Project Description

The project involved the construction of a new bridge span, which was badly damaged due to the June 2016 flood.

Hoggs Bridge, on Native Plains Road between Railton and Merseylea, provides an important connection across the Mersey River, and a link for the greater Railton community to the Bass Highway.

Restoring Hoggs Bridge has improved access for primary producers to both sides of the river. It also significantly reduced the length of detours in place for local residents while other bridges nearby which were also damaged during the flood. Landslip and scour holes around bridge structure also had been rectified during the repair ensuring the sound condition of the bridge for many years to come.

One of the construction restraints was the threatened Burrowing Crayfish. Training was completed on site to illuminate any possibility of causing any danger.

Technical Details

The construction of Hogg's Bridge was challenging not only due to time constraints but also due to the nature of the work.

A completely new designed abutment and wing wall was placed before the installation of a new span. High-water levels required the engineering team at BridgePro to install a “container base” dam to place the concrete underwater. While the cobble ground condition wouldn’t let the traditionally driven pile be successful, Down the Hole Hammer was used for the first time in our bridge construction history.

Further to the project, it was found both of the piers suffered intensive scouring, possibly due to the same flood.

A 2.5m height scour hole and 1m undermined the pier foundation wouldn’t allow the bridge to be open for normal traffic even with the new span. BridgePro proposed a solution that involved custom fabric socks made for this scour hole and placed underneath the pier by divers. Once they were in place, high-strength grout was pumped into the sock, creating a solid base around the pier. The problem was found and rectified within a week with great effort by the BPE team.

Relevance to B3, R2 Prequalification Categories

• Complex foundations (DTH drilled) poured underwater (B4)
• Roadworks including embankment preparation for the bridge, pavement reconstruction and widening
• Rock pitching
• Causeway construction involving rock pitching, pavement placement