Analysis of Orthotropic Plate Bridges

An exact theory for orthotropic plates with either torsionally soft or torsionally stiff eccentric stiffeners, first formulated by Pflüger, is described and generalized. The resulting governing equations are expressed by a set of eighth order differential equations. The approximate character of Huber's fourth order differential equation, which has been the framework of most existing approximate methods of analysis, is examined in the light of the more exact solution. A bridge deck consisting of simply supported rectangular orthotropic plate panels is chosen as an illustration. Numerical solutions are obtained for the study of the following factors: Stresses and deformations in plates with torsionally soft and torsionally stiff eccentric stiffeners based on the exact theory, and the accuracy of an approximate solution based on Huber's equation for a wide range of stiffener dimensions and spacings encountered in actual design.