Dynamic Amplification of Bridge/Vehicle interaction: a parametric study for a skewed bridge

The dynamic amplification of a bridge response due to moving vehicles has been the subject of numerous research efforts. The efforts indicate a common difficulty in treating the dynamic interaction. This paper presents a semi-analytical technique to solve the bridge/vehicle interaction problem. A skew bridge, idealized as a discretely stiffened thin isotropic plate, is considered. The natural frequencies and mode shapes of the bridge are computed by a pb-2 Rayleigh–Ritz method. The mode superposition principle is then applied. The dynamic response of the bridge to moving vehicle excitation is expressed in terms of mode shapes and normal coordinates. A three-dimensional three-axle vehicle model is developed and consists of 11 independent degrees of freedom. The bridge and the vehicle are treated as two separate systems connected only at the time-varying contact points. An iteration technique is used to deal with the true coupling between the bridge and the vehicle and to satisfy the compatibility of forces and displacements at the contact points. At last, a parametric study is conducted to investigate the dynamic amplification factor. The influences of vehicle type, axle spacing, traffic condition, span length, and skew angle are examined.