The influence of railway vehicle modeling approach on the dynamic response of a bridge span

The paper presents the results of numerical analysis and in-situ measurements of two railway bridge spans subjected to an action of moving vehicles. The railway vehicle is introduced using four simplified load models: series of concentrated forces, series of lumped masses and series of single-mass and two-mass oscillators. Numerical simulations are performed using FE method. The dynamic parameters of the vehicle and the bridge models are determined on the basis of modal identification results of existing structures – EN57 traction unit and steel bridges of 10 and 30 m theoretical span length. The vertical displacements and accelerations of the mid-span are analysed. The numerical results are referred to the results of in-situ measurements performed under operating conditions. A qualitative and quantitative comparison is made for all load models and bridge spans under analysis in the forced vibration range.