Abstract
During their service lives, metallic structures are susceptible to degradation through corrosion and fatigue, particularly when loading and environmental demands increase over time. In the UK, as in many other countries, the transport infrastructure network relies on a large number of ageing metallic bridges which require careful performance management under tight budgetary constraints in order to extend their lives for longer than planned, or to overcome deficiencies revealed during operation. Over the past decade, significant progress has been made in understanding many facets of their behaviour, including better appreciation of loading histories and future trends, refined approaches for structural modelling, the potential impact of deterioration processes on performance indicators, and the development of new repair techniques using fibre reinforced composites. Moreover, life cycle considerations have encompassed both economic and environmental criteria. Lessons learned from a variety of projects undertaken in conjunction with infrastructure owners and other stakeholders are reviewed, with attention given to the implications for new construction, whose future will depend on the knowledge that we can transfer successfully from a previous generation of structures.