Contractors World UK & Ireland Vol 3 No 6 - page 13

Groundforce takes to
the water at Molesey
On this project, Groundforce Shorco
has supplied its modular Megabrace
frame and MP250 hydraulic struts to
contractors replacing the Molesey Weir
on the River Thames near Hampton
Molesey Weir was built in 1815
and forms one of the longest locks on
the Thames. Joint venture contractor
were installed to support the sides,” explains
Groundforce technical services engineer Oliver
This was done in a pre-specified installa-
tion sequence. First the sheets were driven to
full depth and the ground excavated to 11.6
m AOD where the first Mega Brace frame was
installed. B&V then excavated to 9.25 m AOD,
exposing the existing FST feed pipe, at which
point the second frame was installed.
The third frame was installed at 7.25 m AOD
before the trench was excavated to its maximum
depth of 5.5 m AOD (7 m below ground level),
at which point a 50 mm blinding slab and 400
mm thick concrete pile cap were cast. Once
this had reached sufficient strength, the frames
at levels 2 and 3 were removed to allow space
to install the pipeline.
Such were the lateral forces imposed by the
poor ground that Groundforce had to supply
80 tonne capacity MP80 mechanical struts to
brace the frames.
“The ground was so unstable that we had to
isolate the hydraulic rams and weld the frames
to ensure there was no movement,” says Mr
Page 13
Contractors World - UK & Ireland Vol 3 No 6
Molesey Weir on the River Thames
near Hampton Court.
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