IRN NOVEMBER-DECEMBER 2013
47
SITE VISIT GROUNDFORCE
time required to install a steel frame solution.”
There are other benefits. “For safety it is much
better”, he continues, “The tower crane operator
doesn’t have to think as much as with the steel frame.
And for the client, [there is a cost saving because]
we don’t need to use vertical support beams for a
steel frame, and don’t need reinforcement of the
concrete base slab.”
Installing and managing the struts has been
straightforward. “We are used to hydraulics”, says
Mr Binétruy, “so it has not been so difficult.” (The
only minor issue has been the level of the second
basement slab, which will require Implenia to raise
the lower set of struts before the concrete is poured.)
Groundforce has installed strain gauges in the two
struts adjacent to where the tower crane is sitting,
which represents the ‘worst case’ loading.
Implenia engineers have hand-held gauges,
supplied by Groundforce, that show the strut
loadings in real time. The lower struts are measuring
up to 90 t loads, including a 20 t ‘thermal’ load
during hot weather when the steel expands. The
upper struts, which connect directly to the capping
beam on the concrete wall, are taking a basic design
load of around 40 t. The struts are deforming by
around 8 cm downwards due to the loadings, which
is well inside the design limit of 12 cm.
Amsterdam-based Peter Richardson, an
experienced piling and foundations engineer who is
acting as a consultant to Groundforce in Europe, says
the project is an important one; “It is an opening to a
completely new market, with the biggest contractor
¬
On the upper layer the struts tie into the capping beam; on the
lower layer they connect to a temporary beam.
Jean-Pierre Binétruy, project manager at Implenia’s foundations
division.
the drainage solution!
U
Vacuum prime pumps up to 12”
U
Dry-prime pumps up to 6”
U
Silenced canopies
U
Submersible pumps up to 8”
Open impeller
centrifugal pumps
with hinge set
