Five Islands Road Bridges - Piles
Speers Point, Lake Macquarie

Five Islands Road is a critical road transport link between the western shores of Lake Macquarie and Greater Newcastle. This project involved duplication to dual carriageway of Five Islands Road from two to four lanes.

The presence of soft soils, potential acid sulphate soils (PASS) and contaminated wastes from a nearby smelter contributed to the problems to be solved on this project. Construction of two new 176m eight span precast bridges over Cockle Creek were required. Each bridge pier is supported on eight 600x 600 square precast composite piles driven to a depth of 14m. SCI, located just 1 km from the site manufactured all 114 composite piles in its nearby factory at Teralba.

SCI designed a concrete mix with compaction and curing procedures that exceeded the stringent RTA concrete specification (B80 for Exposure Classification C). The mix contained 30% fast reacting pozzolans with a water/ cement ratio of 0.31 and 56 day shrinkage of 430 microstrain. A controlled steam curing procedure was also developed that measured and limited the concrete temperature during curing to 65 Deg.C.