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Sir William Goodman Bridge Restoration 2014

The following information is extracted from a powerpoint presentation by John Woodside, most of it verbatim.

The photographs below show the condition of the worst-affected girder in 2011 after loose and deteriorated concrete had been cleared away. At the time of construction designers provided only a thin layer of concrete 'cover' to the reinforcement, trusting in the high pH value of the cement to protect the steel from corrosion. This proved insufficient, particularly in parts exposed to rain with cycles of wetting and drying. Over the years carbonisation reduced the pH, aggravating the situation. However, the most important cause of corrosion was stray electric currents from the tram rails. The resulting rust forced off the cover, a process known as 'spalling'. (For more, see e.g. Wikipedia on Concrete Degradation.)

Photos: John Wooodside

The responsible Councils, the City of West Torrens and the City of Charles Sturt, authorised a trial repair to check whether remedial work was practicable at reasonable cost.

The trial repair was carried out in February and March 2013. Where there was no corrosion and spalling, the existing concrete was found to be in sound condition and of a satisfactory strength. Where damage had occurred, these areas could be successfully repaired using appropriate concrete repair techniques.

The trial repair demonstrated that the bridge could be restored and strengthened in an economical and effective manner. The work was inspected by officers from both Councils and Heritage SA and met Heritage SA expectations.

The total estimated cost of the works was $2.6 million (including professional fees, trial repairs and $200,000 construction contingency)

The City of West Torrens decided that the best course of action was to relinquish its responsibility for the bridge for 80 years, allowing the City of Charles Sturt to repair and reconstruct the old bridge and accept responsibility for its ongoing maintenance.

The City of West Torrens made a one-off contribution to the cost of reconstruction.

The City of Charles Sturt made a similar contribution to the cost of reconstruction.

The State Government also provided an Open Space Grant of about $1.1 million which provided the balance of the funds to allow the project to proceed

Photo: John Wooodside

The repair process involved the following:

Design was undertaken during September and October 2013 and the restoration and repair work was put out for open tender. Construction started on site on 8 January 2014 and was completed in September 2014.

Photo: John Wooodside