Design Performance Requirements for Railway Bridges in BS EN 1990:2002 Annex A2

BS EN 1990 Annex A2 contains the design performance requirements that are applicable to railway bridges. Compliance with the requirements limiting deformations and deck accelerations is intended to ensure the safe operation of the railway and comfort of passengers.

While limiting deformations is required for railway bridge design to BS 5400-2 and associated railway group standards, checking the bridge behaviour for the dynamic effects of railway traffic has historically been limited to applying a dynamic factor _ to the static load obtained from the design load models (RU and SW/0) in BS 5400-2. However, where bridge decks fall outside of the limits assumed in determining _, a dynamic analysis is required to ensure that the deformation and vibration limits set in Annex A2 of BS EN 1990 are met.

The background to the differences between the design performance requirements adopted for designs to BS 5400-2 and the requirements of BS EN 1990 Annex 2 and BS EN 1991-2, will be examined. The emerging requirements for clarification and amendment of the design performance requirements in Annex A2 of BS EN 1990 will also be highlighted.