Design of footbridges subjected to dynamic loading

Sammanfattning: Modern design of steel pedestrian bridges often results in relatively light constructions with low natural frequencies were there is a considerable risk of resonance to occur from loads due to pedestrians. To resolve the problem a common solution is to increase dimensions of load bearing elements, resulting in greatly oversized elements with increasing costs and have substantial environmental impact. In this rapport it is concluded that oversized dimensions of primary load bearing elements can be avoided with regard to dynamic requirements by implementing a detailed FE-model to evaluate the dynamic response. This conclusion is found from modeling an existing bridge were the FE-model was calibrated to measurements of the constructed bridge in order to create a realistic model. The dynamic response was evaluated according to SETRA and compared to the outcome when reducing the size of load bearing elements, both models also fulfilling the dynamic requirements according to Eurocode. The effect of individual parameters in the FE-model on the dynamic response is also investigated to provide guidelines on how to build an accurate model.