Housing in Southern Africa May 2015

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Cement & Concrete
Gauteng Piling had to install
175 auger cast-in-situ piles
of varied diameters for the
foundation of a newapartment block
in Hatfield, Pretoria, which has been
earmarked for students at the Univer-
sity of Pretoria.
Studios @ Burnett, a multi-storey
apartment block, is being developed
by the Feenstra Group and Costa
Zervas Projects. The 4 300m² project
on the corner of Burnett and Grosve-
nor streets, Hatfield, is close to the
university.
The auger piles provided by
Gauteng Piling are formed by drilling
holes into the ground, placing steel
reinforcement and then filling with
concrete. In built-up residential areas
such as Hatfield, the drilling for auger
cast piles causeminimal disturbance.
Kobus Geyer, Site Manager
for Gauteng Piling, says that the
175 auger piles required for the
foundations varied in diameter. “For
example, we provided 1 x 300 mm
pile, 27 x 550 mm, 31 of 800 mm,
15 x 1,4 m and 9 x 1,5 m - 15 different
diameter piles were specified. The
rebar cages inserted into the piles
consequently were also extremely
varied in diameter: from 150 mm to
1,35 m. The average depth of the
piles was 10 m and the vertical load-
ings 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 comput-
erised controls,” Geyer stated.
Steel reinforcement employed for
Student apartments
the piles ranged fromfour high tensile
strength steel rods, with 12mmdiam-
eter (4Y12), to 13 high tensile strength
rods with 32mm diameter (13Y32).
The spirals of mild steel were 8mm in
diameter with a 200 mm pitch.
The team included: the main con-
tractor: Tri-Star; architects, Boogert-
man + Partners; quantity survey-
ors: Del QS; civil and structural
engineers: DG Consulting Engi-
neers; and groundwork contractors:
Pentagon. ■