The West Gate Bridge is undergoing major upgrading and strengthening to give it a new lease of life and enable it to cope with increased traffic demands into the future. This paper describes the work involved, with particular focus on the central 5-span cable stayed steel box girder structure, and touches on the wider lessons for other similar major bridge structures and all those involved with their maintenance and safe operation.

It is nearly 40 years since the tragic collapse during construction on 15th October 1970, and the ramifications of that event still reverberate today. The lessons learnt from that catastrophe and other steel box girder collapses at around that time have had a profound impact on steel bridge design worldwide, and it is important that bridge engineers today are fully aware of the implications so as to avoid any possibility of the same thing happening again.

The West Gate bridge carries an extremely busy 8-lane highway used by 170,000 vehicles a day, and will be widened and strengthened to carry 10 lanes within an extremely challenging timescale and with minimum disruption to existing traffic flows throughout.

The paper describes the assessment and strengthening works, and will illustrate the issues not only from the works in progress on the West Gate Bridge but also drawing on the author's experience with the strengthening of its sister bridges in the UK, namely the Erskine and Wye cable stayed bridges.