Design of supporting beams to replace undermined bridge abutments, Cross City Tunnel Project – Cowper Wharf Road

The Cross City tunnel works included the provision of a new exit lane from Sir John Young Crescent into the Domain Tunnel. This location is a complex system of three bridges in a tightly constrained three tiered roadway. To provide the additional traffic lanes required an increased width under the Art Gallery Road Bridge (AGRB), Eastern Distributor / Macquarie Street (ED/MS) exit ramp bridge and the Cowper Wharf Road (CWR) Bridge abutment. At the CWR and ED/MS exit ramp bridges, new prestressed concrete structures were built behind the abutments to be undermined and stressed against the existing abutments. The rock underneath the existing abutment was then excavated in sections. The AGRB is a portal frame bridge comprising a post-tensioned box superstructure and inclined reinforced concrete buttress abutments. New reinforced concrete columns (south abutment) were constructed each side of the existing buttresses, stressed against the existing structure and jacked up in order to transfer load from the existing abutment to the new structure. These innovative construction techniques covering an 18-month period ensured the existing structures were effectively supported prior to removal of their original support material, without disruption to traffic. (a) For the covering entry of this conference, please see ITRD abstract no. E214936.


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  • Accession Number: 01051081
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ITRD
  • Created Date: Jun 11 2007 1:19PM