The Civil Engineering Contractor June 2019 | Page 18

ON SITE
A quick redesign resulted in some resulted in some on-site fabrication for the necessary adjustments.
“My guiding philosophy is that we
look past any obstacles to create
solutions for our clients. We have
key staff in place with the necessary
experience and technical expertise to
see such challenging projects through
to successful completion.”
Commenting on the design and
engineering challenges posed by this
project, Schultz explains that, not
being a ground-up structure, the load
of the lower slabs was carried by
pre-existing concrete columns. The
engineer’s specification was that the
load imposed by the new structure
had to be borne by these columns,
and not the existing downstand beams
spanning between the columns.
The project was further
complicated by the fact that one
of the exterior support walls was
thicker than expected, meaning an
unanticipated differential in aligning
the steel and concrete columns.
“This is important because the
engineer ultimately has to sign-off
on the structure, in addition to us
meeting our client’s own exacting
requirements,” Van Gool notes.
16 | CEC June 2019
A quick redesign resulted in
some on-site fabrication for the
necessary adjustments mid-air, as
the trusses were too long. “Due to
the unusual shape of the structure,
comprising
cur ved
tubular
trusses spanning long distances
without column support, which
is usually a feature in much larger
structures like shopping malls,
we had complex geometry to
consider. Hence this was by no
means a slick, bolt-on project, but
a detailed engineering exercise,”
Schultz highlights. The longest
truss fabricated at Fabcon Steel’s
Midvaal factory was 14.5m. spans are vast and you need this kind
of construction to take the loads and
span. In this instance, the design was
partially that, but also for an aesthetic
that was to look quite different. The
engineers were nervous about it and
understanding took quite some time.
We created the jigs for all the trusses
in the factory.
“Once we made the decision to
proceed with this project, the
Logistical challenges airplane wing, as the building
A total of 25t of steel in 18 trusses
and 2 200 bolts were used, which Van
Gool describes as “a lot” considering
much of it is hollow. “For the square
footage, it's higher than one would
normally expect, but we wanted
more trusses.
“What you see here is what you
predominantly only see in shopping
centres and high-volume areas where
“The curved shape was
selected to represent an
is in line with the flight path
from OR Tambo International
Airport, providing a
spectacular vantage point to
view airplanes landing and
taking off.”
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