Houghton Highway Bridge Duplication

The bridge, the longest in Australia, has seventy-eight 35.3 metre long spans formed from nine tee-roff girders across each span. Each girder weighs in at 80 tonnes. The repetition in spans leant itself to industrial methods of construction and erection.

Key features of Bonacci Infrastructure’s design include:

• A temporary 450 metre long bridge to enable operation of five cranes (150 to 300 tonne capacity) for construction of the permanent bridge. The temporary bridge was constructed from steel piles, steel beams and a precast deck. The temporary bridge was disassembled at the back and re-assembled at the front (leap-frogged) as the main bridge progressed.

• A 160 metre long x 4 metre deep triangulated launched truss to support the upstream leg of the gantry cranes, which were used to install a total of 624 girders. The design included temporary supports on the permanent headstocks.
• Piling frames to enable installation of the 1500 millimetre diameter permanent piles and the 760 millimetre diameter temporary bridge piles.
• Demolition of the old Hornibrook bridge which was constructed in 1930. Demolition was completed with a single 60 tonne crane operating on platforms supported by the old bridge. Three-hundred timber spans at 9 metres long each were demolished, along with their concrete headstocks.
• A new precast facility for 35 metre long tee-roff girders.