Company Announcement - Gauteng Piling had to install 175 auger cast-in-situ piles of unusually varied diameters for the foundation of a new upmarket apartment block in Hatfield, Pretoria, earmarked as accommodation for students at the University of Pretoria. Studios @ Burnett, the multi-storey apartment block is being developed by the Feenstra Group and Costa Zervas Projects. The new development is on a 4 300 square metres site on the corner of Burnett and Grosvenor streets, Hatfield, close to the university.

The auger piles provided by Gauteng Piling are formed by drilling holes into the ground, placing steel reinforcement into the holes, then filling the holes with concrete. In built-up residential areas, such as Hatfield, the drilling for auger cast piles cause minimal disturbance.

Kobus Geyer, Site Manager for Gauteng Piling for the project, says the 175 auger piles required for the foundations were exceptionally varied in diameter. “For example, we had to provide one 300mm pile, 27 of 550mm, 31 of 800mm, 15 of 1,4m and nine of 1,5m - to name just a few of the 15 different diameter piles specified. The rebar cages inserted into the piles consequently were also extremely varied in diameter: from 150mm to 1,35m. The average depth of the piles was 10m and the vertical loadings ranged between 200kN.m to 9 200kN.m. Gauteng Piling used two rigs for the piling excavations: a Williams LDH digger with 5,5t-m torque, and - for maximum speed - a Soilmec SR30 hydraulic drilling rig on tracks, fitted with high-tech computerised controls,” Geyer stated.

Steel reinforcement employed for the piles ranged from 4 high tensile strength steel rods, with 12mm diameter (4Y12), to 13 high tensile strength rods with 32mm diameter (13Y32). The spirals of mild steel were 8mm in diameter with a 200mm pitch.  The main contractor for Studios @ Burnett is Tri-Star; the architects, Boogertman + Partners; the quantity surveyors, Del QS; the civil and structural engineers, DG Consulting Engineers; and the groundwork contractors, Pentagon.

Gauteng Piling has in the past 18 years completed over 1 500 projects to become one of the major players in the piling industry in Gauteng. The company – which provided the piling foundations for the massive Mall of Africa last year - now has a fleet of 20 auger drilling machines, two cranes, two bore rigs, four Grundo hammers, and two lateral support machines.