Dynamic behaviour of a short span soil–steel composite bridge for high-speed railways – Field measurements and FE-analysis

• The dynamic response from passing trains at high speed is studied for a short span soil–steel composite bridge.
• Soil material damping properties are estimated through analysis of the field measurements.
• Both 2D and 3D continuum models are compared with the measured response.
• The 3D-model enables estimation of the load distribution, which is found to increase at higher train speeds.
• An effective width to be used in 2D analyses is proposed.

The dynamic response from passing trains at high speed is studied for a short span soil–steel composite bridge. Field measurements have been performed, comprising steel strains, vertical crown displacements and accelerations in the steel and the backfill. Soil material damping properties are estimated through analysis of the field measurements. Approaches for numerical modelling are presented, focusing on the dynamic response from passing trains. Both 2D and 3D continuum models are compared with the measured response. Based on the models, the influence of the Young’s modulus of the backfill on the bridge behaviour is investigated. The 3D-model also enables estimation of the load distribution, which is found to increase at higher train speeds. An effective width to be used in 2D analyses is proposed. A dynamic design check using the high-speed train load models in the Eurocode is presented, that for the studied bridge envisage a resonance peak at about 320 km/h.