M&D Construction Group, a leading diversified South African contractor, and the company’s enterprise development joint venture (JV) partner, Motla Projects, a 100% black women-owned construction company, are nearing the completion of the construction of a new 1,4ML water tower in Aeroton, Gauteng.
The new water tower will enable Johannesburg Water to provide adequate storage capacity within the Aeroton sub-districts and improve existing supply into the distribution network.
It will also alleviate pressure on the Rand Water bulk supply system that directly feeds into the reticulation network by providing sufficient capacity to supply at least six hours of annual average daily demand and improve dynamic pressures in high-lying regions. With a top water level of 30m above ground, the tower has also been designed to meet future anticipated water demand in this industrial area of Johannesburg, Gauteng.
M&D Construction Group/Motla Projects JV was awarded the contract to build the water tower and ancillary infrastructure based on the company’s long legacy of successfully delivering critical water infrastructure in South Africa. These capabilities are being complemented by those of Motla Projects, which also has an impressive track record working on complex public-sector infrastructure projects.
Some of M&D Construction Group’s more recent related projects include the construction of a new 16ML wastewater treatment works in Vryburg, North West; a 20ML reservoir in Paarl, Western Cape; and the Sondela Booster Pump Station in Bela Bela, North West Province. These are complemented by a host of other water-related projects that the Pipeline Division has also effectively completed on behalf of public and private sector client bodies while working alongside some of the country’s leading engineering consultancies
On this project, M&D Construction Group’s Contracts Manager, Niekie Wagener, and Construction Manager, Juan Venter, are working with representatives from Afri-Infra Group, which undertook the design of the water tower and is now supervising the construction works on behalf of Johannesburg Water. They include Project Engineer, AD Watts; Design Engineers, Krynauw Coomans and Francois Cronje; as well as Senior Resident Engineer, Oloff Berh, and Junior Engineer, Jason Boone.
Valued at R31-million including VAT, the main structure comprises the 268m² foundations, which have a pressure of about 150kPA; tower; and tank, including the floor, walls and roof. The secondary elements comprise the steel staircase; cantilevered concrete slab landings; access manhole; and roof structure, including the columns and beams.
Notably, M&D Construction Group and Motla Project will achieve practical completion well ahead of the scheduled deadline in November 2019 and the entire project concluded within budget.
Wagener attributes the excellent performance of the contractor on yet another water-related project to excellent team dynamics between all representatives of the professional team, including sub-contractors and supply-chain partners.
“Certainly, the JV also benefited immensely from the knowledge of our scaffolding and formwork supplier, PERI. The company’s Technical Director, Uwe Meyer, and his team enabled us to devise unique solutions to overcome an array of complexities. Combined with our unique building methodologies, innovative scaffolding and formwork solutions have enabled us to achieve an impressive 30% saving in construction time on this contract,” Wagener says.
A case in point is the use of novel internal and external climbing platforms with circular plywood panels to accelerate the construction of the core of the shaft in an extremely confined area. This is opposed to using a conventional scaffolding tower and formwork that would have restricted space for laydown areas on site and access to the inside of the shaft, while also stifling the general movement of resources around the structure.
It also enabled the contracting teams to access the base of the shaft of the tower to commence working on the ancillary works well ahead of schedule after the first lift had been completed.
Moreover, the same platforms were used to assist with the installation of the main working stages for the cone after six 3,85m pours were completed. Installed at ground level, they were also easily installed by the contractor using a crane.
Working with PERI’s Design Engineers, Werner Beyers and Johan van Dyk, the contracting JV and engineering teams also devised a novel means of safely constructing the tower’s conical-shaped tank 23m above ground level.
Venter says that the system is based on the formwork and scaffolding specialist’s SB Brace Frame system, which transfers the pressure of fresh concrete into the sub-structure and foundations during single-sided concreting of structural elements.
“It was used as a horizontal working platform that was mainly supported by the shaft of the tower. Accessed by our workers via a modular and light stair tower scaffold system and spanning 8,75m from the shaft, the 370m² working platform provided a clear and safe working area for the workers,” Venter says.
The large platform also simplified and facilitated quick assembly of the shuttering for the in-situ cone.
A unique system comprising radiused tubes and tension rings was also designed specifically for this aspect of the works programme to contain the lateral loads of the inclined walls.
This secure “self-balancing” system holds the concrete without the need for propping. Believed to be the first of its kind to be deployed on a circular structure in South Africa, it comprises many custom designed and manufactured components that are now part of the scaffolding and formwork supplier’s stock for future projects.
The work scope also includes the construction of a R10,1-million pump station and interconnecting piping, valued at R2,5-million, in addition to the R4,5-million that Johannesburg Water has invested into sub-contracting work on this project.
When M&D Construction Group and Motla Projects have completed the project, the JV will have used an impressive 2600 m2 of formwork, 90t of reinforcement and 895 m³ of concrete. This is in addition to the 600 m³ of excavations it has undertaken for this project.
Notably, the JV has also maintained an impeccable safety track record on site, with M&D Construction Group’s Macdonald Sedimo receiving an award from Johannesburg Water for his outstanding performance as a Safety Health & Environment Officer.
Certainly, the many employment and skills development opportunities that were created right from the outset of the construction project for many members of surrounding communities is one of the major highlights of this project for Patricia Motla, Managing Director of Motla Projects.
Motla says, “This again demonstrates Johannesburg Water’s firm commitment to driving transformation in the South African construction sector as one of the country’s leading municipal entities. The rapid growth of both Motla Projects and our strategic partner, M&D Construction Group, demonstrates the success of government’s pledge to developing an inclusive and diverse South African construction industry.”
Rukesh Raghubir, Chief Executive Officer of M&D Construction Group, also lauds Johannesburg Water Project Engineer, Nthabiseng Seopela, and Tshililo Ramugondo, Project Inspector, for the role that they have played in creating an environment that encourages out-of-box thinking to overcome challenges.
“We are proud of to be associated with this municipal entity, which is responsible for supplying 1,4-million domestic, commercial and industrial customers in Johannesburg. Supplying about 1 542ML of water a day and treating 880ML of sewage a day, Johannesburg Water is the custodian of 128 water reservoirs and towers; 37 water pump stations; 10 depots; 12 069km of water distribution pipes; 11 621km of wastewater networks; 38 sewer pump stations; and six wastewater treatment works,” Raghubir concludes.