Enerpac OHT crane begins at Reunion

Work has started with Enerpac's world record 4,800 tonne capacity offshore overhead travelling crane to build the offshore highway at Reunion Island in the Indian Ocean.

A 5,400 metre bridge is being built for the new highway on the island east of Madagascar by French consortium Bouygues Travaux Publics, VINCI Construction Grands Projets, Dodin Campenon Bernard and Demathieu Bard Construction.

The highway, called the Route du Littoral, will connect Saint Denis - the administrative capital of La Réunion - with La Possession. It replaces the existing coastal road, which is exposed to falling rocks and flooding from swells and tropical storms.

The Enerpac overhead travel crane (OHTC) used in this project comprises two pairs of lifting beams, with an overall width of 30 m, and a lifting capacity of 4,800 tonnes for lifting, moving and lowering the concrete blocks for the offshore highway. The crane is classified as A5 for the structure classification and M5 for the mechanism. It is designed to operate in tropical marine conditions. Design and testing conforms to Bureau Veritas code for offshore units.

Lifting and lowering is accomplished with a reeved winch system based on eight grooved drum winches. Longitudinal travelling of the gantry uses a trolley arrangement comprising two trolleys per lifting beam. Each trolley is propelled with hydraulic drive motors and planetary gearboxes. The wheels run on two parallel rails bolted onto the barge’s runway beams. Side shifting of the gantry hoists in a continuous movement is achieved using long stroke cylinders.

OHTC testing has been conducted on one of the pairs of beams and included lifting 1,100Te blocks, synchronised lifting of the block with a hook from each beam, and checking the crane’s positioning, lifting / lowering accuracy to 1 millimetre.