The Civil Engineering Contractor June 2019 | Page 22

ON SITE
Safety and precision always first.
Transforming ‘ordinary’
edifice into an
architectural landmark
By Eamonn Ryan
A 26m-long, highly unusual
concrete portico over the
entrance of the Council
for Geosciences head
office, located in Silverton,
Pretoria, transforms what
was a fairly ordinary
looking building into an
architectural milestone.
20 | CEC June 2019
The R3-million GeoSciences project
entails R1.6-million of formwork,
just 70m 3 of concrete and a substantial
15t to 18t of steel. The project was a
tremendous learning curve for all
involved – sadly, as a once-off these
lessons may take a long time before
they are needed again.
Architect Pieter Breytenbach,
of Deter Architects & Designers,
was given free imaginative rein on
the concrete portico cover over
the entrance. “It was a fairly old
building, so it was a challenge to get
a structure which would relate to the
existing building while contributing
something to its aesthetics. To achieve
that I employed one of the oldest
structures ever designed – the arch.”
Making it especially challenging
was the fact that the ground ramped
up towards the entrance, so the design
had to accommodate the gradient
slope up to the building plinth. In
fact, it was his unique design which
ultimately won him what was an
open tender. The only guidance he
was given, he says, is “they said they
wanted something ‘impressive’.”
“I like working with monolithic
structures and with concrete, in
terms of not adding too much to
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