DMRB CS 457 – The assessment of composite highway bridges and structures

Access free from the DMRB website. Also available from CIS.

This document contains requirements for the assessment of existing steel/concrete composite structures and structural elements.

In the original drafting of BS 5400, important innovations had been made in respect of loading and environmental assumptions, design philosophy, load factors, service stresses and structural analysis, taking into account theoretical and experimental research and several design studies made on components and on complete bridges. In drafting of the assessment version of the Standards, further work of this nature has been undertaken, some of which is relevant only to assessment.

This document allows some differences from the corresponding rules for design, for example:
1) worst credible strength can be used in place of design values;
2) forms of shear connection, strengthening and stiffening, including incidental forms, can be taken into account where their presence is identified; and,
3) it can be accepted to assess some structures on the basis that composite action exists, even though they were not designed as composite structures.