The Civil Engineering Contractor January 2019 | Page 34

PROFILE
Klassen was one of a team, he says,
as this was a complex multidisciplinary
project involving structural engineers,
geotechnical engineers, wind experts,
and architects. The primary concerns
were safety (strength, stability,
robustness), serviceability, economy,
constructability, aesthetics, and low
maintenance.
The project was envisaged as a
community-focused
initiative
incorporating sustainable best
practices such as local labour and
design approaches intended to
minimise future maintenance needs.
While the project has achieved the
original design goals, there were
many challenges.
Tragedy struck in the early stages
of the project, when the temporary
works over the M1 collapsed with
two fatalities. While the temporary
works were not part of the
overall responsibility under Royal
HaskoningDHV, clearly it had a
significant impact on delivery.
“The collapse of the temporary
works during construction had a
significant effect on the completion
of the project. It was important to
respect those who lost their lives
and were injured. In addition, the
investigation into the accident needed
to be carried out thoroughly. Although
contractually the completion date was
not met due to the reasons mentioned
above, the permanent bridge reached
practical completion on 16 March
2018, which generally met the client’s
expectations,” says Klassen.
Project specs
The completed bridge has eight spans
with a continuous post-tensioned
concrete box girder deck. The main
span over the M1 freeway is supported
along its centreline by cable stays. The
cables are supported by a concrete
pylon with a height of 54m above
deck level. The pylon was supported
by backstay cables anchored into the
more opportunities to enhance the
aesthetic flair of the bridge.”
Building Information Modelling
(BIM) was used for the design and
drafting of the bridge. Design is likely
to become even more exciting in the
near future as BIM develops. Klassen
says: “BIM is really starting to take
off in the transportation sector —
although it has been around for a
while in building infrastructure. In
fact, 3D design/drafting programs
like Civil 3D and Revit are now being
used to communicate transportation
designs and not just rely on 2D
drawings. In five years, BIM/3D
designs, visualisations, and virtual
reality presentations will become
mandatory by our clients. The rapid
change of technology, 3D design,
automation, and parametric design
are already on our doorstep. New
civil engineering graduates will not
only need to be a civil engineer but
also be a computer programmer to
have a real edge in the future.”
Night view of the Grayston Pedestrian Bridge.
32 | CEC January 2019
www.civilsonline.co.za