Vehicle Bridge Interaction analysis on Concrete and Steel Curved Bridges

Abstract

This study investigation is intended to research the dynamic reactions of horizontally curved bridge under heavy vehicle load. Most of the main factors that affect the bridge dynamic response due to moving vehicles are considered.

First, an improved grid model is developed for the analysis of curved bridges based on the shear-flexibility grillage analyzing method, in which the effects of warping stiffness and moment of inertia are both considered. Based on commercial software ANSYS Mechanical APDL, 3D beam element, mass element and spring-damper element are integrated together in building a 3D vehicle and bridge system. A simplified numeric method is developed for solving the interaction problem, considering the effect of random road roughness and its velocity term. This system is tested on two case study bridges, Manchuria concrete bridge and Veteran’s Memorial steel bridge.

Second, with the model and numerical method presented, a series of parametric studies are conducted to study during the curved bridge dynamic interaction. In the study, the effects of curvature of radius, bridge surface roughness, bridge span configuration, traffic lane eccentricities and speed are investigated and analyzed. The dynamic response and dynamic impact factors are calculated and compared. The analysis results provide good references for the stipulation of impact factor formulae in the later studies.

Third, based on the investigation of determining factors of curve bridge dynamic interaction, the expression for upper-bound envelop for impact factors of maximum deflection is given in different surface conditions and highway speed limits as a function of bridge fundamental frequency or bridge central angle. A study is conducted on comparing this empirical equation and serval other major design codes, comments and suggestion are made based on the discoveries.