IMIESA January 2021

www.infrastructurenews.co.za

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

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE

Dams & Reservoirs Automatic control valves regulate the levels

Environmental Engineering Gabion river protection

Capital Equipment & Plant Hire

IN THE HOT SEAT

The right equipment, the best support

We recognise the vital importance of providing a basket of products to our customers, irrespective of their size, or the scale of the project. This, combined with our expert technical support, makes the difference.” Dave Miles Head: Materials Business Unit, PPC 8 l uVo ) ) I S S N 0I S2S5N7 01295778 1 9 V7 o m leu m 4 5e N4o6 . N0o9. •0 1 S•e pJtaenmu ba er yr 2 0 2 10 •• R 5R55.50.00 0( i n( icnl .c lVAT . VAT

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INSIDE

VOLUME 46 NO. 01 JANUARY 2021

www.infrastructurenews.co.za

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www.infrastructurenews.co.za

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

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE

Regulars

Waste Management

Editor’s comment

3

President’s comment

5

Index to advertisers

52

Institute News Dams & Reservoirs Automatic control valves regulate the levels

Environmental Engineering

Meet IMESA’s 2021 branch representatives

6

Gabion river protection

Capital Equipment & Plant Hire The right equipment, the best support

IN THE HOT SEAT

We recognise the vital importance of providing a basket of products to our customers, irrespective of their size, or the scale of the project. This, combined with our expert technical support, makes the difference.” Dave Miles Head: Materials Business Unit, PPC 8 l uVo ) ) I S S N 0I S2S5N7 01295778 1 9 V7 o m leu m 4 5e N4o6 . N0o9. •0 1 S•e pJtaenmu ba er yr 2 0 2 10 •• R 5R55.50.00 0( i n( icnl .c lVAT . VAT

ON THE COVER One of the founding members of the International Organization for Standardization, the South African Bureau of Standards (SABS) has a proud history of innovation and partnership with industry. IMIESA speaks to Dr Sadhvir Bissoon, executive: Standards at the SABS, and senior team members on electrotechnical developments.

12

Making infrastructure development a reality

8

Cover Story Setting the benchmark for electrical excellence and safety

10

Dams & Reservoirs Behind the scenes of the Kashimbila Multipurpose Dam

12

Automatic control valves regulate the levels

14

Water & Wastewater

P10

IN THE HOT SEAT

Upgrading the Midmar WTP

DAMS & RESERVOIRS Behind the scenes of the Kashimbila Multipurpose Dam

28

4IR in the waste sector

29

The importance of postclosure management

30

Capital Equipment & Plant Hire Why you should hire from CHPA members 32

Financing

Wastewater is also a source

PPC has been in business for close on 129 years and has become a household brand in South Africa. IMIESA talks to Dave Miles, head: Materials Business Unit, PPC, about market gains and growth strategies in this multifaceted segment. P26

Tshwane ready to up its waste game

16

Understanding your water consumption 18

Planers at the cutting edge

33

The right equipment, the best support

34

Built to perform

36

Reinventing modular energy storage

36

Built to keep on performing

37

The road ahead with Ammann

38

Bell beefs up excavator range

41

City of Cape Town Constructing for and with the community

42

Innovative use of builders’ rubble

44

Towards a water secure future

45

19

Construction Law Environmental Engineering Flexible and permeable river protection 22

Meeting demand for high grade bitumen 24 25

Hot Seat Creating new possibilities

25

BITUMEN & ASPHALT NME innovations for Africa

46

Bitumen & Asphalt NME innovations for Africa

Covid-19: Rethinking public sector tenders and contracts

26

Cement & Concrete Minor concrete defects and their remedies

48

Experts in bespoke culverts

51

Building precast wind towers that last

52

42

CITY OF CAPE TOWN Constructing for and with the community

THE FLOW MUST GO ON.

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EDITOR’S COMMENT

Work the problems and find solutions

MANAGING EDITOR Alastair Currie JOURNALIST Nombulelo Manyana HEAD OF DESIGN Beren Bauermeister CHIEF SUB-EDITOR Tristan Snijders CONTRIBUTORS Bhavna Soni, Chuene Ramphele, Natalie Reyneke, Peter Townshend PRODUCTION & CLIENT LIAISON MANAGER Antois-Leigh Nepgen PRODUCTION COORDINATOR Jacqueline Modise GROUP SALES MANAGER Chilomia Van Wijk BOOKKEEPER Tonya Hebenton DISTRIBUTION MANAGER Nomsa Masina DISTRIBUTION COORDINATOR Asha Pursotham SUBSCRIPTIONS subs@3smedia.co.za PRINTERS Novus Print Montague Gardens ___________________________________________________

D

espite our best hopes, the war against the novel coronavirus continues into 2021, deepening the economic crisis, both locally and internationally; however, there is light at the end of the tunnel. At home, a sustained inflow of local and international funds into JSE stocks underscores this, even though leading ratings agencies continue to downgrade South Africa.

The third Investment South Africa Conference, held in November 2020, was a further indication of bullish sentiment, yielding an investment commitment of R109.6 billion. Added to the investments raised for the first and second conference, this brings the total pipeline to around R773.6 billion. This clearly indicates the faith and willingness of the private sector to help rebuild South Africa.

South Africa’s roads industry will also welcome the recent news that the New Development Bank (NDB) has approved a project loan of up to US$1 billion for the South Africa National Nontoll Roads Management Programme, aimed at improving local transport infrastructure. The NDB is a dedicated financial institution serving the BRICS member states, namely Brazil, Russia, India, China and South Africa.

ADVERTISING SALES KEY ACCOUNT MANAGER Joanne Lawrie Tel: +27 (0)11 233 2600 / +27 (0)82 346 5338 Email: joanne@3smedia.co.za ___________________________________________________

PUBLISHER Jacques Breytenbach 3S Media 46 Milkyway Avenue, Frankenwald, 2090 PO Box 92026, Norwood 2117 Tel: +27 (0)11 233 2600 www.3smedia.co.za ANNUAL SUBSCRIPTION: R600.00 (INCL VAT) ISSN 0257 1978 IMIESA, Inst.MUNIC. ENG. S. AFR. © Copyright 2021. 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

Bringing everyone on board

KWAZULU-NATAL Secretary: Ingrid Botton Tel: +27 (0)31 266 3263 Email: imesakzn@imesa.org.za

In any country, the enabling framework rests with government, in partnership with business and civil society. Given South Africa’s high unemployment, that means collective buy-in is vital in ensuring that capital projects are well planned and executed.

It’s frustrating that the implementation of ‘shovel-ready’ infrastructure projects remains elusive; however, I’m confident that 2021 will see tangible progress, particularly in key areas like ICT, housing, roads, water, sanitation and renewable energy – if the public and private sector can agree on the common goals.

NORTHERN PROVINCES Secretary: Ollah Mthembu Tel: +27 (0)82 823 7104 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 7114 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 either in whole or in part 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. _____________________________________________

Public debt and municipal performance As we rebuild, though, it’s vital that fiscal discipline be maintained. In this respect, reining in public sector debt in non-essential areas is a key priority. Another is the urgent need to address the poor state of many of our municipalities. Top performing municipalities are socio-economic enablers. That’s why it’s especially important that the 2021 Municipal Elections go ahead as planned. A successful outcome will serve as a catalyst for positive local government realignment and structuring. It will also help to ensure that the right people are in place to deliver services.

Across the board, however, the most important priority for 2021 is the local and international vaccine roll-out.

Widespread vaccination is vital to South African and global recovery.

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.

@infrastructure4 www.infrastruct

urenews.co.za

Infrastructure News

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

INFRASTRUCTURE

DEVELOPMENT •

SERVICE DELIVERY

• ROADS • BUILDING

Cover opportunity

• MAINTENANCE

Novus Holdings is a Level 2 Broad-Based Black Economic Empowerment (BBBEE) Contributor, with 125% recognised procurement recognition. View our BBBEE scorecard here: https://novus.holdings/sustainability/transformation Dams & Reservo irs

The ABC logo is a valued stamp of measurement and trust, providing accurate and comparable circulation figures that protect the way advertising is traded.

IMIESA is ABC audited and certified.

Effective two-way communication is essential, which has been a key motivating factor for the launch of Construction Alliance South Africa (CASA) in January 2021. CASA is represented by 29 of the sector’s professional, contractor, supplier and other bodies.

John Matthews, chairperson, CASA, said the need for unity in the sector cannot be overemphasised.

Adding to this viewpoint, Gregory Mofokeng from the Black Business Council in the Built Environment and CASA deputy chairperson, said it was important for the industry to forge a united front to demonstrate a serious commitment to collectively respond to industry issues.

valves Automatic control regulate the levels

Environmental Engineering

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.

Gabion river protection

Capital Equipment & Plant Hiret,

The right equipmen the best support

products IN THE HOT SEATvital importance of providing a basket ofof the

size, or the scale We recognise the irrespective of their technical support, makes to our customers, with our expert Unit, PPC project. This, combined Materials Business Dave Miles Head: the difference.”

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) ) VAT . VAT •• R 5R55.50.00 0( i n( icnl c l .

IMIESA January 2021

3

FORWARD-THINKING

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Our team of international engineers, marketing and software development specialists collaborate to provide practical, data-driven solutions that maximise road and pavement performance and minimise lifecycle cost.

We are committed to providing the best pavement testing equipment and support while continually advancing the state-of-the-art pavement technology like the introduction of our ‘intelligent Pavement Assessment Vehicle’ (iPAVe), designed for sheer efficiency, speed, and functionality.

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PRESIDENT’S COMMENT

IMESA

Ethics and

infrastructure A warm welcome to all our Institute members and IMIESA readers! We hoped that we’d see the back of Covid-19 going into 2021, but that was not to be. The best we can do for now is adhere to health and safety protocols and await the nationwide vaccination roll-out.

T

he year 2020 was period of turbulent change; however, histor y demonstrates that change is inevitable and that we must embrace both the threats and opportunities presented. This is particularly the case when it comes to addressing the major inequalities in our society exacerbated by the pandemic. Examples include infrastructure gaps in the provision of key ser vices that include housing, water and sanitation, and transportation.

For municipal engineers, the responsibility rests with us to deliver the optimum solutions if we want our communities and regional economies to flourish. Despite recent budget cuts, a lot can still be achieved when we prioritise the most urgent projects and implement a value engineering approach.

From past Auditor-General reports, we know that wasteful and fruitless expenditure has been a major factor hampering ser vice deliver y and this must stop. A contributing factor has been a fragmented approach to planning and execution, the so-called ‘fast-tracking’ methodology where projects deemed urgent are actioned, sometimes without effective due diligence.

Going for ward, rigorous project, risk management and quality control processes are essential, as is real-time oversight of infrastructure expenditure.

Code of Conduct As civil and municipal engineers, we must stand together in ensuring that we live up to the Code of Conduct for Registered Persons in terms of the Engineering Professions Act (No. 46 of 2000). In addition to this, one of my key mandates as IMESA’s 2020-22 President is to take this a step fur ther by motivating that ethics be made a compulsor y part of the CPD cycle required for registration with the Engineering Council of South Africa.

That would require registered practitioners to attend an ethics presentation annually during their five-year registration cycle.

Within my personal life, my husband and two children are qualified medical doctors and their professional lives are governed by their Hippocratic Oath. In my view, civil engineers should take a similar oath that determines the moral principles for ethical practice since their actions have a direct bearing on civilised society.

ambitious infrastructure-led economic recover y plan will ser ve as a vital catalyst.

As municipal and civil engineers, we are an integral part of that process and have an onerous responsibility to act as quality assurance gatekeepers.

Actions have consequences Our actions can either be intentional or unintentional. However, even if unintentional, a poorly evaluated decision or applied solution can still have negative consequences that could have been avoided.

In the aftermath of the devastation caused by the pandemic, South Africa’s

Bhavna Soni, president, IMESA

IMIESA January 2021

5

IMESA BRANCHES

Meet IMESA’s 2021 branch representatives To better serve its members, as well as its mentorship, training and CPD initiatives, IMESA has seven regional branches that interact with engineers, technologists and technicians within South Africa’s 278 municipalities. Eight of these are metros, with the balance comprising 44 district and 226 local municipalities. Contact the branch in your region for more information about local workshops, seminars and our annual conferences.

Ayanda Skwebu Oliver Ive

BORDER Committee Branch Chairperson: Ryan Nell Branch Secretary: Celeste Vosloo Additional members: Deon McQuirk Ayanda Skwebu Luleka Shongwe Andiswa Mzinyati Theunis Schoeman Jonathan Clarke Sandile Sojini

2021 Planning

Ryan Nell, Chairperson

If circumstances permit, the branch will continue to host seminars as well as organise technical tours of projects within the Border region. Towards the end of the year, planning will begin for the annual IMESA Conference to be held in East London in 2022.

FREE STATE / NORTHERN CAPE

IMESA

promoting membership as soon as Covid-19 restrictions are lifted and travel is safe.

NORTHERN PROVINCES Committee Branch Chairperson: Vuyani Ernest Gxagxama Vicechairperson: Khomotso Mdhuli Branch Secretary: Ollah Mthembu Secretary: Odwa Badi

Vuyani Gxagxama, Chairperson

Overview IMESA’s Northern Provinces branch is the largest and represents Gauteng, Mpumalanga, Limpopo, and North West. The branch has 11 members serving as IMESA Regional Council representatives for 2020-2022.

Committee

2021 Planning

Branch Chairperson: Vacant Branch Secretary: Wilma Van Der Walt

The Northern Provinces branch aims to intensify its support to members through accredited CPD programmes. Its goal is to ensure that IMESA becomes easily accessible to as many aspiring members and young engineers, and to continue its bursary offering to qualifying candidates. The branch also aims to strengthen cooperation with other professional bodies, institutions of higher learning and government. Another imperative goal of the branch is to contribute meaningfully

Overview

Overview

The IMESA Border branch operates from East London and covers the area up to KwaZuluNatal and Free State borders. Four members from the Border branch have been elected to serve on the IMESA Council for 2020-2022: Ryan Nell Deon McQuirk

The Free State/Northern Cape branch, which covers the enormous area of two regions and like so many other organisations affected by Covid-19, has been unable to arrange member activities and was dormant for most of last year. IMESA Exco members will visit the branch in 2021 to set up a committee and assist with

Branch contact details:

BORDER EASTERN CAPE FREE STATE/N. CAPE KWAZULU-NATAL NORTHERN PROVINCES SOUTHERN CAPE/KAROO WESTERN CAPE HEAD OFFICE

Chairperson

Ryan Nel

ryann@buffalocity.gov.za

Branch Secretary

Celeste Vosloo

celestev@buffalocity.gov.za

Chairperson

Melanie Geyer

mgeyer@mandelametro.gov.za

Branch Secretary

Susan Canestra

imesaec@imesa.org.za

Chairperson

(vacant)

Branch Secretary

Wilma van der Walt

imesafsnc@imesa.org.za

Chairperson

Jogie Naidoo

jogie.naidoo@umhlathuze.gov.za

Branch Secretary

Narisha Sogan

imesakzn@imesa.org.za

Chairperson

Vuyani Gxagxama

GxagxamaV@dws.gov.za

Branch Secretary

Ollah Mthembu

np@imesa.org.za

Chairperson

Dawie Gerritts

dawiegerrits@gmail.com

Branch Secretary

Henrietta Oliver

imesasck@imesa.org.za

Chairperson

Jeanine du Preez

operations@imesa.org.za

Branch Secretary

Michelle Ackerman

imesawc@imesa.org.za

Head Office Manager

Ingrid Botton

admin@imesa.org.za

Membership

Adel Naidu

info@imesa.org.za

IMESA BRANCHES

to the compilation of Infrastructure Report Card.

the

Municipal

WESTERN CAPE Committee Branch Chairperson: Jeanine du Preez Vice-chairperson: Emmarentia Stipp Branch Secretary/ Jeanine du Preez, Chairperson Seminars & Events: Michelle Ackerman Treasurer: Christo Swart

Ad-hoc Events Team: Clyde Koen Elroy Swart Fatgie Moos Zaydam Salie Princesse Muke

Overview The IMESA Western Cape branch prides itself on providing opportunities for members to learn, network and earn CPD points at their branch meetings, seminars and technical tours. The branch has eight members serving on the IMESA Council for 2020-2022, with six holding Exco portfolios.

EASTERN CAPE Committee Branch Chairperson: Melanie Geyer Vice-chairperson: Lyle Francis Branch Secretary: Susan Canestra Additional members: Gerrie van de Merwe Zirk Buys Drikus Bester Marius van Jaarsveld Zirk Buys Victor Felton Barry Martin Joseph Tsatsire Melanie Geyer Jonathan Ellis Lyle Francis

Overview The IMESA Eastern Cape branch operates from Port Elizabeth and has been in existence since 1997.

The branch committee comprises 10 active members, five of whom are employed in the municipal environment and the remainder in the consulting engineering environment.

2021 Planning The committee plans to host four branch meetings, two CPD accredited training sessions, and a social responsibility challenge.

KWAZULU-NATAL Committee Branch Chairperson: Jogindra (Jogie) Naidoo Vice-chairperson/ Jogie Naidoo, Treasurer: Chairperson Bhavna Soni Branch Secretary: Narisha Sogan Additional members: Randeer Kasserchun Sibusiso Mjwara Balan Govender Vishal Krishandutt Geoff Tooley Madhu Moopanar Mervin Govender Sumith Kasserchun Zithulele Mazibuko Veshall Kasseepursad Nilesh Beeputh Dave Wilson Ashan Nandlal Dumisani Biyela

Overview The KwaZulu-Natal branch covers the full region from the coast to interior highlands.

Three of IMESA’s Office Bearers are KwaZuluNatal branch members, namely Bhavna Soni, 2020-2022 President; Randeer Kasserchun, immediate Past President; and Geoff Tooley,

Front row (L-R): Joseph Tsatsire, Melanie Geyer and Lyle Francis. Back row (L-R): Barry Martin, Victor Felton, Jonathan Ellis, Zirk Buys, Gerrie van de Merwe and Marius van Jaarsveld. (Missing from photo: Drikus Bester and Susan Canestra)

Vice-president: Operations. Vishal Krishandutt, who is a branch committee member and IMESA Council representative, was recently inaugurated as SAICE’s new president on the 27th November 2020.

2021 Planning The branch’s task team plans to use a portion of its funds to provide free training for members during 2021. The branch currently has 337 members.

The following branch meetings are scheduled for 2021, subject to the impact of the Covid-19 regulations: • 5 March 2021 (via MS Teams) • 25 June 2021 • 17 September 2021 • 26 November 2021.

SOUTHERN CAPE / KLEIN KAROO Committee Branch Chairperson: Dawie Gerrits Vice-chairperson: Chris Swart Secretary: Dawie Gerrits, Ceciel Burger Chairperson Administration: Henrietta Oliver Treasurer: Jannie Koegelenberg Additional members: Soli Beyi *Pieter Myburgh (IMESA Vicepresident: Technical) John Daniels (past Branch Chairperson)

Overview The Southern Cape/Klein Karoo branch region covers a wide-ranging footprint that extends from the Garden Route, with its approximately 300 km of coastline, inland to Beaufort West.

2021 Planning Branch members meet four times a year for quarterly meetings. These meetings usually consist of two or three presentations on municipal engineering topics, followed by a branch meeting and a lunch.

During August, the quarterly meeting runs over two days and includes the AGM and a seminar. Municipal officials, consultants and contractors come together to network and share their insights. *In Memoriam It is with a sad and shocked heart that IMESA is announcing the sudden passing of Pieter Myburgh in January 2021. A full obituary will be published in the February 2021 edition of IMIESA. IMIESA January 2021

7

FINANCING

Chuene Ramphele, group executive: Infrastructure Delivery Division, Development Bank of Southern Africa

The Covid-19 pandemic has reduced economic performance globally and seriously aggravated South Africa’s struggling economy. This reduction in economic performance automatically inflicts a gap in funds available for infrastructure development. It is now vital that we find solutions to deliver the maximum economic benefits from infrastructure investment.

By Chuene Ramphele

Making infrastructure development a reality

C

ountries around the globe, including South Africa, are hard at work to reconstruct and revive their economies.

The language spoken is that of economic recovery plans that are resilient to address the pandemics of poverty, unemployment and inequalities.

The recent World Development Report 2020: Trading for Development in the Age of Global Value Chains clearly ascertains that, in order to reverse the serious setback to development progress and poverty reduction, countries will need to prepare for a different economy post Covid-19 by allowing for capital, labour, skills

8

IMIESA January 2021

and innovation to move into new businesses and sectors.

There is no doubt that the South African government has developed policies to support infrastructure development in South Africa. At this point, we as the role players in the infrastructure space need to focus on harmonising resources and collaborating in support of each other to realise the noble objective of sustainable economic growth.

Towards this end, President Ramaphosa’s Economic Reconstruction and Recover Plan – aimed at helping the economy recover from Covid-19 and the resultant lockdown – has placed a strong focus on creating jobs through

aggressive infrastructure investment and mass employment programmes.

This is supported by the Infrastructure Fund (IF), which will make available R100 billion over 10 years, with R10 billion in funding in the current Medium-term Expenditure Framework.

The IF will be used as viability gap funding for large-scale infrastructure investments. The support will take different forms, including the funding of deserving infrastructure projects, blended co-funding, capital subsidies, or interest rate subsidies and guarantees.

Economic benefits of infrastructure Infrastructure development has huge potential

FINANCING

to expose opportunities for multiple socioeconomic benefits. Through infrastructure development, we can practically stimulate construction, provide communities with livelihoods, enhance the supply value chain, and implement skills training and development through on-site activities.

We should not spend time debating as to which infrastructure to focus on – there is no doubt that transport, energy, roads, water, and communication networks catalyse economic growth and affect all aspects of our day to day lives.

Challenges Interestingly, what constrains infrastructure development are not the technical and engineering issues but soft issues that present hardships to projects. Too much is at stake for investors, funders and developers if infrastructure development is constrained.

I maintain that we need to address the following stumbling blocks if we are to succeed in delivering sustainable infrastructure and unlocking economic growth:

1

Community and social facilitation We must engage community members in developing and planning projects and ensure that project charters are in place as an integral part of project governance.

Partnerships with community-based organisations must be pursued to deepen and facilitate community training on the need for their participation in the development of projects within their jurisdiction.

We also require an aggressive programme to workshop the consulting and construction fraternity on social facilitation and how to ensure effective community participation in projects. This education must be recognised in the form of CPD points.

2

Stakeholder engagement Similar to the point above, it is vital that we involve people who may be affected, directly or indirectly, by the project to achieve consensus.

We need to address the needs and expectations of the stakeholders before commencing the project and, in this regard, the

District Development Model remains an instrument we should take advantage of.

3

Developing skills and capacity Strengthening and maintaining the existing skills and knowledge of the country is required to drive its infrastructure development agenda.

We need to develop our built environment institutions, focusing on artisans, engineers and professionals throughout the execution of projects.

4

Fostering technological innovation We must leapfrog into using building information modelling (BIM) as a solution for the effective delivery of infrastructure to harnesses time and cost savings. It is becoming urgent that we adopt BIM – along with other emerging technologies – to give architects, engineers and construction professionals the tools for efficient planning, design, construction and management of buildings and infrastructure.

5

Harnessing private capital Public sector budgets across the developing world are strained, with municipalities facing revenue shortfalls. We need to develop new models for co-funding infrastructure that harness private capital to leverage government spending on infrastructure, thus achieving an optimal mix of public and private finance.

The recent Sustainable Infrastructure Development Symposium indicated a total of 276 projects with an investment value of more than R2.3 trillion. This can only be achieved through investment by the private sector.

6

Infrastructure maintenance Infrastructure development must be understood as encapsulating not just the construction of infrastructure but the operation and maintenance of that infrastructure throughout its lifespan. Investing in infrastructure maintenance offers outstanding opportunities for economic stimulation by creating jobs and realising capital expenditure.

International best practice asserts that a minimum of 8% of the infrastructure budget be allocated to maintenance. It is time that this

practice is adopted by infrastructure institutions in South Africa as we implement the National Infrastructure Maintenance Strategy approved by Cabinet in 2006.

Financing considerations The Development Bank of Southern Africa (DBSA), as a progressive development finance institution, agrees with the school of thought that infrastructure development is a key driver of economic growth and development.

To achieve this, we have identified the need to design hybrid funding solutions that deliver the economic benefits of infrastructure investment while maximising the ability to leverage private sector capital.

In South Africa, the Infrastructure Investment Committee has identified three financing methods to achieve this: debt capital markets, blended financing, and the fiscus. The IF, which is managed by the DBSA, is one of those blended financing mechanisms already being implemented.

Thus, the DBSA continues its mandate to build Africa’s prosperity through financing and implementing sustainable infrastructure. In doing so, we focus on promoting economic development and sustainable growth, human resources development, and institutional capacity building by mobilising financial and other resources from national and international private and public sectors to drive sustainable development projects and programmes in South Africa and the rest of the continent.

IMIESA January 2021

9

COVER STORY

Setting the benchmark for electrical excellence and safety

One of the founding members of the International Organization for Standardization (ISO), the South African Bureau of Standards (SABS) has a proud history of innovation and partnership with industry.

IMIESA speaks to Dr Sadhvir Bissoon, executive: Standards at the SABS, and senior team members on electrotechnical developments.

C

elebrating its 75th anniversary in 2020, the SABS is South Africa’s national standards body mandated by legislation to develop, promote and maintain South African National Standards (SANS) and provide relevant conformity assessment services that support the efficient functioning of the South African economy.

SABS conformity assessment services include certification services, testing services, consignment inspections, local content verification – as prescribed by the Department of Trade, Industry & Competition (DTIC) – advisory and training services. These are all aimed at ensuring consumer safety and that both

10

IMIESA January 2021

private and public sector entities deliver quality products and services.

“Excellence in any country depends on adherence to standards, and the testing and certification of products and services that meet them,” says Bissoon, who was recently nominated to represent the SABS on the ISO Council. In addition to his other responsibilities, Bissoon is also president of the South African National Committee of the International Electrotechnical Commission (IEC).

“A core ISO mandate is the realisation of the UN’s Sustainable Development Goals, which is also enshrined in South Africa’s National Development Plan 2030, to raise the quality of life for everyone,” says Bissoon.

Key SABS developments in the electrotechnical arena include the roll-out of SANS 10142-1 (The wiring of premises – Part 1: Low-voltage installations (Edition 3: 2020)).

Another is the launch of the SANS 164 Part Dr Sadhvir Bissoon, executive: Standards, SABS

0 to Part 6 electrical components standards, which tie in with SANS 10142-1.

SANS 164-0 to SANS 164-6 cover the specific requirements for plugs, sockets and adaptors. There’s also a proposed SANS 1648 applicable to stove plug and socket outlet connections.

In terms of SANS 164-2, it is now compulsory for all new buildings to have a socket-outlet incorporating the SANS 164-2 configuration.

In response, a new range of 16 A compact three-pin plugs and sockets now becomes the standard for the local manufacturing,

COVER STORY supplier and electrical contracting market. All future appliances should also be fitted with the new plugs.

All locally manufactured and imported electrical applications up to 220 V must be verified and approved by the National Regulator for Compulsory Specifications (NRCS) in terms of the National Regulator for Compulsory Specifications Act (No. 5 of 2008). Like the SABS, the NRCS is an extension of the DTIC.

SANS 10142-1 objectives “SANS 10142-1 was revised to align with international norms,” explains John Dlamini, chair: Technical Committee and team leader: Electrical Standards, SABS. All low-voltage electrical installations must comply with the requirements of SANS 10142-1. Here, their regulation is governed by the Occupational Health and Safety Act (No. 85 of 1993) and administered by the Chief Inspector of Occupational Health and Safety of the Department of Labour.

“It also requires that an accredited person, as defined (master installation electrician, installation electrician or electrical tester for single phase), will issue a Certificate of Compliance for an electrical installation in line with the requirements set out in SANS 10142-1,” Dlamini continues. (For further details on the updates and requirements for SANS 10142-1 and SANS 164 Part 1 to 6, visit www.sabs.co.za).

SANS 164-2 compliance Most older buildings in South Africa still employ large three-pin sockets, which lends itself to the increased use of adaptors. This creates a potential fire hazard due to short circuiting, as well potential damage or malfunctioning of appliances. SANS 164-2 (installation) now prevents this.

Published in July 2020, SANS 164-2 incorporates changes in technology covered in SANS 60884-1: Plugs and socket-outlets for household and similar purposes. SANS 608841 is an adoption of the IEC 60884-1 standard.

“Some of the sockets for the new compact three-pin will indicate whether they can accommodate a rewireable plug or not,” says Dlamini. “Warning signs will also appear on adaptors to prevent the use of multiple adaptors plugged into one another. This will avoid the risk of electricity hazards due to overloading and poor connections.”

From 2018, an earlier version of the wiring code (SANS 10142-1) already required socket outlets in electrical installations to meet SANS 164-2 at every socket outlet point.

However, until now, other configurations (such

as SANS 164-1) could also be installed on to the same outlet.

“The changes in SANS 164-0 are now generic to all the SANS 164 series of standards, namely Part 1 to Part 6,” explains Sihle Qwabe, senior manager: Electrotech Engineering, SABS, who is responsible for lower voltage and electronics.

Low-voltage switchgear In terms of other recent developments, the latest SANS 10142-1 also applies to low-voltage switchgear for testing requirements.

In October 2015, IEC standard 61439 replaced SANS 60439:2004 – the standard that applied to low-voltage switchgear and control gear assemblies. “The new standard allows for any one of the three types of design verification to indicate compliance to the standard (Verification

by Type Testing, Verification by Calculation or Measurement and Verification by Design Rules), whereas the previous standard required verification by testing without reference to all categories,” Qwabe continues.

Verification by type testing subjects the equipment to performance limits or ‘destructive testing’, functional tests and most importantly includes temperature rise tests for indoor and outdoor applications. These steps are all aimed at minimising the risk of substation fires.

SABS, through its independent, thirdparty national electrical test facility, which is accredited by the South African National Accreditation System, conducts verification by type testing on all switchgear equipment.

Renewables and energy efficiency In terms of renewable energy, the SABS has also adapted IEC standards for the local market for wind farm, gas, biomass, PV solar installations and embedded generators. In terms of the latter, SABS plans to release a new IEC adapted standard mid-2021. LED energy efficiency in lighting is a further SABS mandate.

While there’s no local LED testing facility at present, the SABS has motivated for funding – a move endorsed by the NRCS.

The next step for manufacturers and suppliers is product and/ or system certification. “Product certification (SABS Mark Scheme) requires that the product is tested against the relevant SANS, thereby meeting the requisite performance and safety requirements,” explains Lenney Naidu, manager: Electrical Certification, SABS. A SABS permit is subsequently issued to the client, which permits the client to insert the SABS mark of approval on the manufactured product. “It’s a continuous process, with two audits scheduled annually, as well as random sample selection to ensure ongoing compliance to the SABS Mark Scheme requirements.”

System certification is a process of validating that a company complies to the relevant management system standard – i.e. SANS/ ISO 9001. The SABS has also been appointed by the DTIC as the verification body for local content verification.

The SABS continues to implement processes and systems to improve turnaround times in the testing of products, as well as the issuing of SABS test reports. This is clearly a priority for local manufacturers and suppliers to ensure timely access of their products into domestic, regional and international markets.

Standards are industry-driven Standards are never developed in isolation. “The SABS governs the process of the development of national standards through international best practice principles including openness, transparency, stakeholder engagement, consensus and coherence, and our success depends on proactive and constructive engagement with a diverse representation of stakeholders via our technical committees,” adds Bissoon.

Within the electrical sector, the development of market-related national standards – supported by certification, testing and verification services – drives access to markets, competitiveness and consumer well-being.

“The SABS is committed to providing a diverse range of standardisation services aligned to the DTIC industrial priority sectors, thereby supporting the socio-economic objectives of the country,” Bissoon concludes.

Certification Setting the standard establishes the benchmark.

www.sabs.co.za

IMIESA January 2021

11

DAMS & RESERVOIRS

Behind the scenes of the Kashimbila Multipurpose Dam The construction of the Kashimbila Multipurpose Dam has had a significant positive impact for Nigeria and is one of its key showcase presidential projects. The benefits to the local community have been immense and range from job creation to potable water supply, electrification, and an improved transmission network.

Kashimbila Multipurpose Dam at full flood

T

he preliminary design of the Kashimbila Multipurpose Dam on the Katsina-Ala River in the Taraba state in Nigeria was initially focused solely on the dam’s functioning as a buffer in case the natural embankment of Lake Nyos in Cameroon failed.

Lake Nyos is a volcanic crater lake around which the ash embankment has been moving and settling. Should the embankment fail, the extreme flooding that would follow would endanger the lives of a significant portion of the people in south-eastern Nigeria. As the design process progressed through a more holistic and multipurpose approach, the capacity of the dam was increased to provide irrigation and potable water to the surrounding towns and villages, as well as for the generation of hydropower.

The Nigerian government appointed SCC (Nigeria) Ltd to design and construct the flood protection dam, which was subsequently changed to provide a multipurpose use. SCC appointed Zutari to review the concept design of the spillway proposed by the Federal Ministry of Water Resources before later appointing them to conduct the detail design of the dam.

Following discussions with the various stakeholders, Zutari proposed several optimisations to the project, which resulted in

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IMIESA January 2021

Kashimbila Multipurpose Dam during construction

a safer, more affordable, and better optimised solution for all parties. These included an increase in the capacity of the proposed 6 MW hydropower generation to 40 MW, as well as optimised routing of the transmission line to improve the electricity network and distribution in eastern Nigeria.

The full project included: • a 36 m high composite dam (clay core rockfill and concrete gravity spillway) • a 40 MW hydropower station and associated substation capable of releasing 260 m3/s (four units, each with a rated flow of 65 m3/second) • the Kashimbila substation equipped with two 30 MVA triple winding transformers to connect the four generators as well as two 15 MVA for the local rural electrification supply • a 132 m long bridge to connect the two riverbanks • outlet works for the irrigation supply, potable water supply, and river releases • 210 km long double-circuit 132 kV transmission lines with OPGW with lattice towers • 45 km long double-circuit 33 kV transmission lines with OPGW with lattice towers • 45 km of 33 kV reticulation network supplying

PROJECT TEAM Ultimate client: Nigerian Federal Ministry of Water Resources and Federal Ministry of Power Zutari’s client: SCC (Nigeria) Professional team: Zutari Main contractor: SCC (Nigeria)

multiple small towns and villages in the surrounding areas with electrical supply • two new 60 MVA 132/33 kV substations • two new 15 MVA 33/11 kV substations • rehabilitation and upgrade of the 132/33 kV Yandev substation where the new Kashimbila line interconnected to the national transmission network • development of a 2 740 ha commercial irrigation scheme comprising centre pivots and flood irrigation.

Optimising the project Zutari’s innovative, creative and out-of-the-box thinking led to several changes in the initial concept of the project. These changes resulted in a multipurpose project that better serves the people of Nigeria and the communities in the area of the project.

DAMS & RESERVOIRS From the inception of the detail design in 2012, Zutari used 3D design to improve the quality of design and presentation to the construction team and, more importantly, to integrate the various elements of the project, as well as to ensure a zero-clash approach, which facilitated the construction and minimised disruption.

Using 3D models, finite element models for analysis were also developed for various components of the project for optimisation purposes. This resulted in significant cost savings to the project, not only on the dam and hydropower structure itself but also on the transmission towers.

Notable design features The initial spillway design comprised a conventional spillway and spillway return channel in the far-left bank, which resulted in an excavation volume of more than twice the volume of material needed to construct the embankment. At the time, the designers had also not fully developed the river diversion strategy.

Understanding the hydrology was key to optimising the project. With a river flow varying from ≈25 m3/s in the dry season and peaking at ≈1 500 m3/s every year during the wet season, the construction of the embankment in the riverbed presented significant challenges.

Zutari’s approach was to eliminate the conventional spillway in the left bank and instead construct a composite dam with a concrete gravity spillway on the right bank, where the bedrock was shallow, and where it would also be possible to divert the river

through 10 culverts left open in the mass gravity section, each 5.5 m wide by 7.5 m high.

These culverts would then be closed during the dry season when the flow is lowest to commence impoundment.

In order to reduce the volume of concrete required for the 18 m high right bank training walls, which were also retaining walls, Zutari used tie-back slabs to help support the wall, together with passive anchoring in both the excavated face and vertically to connect the slab and the rock foundation. Thereafter, the backfilling could commence to reach the final platform level.

The design and construction of the foundations of the transmission towers also followed an unconventional approach, as the contractor was remunerated a lump sum for the tower foundations. Finite element analysis was used to optimise the volume of concrete, backfill and loads, mainly at the strained towers, in order to assist SCC, Zutari’s client, by optimising the concrete foundations. This required a sloping top for the tower foundation, which reduced the total volume of concrete on the foundations alone by more than 1 000 m3.

The type of turbines installed also played a key role in the project's success. Taking overall due consideration of the project, Zutari selected vertical compact axial turbines (CAT) units. This arrangement, offered by only a few suppliers worldwide, was based on the ability to pre-assemble much of the turbines in the factory, ensuring easy assembly and embedding on-site. The vertical CAT also provided easy and direct access to the runner and turbine guide vanes for inspection

Kashimbila substation

and maintenance purposes, whereas such access is impossible with conventional Kaplan turbines.

A project for the people Several challenges were experienced throughout the design and construction period but were all overcome using a teamwork approach, which resulted in the first filling of the dam in 2017, followed by the successful commissioning of the power station, transmission line and substations in February 2020.

“The solution was one that provided an inspirational story to many people of Nigeria and resulted in a project designed and constructed in accordance with international best practice, yet adapted to the local conditions,” says Bertrand Rochecouste Collet, project director, Zutari.

Nigerians can now enjoy additional power on their very strained grid, potable water and power supply to the surrounding community and can look forward to the construction of the irrigation schemes, which is soon scheduled to commence.

Power station construction viewed from upstream

DAMS & RESERVOIRS

Automatic control valves regulate the levels Amanziflow Projects’ pressure-sensitive, purpose-designed diaphragm valves (DVs) open and close intuitively to keep reser voir levels and water system flows constant.

By Peter Townshend*

T

he programme for the City of Mthatha’s bulk water conveyance master plan star ted in 2012 within the O.R. Tambo District Municipality, as well as the surrounding villages. This entails the construction of a new bulk water supply system, including rising and gravity mains, as well as reser voirs to transfer the clear water pumped out of the Thornhill and Highbur y water treatment works (WTWs).

The review, design, project management and implementation phases were awarded to GIBB consulting engineers. The implementing agent is Amatola Water.

There are 25 concrete reser voirs ranging in size from 0.5 Mℓ to 12 Mℓ in capacity positioned in rural settings, some in remote areas. Each reser voir required self-regulating inlet control valves that open to fill and close off when full. Amanziflow Projects’ locally

14

IMIESA January 2021

developed and manufactured DVs by were selected because: • They do not require any external electrical source or telemetr y to operate them.

• They will close off when the reser voir is full to prevent over flow and will open automatically as the water level drops to fill the reser voir.

• They close over a short period of time

Large 1 350 mm diameter DV as a dam outlet at Ncora Dam, Eastern Cape

to prevent water hammer surges in the pipelines.

• They are totally submerged inside the reser voir to prevent vandalism.

• They are cost-effective and are supplied in sizes from 150 mm to 400 mm, as

DAMS & RESERVOIRS

was the case for this project, but can be supplied in larger sizes up to 1 350 mm in diameter.

• They maintain the top water level in the reser voir with as little as 0.5 m of head loss across the valve.

These were fitted as upward-facing control valves for the larger reser voirs, with the inlet pipe coming up under the reser voir floor. For the smaller reser voirs, the valves are downward-facing control valves with a top entr y into the reser voir. A float valve placed at the full supply level closes the DV when the reser voir is full.

The DVs were constructed in stainless steel grade 316L and can operate in the pressure range of 0.05 bar to 6 bar. Larger pressures can be accommodated with the use of ratio-reducing valves.

WTW flow control A 900 mm diameter DV is also used at the Thornhill WTW to maintain a constant flow over a series of cascading weirs through the plant. The water level at the Mthatha Dam – the source for the incoming raw water – can fluctuate and the DV automatically regulates to maintain a constant water level and therefore a constant flow into the WTW. A DV will also be used at the Highbur y WTW, where the pressure head may be as low as 0.5 m during droughts.

Ncora Dam Also, in the same area, but for the Department of Water and Sanitation, two large outlet DVs will be fitted to the Ncora Dam on the Tsomo River to replace obsolete and dysfunctional Neyrpic control valves.

The right-hand DV is already fitted, with the other one to be installed early in 2021. The two DVs are 1 350 mm in diameter each and, under 20 m head, deliver in the order of 7 m3/sec.

The DVs will automatically control the water level in the DV chamber, which then delivers controlled flows to an irrigation scheme and a small Eskom hydropower plant. These large DVs were fabricated

by Amanziflow Projects in 3CR12 material with good corrosion protection. They are certain to provide long-term durability and efficiency.

500 NB automatic control DV for water treatment works inlets and holding dams

*Peter Townshend, Pr Eng, is a director at Amanziflow Projects.

Typical 400 NB top entry DV for reservoirs and dams

400 NB upward facing control DV

Complete installation of a 250 NB automatic control DV with float valve at the top to maintain a top water level in the reservoir

250 NB upward facing control DV

WATER & WASTEWATER

WASTEWATER IS ALSO A SOURCE • Tertiary filtration of municipal wastewater is underutilised • Can provide industrial and irrigation waters • Improves final effluent quality • Protects natural resources by filtering contamination after wastewater treatment

• Well-operated wastewater plants provide an opportunity to reuse the water • Greywater allocated for industrial use will free up more water for potable use • Disc filtration can be implemented on every site without significant civil works

WASTEWATER TREATMENT

GRAVITY FILTRATION

Primary treatment BIOLOGY

• Gravity filtration assists with floc removal • Gentle removal of solids

Secondary treatment CLARIFIER

Tertiary treatment 20-MICRON SCREENING

16

IMIESA January 2021

TANK MOUNTED INSTALLATION • Plug and play • Pre-tested • Small footprint

• Easy installation • Guaranteed filtration

WATER & WASTEWATER

QUICK AND EASY FILTERING SECTORS •R emovable sector system made entirely of AISI 316L stainless steel • Quickly removable and replaceable

IMPACTS ON THE INLET LEVEL Working principle of Continuous-Dynamic Ultrascreen® Microfilter Maximum flow rate level

Filtering disks in continuous rotation

∆H water level variation occurs inside the machine

Supply channel of water to be filtered

Hydraulic disconnection

Level of filtered water inside the machine

Advanced Water Products www.ultravsolutions.co.za | info@ultravsolutions.co.za

WATER & WASTEWATER

Understanding your water consumption Regularly reading your municipal account and water meter is vital to understanding not only how you are billed, but also your consumption and whether there are any potential water leaks on your proper ty.

L

eaking taps can amount to water losses of up to 60 litres a day, while leaking toilets can waste an average of 400 litres per day. That’s 1.8 Kℓ and 12 Kℓ, respectively, ever y month. Water leaks can be ver y costly and are a large contributor to water wastage in South Africa. Knowing how to read your water meter is the first step in determining whether you have a leak.

Your meter will normally be placed on the wall close to your front boundar y line, in a meter box. Anyone who is unable to find their water meter should contact their relevant municipality. Most water meters are volumetric and have a rolling counter (row of numbers) to indicate the amount of water used. This should be checked at the same time ever y month against your consumption histor y as well as your water bill.

If your meter reading is unusually high, it may indicate a water leak. It is good practice to regularly checks for leaks as follows: 1. Ask all members of the house/building to stop using water.

2.

After half an hour, take a reading on your water meter, making note of the red numbers.

3. W ait for another hour, ensuring that absolutely no water is being used in the house/building.

4. Take another reading.

5.

Subtract the first reading from the second reading.

6. If there is a difference between these two amounts, this indicates a leak.

It is good practice to read your meter regularly and per form leak tests to help save both water and money.

Leaks should always be addressed timeously to prevent water wastage and high water bills. It is important to always close the stopcock to the house/building or the area where the leak is to be repaired before attempting to fix a leak, however, the stopcock should only be closed when absolutely necessar y, as the change in pressure that occurs when the valve is closed or opened can cause damage to pipes and pipe brackets. If you are uncertain as to how to repair a leak, consult a certified plumber.

Understanding your water bill You may not realise that you have a household or garden leak until you receive an abnormally large water bill. It is therefore important to read your bill correctly. Your municipal bill can contain two types of

Standard volumetric water meter (domestic meter) above and an older model dial meter below

LEAK DETECTION: TURN OFF ALL TAPS. MOVEMENT INDICATES A LEAK.

METER READING: 1234 KILOLITRES PLUS 567.8 LITRES

readings for water: an estimated reading or an actual reading. An estimated reading is given where the municipality does not actually take a reading from the meter at your property but rather uses an algorithm to estimate your consumption. An actual reading is given when a physical reading has been taken from your meter.

It is impor tant to always check this reading against your meter and, where estimated readings greatly differ, aler t your municipality.

Billing is typically based on kilolitre (1 000 litres) consumption and most municipalities bill consumers using a sliding scale. This means that the more water you use, the higher the rate per kilolitre you will pay. The City of Johannesburg, for example, applies a sliding scale as shown in Table 1.

Actively practising Water Wise behaviour and reducing consumption will therefore reduce your water bill.

TABLE 1 City of Johannesburg water consumption sliding scale

18

Kilolitres per connection per month

2020/21 tariff (R/kℓ) – Price per kilolitre, excluding VAT

0 kℓ to 6 kℓ

No charge

From 6 kℓ to 10 kℓ

R18.99

From 10 kℓ to 15 kℓ

R19.82

From 15 kℓ to 20 kℓ

R27.79

From 20 kℓ to 30 kℓ

R38.40

From 30 kℓ to 40 kℓ

R42.00

From 40 kℓ to 50 kℓ

R52.99

IMIESA January 2021

FOR MORE INFORMATION ON HOW TO BECOME WATER WISE, VISIT: facebook.com/WaterWiseRSA twitter.com/water_wise www.waterwise.co.za/site/home.html

WATER & WASTEWATER

Aerial view of the Midmar WTP during the early stages of the contract

Upgrading the Midmar WTP

T

he Midmar Water Treatment Plant (WTP), located in Howick, needed to be upgraded from a design operating capacity of 250 Mℓ/day to 395 Mℓ/day on a raw water intake basis.

The project required upgrades to the chemical dosing system, an additional new super pulsator clarifier, and six new rapid gravity sand filters at the main water treatment works. Additional upgrades included a new backwash water recovery tank, two new clariflocculators and a gravity thickener at the sludge treatment works, with associated mechanical, electrical, control, and instrumentation upgrades and integration.

The professional services contract was awarded to Hatch in 2013 and construction commenced in May 2015. The scope of work conducted by Hatch was extensive and covered full multidisciplinary design.

The newly upgraded plant produces 375 Mℓ/day of potable water utilising chemical

With growing water supply demands, Umgeni Water required significant upgrades to its Midmar Water Treatment Plant to provide reliable and safe water to the surrounding communities. dosing, super pulsators and rapid gravity sand filters, with disinfection using chlorine gas.

Design considerations

The raising of Midmar Dam, which was completed several years earlier, affected the system hydraulics. In order to supply the required new quantity of raw water to the plant, the existing system hydraulics were reviewed, and it was determined that the rising main would need to be duplicated, New clariflocculators in operation at the sludge plant three of the existing pumps had to be replaced, and a fourth pump and motor with associated pipework had to be installed to provide the necessary redundancy to ensure uninterrupted raw water intake into the WTP, while mitigating the risks of the Umgeni System’s failure.

The upgrading of the WTP required the addition of several key modules to an active water treatment plant. On the surface, it may appear that adding modules of an existing, proven design should be straightforward, but there were various multidisciplinary elements that had to be integrated into the existing plant.

This work had to be carried out with minimal disruption to the production of water and brought online without affecting the environmental compliance of the plant’s discharge to the Mgeni River. The design elements were also influenced by the requirements and preferences of the client’s project office, quality assurance, operations, asset and maintenance management teams.

Requirements from the engineering disciplines included hydraulics to integrate the new elements, a second rising main pipeline from the upgraded Midmar raw water pump station and geotechnical engineering for piled foundations. Structural engineering included reinforced concrete, steel, masonry and GRP, process, chemical, mechanical, electrical, control and instrumentation.

PROFESSIONAL TEAM Client: Umgeni Water Consulting engineer: Hatch Main contractor: Icon Construction

IMIESA January 2021

19

Joint International Conference with IMESA & IAWEES

2021

(Institute of Municipal Engineering of Southern Africa & International Association of Water, Environment, Energy and Society)

IMESA

CALL FOR ABSTRACTS for paper and poster presentations

THEME

SYNERGY THROUGH ENGINEERING

CATEGORIES • Environment

• Energy

• Water and Sanitation

• Financial, Legal and Regulatory

• Transport, Roads

• Data management

and Stormwater

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

09 April 2021 (poster presentations and abstract submissions)

marketing@imesa.org.za | tel +27 031 266 3263

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

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)

IFAT-Print Advert-115x307mm-repro.pdf

1

2020/12/10

16:16

Connecting Global Competence

IFAT Africa 2021

Pulsator No. 5, showing lamellar plates

Project highlights One of the project highlights was the re-engineering of the design for the backwash plant outlet to the river to ensure an aesthetically pleasing yet functional structure. Being visible to the public from the opposite side of the river, the outlet was constructed from excavated rocks and boulders.

Numerous safety enhancements were included in the design, such as the addition of ventilation equipment to the filter gallery, as well as structural modifications around the filter syphon valves to improve working conditions for operational staff.

The addition of a second backwash water balancing tank ensures improved recovery of wash water, thereby improving the overall efficiency of the treatment system and the quality of water returned to the natural environment.

The compressed-air system that serves a variety of equipment on the plant was found to be in poor condition during construction.

Through ingenuity and swift collaborative action between Hatch and the contractor, a replacement compressed-air facility was designed, installed and commissioned into service, ensuring the uninterrupted production of potable water.

A new chlorine tanker facility reduces the need for manual handling of potentially dangerous chlorine drums and associated equipment. The emergency chlorine scrubber (ECS) design was subjected to critical design reviews to ensure that it meets the requirements of a major hazardous installation (MHI), as well as client safety requirements. The ECS is believed to be the largest of its type in South Africa.

Africa's leading trade fair for water, sewage, refuse and recycling.

July 13-15, 2021 • Johannesburg Gallagher Convention Centre, Midrand

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CM

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Project delivery Numerous subconsultants and subcontractors were required to undertake this large, multidisciplinary, brownfield project. The upgrade, completed in June 2019, is a true triumph of teamwork from the many individuals and companies that participated during the life of the project.

Increasing the capacity of the plant greatly improves Umgeni Water’s ability to provide a valuable basic resource to a wider community.

Potable water is now available to a bigger service area, thus reaching communities that previously did not have access to a reliable supply of clean water.

Don’t miss IFAT Africa 2021!

The latest trends, solutions and innovations across water, wastewater, sewage, refuse, recycling, and renewable energies. Featuring: • • • • • •

Key industry exhibitors 3 days of business connections Renewable Energy Zone – Powered by IFAT High-level Supporting Programme CPD Accredited Masterclasses delivered by industry bodies Expert Advisory Board

Presented by Messe Muenchen South Africa Co-located with:

food & drink technology Africa

www.ifat-africa.com The emergency chlorine scrubber is believed to be the largest of its type in South Africa

IMIESA January 2021

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ENVIRONMENTAL ENGINEERING

Flexible and permeable river protection The increasing incidence and severity of extreme flood events, combined with rising stormwater velocities, constantly threatens to undermine riverbank protection systems. Environmentally engineered countermeasures are an effective response, says Louis Cheyne, managing director, Gabion Baskets.

By Alastair Currie

R

iverbanks and riverbeds are typically composed of soft underlying materials, like clayey soils and black turf, that are especially prone to erosion. In addition to localised damage, this can also contribute to downstream impacts like excessive sedimentation build-up in dams.

“In developing the best river erosion system design, the goal is to work with the hydraulic forces rather than against them,” Cheyne explains. “In this respect, gabion systems provide the best approach, since they are essentially wire-framed structures filled with rocks that together enable some degree of permeability. The extent of this will be dependent on the site. For example, in mass gravity gabion retaining wall structures, erosion protection blankets are often included to minimise fines loss.”

The double-twisted hexagonal woven steel mesh used to construct gabion baskets and mattresses is designed to flex, which is important for longer-term integrity. Selecting a Class A galvanised wire specification is equally important to counter abrasion and corrosion.

Galfan and PVC In especially demanding conditions, Galfan coated wire is recommended where high

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IMIESA January 2021

Construction works in progress to repair and upgrade an existing gabion mattress system designed to protect a pedestrian bridge crossing a strongly flowing river in the DRC

levels of pollution are present. This is an increasingly common factor within urban river systems exposed to industrial waste and untreated effluent.

Galfan is composed of a higher-grade steel coated with a zinc-aluminum layer. The use of Galfan is equally recommended for fast-flowing, turbulent river courses. Here, higher levels of oxygenation occur as the rapidly flowing water swirls around gabion structures. In the case of both Class A and Galfan wire, a PVC coating can also be applied to achieve additional protection.

Typically, the woven mesh used for baskets and mattresses is 2.7 mm and 2.2 mm respectively.

However, some clients specify a 2.7 mm wire thickness for both products for added overall system durability.

“Thanks to the simplicity of gabion construction techniques, you can place or ‘float’ the baskets and mattresses directly on to the riverbed,” Cheyne continues. “This would obviously not be the case for a precast or in situ concrete structure, which will always need a reinforced foundation, ideally placed on the bedrock. As an alternative approach, we have seen concrete retaining block wall structures built on top of gabion baskets, founded on an apron mattress in the river, which then proves optimal.”

ENVIRONMENTAL ENGINEERING

Workers packing the new gabion mattress extensions. Gabion systems are well suited to labour-intensive construction techniques

Configuration and applications Gabions are well suited to river diversion structures, longitudinal protection walls, culvert in- and outlets, low-level bridge crossings, and weirs. Bridge abutments are another popular application. On smaller bridges, the abutments can be constructed entirely using gabions. And for larger bridges where the abutments are constructed in concrete, gabion baskets can be constructed around their base to form a protective layer against erosion and impacts from flotsam, especially during flood conditions.

“Mattresses are especially ideal for river channel linings and can be installed at a

Bainskloof, Western Cape: a schematic drawing for a 3m high pedestrian bridge abutment structure comprising gabion baskets founded in the river on a gabion mattress apron. The woven mesh specified was Class A galvanised with a PVC coating

Sausage gabions can be used to prevent further riverbank erosion or can form part of an original, environmentally engineered design

maximum slope of 45 degrees, as long as they’re anchored at the top,” says Cheyne.

“They also serve a vital role when used in conjunction with gabion walls to minimise the risk of scouring around the toe of the structure.

We recently supplied woven wire mesh systems for a client in the DRC where strong river currents made this a top priority.”

Potential impact is another reason why Cheyne strongly advises against using welded mesh. Another reason is that welded mesh, which is primarily designed for architectural and building cladding applications, is designed to be rigid. It won’t flex, which – in a river course – will usually result in premature failure. In contrast, woven mesh gabions can move, settle and bend without compromising the overall, environmentally engineered design. Woven mesh also has a much higher tensile strength.

“The hydraulic forces generated by rivers should never be underestimated. That’s why a detailed site assessment should always be undertaken to ensure the best solution.

Once designed and installed correctly, these gabion systems should last for decades,” Cheyne concludes.

The double-twisted hexagonal wire mesh used to form gabions used in riverine environments is designed to flex under normal and flood conditions

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BITUMEN & ASPHALT

Meeting demand for high-grade bitumen AECI SprayPave is now able to offer the asphalt industry scarce 10/20 penetration-grade bitumen using unique technology that enables the production of specialist bitumen products. It is a major breakthrough that supports growth in the local roads sector going into 2021.

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esponding to the ongoing bitumen shortage in South Africa, the company acquired a multistage bitumen conver ter from Technix Industries in New Zealand in 2015 – only the second to be commissioned worldwide. The technology enables AECI SprayPave to achieve predictable and repeatable conversion of penetration-grade bitumen available from South African refineries to grades that are both lower in penetration and higher in softening point than the feedstock bitumen.

“We are ver y excited to be able to add 10/20 bitumen, which is currently in short supply, to our offering,” says Eddie Jansen van Vuuren, director, AECI SprayPave. “The 10/20 bitumen product conforms to the penetration-grade bitumen specification.”

EME and high traffic routes This 10/20 bitumen is commonly used in the production of high modulus asphalt (EME), which is well suited to highly trafficked

roads likely to suffer significant fatigue and stress. Currently, this grade of bitumen is only supplied by one South African refinery.

Other local refineries have not been able to produce 10/20 bitumen due to higher demand for other ‘normal’ grades and difficulty in meeting the required specifications. Unforeseen breakdowns and scheduled shutdowns at refineries add to the problem, points out Jonathan Bell, technical manager: Cape Town, AECI SprayPave.

The multistage bitumen converter uses pressure, heat and air to precisely convert bituminous refiner y feedstocks into high grade bitumen. The softness, penetration index and physical properties of the bitumen can be changed to meet exact design specifications.

Jonathan Bell, technical manager: Cape Town (left), and Eddie Jansen van Vuuren, director at AECI SprayPave, with the multistage bitumen converter, which enables the production of 10/20 penetration grade bitumen

The controlled processes in a bitumen converter make it possible to rearrange chemical structures to create asphaltenes.

The gentle process and highly efficient addition of air, and therefore oxygen (air rectification), preserve the highly polar aromatic/resin fraction and minimise coke build-up.

Comprehensive bitumen line-up In addition to the 10/20 product, the current bitumen line-up offered by AECI SprayPave includes 70/100, 50/70 and 35/50. “The converter has enabled us to deliver SABScertified 50/70 bitumen to the Western Cape since it became fully operational three years ago, with steady expansion of the product range since,” explains Bell.

The value of this technology to the local asphalt sector was highlighted when only soft-grade bitumen was available locally and the converter was able to overcome this shortfall through the successful production of 50/70.

“Our technical relationship with the plant manufacturer, Technix Industries, remains strong with a high level of collaboration to deliver value to Southern African customers,” Bell continues, adding that throughputs of 30 to 60 tonnes per day can be achieved when converting from conventional 70/100 to 10/20.

Herman Marais, technical director, AECI Much Asphalt (AECI SprayPave’s parent company), says the demand for EME incorporating 10/20 penetration-grade bitumen is growing in South Africa, where the technology is proving valuable for hightraffic-load routes.

Marais adds: “Demand is anticipated to increase exponentially when the major N3 freeway contracts are awarded, as several of these projects will use EME.”

BITUMEN & ASPHALT

NME innovations for Africa To ensure available funds are spent wisely, design engineers need to consider the most appropriate construction techniques, says Martin Murphy, managing director, GeoNano Technologies.

These include the proven benefits of new-age modified emulsions (NMEs).

T

he new-age modification of surfacing materials can substantially improve a road’s structural characteristics. For example, binders can be modified to, inter alia, have a higher resistance to ‘ageing’ (oxidation of volatiles, which results in brittleness of binders and cracking) under the harsh environmental conditions experienced on the continent.

Furthermore, new-age modifiers increase the maintenance-free life of the surfacing and provide user-friendly materials ideally suited for maintenance activities, resurfacing and the surfacing of new roads. Since they are placed at ambient temperatures, considerable savings in energy input are realised.

The placement of surfacings at ambient temperatures also makes NME ideally suited for labour-intensive construction and maintenance actions. Workers can safely work with the materials, which are modified to adhere to stone/gravel/sand. The modified binder is much less likely to contaminate equipment or adhere to exposed skin.

ABOVE Preparation of GeNANO anionic NME slurry next to the road RIGHT Placement and spreading of the GeNANO anionic NME slurry on existing surfacing

Through the introduction of nano particles less than one thousandth of the size of a bitumen particle, NMEs ensure a high depth of penetration is achieved on existing seals. They further provide a permanent waterrepellent benefit to the application.

Such applications will add considerable maintenance-free durability to existing surfacings at a fraction of the cost.

Preparing an NME slurry-mix can be carried out next to the road (using simple equipment like a concrete mixer). The placement is equally straightforward using squeeze brooms to ensure that all surface cracks (including micro cracks) are thoroughly sealed.

GeNANO Clear-seal protection of the crush-stone base layer showing the impact achieved under the action of heavy vehicles after some rain

Clear-seals

Martin Murphy, managing director, GeoNano Technologies

The use of GeNANO nano-silane nanopolymer sealant provides a Clear-seal option with additional benefits. Due to the size of the particles used, a water-resistant, highpenetration protective layer is achieved.

The application is dry within an hour with no ‘pick-up’ or contamination of vehicles and no repainting of road-markings required.

It is easily applied by hand with little training at about 2 ℓ/m². The sealant is also ideally suited for the prime of an exposed base, protecting the base layer against water damage

and vehicle trafficking. A double application of the GeNANO Clear-seal can be used on gravel/ soil roads to protect the gravel layer. It provides a surface with a ‘natural’ look while protecting it from water damage, achieving a high depth of penetration on an existing compacted layer.

“GeNANO NME is not a ‘one-size-fits-all’ solution. Adjustments to formulas are made based on the material, minerology analyses and the structural engineering requirements that must be met. Once those parameters have been determined, however, the correct NME application provides a cost-effective and workable solution,” Murphy concludes.

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25

PPC has been in business for close on 129 years and has become a household brand in South Africa. IMIESA talks to Dave Miles, head: Materials Business Unit, PPC, about market gains and growth strategies in this multifaceted segment.

How is PPC responding to the business challenges in the Covid-19 environment?

DM Fortunately, we were already well positioned to weather the storm and continue supporting our customers. Of course, we all know that the sudden arrival of Covid19 put the handbrake on projects across the South African industry.

Despite this, PPC has continued to forge ahead, thanks to our strategic marketing and forwardthinking approach. Adaptability, flexibility and diversification have been key contributing factors to our success. A prime example is the establishment of our Materials Business Unit around 2010.

Ongoing acquisitions form a key part of our expansion strategy. In 2013, for example, we acquired

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IMIESA January 2021

Pronto Readymix, as well as Ulula Ash. Then, in 2016, we bought 3Q Readymix.

Currently, we operate 27 readymix plants, two ash plants, and four aggregate quarries (two in South Africa and Botswana, respectively). Our South African quarry operations, both situated in Gauteng, comprise Mooiplaas and Laezonia. The latter is the only quarry in Gauteng with an amphibolite deposit. Being a very hard material, amphibolite is the best-in-class material for the roads market.

How has Covid-19 affected PPC Materials and its contributions to infrastructure?

Overall, our product lines – namely

Creating new possibilities aggregates, fly ash, readymix and premix – all performed well. In fact, our Ash business had one of its best trading years during 2020, spurred on by a huge demand for bagged cement from the formal and informal home building market.

The bulk of cement sold in South Africa has some sort of extender, whether it be slag, fly ash or limestone. Therefore, thanks to increased PPC bagged cement sales, our Ash business boomed.

Going forward, we will be expanding the PPC Fly Ash business with new contracts that have been awarded to Ulula.

We’ve been very active in supplying large private industrial developments, especially in Gauteng, with some government work. Residential building also started to rebound from May 2020.

However, within regions like Limpopo, North West, and Mpumalanga, mining infrastructure developments were postponed in 2020, as mines held back on capital expenditure.

The Aggregates business did exceptionally well, especially in terms of our readymix volumes.

Other key sectors like the chemical, metallurgical and agricultural industries performed with mixed results depending on how the pandemic impacted their business operations.

Significant growth in construction aggregates during 2021 will be dependent on additional public infrastructure investment, particularly in roads.

How has PPC Materials been able to support SMME builders?

To sustain our Materials business

Dave Miles, head: Materials Business Unit, PPC

HOT SEAT during 2020, we looked for additional opportunities. Given the rise in bagged cement demand, we decided to do more in-depth research on the micro CPM (concrete product manufacturers) and building materials sectors in some of our larger townships. Our investigation showed that SMME builders generally felt PPC was too large to engage with directly.

We saw this as an opportunity to adapt our business model to match their expectations and requirements. This included implementing systems and processes at our weighbridges to make it easier to do business with PPC and servicing smaller loads at the quarry.

Our business philosophy is to sell the value based on a non-negotiable commitment to product quality. We shared this view with our SMME client base.

The point driven home was that substandard quality is bad for any business. The precast concrete masonry bricks produced by micro CPM enterprises in the townships are a case in point, often using the cheapest materials at hand.

Producing better bricks has lifted the standard of building in these townships and provided a competitive advantage for qualitydriven SMMEs. Homeowners benefit from a structure that should now last for generations.

How is the premix product line developing?

Today’s professional teams are seeking faster and more efficient construction solutions.

In response, PPC’s research and development teams have focused on technical,

fit-for-purpose products.

That’s where our premix range comes in.

Instead of workers having to mix on-site, with varying results, our premix products (dry mortars, plasters and screeds) are readymade, which achieves two things: major savings on time, and consistent quality assurance.

A growing number of contractors recognise the advantages. For example, the contractor at Tembisa Mall, completed in 2020, exclusively used PPC’s premix plaster, accelerating the overall construction programme and opening date.

For larger projects, we supply PPC SureMortar and SurePlaster (mortar and plaster) in 30 t silos and some 90% of our business is done this way. These silos feature an integrated continuous mixer. All the contractor needs to do is add water for an instant mortar. As a further plus, we blend our cement with extenders and numerous admixtures to make the product easier to use, even by semi-skilled workers – making the premix range ideal for Expanded Public Works Programme and labour-intensive construction projects.

The price per tonne might be more for premix, but this greatly outweighs the business and reputation risk of having to go back to site to fix defects.

Does PPC Materials’ readymix team provide custom solutions?

Definitely. This is one of the ways we demonstrate our

ability to create ‘out of the box’ engineered solutions. A prime example is the DSV warehousing complex in Kempton Park, constructed in 2020. The main DSV warehouse covers an area of around 110 000 m2.

The developer approached us with very stringent performance requirements for the concrete mix. Together with our technical team, mixes were developed that met all the stringent technical requirements the professional team had. The scope entailed the pouring of 200 mm thick concrete floor panels, with joints every 2 500 m2. (For traditional slabs, the joints are installed every 25 m2.) To achieve the end goal, we worked with the client to design a unique readymix recipe.

The project was a huge success, with evidence of zero cracking.

Will the PPC Sure bagged range be extended in 2021?

Last year, we launched the SureMortar and SurePlaster bagged products. Customers can watch this space, as we continue to develop application-based products that customers need.

What is the project pipeline looking like?

We’re busy across the board.

In the roads segment, we’re currently supplying two major upgrade projects on the N4 between Rosslyn and Brits, and Witbank and Middelburg.

We are also negotiating with Eskom for further opportunities to source and process other ash dumps within their power station network.

On the readymix side, we’re investigating new supply opportunities in the renewable energy sector (wind farms and solar PV), as these projects start to gain momentum during 2021. We also expect mine infrastructure expansions to recommence this year.

Can PPC Materials make a difference?

Absolutely. We recognise the vital importance of providing a basket of products to our customers, irrespective of their size, or the scale of the project. This, combined with our expert technical support, makes the difference. Together, we are significantly stronger as we rebuild South Africa in the present and post-Covid-19 environment.

www.ppc.africa

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SOLID WASTE MANAGEMENT

Tshwane ready to up its waste game In the last three years, the City of Tshwane has closed the Derdepoor t, Valhalla, Temba, Kwaggasrand, and Garstkloof landfill sites. With only four sites still operational, the metro has seen a rise in illegal dumping over the years; however, planned strategies are in place to curb this. By Nombulelo Manyana

S

peaking at the IWMSA’s Waste Crisis in Gauteng seminar in 2020, Abel Malaka, head: Waste Management Department, City of Tshwane, said the city is focusing on initiatives that will secure waste disposal facilities for better waste management in Tshwane. These include the acquisition of private landfill site airspace, alternative waste treatment, as well as landfill site closure plans and alternative landfills.

Closure plans and alternative landfills Malaka indicated that four sites have been identified and recommended for feasibility studies for new landfill sites.

For the city’s existing Temba, Onderstepoort, Kwaggasrand and Garstkloof landfill sites, a closure application has been submitted to the Gauteng Department of Agriculture and Rural Development (GDARD) for consideration.

The sites will now alternatively be used as a garden waste site or waste transfer station, where municipal solid waste is temporarily held and sorted before heading to a landfill or waste-to-energy plant. Garbage trucks that run city routes drop off their trash here before it’s loaded on to larger vehicles and shipped off.

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IMIESA January 2021

The Onderstepoort landfill is also in the process of submitting a final report for closure, also for consideration by the GDARD. It will be used as either a garden waste site, transfer station or rubble crushing plant. Another consideration is turning it into a materials recovery and energy facility, which will receive recyclable materials and then use a combination of equipment and manual labour to separate and densify materials in preparation for shipment to end-user manufacturers.

Kwaggasrand is already being used as a materials recovery facility, while the Garstkloof landfill site will be used as a rubble crushing plant and waste sorting facility.

Alternative waste treatment Malaka said the acquisition of airspace is a short-term solution for the city, which is currently in negotiations with private landfill owners for the outright purchase of airspace.

Faced with dwindling landfill space for waste disposal, the Gauteng Infrastructure Financing Agency (GIFA) was appointed in March 2015 to conduct a feasibility study into alternative waste treatment methodologies.

GIFA and the City of Tshwane signed a memorandum of understanding on the project in May 2016 and, upon completion of the feasibility study, GIFA recommended a waste-

to-energy plant for Pretoria West power station and Rooiwal. The city will be approaching private energy companies to convert Pretoria West coal power station into an incinerator, based on the outcome of the feasibility study.

The city is also expected to announce large waste-to-energy projects for its landfill sites and wastewater facilities.

Improving landfill site compliance Tshwane was recently labelled as having some of the most non-compliant landfill sites in the country. Three of Tshwane’s landfill and waste disposal sites faced imminent closure in 2019 due to non-compliance with the conditions of the permits/licences under which they operate.

Malaka said the city is developing an action plan to ensure compliance and is doing an audit report on landfill sites conducted by the department.

An airspace assessment and financial provision report has been completed. In addition, the city appointed a panel of service providers to undertake surface water and groundwater monitoring, as well as an independent external audit, which has advanced a report to motivate for external landfill site operations and management.

SOLID WASTE MANAGEMENT

4IR in the waste sector

E

mbracing the Fourth Industrial Revolution (4IR), Averda South Africa has been rolling out its new Deliver y Management System, which entails equipping each of its vehicles with onboard mobile technology, and each crew member with their own digital login. This means that Averda knows the exact location and the real-time progress in service of all vehicles and staff on the ground.

This kind of digitisation within the waste management industry has been around for two years and includes Averda’s TruTrak, which provides its healthcare clients with end-to-end visibility in the collection,

has deployed these technologies, the company has found an average 15% reduction in fuel use and less time on the road.

Smart waste management transportation and disposal of potentially infectious medical waste. Every container of medical waste is traceable from collection through to final safe disposal.

“The adoption of these digital technologies and systems will change the way we serve and interact with our clients,” says Ablé van der Merwe, national logistics manager, Averda.

Dynamic oversight and control of these real-time systems provides support to Averda crews. They also permit intelligent route optimisation, which has the potential to minimise fuel consumption and maximise efficiencies. In other countries where Averda

South Africa is well known for illegal dumping and smaller, cheaper – but unreliable – waste collectors taking shortcuts, with many not knowing if their waste has been handled and disposed of correctly. It is important for all waste generators to keep and monitor these reports so that they stay within government regulations.

Many businesses and manufacturers are also still unaware of the kind of waste they may be producing and the harm this could be causing to communities and the environment.

However, through constant and accurate reporting, waste management companies and government can implement the best waste management practices for all.

Specialist Waste Management Consultants • • • • • •

Waste Collection Optimisation Waste Transfer Station design General Waste Landfill design Hazardous Waste Landfill design Landfill Rehabilitation Landfill Auditing and Monitoring

Contact Numbers

Telephone:+27 (0)21 982 6570 Fax:+27 (0)21 981 0868

• • • • • •

Landfill Closure Leachate Treatment Regional Waste Studies PPP Involvement in Waste Management Alternative Technologies for Waste Reduction Integrated Waste Management Plans

Physical Address

60 Bracken Street, Protea Heights South Africa, 7560

www.jpce.co.za

Postal Address

P.O. Box 931, Brackenfell South Africa, 7561

SOLID WASTE MANAGEMENT

The importance of post-closure management Protecting communities

Closed landfills must be properly managed and monitored for up to 30 years to protect the environment and neighbouring communities.

E

ven closed landfills can pose a series of threats to nearby residents and the environment, including odour generation, the proliferation of diseasecarr ying vermin, and sur face water and groundwater pollution from poor leachate management.

Capping is an integral part of the management of any landfill. Nico Vermeulen, operations director, EnviroSer v Waste Management, highlights that the capping system must be designed uniquely for each site, determined by the individual site’s design and the liner the site has underneath.

“Older sites would have a higher-spec cap. You want to do progressive capping on your site – as you have one or two cells that are filled, you should start the capping process, because this reduces leachate production, as rainwater cannot enter the site,” explains Vermeulen.

Typically, a capping system will have several layers: • a barrier, typically clay or a composite plastic liner • a top soil layer with vegetation on top of the barrier • a drainage layer that captures water

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IMIESA January 2021

that might leak through the clay layer, as well as any gases that escape from the site – these gases are collected through a pipe system and put through a whirlybird that has an activated carbon filter to absorb potentially odorous compounds in the gas.

• a system to collect any rainwater that falls on the sur face and remove it from the site.

Even with a capping system in place, it takes five to seven years for leachate to stop being produced. Installing and maintaining a good capping system and properly managing closed landfills is therefore vitally important to protect the environment and the growing number of communities living within close proximity to landfills.

Notably, the challenges associated with households living closer to landfills are less problematic when landfills are well designed and managed.

Dr Johan Schoonraad, group technical specialist, EnviroSer v Waste Management, stresses that the implementation of the correct buffer zone around a site is essential to prevent people encroaching too closely on the landfill. This also helps to prevent human activity on landfill site itself.

Landfill fires are a serious concern and can be caused by community activity on the site or the incorrect disposal of prohibited waste. In addition, well-designed and -maintained landfills circumvent the risk of the waste collapsing outside the bounds of the site, further protecting communities.

Schoonraad emphasises that where there are problems on closed landfill sites, remediation techniques should be employed to prevent potentially dangerous outcomes such as fire, pollution or collapse.

Ultimately, good management at both active and closed landfills comes down to compliance and enforcement, says Vermeulen. While the legislation is in place, it is up to the relevant authorities to tackle non-compliance and prevent the growing threat of illegal and unregulated dumps.

Water Wise Buildings On average, a commercial building uses approximately 37% of its municipal water in the kitchen and showers, 26% through leaking taps and toilets, 31% in watercooled air-conditioning systems, 3% in food production, 2% for cleaning and 1% on irrigation (depending on the landscape style, design, and size). By implementing modern plumbing systems, and implementing water management plans, commercial buildings can move to conserve water.

In order to practise Water Wise management in buildings, plumbing amenities should be checked and maintained regularly. To reduce water consumption in change rooms and ablution facilities, low-flow shower/tap heads should be fitted. These modifications can save between 80-90% of water by reducing water flow to 2 L/minute. Conventional taps in ablutions should be replaced with pop-up or sensor-activated taps. It is also essential to regularly inspect amenities for leaks and repair all leaks as soon as possible.

Professional leak detection services are often provided by plumbing companies.

Leak detection ensures that all underground pipework is mapped and traced. A lot of time and money can be saved by simply knowing where to dig to repair a leak.

Always be Water Wise!

www.randwater.co.za and click on the Water Wise logo FOR FURTHER INFORMATION ON WATER WISE, PLEASE CONTACT US ON: 0860 10 10 60

CAPITAL EQUIPMENT & PLANT HIRE

Why you should hire from CHPA members

The plant hire industr y fulfils an essential role for contractors and municipalities that need a shor t-term hire solution for a specific project phase, or a longer-term off-balance-sheet rental option. IMIESA speaks to Clive Wicks, CEO, Contractors Plant Hire Association (CPHA), about how the CPHA sets the standard.

T

he fact that the CPHA was formed in 1970 and is still in existence today is testimony to its role and value in promoting an ethical plant hire industry. All members adhere to strict protocols that include mandatory machine operator certification in accordance with South African legislation for the construction and mining sectors.

To ensure compliance, the CPHA is currently developing a database of licensed machine operators. In the past, certified courses were listed under the South Africa Qualifications Authority, but will be registered by the Quality

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IMIESA January 2021

Council for Trades and Occupations in future. The CPHA is monitoring the transition.

CPD authority On the training front, the CPHA has now been recognised by the Engineering Council of South Africa as a Voluntary Association and invited to become a Continuous Professional Development programme licensing authority.

Currently, machine classes, like cranes and earthmoving, require a baseline qualification, but nothing further. The CPHA’s

goal is to introduce more advanced levels of certification. Other plans include future proposals to the Construction Education and Training Authority for possible operator training funding and subsidies.

CAPITAL EQUIPMENT & PLANT HIRE

“Our role is to act as a quality gatekeeper to ensure that the highest standards are adhered to in protecting the public and the industry.

A prime example is our standard form of contract, which clearly stipulates the CPHA Conditions of Hire for customers nationwide,” says Wicks. “In addition to this, our members must have liability insurance in place and adhere to a Code of Ethics.”

CPHA Chambers For every machine class, there’s a CPHA Chamber. These include earthmoving, materials handling, small plant, compressors, generators, and mobile cranes. The CPHA also has a national branch network.

“As an association, we provide a single interface with government departments, SOEs and municipalities when it comes to issues such as procurement, tenders, and legislation affecting earthmoving machine licensing and legal on-road transport – permits for mobile cranes being a prime example,” says Wicks.

The latter is an especially complex issue for CPHA Crane Chamber members, as these machines share the road with other conventional and heavy-duty vehicles. Aside from general industry projects, mobile cranes are an essential component for specialised erections, including examples like the growing wind farm segment.

“We are constantly lobbying for a review of the permits. At present, mobile cranes are only allowed to travel on roads at specific times.

But what happens in the case of an emergency outside these times, like a petrochemical plant explosion? One of the metros we are now in discussions with is the City of Cape Town. Their current permit only allows mobile cranes to be on the road between 08:30 and 15:00,” says Wicks.

Keeping pace with technology Providing a first-class hire service clearly depends on fielding economical and efficient machines that result in the delivery of excellent service.

“Plant hire companies tend to be early adopters of technology,” Wicks explains. “The OEM products they acquire are also based on indepth research, and tried and tested experience. Fuel efficiency and lower cost maintenance are always key considerations.”

Owning or hiring depends on the business plan and project requirements. Today’s financially constrained environment may shift the balance more towards plant hire over the next few years.

Plant hire, for example, lowers the barrier to entry for new SMMEs securing work in the construction sector on an ad hoc, project by project basis. The CPHA also anticipates that there will be new entrants to the plant hire market as government’s infrastructure programmes gain momentum. This was certainly the case before and after the 2010 FIFA World Cup. “Our mission as the CPHA is to promote the benefits of plant hire and to provide public and private sector clients with the assurance that our members remain committed to the highest safety, operator proficiency and machine quality standards,” Wicks concludes.

Planers at the cutting edge

Angled cuts and the matching of two uneven surfaces are made possible by the planer housing, which can oscillate about 15 degrees

M

ore manoeuvrable than dedicated planers and cost-effective to maintain, Bobcat planer attachments are being deployed on many road rehabilitation and maintenance projects

in the country.

These durable and versatile attachments are designed for fitment on Bobcat compact track, skid-steer and all-wheel steer loaders. They are used to mate uneven pavement surfaces, clean around larger milling machines, mill around manholes, and taper edges on a road. They are also ideally suited for cutting drainage in parking lots.

Suited to arduous applications, Bobcat’s high-flow planers use the increased hydraulic horsepower of Bobcat loaders, which feature seven-pin Attachment Control Kits as standard. Standardflow planers provide contractors with a more cost-effective alternative for their periodic planning requirements.

Depending on the type of concrete, depth of use and operator experience, production rates of between 40 m²/h and 50 m²/h are possible using the various planer models. They include a 35 cm unit with a 35 cm all-purpose drum, as well as a 46 cm and 61 cm unit with or without the 46 cm and 61 cm Fast Cut Drum, respectively.

Carbide-tipped bits, mounted on a revolving drum, cut and pulverise pavement material, which – after being milled – exits the planer housing through a rear opening. It can then be immediately recycled to perfectly finish any asphalt and repair.

Comments Kevin Purcell at Bobcat Equipment: “Notably, the lowangle, high-velocity blows are undertaken in a controlled pattern to uniformly chip pavement, with depth, width and slope control easily set and maintained by operators.”

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ADTs on the production line

Delivering on South Africa’s infrastructure programmes requires an integrated approach, with capital equipment central to its execution. Alastair Currie talks to Leon Goosen, group chief executive at Bell Equipment, about the company's unique ser vice offering.

The right equipment,

the best support

How can Bell Equipment best support the South African construction market?

LG First and foremost, as experts in our field, we tailor our technical advice and aftersales care package strategy to match customer requirements.

This equally applies to new SMME entrants and toptier Construction Industry Development Board Level 9 contractors. Then, second, our operating philosophy is founded on the principle that if our customers are successful, we’re successful. Therefore, it’s a partnership approach from day one, which includes predictive and preventative maintenance support to maximise the customer’s machine availability.

Will 2021 see an increase in new work?

After several years of depressed trading conditions, the

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IMIESA January 2021

construction sector is expected to show signs of gradual recovery in 2021. There’s a sense of cautious optimism in the industry. Key catalysts include project roll-outs from Sanral, the implementation of government’s Economic Reconstruction and Recovery Plans, and allied initiatives like the Infrastructure Fund.

That means existing contractors will be reviewing their current earthmoving fleet and researching new acquisitions, rebuilds and upgrades. Government’s commitment to facilitating SMME growth also means that this will be a growth market.

There’s a definite willingness from the private sector to partner with government on infrastructure projects. Some of these will unfold as public-private partnership ventures – a prime example being the renewable energy sector.

Rather than taking a shotgun approach, the ideal would be for government to focus on priority projects that can make a more immediate contribution to socioeconomic recovery post Covid-19 – with roads and transportation infrastructure being at the top of the list.

Why is optimal machine selection so important?

For any contractor, capital equipment decisions can make or break a business. Machine acquisitions need to synchronise with the business plan and the forward order book. Key questions that need to be asked and answered include whether the equipment purchased achieves the efficiency and longer-term availability needed to sustain business operations.

For example, does the OEM or distributor have adequate parts and service backup, and are they able to customise solutions

Leon Goosen, group chief executive, Bell Equipment

for your project? Then there’s the future resale value that needs to be considered, as well as whether the machine can be rebuilt for a second or even a third life.

Another major consideration is the life-cycle cost. Over the longer term, the initial machine purchase price works out to be a smaller portion of the cost over its working life when you factor in elements like maintenance and fuel burn. Therefore, buyers should not only base their decisions purely on the upfront price. After all, it’s a business tool, so customers need to appreciate that buying a premium product with worldclass support is the best decision they can make.

What should contractors consider when applying for finance?

CAPITAL EQUIPMENT & PLANT HIRE

The tenure of the project is the starting point. Banks will ask for demonstrated performance and positive cash flow. That makes it paramount that infrastructure work packages awarded to contractors, especially SMMEs, are sustained by a constant pipeline of new work.

Our Bell Finance Division enables customers to structure machine payments to best suit their needs. In South Africa, as well as internationally, we form strategic alliances with financial institutions to ensure competitive deals. We are not short-term sellers. Our responsibility is to advise our customers and to support them.

How does Bell Equipment manage its local and international markets?

From inception, our passion for research, development and product innovation has been our foundation for success. That goes back to the 1950s, when our founder, Irvine Bell, offered specialised machines to meet the needs of the sugarcane industry.

In modern times, we’re especially proud of our global class leadership in articulated dump trucks (ADTs).

Our OEM products are designed and manufactured at our Richards

Bay factory in KwaZulu-Natal for South Africa and the world, supported by a second factory in Germany. Today, we are represented across the globe in key markets that include Africa, Asia, Europe, the Middle East, and the Americas. While we have our own Sales & Distribution operation in South Africa, we have largely migrated to a dealer model in other regions, as experience has shown that this option provides better coverage and support to customers in certain markets.

Global experience strengthens our capacity to deliver excellence in the local market. The same is true internationally in core markets like the UK and USA. We are a major competitor in the global ADT market, competing against the world’s largest and most respected brands.

will continue to refine our Versa custom range and refine the next generation of ADTs. We can proudly say that we are regarded as the global leader in ADT innovation. In every industry sector that we support, our product design engineers study how to make production sites safer and more efficient.

That includes inter-machine communication, remote and automated control. Again, it’s an integrated solution aimed at bringing down the overall cost of the job. Future investments in information and communication technology will also increasingly transition our after-sales services into the digital space.

Which major new product launches are planned for 2021?

Business is easier for customers when they only have one supplier and one point of contact for their equipment needs, particularly if that supplier delivers strong, reliable support. So, as an OEM, we focus on our niches and then, to provide holistic fleet solutions outside our core areas to customers in Southern Africa, we have formed strategic dealership alliances with other

We’re excited about the launch of our Tracked Carrier into the American market, in response to a niche demand there for this product. Locally and internationally, we’ll also be unveiling a new low-profile underground mining truck.

Alongside this, our R&D teams

How do your OEM distributor agreements complement Bell Equipment’s growth strategy?

Bell Equipment’s Richards Bay factory

globally respected OEMs. Our first was with John Deere, over two decades ago, to sell and support their construction and forestry equipment.

Since then, we have entered into agreements with the Fayat Group to represent the Bomag road construction equipment line, and with Finlay, a global leader in mobile crushing and screening. Our newest alliance is with Japanese excavator manufacturer Kobelco, which has further strengthened our offering by providing opportunities in the forestry industry.

What about training and transformation?

Bell Equipment has one of the largest apprenticeship training programmes in the country, and that’s key to the future. We train more than we need; we train for the industry.

Alongside this is our investment in our employees. We are proud to say that our Richards Bay factory and our Sales & Distribution companies are both 51% black-owned. A BBBEE Level 1 contributor, our Sales & Distribution company is also 30% black-woman-owned. We are firmly committed to building an inclusive business.

As a proudly South African company, we’ve embraced transformation and are committed to sustained local investment.

Most importantly, we’ve empowered our people to provide South African customers – and customers around the world – with mechanised solutions that compete on a level footing with the world’s best.

Is Bell Equipment ready for 2021?

Absolutely. The foundation of any growth strategy in this business is that you need to have reliable and strong products, with equally reliable and strong support.

We’ve achieved this.

IMIESA January 2021

35

CAPITAL EQUIPMENT & PLANT HIRE

Built to perform

E

ntering the local market in January 2021, Hyundai Construction Equipment’s latestgeneration HX220S excavator targets the highly competitive medium class.

The machine comes equipped with features that include variable power control, a singlelayer cooling system, a reinforced bucket and bucket linkage, and powerful and precise swing control for optimal production cycles.

Other design features include an improved intelligent display, easy-to-reach control panels, and improved all-round visibility.

Supplied and supported locally by HPE Africa, the machine is sold with a two-year/ 3 000-hour Hyundai factory warranty.

“What’s notable is the engine of this series, which has been designed with 40% fewer parts than other machines in the same

The Hyundai HX220S excavator has an operating weight of 21 260 kg and comes equipped with a 1.2 m³ bucket

class,” explains Ross Collard, managing director of HPE Africa, adding that the weight of the machine has also been reduced, without compromising the excavator’s strength or efficiency.

Weighing in at around 21 t, the HX220S should prove popular with contractors, plant hire companies and municipalities looking for a utility machine. Here, the HPE Africa team works closely with each customer to modify

equipment, when necessary, to meet exact performance requirements.

Machine versatility can also be extended with the specification of Soosan hydraulic breakers and quick couplers, distributed in Southern Africa by HPE Africa. Notable features include a high power to weight ratio for optimum efficiency and a patented valve system, which is synchronised with a simple hydraulic system.

Reinventing modular energy storage

A

tlas Copco’s ZenergiZe unit is an innovative modular energy storage solution with highdensity lithium-ion batteries at the heart of the system. Two operational platforms are available, namely Island and Hybrid Mode.

In Island Mode, the unit can be used as a standalone power solution and is recommended for job sites where noise or pollution concerns prohibit the use of a generator. Alongside zero noise and night environments, this mode is also ideal for remote telecom, rental and varying or low load applications.

The Hybrid Mode can be used together with any diesel generator. “This combination offers smart load management by enabling end-users to map load demand better,” explains David Stanford, business line manager: Portable Products at Atlas Copco Power Technique.

“Once end-users have determined what they need to power, and the relevant load cycles in terms of high and low load demand, they can run the genset under fixed load while charging the ZenergiZe’s lithium-ion batteries so that it’s

36

IMIESA January 2021

ready to take over when load varies,” Stanford continues. This Hybrid Mode solution is ideal for use in a range of demanding applications, including events and urban construction.

Using a fixed-speed 1 000 kVA genset to operate small tools like a 20 kW drill is extremely inefficient. In contrast, the ZenergiZe in Hybrid Mode is ideal for small

tool operation, presenting end-users with significant cost savings.

ZenergiZe units incorporate numerous connectivity features and benefits, including a smart start and stop function, an energy management system, a remote monitoring system, a Bluetooth mobile application, and parking mode.

ZenergiZe is designed with sustainable energy delivery top of mind; after a single 1.5-hour charge, the unit is ready to provide over 12 hours of power

CAPITAL EQUIPMENT & PLANT HIRE

Built to keep on performing

K

emach Equipment is the distributor of JCB earthmoving equipment, McCloskey crushing and screening equipment, Stampede compact compaction equipment, and Kemach forklifts in South Africa.

Equipment that is built tough and engineered to perform. The company was established in 2003 and has grown

to be a recognised and respected supplier in Southern Africa.

As a leading earthmoving solutions dealer, Kemach Equipment supplies high-calibre equipment to the mining, construction, quarrying and plant hire industries, as well as local municipalities and governmaent departments.

A focused dealer of distinguished equipment and support, Kemach

Equipment continuously strives to put the customer at the heart of its business, dedicated to meeting each client’s unique needs. The company operates throughout South Africa.

Kemach is now able to offer solutions across a wider spectrum of industries in South Africa, never resting on its laurels and continuously looking for opportunities to better serve its markets.

DISTRIBUTORS OF

WORLD-CLASS EQUIPMENT

www.kemach.co.za

Contact your nearest branch today JOHANNESBURG +27 (0) 11 826 6710 MIDDELBURG +27 (0) 13 244 1839 PRETORIA +27 (0) 12 548 2956 BLOEMFONTEIN +27 (0) 51 432 3978 DURBAN +27 (0) 31 700 8278

RICHARDS BAY +27 (0) 87 357 8985 CAPE TOWN +27 (0) 21 949 7442 GEORGE +27 (0) 44 878 0366 PORT ELIZABETH +27 (0) 41 453 1819 EAST LONDON +27 (0) 43 732 190

The road ahead with Ammann The APH 5020’s two-shaft exciter system delivers powerful compaction forces

An Ammann PTR leads a series of Ammann asphalt double-drum asphalt compactors. All Ammann PTRs come standard with ‘air on the run’, which enables the operator to deflate or inflate the tyres during operation

After a long hiatus, the South African construction industry is expected to rebound in 2021, spurring renewed demand for capital equipment. IMIESA speaks to Craig Sheppard, national product manager at ELB Equipment, about the strength and value of the Ammann brand, which has a proud OEM heritage.

W

ith a history dating back more than 100 years, ELB Equipment has an in-depth understanding of the capital equipment market, providing integrated solutions for construction, mining, quarrying and general industry. Premium OEM brands within the construction and earthmoving equipment portfolio include Ammann, Ditch Witch, Hidromek motor graders, MST backhoe loaders and Sumitomo excavators.

“These high-performance products cater for each stage of the road construction programme, from the base and sub-base layer works to the final asphalt surface,” says Sheppard.

ELB Equipment focuses on providing packaged solutions for emerging and top-tier contractors, municipalities and government departments, and has a dedicated Tender and SMME Department.

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IMIESA January 2021

“In the past two years, we’ve significantly grown our SMME customer base by providing consistent after-sales support.

To assist SMMEs, for example, we offer extended payment terms, which is hugely beneficial for new companies that struggle to get capital equipment finance,” he continues. “It’s the ease of doing business with ELB Equipment that makes our longer-term customer relationships so successful.”

For the road construction market, the Ammann line provides a comprehensive range of solutions for compaction and paving. Machine classes comprise singleand double-drum rollers, pavers, and pneumatic tyred rollers (PTRs).

Paving and PTRs At the top end of the market, Ammann pavers compete with the best. At the other end of the scale, Ammann has also

CAPITAL EQUIPMENT & PLANT HIRE

demonstrated its ingenuity by developing what is believed to be the world’s smallest paver – the AFW 150-2. Designed for jobs with a paving width of 0.8 m to 1.3 m, this unit weighs just 1 150 kg. Meanwhile, Ammann’s flagship paver, the 20 t AFT 900-3, can work to a width of 14 m with extensions.

In South Africa, most paving widths range between 3.8 m to a maximum of 5 m (for Sanral-type projects) and, locally, ELB Equipment sells and supports four key paving models. Three can be supplied in either tracked or wheeled configuration, the largest being the AFW 700-2, which has a working width of 2 550 mm to 6 600 mm.

With various ballast options, PTR operating weight configurations range from approximately 9.4 t to a range-topping 28 t. All Ammann PTR machines come standard with ‘air on the run’, which enables the operator to deflate or inflate the tyres during operation.

Soil and asphalt compaction The Ammann double-drum asphalt compaction range extends from the ARX12 (operating weight approximately 1 475 kg) to the 13.1 t AV130X. The mid-range Ammann AV70X, with its approximately 8 t operating weight, is a mainstream choice for contractors, being well suited to Sanral projects.

Single-drum soil compactors start at 10 t to 12 t, with the ASC100 and ARS122 units, and end with the ASC250 flagship model, which weighs in at between 25.5 t and 30.5 t. All single-drum units can be fitted with an optional padfoot shell kit.

As testimony to Ammann durability, one of South Africa’s leading contractors owns an ASC100 roller with over 60 000 hours recorded. This machine is used in a demanding 24/7 coal compaction application. “Aside from routine maintenance, the frame integrity of this machine is still near perfect,” Sheppard explains.

Another one of ELB Equipment’s customers now has over 50 Ammann ASC100s in their plant rental fleet, underscoring the popularity of these units.

Smart compaction “One of the most popular single-drum rollers, locally and internationally, is Ammann’s ASC110 machine (11.5 t to 15.5 t operating weight range), which features the optional ACEPro Smart Compaction feature,” Sheppard continues. “Essentially, ACEPro achieves intelligent compaction via a host of technologies to precisely measure and evaluate material stiffness, thereby delivering the optimum compaction result in the fewest number of passes. Over time, these efficiencies pass on major fuel burn savings.”

ACEPro continuously adjusts frequency and amplitude, depending on compaction measurements. It also eliminates drum jumping, minimising the risk of overcompaction or material destruction. As a further plus, ACEPro can utilise all major GPS products to provide mapping and operator guidance.

Ammann’s AFW 700-2 paver has a working width of 2 550 mm to 6 600 mm

Premium and Value ranges Depending on the machine model, Ammann compaction units are shipped to South Africa from their factories in Europe or India.

Ammann’s fabrication centre in Ahmedabad, India, recently underwent an approximately €85 million (R1.58 billion) upgrade to bring it in line with the group’s factories worldwide.

Units despatched from Ahmedabad to South Africa comprise the 11.5 t ARS122 singledrum roller (the equivalent of the European spec ASC100), and the 9.2 t ARX 91 doubledrum roller. “Being more competitively priced, these two models form part of our Value Line,” Sheppard explains.

Ammann single- and double-drum rollers destined for the South African mining and construction market come with fully enclosed and air-conditioned cabs, together with ROPS and FOPS, in compliance with health and safety stipulations.

Light equipment range Within the construction mix, Ammann also fields a light equipment line that includes rammers, vibratory plate compactors, a walkbehind pedestrian roller, and a specialist remote-controlled trench roller.

Ammann’s ARW 65 walk-behind roller comes equipped with a hydrostatic transmission and features two amplitudes – one for asphalt and one for gravel. This makes it an especially versatile machine.

“The hydrostatic APH 5020 vibratory plate compactor is a new addition to the Ammann range and promises to add real value on construction sites,” says Sheppard.

The APH 5020’s two-shaft exciter system delivers powerful compaction forces. In addition, the positioning of the exciter shafts enables the operator to easily change directions while working, while the hydrostatic drive allows for the machine to move easily in forward and reverse. Hovering and ‘on-thespot’ vibration can be utilised in particularly challenging areas.

“Within the civils and road markets, Ammann has proven mechanised solutions, with a major emphasis on practical and cost-efficient construction,” adds Sheppard.

“When ELB Equipment was appointed as the South African dealer some five years ago, the brand was still relatively unknown locally.

Since then, though, we’ve experienced a steady gain in market share. We anticipate that 2021 will see another surge in the local Ammann machine population as government commits to renewed infrastructure spend,” Sheppard concludes.

IMIESA January 2021

39

BIENNIAL PROJECT EXCELLENCE AWARDS

TUESDAY 16TH NOVEMBER 2021 CAPE TOWN

CALL FOR ENTRIES To recognise outstanding achievements in municipal infrastructure, we are calling for entries

Planning and design Construction methods

that showcase projects that demonstrate the best of civil engineering as a science and how engineering

Innovation and originality Meeting social and technical challenges

enhances the lives of the local communities, through excellence in:

Contributing to the well-being of communities

CATEGORIES

1

ENGINEERING EXCELLENCE IN STRUCTURES & CIVILS E.g. Projects demonstrating engineering science, use of alternate materials, innovative construction processes, etc.

2

COMMUNITY UPLIFTMENT & JOB CREATION E.g. Projects demonstrating labour-intensive construction, skills development, community awareness/participation, etc.

3

ENVIRONMENT & CLIMATE CHANGE E.g. Environmental rehabilitation, renewable energy, drought solutions, coastal initiatives for rising sea levels, pollution control, educational/ technical initiatives, etc.

CLOSING DATE FOR SUBMISSIONS 16 JULY 2021

Only projects that have reached practical or substantive completion by 30 June 2020 will be accepted for the Excellence Awards.

Adjudicators reserve the right to reallocate entries in the 3 categories.

ENTRY FORMS AND AWARD CRITERIA Available for download on the website: www.imesa.org.za

IMESA THE INSTITUTE OF MUNICIPAL ENGINEERING OF SOUTHERNÂ AFRICA (IMESA)

QUESTIONS Contact Debbie Anderson on +27 (0)31 266 3263 or email conference@imesa.org.za

CAPITAL EQUIPMENT & PLANT HIRE

Bell beefs up excavator range Bell Equipment, the exclusive distributor of Kobelco excavators in Southern Africa, is excited to introduce the new 10th-generation Kobelco SK220XD to its range. This unit bolsters the region’s 20 t class with a heavy-duty machine that is both highly productive and economical in all aspects.

T

he SK220XD-10 is loaded with features not usually found in 20 t machines – features that make this model well matched to Africa’s toughest mining and construction sites,” says Stephen McNeill, manager: Marketing and Alliance Partners, Bell Equipment.

“The SK220XD-10 has a rated power output of 118 kW at 2 000 rpm and a maximum torque of 592 Nm at 1 600 rpm. Like the current SK210 and SK260, it is fitted with a four-cylinder Toyota Hino engine, which has per formed exceptionally well in our construction, mining and forestr y industries. Bell has sold around 150 Kobelco machines with this engine since 2017,” McNeill continues.

Kobelco has always focused on hydraulic efficiency as the key to achieving maximum power output and lowest fuel consumption on its excavators. Reducing friction in the system means less energy is wasted and more work gets done with less fuel.

Arm Interflow System Stephen explains that this has been taken a step further with the 10th generation by introducing the latest hydraulic technology,

the Arm Inter flow System. “When lowering the boom, the system uses the downward force generated by the boom’s weight to push fluid to the arm cylinder. Essentially, the machine is using gravity to generate hydraulic energy, which means there is less demand on the hydraulic system and engine. Improved hydraulic efficiencies improve fuel burn, and the SK220XD-10 Kobelco claims a 19% higher fuel saving in ECO-mode compared to S-mode on the SK210LC-8.

“The SK220XD-10 also offers improvements to both the fuel and hydraulic filtration systems with a view to increasing durability and

The SK220XD-10 has a 1 m3 heavy-duty bucket, designed and manufactured by Bell Equipment with South African conditions in mind

longevity of an already reliable machine.

This makes them even more suited to our harsh South African conditions,” says McNeill.

Stronger and tougher Structurally, the machine is much stronger.

The SK220XD-10 has a 1 m3 heavy-duty bucket, designed and manufactured by Bell Equipment with South African conditions in mind. The boom and arm, which take the greatest punishment, are reinforced with thick steel plate for a more robust attachment, while long, solid rock guards prevent damage to the arm.

According to McNeill, the undercarriage has extra wear protection plates for increased durability compared to standard models. In addition, the travel system is more power ful and heavy-duty due to large, strengthened track guides, a reinforced travel motor cover, and robust guarding to protect the hydraulic piping and equipment.

He continues: “All Kobelco’s 10thgeneration machines have ROPScertified cabs, from the SK220 through to the SK520. The cabin is super-airtight, quieter and more comfortable than before, with 80 mm more leg room and a lighter, smoother touch with the controls. A full-colour multidisplay provides operational information, including fault codes, fuel consumption and maintenance details. A telematics system is fitted standard to the latest-generation models, which provides fuel consumption, location, as well as fault codes and warnings.

“From the excellent visibility to the layout and storage, we are confident that operators will find our SK220XD-10 comfortable and efficient to operate,” McNeill concludes.

IMIESA January 2021

41

CITY OF CAPE TOWN

Constructing for and with the community Community liaison and engagement is crucial for the successful execution of infrastructure projects in South Africa. Knight Piésold Consulting, working in conjunction with its client’s professional team, demonstrates how first-class results can be achieved on a complex programme delivered for the City of Cape Town Roads and Stormwater Department.

D

uring 2014, Knight Piésold was appointed by the City of Cape Town to design and manage the rehabilitation of Stock Road between Govan Mbeki Road and the R300 in Philippi. The design made provision for non-motorised transport (NMT) and integrated rapid transit (IRT) infrastructure, as well as the replacement of municipal services. The latter included electrical, water, sewer and stormwater infrastructure.

A key element included the rehabilitation and construction of a 2 050 m two-lane single carriageway into a two-lane dual carriageway.

These and other works were carried out by main contractor Martin & East, with all phases completed by July 2019.

“Project challenges included the relocation of unknown Eskom infrastructure from the proposed roadway into the roadside reserve, which was populated with existing services, as well as new approved services,” explains Naveed Sayed, Knight Piésold’s assistant resident engineer for the project.

“A crucial aspect was the safety and accommodation of very dense pedestrian and vehicular movement, including heavy vehicles accessing a myriad of business properties,” he continues. In addition to industrial and

Naveed Sayed, Knight Piésold

42

IMIESA January 2021

business hubs, crowding occurs around key transportation nodes that include Stock Road Station and the Joe Gabi Long Distance Bus Facility.

Another challenge presented was the effective engagement and buy-in from local taxis during the early stages of the project.

Their random stops and starts to collect and drop off passengers were causing major traffic congestion at the Rochester Road and Stock Road intersection. A solution was found after meeting taxi organisation officials via the project’s appointed community liaison.

This led to the establishment of a temporary demarcated taxi parking area. Soon after implementation, there was a significant reduction in congestion. A similar strategy was used for the safe accommodation of informal traders, with demarcated areas provided during each construction phase.

Informal settlements, business traffic Difficulties

and

complexities

were

also

experienced when informal settlements began occupying the road reserve once the contractor started establishing on-site. An instruction was given to amend the kerb alignment and design of the proposed roadway timeously before any more informal structures were built. This meant the redesigning and relocating of newly proposed services.

“A further issue that needed to be addressed was the inability of heavy vehicles to access business properties along Stock Road, following the installation of the new median,” says Sayed. “After extensive discussions and meetings with the client, provision was made to allow these businesses temporary access until such time as the planned IRT system is implemented.”

There was also much uncertainty regarding the exact positions and depths of existing services. The lack of reliable, as-built details and the presence of unknown services required ongoing, unavoidable design changes.

The infestation of illegal electrical power connections along Stock Road proved to be a major obstruction to many construction activities due to their odd locations. However, preventative measures were taken to ensure that these connections were not tampered with to avoid unintentional provocation of the local community.

Hard ground conditions The presence of calcrete rock meant that rockbreaking using machines had to be carried out alongside the fragile existing asbestos cement water main. This water main is the only water

Construction of bitumen treated base at Sheffield Road intersection

CIT Y OF CAPE TOWN

supply to the business hub and the informal settlement area of Stock Road. Failure of this line would have meant cutting off the water supply to this area for an extended period.

A further consequence of failure would have been the destruction of or damage to any existing electrical cables. This would have cut off power to local businesses and informal settlements.

A similar situation applied to all other services, such as sewer mains and stormwater systems. The loss of any of these would have had downstream consequences for residents and businesses along Stock Road.

Group participation For any community project to work, participation and buy-in are essential. For this project, David Leendertz Consulting was appointed as the community liaison. An open house before the tender stage ensured that all community as well as interested and affected party interests and inputs were allowed for in the design and contract stipulations, wherever possible.

Community liaison meetings were held at the Philippi Community Hall every two months throughout the contract. At each meeting, the project team gave a presentation on the current status. All present were permitted to ask questions, as well as obtain replies to questions sent to David Leendertz Consulting prior to the meeting.

Due to the extensive nature of the project, there were many opportunities available for local labour as well as local enterprises.

The contract participation goal targets for the contractor were 3% for targeted labour and 3.5% for targeted enterprises, which were well achieved.

Accredited training was provided to all local labour, as well as local subcontractors, in accordance with the Guidelines for the Implementation of Labour-Intensive Projects under the Expanded Public Works Programme.

A new form of mobility Since its completion, the project has opened a new world of possibilities when it comes to

ABOVE LEFT Installation of additional steel pipe water main ABOVE Temporary access was provided for heavy vehicles to access commercial properties

mobility. Catering for the high volume of nonvehicular movement in the area, the NMT facility now allows for the safe transit of cyclists and pedestrians to key facilities such as the business hub, railway station, clinics and taxi ranks. The project’s IRT infrastructure links up with the future Lansdowne IRT corridor.

“By embracing the complexities, the professional team has executed a newly rehabilitated road, services and ancillary works that considerably improve socio-economic well-being within one of Cape Town’s fastestgrowing urban areas,” adds Sayed.

The role of the client, the City of Cape Town Roads and Stormwater Department, is particularly acknowledged for its vision, valued input and support.

An aerial view of Stock Road Bridge

PROFESSIONAL TEAM Consulting engineer: Knight Piésold Consulting Electrical consulting engineer: GJA Consulting Engineers Structural engineer: Structural Solutions Contractor: Martin & East Community liaison consultants: David Leendertz Consultants Occupational health and safety: Safe Working Practice Environmental consultants: Ecosense Consulting Environmentalists IMIESA January 2021

43

CITY OF CAPE TOWN

Innovative use of builders’ rubble

B

uilders’ rubble is a valuable construction material and the Solid Waste Management Department at the City of Cape Town (CoCT) has recognised that it has no place occupying valuable landfill airspace.

The city is now maintaining separate stockpiles of clean builders’ rubble (less than 10% contamination with other material), which attracts a significantly lower landfill gate fee.

However, due to a struggling construction industr y and a perception in the public sector that builders’ rubble is a liability in construction, the large stockpiles of builders’ rubble at the Coastal Park Landfill had grown to approximately 450 000 m3, restricting operations and planning at the landfill. In response, the CoCT prioritised the use of builders’ rubble in the earthworks contract for the construction of its new materials recover y facility (MRF) at Coastal Park.

The process Site sur veys and geotechnical studies revealed that the builders’ rubble stockpiled at the landfill was suitable for the production of 19 mm aggregate, G7 and G9 materials (as per COLTO specifications) for the bulk earthworks and construction of detention ponds and a section of bioswale.

Furthermore, material suitable for the

44

IMIESA January 2021

production of both sub-base and base material for the layer works of access roads was identified for the above earthworks contract. In response, the tender document was tailored to require the inclusion of builders’ rubble, with pricing requested for both builders’ rubble, which on average was offered at a cheaper rate, as well as commercially available virgin material, thus driving green procurement.

Approximately 60 000 m3 of rubble sourced from the Coastal Park stockpile was subsequently used in the earthworks and bulk ser vices contract. Certain portions only required screening to produce suitable aggregate to meet the technical specifications, while other material was screened, crushed and, in some cases, blended to achieve the required grading.

The CoCT found that builders’ rubble is a useful construction material when the quality and per formance of the material is well matched to the application and recommends that municipal construction tenders make provision to favourably consider appropriate builders’ rubble sources.

The CoCT’s Green Procurement Action Plan is designed to facilitate the use of recycled or recovered materials in its operations and projects. Further projects at the Coastal Park Landfill, including the construction of a new landfill cell, are also designed to include locally available builders’ rubble.

As the CoCT continues to provide waste diversion projects, it hopes to increase the number of citizens participating in this sustainable behaviour.

CIT Y OF CAPE TOWN

Towards a water-secure future In just six years, the dams supplying Cape Town went from full to almost parched, as predicted rainfall did not materialise. It took three years for the dams to recover, and the city is now realising the objectives laid out in its Water Strategy to build generational resilience and water security.

T

he City of Cape Town (CoCT) drafted its Water Strategy during the peak of the recent severe drought. The strategy sets out plans to accelerate the development of new water sources to increase available water supply by 300 million litres per day over the next 10 years and reduce the reliability on surface water and risks associated with it.

“During this time, we all learnt harsh lessons about the finite nature of water availability, the unpredictability of rainfall and the reality of a changing climate,” says Alderman Dan Plato, executive mayor, CoCT. He adds that the data around collective water consumption indicates that the city’s relationship with water has fundamentally changed – likely permanently.

For the first time since restrictions were implemented, Capetonians are exceeding the requirements of water restrictions. Collective consumption hovers at around 650 Mℓ to 700 Mℓ per day – roughly 30% lower than historical levels.

Future water security While much improved water conservation has bought the city some time, droughts are predicted to become more frequent and intense, while the city’s population continues to grow. It is therefore vital for Cape Town to diversify its water sources and increase available supply. In this regard, the CoCT has

already made some encouraging progress in pursuing the New Water Programme.

The Table Mountain Group Aquifer is already providing 15 million litres of groundwater per day and construction has commenced on the Cape Flats Aquifer Scheme.

The city is also in the planning phase for a permanent desalination plant, which is provisionally scheduled for completion in 2026/27. The cost of a permanent desalination plant – which will produce approximately 50 million litres per day – is currently estimated at around R1.8 billion.

According to Plato, the temporary desalination plants constructed during the drought provided valuable handson experience in producing desalinated water. This has built confidence that desalination is a viable way of reliably producing good-quality drinking water and will assist in working towards larger-scale desalination projects.

In addition, the CoCT is working towards the implementation of a large-scale water reuse scheme by 2026 and continues to clear alien vegetation in its catchment areas. These efforts, along with the other projects in the New Water Programme, are designed to create a scenario in which high-level water restrictions, such as those recently experienced, should not be required again in the near future.

People collected natural spring water in Newlands during the drought

“Our Water Strategy commits the city to not only becoming water resilient, but also to provide a ser vice for all that includes improving water and sanitation ser vices in informal settlements, and to transform our relationship with water, by becoming a water-sensitive city,” says Alderman Xanthea Limberg, MMC: Water and Waste, CoCT.

Building a world-class utility Cape Town is also working towards becoming the first African member of the Leading Utilities of the World – a network of the world's most forward-thinking water and wastewater utilities. The objective of the initiative is to create a global network of the world’s most successful and innovative water and wastewater utilities, to help drive performance across the sector by recognising achievement, providing a network for sharing ideas, and inspiring others to improve.

“We are confident that the city’s innovations in this sector to date place us in a position to start building a case for entry,” says Limberg.

The Theewaterkloof Dam suffered extremely low water levels during the drought

IMIESA January 2021

45

CONSTRUCTION LAW

Covid-19:

Rethinking public sector tenders and contracts Despite the likelihood that the Covid-19 virus will be with us for many months to come, it appears that public sector construction tenders are not including clauses in their contracts to deal with the global outbreak.

By Natalie Reyneke*

M

DA Attorneys recently reviewed several tender packages and their accompanying contract conditions posted for public sector work.

The exercise revealed that not one of these tenders included a clause related to the pandemic.

As construction law specialists, MDA Attorneys has worked to clarify how the pandemic could and should be dealt with in contracts that are currently being negotiated and signed. This follows months of assisting contractors with claims relating to the nationwide lockdown and its impact on construction projects in the country.

Most claims envisaged the use of the force majeure provisions of contracts and, in some cases, clauses that entitle the contractor to benefits due to a change in legislation, and/ or unforeseeable shortages in the availability of materials or goods.

Clearly, the pandemic can no longer be seen as a force majeure event, having already occurred; in addition, the potential ramifications are no longer unforeseeable.

Although the specific contract form being used is key, we can assume that the ramifications are not only foreseeable (such as a move between levels of lockdown that could restrict movement) but that these ramifications could have been provided for under the contract.

Areas of impact To identify the relevant clauses and provisions that need to be reconsidered in new construction contracts, the various areas of impact caused by this event must be identified. The following was gleaned from what we have seen to date: • Works on-site were suspended or stopped as a whole (whether by instruction directly from the employer or its agent, caused by this unforeseen event, and further forced by regulation implemented by governments).

• Government regulations resulted in border closures (affecting international trade and shipping, further affecting the supply chain, materials and goods delivery).

• Restriction of movement by people (only allowed to work from home, demobilisation of people from the site, requiring additional travel arrangements for the workforce).

• Health and safety implications (additional measures had to be put in place, social distancing had to be applied, hand sanitisers, regular washing of hands, wearing of masks, immediate alertness, and actions to be taken regarding medical testing upon experiencing of Covid-19 symptoms, to name a few measures).

The majority of the public works tender documents reviewed incorporated the General Conditions of Contract for Construction Works (GCC), Third Edition, 2015, 2nd Print.

CONSTRUCTION LAW

For this reason, our suggestions refer to this contract form. It should be noted that provisions and suggestions mentioned are not comprehensive.

Amendments to applicable laws In terms of Clause 4.1.3: “The Contractor shall, in fulfilling the Contract, comply with all applicable laws, regulations, statutory provisions and agreements.”

Clause 6.8.4 states: “If at any time within 28 days before the closing date of Tenders or thereafter, any Act of Parliament, Ordinance, Regulation or by-law… is amended and this results in additional, or reduced cost to the Contractor… such additional or reduced cost shall, after consultation… be added to or deducted from the Contract Price.”

What this implies is that the contractor is only required to make provision in their tender for compliance with the laws applicable 28 days prior to the tender closing date. As the virus begins to resurge in several provinces, it is prudent to consider the implications of a prescription by the Occupational Health and Safety Act (No. 85 of 1993) for more stringent requirements within the time period from 28 days prior to tender closing. This would be an employer’s risk. Should another lockdown be prescribed under the Disaster Management Act (No. 57 of 2002), it may be seen as a change in the legislation that will yet again be an employer’s risk.

Events that occur after commencement instructions Clause 5.4.3 provides that: “The Employer shall, upon the Employer’s agent’s instruction to commence carrying out the Works… give the Contractor right of access to the Site and possession of the whole Site.”

Then Clause 5.4.3 states that: “If the Contractor suffers a delay to Practical Completion and/or incurs proven additional cost from a failure of the Employer to give possession… the Contractor shall be entitled to make a claim… (time and money).”

Should a Covid-19-related event occur after the employer’s agent has instructed the contractor to commence the carrying out of the works, will the employer get relief from a force majeure type clause?

Let’s unpack this. First, the term force majeure is not a recognised term in South African law and a definition of what force majeure means under the contract is generally provided for in each contract. The GCC does not use this definition. It uses the definition for “excepted risks” instead and sets out what these excepted risks are in clause 8.3. While the usual force majeure clauses found in contracts would suspend a party to the contract’s obligations if it would not be possible to perform them during the occurrence of the event, the GCC contract does not.

Clause 8.3.1 states: “The excepted risks are risks of damage or physical loss or any other loss caused by or arising directly or indirectly as a result or consequence of….

8.3.1.7 epidemic famine or plague.”

Clause 8.3.2 then states that: “If, in carrying out the Works, any of the excepted risks, other than pertaining to loss or damage to the works… causes the Contractor to suffer delay to Practical completion and/or brings about proven additional costs, the contractor shall be entitled to make a claim.”

Would the impact of the ongoing Covid-19 pandemic be seen as an excepted risk?

Clearly there are important considerations that need to be answered when employers are preparing documents for tender by contractors. Judging by what we’ve seeing to date, the risk all falls on the employer.

What can be done?

In the face of the ever-changing life cycle of the pandemic, employers may be faced with claims for not only time but additional money from contractors. It therefore makes sense to ensure that the pandemic and its potential impacts on the time and cost of a project are factored into the tender documents.

Our recent exercise of researching available tenders appears to indicate that this is not being done.

Should pandemic-related issues be a shared risk between both parties? Perhaps.

Considering that public sector projects are governed by strict budgets, however, it would certainly be

a waste for pandemic-related contractor claims to eat into budget contingencies for potential variations to the works. Of course, if additional costs due to the pandemic have been built into the budget, this is a moot point.

Employers need to be aware that identifying particular clauses or provisions of a contract for possible amendment is much simpler now, including: • delays and/or other events preventing performance, which will entitle a claim for extension of time with related costs • access, mobilisation, demobilisation to and from site • health and safety • price adjustment, escalation in supplier costs • types of insurances to be considered for proper cover relating to certain unforeseen events and the impact caused as a result • termination of the contract.

In summary, Covid-19 is likely to continue to wreak havoc on South Africa’s construction sector and parties need to be agile and prepared for further possible impacts. Not only is Covid-19 no longer unforeseen, but certain changes have necessitated new health and safety requirements.

When negotiating new construction contracts, the parties must carefully review the circumstances and expressly define Covid-19-related events as well as the entitlements to time and money that could be claimed by the contractor.

The risks and circumstances to each respective project will vary per project, so possible areas of risk to each particular project will need to be identified and researched. With this in hand, the provisions of the contract must be reviewed with a view to agreeing to clear, balanced duties and responsibilities for efficient, cost-effective operations. *Natalie Reyneke MDA Attorneys.

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IMIESA January 2021

47

CEMENT & CONCRETE

Minor concrete defects and their remedies Bryan Perrie, managing director, TCI

The durability of concrete is exceptional and well recognised but, sometimes, operational errors or unforeseen circumstances can cause unsightly, super ficial sur face damage, says Br yan Perrie, managing director of The Concrete Institute (TCI).

T

he quality of any cast concrete product depends on material selection, equipment used and workmanship. Sur faces of acceptable quality and accuracy are difficult to achieve and, depending on functional and aesthetic requirements, some repairs may be necessar y. Repairs may also be necessar y where sur faces are damaged in ser vice.

Minor defects include: • Small cavities: such as those formed by tie-bolts and impact damage to the sur face.

• Honeycombing: concrete in which mortar is partially or completely absent, caused by mortar loss during placement, or segregation of the stone and mortar.

• Misplaced surfaces: usually the result of incorrectly aligning or positioning

Blowholes are relatively small voids of roughly spherical surface shape formed against formwork or moulds, usually caused by inadequate compaction of the thin layer of concrete in contact with formwork, or the incorrect mould release agent for the formwork type

formwork, or movement of formwork during concrete placement. Under- or over filling of formwork may also be the cause.

• Blowholes: relatively small voids of roughly spherical sur face shape formed against formwork or moulds, usually caused by inadequate compaction of the thin layer of concrete in contact with formwork, or the incorrect mould release agent for the formwork employed.

Basic types of repair materials Repair materials are formulated to reduce the likelihood and severity of cracking.

This is done by reducing potential dr ying shrinkage, which will reduce the tendency to crack. Two approaches are possible.

The first approach is the use of ‘semi-dr y’ mixtures of cement, water and aggregate, compacted by being rammed into position.

Semi-dr y mixtures have low water content and therefore ver y low potential dr ying shrinkage – and a consequent resistance to cracking. But water content is critical: if too low, thorough compaction is impossible; if too high, the repair may slump or crack. These mixtures can be used only in confined spaces such as

The cause of honeycombing: concrete in which mortar is partially or completely absent, caused by mortar loss during placement, or segregation of the stone and mortar

48

IMIESA January 2021

CEMENT & CONCRETE

cavities and, ideally, applied by trained, experienced and skilled operators.

The second approach is the use of plastic mixtures of cement, water, polymer emulsion and aggregate (polymer-modified mixtures) applied by trowel or spatula to reduce the amount of water required for a given consistence. The hardened material, which incorporates a 3D network of coalesced polymer, exhibits greater creep and toughness. Consequently, potential dr ying shrinkage is relatively low, tensile stresses resulting from restrained shrinkage reduced, and cracking significantly reduced.

Selecting materials for repairs Repair materials are mixtures of cement, water and aggregate, with the possible inclusion of a polymer emulsion. In all respects, it’s important to note that cement must meet the requirements of SANS 50197 for Common Cement, and the National Regulator for Compulsor y Standards (NRCS) requirements as detailed in NRCS

VC9085. Bags should be clearly marked with the strength grade, notation indicating composition and a Letter of Authority (LOA) number issued by the NRCS. To verify valid LOA numbers, contact the NRCS on +27 (0)12 428 5199 or www.nrcs.org.za.

Water that is potable from a municipal simply is suitable, but needs testing to establish acceptability if from other sources. Maximum aggregate particle sizes must also not exceed a quarter of the thickness (or least dimension) of the repair and, preferably, be spherical. If such materials are unavailable, particles should be rounded, roughly cubical or ‘chunky’.

Flaky and elongated particles should be avoided.

Another important point to note is that sand used for repair work should have particle sizes ranging from dust to the largest size.

Sands with similar-sized particles produce mixes with poor workability and a high water requirement, and should be blended with other sands to improve grading.

The following aggregate types, blended where necessar y, may be suitable for repair work: - Plaster sand: useful for blending with a coarser sand to improve workability or on its own for making priming slurr y and filling blowholes.

- Concrete sand: naturally derived pit sands or river sands and well-shaped crusher sands, with coarse particles removed by sieving if necessar y and blended with a finer plaster sand.

- Stone pebbles and crushed stone with well-shaped particles.

- Polymer emulsions, formulated for use with cement, obtainable from specialist suppliers. Such emulsions should be based on styrene butadiene rubber or acr ylic.

For more information, visit www.theconcreteinstitute.org.za or email info@theconcreteinstitute.org.za

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CEMENT & CONCRETE

Precast concrete triple bases, each weighing 8.2 t

Experts in bespoke culverts

R

enowned for manufacturing specialist precast products, Rocla recently supplied South Africa’s largest customdesigned jacking culverts for a municipal project in Pretoria. This same ingenuity was adopted by Botswanabased sister entity Kwena Rocla, which was recently awarded a contract to design, manufacture and supply purpose-built culverts for Jwaneng diamond mine.

“With Komatsu 930E tippers at 530 t fully loaded, we had to ensure that our culverts could withstand this loading, as well as accommodate the electric shovel used, bearing in mind the fill is only 1.2 m,” says Philip Smith, operations manager/director, Kwena Rocla.

“We also had to meet the challenge of the culverts having to stand on double and triple base slabs due to the soil conditions experienced.

We created special moulds in order to produce these slabs,” Smith continues.

Kwena Rocla supplied 102 units of 2 000 x 1 000 at 1.2 m fill culverts, 244 units of 2 000 x 1 500 at 1.2 m fill culverts, and 288 units of 2 000 x 2 000 at 1.2 m fill culverts. Additionally, 217 of 2 000 double bases and 72 units of 2 000 triple bases were supplied.

Kwena Rocla produced and delivered these bespoke culverts ahead of deadline. Significantly, zero incidents/LTIs were recorded on-site and at the factory.

A 2 000 x 2 000 culvert

A triple base grid laid out for inspection

IMIESA January 2021

51

CEMENT & CONCRETE

Building precast wind towers that last

T

he average concrete wind turbine tower comprises 18 precast segments, each with a height of between 18 m to 20m and a diameter of between 600 mm and 2 m. In the manufacture of these precast elements, production speed and segment uniformity are essential.

Wind turbines must also be able to perform in some of the harshest working environments, making durability a key requirement. This is an area where Chryso Southern Africa is adding value on wind farm projects across South Africa’s Eastern Cape and Western Cape provinces.

The Chryso Fluid Premia range of plasticisers facilitates workability retention of between 30 and 45 minutes while achieving high early strengths.

These early strengths enable fast erection due to the quick turnaround time, as the mould release and prestressing release can be done earlier. The Fluid Premia range also maintains consistency in the manufacturing

FAR LEFT Chryso plasticisers improve cohesion, lower viscosity and increase concrete durability LEFT The Chryso Fluid Premia range maintains consistency in the manufacturing of reinforced concrete components

of reinforced concrete components, reducing the sensitivity of concrete to variations in water content.

Countering shrinkage Plastic shrinkage cracking and plastic settlement cracking can occasionally penetrate deep into a precast unit, inflicting significant costs in remedial measures and even replacement.

Applying a curing compound from the Chryso Cure range to the precast segments reduces the incidence of shrinkage cracks and promotes better strength-gain characteristics.

Curing compounds also increase the impermeability of concrete, making it more durable.

Another important product gaining traction in this market is a.b.e. duragrout. Developed especially for wind farm precast applications, this product is used for the grouting and bedding of structural elements. It can be pumpable, or gravity fed, and has good cohesive properties without bleed or segregation. It is pre-blended and ready to use, requiring only the addition of clean water.

Monitoring In a related development, Chryso has partnered with Maturix to develop an innovative sensor solution with a digital cloud platform to monitor the maturity of concrete. It has been used worldwide on more than 350 in situ and precast projects, and is being trialled on a wind farm project in South Africa. This cloud-based solution helps the construction industry monitor concrete curing and hardening through hydration temperature measurements.

Precast concrete segments were used to construct these 100 m tall wind turbine towers

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IMIESA January 2021

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