Up, up and away – bridge removal the easy way
When asked to removed an old footbridge over the main railway line in to Stockport, Manchester, contractor J Murphy & Sons was advised it needed to be done fast and with minimum disruption to the line.
Traditional bridge removal would not have achieved this, and Murphy felt it would be better to lift it up and away. They contacted specialist supplier Lifting Gear UK for a solution.
The solution was a variation on a familiar concept – the C-hook. Commonly used in industry for transporting loads such as coils of steel and other heavy, bulky items, a C-hook wraps around the load, lifting it securely from below. But the type of C-hook required for this job didn’t currently exist.
Luckily, Lifting Gear UK has a subsidiary, Steelwise, that specialises in the production of bespoke steel fabrications – so the design and manufacture of these hooks was easily accomplished.
To lift the bridge, Lifting Gear UK required four C-hooks suspended from the company’s own modular spreader beams. “The challenge for Steelwise was making C-hooks work on a much bigger scale,” says Turner.
Steelwise technical manager Alastair Clark and design engineer Will Almond designed, fabricated and tested the new C-hooks before deploying them on site.
Each hook weighs 3.5 tonnes and is capable of lifting up to 25 tonnes. In order to lift the bridge without inducing any stresses in it, Lifting Gear UK bolted two 26m support beams to the hooks. This provided complete support for the full length of the footbridge, which was pre-tensioned and very fragile.
The lifting operation was completed overnight in May, using an 800-tonne capacity Demag TC2800 lattice-boom crane supplied by Ainscough. Chain blocks were used to link the spreader beams to the C-hooks and provide fine adjustment.