Shear Lag Effect in Single Plane Cable-Stayed Bridge

Abstract

The shear lag effect in thin-walled trapezoidal box sections with inclined stiffeners within the cell is analyzed using the principle of minimum potential energy. Due to the combined action of axial force and moment in a cable-stayed bridge, the normal stress in the pylon is given by $\bar{\sigma }=N/A\pm M/W$ . The coefficient of shear lag can be written as $\sigma /\bar{\sigma }$ , where σ is the actual stress taking shear deformation of slabs into account and $\bar{\sigma }$ is the stress evaluated by elementary beam theory. In this paper, the longitudinal displacement under axial force is assumed to vary parabolically transversely across the section. Due to moment, a quartic variation is adopted. Two sets of differential equations with boundary conditions are theoretically derived. An example is illustrated by theoretical analysis and test results.