Dynamic Analysis of Curved Box-Girder Bridges

The finite element technique is used for the forced vibration analysis of horizontally curved box girder bridges. Annular plates and cylindrical shell elements are used to discretize the slab, bottom flanges and webs. Rectangular plate elements and pin-jointed bar elements are used for diaphragms discretization. A vehicle, as the applied time varying forcing function, is simulated by two sets of concentrated forces, having component in the radial and transverse directions and moving with constant angular velocities on circumferential paths of the bridge. The effect of centrifugal forces is considered and the effect of damping of the bridge is neglected in the analysis. The mass condensation technique is used to reduce the number of coupled differential equations obtained from the finite element method. The resulting differential equations are solved by the linear acceleration method. A number of bridges with practical geometries are analyzed and impact factors are calculated.