Bridges

Steel became a common construction material for bridges, replacing timber and masonry construction to achieve longer span crossings. These structures are still functioning well, although the majority of them are now considered to have sub-standard capacity in the 21st Century. Steel bridge members and components are commonly affected by chemical agents in exposed air, water, and soil. These chemicals trigger and accelerate the corrosion of steel and the need to have more maintenance and repairs. Vehicles impacting low clearance bridge members can cause momentous damage to these structures.

Steel bridges, particularly those with sub-standard vertical clearance, are regularly impacted by vehicles. This paper will investigate typical damage caused by vehicle impact and discuss examples of repair methods, using three case studies:

• MacRobertson Bridge in Melbourne will be used to examine the damage and repairs to a steel truss
• Damage to bridge girders will be explained using Point Wilson Road Bridge over Princes Highway
• Heritage listed Mia Mia Iron Girder Bridge (The Redesdale Bridge) will be used to explain the need for special care and reinstatement for restoring an historic bridge.