The Water and Sanitation Department of the Ekurhuleni Metropolitan Municipality has deployed advanced technology on a reservoir construction project while ensuring that ample employment and development opportunities have been created for members of surrounding communities.
Tango’s Consultants is overseeing the construction of the 25Ml reservoir in Pam Brink, Springs, while working alongside principal contractor, Anita Building.
This leading firm of consulting engineers also participated in the design of the new reservoir, which is being constructed adjacent to an existing 11,4Ml reservoir to bolster water supply to this rapidly expanding area of the Ekurhuleni Metropolitan Municipality.
Notably, its roof and wall are being built entirely from prefabricated concrete elements to significantly fast-track the completion of the project.
Using conventional construction methods, only two trades would have been able to work at any given point in time. These include the construction of the wall, a complicated undertaking that demands absolute precision to ensure water-tightness. This slow and meticulous process is followed by the construction of the roof, which entails erecting and installing tons of scaffolding and formwork inside the structure.
In addition to being more cost-effective than cast-in-place methods and safer, the cutting-edge technology facilitates the construction of a higher quality final structure. This is considering that the various elements are being manufactured in a controlled factory setting that is far removed from the many variables encountered on a traditional construction site.
The wall and roof of the reservoir were manufactured at Corestruc’s factory and will also be installed by the leading precast-concrete specialist.
Mojela Thamae is Tango’s Consultants’ junior Resident Engineer (RE) on this project. Thamae, who graduated from Central University of Technology in Bloemfontein, remains extremely proud of the extent of innovation deployed on this construction site.
“It is an extremely efficient process. Up to five months have been saved on the construction programme by constructing the reservoir in this manner, which enables more than one trade to work simultaneously,” he says. “Corestruc will complete a large portion of the wall before the end of the year, following the imminent finalisation of the in-situ floor slab by the principal contractor. This work will be followed by the construction of the in-situ column footings for the roof structure in mid-January. The specialist sub-contractor will commence installing the roof shortly thereafter. This will be followed by the installation of the remaining wall panels and then post tensioning the structure,” Thamae explains.
The precast-concrete wall panels will be dispatched to site and grouted in place on a ring-beam that was constructed before work commenced on the concrete floor slab.
Buttresses are used to reinforce the structure, with both vertical and horizontal tensioning deployed to resist applied forces.
The reservoir is sealed using a special grout that has been designed to reach a compressive strength of 100MPa within four days and further react when it comes into contact with water when the reservoir is being filled. It is pumped through temporary shutters around the circumference of the reservoir in a controlled manner after the installation of kilometres of post-tensioning ducts and cables.
Meanwhile, the roof of the reservoir comprises precast-concrete columns, beams and hollow-core slabs, which are stitched together to create a single monolithic structure.
While the bulk of the reservoir is being constructed in this manner, Tango’s Consulting and Anita Building have ensured that the project creates ample opportunity for employment, as well as skills training and enterprise development for members of surrounding communities. This is in line with the policies of the Ekurhuleni District Municipality on all its infrastructure projects.
“While engineering is constantly evolving to deliver world-class infrastructure faster and more cost-effectively, South Africa has unique socio-economic challenges that also have to be considered. Right from the outset, we knew that we had to achieve a perfect balance between using advanced technology with all its associated advantages and ensuring that this project benefits as many community members during the construction phase,” Thamae says.
To this end, 33 black-owned subcontractors each employing three community members will work on this project once it peaks next year, with significant emphasis having also been placed on recruiting unemployed youth and women from the community.
The subcontractors are being trained and supervised by Anita Building, which engaged with relevant community representatives well ahead of the company mobilising to site.
Melvin Mbero, Construction Manager of Anita Building, says, “This approach ensured that we were able to establish a sound rapport with the community members early on. They have been tasked with, among other aspects of the works programme, site preparation and earthworks, paving, backfilling, and landscaping. This is in addition to the construction of the chambers of the reservoirs and the pump-station building. These less onerous aspects of the works programme have provided ample opportunity for skills, as well as enterprise development and training.”
These opportunities are complemented by the long-term jobs that have been created at Corestruc’s factories. The company employs people with specialist skills and experience who work on numerous reservoir projects simultaneously. This includes a 30Ml reservoir for the same municipality in Selcourt, Springs.
Notably, Corestruc will have assisted municipalities and their professional teams to deliver more than 140ML of water-storage capacity by mid-2021, despite the impact of the Covid-19 lockdown period on most construction projects in the country.
“Certainly, Corestruc is very proud of the role that we are playing in helping municipalities significantly fast-track the construction of water infrastructure in the country. This is in addition to assisting with the roll-out of projects that are creating many opportunities for training, as well as skills and enterprise development during the construction phases,” Willie de Jager, Managing Director of Corestruc, concludes.