Transit New Zealand regional offices and selected local authorities were asked for information from their records on age and proximity to the coast of their bridges. Together they maintain more than 10,500 bridges with concrete superstructures on New Zealand roads. They also completed a questionnaire to identify common durability problems on concrete bridges, and to identify ways that would enable the bridge asset to be more effectively managed.
Responses showed that most concrete bridges are in acceptable condition. Deck joint deterioration is the most common maintenance problem, and affects bridges of all ages. Reinforcement corrosion is more common on older bridges and on those near the coast. Current standard concrete construction specifications ensure at least a 50-year service life if they are followed during design and construction. A national bridge management system would provide a cost-effective means of managing information on bridge condition, location and construction details.
Keywords: Bridges, concrete, durability, New Zealand, roads, state highways