Sensitivity Analysis of Dynamic Characteristics of Steel Plate Composite Girder Bridge with Supported Cross Beam System

Abstract

A steel plate composite girder bridge with support beam system was selected in the case study and the software of SAP2000 was adopted to build its refined seismic finite element model. A sensitivity analysis about the dynamic characteristics of the bridge was carried out and the design parameters included relative stiffness ratio of beam to slab, shear stiffness of shear nails and steel beam. The results show that: the stiffness ratio of beam to plate has little influence on the low-order modes of structure, but more significant influence on the high-order modes. Furthermore, in the high order modes, the effect of the stiffness of concrete slabs on the dynamic characteristics of high order modes of structures is greater than that of the stiffness of steel girders. Large reduction of the stiffness of shear nails significantly affects the natural vibration period, the order of mode shapes and the mass participation coefficient. Its influence on the vertical dynamic characteristics of bridge is significantly greater than the dynamic characteristics in the longitudinal direction and the in the horizontal direction. Steel beams have little influence on the dynamic characteristics of structures.