EIC Activities Structural Engineer Matt Hennessy recently delivered a paper for the 11th Australian Small Bridges Conference. The paper discussed the methodology selected for the removal of the Beatrice Bush Bridge at the Rozelle Interchange project and describes the justification for the particular method chosen.
You can read the paper in full here.
Here is the abstract from the paper Matt co-wrote with EIC's Technical Director – Structures, Colin Edmonds.
Abstract
The Rozelle Interchange is a new underground motorway interchange which provides connectivity to the M4-M5 Link Tunnels and the City West Link, and underground bypass of Victoria Road between Iron Cove Bridge and Anzac Bridge.
The Rozelle Interchange also provides a connection to the future Western Harbour Tunnel. As part of the construction of the interchange, several existing structures were required to be removed including the Beatrice Bush Bridge that provided an elevated pedestrian crossing of Victoria Road.
The existing bridge was constructed in 2005 and consists of a four span steel box girder with a non-composite concrete deck and reinforced concrete substructure.
The northern approach consisted of 40.555m span and the southern approach consisted of 17.605m and 30.025m spans. The segment spanning Victoria Road was 40m in length.
The bridge was given a vertical crest to meet the required vehicle envelope of Victoria Road and is horizontally curved in plan to meet the required grade specifications.
The steel girder was integral in configuration and was stressed to each pier and abutment due to fabrication complications during construction.
Due to the location of the bridge, the time allowances for deconstruction were highly constrained and traffic management plans and safety were paramount.
The removal sequence and associated analysis was centered around the planned closures of Victoria Road.
The selected removal sequence was chosen to be an “inside out” approach where the span crossing Victoria Road was removed first and two workfronts removed the remaining three outer spans.
This introduced complications in analysis as it differed from the original sequential construction sequence.
This paper will focus on the selected deconstruction methodology of the bridge and associated staged analysis, studying the effects of girder removal including removal of the prestressing bars tying the girders to the piers and abutments.
It also outlines the key constraints and considerations during the analysis and removal sequence and discusses the resulting deconstruction of the bridge that occurred in 2020.
