GREEN BUILDINGS

A

ccording to the International Water Management Institute, urban water consumption is forecasted to increase from 1995 to 2025 by 62%. With additional increase in population and climate change, water shortage is likely to manifest in 2050.

For these reasons, it has become imperative that we find adaptable solutions in which we can maintain existing water resources while seeking methods in which we can reduce the demand for potable water.

Greywater reuse is receiving more traction as a solution to urban water management as it offers a straightforward on-site but effective option to shift our water-use patterns. Greywater reuse is significant because it may simultaneously address two urgent issues: environmental sustainability and water scarcity. Adopting greywater methods is a critical step toward a

future where we are more water-conscious and resilient. In the face of an unpredictable climate, conservation is a commitment to protecting our most valuable resource.

What is greywater?

Greywater is wastewater that can be reused for other purposes. Greywater makes for as much as 70% of all residential buildings’ water use.

Although greywater and blackwater are typically combined, separating the two, greywater on its own provides several reuse opportunities such as toilet flushing, and garden irrigation. This can additionally assist in lowering potable water use in arid areas by up to 30% for households and up to 60% for corporate buildings. Furthermore, saving money on garden irrigation through reuse can boost household savings by 40%.

Greywater can be collected from the source by installing a plumbing system from an outlet

of a bathroom/kitchen to a garden or for toilet flushing. To this, a greywater treatment system such as wetlands and green walls can be installed to help filter large particles, nutrients and pump treated water through irrigation pipes. Blackwater on the other hand, is toilet water that contains faecal matter and urine. Faecal matter is a breeding ground for harmful bacteria and pathogens that can cause diseases.

Advantages of using greywater for Green Buildings • Water conservation: The use of greywater provides us with an opportunity to use an average of approximately 35-234 litres (per person per day, depending on lifestyles) of greywater, which can be repurposed for garden irrigation or toilet flushing where little human contact is achieved.

WATER & WASTEWATER • Enhancing the EDGE (Excellence in Design for Greater Efficiencies) standard: The incorporation of a greywater reuse system can play a pivotal role in diminishing the reliance on potable water, consequently elevating the overall EDGE score of the Green Building.

• Cost-effective: The use of greywater is inexpensive and for this reason the water bills can be drastically reduced while investing in a greener future.

• Lush landscapes: Watch your garden flourish! Greywater provides essential nutrients such as total nitrogen (2.75 to 21.00 mg/ℓ) and total phosphorus (0.062 to 57.00 mg/ℓ) that mainly originate from the kitchen (kitchen residues/waste) and hand basins (soap), respectively. These nutrients nourish our soil and plants, promoting healthier growth and vibrant blooms.

• Resilience to drought: Water-efficient measures (greywater reuse) make Green Buildings more resilient to water scarcity and drought conditions, ensuring continued operations during challenging times.

Safe and sustainable use of greywater • Greywater has been shown to be a potential hazard to human health. Its handling must be done with care to reduce the risk of infection. Use gloves when handling greywater.

• Greywater containing potentially infectious pathogens should not be used for overhead irrigation. This includes water used to wash nappies or soiled sheets.

• To reduce odour and bacteria, greywater should be used within 24 hours of collection.

• Subsurface irrigation is the best way of watering since it protects against possible microbiological health hazards.

• To avoid waterlogging and prevent root damage, it’s critical to disperse greywater uniformly in your landscape (and not just in one spot).

• When irrigating with greywater, it is not advisable to use spray irrigation. This is primarily due to the increased risk of exposing people to greywater.

• Where possible, greywater should not be used for an extended period in the same area. This may result in the accumulation of different components found in greywater that may negatively impact the plant’s health.

Rand Water is still upholding its commitment to encourage watersaving behaviours among its supporting clients in its service region by using the Water Wise brand. #WaterWise Images sourced from: https://pbs.twimg.com https://epiccleantec.com https://www.gwig.org/greywater-regulation

Visit www.randwater.co.za and click on the Water Wise logo or contact us on: 0860 10 10 60

Automation can help bridge WWW skills gaps

By Peter Marumong

S

outh Africa’s water and wastewater (WWW) sector faces key challenges that include poor maintenance, recurring droughts driven by climatic variations, inequities in access to water and sanitation, deteriorating water quality and a lack of skilled water engineers.

The above are well-known, each adding to the country’s water crisis challenges. In the case of skilled water engineers, or lack thereof, the challenge is compounded by factors such as an aging workforce, limited educational opportunities, and low industry attractiveness. Here, automation and technology can provide some relief, and while it is not the silver bullet to eliminating the country’s WWW skills shortage, it can provide utilities and operators with the necessary tools to alleviate some of the immediate concerns.

Evolution instead of revolution Automation offers native IT/OT integration, thus eliminating the need for complex gateways. This lends itself to a user-friendly system that benefits all stakeholders, including engineers, plant operators, systems integrators, and machine builders.

Furthermore, designs can be virtually simulated and tested before deployment, and once it’s defined as a digital asset, it can be “dragged and dropped” in the user interface. Also, through automation, maintenance and troubleshooting are streamlined as the information remains up to date throughout an asset’s lifecycle.

Access to updated information also improves overall uptime and reliability.

The mean time to repair is shortened, as technicians no longer need to search through multiple sources for the data they need.

Significantly, automation solutions don’t require an all-or-nothing approach.

WWW operators can deploy it on a smaller scale, preserving current investments and minimising training needs. The “wrap and replace” approach allows existing and new systems to run together, gradually scaling up as financial benefits become apparent.

Core advantages Key benefits include: • Enhanced efficiency: automated control systems continuously monitor water treatment processes, optimising parameters and adjusting operations in real-time. This reduces the reliance on skilled personnel to manually oversee complex processes.

• Additionally, remote asset monitoring enables experienced professionals to provide support and guidance to less experienced workers from afar.

Ultimately, this integration of automation and skilled personnel play an important role in narrowing WWW efficiency gaps.

Peter Marumong, Cluster WWW Segment Leader at Schneider Electric

IMIESA Jan/Feb 2024

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WATER & WASTEWATER

Water infrastructure managers want efficient and sustainable operations.

They need to see what is happening across their sites. Yet this is challenging because old software and obsolete data analytics deliver underwhelming operational visibility. By Chetan Mistry

C

ENHANCING WATER MANAGEMENT WITH CLOUD TECHNOLOGIES

loud technologies can help managers reach those goals, optimising operations and ensuring potable water. When managers want predictive maintenance, real-time alerts, or remote management, the best results are almost exclusively through the cloud.

Nonetheless, they have many questions and many water managers are not sure if they should use cloud technologies. There are also numerous myths and misconceptions about the cloud, which is a pity because cloud systems enhance and modernise water operations. People should tr y to understand the cloud and challenge these misconceptions, but we can’t blame them for

being reluctant because they are the ones sticking their necks out to bring the cloud in.

So, what are the fundamentals of the cloud, and why are cloud solutions well-suited for water infrastructure management?

The cloud, data and security The cloud radically increases returns while reducing up-front investment costs. Through the inventive use of modern software, cloud systems combine and scale multiple servers to deliver cutting-edge digital, data and artificial intelligence services across the internet at very competitive costs.

Traditional IT cannot do this without incurring enormous

Chetan Mistry, Xylem Africa’s Strategy and Marketing Manager

34 IMIESA Jan/Feb 2024

expenses and upfront investment. Typically, a site would purchase software and long-term user licences, and purchase and maintain the hardware and human skills that run that software. However, this traditional approach has considerable drawbacks.

Foremost, it takes time, money and skills to maintain the hardware. Second are costs incurred for software maintenance, updates, and patches. Third, the software is isolated to a specific location – people must be on-site to use it. And lastly, the

WATER & WASTEWATER

software has no natural ability to scale cost-effectively. Water sites are stuck with what they bought and have to “sweat” the software, even if it’s outdated and lacking new features.

Cloud computing turns this approach on its head. Sites don’t need to purchase software or licences—they access on a pay-permonth or pay-per-use subscription model. The cloud service provider owns and runs the servers hosting the software. Patches and updates are applied proactively and at no extra cost to customers.

Remote and scalable As the cloud is a native internet technology, cloud software is remotely accessible. Cloud business models use platforms that scale, so the cloud ser vice can shrink or expand as needs and budgets change. Cloud software also increases security: while customers must continue to create healthy security practices, cloud providers invest extensively in security features, industr ystandard frameworks, and data protection standards such as ISO 27001 and SOC 2 Type II. Fur thermore, the cloud de-risks software usage, lowers associated costs, and provides more flexibility. Yet site managers don’t lose any control. They still manage their data, compliance, and security. But they let go of cost and management elements holding them back, passing those to cloud partners with serious resources, skills, and innovation capacity.

Choosing the right partner The cloud can relieve water management from outdated systems and technology stagnation. Trust is the cloud’s currency; water sites should focus on selecting partners that will stick with them.

If a cloud company is primarily trying to sell a product to you, walk away. You are not buying a product – you are buying into a relationship. They need to demonstrate that they listen and can assess your needs for proactive solutions. They must also demonstrate that they know your sector and they continually invest in their systems for your benefit.

Take cybersecurity as an example. Serious par tners offer security assessments and back solutions with real-world use cases and customer stories. They follow best-practice security frameworks, earn and maintain standards such as ISO 27001 data protection, and align with the top cloud vendors, such as Amazon and Microsoft.

A sustainable solution for clearing blockages and cleaning conduits

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n the midst of tight economic constraints and water scarcity challenges, maintenance teams are increasingly seeking innovative solutions that can work more efficiently and save on time, money, and resources. This includes the approach to unblocking and cleaning sewer lines, stormwater drains and sewer pump stations, among other applications.

To meet this requirement, Werner Pumps, a leading manufacturer of highpressure jetting equipment and industrial vacuum solutions, has designed a special truck-mounted recycling jetting and vacuuming unit.

These trucks are particularly appealing for municipal maintenance teams as they allow them to solve a range of blockage and drainage issues, from the simple to the complex, using a single piece of equipment. “Our water recycling unit can save up to 168 000 ℓ of clean water in each 8-hour shift,” explains Sebastian Werner, managing director at Werner Pumps, adding that due to its contact-free rotor design, the onboard vacuum pump is extremely quiet, which makes it effective when working in residential areas.

Rand West order Recent orders include the delivery of a unit to Rand West Municipality in Gauteng, which is one of the first municipalities in South Africa to invest in this type of equipment. Werner Pumps has since received an order from Rand West Municipality for a second unit.

Werner Pumps also supplies a wide variety of accessories for its units, including high pressure guns with lances, high pressure jetting hoses (20 m, 30 m or 50 m), low-water inlet switches, nozzle holders and fan nozzles.

“We work with our customers to help them solve their high pressure jetting and vacuuming needs and can advise on how best to service particular applications,” Werner concludes.

Conclusion Xylem knows that cloud computing is a game-changer for water management. But we also appreciate that there are concerns about risks such as control, security, maintenance, and cost management. To answer these needs for our customers, we develop and maintain policies, skills and partnerships to counter risks and boost value.

Whether the concern is about data breaches, data sovereignty, cloud skills, or aligning cloud technologies with water strategies, we do the heavy lifting so that water sites can focus on their core priorities.

The technology is academic—it’s the partner’s job to listen to your needs and respond with the right solutions. It doesn’t make sense to stay in the past with outdated systems.

Sebastian Werner, managing director of Werner Pumps (left) and Thinus Prinsloo, fleet supervisor at Rand West Municipality, celebrate the delivery of the municipality’s first truck mounted recycling jetting and vacuuming unit

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PUMP TECHNOLOGY

As a leading original equipment manufacturer (OEM) since 1952, APE Pumps and group entity, Mather+Platt, have achieved ongoing market penetration through extensive investments in technology and skills.

IMIESA talks to sales engineer, Neil Richards, about their latest round of machine acquisitions, which now enables the group to offer a complete in-house ser vice.

The horizontal boring machine is ideal for the final machining of larger impellers, which typically measure around 3m in diameter. Seen here is a wear ring

A TOTAL PUMP SOLUTION 1

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1 The group’s new centre lathe is equipped to handle jobs ranging in lengths of up to 8m and in varying diameters for components such as columns, shafts, and impellers 2 A technician carries out a laser inspection to verify that the machined casting is 100% in accordance with the designed tolerances 3 The vertical boring machine is employed for the machining of split casings 4 A CW pump impeller measuring some 3m in diameter 5 Neil Richards, sales engineer for APE Pumps and Mather+Platt

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s the leaders in pump innovation, the group has always been central to the critical mechanical engineering processes needed to keep mainstream industry running in all areas where fluid transfer is an essential requirement.

Examples include agriculture, mining, water, wastewater, the petrochemical sector, and power generation,” says Richards.

“If anything, the demand for these specialised solutions has grown in South Africa due to the changing local manufacturing landscape.

This has seen a general contraction in foreign and local

PIPE SYSTEMS investment post COVID-19, with business closures, and growing technical skills gaps,” he continues.

“That’s why we’ve invested in additional machinery updates at our Germiston plant so we can eliminate our reliance on third parties for most stages of pump fabrication, beyond the foundries for our component castings. This development underscores our commitment to the market, providing absolute assurance that we are invested for the long-term, with full inventory support.”

Lead times are key Turnaround times are crucial – whether for new pump delivery, repair or refurbishment – especially for customers who run mission critical, 24-hour a day operations. “With everything now available on our floor, we can take efficiencies to new heights because we have full control over lead times and quality.

There are few other pump OEMs in South Africa that have this capability,” Richards explains.

Examples of critical components that can now be fabricated completely in-house include the group’s CW pump range. These are used in applications that include cooling towers.

Technology that works The four machines added to the group’s production line are a centre lathe equipped to handle jobs ranging in lengths of up to 8m and in varying diameters for components such as columns, shafts, and impellers; a key slotter for keyway cutting (a drive system feature on one of the group’s impeller lines to enable rotation around the shaft); as well as a horizontal and a vertical boring mill.

The horizontal boring machine is ideal for the final machining of larger impellers, which typically measure around 3m in diameter.

This includes elements like wear rings, and back covers. In turn, the vertical boring machine is employed for the machining of split casings.

3D scanning The group’s engineering team conducted in-depth research to ensure that the Germiston plant now has the optimum manufacturing setup for the extended line. Last year, the group also invested in a cutting-edge 3D laser scanner, which has fast become an invaluable tool. Applications include quality management – verifying the final machined tolerances with 100% accuracy against the original design; condition assessments before a rebuild; as well as for installation and commissioning.

“Thanks to the onboard software, comprehensive reports can also be generated for the clients’ engineers, which provides an added level of quality assurance,” Richards concludes.

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SAPPMA ELEVATES PLASTIC PIPE MANUFACTURING STANDARDS The Southern African Plastic Pipe Manufacturers Association (SAPPMA) is proud to announce the launch of Project Superior Quality 2024, underscoring its unwavering commitment to upholding the highest standards in the region, where it plays a pivotal role.

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an Venter, CEO of SAPPMA, emphasises the urgency of addressing long-standing challenges related to suspect quality, particularly concerning HDPE pipes. He explains that factors such as the use of third-party recycled material, price-cutting, and inadequate official certification have contributed to this persistent issue.

“Maintaining superior quality has always been the foundation of the SAPPMA brand. Project Superior Quality 2024 is our comprehensive response to the rising incidents of suspect quality, reaffirming our commitment to excellence in the plastics pipe industry,” Venter explains.

Key measures under Project Superior Quality 2024 include: Stricter standards: immediate adoption of the latest SANS ISO 4427:2023, with an increased OIT (Oxidation Induction Time) test value of 30 minutes at 210°C and a maximum 20% shift in OIT value from raw material to the final product.

Enhanced monitoring: increased frequency of sampling and testing through unannounced factory audits, ensuring compliance with the revised standards.

Code of Conduct amendments: strengthening the existing Code of Conduct signed by member companies; aligning it with the updated quality standards.

Advisory Committee restructuring: the Advisory Committee has been restructured into four different market sectors, allowing for more focused attention and expertise.

Disciplinary Committee establishment: a dedicated Disciplinary Committee – free from conflicts of interest – has been established to handle deviations from the Code of Conduct, ensuring accountability.

Industry collaboration: increased interaction with consulting engineers, municipalities, and contractors to promote awareness and understanding of product quality.

Public awareness campaign: a focused promotional campaign in the media aimed at informing the public about the industry’s commitment to superior quality.

Venter expresses confidence in the success of the initiative, citing the full support of the Board of Directors. He emphasises that it’s the collective responsibility of all members to ensure that Project Superior Quality 2024 is a resounding success.

“We invite all stakeholders to join hands with us in this crucial endeavour, which underscores the significance of maintaining high-quality standards for the benefit of the industry, market, and public,” Venter concludes.

Visit www.sappma.co.za for more information.

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ROADS & BRIDGES

Rehabilitating the Sarnia Road Bridge Located within eThekwini municipality between the suburbs of Bellair and Hillary, the Sarnia Road Bridge (B112) is a strategic conduit that runs over the N2 and carries traffic along the M10 route.

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familiar sight for many motorists, the bridge incurred significant damage in 2017, especially to the underside of the structure, when a vehicle accident took place on the N2 northbound carriageway, resulting in a tanker truck catching alight directly beneath it.

The South African Roads Agency Limited (SANRAL) put the project out to tender in 2022, with the scope of work listed as N002-250-202/3-The rehabilitation of B112, Sarnia remedial.

Local constr uction company, Afrostructures, which specialises in structural concrete, building, and development, emerged victorious after a competitive bidding process. Located in KwaZulu-Natal, with a grade 9CE and a level 1 BBBEE rating, the industry leader secured the contract in April 2022.

Naidu Consulting was contracted to oversee all engineering works and supervision of the project, while specialist company, Structural Maintenance Works, was to handle the fire damage repairs, spalling, and coating of the bridge.

Under the careful consideration of this team of experts, the project got underway.

38 IMIESA Jan/Feb 2024

REFURBISHMENT PROCESS Step 1: High pressure cleaning (350 bar pressure) A high pressure clean at 350 bar pressure was conducted to remove debris and compromised concrete and prepare for restoration.

Step 2: Sounding survey A sounding sur vey was under taken to assess concrete integrity. This precision test streamlined the process and ensured that only compromised sections were addressed.

Step 3: Exposing sound undamaged concrete All fire damaged concrete was broken out to expose undamaged sections. This selective approach minimised reconstruction needs, which in turn reduced the cost and environmental impact.

Step 4: Rebar preparation and substrate dampening The exposed rebar was meticulously cleaned, and the substrate pre-dampened for a strong bond, ensuring subsequent layers would adhere securely.

All fire-damaged concrete was broken out to expose undamaged sections. The exposed rebar was meticulously cleaned, and the substrate pre-dampened for a strong bond, ensuring subsequent layers would adhere securely

Step 5: Application of structural repair mortars Following substrate preparation, Sika MonoTop®-1010 ZA was brush applied to both the rebar and the substrate as both a protective coating for reinforcing steel, and a bonding agent. This cement-based slurry contains recycled materials, which leads to a reduced carbon footprint. As a bonding primer, it offers reinforcement corrosion protection.

ROADS & BRIDGES

Once the primer had cured, Sika MonoTop®-412 NFG – an R4 repair mortar with a corrosion inhibitor – was applied using a wet spray method.

Due to concerns about bridge flexing under live loads, it was imperative that this phase be completed in a single day. This was made possible by dividing the work into sections, each spanning approximately 2 m across the width of the bridge (± 15 m long).

Step 6: Spalling repairs It was found that small sections of the bridge required spalling repairs.

Due to chloride ingress, the substrate preparation process mirrored the one above, with a minor adjustment of Sika MonoTop®-412 NFG being trowel applied to affected areas. Where more extensive repairs were required, a shutter-andpour method was employed using Sikacrete®-214, a cementitious, high, early strength structural micro-concrete.

Step 7: Addressing concrete blistering There was evidence of concrete blistering in the centre of the bridge, where the heat of the fire had been less intense. This was addressed using the same preparatory steps, after which Sika MonoTop®-3020 ZA – an R3 cementitious pore filler and levelling mortar with a reduced carbon footprint – was meticulously trowelled on in a 1-5 mm thick layer.

PROTECTIVE COATING SYSTEMS Step 1: Corrosion protection Sika® FerroGard®-903 Plus was applied via low pressure spray method to

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AFTER

The bridge soffit before and after remediation. Sika® FerroGard®-903 Plus was applied via low pressure spray method to the entire bridge soffit. This coating delays corrosion and reduces the future corrosion rate

the entire bridge sof fit. This coating delays corrosion and reduces the future corrosion rate.

Step 2: Chloride and carbonation protection The abutments, piers, and sides of the bridge received the Sikagard®-550 W Elastic system. This comprehensive system consists of one coat of Sikagard®-550 Elastic Primer and two coats of Sikagard®-550 Elastic, a crackbridging protective coating for concrete, which enhances durability and protects the structure against chloride and carbonation ingress.

Step 3: Protection against graffiti To deter vandalism and protect the aesthetics of the bridge, Sikagard®-850 AG, an anti-graffiti coating, was applied.

This final touch ensures that the lower

3 m of the two abutments and the pier on Palm Drive remain in pristine condition and any graffiti applied will easily wash off with water.

This project would not have been possible without the wealth of knowledge and expertise of the contractors involved. SIKA was honoured to be able to contribute to the successful rehabilitation of the Sarnia Road Bridge (B112).

The completion of this project contributes to the safety and functionality of the bridge and the overall transportation infrastructure in the area and, perhaps even more importantly, it demonstrates that even in the realm of rehabilitation, there’s room for innovation and improvement. Throughout the tender period, the new COTO draft specifications (October 2020) were adhered to, reflecting a firm commitment to the latest industr y standards and best practices.

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AFTER

The abutments, piers, and sides of the bridge received the Sikagard®-550 W Elastic system

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ROADS & BRIDGES A computer generated rendition of the Msikaba Bridge

MSIKABA BRIDGE

REACHES NEW HEIGHTS The 580 m long cable stayed Msikaba River Bridge forms part of the South African National Roads Agency’s N2 Wild Coast Toll Road project and once completed will cross the Msikaba River Gorge at a height of 192 m.

The north and south pylons for the Msikaba Bridge under construction (October 2023)

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esigned by the HVA Joint Venture (of which SMEC South Africa is the main partner), this mega bridge is being constructed by the Concor Mota-Engil Joint Venture, with SMEC South Africa responsible for the construction supervision of the project.

One of the key aspects of the bridge is its two identical, inverted Y-shaped, reinforced concrete pylons. Each 127 m tall pylon comprises two inclined legs, straddling the roadway below, and a tall cylindrical spire. The spires have a diameter of 6 m at the bifurcation, where

40 IMIESA Jan/Feb 2024

South pylon construction (November 2023)

the two legs meet, tapering to 4,5 m at the top.

The bridge’s four anchor blocks were completed by the end of 2023, while all five of the tributary structures have also reached completion. The latter comprise three reinforced concrete drainage culver ts (ranging between 67 m and 100 m in length), one reinforced concrete pedestrian culver t and one 32 m long, three-span integral reinforced concrete bridge.

Erection of the deck is scheduled to commence in the first quarter of 2024 in parallel with the ongoing construction of the pylons, which had reached a height of around 80 m by the end of 2023.

Anchorage points According to the design, anchored into each pylon are 17 pairs of main stay cables (connected to the deck) and 17 pairs of back stay cables (anchored 130 m behind the structure). The cables are anchored by means of 17 internal structural steel anchorage liners starting at a height of 88 m.

These liners form a critical part of the structural system as they transfer the loads generated by the superstructure through the stay cables and down into the pylon shafts. The mechanism of load transfer between the steel anchorage liners and the concrete pylons is through shear stud connectors. Each 2 m tall liner has approximately 400 shear studs and weighs approximately 10 t.

ROADS & BRIDGES

Typical pylon liner under fabrication

The largest liner at the top of the pylon transfers a total of 1 400 t from the pair of main span and back span cables to the pylon. The combined load from all of the liners results in a load on the pylon of more than 20 000 t at the top of the pylon inclined legs.

Liner fabrication The liners are being locally manufactured off-site in a facility in Witbank. Once

3D model of a typical structural steel pylon anchorage liner and cross section showing their installation sequence

delivered to site, they will be installed into position using a tower crane.

With a construction tolerance of 10 mm, it is important that the liners fit perfectly upon installation. Adjusting the heavy liners at these heights will be a challenge.

In addition, the alignment of the stay cable anchor positions is critical to the success of the project.

Given the length of the cables (between 185 m and 308 m), the slightest offset

on the anchorage position in the pylon will result in large offsets at the opposing anchorage positions located in the deck and anchor blocks. Therefore, before the liners are transported to site, they are pre-assembled at the fabrication yard and surveyed to ensure fit-up and alignment.

The first liner is scheduled to be installed during the first quarter of 2024 with the rest following sequentially as the construction programme progresses.

RECYCLING AFRICA’S ROADS

RECYCLING AND BUILDING

NEW ROADS WITH ASTEC Founded in 1972, Astec Industries Inc. (Astec) is an American original equipment manufacturer (OEM) headquartered in Chattanooga, Tennessee, and currently fields 16 brands across an extensive global footprint, with some 100 products produced in 25 facilities worldwide. Alastair Currie speaks to Philip Saunders, regional sales manager and product specialist for Astec Infrastructure Solutions in South Africa about key models in their road construction line-up.

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The SB-3000 uses a triple pitch auger design to eliminate segregation issues caused by single pitch augers

he solutions in the road portfolio are extensive, encompassing pavers, material transfer vehicles (MTVs), cold planers, soil stabilisers and asphalt reclaimers, asphalt brooms and cold in-place recycling machines – all falling under the Roadtec brand. All model frames are manufactured with A656 grade 80 steel, providing around twice the tensile strength of industry standard steels commonly used by OEMs, but with no added weight.

Allied to this are integrated portfolios that include Astec’s asphalt plant range (modular and static), as well as

42 IMIESA Jan/Feb 2024

its speciality plants and terminals for bitumen storage. Beyond that are a comprehensive series of complementary products that include crushing and screening, and concrete plants to provide the market with what the OEM refers to as a Rock to Road® model, along with proprietar y Guardian® intelligent telemetry connectivity.

“As an OEM we provide niche solutions for regional road markets and have a long-established presence in South Africa dating back many decades for all phases of road rehabilitation, as well as new construction,” says Saunders.

Shuttle Buggy “Locally, the Roadtec range – first introduced in the USA during 1981 – remains an industry stalwart among leading contractors. Here one of our best sellers is the Shuttle Buggy® MTV series, the default choice for one of the most crucial phases of asphalt surfacing – feeding the paver in a seamless process,” Saunders continues.

“The latest rendition popular in South Africa is the SB-3000 model, designed with an approximately 27 tonne remix capability, which replaces the previous generation SB-2500 unit globally,” Saunders continues.

A key advantage of MTVs is that they greatly reduce truck off-load waiting times and the incidence of stationary pavers waiting for feed. “Loading from a truck directly into a paver is not the recommended route.

The stop start nature of this transaction means there’s an increased chance that temperature changes will occur, resulting in a cooling asphalt mix that raises the risk of poor pavement quality finishes due to segregation,” says Saunders.

The optimum technique is to load into the MTV, which continues to maintain the correct asphalt design temperature while constantly feeding into the advancing paver’s hopper bin. This enables nonstop paving, resulting in the best possible mat.

Cold planers as a greener alternative For road upgrades, the process starts with the milling of the existing asphalt, which in today’s market has the added advantage of incorporating recycled asphalt pavement (RAP) methodologies that promote sustainable reuse. Enter the Roadtec RX series, available in either half lane or full-lane models and equipped with the optional automated Ace™ Grade and Slope Control System. Partial or fulldepth milling is possible, depending on the extent of the rehabilitation required, as well as the working width specification.

A key model within this series is the midrange RX-600e with its maximum 2,18 m milling width, cutting to a maximum depth of 330 mm. A two-stage front load-out

RECYCLING AFRICA’S ROADS

Eight cutting speeds and right-hand flush cut make the SX series the ideal choice for a range of projects, including stabilising or cold recycling

conveyor, with a 60° swing to either side, provides ample loading capacity.

The track assembly configuration comes in two variants: three-track suspension provides greater manoeuvrability in the cut and is lower in weight, while four-track machines enable higher tractive effort and flotation.

A new entrant on its way to the South African market is the RX-505e, following its introduction in North America, where it has been field-proven and refined based on customer feedback over the past 24 months. It shares many common features with the RX-600e, including maximum cutting depth and conveyor angle capabilities, with the added advantage of improved machine controls.

Soil stabilisation and full depth reclamation At the heart of any road is the foundation for the final riding surface, and here dual purpose Roadtec soil stabilisers and asphalt recyclers make sure the underlying layer works suppor t the transportation engineering design.

An industr y-exclusive air-shift transmission allows the operator to shift the rpms on the specified cutter drum to suit the application. Additionally, all units are fitted with hydraulically controlled suspension, which enables the depth of cut to be selected at the touch of a button.

Within the mix for the South African market is the Roadtec SX-6, equipped with a high performance 6-cylinder diesel engine that provides power to the rotor through a direct drum drive, and capable of cutting up to a depth and width of

508 mm and 2,438 mm wide, respectively, for in-situ sub-base reclamation and cement stabilisation.

This machine is configured with a dual pump set-up for water and/or emulsion.

In single pump mode, the machine is capable of delivering up to 2 000 litres per minute.

Asphalt plants Along with paving train options, for wellestablished contractors looking for a turnkey solution there’s the added advantage of incorporating either an Astec modular or static plant, or both.

For specialist asphalt manufacturers, the same business case applies.

Within its modular asphalt plant range, one of Astec’s most popular product lines is the BG Series catering for tonnage outputs between 80 and 280 tph. These batch plants are sold in containerised configuration for low-bed transportation and offer up to 70% RAP capabilities.

For South African contractors, the BG 1800, with its 140 tph capacity (depending on altitude), meets most local requirements. As with other plants in the series, it can be supplied in skid-mounted configuration for fast set-ups without the need for an established foundation.

Then for static, long-term installations, products include the Astec M-Pack™ series, which provides a relatively fast erection time with “bolt-on” solutions.

Each M-Pack plant comes with full-size control rooms, and large silos for ensuing high production capacity – designed like its modular counterparts for hot-mix and warm-mix asphalt products.

Within its modular asphalt plant range, one of Astec’s most popular product lines is the BG Series catering for tonnage outputs between 80 and 280 tph

The RX-600e is set-up for a maximum 2,18 m milling width, cutting to a maximum depth of 330 mm. A twostage front load-out conveyor, with a 60° swing to either side, provides ample loading capacity

The road ahead “Worldwide, we have customers that select specific models for their mixed fleets or transition to a full Roadtec road train.

Locally, we see major opportunity for both scenarios given the upswing in SANRAL project awards – along with the entry of new contractors – on developments that include the N3 upgrade between Pietermaritzburg and Durban, as well as the KwaZulu-Natal North South N2 corridor,” says Saunders.

To suppor t new and established contractors, Astec provides a range of flexible finance options for customers.

These include traditional hire purchase type agreements financed through local banks; a blend of internal OEM and external retail bank finance; as well as rental options with an option to purchase.

Machines are sold direct to market, as well as via a progressively expanding dealer network.

“While the Astec range is high-tech, the OEM’s R&D team have focused on maximum operator simplicity, as well as ease of maintenance to lower lifecycle ownership costs and keep availability at the highest level possible. Across the world, the Astec machine population keeps growing, with a similar trend experienced in our South African market,” Saunders concludes.

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1013041

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BITUMEN & ASPHALT

Guatemalan contractor adds larger Lintec CDP14001M plant A 40 000 litre bitumen tank and 20 000 litre fuel tank ensure that the Lintec CDP14001M can operate self-sufficiently

With an area of 370 m2, the Lintec CDP14001M’s baghouse filter ensures a low rate of particulate emissions, aiding compliance with local environmental emission regulations

Guasueca S.A., one of Guatemala’s leading equipment dealers, recently sold one of its customers a second continuous asphalt mixing plant from Lintec & Linnhoff. The Lintec CDP14001M joins the customer’s existing Lintec CDP5001M, the smallest in this range

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he plant was immediately dispatched to suppor t road rehabilitation projects in Cobán, central Guatemala, over 200 km from Guasueca’s HQ in Guatemala City.

Cobán is Guatemala’s four th largest city and a popular eco-tourism and coffee growing area, set at an elevation of 1 320 m. It is exposed to a constantly humid climate and has a high chance of rainfall on any given day, making working conditions variable and uncer tain. Here over a period of eight months, the Lintec CDP14001M will per form a road rehabilitation role on a 5 km section of the Oce-003-2022 road network right in the hear t of this busy city.

“The customer’s prior experience with the Lintec CDP5001M gave them confidence in the superb mobility and high productivity of Lintec plants. So, they had no hesitation in selecting the

Lintec CDP14001M for this impor tant project to improve traf fic flow in Cobán’s urban areas,” explains Jaime Sales, general manager at Guasueca.

“The customer also appreciates how easy it is to move this compactly designed plant to different projects. It is an ideal choice for congested locations and delivers effortless production of up to 140 tonnes of high-quality asphalt ever y hour.”

Quick, easy and self-sufficient The Lintec CDP14001M continuous asphalt mixing plant is conceptualised for quick, easy set-up and dismantling, including the ability to be assembled on compacted ground without the need for concrete foundations. It is particularly well-suited for shor t-term projects or mobilisation from one project to another.

As the second largest model in Lintec’s mobile CDP range,

it is also per fect for stationar y use, with the possibility of integrating either three 6 m3 or four 7,5 m3 aggregate bins to tailor the configuration to local conditions. A 40 000 litre bitumen tank and 20 000 litre fuel tank ensure it can operate self-sufficiently.

Production of the finest quality hotmix asphalt is ensured using the latest automatic control system software with manual override, along with the robust and durable twin-shaft mixer that enables precise, repeatable output.

With an area of 370 m2, the Lintec CDP14001M’s baghouse filter ensures a low rate of particulate emissions, aiding compliance with local environmental emission regulations. A fur ther environmental benefit comes with the option of a cold recycling system that can use up to 15% of reclaimed asphalt pavement (RAP) material, conser ving natural resources.

The Lintec CDP14001M continuous asphalt mixing plant is conceptualised for quick, easy set-up and dismantling

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VEHICLES & EQUIPMENT

KOBELCO EXCAVATORS IMPRESS AT RAUBEX Two 38 t Kobelco excavators are fast justifying their purchase by one of South Africa’s most well-known multidisciplinary construction companies and, in doing so, proving their acquisition and subsequent application to be the correct decisions

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aubex was established in 1974 and through steady growth listed on the Johannesburg Stock Exchange (JSE) in March 2007 as the Raubex Group Limited.

The company is one of South Africa’s leading infrastructure development and construction materials supply groups. It’s a dynamic organisation that has moved with the times as its Level 1 BBBEE rating shows and, with more than 8 000 employees, the company is focused on ensuring high levels of integrity, professionalism, and quality in all that it does and produces. Raubex operates throughout Southern Africa and Western Australia.

Raubex Construction is a major part of the Raubex Group and has the construction of roads and various infrastructure projects as its core business. This work includes new road construction, the rehabilitation of existing roads, bridges, dams, tailings dams for mines and many other challenging civil engineering projects.

Being a civil engineering concern, the company runs a substantial fleet of yellow machine equipment. Some 23 years ago, Raubex Construction established its mechanical workshops in Bethlehem in the Eastern Free State and it’s here that we find Bennie Burger, the company’s senior plant manager.

“You may find it strange that we established our mechanical workshops here in Bethlehem and not in a major centre, but the thinking was that due to the relatively remote areas where we sometimes work, especially when working on road construction, Bethlehem is quite centrally situated and many of our projects are easily accessible from here,” he says. “We employ 65 people in total, which includes administrative staff, qualified diesel mechanics, people in the

parts department, stores, and operators. The mechanics go out to render field ser vicing and repair when machines can’t be brought to the workshop.”

“When doing work on state contracts, wherever that may be, we generally have to hire equipment and labour to the value of 30% of the total contract value from local communities in the immediate vicinity of the project and this often sees the gap being filled for small plant like rollers and backhoe loaders.”

Comprehensive fleet and acquisition strategy Raubex’s fleet of constr uction and earthmoving equipment is substantial and comprises graders, recyclers, dozers, wheel loaders, tipper and water trucks, articulated

Raubex’s senior plant manager, Bennie Burger (left) with Bell Equipment sales representative, Chris Botha

VEHICLES & EQUIPMENT dump trucks, rollers and excavators. The company believes in obtaining the maximum life out of any piece of equipment and when that machine life is deemed to no longer be economically viable, the equipment is sold out of hand with a complete service history.

“We recently needed to add two machines to our excavator fleet in the 40 t class and while researching the market we came across Kobelco excavators, which we saw are distributed in South Africa by Bell Equipment,” Burger explains.

“Although our subsidiary company B & E International has run these and heavier Kobelco excavators successfully, Raubex had never owned any models of this Japanese brand until we spoke to Chris Botha, the Bell Equipment sales representative who visits us diligently and we found out more about this seemingly great brand of excavator.”

Raubex Construction needed two excavators. One would be deployed on a major road rehabilitation project, which would see the machine loading blasted quarry rock for processing into aggregate and the other would be fitted with a hydraulic hammer on a bridge project during a further phase of the Lesotho Highlands Water Project.

“Everything seemed right for us to choose the two Kobelco SK380XDLC-10 excavators as Bell Equipment had stock of the two machines at a competitive price and they had the correct hydraulic piping for us to fit a hydraulic hammer, albeit from a third party,” Burger continues. “We were also impressed with the reinforced undercarriage and buckets on the machines, which we then duly ordered and received in June 2023.”

Local bucket fabrication Bell Equipment manufactures all medium and large excavator buckets for the Kobelco excavators it sells locally, and these buckets fit South African conditions, given that the machines are often used to load dense and abrasive mined material and blasted rock.

Burger mentions that since both machines started work on their respective sites, both have performed admirably with no reported downtime in their first 1 000 hours of service. An average fuel burn of 18,4 litres an hour has been a pleasant surprise and fits the business plan of both projects.

“While we acknowledge that our first two Kobelco SK380XDLC-10 excavators are still new, we’d like to imagine that given their present impressive performances – with frugal fuel burn as a bonus – we’ll be adding more of these machines in their distinctive turquoise livery to our fleet,” says Burger.

“And knowing that Kobelco excavators are backed up by Bell Equipment, a company with its own established wide national and cross-border footprint, trained personnel, and proven parts holding, will provide a winning combination that will be hard to beat,” Burger concludes.

NEW CEO FOR

BELL EQUIPMENT Bell Equipment Limited has appointed Ashley Jon Bell (41), grandson of the company’s founder Irvine Bell, as the new Group Chief Executive Officer (CEO) effective from 1 January 2024.

Ashley is well acquainted with the company having served as a non-executive director on the Board since March 2015 and has provided valuable input as a member of the Board’s Risk and Sustainability and Social, Ethics, and Transformation committees.

A qualified commercial helicopter pilot, Ashley holds a degree in business management and has previously worked for Bell Equipment after graduating in 2007, assisting with product marketing management of the Bell articulated dump truck and backhoe loader ranges.

Since then, he has jointly established and managed several successful businesses in various industries.

He also co-founded Matriarch Equipment with his brother, Justin Bell in 2009. The company focused on developing innovative equipment for a wide spectrum of industries and enjoyed notable success in agriculture and forestry due to its “customer-centric” approach and quick turnaround of niche solutions. Bell acquired Matriarch in 2019 as part of its strategy to revitalise its presence in the agriculture and forestry industries and its products now fall under the Bell brand.

Gary Bell, non-executive chairman of Bell Equipment, congratulated Ashley on his appointment. “Ashley joins a sizeable team representing the third generation of the Bell family actively engaged in the business and it’s heartening to see the next generation stepping up to play an integral role in the future of the company. Having worked closely with Ashley for several years he has all the personality traits and credentials we need, is well aligned with the board’s strategy, and is a good fit to lead our experienced management team. I have every confidence that he will build on our family legacy with dedication and a passion for the business.”

Comments Ashley Bell: “I am fortunate to have grown up in an environment where Bell Equipment has been a central theme, and I am both honoured and excited to step up as Group CEO. I look forward to working with the entire Bell team, supported by our customers and suppliers, to ensure we execute our group strategy and make a positive impact for all stakeholders. I would like to extend my sincere thanks and appreciation to the board for the trust and confidence they have shown in me taking on this role.”

Ashley Bell, CEO, Bell Equipment Limited

IMIESA Jan/Feb 2024

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87

TH IMESA

2024

CONFERENCE

IMESA

CONFERENCE ENGINEERING REVOLUTIONISED

ENGINEERING REVOLUTIONISED

CAPE TOWN 6-8 NOVEMBER

06 - 08 November 2024 CAPE TOWN | GRANDWEST

call for abstracts CATEGORIES

• Buildings, Structures

• Electrical and Electronic

• Ecological, Environmental

• Water and Sanitation

• Financial, Legal

• Transport, Roads and Stormwater

and Housing

and Social

and Regulatory

A B S T R AC T S S U B M I T T E D BY

10 April 2024

marketing@imesa.org.za | tel +27 (0)31 266 3263

Contact Melanie Stemmer for an entry form or download it from the website.

CONFERENCE ENDORSED BY

t: +27 (0)31 266 3263 e: conference@imesa.org.za marketing@imesa.org.za www.imesa.org.za

IMESA ORGANISER

THE INSTITUTE OF MUNICIPAL ENGINEERING OF SOUTHERN AFRICA (IMESA)

CEMENT & CONCRETE

New limestone quarry for AfriSam at Ulco As the impor tant mineral component of its cement, limestone will soon be mined from a new deposit by AfriSam’s Ulco cement plant in the Nor thern Cape. The relocated quarr y will be capable of providing security of supply for about 40 years and will need to deliver around 2 million tonnes of limestone to Ulco each year.

A

ccording to Gavin Venter, Manager Saldanha and Strategic Projects at AfriSam, the enabling infrastructure for this quarry has been significant. “After conducting a number of wide-spaced prospecting campaigns – as well as closespaced drilling across 100 hectares – we identified the best limestone reserves on our mining right on the opposite side of the R31 national road, which runs between the new site and the plant,” he explains.

“This means it is necessary to construct tunnels under the road to facilitate safe access between the new quarry site and the existing plant. Adding to the complexity is that the large Gamagara water pipeline runs parallel to the road.”

The R31 road between Kimberley and Postmasburg carries high volumes of large ore trucks and abnormal load mining

equipment. It will be diverted in early 2024 to accommodate this traffic for about six months while extensive excavation and civil engineering work is undertaken to construct the tunnel underpass system.

“In compliance with the road authority’s requirements, the tunnels will traverse the full 32 m width of the road reserve – to allow for future road widening, in addition to the pipeline servitude,” Venter continues.

The two tunnels themselves will be over 50 m in length and will be separated to enhance safety as there will be counterflow traffic to and from the plant. These 5 m high by 5 m wide tunnels will be excavated to 12 m below the R31 road level and constructed as large culverts with steel reinforced in-situ cast concrete.

The design work ensured a tunnel alignment to suit the future possibility of an in-pit crusher and conveyer belt. If such an option was

AfriSam’s Ulco cement factory is located in South Africa’s Northern Cape province and has a production capacity of 4 000 t of clinker per day

Hannes Meyer, AfriSam Cementitious Executive

Gavin Venter, AfriSam Manager Saldanha and Strategic Projects

financially justified in future, it would provide an alternative method to feed crushed material to the existing pre-blending stockpiles.

The civils works also has to accommodate the 700 mm diameter Gamagara pipeline, supplying the Northern Cape with water from the Vaal River. To avoid the risk of disrupting this water supply, a concrete bridge has been constructed parallel to the existing pipeline, inside which a new 100 m stretch of pipeline was laid.

“This provided the necessary support for the pipeline so that excavation and controlled blasting can be conducted underneath,” explains Venter. “As a fur ther precaution, there is also a 100 mm per second vibration limit applied to any blasting activity around the pipeline bridge.”

Work on the pipe bridge began in late 2022, with excavation work commencing in the third quarter of 2023, creating the initial slot on the south side of the R31. Once the road is diverted, the excavation of the tunnels can

IMIESA Jan/Feb 2024

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AECOM siphokuhle.dlamini@aecom.com AFI Consult banie@afri-infra.com ARRB Systems info@arrbsystemssa.com Asla Construction (Pty) Ltd johanv@asla.co.za BMK Group brian@bmkgroup.co.za Bosch Projects (Pty) Ltd mail@boschprojects.co.za BVI Consulting Engineers marketing@bviho.co.za CCG puhumudzo@ccgsytems.co.za / info@ccgsystems.co.za Corrosion Institute of Southern Africa secretary@corrosioninstitute.org.za Dlamindlovu Consulting Engineers & Project Managers info@dlami-ndlovu.co.za EFG Engineers eric@efgeng.co.za Elster Kent Metering Mark.Shamley@Honeywell.com EMS Solutions paul@emssolutions.co.za ENsync Engineers info@ensync.africa ERWAT mail@erwat.co.za Gabion Baskets mail@gabionbaskets.co.za GIBB marketing@gibb.co.za GIGSA secretary@gigsa.org GLS Consulting info@gls.co.za Gorman Rupp Cordeiro@gormanrupp.co.za Gudunkomo Investments & Consulting info@gudunkomo.co.za Hatch Africa (Pty) Ltd info@hatch.co.za HB Glass Filter Media info@hardybulkinglass.com Herrenknecht schiewe.helene@herrenknecht.de Huber Technology cs@hubersa.com info@edams.co.za Hydro-comp Enterprises Infrachamps Consulting info@infrachamps.co.za INFRATEC info@infratec.co.za Institute of Waste Management of Southern Africa iwmsa@iwmsa.co.za IQHINA Consulting Engineers & Project Managers info@iqhina.co.za iX engineers (Pty) Ltd hans.k@ixengineers.co.za Izinga Holdings info@izingalabezi.co.za JBFE Consulting (Pty) Ltd issie@jbfe.co.za JG Afrika DennyC@jgafrika.com KABE Consulting Engineers info@kabe.co.za Kago Consulting Engineers kagocon@kago.co.za Kantey & Templer (K&T) Consulting Engineers ccherry@ct.kanteys.co.za Kitso Botlhale Consulting Engineers info@kitsobce.co.za salesza@ksb.com KSB Pumps and Valves (Pty) Ltd KUREMA Engineering (Pty) Ltd info@kurema.co.za Lektratek Water general@lwt.co.za muzi@loshini.co.za Loshini Projects Makhaotse Narasimulu & Associates mmakhaotse@mna-sa.co.za Mariswe (Pty) Ltd neshniec@mariswe.com Martin & East gbyron@martin-east.co.za M & C Consulting Engineers (Pty) Ltd info@mcconsulting.co.za Mhiduve adminpotch@mhiduve.co.za MPAMOT (PTY) LTD mpumem@mpamot.com Mvubu Consulting & Project Managers miranda@mvubu.net Nyeleti Consulting naidoot@nyeleti.co.za Odour Engineering Systems mathewc@oes.co.za amarunga@prociv.co.za Prociv Consulting & Projects Management Rainbow Reservoirs quin@rainbowres.com maura@re-solve.co.za Re-Solve Consulting (Pty) Ltd Ribicon Consulting Group (Pty) Ltd info@ribicon.co.za francisg@rhdv.com Royal HaskoningDHV info@sabita.co.za SABITA mberry@safripol.com SAFRIPOL SAGI annette@sagi.co.za info@salga.org.za SALGA SAPPMA admin@sappma.co.za / willem@sappma.co.za SARF administrator@sarf.org.za.co.za SBS Water Systems marketing@sbstanks.co.za Silulumanzi Antoinette.Diphoko@silulumanzi.com admin@siroccon.co.za Siroccon International (Pty) Ltd SiVEST SA info@sivest.co.za Sizabantu Piping Systems (Pty) Ltd proudly@sizabantu.com Siza Water (RF) Pty Ltd PA@sizawater.com Sky High Consulting Engineers (Pty) Ltd info@shconsultong.co.za SKYV Consulting Engineers (Pty) Ltd kamesh@skyv.co.za Smartlock jp.alkema@smartlock.net capetown@smec.com SMEC Sabiha@savegroup.co.za SOUTH AFRICAN VALUE EDUCATION Southern African Society for Trenchless Technology director@sasst.org.za jomar@srk.co.za SRK Consulting Star Of Life Emergency Trading CC admin@staroflife.co.za Structa Group info@structatech.co.za TPA Consulting roger@tpa.co.za Ultra Control Valves peter@ultravalves.co.za V3 Consulting Engineers (Pty) Ltd info@v3consulting.co.za VIP Consulting Engineers esme@vipconsulting.co.za VNA info@vnac.co.za Water Institute of Southern Africa wisa@wisa.org.za Wam Technology CC support@wamsys.co.za Wilo South Africa marketingsa@wilo.co.za WRCON ben@wrcon.co.za Zutari Rashree.Maharaj@Zutari.com

CEMENT & CONCRETE

Existing Ulco operation with new mining area outlined in red

begin and is expected to be complete by end February 2024. This will be followed by the construction of the two tunnels.

The supply of readymix – which will include AfriSam cement – will come from Kimberley, about 80 km south. With ambient daytime temperatures that can rise to 40 degrees, this will require careful use of admixtures to achieve the required slump by the time readymix trucks arrive on site.

Mining topography “Mining is expected to begin in the second half of 2024, with an unusual topography in which the quarr y will be mined into an escarpment,” says Hannes Meyer, Cementitious Executive at AfriSam. “Transportation of mined material is therefore mainly downhill. With the gradient of the haul road slopes limited to 5 degrees, AfriSam’s truck-trailer combinations have been designed to be much more energy efficient than conventional off-road dump trucks.”

AfriSam commissioned various specialist studies as par t of its environmental impact assessment to investigate the new quarry’s potential effects on wetlands, terrestrial life, hydrology, heritage and traffic. Authorisation was granted to mine in the vicinity of water features on the proposed mining area, with a seasonal drainage line that had to be diverted to avoid the exit slot of the new haul road.

Ulco project area showing the development of the R31 bypass and drainage line diversion above it

IMIESA Jan/Feb 2024

51

TRANSPORTATION

By the end of 2025, a growing number of electric commuter buses could be on the roads of Tshwane and eThekwini as par t of a pilot project funded by the Global Environmental Facility (GEF) and managed by the Development Bank of Southern Africa (DBSA) and the South African National Energy Development Across the world cities Institute (SANEDI). are shifting to electric buses as a cleaner and smarter solution

PILOT SCALE ELECTRIC BUS DRIVE FOR TSHWANE AND ETHEKWINI

S

ANEDI, which was appointed by the DBSA as the project’s implementing agent, has announced that 39 buses and the associated charging infrastructure will be purchased and rolled out with the US$4,7 m in funding secured.

The project will be implemented over a period of five years, with half the buses being commissioned in the first two years. The City of Tshwane will be allocated 20 buses and eThekwini 19.

“During this time, we will demonstrate the technical, operational, legal, economic and other feasibility factors, and bed down the specifications of the ecosystem needed

to support electric buses in South Africa,” explains Tebogo Snyer, project manager for SANEDI’s cleaner mobility programme.

Snyer says that although the intention is to procure locally as much as possible, the buses will have to be imported as no local manufacturing capacity exists as present.

“We do manufacture some electric charging equipment in South Africa, but what we need to procure will depend on the buses we decide to test.”

Electric vehicles are one component of the worldwide drive to cleaner mobility, which includes natural gas. Currently, electric vehicle technology is the furthest developed and continues to advance due to the interest

in it across the globe and the significant resources that China, in particular, is investing in growing the sector.

Cost of ownership Snyer expects the technology to revolutionise the transport sector in the next three to five years on the back of improved and cheaper batteries, which will also lower the cost of ownership significantly. Currently, total of cost of ownership is 5% to 10% less than internal combustion buses, but the much higher upfront capital outlay limits adoption.

The main selling points, however, are the absence of emissions and giving South Africa an alternative to imported diesel.

INDEX TO ADVERTISERS AfriSam AKS Lining Systems

44 20, OBC

APE Pumps | Mather+Platt

11

Astec

41

Bosun Concrete Products

31

52 IMIESA Jan/Feb 2024

BVi Consulting Engineers Envitech Gabion Baskets IMESA KSB Group Lintec & Linnhoff

8 21 17 20, 48, 50 4 2

Rand Water

13, 32

SIKA

IBC

Sizabantu Piping Systems

IFC

Sudpave | Bergesen Agencies Vega

27 OFC, 6

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