IMIESA October 2023

www.imesa.org.za

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

INFRASTRUC TURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY

INDUSTRY INSIGHT Sandile Mkhize Chief Executive Magalies Water

Magalies Water extends its footprint to serve all of North West

AfriSam Creating Concrete Possibilities

TRANSPORTATION ENGINEERING Skid resistance vs surface texture

TRENCHLESS TECHNOLOGY Lining options for pipeline rehabilitation

COMMUNITY-BASED PROJECTS Celebrating Emansomini’s new pedestrian bridge

I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 7 N o . 0 1 • J a n u a r y 2 0 2 2 • R 5 5 . 0 0 ( i n c l . VAT ) I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 8 N o . 0 9 • O c t o b e r 2 0 2 3 • R 5 5 . 0 0 ( i n c l . VAT )

UMNGENI-UTHUKELA

WATER . AMANZI

UMNGENI-UTHUKELA WATER GOES CIRCULAR uMngeni-uThukela Water (UUW) is a bulk water and sanitation service provider that strongly emphasizes sustainable resource management and operational efficiency.

he entity as a whole is devoted to the transformative process supported by the circular economy and aims to reduce the adverse impacts brought on by the legacy of the linear economy. So much so that their Environmental Sustainability Strategy includes the commitment to moving toward a circular economy as one of its key objectives.

This has led to the development of a more comprehensive circular economy plan that strives to assure flow through the water economy by utilizing products and materials for as long as possible while maintaining their maximum value in order to minimize waste and enhance resource efficiency. This economy is within and externally of Umngeni-Uthukela Water (UUW).

The circular economy approach of UUW presents circular solutions that aid in improved resource management thus ultimately encouraging better water management within the water sector. These are solutions that lessen the need to abstract

more natural resources by strengthening water management, maximizing the value of current resources, and preventing water pollution.

For instance, Darvil Wastewater Treatment Works, the largest wastewater treatment facility at UUW, is progressively shifting from conventional wastewater treatment practices and towards a facility which promotes circularity and closed-loop activities by bridging the gap between waste and resources. UUW realises the potential for resource recovery and aims to unlock the latent value of wastewater streams.

Wastewater has a wealth of potential as a resource that may be unlocked by combining a variety of technologies and procedures. Resource efficiency can be greatly enhanced by the extraction of valuable materials from wastewater streams, such as nutrients and energy. UUW intends to concentrate on building viable and scalable solutions. UUW realises that resource recovery not only reduces waste but also creates new revenue streams and contributes to a circular economy.

FOR MORE INFORMATION CONTACT uMngeni-uThukela Water 310 Burger Street Pietermaritzburg 3201 Tel: 033 – 3411 111

Joining forces to improve Water and Sanitation service delivery for all communities in KwaZulu-Natal.

© Umngeni-uThukela Water 2023

T

INSIDE

VOLUME 48 NO. 09 OCTOBER 2023

48 Regulars www.imesa.org.za www.imesa.org.za

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

INFRASTRUC TURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY

INDUSTRY INSIGHT Sandile Mkhize

Chief Executive Magalies Water

Magalies Water extends its footprint to serve all of North West

AfriSam Creating Concrete

Possibilities

TRANSPORTATION ENGINEERING Skid resistance vs surface texture

Editor’s comment President’s comment Index to advertisers

3 5 56

Cover Story The ways that AfriSam creates concrete possibilities

6

Health & Safety The role of the construction manager in construction health and safety

10

TRENCHLESS TECHNOLOGY Lining options for pipeline rehabilitation

COMMUNITY-BASED PROJECTS Celebrating Emansomini’s new pedestrian bridge

I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 7 N o . 0 1 • J a n u a r y 2 0 2 2 • R 5 5 . 0 0 ( i n c l . VAT ) I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 8 N o . 0 9 • O c t o b e r 2 0 2 3 • R 5 5 . 0 0 ( i n c l . VAT )

ON THE COVER

12

Trenchless Technology Considerations when designing linings for rehabilitating existing pipelines

An industry icon, AfriSam has been part of the construction landscape since 1934 through various evolutionary stages, with the current brand name introduced to the market in 2008.

Those close to nine decades of growth have been based on concerted research and development, and an ability to respond to cyclical demand, says Richard Tomes, Sales and Marketing Executive, AfriSam. P6

28

ENVIRONMENTAL ENGINEERING

41

Transportation Engineering Skid resistance vs surface texture and their safety implications XXVII PIARC conference puts the spotlight on safety

44 47

20

Vehicles & Equipment Gqeberha plant hire specialist adds six new JCB backhoes

22

26

Environmental Engineering Minimise harm to the environment with bioremediation

36

The forming of Emansomini’s new pedestrian bridge across the Mbokodweni River 48

Information & Communications Technology Responsible and ethical AI process automation has its part to play

34

16

Consulting Engineers Value engineered solutions for municipal service delivery

33

Roads & Bridges

Geomatics Land surveyors – the pioneers of precision

32

Pipe Systems Thermoplastic pipe material classification and pipe stiffness

Industry Insight Magalies Water extends its footprint to serve all of North West

Maintaining kikuyu the Water Wise way Versatility in dewatering for the most demanding jobs Double Win – SBS Tanks brings water security to two communities at once New Shongweni reservoir creates additional capacity and community opportunity

28

51

Cement & Concrete Concrete mix designs now more important than ever Column refurbishment for Gqeberha warehouse Seamless production supports aggregate targets on N3 revamp Nominations now open for CCSA’s 2024 Fulton Awards

52 53 55 56

Water & Wastewater Unearth the hidden leaks in your landscape Navigating the complexity of water use licence applications

36

WATER & WASTEWATER

29 30

INDUSTRY INSIGHT Headquartered in Rustenburg, Magalies Water is now the North West Province’s sole water board following the recent integration of the previous operations managed by the now disbanded Sedibeng Water entity.

IMIESA speaks to Chief Executive, Sandile Mkhize, about the entity’s strategy going forward.

P12

87

TH IMESA

CONFERENCE

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)

EDITOR’S COMMENT EDITOR Alastair Currie Email: alastair@infraprojects.co.za DESIGNER Beren Bauermeister CONTRIBUTORS Hennie Colyn, Yaseen Francis, Alaster Goyns, Chris Kirchhoff, Tony Lewis, Sibusiso Mjwara, Kaslyn Naidoo, Simamnkele Ngxesha, Bryan Perrie, Mike Smart DISTRIBUTION MANAGER Nomsa Masina DISTRIBUTION COORDINATOR Asha Pursotham SUBSCRIPTIONS Email: IMIESAdistribution@infraprojects.co.za ___________________________________________________ ADVERTISING SALES KEY ACCOUNT MANAGER Joanne Lawrie Tel: +27 (0)11 234 0825 / +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: R600.00 (INCL VAT) ISSN 0257 1978 IMIESA, Inst.MUNIC. ENG. S. AFR. © Copyright 2023. 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 Olivier 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.

Diesel hikes, loadshedding and taxation

W

e continue to experience an energy rollercoaster of note but should be able to cap loadshedding at Stage 4 for the summer months, according to Eskom. That is an indication of just how severe the maintenance backlog is, with the country’s National Energy Crisis Committee making a concerted effort to end recurring power outages in the shortest possible timeframe in achieving sustained energy security.

Working with industry experts, technical support teams have been deployed to five key power stations – namely Kendal, Kriel, Majuba, Matla and Tutuka – as well as to bring all units at Kusile back online as soon as possible.

In the meantime, the uptake for rooftop solar PV is accelerating and – while keeping the lights burning for households and business – is helping to take pressure off Eskom as it works to find quickwin solutions.

It’s clear that falling back on diesel gensets as a last resort is far from financially sustainable as the inland price per litre climbed past R25,00 in October. These constant price hikes during 2023 are obviously bad news for the economy and employment security as businesses struggle to sustain positive trading margins.

Solar incentives That should provide the South African Revenue Service with more than enough motivation to extend the rooftop solar PV taxation rebate periods for at least the next two tax years. The limit for households for the 2023/24 period could also be increased from the current R15 000 threshold to further drive widespread adoption.

The money ploughed back into the economy would also have a positive spin-off for SMME installers and PV manufacturers.

Tax revenues We all know that taxation funds government, but it also enables a vibrant society and economy, so taking pressure off taxpayers wherever practical is important.

Equally so is the way collected taxes (like fuel levies, and the Carbon Tax) are channelled back – particularly in support of vital areas like education, healthcare and infrastructure development.

Times are tough globally, but for developing countries like South Africa – with its large informal economy

Growth areas attract migrants From a trading perspective, Gauteng remains the business hub – generating around R33 out of every R100 produced by the South African economy in 2022.

For this reason, the province is a major destination for job seekers, with Statistics SA stating that individual migrant inflows could be in the region of 1,4 million over the 2021-2026 period. The second largest migration zone is the Western Cape, at a projected 0,46 million.

Census 2022 and spatial planning That has major implications for infrastructure service planning and provision, which will be shaped in part by the findings of the Census 2022 report – the fourth in the series first initiated in 1996. Statistics SA says that phase one of the report’s release will cover reports and indicators at national, provincial, district and local municipality level. Data will then be made available in the second phase.

Either way, South Africa’s population keeps growing, and that will have a major influence on energy demand, as well as its interrelated requirements to power critical infrastructure, like water and wastewater.

The pressure keeps building. Therefore, for an effective economic recovery, government will now need to work even hard to reduce public debt and ensure SOE entities that absorb a large portion of the tax gains can deliver as positive catalysts for change in all areas. They need to be financially self-sufficient and profitable.

Partnering with investors and empowering the construction sector is a core part of the recovery process in stimulating real growth that reduces the tax burden on consumers and promotes enterprise development.

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

INFRASTRUC TURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY

INDUSTRY INSIGHT Sandile Mkhize

Chief Executive Magalies Water

Magalies Water extends its footprint to serve all of North West

AfriSam

Creating Concrete Possibilities

TRENCHLESS TECHNOLOGY Lining options for pipeline rehabilitation

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.

TRANSPORTATION ENGINEERING Skid resistance vs surface texture

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

and high unemployment – the knock-on effect is a constrained and potentially shrinking tax base. For the 2021/22 period, the three highest contributors were personal income tax at 35,5%, followed by VAT at 25% and then company income tax at 20,7%. In terms of the latter, mining and manufacturing were major contributors but have contributed less to the fiscus in recent years.

COMMUNITY-BASED PROJECTS Celebrating Emansomini’s new pedestrian bridge

I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 7 N o . 0 1 • J a n u a r y 2 0 2 2 • R 5 5 . 0 0 ( i n c l . VAT ) I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 8 N o . 0 9 • O c t o b e r 2 0 2 3 • R 5 5 . 0 0 ( i n c l . VAT )

IMIESA October 2023

3

SMOOTH SAILING WITH SEAPRO SA:

Unleash the Potential of the CLA-VAL Control Valve Are you ready to navigate the waters of fluid management with confidence and ease? Look no further than the CLA-VAL Control Valve, the flagship product of the renowned CLA-VAL brand. Its exceptional features, advantages and benefits will revolutionise the way you approach fluid control.

Features: The CLA-VAL Control Valve boasts an impressive array of features that set it apart from the competition. From its precisionengineered pressure control capabilities to its versatile flow control and level control functionalities, this valve is designed to deliver unparalleled performance. With its specialised design for pump control, it ensures smooth and efficient operations – even in the most demanding applications.

Advantages: What sets CLA-VAL Control Valve apart is not just its technical powers, but also the expertise of the Seapro SA technical team. With their deep understanding of fluid dynamics and years of experience, they provide invaluable support and guidance throughout your journey. Additionally, the CLA-VAL brand offers an astounding 4 500 different configurations, giving you the freedom to customise the valve to perfectly match your unique requirements.

Benefits: By choosing the CLA-VAL Control Valve, you unlock a world of benefits. Experience smart water management at its finest as you achieve precise control over flow rates, maintain optimal pressure levels and maximise the efficiency of your fluid systems. Not only does it deliver exceptional performance, but it also represents excellent value for your money – making it a sound investment for your operations. And as a bonus, Seapro SA provides free Link2Valve software, empowering you with advanced tools for flow, pressure, and asset management.

Embark on a journey of smooth sailing with CLA-VAL Control Valves by Seapro SA. With its cutting-edge features, technical expertise, and unmatched value, it’s time to unleash the full potential of your fluid management systems. Get ready to navigate with confidence and efficiency like never before.

On/Off Electrical Remote Control Valve

90-01 Pressure Reducing Control Valve

50-01 Pressure Relief/Sustaining Control Valve

D12 99-01 Pressure Modulation Control Valve

+27 (0)11 397 1126 + 11 (0)10 109 2703 info@seaprosa.co.za www.seaprosa.co.za

PRESIDENT’S COMMENT

IMESA

EFFICIENT TRANSPORTATION DEFINES ECONOMIES AND CONNECTS COMMUNITIES Irrespective of whether you’re based in the developed or developing world, transportation engineering is the deciding factor in macroeconomic trade – shipping goods to markets regionally and internationally by air, rail, road, rivers, and sea routes.

T

his is a complex engineering endeavour that requires detailed planning within countries and across nations in the interests of commerce, with the priority of always enabling all levels of enterprise – micro and macro – to succeed.

Within our broader local context, the African Continental Free Trade Area aims to link some 54 countries in a proactive and fair commercial environment. That in turn is being bolstered by domestic and direct foreign investment. But investment within the SADC region is a more immediate and obvious priority when it comes to our regional cross-border trade activities.

From a transportation perspective, that includes alleviating port congestion, as well as truck traffic build-ups at borders, which continue to increase in concentration within SADC due to a progressive decline in rail capability.

The latter factor is not a positive outcome, because rail transportation is one of the most effective and cost-efficient ways to deliver goods and services – and commuters – over long distances or within urban Smart City contexts.

Phase I of the approximately 80 km Gautrain Rapid Rail Integration Network interconnecting the Johannesburg and Pretoria CBDs, and

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

Sandton with OR Tambo International Airport is a commendable achievement. Certain stages were completed ahead of South Africa’s FIFA 2010 Soccer World Cup hosting, and the balance around 2012. Now Phase II feasibility studies are in progress, which in the future envisaged construction stages will definitely add value.

However, it remains a relatively premium priced service for lower earning consumers who still need to find a cheaper way to get to and from work, school and enterprise activities in the absence of an effective state passenger rail service.

Taxis and BRTs Enter the minibus taxi industry – South Africa’s and Africa’s predominant choice of commuter transport based on convenience and cost.

While its regulation remains challenging – recent protest action within the City of Cape Town being a case in point – there’s no doubt that this industry remains the mainstay of the daily commute for most South Africans.

Within the mix is the evolving Bus Rapid Transit (BRT) network across South Africa’s metropolitan cities. The key advantage of BRTs is their dedicated bus lanes, which enable free movement, along with the modern-day convenience of e-services for payment and scheduling. While we often think of countries like Brazil as the birthplace of BRT, the first known system globally was actually introduced in 1971 in England. Now some 166 cities worldwide have BRT networks in place, catering for some 32,2 million daily commuters.

National, municipal and gravel routes However, in South Africa public transport still remains largely informal (i.e., taxis) for most. For the balance of the population, private vehicle use continues to

dominate, as do trucks for industry as the main cargo and logistics tool – particularly on national city-to-city routes managed by SANRAL. To date, SANRAL has done an exceptional job in maintaining and expanding its approximately 22 253 km network to meet rising commercial and private vehicle demand. Examples include major investments on the N3 between Pietermaritzburg and Durban, and Eastern Cape upgrades that include the N2 Wild Coast route.

Key components of the latter include the N2 between East London and Mthatha and the R61 between Mthatha and Ndwalane, plus the two mega bridges crossing the Msikaba and Mtentu Rivers.

These are landmark infrastructure projects that will make a major difference. However, of equal importance is the maintenance and upgrading of the municipal road network. And while we try to get on top of our “pothole pandemic” we mustn’t forget the importance of the gravel road network – an essential conduit for rural communities.

e-mobility In the meantime, the South Africa government is forging ahead with its National Transport Master Plan. To work effectively, it will need to synch with future town and city spatial planning, and factor in smart e-mobility. That includes intelligent traffic management systems and a greater focus on electric vehicles – hopefully driven by a vibrant local manufacturing segment. Transportation routes will also need to keep pace with the rollout of network charging stations – as we’re seeing in the UK and Europe – backed by proactive public private partnership engagement.

It’s all about establishing the business case.

A high-speed rail line between Durban and Johannesburg would be great, but our immediate priority is to make sure our existing transportation assets are optimised and work.

IMIESA October 2023

5

COVER STORY

The ways that AfriSam creates

concrete possibilities

An industry icon, AfriSam has been part of the construction landscape since 1934 through various evolutionary stages, with the current brand name introduced to the market in 2008. Those close to nine decades of growth have been based on concerted research and development, and an ability to respond to cyclical demand, says Richard Tomes, Sales and Marketing Executive, AfriSam.

A

s we know, South Africa’s economic fortunes are constantly being influenced by global outcomes, especially the constant escalation in diesel fuel prices. That impacts all levels of business and society and influences the current inflationary environment from a consumer and producer perspective,” says Tomes.

6 IMIESA October 2023

“However, we cannot control the financial or oil markets, so we need to focus on what we can fix, like putting an end to loadshedding, promoting a green economy, and ensuring that infrastructure spend

Richard Tomes, AfriSam Sales & Marketing Executive

remains a top priority for government – both in terms of new build and maintenance of existing assets. Our commitment in turn as AfriSam is to keep investing in the future of South Africa through our diverse

By actively mapping quarry rock type and quality, AfriSam’s technical experts ensure that blasted material is expertly paired with the design engineers’ requirements in terms of specific grading, shape and wearing properties

COVER STORY

Since 1990, AfriSam has been able to reduce the volume of carbon dioxide emissions per tonne of cementitious material by 33%

range of cement, aggregate and readymix solutions,” says Tomes.

Economic analysis For a number of years now – and as a service to industry – AfriSam has hosted its annual Budget Breakdown Breakfast in February following the annual National Budget Speech by South Africa’s Minister of Finance. Since inception, AfriSam’s Budget Breakdown presentation has been led by Dr Azar Jammine, director and chief economist at Econometrix, a recognised expert whose insights are crucial for medium to long-term forecasting.

“Our most recent engagement with Dr Jammine in September 2023 shows that inflationary pressures, and the potential for further interest rate hikes remains on the cards. In response, buying patterns have been influenced, and we need to ensure

that our solutions tie in with customer requirements, and pricing,” Tomes continues.

“During the initial lockdown period, for example, there was a huge surge in cement sales as the ‘work from home/hybrid’ model created an unprecedented demand for residential building extensions going into 2021. However, based on our analysis, we see an overall contraction in industry cement demand of around 18 to 20% in 2023 compared to 2022.”

“The traditional split between bulk and bag sales has also shifted. Instead of being 50/50, we’re now seeing around 2/3rds of

our cement sales being channelled through retailers, and the remaining third sold in bulk form direct to contractors and concrete product manufacturers. It’s indicative of the slowdown in public sector spend on infrastructure, and mixed fortunes in the property sector. Either way, in tougher times we need to be even more efficient and effective as a producer to keep our customers competitive.”

Project pipeline The mega projects, like Phase II of the Lesotho Highlands Water Project, hold great

IMIESA October 2023

7

COVER STORY

AfriSam is currently supplying the Refinery Interchange on the N7 highway north of Cape Town

promise for AfriSam. For Phase I, which was completed in 2003 and inaugurated in 2004, Alpha Limited – AfriSam’s trading name at the time – supplied a major portion of the cement required – shipped from its Ulco plant in the Northern Cape via a direct rail line to Lesotho.

For Phase II, AfriSam envisages that 100 000 tonnes of cement a year will be required as the project ramps up with the construction of the Polihali Dam and transfer tunnel, the three main bridges to be built ahead of its impoundment, plus associated works.

In terms of other current major projects in South Africa, AfriSam is supplying road infrastructure developments that include the N3 Pietermaritzburg to Durban upgrade, the N7 upgrade outside Cape Town, as well as the R63 route from Fort Beaufort to Alice in the Eastern Cape.

Orders include the supply of aggregates and AfriSam Roadstab Cement for layer works and sub-base stabilisation, respectively. Allied to this is the supply of readymix concrete for ancillary works like bridges and culverts.

Within Gauteng – South Africa’s economic heartland – supply contracts for the property development market include the 5 Parks Boulevard Project in Oxford Parks, the

The SANAS recertification of AfriSam’s laboratory assures customers and the broader industry of AfriSam’s ongoing commitment to quality standards that match the world’s best

8 IMIESA October 2023

Trevenna Super Basement Project and the new Government Employee Pension Fund building in Sunnyside, Pretoria.

SA cement capacity At present, the South Africa cement industry has a total capacity of between 18 and 20 million tonnes per annum (mtpa). However, current demand is sitting at between 12 and 13 mtpa. Despite this, South Africa remains an export destination for countries that include Vietnam, with annual cement import volumes hovering at around 1 mtpa.

CCSA alliance and industry compliance Through industry body, Cement & Concrete SA – which AfriSam supports as one of the Partner Members – engagement is ongoing to secure some form of safeguard protection.

As part of the World Trade Organisation, South Africa acknowledges the importance of free and fair competition. However, in South Africa, there are additional commitments like the five-year rolling Social Labour Plan (SLP)

component of the Mining Charter that local limestone and aggregate operations need to comply with.

Added to this is the BBBEE requirement, and South Africa’s Carbon tax. As Tomes points out, these are not requirements that cement importers need to comply with, so arguably that is not a fair trade arrangement.

Plus, imports need to adhere to all local and international standards – and this may not always be the case, with downstream health and safety concerns for structures built using these materials.

By law, South African cement must be specified for local government funded public works. The same does not apply for private developments.

“The CCSA is the key industry body in championing excellence and technical education in our industry, and in ensuring we have a collective voice in liaising with government. Membership includes individuals and companies, and we strongly encourage all interested parties to join,” says Tomes.

Community Development Programme From a Mining Charter perspective, AfriSam has a comprehensive Community Development Programme in place which demonstrates its commitment to corporate stewardship. These include community recreational areas, where previously derelict and dangerous areas have been turned into safe spaces to exercise, play and interact; the provision of a state-of-the-art science laboratory, as well as a computer lab for schools in the Northern Cape; the construction of an Early Childhood Centre

COVER COVER STORY STORY

AfriSam’s e-experience platform, ClickToGo, is a first of its kind in the industry

in Cape Town, and a Health Clinic near its Umlaas Road Quarry in KwaZulu-Natal; plus 18 houses built for disabled and childheaded households in Nigel, Gauteng.

Catering for the full industry spectrum “Our customers represent the full spectrum of the market, from ‘ bakkie builders’ to JSE-listed construction giants, architects, consulting engineers, and municipal engineers within SOEs and municipalities.

For this reason, we tailor our product, technical advice and training solutions to match, including how products are sold and supplied,” says Tomes.

AfriSam’s Centre of Product Excellence (CPE) is the business hub for technical advice, customer training and expert consulting services in terms of fit-for-purpose product and/or mix design selection for specific projects. The AfriSam Roodepoort laboratory recently passed stringent SANAS recertification requirements aligned to international ISO/IEC 17025 management system standards. This makes it one of South Africa’s most specialised facilities for testing cement and concrete materials, as well as the proving of theoretical mix designs.

“For designers and contractors, it’s about finding the right balance in terms of performance while factoring in sustainability objectives and costs,” says Tomes. “Concrete roads, for example, have proven themselves time and again as highly durable structures with lower lifecycle costs compared to flexible pavements. Concrete roads are also greener in terms of reduced emissions.”

Within the township and emerging contractor market, language and literacy

AfriSam continues to invest in the communities surrounding its operations, such as the state-of-the-art science laboratory donated to the Dikgatlong School in the Northern Cape

levels are taken into account, including packaging with easy-to-follow instructions.

Another innovation is AfriSam’s launch of the Plan (a) campaign. This enables customers to build and progressively extend their own home overtime from an architect approved plan.

“There’s clearly a need for a highly credible platform where key segments of the housing market can be empowered with professional insights and tools,” says Tomes. In recognition, Plan (a) was shortlisted for a Sustainable Development Goals (SDG) Lion award for its positive contribution to the world.

ClickToGo Another innovation that is adding major value is AfriSam’s ClickToGo service – a user-friendly e-commerce platform for 30-day and cash account customers, the majority of whom are contractors placing bulk orders for cement, aggregates and/or readymix.

Customers can directly order from quotes, review their order history, access essential account documents and credit information, and track deliveries.

ClickToGo also enables cash account customers to apply for a credit facility directly through the platform. Additionally, 30-day account customers can now request credit limit increases online. To date more than 70% of AfriSam’s account customers are registered for the service in South Africa, with the possibility of extending the service to eSwatini and Lesotho where AfriSam has existing depots.

Eco products Going green is an SDG imperative and in 2009 AfriSam was the first in industry to introduce a carbon dioxide rating system. In this respect, AfriSam has been able to reduce the volume of carbon dioxide emissions per tonne of cementitious material by around 33%. Another example is AfriSam’s readymix operations, where water is extensively recycled.

AfriSam is also a leading innovator in the field of cementitious extenders and the only producer of slagment – a waste product from the steel industry.

A consistently strong outlook “The challenges for South Africa are there for all to see, but the momentum remains positive as the country rebounds – with the rest of the world – from a very tough Covid period. G7 and BRICS investors remain committed to the country’s sustained growth, and the anticipated outcome of the South African National Elections being concluded in a way that will provide the market with greater future policy certainty,” adds Tomes.

“Future growth will hinge increasingly on private sector infrastructure investment and in South Africa AfriSam is an enduring part of the current and future economic equation,” Tomes concludes.

www.afrisam.com

IMIESA October 2023

9

HEALTH & SAFET Y

THE ROLE OF THE CONSTRUCTION MANAGER IN CONSTRUCTION HEALTH AND SAFETY Construction management is an elaborate job that requires technical and interpersonal skills in order to achieve success through planning, administration, implementation, and management of resources on a construction site (Howes, 2009 and RSA, 2014). These skills must be best utilised during the construction process when multiple stakeholders are engaged to ensure that the objectives are achieved. By Yaseen Francis and Simamnkele Ngxesha

T

he construction manager plays a pivotal role in ensuring all objectives are met and success is achieved. However, in today’s changing world in which the construction industry is located, there can be conflicting objectives.

Ensuring decent working conditions through well-documented and effective health and safety (H&S) management is just one of the many objectives of a construction project.

Furthermore, construction managers are legally mandated by legislation to ensure H&S is effectively planned, administered, implemented, and managed on construction projects. This article highlights four key factors that construction managers can influence as central role players on construction projects.

Site management and H&S leadership The traditional approaches to management have given way to leadership skills. Construction managers at all levels need to develop interpersonal skill, intelligent and transformational leadership qualities to meet up with contemporary management challenges. The quality of leadership at the top level determines the H&S behaviours of workers on site. It is the responsibility of the top leaders to

10 IMIESA October 2023

LEFT: Yaseen Francis, executive director, ACHASM and principal consultant: SHERQ, NCC Environmental Services BELOW: Simamnkele Ngxesha, safety specialist, TB HIV Care

develop organisation H&S policies, allocate resources for H&S, approve H&S training of workers, and assign responsibility to managers and supervisors. (Okorie, et al, 2014).

Research undertaken by Smallwood and Haupt (2005) illustrate that all members in managerial positions and influence within a construction company are responsible for achieving continuous improvement in construction H&S performance. This comes as no surprise, as it has been effectively demonstrated that a strong H&S performance and H&S culture within an organisation is reliant on management commitment – even in those outside of the construction industry.

This commitment calls for strong leadership qualities from construction managers and entails inclusion, involvement, investment and participation.

Construction managers must be mindful of the H&S of their employees when drafting H&S policies, H&S plans and conducting risk management.

Construction managers are responsible for achieving and maintaining good H&S standards on site and ensuring employee wellbeing. Due to the nature of construction work, the workforce often works in remote or isolated locations and spend a considerable amount of time together.

Research by Flin and Yule (2003) indicates that construction managers and supervisors have contributed to changing the unsafe behaviours and unsafe acts of workers, such as enforcing the use of personal protective equipment (PPE) on site.

HEALTH & SAFETY

H&S in procurement and the construction programme Procurement in construction plays a critical role in shaping H&S outcomes on construction projects. The procurement process encompasses the selection of suppliers, subcontractors, and the methods by which construction projects are executed.

The construction manager and the H&S manager must interoperate specific requirements outlined in the client’s sitespecific H&S specification at the tender stage to ensure adequate H&S provision in the BOQ and include client specific H&S requirements in subcontractor tender documentation. This process may ultimately form part of the procurement strategy followed; however, it is essential that the construction manager is actively involved and fully comprehends the importance of H&S. By choosing subcontractors with a strong track record of prioritising H&S, construction managers can affect the H&S outcomes of a project. It is essential to verify the competencies and resources of subcontractors through a carefully executed and rigorous process.

Procurement processes that evaluate a contractor's safety performance and culture can lead to the selection of suppliers and sub-contractors that are committed to safe practices. This can be achieved by analysing the complexity associated with the work in conjunction with the safety metrics of the suppliers and sub-contractors.

The construction manager can also ensure that contractual obligations and the BOQ include H&S or require suppliers and subcontractors to demonstrate commitment to H&S. This can be achieved by requiring subcontractors to provide training for all staff involved in projects.

The construction manager can influence H&S through efficient programming in conjunction with the H&S officer by actively identifying key high-risk activities depicted on the construction programme that may require stringent H&S intervention and documentation, ensuring legislative requirements are met.

The construction programme can highlight key hold points that may require H&S input, such as specific documentation in the form of detailed method statements and risk assessments necessary for extensive demolition activities, specialist reports such as the asbestos inventory and risk assessment, the geotechnical report outlining pertinent protective methods, shoring, bracing and dewatering requirements or specialist competencies, i.e., temporary work designer. Depicting high-risk activities in the construction programme with specific notes will

enable the H&S officer to proactively manage safety and avoid typical delays relative to H&S requirements, i.e., method statement approvals.

Furthermore, the construction manager can further plan and sequence high-risk activities during specific periods to reduce or minimise interface or constraints with these activities in instances with a high public interface. For example, asbestos removal can be programmed to occur when there is limited construction activity, or roof work can be scheduled in less windy months.

H&S competency The construction manager is also responsible for ensuring that all staff under his/her supervision are competent in undertaking work safely and responsibly. However, first and foremost, it is important to note that the construction manager her/himself demonstrates competency is H&S. This could be through how the mechanism of competency is defined by the Construction Regulations of 2014, which states that he/she “has in respect of the work or task to be performed the required knowledge, training, and experience and where applicable the qualifications”.

Experience, knowledge, and training in the scope of works fulfils this definition, but it is advisable that further short courses in H&S are undertaken by the construction manager.

Experience may extend beyond the nature of construction management projects; however, it may include experience required on projects of a similar nature. For example, a competent construction manager who has worked primarily on civil projects must determine if they are qualified to manage and execute building projects. The scope and authority are limited and should be considered when accepting or assigning tasks.

According to the Construction Regulations of 2014, the construction manager must appoint in writing a construction supervisor who will supervise the construction activities to be undertaken on site. It is particularly important that the construction manager ensures that the

appointee has a demonstrated history of H&S implementation and is cognisant of the H&S challenges present.

Finally, the construction manager must ensure that the construction H&S officer on her/ his project is competent, is registered and in good standing with the South African Council for the Construction and Project Management Professions. Furthermore, the construction manager must be cognisant of the role of continuous professional development (CPD).

This will assist her/him, and the appointed construction H&S officer to continuously improve their understanding and their undertaking of construction projects.

Conclusion The construction manager must be well versed in the Construction Regulations 2014, the legal liabilities associated with the role in discharging duties regarding the regulation 8.1 appointment and develop an in-depth understanding of the regulation to ensure proper implementation of construction projects.

REFERENCES Flin, R. & Yule, S., 2003. Leading for Safety; Industrial Experience. Quality and Safety Health Care, 3(20, 45-51) Howes, C.J., 2010. Construction management versus construction project management.

Okorie, V., Smallwood, J., Van Wyk, J. and Emuze, F., 2014. A qualitative review of the health and safety leadership roles of managers in South African construction. Journal of construction project management and innovation, 4(2), pp.950-965.

Republic of South Africa., 2014.

Government Gazette No. 37305, Construction Regulations Pretoria Smallwood, J. and Haupt, T., 2005.

The need for construction health and safety (H&S) and the Construction Regulations: engineers' perceptions.

Journal of the South African Institution of Civil Engineering 47(2), pp.2-8.

IMIESA October 2023

11

INDUSTRY INSIGHT

MAGALIES WATER

EXTENDS ITS FOOTPRINT TO SERVE ALL OF NORTH WEST Headquartered in Rustenburg, Magalies Water is now the North West Province’s sole water board following the recent integration of the previous operations managed by the now disbanded Sedibeng Water entity. IMIESA speaks to Chief Executive, Sandile Mkhize, about the entity’s strategy going forward.

I

n addition to being a major agricultural region, North West is a vibrant mining hub for one of the world’s richest platinum group metals deposits, alongside diamond, granite, and limestone operations (the essential ingredient for cement production) – and all central to driving South Africa’s domestic and export economy.

These are all highly water-intensive industries, requiring sustained supply. Alongside this is an equally important community priority, especially given that the province has an approximately 80% rural population, not all of whom are currently connected to serviced potable water and waterborne sanitation.

1969, with raw water now sourced from four major dams owned by the Department of Water and Sanitation (DWS). They comprise Bospoort (surface area: 378,8 ha; abstraction source: Hex River), Roodekopjes (surface area: 1 571 ha; abstraction source: Crocodile River), Vaalkop (surface area 1 110.5 ha; abstraction source: Elands River and Hex River) and Roodeplaat (surface area: 403 ha; abstraction source: Pienaars River).

All these dams are situated in the North West Province, with the exception of the latter, which is located in Gauteng. Roodeplaat is presently dedicated to supplying the City of Tshwane.

Extended mandate Historical context From a historical perspective, the current trading operation was originally founded in

Following an agreement with Rand Water in 1999, Magalies Water expanded the Vaalkop Water Treatment Works to meet current and future demand within the Rustenburg region.

Then in 2003, the Magalies Water board took a strategic decision to explore retail water operations and maintenance (O&M) as part of its secondary obligations. This followed the promulgation of the Municipal Structures Act and Municipal Systems Act. Magalies Water Board’s mandate was further reinforced and extended by Section 29 and Section 30 of the Water Services Act, (Act 108).

This enables Magalies Water to provide solutions for all Water Services Authorities (WSA) within its area – for both core and non-core related business activities. In addition to O&M, this includes management services and training, as well as catchment management.

Crocodile West Catchment Water Resource Management Project A prime example of the latter is the Crocodile West Catchment Water Resource Management Project, which includes the Hartbeespoort Dam, where Magalies Water has been appointed

by DWS for a 36-month term. Included within the scope is the profiling of the water quality, the removal of invasive vegetation, and the implementation of remediation technologies to restore the dam’s natural water balance.

So far, results obtained from the Magalies Water Scientific Services Laboratory (ISO/IEC 17025:2017 accredited) have confirmed a wide range of contaminants that include the presence of E. coli, ammonia and orthophosphate. Aside from the environmental threat, these and other pollutants negatively affect the cost of Magalies Water’s downstream treatment costs, especially for its Vaalkop water treatment plant, which is currently the largest in its network, producing some 270 Mℓ daily.

However, as Mkhize points out, the issues affecting Hartbeespoort Dam are part of a much broader problem nationally to address rising water pollution concerns within riverine systems.

The way forward

“One of my major focus areas as CE is to smoothly streamline the amalgamation of Magalies Water and Sedibeng Water. Working with the Magalies Water board of directors, proposed and accepted recommendations will shape the future operational strategy,” says Mkhize.

“Our objective is to provide quality bulk water, sanitation and other related services to our public and private sector stakeholders using the most efficient fit-for-purpose technological processes. Examples include lower cost chlorine dioxide purification – where applicable – and energy efficient variable speed drive motors for our treatment plants,” says Mkhize.

Prior to its dissolution, Sedibeng Water (established in 1979) serviced parts of the North West, Free State and Northern Cape, Sandile Mkhize, Chief Executive, Magalies Water the latter two regions now

12 IMIESA October 2023

INDUSTRY INSIGHT having been absorbed by Bloem Water. In turn, Magalies Water’s assets and operations in Gauteng will be transferred to Rand Water, with Lepelle Northern Water taking over the current operations managed by Magalies Water in Limpopo. That places Magalies Water in a prime position to focus exclusively on North West.

New district municipalities added The three district municipalities in North West previously managed by Sedibeng Water and now part of Magalies Water are Dr Ruth Segomotsi Mompati, Ngaka Modiri Molema, and Dr Kenneth Kaunda. The first two are WSAs. The exception is Dr Kenneth Kaunda District Municipality where their local municipalities are WSAs, but not the district municipality itself.

“Across the country, organisational changes will ensure that each reconfigured water board is in a much stronger position to drive service delivery – particularly in support of undercapacitated municipal WSAs – in the quest to ensure Blue and Green Drop audit compliance, and self-sustaining entities,” Mkhize continues.

“Water provision is a national competency, but service delivery happens at a provincial and municipal level. In this respect, Cogta in North West is a key stakeholder where it’s important that we as Magalies Water are aligned with their expansion plans within municipalities in terms of infrastructure and human settlement development. Our Bulk Infrastructure Master Plan must be in synch with each respective Municipal Water Service Plan regarding reticulation expansion. And these systems must be affordable for end users.”

Magalies Water also engages extensively with its private sector clients in segments like agriculture, mining and tourism to understand and meet their bulk water supply requirements, steered by its Capital Investment and Stakeholder Committee, which also meets with WSAs twice a year.

Wastewater and sanitation options Going forward, Magalies Water’s mandate will now also include regional sanitation scheme rollouts and central control of wastewater treatment plants to ensure uniform standards.

Magalies Water currently has O&M agreements in place and will be expanding this service.

Examples include an agreement with Ngaka Modiri Molema District Municipality to operate some of their wastewater treatment works. These O&M arrangements include local capacitation and skills transfer.

Mkhize says a major objective is to eliminate the long-drop system and minimise the use of Ventilated Pit Toilets – particularly in rural

villages – by progressively phasing in waterborne sanitation services.

In the interim, he says there are excellent dry sanitation options published by the Water Research Commission that could also be implemented in smaller villages where waterborne sanitation may not be currently feasible.

“Our wastewater drive will also tie in with our overall reuse strategy, so that we can channel back treated effluent to near potable standard for industrial and agricultural applications – both at commercial and community scale – thus helping to preserve our scarce water resources within the province,” Mkhize explains.

The expanding network One of Magalies Water’s major projects at present is the upgrade of the Bospoort system, which supplies water to Rustenburg Local Municipality. This refers specially to the Mafenya Pumping Station and Pipeline to Thlabane Reservoir project. The latter represents Phase II of Magalies Water’s ongoing expansion and upgrade programme forming part of the Pilanesberg Bulk Water Supply Scheme.

Phase I entailed the installation of a 42 km pipeline completed in 2016, extending from Evergreen at the Vaalkop water treatment plant and culminating at Mafenya Reservoir. Phase II travels a further 28 km from the Mafenya Reservoir – situated some 5 km from Sun City – through to the Mafenya pump station for onward transfer to the 30 Mℓ Thlabane Reservoir in Rustenburg. Completion is scheduled for the end of 2023.

An allied project is the Moretele South Scheme.

Here the scope includes the construction of a

30 km steel pipeline from the Klipdrift Water Treatment Works in Hammanskraal to Moretele Local Municipality, which is expected to be completed by November 2024. The municipality forms part of the Bojanala Platinum District Municipality in North West.

Following the completion of some 52 km of pipeline in the first phase, a further 36 km is being installed to join up with the areas of Far West and Mogogelo in Moretele Local Municipality. A 25 Mℓ reservoir is currently under construction to act as a buffer system.

In closing “As the custodians of water and wastewater in North West, we have appointed a service provider to update our Bulk Water Master Plan to include the three district municipalities inherited from Sedibeng Water. Once concluded, we will then approach our shareholders to source the funding for identified priority projects,” adds Mkhize.

“The upside is that studies confirm there’s more than sufficient water within the Crocodile West and the Vaal River catchments to meet future provincial demand for all communities,” Mkhize concludes.

www.magalieswater.co.za

IMIESA October 2023

13

Next-level connectivity. Groundbreaking mobile solutions.

Telkom Naledi Gold

Telkom Naledi Platinum

• Uncapped data • 20GB streaming data • Unlimited Closed-User Group Minutes (Telkom-to-Telkom calls including Telkom landline) • 200 Other-Network Minutes • Unlimited SMSs • SIM-only R350 • Mobile service with mobile device

• Uncapped data • 20GB streaming data • Unlimited Closed-User Group Minutes (Telkom-to-Telkom calls including Telkom landline) • 600 Other-Network Minutes • Unlimited SMSs • SIM-only R500 • Mobile service with mobile device

Telkom Data Packages - Mobile Data (Roaming-enabled) Product Name

Anytime Inclusive Data

Night Surfer Data

Total Data

Mobile Data 1GB

1GB

1GB

2GB

Mobile Data 2GB

2GB

2GB

4GB

Mobile Data 4GB

4GB

4GB

8GB

Mobile Data 6GB

6GB

6GB

12GB

Mobile Data 10GB

10GB

10GB

20GB

Mobile Data 14GB

14GB

14GB

28GB

Mobile Data 20GB

20GB

20GB

40GB

Telkom Roaming Data • On-Net and Off-Net Data • Includes Night Surfer Data • LTE-capable

Telkom Only Data Packages (On-Net) Product Name

Bundle Size (GB) Anytime

Mobile Data 5GB

5GB

5GB

10GB

Mobile Data 10GB

10GB

10GB

20GB

Mobile Data 20GB

20GB

20GB

40GB

Mobile Data 40GB

40GB

40GB

80GB

Mobile Data 60GB

60GB

60GB

120GB

Mobile Data 80GB

80GB

80GB

160GB

Mobile Data 120GB

120GB

120GB

240GB

Mobile Data 220GB

220GB

220GB

440GB

Smart Broadband

• Telkom Roaming Data • On-Net and Off-Net Data • Includes Night Surfer Data • LTE-capable

Uncapped All Hour

Bundle Size (GB) Night Surfer

Total Data

Book an appointment for the full presentation.

Email us at RT15enquiries@telkom.co.za

Smart Broadband Uncapped Business Hours

• Telkom Roaming Data • On-Net and Off-Net Data • Includes Night Surfer Data • LTE-capable

Elevate your business with Telkom APN, RBU and Bulk SMS solutions.

APN

Bulk SMSs

RBU

• Offer your staff data to work from the office, and remotely.

• Our partner, Mobile Messaging, is built for and operates a powerful SMS marketing platform for high-volume SMS delivery and reporting.

The platform processes more messages per second, successfully delivering millions of marketing messages each day for clients.

• Use the Telkom RBU solutions to offer your customers free access to your selected websites.

• A managed end-to-end solution that offers security protocols.

• Use the Telkom APN for your telemetry requirements – water and electricity metering.

• Preferential rates for RT15-Corporate.

• Preferential rate for RT15.

Fixed to Mobile Convergence App • Easy-to-use smartphone app downloadable from the App Store for IOS and Android.

• Closed-User Group - all internal calls will be free over PSTN. • Uses mobile data to make and receive calls.

• Full Unified Communications functionality.

• Keep existing PBX numbers.

• Standard PBX features, such as: • Auto Attendant • Music on Hold • Telephone Management System • Call Forward • Call Transfer • Call Park • Voicemail

Book an appointment for the full presentation.

Email us at RT15enquiries@telkom.co.za

TRENCHLESS TECHNOLOGY

Considerations when designing linings for rehabilitating existing pipelines

U

nlike nature’s water cycle any manmade system has to be planned, designed, constructed, operated, maintained and, within a relatively short time, it needs to be rehabilitated to continue providing the service required. Whether it is a gravity or a pressure system, there are four basic requirements that have to be met, both initially and when rehabilitated, namely hydraulic performance, strength, water tightness and durability.

What happens over time

The water supply and wastewater disposal systems of mankind can be compared to the natural water cycle. In the case of water supply, there are the bulk or transmission pipelines, distribution pipelines and reticulation pipes. The wastewater disposal system operates in reverse order; reticulation, collection and outfall pipelines. Water supply generally operates as a pressure system; disposal systems as a gravity system.

By Alaster Goyns Pr Eng*

16 IMIESA October 2023

Due to increasing urban populations, the primary pipeline requirement of hydraulic performance changes over time. When the capacity of an aging pipeline needs to be increased to meet future demand, the ability to meet the other requirements may also have deteriorated and need attention. Frequently, even if its capacity is adequate, the other requirements may need attention. Hence there are two situations to consider with trenchless pipeline rehabilitation. When only the secondary requirements need attention, relining is used; but when all the requirements need attention, online replacement is used. With both sets of techniques, the watertightness and corrosion problems are addressed.

When choosing the most appropriate technique for a particular pipeline, the hydraulic and structural requirements therefore need to be evaluated.

Installation of a spirally wound lining (SWP) system on the Cape Flats 1 sewer line in Cape Town

TRENCHLESS TECHNOLOGY

Before and after perspectives of a corroded sewer line refurbished using cured-in-place lining techniques

flowing full, the total energy gradient is used but, when flowing partly full, the invert gradient is used.

With pressure pipelines, the whole pipeline flows full; with gravity systems, which generally flow partly full, the invert gradient is used and, for any sections which are flowing full, the energy gradient is used. This means that with a gravity pipeline where the invert gradients vary along its length, the flow velocities and flow depths will also vary along its length and sections may flow full or partly full. Under these conditions, the variability in velocity can result in deposition and blockages occurring in those downstream sections with low velocities due to flatter gradients than those of upstream sections.

Aged pipelines needing rehabilitation frequently consist of pipes that have been jointed. This means that over time there may be joints that have opened and become misaligned. This, together with the materials from which these pipes were made, means that the host pipe may have a bore that is significantly rougher than the material to be used for rehabilitation. Hence, when comparing the hydraulics of the deteriorated pipeline with that of the rehabilitated pipeline, both the internal diameters and the roughness of the host pipe and the lining needs to be taken into account.

Hence the actual performance of the rehabilitated pipeline relative to the host pipeline can be determined from equation [3].

In addition to these theoretical aspects that need attention when rehabilitating pipelines, there are several other factors that need consideration, including the site conditions, social and environmental impact, which are now receiving far more attention.

Pipeline hydraulics The simplest way of calculating pipeline capacity is by combining the Manning and continuity equations: [1] V = (1/n) x (R)2/3 x S1/2 [2] Q= AV = (A/n) x (R)2/3 x S1/2

Where V is velocity in m/s n is Mannings roughness coefficient R is hydraulic radius = A/P A is the flow area in the conduit in m2 (for pipe flowing full A = (πD2)/4) P is the wetted perimeter in the conduit in m (for pipe flowing full P = πD) S is the conduit gradient When a pipeline is flowing partly full, the same equations are used with the values of A and P adjusted for the flow depth. The gradient used in these calculations depends on whether the pipeline is flowing full or partly full. When

Qr /Qh = (Dr/Dh)8/3 x (nh /nr)

[3]

Where Qr, Dr and nr are capacity, internal diameter and internal roughness of the rehabilitated pipeline Qh Dh and nh are capacity, internal diameter and internal roughness of the host pipeline

Structural requirements The structural requirements for a pipeline or lining to handle external forces to prevent buckling and those required to

IMIESA October 2023

17

TRENCHLESS TECHNOLOGY

In addition to this, the structural condition of the host pipe will affect the performance of the lining. The lining in a partially deteriorated host pipe will fit tightly within the host pipe, which will enhance its ability to resist the groundwater pressure.

However, with a fully deteriorated host pipe, this reduction in water pressure is not taken into account and it is assumed that the liner has to take the full external load from the earth and ground water above it with no assistance from the host pipe.

Lining of pipelines

The structural requirements for a pipeline or lining to handle external forces to prevent buckling and those required to handle internal pressures to prevent bursting differ significantly. handle internal pressures to prevent bursting differ significantly. The buckling resistance is dependent upon the wall thickness to the power of 3, whereas the internal pressure is directly related to the wall thickness. This is shown in the formulae to be used for the two different loading cases.

For external loading the critical buckling pressure is calculated from: Pc = {(24ELI/D3 )/(1 - ʋ2)} x (C/N)

[4]

Where Pc is the critical buckling pressure in MPa EL is the long-term modulus of elasticity for the pipe material in MPa I is moment of inertia of pipe wall = t3 /12 t is minimum pipe wall thickness in mm D is mean pipe diameter in mm ʋ is the Poisson’s ratio for the pipe or lining material C is an ovality correction factor N is safety factor usually taken as 2 With a lining inside a host pipe, the external loading that causes buckling will be the water pressure between the host pipe and the lining. Equation 5 assumes that the lining is freestanding and not restrained by any external forces. However, linings in host pipes

18 IMIESA October 2023

will be restrained and the extent of this will be determined by how tightly the lining fits into the host, or whether the gap between the liner and host is filled with material that will add suppor t to the liner, in the same way that the bedding suppor ts a pipeline placed in an open trench.

Taking this factor and the value of I = t3/12 into account equation [4] can be rewritten as equation [5].

Pw = {(2KEL ) x (t/D)3/(1 - ʋ2)} x (C/N) [5] Where Pw is the ground water pressure at the lining invert in MPa K is an enhancement factor of the soil and the existing pipe to the lining The other factors are defined below equation [4] The value of K will depend on the particular lining used and how tightly it fits in the host pipe.

For internal pressure, it is the direct tensile stress, called the hoop stress, that resists the internal pressure. This is calculated from: σ = (pD)/(2t)

[6]

where σ is circumferential hoop stress in pipe wall p is internal pressure in pipe D and t are as defined above To determine the structural requirements of a pipeline to handle internal pressure, the same approach will be taken irrespective of the pipe material being used. However, when determining these requirements to handle the external loads, there is a clear distinction between the approach taken depending on whether the pipes are rigid or flexible.

There are several lining techniques used for the rehabilitation of deteriorated pipelines. In South Africa to date the techniques generally used are sliplining, cured-in-place pipe, and spirally wound liners. However, several other techniques could be used as well, such as fold and form, swage and panel linings. The choice of technique will depend upon which of the functional requirements have not been met by the existing pipeline and what the site constraints are. These can be determined only by assessing the performance and condition of the pipeline by doing an internal inspection, identifying the subsurface soil conditions, and establishing the surface developments along the pipeline route.

The simplest lining technique is sliplining where a new pipeline with an external diameter smaller than the internal diameter of the deteriorated host pipeline is pulled into the host pipeline. As the one is pulled into the other, this would be a loose fit with a gap between the host and the liner. This gap may later be filled with grout. If the roughness of the host and liner were equivalent, then equation [3] would reduce to the ratio of (Dr/Dh)8/3.

The most frequently used liner is polyethylene (HDPE) pipe. This is usually a 10 bar pressure pipe as it has sufficient strength for the pulling device to be attached to it. In most situations it has far more strength than needed to handle either the internal pressure or external load to which it would be subject under service conditions.

The typical ratio of the internal diameters of concrete sewer pipes with those of the pipe to be used as a liner would be about 0,75. This means that the liner would have a capacity of

TRENCHLESS TECHNOLOGY

only about 46 % of the host pipeline.

However, the deteriorated host pipe could have a roughness significantly higher (1,3 to 1,5 times) than that of the liner, which means that the full flow capacity of the rehabilitated pipeline could be between 60 % and 70 % of the deteriorated host pipeline.

Under certain situations with sewers where this happens over a short section only, this may result in a section of sewer flowing full, but not actually causing any serious surcharging and overflowing of manholes under peak flow conditions.

The practicality of using sliplining under these conditions may well be an acceptable approach.

When sliplining cannot meet the hydraulic requirements, there are several modified forms of this which are close fit lining solutions, such as swage and fold and form linings. These fit tightly into the host pipe maximising the lining bore. When HDPE pipe is used for either of these processes, the ratio of the host pipe diameter to that of the lined pipe will be about 0,86 and, when the impact of this with the smoother bore of the lining is taken into account, the capacity will be about the same as that of the original host pipe. When a fusible PVC pipe is used for fold and form, there may be a slight improvement in the hydraulic capacity. These two techniques can be used for either gravity or pressure systems.

When a cured-in-place pipe lining is used, the rehabilitated pipeline will have an increase in capacity. With the

The densification in urban areas means there are serious space constraints and the traditional approach of digging trenches to replace pipelines in these areas is seriously disruptive to residents and businesses. spirally wound solution, the capacity will be similar to that of the pipeline before rehabilitation.

The trenchless techniques for pipeline rehabilitation using linings to reinstate their structural, watertightness and durability requirements are similar whether they are gravity or pressure systems. However, differences need to be considered when doing the structural design of the lining to be used.

The major difference is due to the loading cases to be considered. With gravity systems the lining needs to be designed for the groundwater pressure that develops between the liner and host pipeline due to leaks into the system, so that it does not buckle under the maximum value of this pressure when the pipeline is empty. For pressure systems, the liner must be designed for the maximum internal pressure, as well as for external pressure which may occur when the pipeline is empty.

Online replacement of pipelines With the rapid urbanisation taking place in South Africa, there are many serviced areas where the water supply and wastewater disposal pipelines do not

have the capacity to meet the demand.

Relining the existing pipelines improves their strength, water tightness and durability but does not address their primary function of hydraulic capacity.

In addition, the densification in urban areas means there are serious space constraints and the traditional approach of digging trenches to replace pipelines in these areas is seriously disruptive to residents and businesses, and there is a danger of damaging surrounding buried services. Trenchless online replacement of these pipelines offers significant benefits, as the space requirements are significantly less, and the process takes place along the existing pipeline.

Pipe bursting is the simplest technique for the online replacement of deteriorated pipelines. It involves fragmenting the host pipeline by pushing it into the surrounding soil and simultaneously pulling in a new pipeline of the same or larger internal diameter as the pipeline being replaced. Another technique that has been used for online replacement in South Africa is pipe reaming, which uses a combination of pipe bursting and horizontal directional drilling. With this system, the drilling rig pulls the bursting device through the existing pipeline and simultaneously pulls in a new lining of a larger diameter.

Final comment The choice of technique depends on meeting the technical requirements, as well as the space constraints for rehabilitation. Certain of the techniques, such as cured-in-place pipe and spirally wound liners have smaller space requirements than most of the other techniques, and this has to be taken into consideration when choosing the most appropriate system for a particular project. *Board member, Southern African Society for Trenchless Technology

IMIESA October 2023

19

GEOMATICS

Land surveyors – the pioneers of precision For those well-versed in the complexities of infrastructure projects, we understand that success lies in the details. One such detail, frequently underestimated, is the critical support role of land surveyors, writes Chris Kirchhoff, a Professional Land Surveyor and chairman of the South African Geomatics Institute’s Northern Provinces branch.

I

n a muti-faceted built environmental where precision, risk mitigation, and regulatory compliance intersect, land surveyors form the bedrock of every project, yet their contribution is often overlooked in the project cycle. However, their work does generate value and mitigates risks – from engineering, property ownership and land legal perspectives. No client wants to face costly rework and adjustments down the line.

In South Africa, land surveyors adhere to both the Land Survey Act 8 of 1997 and the supporting regulations – which regulates the survey of land and real rights in land – and the Geomatics Profession Act 19 of 2013, which sets out professional standards and

20 IMIESA October 2023

controls who may practice as a land or engineering surveyor.

Geospatial information

The foundation of any infrastructure project is accurate geospatial information.

Here land surveyors are the experts in acquiring and interpreting this data, providing an essential roadmap for design, planning, and precise implementation.

The geospatial data they collect and analyse can uncover potential issues long before they become problematic.

For example: - Are there restrictive title deed conditions or municipal zoning issues?

- Are there boundary encroachments?

- Does the topography lend itself to development?

- Is the proposed construction site on a floodplain?

- Are there any underground utilities that could interfere with the project?

Land surveyors are specifically qualified and empowered by legislation to answer these questions at feasibility study level, thereby preventing expensive and potentially dangerous surprises later in the project cycle – but more critically at preconstruction stage.

Additionally, accurate geospatial information is required for assessing the potential environmental impact A LiDAR drone team of an infrastructure project. This make preparations for enables developers to design and take-off on a mapping implement their projects in a way infrastructure that minimises harm and aligns upgrade survey with sustainability goals.

It’s not as simple as dispatching a drone – unmanned aerial vehicles are great tools, but their job is to collect data, not make sense of it.

Guardians of compliance One of the most essential areas where land surveyors play a crucial role is in ensuring cadastral and town planning regulatory compliance. Local laws and town planning regulations dictate specific requirements for infrastructure projects, from boundary regulations to floor area ratios to environmental impact assessments.

Here, the land surveyors’ expertise helps developers navigate this complex regulatory landscape, ensuring that projects comply with all necessary guidelines and avoid legal entanglements or delays.

NATIONAL CONTACTS South African Geomatics Institute (SAGI) Branch and Chairman • KwaZulu-Natal Riaan van Jaarsveld Email: kzn.chairman@sagi.co.za • Eastern Cape Ivan Hansen Email: ec.chairman@sagi.co.za • Northern Provinces (Gauteng, Limpopo, Mpumalanga, North West) Chris Kirchhoff Email: np.chairman@sagi.co.za • Northern Cape/Free State Deon van Zyl Email: fsnc.chairman@sagi.co.za • Western Cape Matthew Stuart-Fox Email: wc.chairman@sagi.co.za www.sagi.co.za

GEOMATICS

Finance and asset management Then there’s the financial element, considering that a large portion of local government revenue needs to be sourced from property taxes. Where illegal building extensions occur, for example, that translates into lost revenues. Using a range of tools that include drone mapping and GIS software, land surveyors are equipped to verify and confirm that all plans are accurate, updated and recorded with the municipality and the Surveyor General’s office.

Another core area which speaks to finance is asset management in terms of budgeting for operations and maintenance, and utility billing (like water and effluent).

It all boils down to helping clients manage their facilities (like schools) and assets (like roads) more efficiently. Often clients no longer have access to the original as-built plans. That makes it really challenging for major assets to be remodelled or upgraded.

BIM As with other professional disciplines like architecture and engineering, land surveyors have embraced the advantages of building information modelling (BIM) software to create the so-called digital twin – a virtual rendition of the real world.

The 3D model evolves with the importing of data and in expert hands is an amazing tool for the design, construction and future

A BIM rich 3D Revit model extract of an office building interior

lifecycle management of any building or infrastructure asset. Costs and quantities can also form part of the model.

Essentially, BIM is the hub of the wheel that connects all professionals. For this reason, it should become a far more commonly adopted platform – especially for private and public sector team engagement when planning and executing infrastructure developments. With the land surveyor on board, everything gets built in the right place. Plus, the technology

enables clients to virtually “walk through” the model.

In closing Exact measurements are non-negotiable in engineering, but it’s clear that the land surveyor’s role is far more complex than this.

Their knowledge and talents boost efficiency and safeguard against risks, making them indispensable for future-proof development in our geospatial world.

A 3D point cloud rendition of a wastewater treatment works captured for use in 3D Revit model preparation

IMIESA October 2023

21

CONSULTING ENGINEERS

T

The Design of Infrastructure for KwaShushu Hotspring and Ntunjambili Mountain Tourism Project in Maphumulo Municipality

VALUE ENGINEERED SOLUTIONS FOR MUNICIPAL SERVICE DELIVERY Since its formation in 2011, M & C Consulting Engineers (M & C) has established a strong presence within the KwaZulu-Natal region.

Construction of Chibini Access Road in Ward 4 of Ndwedwe Local Municipality

22 IMIESA October 2023

he firm’s technical and administrative experience spans a broad spectrum of civil infrastructure development (transport, water, educational, leisure, residential and social projects) undertaken for the private and public sector (municipal, provincial, and national government). Its capabilities span planning, design, implementation, project management, commissioning, and maintenance.

“A review of some of our past and recent projects underscores our diverse offering within the civils and building sector, where we are committed to value engineered and fit-for-purpose solutions,” explains Sinenhlahla Chamane, M & C’s chief executive officer.

“The provision of water and safe sanitation remain priorities, plus there’s a pressing need to combat potable pipe leakages that contribute towards non-revenue water losses, as well as sewage leaks that cause groundwater contamination.”

Examples of work in this area includes the refurbishment and upgrade of wastewater works and sewer pipelines

PROVEN ENGINEERING SOLUTIONS M & C was responsible for overseeing the refurbishment and upgrade of wastewater works and sewer pipelines in Mtubatuba for the Umkhanyakude District Municipality

in Mtubatuba for the uMkhanyakude District Municipality.

Completed in May 2022, the project scope was extensive and covered five different locations within Mtubatuba Local Municipality. These comprised Mtubatuba’s central business district, Ndlovu Village, Msane Township, Nordale Township and the town of St Lucia.

Some years prior to this project, M & C also completed a threeyear water loss management intervention for King Cetshwayo District Municipality as CPG for Beyond InfraDev. The scope included the installation of advanced controllers on selected PRVs; meter repair, replacement, and installation; mains and reticulation leak detection surveys and repairs; domestic leak repair and domestic plumbing retrofitting programmes; meter auditing and converting meters to prepaid.

M & C Consulting Engineers is a multidisciplinary civil engineering consultancy firm based in KwaZulu-Natal. The company is a 100% black female owned and managed firm. M & C Consulting Engineers prides itself on a high level of quality assurance and holds ISO 9001:2015 accreditation.

Buildings Another segment where M & C leverages its turnkey solutions in the design and construction supervision of a wide range of buildings – from earthworks, brickwork, to installation of electrical, water and sanitation services. Examples include the Design of Infrastructure for KwaShushu Hotspring and Ntunjambili Mountain Tourism Project in Maphumulo Municipality.

Roads and services Other recent contracts include the construction of Chibini Access Road in Ward 4 of Ndwedwe Local Municipality, which reinforces M & C’s multi-disciplinary expertise. The project included clearing and grubbing, bulk excavation, mass earthworks, pavement of layers of gravel material and various stormwater interventions.

The latter include drainage pipes, culverts with gabion wingwall protection, and V-drains.

Prior to the implementation of the project, the main surfaced access road had suffered continual erosion due to poor drainage, as well as improper cambering, resulting in ponding and subsequent potholes.

“These are just snapshots of some of our projects. Currently, we’re busy with various gravel road upgrades – so essential for rural communities – as well as recreational projects that include a sports field. These and other projects in the pipeline are all geared towards enabling municipalities to deliver best-in-class infrastructure and facilities,” Chamane concludes.

OUR SERVICES: • Civil and Structural Engineering • Roads and Transportation • Stormwater Management • Water & Sanitation • Municipal Engineering • Municipality Support Systems (including MIG projects) • Electrical Engineering

• Construction Monitoring & Project Management • Construction of Sports & Recreation Facilities (including communal swimming pools, sports grounds, etc.)

• Housing Infrastructure Planning, Design & Construction Monitoring

Head Office: 335 Ebony Crescent, Mtubatuba, 3935 Branch Office: 9 Dan Pienaar Road, Kloof, 3610 035 550 0231 | 031 764 3728 | 061 402 5418 info@mcconsulting.co.za www.mcconsulting.co.za

PROUD MEMBERS OF IMESA

Aim higher and connect more with Telkom Naledi packages.

Elevate your team to new heights with exclusive Telkom Naledi packages that offer great office connectivity solutions and value.

Book an appointment for the full presentation.

Email us at RT15enquiries@telkom.co.za

Aim higher and connect more with Telkom Naledi packages.

RT15 Exclusive Offers

Telkom Naledi Gold • Uncapped data • 20GB streaming data • Unlimited Closed-User Group Minutes (Telkom-to-Telkom calls including Telkom landline) • 200 Other-Network Minutes • Unlimited SMSs • SIM-only R350 • Mobile service with mobile device

Telkom Naledi Platinum • Uncapped data • 20GB streaming data • Unlimited Closed-User Group Minutes (Telkom-to-Telkom calls including Telkom landline) • 600 Other-Network Minutes • Unlimited SMSs • SIM-only R500 • Mobile service with mobile device

Book an appointment for the full presentation.

Email us at RT15enquiries@telkom.co.za

Advantages Uncapped data with no FUP applied to the package. Data access will never be terminated or stopped. Includes WhatsApp. Telkom Naledi packages come with a dedicated streaming bundle for YouTube, Facebook, Facebook Messenger, Twitter, Instagram, LinkedIn and WhatsApp. Network-based CUG. Telkom is the only company that offers this converged voice-call solution across fixed and mobile numbers, which will result in significant voice-calling savings.

State users on Top-Up options can top up their all-net minutes at the discounted State OOB rate of R0.45 (36% discount).

Full allocation of all package bundles and benefits even if a SIM is activated mid-month.

No proration is applied – as we would do normally.

Event billing and premium-rated events can be blocked at a SIM level, backed by the setting of a zero spend limit.

INFORMATION & COMMUNICATIONS TECHNOLOGY

Responsible and ethical AI process automation has its part to play To some it might feel like we’re living in an “endless summer” of ar tificial intelligence (AI), with a new breakthrough announced almost monthly. By Hennie Colyn

A

nd while AI offers important benefits to a myriad of industries, it should also be a cautionary tale, with the relevant cybersecurity, legal compliance, data protection and so forth measures put in place.

In the case of process automation, AI undoubtedly has its part to play, adding an important layer of intelligence. By using machine learning (ML) and complex algorithms to analyse structured and unstructured data, businesses can use the decision-making engine of AI to develop a knowledge

Hennie Colyn, direct sales executive: Process Automation at Schneider Electric

26 IMIESA October 2023

This approach ensures a more accurate forecasting model and provides explanations for consumption patterns.

Therefore, if unusual conditions occur, user-validated suggestions for relearning can be incorporated to improve system behaviour and avoid models biased with overrepresented data.

Responsible AI base and formulate predictions based on said data.

Where process automation works with data, AI interprets it, whether historical or current, to uncover trends, make predictions or suggest optimal courses of action. All this offers intelligent decision support to businesses, helping them deliver failproof and future focused strategies that propel business growth.

An intelligent partnership, with conditions AI experts and data scientists are often at the forefront of ethical decision-making: detecting bias, building feedback loops, running anomaly detection to avoid data poisoning – in applications that may have far reaching consequences for humans.

They should not be left alone in these critical endeavours.

To select a valuable use case, choose and clean the data, test the model, and control its behaviour, you need both data scientists and domain experts.

For example, take the task of predicting the weekly energy consumption of an office building. Here the combined expertise of data scientists and field experts enables the selection of key features in designing relevant algorithms, such as the impact of outside temperatures on different days of the year.

Keeping this in mind, Schneider Electric has taken a three-pronged approach to the way we develop AI solutions, namely: • Compliance with laws and standards, like our Vulnerability Handling & Coordinated Disclosure Policy, which addresses cybersecurity vulnerabilities and targets compliance with ISO/IEC 29147 and ISO/ IEC 30111. At the same time, as new responsible AI standards are still under development, we actively contribute to their definition, and we commit to comply fully with them.

• Our ethical code of conduct as outlined in our Trust Charter. Our strong focus and commitment to sustainability translates into AI-enabled solutions accelerating decarbonisation and optimising energy usage. We also adopt frugal AI – we thrive to lower the carbon footprint of ML by designing AI models that require less energy.

• Our internal governance policies and processes. For instance, we have appointed a digital risk leader and data officer, dedicated to our AI projects.

We have also launched a Responsible AI workgroup focused on frameworks and legislation in the field, such as the European Commission’s AI Act or the American Algorithmic Accountability Act, and we deliberately choose not to launch projects raising the highest ethical concerns.

From unwanted to wanted

With close to 45 years of experience in the waste management industry, collaboration with customers is how we drive the circular economy.

We implement agile and innovative waste solutions, proudly ensuring environmental peace of mind through our commitment to industry standards. www.enviroserv.co.za | 0800 192 783 FIND OUT MORE

ENVIRONMENTAL ENGINEERING

Minimise harm to the environment with bioremediation Bioremediation of soil is an alternative to a landfill option and one that is most effective in larger volumes due to the equipment and time required to achieve the desired result. The process uses living organisms, like microbes and bacteria to remove contaminants.

E

nviroServ’s industrial services manager, Henco Swart, says two types of soil remediation are possible, namely in-situ – the treatment of contaminated soil where it lies – and ex-situ, where it is excavated and taken to a suitable area for treatment.

“The treatment method is the same for both – application of bioremediation agents and nutrients to the soil, which is watered to the correct level and aerated to introduce oxygen, before being monitored as the good bacteria grow,” Swart explains.

“We then maintain a healthy environment for these good bacteria to do their job of reducing contamination. However, remediation is not always possible, and the length of time it takes to achieve the desired results depends on the level and type of contamination.”

The key question is, once the desired level of remediation is achieved, can the remediated soil be reintroduced to the area where it came

Bioremediation is not always possible, and the length of time it takes to achieve the desired results depends on the level and type of contamination

cheapest option. This is a win for the environment.”

Active site limitations

from? In this respect, successful remediation can be confirmed through verification analysis at an independent laboratory.

“In certain cases, remediation is costeffective but due to the zero waste to landfill drive, EnviroServ has seen increased numbers of requests to assist companies in achieving these goals even when it is not the

But Swart says soil remediation cannot be done on an active site, “as this would lead to recontamination.” In-situ remediation usually takes place in areas that can be isolated for the remediation period.

“There are legal protocols that need to be followed during remediation, which EnviroServ is well versed in. The remediation plan required for each project is determined by data collected from sources, such as a waste analysis and a detailed assessment of the contaminated area,” Swart concludes.

For expert advice and assistance visit www.enviroserv.co.za.

The bioremediation process uses living organisms, like microbes and bacteria, to remove contaminants from the affected soil

28 IMIESA October 2023

WATER & WASTEWATER

MAINTAINING KIKUYU THE WATER WISE WAY

Lawn and other turf grasses are often seen as highwater users, especially in the spring and summer seasons before the rainy season has started. But can lawn be used in a water wise way? Water Wise explains the wise use of water with kikuyu.

Kikuyu Pennisetum clandestinum, commonly known as kikuyu, is the most widely used lawn grass in South Africa. It is native to East Africa and has an aggressive growth form, which means it can become invasive and take over indigenous grasses.

Kikuyu is drought tolerant, inexpensive, and easy to maintain because it can grow in areas where most grasses cannot.

However, it is sometimes considered the highest user of water in comparison to other commonly used turf grasses.

Kikuyu is mostly used as an instant lawn for sports fields, golf course construction, and rehabilitation. It has a mat root and an herbaceous growth habit. It doesn’t grow well in shaded areas.

Dormancy in lawn Dormancy refers to a period where growth of the grass temporarily slows down, and grass goes into a resting state for one season. Kikuyu always goes

dormant during winter, where the grass will turn brown. However, brown kikuyu grass does not mean it is dead; it has simply gone dormant.

Dormant kikuyu does not need to be watered. Lawn in a state of dormancy is simply “resting” and conserving energy for the new growing season. Dormancy is a natural way for lawn to conserve moisture and nutrients in cold and dry seasons.

Water wise watering for kikuyu • Avoid watering kikuyu when it is dormant.

• Wait for the rains to start before awakening your kikuyu from its dormant state.

• Newly installed kikuyu will only require more water during its settling or establishment period. Gradually decrease the frequency of watering after this phase.

• In summer, water in the early morning or late afternoon as this reduces water lost to evaporation.

• Use a trigger nozzle if watering kikuyu with a hose.

Advantages of kikuyu • Fast growing.

• Grows in full sun and in most soils.

• High-traffic resistant and persistent growth form.

• Sur vives long dr y periods and is drought tolerant.

• Better frost tolerance than some warm season grasses.

• Very effective for erosion control in ornamental landscapes.

• Rapid summer growth rate with high yield potential.

•V ery competitive; suppresses weeds.

Disadvantages of kikuyu • Requires regular mowing.

• High evapotranspiration rate.

• Can be invasive and difficult to control.

There are many other simple ways you can save water. Visit the Water Wise website by going to the Rand Water website and clicking on the Water Wise logo for more information. Always be #WaterWise!

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

IMIESA October 2023

29

WATER & WASTEWATER

Navigating the complexity of water use licence applications To streamline the process of applying for water use licences, many companies work with specialised consultants to help them navigate its increasing complexity. With its extensive experience in this field, SRK Consulting offers some guidance on how best to manage this responsibility.

Avril Owens, principal environmental scientist at SRK Consulting

A

ccording to Avril Owens, principal environmental scientist at SRK Consulting, the process requires consultants to work as closely as possible with their clients, officials from the Department of Water and Sanitation (DWS), and with the various technical specialists who conduct the necessar y studies to inform the application.

“An important aspect of the process is to use the DWS Electronic Water Use Licence Application and Authorisation System (e-WULAAS),” says Owens. “This is the electronic system where data and reports are uploaded for the submission of a water use licence application.”

Giulia Barr, senior environmental scientist at SRK Consulting

Communication Owens notes that the implementation of the e-WULAAS has been a significant step for ward in streamlining the application process, as it replaces the printing and deliver y of numerous application documents to the relevant DWS regional offices, where these documents were stored and manually processed. The system allows for electronic uploading of documentation and assists DWS with tracking and reviewing the application. Key communication is also conveyed through the system.

“Structured and agreed upon communication protocols with DWS officials is vital, as they manage multiple applications which may impact on their availability to

address ad hoc queries regarding specific project requirements associated with an application,” explains Owens.

It is worth noting that requirements may differ slightly between the various DWS regional offices. It is therefore crucial that specific DWS requirements are outlined and agreed at the beginning of the process.

Giulia Barr, senior environmental scientist at SRK Consulting adds that, “It can also happen that the DWS case officer changes during the application, and communication is key to bring the new case officer up to speed, to provide context in assisting with the application review and approval within the timeframe.”

Gap analysis and strategic planning is important in the early stages of the water use licence application process

30 IMIESA October 2023

WATER & WASTEWATER

It is advisable that one person is identified to engage with DWS per project or per site to ensure continuity and avoid misalignment in terms of key requirements and feedback from DWS. “Once contact is made with the assigned DWS official for the specific water use licence application, agree on which medium is best to communicate through, and how often progress on the application can be obtained,” says Owens. “It is important that communication requirements between the client, consultant and DWS are defined and the agreed upon communication protocols followed to support a streamlined process.”

Consultants collaborate closely with clients, DWS officials, and technical specialists to navigate the complexities of water use licence applications

Share knowledge The water use licence application process does not only require that the relevant information is provided, but that it is in the correct format to meet DWS requirements.

Barr points out that the water use licence application process is prescriptive and relies on correct and appropriate information being provided. A key aspect is the sharing of specialist and engineering information

KEY HIGHLIGHTS It is vital to communicate well with all parties during a water use licence application process, advises SRK Consulting. This includes: • Structured and agreed upon communication protocols • Knowledge sharing • Proactive upfront planning • Understanding roles and responsibilities

generated for the project with the entire team to ensure integration of the relevant information in the supporting technical documents compiled for the application. “It takes significant effort and time to develop and integrate the necessar y information for an application where multiple water uses require authorisation,” says Barr.

It is beneficial to have specialist and technical integration workshops at key stages of the project to facilitate sharing and understanding of specific discipline needs and challenges.

A key role that consultants play in the planning phase of the application process is to share the specific requirements in terms of engineering, technical, specialist reporting and lessons learnt from previous applications with the client, technical teams and specialists. This aids the planning of realistic timeframes and ensures stringent requirements are met.

“Changes affecting water uses and associated mitigation measures or changes to the project description and design once the application process has commenced can lead to complications, as these can affect the specialist assessments, delay schedules and increase costs,” says Owens. “It is advisable that a scope freeze be agreed upon upfront and signed off as the impact of these changes may be

challenging to mitigate and will lead to additional work.”

Owens, however, recognises that scope changes may result from the outcome of specialist studies. Therefore, it is advisable that, as far as possible, specialist studies that will have an impact on the identification of additional water uses be prioritised and completed before any phases on the e-WULAAS are undertaken.

Gap analysis Due to the water use licence application process often being lengthy, it is generally initiated in the early stages of a project – such as prefeasibility stage – where there is often insufficient information to meet application requirements.

“Environmental experts should therefore be consulted in the concept phase, so that environmental authorisation and water use aspects can be aligned during this phase,” adds Owens.

“It is advisable to start the water use licence application process with a gap analysis and action plan to assess what information is available and to determine a suitable way for ward, including a detailed schedule, and assigning roles and responsibilities to close identified gaps to meet the level of information required for the application,” Owens concludes.

IMIESA October 2023

31

WATER & WASTEWATER

UNEARTH THE HIDDEN LEAKS IN YOUR LANDSCAPE Water is among the world’s most valuable resources, yet it is also a universally mismanaged resource. As a result, water shortages are becoming ever more common.

L

eaks amongst others are the main factors that exacerbate water scarcity, which results from network failure caused by factors such as incorrect installation, lack of maintenance, aging infrastructure, and excessive water pressure. To reduce network failure, it is necessary to plan and budget for resources that will investigate and implement the necessary corrective steps to the water supply system.

Furthermore, the advancement in technology has led to the development of quick “leak detector” devices that enables a quick detection and location of leaks within the network system, including above all, the so-called hidden leaks, which are not visible as they rely on the leakage of water into the ground through gaps derived in impaired pipelines.

South Africa loses about 40% of its water through leaks and unaccounted for water. This triggers the need for landscape businesses to consider investing in a Smart Water concept as an innovative approach to improve efficiency and sustainability.

Equipment and technology Smart water systems use equipment and technology like sensors and control panels to detect and relay information about leaks and variation in water pressure. To assist with reducing the unnecessary water leaks each water offtake in the landscape should ideally be fitted with its own meter that is either monitored manually or via a smart

32 IMIESA October 2023

device (preferred), as smart metering can easily be integrated with irrigation systems.

This will help with early leak detection within the water supply or irrigation system.

Furthermore, it’s essential to consider other areas where water leakage could pose a significant problem. For instance, a constantly dripping faucet or a leaking toilet can result in an average daily water wastage of 30 to 60 litres. To address these issues and reduce water expenses, Water Wise provides straightforward DIY solutions, including: • Monitor your water usage: Reading your water meter at the beginning and at the end of each day/every month can help you gauge your household and business water consumption.

• Irrigation system leaks: If an irrigation head is steadily dripping water when the system is off, you may have a leaking valve underground or a worn diaphragm which needs to be replaced. It’s always best to call in the professional landscaper to step in and patch things up properly.

• Landscape inspection: It’s a good idea to periodically inspect your landscape for irrigation system problems, such as sunken ground which indicate an underground leak.

• Fixing leaking taps: Address tap leaks by replacing worn-out tap washers.

• Toilet leak detection: To check if your toilet is leaking, simply add approximately 4 to 5 drops of food colouring into the toilet tank/cistern. If you notice the colouring seeping into the bowl without flushing within 30 minutes, it signals the presence of a leak that requires immediate repair.

www.randwater.co.za

WATER & WASTEWATER

VERSATILITY IN DEWATERING FOR THE MOST DEMANDING JOBS

T

he Godwin BD150 Self-Priming Dri-Prime® pump series is designed to deliver in industriallevel dewatering and liquid bypass applications that include mining, construction, municipal, marine, and emergency response markets.

With its modular base design, the BD150 offers a range of mobility options, including skid, two-wheel trailer, four-wheel trolley, forklift pockets, and four-point lifting frame.

It is easy to transport and move – an excellent workhorse for ad hoc and temporary dewatering jobs, and well-suited for rental transactions. The BD150 series is also equally reliable for permanent jobs, providing

standard engine-driven (regional emission compliant) and electric motor-driven options.

BD150 pumps tackle challenging conditions, providing fully automatic vacuum or venturi priming (from dry to 8,5 m suction lift), and will handle sewage, slurries and liquids with solids up to 75 mm in diameter.

Flow capabilities range up to 592 m3/h and discharge heads up to 49 m.

Furthermore, these pumps provide default 150 mm/6 in suction flange and delivery connections, with optional adapters to accommodate different sizes.

Interchangeable impellers provide even more flexibility for different jobs. Additionally, abrasion-resistant silicon carbide faces, and

the optimised centrifugal hydraulic design, reduce wear and maintenance.

On the go, the simplified control panel with key start-stop, ammeter, hour meter and low oil pressure indicator streamlines operations.

Typical dewatering applications include: ● Wastewater bypass and stream diversions ● Digester cleaning and sludge removal ● Emergency drainage of floodwaters ● Site drainage ● Wellpoint dewatering ● Process pumping ● Temporary raw water supply, and ● Barge ballasting For further information, contact your Xylem partner representative.

Specialist Waste Management Consultants • Waste Collection Optimisation • Transfer Station Design • Material Recovery Facility Design • General Waste Landfill Design • Hazardous Waste Landfill Design • Landfill Closure and Rehabilitation Design • External Auditing of Waste Facilities

• Regional Waste Studies • PPP Involvement in Waste Management • Alternative Technologies for Waste Diversion • Integrated Waste Management Plans • Closure/Rehabilitation Cost Provisions

T: +27 (0)21 982 6570 F: +27 (0)21 981 0868

www.jpce.co.za 60 Bracken Street, Protea Heights Brackenfell, South Africa, 7560

P O Box 931, Brackenfell, 7561

WATER & WASTEWATER

Double Win

SBS Tanks brings water security to two communities at once

South Africa is known for its geographical beauty, wildlife and wide open habitats. But along with offering unparalleled experiences to tourists and adventurous city dwellers, the distribution of the countr y’s population across vast regions brings many challenges for both the people living far from city centres, and for the municipalities delivering ser vices such as water and electricity to these rural settlements.

T

he municipal mandate to deliver water to the people remains a priority, even for the most rural areas,” says Mava Gwagwa, director: New Business, SBS Tanks. “We recently collaborated with the Dr Beyers Naude Municipality and their team of professional ser vice providers on another successful project that will help bring water security to two communities in the Eastern Cape region.”

The Dr Beyers Naude Municipality, which includes what was previously known as

34 IMIESA October 2023

the Ikhwezi and Camdeboo municipalities, required additional bulk water storage for the Jansenville and Klipplaat communities.

Working with the Dr Beyers Naude Municipal team, consulting engineers, Gilgal Newground Joint Venture, and Mazangwa Construction, SBS Tanks delivered a cost and time effective bulk water storage

In Klipplaat, SBS Tanks installed an ST21-05 to deliver 775 kℓ of water storage for the area, supplied with a Sahara colour coated finish solution that fits seamlessly into the Karoo landscape. The project was funded by the Department of Water and Sanitation.

COLOUR OPTIONS FOR AESTHETICS, THERMAL OR SOLAR REFLECTANCE Water storage tanks have become a necessity, but they do not need to be an eyesore, especially as they age. In this respect, SBS Tanks has been offering a range of colour water storage tank options for more than two decades across its product range, which extends from 7 000 up to 4,2 million litres.

Commercial, municipal, residential, and agricultural clients want their water storage tank to either blend in with the natural surroundings or with the existing building or roof colour – or to make a bold statement.

Aside from aesthetics and compliance there are also other reasons for clients to choose colour coated water supply tanks. These include solar reflectance or light deflection, where the placement of the water storage tank may raise concerns about the light reflected off the tank into traffic, adjacent offices or businesses, sports fields or schools.

Thermal properties such as emittance could also be a consideration for the client, depending on where the tank is installed. Thermal emittance measures the ability of a surface to radiate any absorbed solar energy. The higher the thermal emittance, the faster the surface can cool following exposure to the sun’s rays. This is key in applications where maintaining the temperature of the water or liquid stored within the tank is important.

SBS Tanks offers a standard or custom range of colours. Whether it is a fire water tank solution, a back-up water storage tank, a rainwater harvesting tank, mine or municipal bulk water storage tank, SBS Tanks will deliver in the colour chosen.

WATER & WASTEWATER Jansenville In Jansenville, a bulk water storage tank from the SBS Tanks Standard Tank Range was installed to provide an effective 1,3 Mℓ of water storage capacity. The SBS Tanks’ engineering team designed a specialised ring beam, which was constructed on the existing concrete floor of the old reser voir. Several other design elements were required to ensure that the water, sourced from various boreholes, moved through to the supply tank free and clear of the naturally occurring sediment.

This included sloping the floor at a 3 degree angle towards the centre of the tank to propel the sediment towards the centrally positioned invert of the 250NB HDPE scour from where it is drained out of the tank. The fitment of a 50NB HDPE pipe serves to aerate the water inside the tank, further expediting settlement of the sediment. A second outlet, placed 2,5 m higher than floor level, ensures that the water leaving the tank is free of any sediment and particles.

Klipplaat In Klipplaat, approximately 30 km from Jansenville, SBS Tanks installed an

In Jansenville, a bulk water storage tank from the SBS Tanks Standard Tank Range was installed to provide an effective 1,3 Mℓ of water storage capacity, supplied in a chalk colour from the company’s powder coated range

ST21-05 to deliver 775 kℓ of water storage for the area. Again, due to space limitations, the SBS bulk water storage tank was installed on the floor of the old reservoir after contractors demolished the concrete walls.

“To help blend the tanks into the natural surroundings, and ‘match’ them to the existing concrete reser voirs, which they were installed alongside, the client chose colours from the SBS Tanks powder coated colour range. In Klipplaat the colour Sahara was used, and in Jansenville, the colour chalk.”

A comprehensive storage solution SBS Tanks, working with municipalities across South Africa, and into other regions in Africa, is able to deliver an ideal solution to the challenges faced by districts with widespread population settlements to ser vice.

“Our water storage tanks are constructed using lightweight panels, allowing for consignment on a light deliver y vehicle or even to be carried by hand in areas with limited infrastructure,” says Gwagwa.

“Despite being lightweight, the steel panels offer corrosion resistance due to the specialised coating we are renowned for introducing to the market. No heavyduty equipment is required on-site for installation, which saves municipalities on site preparation costs and results in a faster turnaround time on the project,” Gwagwa concludes.

ABOUT SBS TANKS SBS Tanks is a leading provider of innovative water storage and security solutions. Established 25+ years ago, the company has offices in Southern Africa, East and West Africa, the USA and an extensive dealer and distributor network in the USA, Malaysia, Myanmar, Africa and Mauritius and is actively seeking new territories globally.

The SBS Tanks’ global footprint enables the company to deliver solutions that have been engineered, designed, and developed to harness and secure natural resources anywhere in the world. SBS Tanks’ products and systems are compliant with the highest internationally recognised health and safety and quality standards – ISO 9001:2015 and ISO 45001:2018.

As part of the SBS Group, SBS Tanks is focused on delivering effective, custom-designed offerings employing professionals who design and deliver technologically advanced solutions, have an in-depth understanding of the compliance requirements, international logistics and challenges faced.

SBS is proud to collaborate with global impact investment par tners the Wellspring Group.

Get in touch with SBS Tanks to find out more about their bulk, wastewater, potable, process or fire water storage tanks. Tel: 086 048 2657 Email: info@sbstanks.co.za or visit www.thesbsgroup.com.

IMIESA October 2023

35

WATER & WASTEWATER

Located at the highest point in Ntshongweni, the recently constructed 6 Mℓ Shongweni reser voir now supplies the existing Shongweni Low Level and High Level zone, as well as the Zwelibomvu, Ofudu, Clifton and Salem reser voirs downstream within this rural region of eThekwini.

New Shongweni reservoir creates additional capacity and community opportunity Construction in progress on the new 6 Mℓ Shongweni Reservoir, going up alongside the existing 0,8 Mℓ facility, which was no longer able to cope with rising water demand

Environmental, Social, and Governance (ESG) principles throughout the lifecycle of each project it undertakes.

The Contractor had initially planned to create 16 employment opportunities for the local community as the baseline CPG requirement in terms of the contract value.

However, after community engagements, the method of construction for the stormwater pipeline component was altered to facilitate labour intensive construction (LIC) methods.

This initiative therefore resulted in a further 11 project related jobs and reinforces the opportunities presented by incorporating LIC upfront in construction programmes.

A

ddressing the issue of historical supply constraints, the new facility ties in with the existing 0,8 Mℓ Shongweni reservoir, and the combined storage capacity of 6,8 Mℓ from the first and now second Shongweni reservoir is currently equipped to meet future envisaged demand.

Both are reinforced concrete potable water retaining structures.

PROJECT TEAM Client: eThekwini Water & Sanitation Consulting Engineer: Naidu Consulting Contractor: Afrostructures ISD consultant: Khanyisa Projects

36 IMIESA October 2023

Designed and built for the community, and valued at around R28 million, the new Shongweni reservoir project was finalised ahead of schedule, achieving practical completion on 20th April 2023 following an intensive 18-month construction programme.

During this process, the 30% contract participation goals (CPGs) were exceeded thanks to the commitment of the Client, eThekwini Water and Sanitation, the design team led by Naidu Consulting, and Afrostructures as the main Contractor.

To optimise CPG and related implementation, a Project Steering Committee (PSC) was established to ensure complete transparency for all stakeholders, including local leadership.

Khanyisa Projects, as the ISD Consultant, played a key role in this respect, aligning with Naidu Consulting’s mandate of applying

WATER & WASTEWATER

The new reservoir measures 32 m and 42 m in length and width, respectively, and 5 m in depth, with the structure founded on bedrock

Contractor provided resources, including a 20 tonne excavator to remedy the defective crossing and provide safe passage.

Ingenuity in design

As opposed to the minimum CPG requirement for accredited training, instead of two, the project catered for 38 community members.

The latter included two experiential learning students studying civil engineering, who received stipends.

Going beyond to win hearts and minds For all infrastructure projects, the objective is socioeconomic capacitation. However, within the South African context – as underscored by the CPGs – any construction At the onset of the construction programme, the project team donated soccer gear, which included a full soccer kit, bag and ball to the Ntshongweni youth soccer team, establishing the spirit of collaborative community engagement for the remainder of the works

activity can and does have an intensified focus for communities struggling to find sustainable employment.

That makes the new Shongweni reservoir especially notable, as the project team took a willingness to respond to every opportunity to add value, above and beyond the CPG guidelines.

In April 2022, for example, KwaZulu-Natal experienced torrential rainfall resulting in uncontrolled flooding that could be considered as one of the most catastrophic natural disasters in the history of the province.

At that point, the project was approximately 57% complete and access to site was difficult due to damaged road infrastructure. Water became an even more scarce commodity due to damaged pipeline networks. Most affected were people living near watercourses.

More than 300 women and children were temporarily housed at a local community hall. Together with community leaders, the project team then visited the victims and established what essentials were desperately needed. In response, the Contractor sponsored gas cylinders for use by the community. Additionally, the project team, together with the Robin Hood foundation sponsored blankets, mattresses, clothing, and non-perishable food items.

The April floods also restricted local children from attending school within Ntshongweni as the existing low-lying bridge was damaged. To address the problem, the

Always keeping the community top of mined, from inception the project was founded on a commitment to delivering enabling infrastructure. This in turn influenced the introduction of innovative and sustainable solutions.

That included countermeasures to combat future theft and vandalism, which is a widespread issue on infrastructure installations across South Africa. For the new Shongweni reservoir, one of the design interventions adopted is the inclusion of ultrasonic inline flow meters, which are completely buried and protected by means of a culvert system, with brick walls employed to seal off both ends. These meters transmit signals electronically via a telemetry system, and flow rates can be monitored remotely.

Connecting the old and the new reservoirs Considering the constraints in top water level, the new reservoir was constructed with a lower floor level than the existing one.

The reservoir outlets for Shongweni Reservoir 1 (the original structure) and 2 were therefore designed to ensure balancing between top water levels, as the tie Through social engagement, it was discovered that a woman within Ward 7 had aspirations to build a creche facility but lacked the necessary resources. The project team immediately sought to remedy this and together with the Robin Hood foundation, sponsored bricks to complete the creche and provide the local youth much needed support

The method of construction for the pipeline component was altered to facilitate labour intensive construction methods. This initiative resulted in a further 11 project related jobs

IMIESA October 2023

37

WATER & WASTEWATER In April 2022, KwaZulu-Natal experienced torrential rainfall resulting in uncontrolled flooding, and at that point the project was approximately 57% complete. More than 300 women and children were temporarily housed at a local community hall. The Contractor sponsored gas cylinders for use by the community. Additionally, the project team, together with the Robin Hood foundation sponsored blankets, mattresses, clothing, and non-perishable food items

in positions are lower than the Shongweni Reservoir 1 (0,8 Mℓ) level. This ensured water level balancing through outlets.

Now fully commissioned, the new 6 Mℓ Shongweni reservoir is a key node in the supply network to the downstream storage units and is a critical facility to ensure that communities have potable water on demand.

Conclusions “As engineers, there’s always a sense of pride in realising the ‘output’ of a design. However, a greater sense of accomplishment comes with seeing the

‘outcome’ of a project, especially when it contributes to improving the quality of life,” says Mahendren Manicum, managing director at Naidu Consulting.

“We believe this is the case for the new Shongweni reservoir, where thanks to the proactive engagement of all stakeholders, the client and the construction team has been able to make a real difference for the community as they take pride in their new infrastructure,” Manicum concludes.

As testimony to this, the project won a Highly Commended Award in the Community-Based Project Category at the 2023 SANRAL SAICE National Awards.

CREATE A LIFETIME BOND WITH MAPEI

The completed reservoir

IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa www.imesa.org.za

INFRASTRUCTURE DEVELOPMENT • BUILDING • MAINTENANCE SERVICE DELIVERY • UTILITIES MANAGEMENT • ROADS • ENERGY

OUR READERS ARE YOUR BUYERS IMIESA, weekly newsletters, social media posts and www.imesa.org are the platforms used by your target audience for information on infrastructure development, maintenance and service delivery. Our readers are key decision-makers in the industry.

TO ADVERTISE

Joanne Lawrie c +27 (0)82 346 5338 e joanne@infraprojects.co.za TO SUBSCRIBE

e info@infraprojects.co.za

Contact us for content marketing opportunities across print and digital platforms.

IMESA imesa_za imesa

EFFICIENT AND CLEAN SOLUTIONS FOR THE COMPLETE WATER CYCLE.

Efficient and innovative: Pumps and Valves from KSB Water means life. KSB provides reliable and efficient systems for extracting and transporting water and disposing of waste water around the world. KSB helps ensure that people have access to water wherever they are.

Our team of expert engineers have years of experience delivering complex water and waste water turnkey solutions. Find out more about KSB and our efficient solutions now. www.ksb.com/en-za KSB Pumps and Valves (Pty) Ltd Tel: +27-11-876-5600 www.ksb.com/en-za Level 1 B-BBEE Supplier

PIPE SYSTEMS

THERMOPLASTIC PIPE MATERIAL CLASSIFICATION AND PIPE STIFFNESS Ever y thermoplastic polymer has a unique CRRC (Creep Rupture Regression Cur ve) which is plotted on a log-log scale. It is the “fingerprint” of the polymer. By Mike Smart, Pr Eng*

CRRC determination

mathematical extrapolation, conforming to ISO 9080 Determination of the long-term hydrostatic strength of thermoplastics materials in pipe form by extrapolation. The Design Coefficient C (Safety Factor) is determined in conformance to ISO 12162 Classification and designation – Overall service (design) coefficient. These two values are used in a simple formula to determine the Allowable Design Stress σ for the pipe: σ = MRS/C Thermoplastic polymers have improved over time and two of the most commonly used polymers, HDPE and PVC, have both had several iterations in their development: PE 63, PE 80 and PE 100 for the former and PVC-U, PVC-M and PVC-O for the latter. PVC-O itself has developed through five classifications over more than forty years.

The classification of a thermoplastic is ten times its MRS at 50 years and 20°C. For example, PE 100 has a MRS of 10 MPa at 50 years and 20°C. PVC-U, and PVC-M, has an MRS of 25 MPa at 50 years and 20°C and should therefore be called “PVC-U 250”, to be technically correct.

PVC-M is also a “Classification 250” material because its CRRC is precisely the same as “PVC-U 250”. Its increased Allowable Design Stress (σ) is because its Design Coefficient C has been reduced from 2.0 to 1.4, justified by the improved impact strength engineered by the addition of impact modifiers to the polymer to produce tough and ductile characteristics in the pipe.

The CRRC of a polymer is determined by extensive pressure testing and

Stress-Strain Curves

PVC-O pipes are well suited for bulk water supply applications

T

his point is well illustrated in Graph 1, where the abscissa is the logarithm of Time in Hours and the ordinate the logarithm of Rupture Stress in MPa. From this graph the MRS (Minimum Required Strength) of the polymer at 20° Celsius and 50 years (438 000 hours) is determined – the ISO (International Standards Organisation) design protocol for all thermoplastic pipes.

The product performance characteristics reflected in Graph 1 are for “TOM®500”,

which is the brand name of Sizabantu Piping Systems’ technology partner, Molecor, for their Classification 500 PVC-O pipe. The MRS of TOM®500 is 55 MPa at 50 years and 53,8 MPa at 100 years.

That proves the service life of their pipe is greater than 100 years because the MRS is greater than 50 MPa at 100 years.

Rupture Stress - MPa

CREEP RUPTURE REGRESSION CURVES - 20°C 100,0 y = -1,777ln(x) + 78,083 y = -1,038ln(x) + 38,485 10,0

1,0

y = -0,381ln(x) + 14,929

1

10

100

1000

10000

100000

1000000 10000000

Time - hours

GRAPH 1: CRRC TOM®500, PVC-U and PVC-M and PE 100

PVC-O TOM®500 PVC-U & M PE 100

It is important to note the difference in the Stress-Strain Curves between Sizabantu Molecor’s TOM®500 and other lower PVC-O orientation classifications where the yield point has not been eliminated. The Stress-Strain Curve of PVC-O Classification 500 exhibits a fundamental change, compared to other thermoplastics, that produces: o Modulus of Elasticity increase o Yield-point elimination

IMIESA October 2023

41

PIPE SYSTEMS

Graph 2 shows the yield-point of other lower classification thermoplastic polymers and its elimination with Sizabantu Molecor’s TOM®500 PVC-O Classification 500. It is critically important to understand that “Classification” refers to the material from which the pipe is manufactured, and “Class” (PN) refers to the pressure class of the pipe.

As the Allowable Design Stress (σ) increases, the resulting minimum wall thickness (e) of the pipe decreases.

Based on the Barlow formula:

Ring S ffness - kN/m²

Ring S ffness - kN/m²

Ring Stiffness is also STRESS-STRAIN BEHAVIOUR proportional to E-Modulus, Stress (MPa) and this increases as the 100 classification increases.

PVC-O 500 90 Graph 3 shows the 80 70 increase in Ring Stiffness 60 for PVC-O PN 16 pipes made 50 PVC-U with SANS classification 40 30 materials and made with 20 HDPE classification TOM®500 10 material. Each has an 0 Strain (%) 0 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% increased MRS and thereby an increased GRAPH 2: Thermoplastic Pipes Stress-Strain Curves E-Modulus proportional to the increase in material e = P x OD / (2σ + P) classification, that is itself proportional mean wall thickness, it will statistically to the MRS. be approximately 5% greater than the where: e = minimum wall thickness – mm For Classification 450 and 500 the minimum and the resulting stiffness P = pipe pressure class – MPa Design Coefficient (C) is changed from about 16% higher than the above values.

OD = pipe OD – mm 1.5 to 1.4. The average Ring Stiffnesses A similar situation exists with other σ = Allowable Design Stress – MPa of a PN 16 PVC-O pipe manufactured pressure classes (PN) of PVC-O pipes, The pipe’s Ring Stiffness (SR) is proportional to the wall thickness cubed: with various classification materials is where the increase in the material’s shown in Table 1.

E-Modulus, due to the increase in its SR = E x I / (DN – en)³ Ring Stiffness (SR) values are calculated MRS, due to the increase in the material based on the minimum wall thickness classification, tends to compensate for where: E = E-Modulus at any point. Because the stiffness is the reduced wall thickness and thereby I = second moment of area (B.e³ /12) a function of the mean wall thickness, maintains, or may increase the ring en = nominal wall thickness it is statistically impossible for these stiffness of the pipe.

DN = nominal diameter values to be obtained in practice and the The South African National Standard Therefore, SR increases as the wall actual stiffness is significantly greater.

SANS 16422 is applicable to all five thickness increases. However, the pipe’s With a tolerance of 15% (Grade T) on the PVC-O Classifications, and Clause 11.3 specifies that the minimum allowable SR shall not be less than 4 kN/m² to ensure RING STIFFNESSES OF PN 16 PVC-O PIPES the pipe is sufficiently stiff whilst empty, 10 SANS 400 SR kN/m² during constructing or when drained for 9 8 SANS 450 SR kN/m² whatever reason. The PVC-O pipe may 7 be subjected to imposed soil and traffic 6 SANS 500 SR kN/m² loads while empty that it must withstand 5 4 TOM 500 SR kN/m² without assistance from internal 3 pressure to resist these loads.

2 Graph 4 shows the Ring Stiffness (SR) 1 0 of TOM®500 PVC-O 500 Classification 100 200 300 400 500 600 500 pressure pipes, of various pressure Pipe OD - mm classes (PN), plotted against their respective Ring Stiffnesses (kN/m²).

GRAPH 3: Increased Ring Stiffness with Increased Classification The Ring Stiffness shall not be less than 4 kN/m² for the lowest pressure class Ring S ffness PVC-O, SDR 34 and 51 of pipe.

20 The two lines representing SANS 791 15 S&D PVC-U sewer pipes “Normal Duty 51” and “Heavy Duty 34” are included to 10 PVC-O provide a benchmark for the pressure pipe SDR 51 5 stiffnesses. SANS 791 PVC-U S&D pipes SDR 34 0 are specifically engineered to withstand 5 10 15 20 25 superimposed loading from trench backfill Pressure Class - PN and traffic while operating in a partially or GRAPH 4: Ring Stiffness vs. Pressure Class (PN) completely empty condition.

42 IMIESA October 2023

TABLE 1: PN 16 Average Ring Stiffness vs. Material Classification

SANS Material Classification

400

450

500

TOM 500

Ring Stiffness Ave – kN/m²

9.31

4.86

4.15

7.18

The TOM®500 PVC-O 500 pressure pipes have a predominantly higher Ring Stiffness than the PVC-U sewer pipes. The SANS 791 S&D pipes have a Pipe Stiffness (SP) of 100 kPa and 300 kPa respectively; equivalent to a Ring Stiffness (SR) of 1,86 kN/m² and 5,59 kN/m² respectively.

The applicable standard for PVC-O, SANS 16422, is a standard that specifies all the critically important attributes of all PVC-O pipe classifications and piping systems. It ensures the products conform strictly to all the requirements, are suitable for their intended purpose and will have a service life of not less than 50 years – TOM®500 is not less than 100 years as shown in Graph 1 in the foregoing.

Conclusions As the number of different material classifications of thermoplastic piping systems increases, it is essential engineers and clients understand the differences between them, the implications these differences have on the per formance of the pipes manufactured from them, and how these differences must be engineered for in their application. *Owner of Genesis Consulting, a member of SAPPMA, and a specialist consultant for Sizabantu Piping Systems

Fabrication in progress on a DN 1000 PVC-O pipe section

REFERENCES

Gabions and River Mattresses Hexagon Wovenmesh Square Weldmesh Gabion Tool Sets Biodegradable Soil Blankets Soil Bioengineering

· SANS 16422 Pipes and joints made of oriented unplasticised poly(vinyl chloride) (PVC-O) for the conveyance of water under pressure – Specifications · A Study Assessing the Performance of PVC-O in Pressure Pipes by Catherine Michel – Shin-Etsu and, Johannes Akkerman – Wavin · Plastic Pipes for Water Supply and Sewage Disposal

by Prof. Lars-Eric Janson

011 882 5788 www.gabionbaskets.co.za

Gabion Rocks Geotextiles Sandbags Gabion Barriers Gabion Barrows

TRANSPORTATION ENGINEERING

An exampe of a road surveyed exhibiting poor skid resistance

Skid resistance vs surface texture and their safety implications According to the latest “South African Fatal Crashes in Context” publication by the Road Traffic Management Corporation dated December 2021, it was found that out of 48 330 vehicle accidents, during a period from 1 October 2017 to 30 June 2021, approximately 78% resulted in fatalities amounting to a severity rate of 1.203 deaths per crash. By Kaslyn Naidoo and Tony Lewis*

T

he same publication repor ted that from Januar y 2019 to June 2021, a total of 12 140 309 speed infringements were recorded, with light passenger motor vehicles accounting for 79.5% of these accidents. Speeding is considered a major factor. However, due to the difficulty of enforcing road regulations, it becomes necessary to introduce other interventions to compensate for the reckless behaviour of road users.

In South Africa systems such as safety barriers, road markings, street lighting, etc., are installed to improve the level of driver safety, while geometric alignments are also taken into consideration. This notwithstanding, there is a need to improve road pavement characteristics, particularly those pertaining to the surfacing layer. This can help alleviate the frequency of road accidents by complementing the use of these safety features and providing some level of safety in their absence where budget constraints exist. In this respect, including requirements for skid resistance can be regarded as having a direct influence on road safety.

Currently, the South African specification for roads and bridges [COTO] includes Polished

FIGURE 1: Polished Stone Value (PSV) Tester and British Pendulum Tester

44 IMIESA October 2023

Stone Value (PSV), and Mean Profile Depth (MPD). However, the skid resistance requirements of road surfaces in South Africa are not specified. Only recommendations are included in COTO. However, these have been extracted from the New Zealand and Australian standard specifications. From our observations, it appears that current South African specifications tend to focus on surface texture measurements as a means of indirectly assessing skid resistance, given the relatively easier availability of technology to measure surface texture.

The profiler beam method is generally used for network level surveys of surface texture, while the more physically laborious volumetric patch method is used, on a project basis, in the design of surfacing seals.

The Polished Stone Value In South Africa the Polished Stone Value (PSV) test is utilised as the primary test to select aggregates that are suitable for use in chip seal surfacing and asphalt mixtures.

This test provides a measure of the polishing resistance of an aggregate under test conditions that imitate the abrasive and polishing action of traffic.

Higher PSV values indicate aggregates which are more resistant to polishing while lower PSV values indicate aggregates prone to an increased rate of polishing. As aggregates polish, their surface texture in terms of micro and macrotexture decreases.

The PSV test is conducted in two stages – accelerated polishing followed by a friction test. The test specimens

TRANSPORTATION ENGINEERING

are prepared by embedding aggregate particles into a resin with a layer of fine sand spread over to ensure that the resin does not penetrate through to the surface. Once the resin has cured, the specimens are subjected to accelerated polishing in a device which applies simulated traffic loading and abrasive forces onto the specimen over several hours, gradually wearing the aggregates. The friction component is assessed, typically using a British Pendulum Tester (BPT).

The minimum PSV requirements for aggregates used in surfacing seals and asphalt, as specified in COTO Road & Bridge Specifications, are shown in Table 1.

The PSV test is generally used to evaluate aggregates at the preconstruction stage, to measure the intrinsic polishing properties of aggregates. However, this does not indicate aggregate performance in the case of other factors such as unusual traffic patterns, weathering, etc., that may occur over the pavement’s design life. Different geometric features of a road, such as sharp curves, also contribute to the rate at which aggregates are polished.

In addition to the polishing proper ties of aggregates, variations in aggregate characteristics can be attributed to factors such as aggregate crushing methods employed by quarries that result in different par ticle shapes. For instance gyrator y cone crushers produce par ticles with sharp edges, while impact type crushers tend to produce more rounded aggregate par ticles, attributing to different sur face texture proper ties of aggregates.

Surface texture

TABLE 1: Minimum PSVs requirements, as published in the COTO Road & Bridge Specifications

Aggregate Position in Seal Exposed aggregate Underlying aggregate Asphalt surfacings

Mean Profile Depth (MPD) and Sensor Measured Texture Depth (SMTD), as the survey vehicle travels forward.

The COTO Standard Specifications specify minimum requirements for macrotexture of different surfacing seals at initial construction stage and over a performance period of typically two years, although the Employer and/or Engineer is entitled to conduct texture checks on the surfacing at any time during this performance period. This standard specification is limited to surfacing seals and does not specify minimum MPD requirements over longer periods.

Skid resistance measurement Skid resistance or pavement friction is a result of frictional components known as adhesion and hysteresis.

Although there are other components of pavement friction (e.g. tyre rubber shear), they are insignificant when compared to the adhesion and hysterisis force components.

Adhesion results from the momentary molecular bonding between the rubber tyre and road surface, which is influenced by the microtexture of the surfacing aggregates, while hysteresis is the deformation of the rubber tyre as it comes into contact with the pavement surface, resulting in an irreversible

A 48 45

Relevant Aggregate Grade B C 49 50 47 48 ≥50

energy loss. Skid resistance, which is the outcome of this phenomenon, can be derived using test devices such as locked wheel testers, fixed and variable testers and sideway force testers.

Locked wheel testers are equipped with a test wheel that momentarily locks while the towing vehicle remains in motion at a constant speed. The rotating force on the wheel during the locked period provides an indication of skid resistance. However, locked wheel testers face challenges when testing around tight curves.

Fixed and variable slip testers typically indicate the effect of braking forces, which can be equated to the skid resistance. Fixed slip testers test at a fixed break force ratio, while variable slip testers investigate the effect of varying break force ratios.

Side force testers are less sensitive to typical changes in the road’s horizontal geometry, given the 20° testing angle of the test wheel. Attached to both sides of the side force survey vehicle, these test wheels rotate freely and account for both the longitudinal and transverse components of friction. The opposing force exerted by the road surface onto the angled test wheel (horizontal force) and the device’s weight (vertical force) exerted on the test wheel creates a Fully equipped sideway force testing device

Surface texture is the element of the road surface that contributes to a frictional force which opposes the forward motion a vehicle’s tyre. Studies have shown that skid resistance is influenced by macrotexture at higher speeds of travel, which, as mentioned previously, is a major contributor to road traffic accidents.

The Profiler Method uses laser technology in which a profiler laser beam, fitted to the front of a survey vehicle, is projected across the road’s surface and records texture measurements, such as

IMIESA October 2023

45

TRANSPORTATION ENGINEERING continuous sideway force measured as an indicator of skid resistance known as the sideway force co-efficient (SFC).

Sideway force testing devices have been developed to both British (BS) and Europe (CEN) standards. Besides measuring skid resistance, they have additional functional capabilities such as roughness (IRI), rutting and macrotexture (SMTD or MPD) measurements, which are collected simultaneously along the road surface. These devices are also equipped with a high definition Digital Imaging System (DIS). All data obtained is recorded against the longitudinal GPS coordinate position, which can be used in further post-survey investigations.

Road authorities therefore have the ability to assess several non-destructive test results, including skid resistance, to derive a holistic assessment of the road’s surface condition.

Low skid resistance has been found to be a significant contributor to road accidents, particularly in wet weather conditions where the surface’s frictional properties are reduced. Thus skid resistance testing is usually conducted under simulated wet weather conditions,

S

outh Africa’s Transport Minister Sindisiwe Chikunga says lessons learnt by many countries around the world show that South Africa can drastically reduce accidents and save lives. She made these and other observations following her participation on a global road safety panel discussion at the 27th World Road Congress. The event was held in Prague, Czech Republic, between 2nd and 6th October 2023.

South Africa has the 11th longest road network in the world and official statistics show that human behaviour accounts for between 86% and 94% of all road crashes, fatalities and injuries in the country.

Speaking during the panel discussion, Minister Chikunga said road safety was one of the most pressing challenges in South Africa and government was addressing it with multipronged policy interventions by state entities and regulators.

“South Africa developed the National Road Safety Strategy 2016-2030 based on the five pillars of the UN Decade of Action for Road Safety. The strategy champions the following global plans: road safety management, safer

with a controlled volume of water being sprayed on the road’s surface ahead of the testing wheel.

Assessing skid resistance The approach used in British, New Zealand and Australian (VicRoads) standards to manage skid resistance on road pavements adopts different surface friction requirements for different site characteristics. It should be noted that all three of these standards specify a test speed of approximately 50km/hr where the SFC is normalised to a speed of 50km/hr.

Areas of high pedestrian activity and busy adjacent land uses have stricter skid resistance requirements than roads with continuous lengths of carriageway with minimal adjacent land use activities. The “design” level represents the minimum surfacing skid resistance level of a road’s surface after construction, overlay, or reseal while the “investigatory” level represents the minimum surface friction level of an existing road surface at which a more detailed investigation of skid resistance becomes necessary.

Conclusions Now that technological advancements allow for simultaneous assessments of skid resistance and surface texture in South Africa, the ability to provide safer roads, and to target “risk” areas not identified by surface texture surveys alone, is possible. The implementation of requirements for skid resistance would advance South African road pavement engineers’ and road authorities’ a step for ward towards the common goal of providing safe and effectively maintained roads. *ARRB Systems

This is an edited version of the paper entitled, “Skid resistance vs surface texture, An Investigation from a safety perspective”, delivered at the 13th Conference on Asphalt Pavements for Southern Africa in October 2023. The full paper, including detailed pilot studies, is available from the authors.

XXVII PIARC conference puts the spotlight on safety roads and mobility, safer vehicles, safer road users and post-crash response. We are now focused on reducing road crashes and we do this annually, monthly, weekly and daily,” Chikunga explains.

The panel discussion was opened by former SANRAL CEO, Nazir Alli, currently the President of the World Road Association (PIARC) and the first ever PIARC president from the African continent.

In his opening remarks, Alli acknowledged that, according to the World Health Organisation, approximately 1,3 million people die each year due to road traffic crashes.

More than half of all road traffic deaths are among vulnerable road users like pedestrians, cyclists and motorcyclists, while 93% of the world’s road deaths occur in low and middle

income countries. Sub-Saharan Africa records the highest road death toll at more than 30 fatalities for every 100 000 people.

The Czech experience In sharing some of the strides made in the Czech Republic to improve road safety, Transport Minister Martin Kupka reflected on how their country – despite having access to impressive technology – still relies on increased visible policing and making sure the rules meant to save lives are enforced. He also noted the country’s similarities with the challenges of high youth death rates experienced globally, emphasising the Czech Republic’s continued efforts to drive impactful education campaigns through all relevant government structures.

IMIESA October 2023

47

ROADS & BRIDGES

Physical structures work together with social structures

THE FORMING OF EMANSOMINI’S NEW PEDESTRIAN BRIDGE ACROSS THE MBOKODWENI RIVER Designed and project managed by eThekwini Municipality – Roads Provision – Structures, this project demonstrates how the technical problems that civil engineers must deal with are often the result of a complex history. Foremost is the need to listen first to community challenges and then invest in a design solution that works for them.

A

lthough the deck measures just 100 m in length, the bridge is more significant than its size suggests. To begin with, it crosses a major geographic division – the Mbokodweni River. Prior to 1994 this “Umbogintwini River” was the boundary between the Umlazi township and the KwaZulu “Bantustan” governed by traditional authorities. Up until 2000 the river was still the official boundary of the Durban Metro, and before this the South bank of the river was not part of the city or the municipality.

PROJECT TEAM Client: eThekwini Municipality Main contractor: Natia Construction Employers’ agent (Engineer): eThekwini Municipality – Roads Provision – Structures Design team: eThekwini Municipality – Roads Provision – Structures

48 IMIESA October 2023

Historically, Emansomini and its neighbour, kwaMakhuta, have both been cut off by river valleys that were never formally bridged. For their people to reach Durban, in the north, by road, they first had to travel south, then east, and then finally up through the coastal town of Amanzimtoti – a long, complicated journey around. This is how it has always been, and for some members of the community this is how it needed to stay.

The north abutment is in eThekwini Municipality’s Ward 86, part of the bustling, dynamic township of Umlazi.

There are schools, shopping malls, many kinds of businesses, and big, fast, busy roads. This contrasts with the south side of the river inhabited by the peaceful, semirural community of Emansomini in Ward 94. Most of the roads here are gravel and there are few vehicles. The properties are big; there are many traditional rondavels, and no schools or formal shops. It is a more traditional community, with many

older people who are careful and safetyconscious and appreciate a lifestyle that is more peaceful than in the township.

The slower pace of life and more stable population also allows stronger community bonds to grow.

However, crossing the river became much more important after the construction of the large Philani Valley Shopping Mall on the northern side of the river, directly across from Emansomini. The mall functions as a transport hub, providing much cheaper fares into Durban than the old southern route through Amanzimtoti. Plus, the mall provides far more direct access to shopping.

ROADS & BRIDGES

The project commenced in January 2022 and was completed in June 2023 approximately a week ahead of schedule and within budget at a construction value of around R9,3 million

Mbokodweni Pedestrian Bridge was the Winner of the Community-Based Project Category at the SANRAL SAICE National Awards 2023

Emansomini’s new pedestrian bridge is the pride of the community

Initially, community members worked together to pay for materials, and then construct and maintain a simple footbridge across the river to the mall.

They still talk about their original bridge with immense pride and refer to the reinforced concrete structure that has now replaced it as an upgrade.

However, the original footbridge was not big enough to cope when the water level rose after heavy rains. Children could not go to school, and residents describe occasions when people tried to get expensive purchases across the river but had them swept away by the water. In December 2013, a mother and daughter were themselves carried down the river.

So, the community approached the local counsellor to propose the construction of a larger bridge. Technical staff assigned to the task assumed that a road bridge was required, and a feasibility study was conducted to investigate the details. But when the community was consulted about where the new road should go, some had a more fundamental concern: they did not want a new road bridge at all; they wanted a pedestrian route.

Cars and vehicles, it was said, would bring crime and danger from the township across the river. Furthermore, a road bridge wouldn’t bring any direct benefits for many in the community since they do not have their own cars. Either way they would still be walking across the river to get the best prices for transport at the Philani Valley Shopping Mall.

There was no clear way forward, and the project became stalled. But city officials continued to engage with the community through a sequence of additional outreach processes, and events facilitated by politicians. With the community seemly united against the road bridge, the way out of the impasse was to build a pedestrian bridge instead.

Working together across the divide to achieve real, local participation There were two major community issues to be resolved during implementation of the project. The first was that the project involved two communities who did not agree on how the benefits of the construction process should be distributed. The second was how to ensure that as much of the spending on materials and subcontractors was kept within the two immediately adjacent communities. The project team made use of a new Project Steering Committee system that was remarkably effective in resolving all issues, and it completely eliminated typical work stoppages.

After much debate, an equal number of local labourers were selected by the councillors from each ward, with the community overseeing the process. The selection was based on which unemployed members of the community had the most people in their household who they had a responsibility to provide for. As a result, many of the people involved in building the bridge have children who now use it every day to get to school.

Creating a flood resilient structure The eThekwini engineering design team observed that the most common problem with pedestrian bridge decks during recent major KwaZulu-Natal flood events was for the decks to be swept off their supporting piers. For this reason, they decided on a semi-integral support arrangement, with all piers having a rigid, monolithic connection to the bridge deck, making it impossible for the deck to be separated from its supports.

Furthermore, because all parts of the bridge deck and piers function as a single unit, the entire structure shares the work of resisting impact forces when large trees are carried down the river and strike the bridge. The overall design principle is thus a structure that is unusually tough and highly durable, with minimal maintenance and lifecycle costs.

A design challenge arose because of the large length of the deck and the short height of some of the piers, which placed it on the limit of what is possible with an integral concrete structure. The deck is a single piece of concrete that is 100 m long, and contracts and expands significantly when the temperature changes, leading to large movements at the ends.

Because the supports are fixed, they fight against the deck’s movements.

Ideally, the outer piers needed to be much higher than they are, to make them slender and flexible enough to bend and absorb the movements of the concrete without damaging themselves.

The designers needed to create a balance between the strength of the piers and their flexibility, with advanced bridge modelling software used to analyse the bridge and understand its behaviour.

Saying no to prestressed concrete and piles On purely structural construction projects, it can be difficult to share a large percentage of the work with local businesses, as much of the subcontracting work is highly technical and specialised. It was clear this would be a particularly important concern for this project, as there was high community involvement and oversight, and a need to distribute the benefits further than usual – across two different wards.

One important way to increase the portion of the subcontracting available for

IMIESA October 2023

49

ROADS & BRIDGES Temporary props had to provide ongoing support to the first spans until the rest were complete, since the flexible concrete piers could not provide stability on their own or support unbalanced loads from partially complete spans

emerging community contractors was to eliminate the portion of subcontracting that can only be performed by highly experienced specialists – the installation of piling systems and prestressing systems.

A pedestrian bridge with spans of 30 m would typically be designed with a system of prestressing cables. Instead, clever use of thin, but deep concrete haunches at the supports provided an alternative approach to strengthening the structure that made it feasible to rely exclusively on ordinary reinforcing bars.

Reinforced concrete is a much more accessible and flexible technology that allows for more spending on emerging local contractors and local labour, and for community members to develop a range of valuable, easily transferable skills during the project.

Initial geotechnical reports recommended that piles would be necessary, and specialised percussion piles were originally specified to ensure reliable installation in the riverbed. But further investigations were performed during the course of the contract to check if the expensive piles were absolutely necessary. The results gave the designers the confidence to reduce the expenditure on piling and then completely eliminate it, replacing the piles with mass concrete on particular rock outcrops, connected with a simple system of long, grouted dowel bar anchors.

Bearings and handrails are other specialised supplier/subcontracting elements that were largely swopped out, which also reduced one of the most likely causes of future maintenance

50 IMIESA October 2023

costs. When they are used, handrails are frequently stolen or vandalised, while the periodic replacement of old bearings is a major operation involving the jacking up of the bridge deck on temporary supports.

Reducing or eliminating the use of these elements substantially reduces the longterm costs of the structure.

A special section to tie it all together A highly variable deck section is not ideal for a situation where thermal effects are a major design consideration, and it also introduces complex creep and shrinkage behaviour. But the unique concrete H-section in the Emansomini bridge deck has consistently thin slab and parapet web-beams, which ensures flexibility at every point in the structural system.

This freedom of movement reduces the knock-on effects of restrained thermal expansion by allowing the whole structure to “breath”. The local flexibility also limited the effects of any problems that might occur during the concrete pour, such as delays and cold joints, which are more likely if inexperienced community

members are involved. The bridge could be poured in many small portions, and the construction programme easily modified to suit factors such as weather conditions and plant availability.

The H-section of the deck allows for a portion of the main beams to sit below the level of the walkway and a portion of the beam above the walkway. Having part of the web beams serve as parapets is a much stronger and more durable solution than concrete handrails, which are often damaged by floods or vandalism.

There were three major floods during construction, including the infamously deadly April 2022 KZN floods. But the team was still able to successfully complete the project within budget and time constraints in June 2023, despite repeated incidents of major damage to temporary works. This is an extraordinary achievement considering how much work had to be repeated after flooding damage.

The project also provided a new level of responsibility and huge opportunities for professional development for the two young structural engineers from eThekwini Municipality who ran the project: project manager Xolile Mkati and resident engineer Esona Nyakambi.

Mkati has a particular passion for ensuring that projects spread the benefits of the construction process as widely as possible within disadvantaged communities, while Nyakambi is more excited about the impact of the infrastructure itself.

“I’m really glad we made something that looks so good,” says Nyakambi.

“Townships need more beautiful infrastructure, it’s part of how we make them nicer places to live. People really do appreciate the details; they are so proud of this bridge here.”

CIDB Grade 1 CE sub-contractors from each of the two wards were appointed to complete an equal amount of the gabion work, walkway approaches and steel fixing. All materials came from local suppliers

VEHICLES & EQUIPMENT

GQEBERHA PLANT HIRE SPECIALIST

ADDS SIX NEW JCB BACKHOES

When Pieter Rademeyer does things, it’s never by half measures, and the year 1976 was a huge one for this former looseforward who played Currie Cup rugby for Eastern Province.

I

n that tumultuous year after qualifying as a plumber, he started his own business and topped it all by marrying his high school sweetheart, Betsie, who was a teacher at that time before joining the business and is still at his side.

“Soon after qualifying as a plumber in Port Elizabeth (now Gqeberha), I realised there were real opportunities for larger volume plumbing work in the housing and townhouse construction markets,” recalls Rademeyer.

“I landed my first big project of 1 800 toilet structures, which was followed up by another large one. This was the beginning of the plant hire business as there was a shortage of machines for hire and we decided to buy our first machine. The urge to enter the construction world had also taken hold of me and I started planning to do that next.”

The townhouse boom of the 1980s was in full swing and Rademeyer initially built a small complex of seven units and named it Pieter Park after his one son, Pieter.

The next complex was 60 units, which he named Karilze after his two daughters, Karien and Ilze. The following 60 units were called Jabeth, named after his other son, Jaco, and his wife, Betsie. Thereafter 30 units were built on an old nursery he had bought and were named Radé after the family name.

“We had now grown to develop and build a retail centre on the site where I had grown up and soon embarked on developing and building warehouses and office space that we rent out. I found my niche when we embarked on developing Bell Equipment Gqeberha branch manager, Gert Nelson (left) with Pieter Rademeyer, managing director of the Pieter Rademeyer Group

One of Pieter Rademeyer Plant Hire’s six new JCB 3CX Global backhoe loaders, which were bought with extended warranties to 36 months or 6 000 hours

and building ‘ life rights’ retirement villages. We are presently busy with our fourth retirement village.”

Divisional expansion By the 2000s, the Pieter Rademeyer Group as a brand name was firmly established and had evolved into four divisions namely: Pieter Rademeyer Plumbers, Pieter Rademeyer Developers, Pieter Rademeyer Ensure, and Pieter Rademeyer Plant Hire.

The Plant Hire division experienced a watershed year in 2014 when it changed its chosen brand of backhoe loader, buying 14 JCB 3CX Eco machines.

“I had been convinced to try out the JCB 3CX backhoe loaders and our plant manager, Gerrie du Preez, was very impressed with the durable design and build of these machines that proved their mettle to both our construction teams on internal plant hire and the broader public on conventional plant hire,” says Rademeyer.

Of the 14 bought in 2014, only two have remained, with the balance having been sold out of hand as they are highly sought after on the preowned market.

“We were very pleased to hear that a strong South African company like Bell

Equipment had been appointed as the local distributor for the JCB brand and in March 2023 we contacted Tom Swartz, the Bell Equipment sales representative, to talk about replacement machines for our fleet,” Rademeyer continues.

“Bell Equipment’s special offer through a local bank (ABSA JCB Finance) was also enticing.”

Extended warranties Six JCB 3CX Global backhoe loaders were delivered in April 2023 and Rademeyer expands on the deal saying that all six machines were bought with extended warranties to 36 months or 6 000 hours on the wet drivetrain due mainly to the fact that the machines are trammed between sites. Two of the JCB 3CX Global backhoe loaders have forks attached and two others have been piped for attaching hydraulic hammers on their booms should that be required.

“We receive great service from Gert Nelson and his team of mechanics and those in the parts division at Bell Equipment in Gqeberha. Their response times are good, and parts availability is never a problem,” Rademeyer concludes.

Bell Equipment has undertaken to rebrand some of Pieter Rademeyer Plant Hire’s vehicles to display the Bell and JCB brand names, as well as proudly display the company’s advertising slogan of “Follow the leader in TLB hire”.

The latter should be easy to do as the Pieter Rademeyer Group certainly knows how to lead in the sincerest manner.

IMIESA October 2023

51

CEMENT & CONCRETE

CONCRETE MIX DESIGNS now more important than ever The South African concrete industry should pay more attention to updating concrete mix designs to further improve both the sustainability and resilience of concrete, says Bryan Perrie, CEO of Cement & Concrete SA (CCSA).

P

errie was speaking at the recent ConPaveStruc 2023, the first National Conference on Concrete Roads and Allied Structures, held recently as a collaborative event between CCSA, the Council for Scientific and Industrial Research, the South African Road Federation, and the South African National Roads Agency.

The event was seen by more than 900 delegates online, with another 120 attending in person in Pietermaritzburg.

The 25 presentations at ConPaveStruc 2023 – focusing on the themes of Chemistry for Cement and Concrete, Pavements, Structures, Tunnels and Barriers – highlighted developments in cementitious materials, showcased current projects in South Africa, and presented international case studies and insights.

Perrie says that concrete is the most sustainable, resilient choice for both pavements and structures, but concrete designs should incorporate latest techniques, materials, and test methods.

“There are numerous ways to decrease embodied and long-term environmental impacts and it has become essential to take full consideration of concrete mix designs to further improve both sustainability and resilience while minimising carbon emissions,” he explains.

To achieve this: • Designs should optimise material usage • Reduce CO2 emissions • Ensure optimised aggregate grading and therefore cement content, and • Use appropriate test methods.

“When it comes to optimising designs to minimise material usage, the onus is on designers to look carefully at their designs, using the most up to date design tool methods and that the best and most suitable materials are incorporated. The cheapest materials often result in more expensive concrete,” Perrie explains.

“Gradings should also be optimised to ensure maximum packing and minimum paste content, and designers should consider the benefits of extended cements, placeability, and consider and assess early age shrinkage and cracking.”

CCSA Partners have committed to Net Zero Carbon by 2050 and local cement standards now allow a wide range of cements that should be considered by mix designers. New aggregate specifications should also be considered.

Sustainability and resilience At ConPaveStruc 2023, Perrie again emphasised the immense importance of concrete structures and concrete roads’ resilience during severe

Bryan Perrie, CEO of Cement & Concrete SA (CCSA)

climate change. As he points out, this should be a particularly strong factor to consider by decision-makers together with lifecycle cost assessment and lifecycle analysis for South African infrastructural developments.

“Sustainability is important and deals with known events that can be quantified. Resilience, on the other hand, is the ability to anticipate, prepare for, and adapt to changing conditions and withstand, respond to, and recover rapidly after a disruptive event,” adds Perrie.

“Resilient systems limit the impact of relatively unexpected adverse effects such as storms, floods and droughts, such as experienced recently in KwaZulu-Natal and the Eastern and Western Cape. The challenge is how to build more durable concrete structures and pavements, while minimising the carbon emissions generated in producing and supplying cement and concrete,” Perrie concludes. www.cemcon-sa.org.za

In a changing global climate where extreme weather events are now becoming increasingly frequent, with far higher intensity than in the past, it is impossible to have sustainable infrastructure without resilience

52 IMIESA October 2023

CEMENT & CONCRETE

The OVK Group, a leading agricultural company headquar tered in Ladybrand, South Africa, has showcased its commitment to progress with the completion of a significant warehouse refurbishment project in Gqeberha, Eastern Cape.

Refurbishment works in progress at OVK Group’s warehouse in Gqeberha

Column refurbishment for Gqeberha warehouse A key solution in the restoration was the application of Sika MonoTop®-1010 ZA, a bonding primer and reinforcement corrosion protection cement-based slurry

in the restoration was the application of Sika MonoTop®-1010 ZA, a bonding primer and reinforcement corrosion protection cement-based slurry.

Sika’s MonoTop®-1010 ZA was used as an anti-corrosion agent on the steel surfaces. This product showcased its effectiveness in preventing corrosion and enhancing the structural integrity of the columns. The Sika MonoTop®-1010 ZA was brush applied through two coats, with provision for drying overnight.

Spalling repairs

E

xecuted by a collaborative team of experts, the rejuvenation project tackled the challenge of moisture ingress affecting the structural columns.

The issue of serious spalling demanded swift intervention, which was expertly provided by Altrama, the engineering team responsible for the project. Geotech SA, the main contractor, lent their expertise to ensure the project’s seamless execution.

A meticulous process was involved.

Initially, mechanical breakers were employed to remove damaged concrete, followed by comprehensive surface preparation to eradicate corrosion from the steel components. A key solution The rejuvenation project tackled the challenge of moisture ingress affecting the structural columns. The issue of serious spalling demanded swift intervention

To address the spalling, Sika MonoTop®412NFG was trowel-applied onto the concrete surfaces after the third application of wet Sika Monotop®-1010 ZA, acting now as a bonding agent, effectively executing the patch repairs.

Sika MonoTop®-412 NFG is an R4 repair mortar with corrosion inhibitors ideal for this purpose.

The comprehensive protection solution also encompassed the application of Sika® FerroGard®-903 Plus, an active corrosion inhibitor for reinforced concrete, which was sprayed onto the entire column surface. This step

extends the lifespan of the concrete while bolstering its durability.

In addition, a layer of SikaTop® Seal107 ZA – a liquid applied, cementitious waterproofing slurry – was added to the steel components, augmenting the effective cover to the reinforcing elements. This comprehensive approach not only fortifies the structural elements, but also exemplifies OVK’s dedication to quality and longevity.

The success of this refurbishment endeavor highlights OVK’s prudent decision making. Opting for a refurbishment solution not only saved considerable time and resources compared to a complete rebuild, but also minimised operational disruptions.

This achievement is a testament to the meticulous planning and exceptional workmanship exhibited by Geotech SA, coupled with the seamless workability of Sika products.

IMIESA October 2023

53

IMESA

IMESA AFFILIATE MEMBERS PROFESSIONAL AFFILIATES

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 ERWAT mail@erwat.co.za ESCONGWENI BPH ENGINEERS (PTY) LTD info@escbph.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 Hydro-comp Enterprises info@edams.co.za Infrachamps Consulting info@infrachamps.co.za INFRATEC info@infratec.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 KSB Pumps and Valves (Pty) Ltd salesza@ksb.com KUREMA Engineering (Pty) Ltd info@kurema.co.za Lektratek Water general@lwt.co.za Loshini Projects muzi@loshini.co.za 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 Prociv Consulting & Projects Management amarunga@prociv.co.za Rainbow Reservoirs quin@rainbowres.com Re-Solve Consulting (Pty) Ltd maura@re-solve.co.za Ribicon Consulting Group (Pty) Ltd info@ribicon.co.za Royal HaskoningDHV francisg@rhdv.com SABITA info@sabita.co.za SAFRIPOL mberry@safripol.com SAGI annette@sagi.co.za SALGA info@salga.org.za 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 Siroccon International (Pty) Ltd admin@siroccon.co.za 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 SMEC capetown@smec.com SOUTH AFRICAN VALUE EDUCATION Sabiha@savegroup.co.za Southern African Society for Trenchless Technology director@sasst.org.za SRK Consulting jomar@srk.co.za Star Of Life Emergency Trading CC admin@staroflife.co.za TPA Consulting roger@tpa.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

SEAMLESS PRODUCTION SUPPORTS AGGREGATE TARGETS ON N3 REVAMP One of the South African government’s 62 Strategic Integrated Projects gazetted as part of the Infrastructure Investment Plan approved by Cabinet in 2020, the N3 national road upgrade – which focuses on an 80 km section from Durban to Pietermaritzburg – continues apace.

L

ocated right at the doorstep of the very first package of the project – the 6 km stretch between the Dardanelles Interchange and the Lynnfield Park Interchange – AfriSam’s Umlaas Road Quarry is playing a key role in keeping this vital national project ticking.

The magnitude has placed severe pressure on local construction material suppliers in the area. To provide context, the project has required 300 000 tonnes of fill material per month for the past two years.

From the onset, the team at AfriSam’s Umlaas operation has always focused its efforts on the “blue” material, with AfriSam’s Pietermaritzburg Quarry, located some 30 km away, providing the necessary backup with the supply of sub-base material, including G2, G4 and G6.

“Due to the sheer scale of the project, we had to more than double our pre-Covid volumes in 2021, maintaining the same feat in 2022,” says Theolan Govender, regional manager overseeing the AfriSam Umlaas Road Quarry. “A key talking point is our ability to push these massive volumes using the existing resources, thus transforming this small quarry into a big operation using a very lean team.”

Mobile crushing and screening To achieve this feat, AfriSam mobilised two existing trains of mobile crushers and screens (comprising eight machines in total) to complement the static plant.

To maintain high plant availability on the old mobile trains, AfriSam has deployed a maintenance specialist who is well versed with mobile solutions. The stringent maintenance regime has already paid dividends; the team has managed to double the mobile plant’s availability, running at a 55% overall equipment effectiveness, which is quite extraordinary for these 20 year old units.

“Effective management of resources has been key to keeping up with the massive aggregates demand. The lean team at AfriSam’s Umlaas Road Quarry has demonstrated its ability to do more with less. This has been done safely and cost-effectively, which speaks directly to the team’s competence and commitment to the cause,” concludes Govender.

AfriSam’s Umlaas Road Quarry is playing a key role in supplying the N3 national road upgrade project

IMIESA October 2023

55

CEMENT & CONCRETE

NOMINATIONS NOW OPEN FOR CCSA’S 2024 FULTON AWARDS Cement & Concrete SA (CCSA) is now calling for nominations for the prestigious 2024 Fulton Awards, the South African construction, civil engineering and architectural industries’ premier accolades for excellence in concrete. The deadline for full submissions is 15th December 2023.

H

Infrastructure of over R100 m: The 2022 Fulton Awards winner was the Ashton Arch in Ashton, Western Cape, entered by design consultants, AECOM S.A.

anlie Turner, business development manager of CCSA, says the Fulton Awards were initiated in 1979 as a tribute to the late Dr Sandy Fulton, former director of the Portland Cement Institute, for his outstanding contributions to the understanding, development and improvement of concrete, which are recognised internationally.

“The 2024 Awards continue the biennial Fulton Awards’ legacy and the recognition they bestow on projects displaying excellence in concrete. The Awards – given to the entire team responsible for producing the structure, or creating the development, including the owner/ developer and all associated professionals – can be likened to the ‘ Oscars’ of the construction industry,” Turner states.

She says past Fulton Awards were won by local projects that from design, innovation and execution parameters are world-class structures, and worthy of competing with the

Infrastructure of under R100 m: The winner in this category in the 2022 Fulton Awards was the modification of the Umhlatuzana River Bridge in Durban, entered by the eThekwini Municipality Roads Provision Department’s Structures Branch

best around the globe. “As an international partner of the American Concrete Institute (ACI), CCSA will nominate Fulton Award winners for the ACI’s Excellence in Concrete Construction Awards 2024, in line with the American awards’ project categories, and eligibility criteria. Success in this major competition will add invaluable international acclaim to any project team,” she explains.

The categories for the 2024 Fulton Awards are: • Buildings of up to R50 m in value: Use of concrete as the principal construction material, demonstrating an exceptional structure, design principles, construction techniques, surface finishes or particular detail in an aesthetic manner. Office buildings, residential, schools, commercial, factories, warehousing, and industrial structures fall in this category.

• Buildings of over R50 m in value: As above, but of greater project value.

• Infrastructure of up to R100 m in value: Use of concrete as the principal construction material, demonstrating an exceptional structure, design principles, construction techniques, surface finishes or particular

detail in an aesthetic manner, such as in bridges, roads, water resources, marine structures, power, and transportation.

• Infrastructure of over R100 m in value: As above, but of greater project value.

• Innovation and invention in concrete: This category includes research, technologies, new applications, techniques, designs and/ or concepts which have been developed and utilised for a project.

The adjudication panel for the 2024 awards will be Bryan Perrie, CEO of CCSA; Stephen Humphries, director of Nyeleti Consulting; and Daniel van der Merwe of LEAF Architects, who will once again visit all the entered projects in person to ensure that the entries are not merely judged on written submissions, but on the actual projects’ merits.

For more information and nomination forms, visit https://www.cemcon-sa.org. za/2024-fulton-awards or consult CCSA membership and events manager, Natasja Pols, on email natasja.pols@cemcon-sa.org.za

INDEX TO ADVERTISERS AfriSam AKS Lining Systems EnviroServ Gabion Baskets IMESA

56 IMIESA October 2023

6, OFC 46 27 43 2, 54, IBC

JPCE KSB Pumps and Valves Magalies Water Mapei M & C Consulting Engineers

33 40 12 38 23

Rand Water SBS Tanks Seaprow SA Telkom Business SMB uMngeni-uThukela Water

29 OBC 4 14, 24 IFC

CALL FOR

abstracts TH 87IMESA

IMESA

CONFERENCE

Engineering Revolutionised

06 - 08 November 2024 CAPE TOWN | GRANDWEST

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)