Dynamic Analysis of Prestressed Concrete Box-girder Bridges By Using the Beam Segment Finite Element Method

A beam segment element formulation is presented for the dynamic analysis of prestressed concrete box-girder bridges, which can conveniently takes into account the effects of the restrained torsion, distortion, transverse local deformation, diaphragms, and prestressing tendons of prestressed concrete box-girder bridges. The spatial displacement field of the beam segment element is directly represented by the nodal degrees of freedom of the corner points. The stiffness matrix and mass matrix of such a segment element are formulated based on the principle of stationary total potential energy in elastic system dynamics. The proposed beam segment element formulation is then implemented to carry out the free vibration analysis of a real case prestressed concrete box-girder bridge. In terms of both natural frequencies and mode shapes, the formulation is verified by the three-dimensional (3D) finite element analysis using a commercial package. It is demonstrated that the proposed beam segment element formulation is suitable and efficient for the dynamic analysis of prestressed concrete box-girder bridges with the advantages of less element numbers and enough accuracy. It is expected that this methodology can be an effective approach for the further dynamic response analysis under all kinds of dynamic loads such as earthquakes, winds, vehicles, and their interaction.