West Gate Tunnel - Cable-Stayed Bridge

The structures team at EIC Activities was engaged to provide the construction methodology, bridge erection manual and associated temporary works required to build a pedestrian cable-stayed bridge on the West Gate Tunnel project.

The pedestrian bridge provides a grade separated crossing from the north side of Footscray Road to the southern east side of Waterfront Way.

About the project

CIMIC Group company CPB Contractors was selected by Transurban and the State Government of Victoria as the preferred contractor for the West Gate Tunnel project, in a 50:50 joint venture with John Holland.

The West Gate Tunnel project, one of Victoria’s largest ever urban road projects, delivers a vital alternative to the West Gate Bridge, provides quicker and safer journeys, and removes thousands of trucks from residential streets.

Scope of EIC’s involvement

The EIC team’s involvement included:

• Technical support of the development and optimisation of construction methodology
• Detailed construction staging (not covered in the permanent works design i.e. the bridge erection manual)
• Detailed design of all associated temporary works
• 3D and 4D modelling of the bridge and associated temporary works with clash detection throughout the entire construction phases.
• The team was also engaged to provide engineering support during construction.

Step-by-step instructions

The bridge erection manual covers all stages from lifting pylons onto the substructure to completion of the bridge construction.

This details the construction sequence, expected deflections and stay force adjustments based on staged analysis of the cable-stayed bridge.

The complexity of the cable-stayed bridge construction methodology and temporary works included:

• Asymmetrical one-line semi-fan configuration cable stay arrangement
• Reverse horizontal curve with vertical crest curve alignment
• The nature of the highly sensitive steel box deck structure, where any variation in the loadings and self-weight significantly affects the deck geometry and the global deflections of the girder and the pylon
• Required geometry adjustment with detailed step-by-step construction sequence to align the incoming girder to the previously erected girder using temporary adjustment structures
• Soft ground foundations and associated large settlements
• Temporary supports used to support girder erection prior to splicing, connection to pylon and cable stressing
• Temporary structures, crane lifting operations and locations needed to take into consideration of the existing above and underground services and live traffic operations
• A short closure of the arterial Footscray Road required for the erection of the central spliced girder over Footscray Road.