Enerpac’s strand jacking system was used to hoist and position 135 tonne concrete girders at a bridge project above a deep gorge in Hawaii.
The Enerpac strand lift technology was put to use during the construction of the Kealakaha Stream Bridge when the general contractor, Hawaiian Dredging Construction, was faced with the challenge of placing precast concrete girders more than 60 metres long across a gorge more than 60 metres deep.
According to Enerpac, the strand lift system is capable of safely positioning huge loads to accuracies within fractions of a millimetre. Strand lifting is one of the heavy lifting solutions deployed in Australia by Enerpac Integrated Solutions for tasks ranging from bridge lifting to positioning of huge infrastructure. Using PLC controlled-synchronised lifting, it can handle loads of up to 17,000 tonnes precisely and safety.
Hawaiian Dredging project superintendent Glenn Koki said this was the first time in Hawaii that concrete girders were used for such a long span. There were six girders, each about 64 metres long and weighing 135 tonnes each.
In order to utilise the strand jacks, lifting towers were erected at each end-point of the girder to be placed. The width of the lifting towers was just sufficient for placing one girder, and then the towers were moved to the next placing position.
“Because the multiple jacks can be moved in unison and with great precision, heavy structures can be assembled at ground level (with increased safety and reduced cost) and then lifted into position, rather than having to be built in the air,” Enerpac Integrated Solutions Australasia manager Colin Chapman, said.