London Underground – successful outcome of bridge assessment programme

London Underground (LU) has a large civil engineering asset portfolio of which bridges comprise approximately 8000 assets. The LU system, which was constructed by various private railway companies commencing in the early 1860s, continues to provide service today, with some bridges having therefore been in use for over 150 years. As a variety of railway companies were used for the bridge constructions, diverse designs exist across the LU network. Many record drawings have been destroyed over the years as part of space-saving initiatives and others lost during mergers and takeovers of the various railway companies. Furthermore, in the early 1980s LU lacked formal engineering standards and procedures for the effective asset management of its bridge stock. It was therefore decided to embark upon an assessment project to determine the extent, condition and load-carrying capacity of the company's bridges and structures. This paper will describe how pioneering inspection and assessment standards were devised. It will progress to outline the bridge assessment strategy, the formulation of a risk management system to address non-compliant bridges and how the final assessment results have enabled maintenance and capacity improvement works to be prioritised (Figure 1) to ensure that the LU railway delivers a safe, efficient and reliable service.