Security Aspects of Vertical Actions on Bridge Structure Comparison of Earthquake and Vehicle Induced Dynamical Forces

Modern vehicles are characterised by great load and speed so that their dynamical influence in bridge analysis should be taken into account. During design those loads are usually considered through static analysis and the only dynamic analysis is the one concerning eartquake loading. This paper deals with dynamic equation suitable for taking moving load effecs into analysis and compares them with the vertical earthquake influence as it is considered during the bridge design. Some comparisons of stresses in various bridges have been performed taking into account dynamic load influence, direct support acceleration from ground motion and EC8 regulations. It has been shown that in some examples dynamical load influence produces the greatest stresses in bridge structure and should be taken into consideration.