In this paper, the dynamic response of bridge girders with elastic bearings to moving train loads is studied using an analytical approach. Such a problem hàs not been very well investigated in the literature. The present results indicate that the dynamic response of the beam at resonance remains generally constant, if the effect of damping is taken into account, and that the insertion of elastic bearings at the supports of the beam for the purpose of isolating the earthquake forces may adversely amplify the dynamic response of the beam to moving train loads. An envelope impact formula is derived for the deflection of the beam with light damping, which serves as a useful, preliminary design aid to railway engineers.
