PILES OF WORK Gauteng Piling has completed nearly 1 500 major piling contracts
Despite being hampered by water ingress after heavy summer rainfall, piling company and Master Builders Association (MBA) North member Gauteng Piling completed its piling contract for a new large-scale warehouse for Value Logistics in Pomona, Kempton Park, in March.
The company conducted extensive prepiling geotechnical soil tests and was prepared for a relatively high level of moisture in the soil; however, none of the preliminary soil tests could predict the heavy summer rains that followed, which subsequently resulted in the water table rising much higher than expected.
Gauteng Piling contracts man- ager Martin Eygelaar explains that, to deal with the moisture levels and water ingress into the drilled holes, the company used the traditional drill-and-cast piling method instead of the auger-piling method, as the pile bore could not be sealed against water ingress.
“Drill-and-cast operations require a concrete-mixing truck to be on standby next to the drill rig so that, when the rig reaches the required depth, the drill operator can immediately lift the extracted soil to the surface, allowing the concrete to then be cast – within seconds – to prevent water ingress and the piles from collapsing,” Eygelaar explains.
Construction company Bruce Kirchmann Construction was the main contractor on the 9 100 m2 warehouse project, which required 152 auger piles, which are deep foundation elements that are cast in place using diameter flights of 450 mm, 500 mm or 600 mm. The process of installing piles is carried out using auger drills that excavate the piling holes drilled into the soil to predesigned depths, which varied from between 8 m to 10 m for the Value Logistics project.
“After reaching the required depths, the auger hole is cleaned and concrete is placed directly into the hole from the cement truck,” Eygelaar says, adding that reinforcing steel is then lowered into the wet concrete, resulting in the finished foundation element resisting compressive loads.
“The technique has been popular globally and is being used to support towering buildings, tanks, towers and bridges,” he adds.
Site Safety
A major challenge on site was the stringent health and safety standards imposed by the contractors and designers. This involved certifying lifting equipment, providing maintenance records of auger rigs and regularly inspecting the rigs and ensuring compliance with health and safety standards.
“Although far more stringent than what is the norm for most building projects, Gauteng Piling actually welcomed this exceptional emphasis on health and safety as it reinforces our own company’s philosophy. As members of MBA North, we value our staff’s safety above financial profits,” he says.
“In fact, we would like to help the contractors and professional teams lift this project to award-winning status in a future MBA North safety competition,” Eygelaar adds.
Gauteng Piling used two William auger rigs for the Value Logistics warehouse project, an MF-class machine capable of drilling 600-mm-diameter holes and an LDH-class machine capable of drilling holes up to 1 200 mm in diameter. Both mechanical rigs use chains and sprockets.
The rigs provide high drilling speed, which allows sufficient time to place the concrete. They also help minimise the risk of collapse and the ingress of water inside the bore, owing to the flight being evacuated out of the hole faster, thereby reducing the amount of water filling the hole and allowing for the concrete to be poured faster.
Bruce Kirchmann Construction MD Bruce Kirchmann states: “Gauteng Piling has always pro- vided the company with a cost- effective product, delivered professionally and within deadline.”
Company History
Established in 1996, Gauteng Piling, led by MBA North immediate past president Hennie Bester, has completed nearly 1 500 major piling contracts.
The company has attained a 135% broad-based black economic-empowerment recognition and is committed to the future development of emerging contractors in all facets of the building industry.
Gauteng Piling has a fleet of 23 straight-shafted augercast machines, three cranes, four bore rigs and six Grundo hammers (mainly used for residential foundations), as well as three machines for lateral support.
The company recently completed a piling contract for the construction of Southern Africa’s largest single- phase retail centre, Mall of Africa, near Midrand, in Gauteng, which required more than 400 piles.
Other recent contracts handled by the Fourways-based piling company included piling for the Fire & Ice Hotel, The Grove shopping centre and the Bon Accord police station, all in Pretoria.
The company also handled the piling requirements for a new dealership for Chinese auto manufacturer FAW in Croydon, in Ekurhuleni.