A New Approach for the Free Vibration of Steel Bridge Deck with Stiffeners

Abstract

Based on energy principle, the free vibration of orthotropic steel bridge deck is investigated. The orthotropic steel bridge deck considered to be a stiffened plate. Both longitudinal stiffeners and transverse diaphragms are considered to be beam elements according to the equivalent principle of mass and rigidity. Besides, the plate is analyzed according to classic thin plate theory. The mode shape functions are expressed by the product of two independent beam functions. During the derivation of frequency equation, the lateral flexural effect of both the plate and stiffeners is considered. Besides, the eccentricity and torsion of stiffeners are taken into consideration, as well as the membrane strain energy of the plate. The results of the present approach are validated by the published example. At last, a stiffened plate with three classical boundary conditions is studied. The results show good agreement with the FE software ANSYS. Besides, it is observed that the eccentricity of stiffeners has a greater influence on lower frequencies than the higher, and the dynamic rigidity of stiffened plate can be increased efficiently by increasing the thickness of longitudinal stiffeners or reducing the distance between neighboring stiffeners. But the latter is more efficient.