The world's largest offshore gantry crane has completed testing ahead of being deployed to help build a 5.4km bridge on Reunion Island in the Indian Ocean.
The Over Head Travel Crane (OHTC) has a lifting capacity of 4,800 tonnes for lifting, moving and lowering the concrete blocks for an offshore highway being built by a French consortium on the small island to the east of Madagascar.
The highway is designed to replace the existing coastal road connecting the administrative capital Saint Denis with La Possession, which is exposed to falling rocks and flooding from swells and tropical storms.
Built by Enerpac, a subsidiary of US engineering giant Actuant, the OHTC consists of two pairs of lifting beams, with an overall width of 30m and the crane will be used on a jack-up barge currently under construction in Poland.
The device uses a reeved winch system, based on eight grooved drum winches, to lift and lower the blocks, while two trolleys per lifting beam running along parallel rails bolted onto the barge’s runway beams allow the gantry to travel back and forth. Long stroke cylinders are used to shift the gantry hoists from side to side.
Testing was carried out on one of the pairs of beams at Enerpac's Hengelo manufacturing facility in the Netherlands and included lifting 1100Te blocks, synchronized lifting of the block with a hook from each beam, and checking the crane’s positioning, lifting and lowering accuracy to 1mm.