Assumed loads for the FE simulation
For the computational strength verification and the adequate estimation of the fatigue strength of the aluminium bridge, we must first make some considerations regarding the expected loads. It is not sufficient to examine the bridge structure for its ultimate load alone. Rather, additional loads act on a bridge due to temperature differences in summer and winter, which lead to significant changes in length. Therefore, the FEM calculation of the pedestrian bridge is carried out at low as well as at high temperatures for the required bearing load.
Boundary conditions for the FEM simulation of the bridge
In addition to the ultimate load and the thermal length change, the correct support of the bridge also plays a decisive role for the strength. In practice, it is often observed (e.g. on a motorway bridge) that the end of a bridge is flexibly supported on a steel roller. This allows the bridge to expand or contract accordingly, especially in the longitudinal direction, at different external temperatures.