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8
Mechanical Technology — January 2015
⎪
Special report
⎪
S
uch was the quality of the steel
structure at the Malapa fossil
excavation site, which was the
overall winner and winner of
the Association of Steel Tube and Pipe
Manufacturers of South Africa’s Tubular
category, that Steel Awards 2014 con-
venor, Spencer Erling was prompted to
say: “It is surely the first time since I
have been managing the Steel Awards
process – this year is number 13 – that
the overall winner has ticked so many
boxes as to why this project represents
excellence in the use of steel.”
In 2008, Professor Lee Berger of the
University of Witwatersrand was using
Google Earth to look for possible fossil
deposits in the Cradle of Humankind.
What caught his eye was a nearly
circular ring of trees, something that
indicates a possible cave entrance or
potential fossil deposit. The rest is
paleontological history.
The brief for the Malapa fossil ex-
cavation site was to build a removable
structure over the dig site to protect the
site and the exposed fossils from the
extremes of the weather and to allow for
as much ‘dig time’ as possible. It had
to also blend in with the ring of trees
and the rest of the bush on the hillside
The structure had to, in addition,
have a tourist-viewing platform, a
crawl hoisting structure to lift rocks
weighing up to one ton, and maximum
possible natural light had to be able to
penetrate into the covered area. The
access walkway to the viewing platform
had to be like ‘a blanket over a baby’
so as not hinder the movement of the
natural wildlife – hence no handrails
were permitted.
The final shape when viewed from
above is like a beetle with eight legs. But
how can a structure be designed when
one does not know where the founda-
tions will be? Enter Peter Fellows, the
engineer. It was decided that during
construction, once positions were cho-
sen, rods would be drilled into rocks
around the site, onto which base plates
would be welded. This required that the
eight support columns be adjustable to
suit the plate positions identified.
The roof was to be ‘rondavel-like’ in
shape but not necessarily round, from
which would hang the viewing platform
and hoisting structure.
The detailing and fabrication of a
tubular structure such as this require
special skills, which were provided by
teams from Spiral Engineering, one of
the few companies in South Africa with
the capacity to build such complicated
structures.
To accommodate the site location –
with a 7.5 km farm track access road
that runs through a riverbed – special
trucks with limited capacity were used
on the farm. After four unsuccessful
tries, a 30-ton all-terrain crane with
a long enough radius and capacity to
In this special report,
MechTech
summarises the steel construction project
winners from last year’s Steel Awards 2014, hosted by the Southern African
Institute of Steel Construction (SAISC).
Excellence in the use of steel
access the structure without damaging
the trees and the bush, reached the site.
The judges concluded that the deter-
mination of the whole team, the quality
of their work, the fact that when you
visit the site the roof is not visible from
more than a few metres away, and that
the construction team left the site virtu-
ally as they found it, made this project
“excellent in the use of steel” for every
possible reason.
Category winners
No. 1 Silo, part of the first phase in
the Silo precinct development of The
V&A Waterfront, won the Architectural
category. This 10-storey development
consists of an east and west wing built
on two levels of a mega-basement cov-
ering the whole site.
Structural steelwork was the solu-
tion to provide slender support to the
facades, walkways, bridges, lifts and
feature stairs, while economically
extending the cantilevers of the con-
ventional post-tensioned slabs framing
the atrium.
The roof of the atrium is positioned
above an open volume area spanning
17 metres. A composite steel and con-
crete Bondek slab was designed to serve
as the primary support and waterproof-
ing line to an accessible and functional
roof. Another critical design element of
the atrium was the feature staircase that
served the five office levels.
Heritage requirements regarding the
treatment, restoration and reinstate-
ment of the existing structures were of
the utmost importance and underpin-
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