Assessment of steel bridges – cracking the code

This article has been developed from a presentation given at the IStructE conference on 'Structural rehabilitation' in December 2022. It gives a view, based on my career over 30 years, of the way in which our assessment codes can fall short in carrying out a structural assessment of steel bridges. I have taken three differing types of bridge form, scale and purpose, and explained the assessment problems encountered and the method by which a better solution was found using computer methods of analysis. The bridges chosen are the M5 Avonmouth Bridge, a steel box-girder structure; a single-span railway bridge over the River Wey, originally of wrought iron, but subsequently strengthened in steel; and, finally, a lattice-girder truss footbridge. Considering the ongoing pace of development in hardware and software power, and the relative falling cost of computer analysis, the suggestion is made that upcoming assessment codes should make better use of computer tools available.