Bridges

The Gateway WA Perth Airport and Freight Access Project is a major road improvement project to relieve traffic congestion by providing grade-separated interchanges. It includes 11 road bridges, 7 underpasses, 1 footbridge and various other structures of interest. This paper describes the types of structures involved and the more interesting aspects of the structural design. These include the use of bath structures to exclude groundwater from lowered roads in the main free-flow interchange where there were severe height restrictions due to the proximity to major aircraft flight path navigation systems. The project includes extensive use of MSE (mechanically stabilised earth) walls, 7.0 km of noise and screen walls with a high level of urban design, and various types of precast concrete superstructures for bridges with varying architectural treatments and complexities of geometry such as SPUI (single point urban interchange) arrangements. CFA (continuous flight auger) piles were used in top-down construction for one of the SPUI bridges.The project was delivered under an alliance involving Main Roads Western Australia, Leighton Contractors, Georgiou, AECOM, BG&E; and GHD with a high level of co-operation among alliance participants achieved by working in project-oriented teams.