Effect of Curvature on the Dynamic Response of Composite Steel I-Girder Bridges

Abstract

Abstract Elaborated three-dimensional finite element models are generated to study the effect of the radius of curvature on the free vibration and dynamic response of the composite steel I-girder bridges. The bridge is modelled by using ANSYS 15.0 program with solid and shell elements to represent concrete and steel members, respectively. AASHTO LRFD HL-93 truck is idealized as 3D model consisting of five lumped masses connected by rigid beams and supported by spring-dampers. The profiles of road surface roughness are generated by MATLAB developed program depend on the power spectral density (PSD). The models used are capable to take all bridge and vehicle characteristics into consideration. The dynamic responses of the horizontally curved bridge are investigated under conditions of various vehicular loading positions. The dynamic behaviour is presented in terms of Impact Factors (IM). The results show that the bridge natural frequencies are significantly affected by the radius of curvature. The relationship between the IM and the radius of curvature is governed by the position of vehicle on transverse sections of the bridge. AASHTO LRFD specification tends to underestimate the values of IM.