Replacing the piers of an existing continuous box girder bridge with portal structures

The Princes Highway outbound ramp is a 170 m long, five span bridge over the West Gate Freeway in Altona, Melbourne. As part of the West Gate Tunnel Project, at-grade realignment of the interchange configuration required replacement of two of the existing piers with portal structures. The five-span superstructure comprises continuous precast concrete box girder segments which were post-tensioned in a staged construction procedure. The two existing piers were removed and replaced with portal structures spanning over the realigned interchange lane configuration. The portals consisted of a fabricated steel box-section crosshead which is simply supported on precast concrete columns. The project specific requirements required that the works did not reduce the capacity of the retained elements. Therefore, a load rating of the existing structure was undertaken to determine its current ability to withstand imposed loads. A load rating of the superstructure and substructure in the modified condition, following the replacement of the pier structures, was also undertaken and compared to the load rating from the original condition. The replacement of a column support with a portal frame structure led to an overall reduction in vertical stiffness of the support. In order to account for the reduced stiffness of the portals, the replacement pot bearings were installed at an initial upwards displacement under self-weight, to manage the modified load distribution throughout the continuous superstructure. This paper will present an overview of the key design and construction challenges and lessons learnt for the implementation of these works.

• Record URL:
  • https://austroads.com.au/publications/bridges/abc2022-000-22
• Record URL:
  • https://arrbknowledge.com
• Authors:
  • Rafferty, J
  • Bowen, W
• Conference:
  • Austroads Bridge Conference, 11th, 2022, Adelaide, South Australia, Australia
• Publication Date: 2022-11

Media Info

• Pagination: 17p
• Monograph Title: 11th Austroads Bridge Conference, Adelaide, 15th-18th November 2022

Subject/Index Terms

• TRT Terms: Access roads; Box girders; Bridge management systems; Bridge piers; Bridge superstructures; Bridges; Interchanges; Loads; Maintenance
• Geographic Terms: Australia; Melbourne, Victoria
• ATRI Terms: Access road; Box girder; Bridge maintenance; Bridge pier; Bridge superstructure; Interchange; Load
• ITRD Terms: 3473: Superstructure (bridge)
• Subject Areas: Bridges and other structures; Maintenance and Preservation; I61: Equipment and Maintenance Methods;

Filing Info

• Accession Number: 01901698
• Record Type: Publication
• Source Agency: ARRB Group Limited
• Files: ITRD, ATRI
• Created Date: Dec 7 2023 2:54PM