Rocla meets challenge of supplying four precast bridges

Rocla recently supplied four M-Lock® bridges for Livingstone Shire Council in Central Queensland, with components supplied from as far away as Dubbo in NSW.

Livingstone Shire Council, now part of Rockhampton Regional Council, had identified approximately 70 aged timber bridges which needed replacing in 2004 and called for expressions of interest but did not proceed.

 In September 2006 the council recalled expressions of interest in four of the bridges, subsequently awarding the contract to Brisbane firm Canstruct, based on the use of Rocla M-Lock® precast headstocks and bridge planks.

Rocla’s Brisbane office worked with Canstruct on the initial proposal, which was passed on to Rocla’s Mackay operation for final negotiation. Meanwhile Cardno in Sydney undertook design of the bridges, including changes to the original piling, bridge layout, alignment and kerb arrangement.

All four bridges were designed as two-lane structures utilising precast 8.4m headstocks and abutments, with deck unit spans ranging from 10 to 12m. The Alligator Creek bridge was the largest replacement structure, with five 11m spans.

Canstruct’s approach to the construction of the multiple bridges was to build two bridges simultaneously, in two pairs. The two northern-most structures at Perkins Creek in Marlborough (100km north of Rockhampton) and Banwan Creek on the Stanage Bay Road were undertaken concurrently, beginning in late April 2008.

The remaining two bridges over Alligator Creek in Rossmoya (20km north of Rockhampton) and Belmont Creek in Glendale (northern suburbs of Rockhampton) were also built simultaneously beginning in mid-July. Construction of all four structures was completed in early December 2008.

Canstruct developed and implemented systems which allowed an accelerated construction program despite the limits set by the variety of substructure requirements, from shallow footing systems to driven pile and bored pier foundations, as well as the flood mitigation controls dictating the bridge deck configurations.

These in-house advances in the application of Rocla’s M-Lock® system now allows Canstruct to offer a cost and time effective solution for regional bridge replacement projects.