Chapter 5: Bridge Lifetime Data

This chapter considers the lifetime of bridges, the data on age and the various factors affecting it. It uses the useful lifetime, which is the design working life of codes (which assumes no repairs) extended to when the bridge is removed. Lifetime data based on the current age of bridges is taken from a number of sources, together with the time to major repair and demolition. The data is used to establish the key factors determining lifetime. The important factors include materials, structural form, articulation, and ownership. The 200-year-old Menai Bridge is used as an example of lifetime with changing loads and materials and numerous repairs and strengthening over a still continuing useful lifetime. The lifetime data of various materials are noted. The concept of Improving the Lifespan by Design is introduced and the choosing of a design working life recommended. A method of estimating the likely useful lifespan of existing bridges based on probability data and the various influencing factors is outlined. This chapter will assist bridge professionals in addressing the United Nations sustainability goal 9: Industry, innovation and infrastructure.