LGH Winches installs gantry on truck bed8 December 2004
A £6m ($11m) project to increase the safety of the Mersey River tunnel in Liverpool, UK required subcontractor LGH Winches to install a gantry on a truck bed. The project builds in additional escape facilities and refuge chambers under the deck of the four-lane single-bore road tunnel. Because the tunnel is in constant use, the project needed storage space for materials.
The only way in to this space is through a 2m-square access cover in the middle of the four-lane tunnel. To minimise disruption to travellers, access is limited to one week a month from 8pm to 6am when two lanes of traffic are closed.
LGH Winches designed and fabricated a 3t single-beam gantry that can be fitted onto a flat bed, and can be taken off as well. The lifting frame lowered the materials through the access hole to a storage area 5m below the deck. The frame was also safer than a jib crane that risks slewing into oncoming traffic, the company said.
In conjunction with main project contractor Amco Donelon, LGH Winches also designed a storage and transfer system comprising two 80m long beams supported at 4m intervals by 20 columns of heights that varied to accommodate a tunnel incline of 1:30. A single-girder trolley holding a 3t hoist runs along these rails. To lift the steel beams in place, the company lowered a mini-crawler crane. The gantry was ready in three weeks, it said.