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October 2015
T
he main building contractor,
BUA Africa Properties con-
tracted Gauteng Piling to pro-
vide 100 auger piles to an average
depth of 13 m, which serves as the
foundation for the Kagiso residential
development in Margaret Avenue,
Kempton Park.
Gauteng Piling Site Manager, Rof-
hiwa Tshivhinda says that the auger
piles covered an area of 3 000m². It
took five weeks to install the piles
after the existing structure had been
demolished and the site cleared.
“A multi-storey building of this
nature, towers over neighbouring
structures and requires exceptionally
strong piling to meet the high struc-
tural bending and horizontal forces.
The specifications included two lift
shafts on either side of the apartment
block would act as shear walls to
stabilise the entire building. Gauteng
Piling used 18 piles underneath the
lift shafts by inserting five additional
micro-piles (eg piles-within-piles) to
support and strengthen the founda-
tions. The micro-piles were drilled
through Cross Hole Sonic Logging
(CHSL) tubes and extended into the
pile cap.
“Exceptionally robust 36 mm
Thread Bar steel rods (TB950) were
then inserted by the overhead crane
into the micro-pile anchors for ad-
ditional stability. Each micro-pile
was inserted to a depth of 6 m below
the pile toe and were grouted at
40Mpa at a final depth of 20 m,” said
Tshivhinda.
All of these relatively voluminous
and intricate components were
housed in specially-designed 13 m
long steel cages, with a diameter of
800 mm and weight of 1.8 tons each.
The tensile strength of these cages
for the lift shaft piles are almost four
times stronger than the steel used
for the rest of the piling cages on the
project. To accommodate the wide
cages, 900 mm diameter piles were
drilled using two Williams diggers.
Prior Gauteng Piling’s contract,
the main contractor commissioned a
Deep foundations for
11-storey residential block
company to handle the geotechnical
investigations. This resulted in four
large diameter auger trial holes being
drilled in a grid pattern, spaced 30
m apart. “The holes were drilled to
refusal on very soft, to soft, basaltic
lava rock and showed that the maxi-
mum depths that could be reached
before refusal were from 9.1 m to
13m. Groundwater was encountered
at a depth of 11 m and therefore
Cement & Concrete
Leading piling contractor, Gauteng Piling, provided intricate and
robust foundation piling for the construction of a new 11-storey 240
unit residential apartment block in Kempton Park’s
Central Business District.
Gauteng Piling had to employ the
drill-and-cast method of piling for the
entire contract.
This form of piling calls for a con-
crete truck on standby next to the
drill rig so that concrete can be cast
immediately after the drilling flights
are extracted to the surface.This pre-
vents water ingress and collapse of
the piles,” said Tshivhinda.
Gauteng Piling, established by
Nico Mass, a leading Master Builders
SA industry stalwart and MBA North
member, will celebrate its 20th anni-
versary next year. Gauteng Piling has
in the past 19 years completed over
1 500 projects and is now one of the
major players in the piling industry.
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