Preserving our cultural heritage: rehabilitation of the Church Street Bridge

The Church Street Bridge is an 85 year old elegant three span reinforced concrete arch structure spanning over the Yarra River and CityLink (Monash freeway) in Melbourne. The bridge is on an important arterial route connecting the inner municipalities of Yarra and Stonnington and carries vehicular traffic, trams, pedestrians, cyclists and extensive services. In 1998 the northern span was modified to increase the height clearance over CityLink. The bridge was granted heritage status by Heritage Victoria in 2001. Following the granting of heritage status to the bridge in 2001 and the reclassification of Church and Chapel Streets from local roads to an arterial road in 2004, VicRoads assumed responsibility for the maintenance of the bridge and is currently undertaking extensive rehabilitation works. A number of major investigations have been undertaken to determine the nature and extent of deterioration in the bridge and this paper outlines their findings. These investigations have established that the bridge is characterized by concrete of low compressive strength, high porosity and permeability and is significantly carbonated in all areas of the bridge structure, leading to corrosion in the reinforcement and associated significant spalling and cracking of the concrete. The paper provides details of the remedial options considered and the rehabilitation methodology adopted which includes conventional concrete patch and crack repairs, the application of a high performance protective coating and waterproofing of the bridge deck. The works had to be planned to accommodate stringent project requirements in regards to public safety, heritage requirements, impact on traffic and environmental constraints. Works commenced in 2005 and are scheduled to be completed in August 2011. The paper also provides an overview of progress to date.