Lifting challenge on Forth Road Bridge job
By Ian Vallely11 February 2016
UK-based Rope and Sling Specialists provided a below-the-hook solution to infrastructure management company Amey to lift a truck-mounted access platform during overnight repairs on the Forth Road Bridge in Scotland.
Rope and Sling provided a spreader beam lifting rig to lift a 35 tonne Bronto Skylift mobile elevating work platform (MEWP) provided by Nationwide Platforms.
Access was required to make a repair to a support truss on the bridge’s northern pier. The pier from the north tower is sited on the Mackintosh Rock, a whinstone outcrop that made for an ideal foundation during construction.
Rope and Sling hired a modular spreader beam type MOD70H with two MOD34 beams manufactured by Modulift, with various round slings and shackles from its rental stock. The rig was assembled in line with computer-aided design (CAD) drawings of the MEWP sent to Rope and Sling by Nationwide Platforms.
The lifting rig was used below the hook of a barge crane that lifted the truck mounted hydraulic platform onto the barge from the shore, travelled to the site, then lifted it to the base of the bridge from where it would lift personnel, stabilised by outriggers. On completion of the work, the rig was used again to return the MEWP to the barge, remove it from the scene by water and return it to shore.
Steve Hutin, managing director of Rope and Sling Specialists, said, “We only had half a day to design the assembly of the rig and deliver it to the site but we were able to use CAD drawings from Nationwide to calculate the centre of gravity – the load was heavier at one end – and we knew we could use the outriggers as pick up points.”
The main towers of the Forth Road Bridge rise moree than 150 metres above high water level. The bridge has a span of more than 1,000 m between the two main towers and the side spans that carry the deck to the towers are each more than 400 m long.