To complete remedial maintenance works on dual carriageway bridges along one of Australia’s busiest metropolitan road corridors, a Durapac Syncmaster Synchronous Jacking System from Kennards Hire Lift & Shift was used with millimetre precision.
Michael Broome, managing director of Precision Jacking Services, worked with Kennards Hire Lift & Shift to develop the solution.
“The two pot bearings on the north and south bound abutments on each bridge required replacing,” explained Mr Broome.
“To achieve this, the bridge needed to be lifted by 10 mm but kept within a tolerance of 0.5 mm. The Durapac system allows operators to vary the pump speed and adjust the flow rate, which enables a higher level of accuracy during jacking to be achieved.
“When the lift was conducted, a tolerance of 0.14 mm was achieved. This level of precision couldn’t be accomplished with manual jacking systems,” he said.
Durapac RPLC2502 hydraulic pancake cylinders with 250 t capacity and locking collars were used at each jacking point on the abutment. Incorporated as part of the setup, hydraulic hoses and stroke sensor cables were run from the jacking points under the bridge to the Durapac Syncmaster unit and jacking of the structure then commenced.
Initial pressure was induced into the system in order to pre-load the hydraulic cylinders and lifting of the bridge commenced in 1 mm increments. Once lift off was achieved, this was then increased to 2 mm increments until the target height was reached.
Featuring a user-friendly 15 inch full colour touch screen that is scratch and cut resistant, which allows for easy monitoring, the Durapac Syncmaster is ideally suited for use by companies undertaking bridge works and maintenance, bearing replacement, ship loaders, coal reclaimers, lifting and lowering of heavy mining equipment as well as building alignment, centre of gravity determination and structural testing.
“One of the benefits of using it is the unit data logs the entire lift recording both pressure and displacement at each point at one second intervals,” added Mr Broome.