On the Studies of a Bridge-Vehicle System

Abstract

Traditionally, dynamic effects on bridge decks brought about by moving vehicle loads, are taken into account by increasing the static loads by an impact factor. Recent researchers have found that actual impact factors can be much higher than the recommendations given in various bridge design codes of practice and hence the subject needs investigation. This paper describes the formulation of a computer based bridge-vehicle system to study the dynamic behaviour of bridge-vehicle interaction. The modelling of the bridge itself is using finite element formulation of quadrilateral flat shell elements with eccentric beam stiffeners. The vehicle is modelled as a rigid body with two-axle and four-wheel sprung load units. Because of the effect of interleaf friction in the suspension system of the vehicle, the load-deformation relationship for the spring is represented by a hysteretic bi-linear diagram. In addition, the surface roughness of the bridge pavement is considered as a stationary random process characterized by a power spectral density function. The results of the model are compared with other similar works. The verification processes for the theoretical bridge-vehicle interaction system has demonstrated that it is possible to model in-service behaviour and to achieve results which are quantitatively as well as qualitatively descriptive of actual performance. The developed computer based model can further be used for parametric studies to investigate the cause of high impact factors.