Bridges

Durability of post-tensioning tendons is an important backbone for the achievement of the desired service life of prestressed post-tensioned structures. Experience by others, including failures and rehabilitation of major pre-stressed concrete structure elevated the importance of durability of post-tensioning tendons. Acknowledging this issue, Transport for NSW (TfNSW, then RTA and RMS) developed a strategy to address the concern in 2004. Standards, products, and systems that address the durability requirements of post-tensioning tendons, particularly for segmental bridges in aggressive environments were recently developed and adopted by asset owners in the international scene.

This paper will discuss:

• The problem and hazard scenarios of prestressing steel
• Parameters influencing the corrosion of tendons
• Some examples of failures
• Gap analysis of the current TfNSW Technical Direction
• Available avenues for improving quality and performance