Dynamic Analysis of Horizontally Curved I-Girder Bridges

The finite element displacement method is used with annular plate, thin-walled curved beam, straight prismatic beam, and frame-type diaphragm elements for the dynamic analysis of horizontally curved I-girder highway bridges. The stiffness and inertia properties of the finite elements are obtained within the bounds of linear elasticity and small displacement theories. Warping of the girder cross section due to torsion is included in the analysis. The moving vehicle on the bridge is idealized as a sprung mass supported on two unsprung masses. The centrifugal forces arising due to the motion of the vehicle in a circular path are included in the analysis. The inclusion of the vehicle inertia in the bridge-vehicle interaction results in a set of differential equations, the coefficients of which depend on the speed of the vehicle and thus are not constant. These equations of motion are solved by the linear-acceleration method of numerical integration.