FULLY COUPLED BUFFETING ANALYSIS OF LONG-SPAN CABLE-SUPPORTED BRIDGES: FORMULATION

Abstract A formulation for fully coupled buffeting analysis of long-span cable-supported bridges is presented, in which dynamic coupling between modes of vibration, dynamic forces on bridge deck and towers and cables, and varying wind speed and structural properties along the bridge deck and towers and cables can be taken into consideration. This formulation adopts a finite element approach and a pseudo-excitation method. Aeroelastic forces on the bridge deck are changed into nodal forces to form aeroelastic damping and stiffness matrices while aerodynamic forces on the bridge deck, towers and cables are converted into nodal forces to obtain a loading vector. After the system equation of motion is assembled, the pseudo-excitation method is applied and the formulation is programmed so that a personal computer can be used to execute the buffeting analysis of the system of hundreds of degrees of freedom in 1 or 2 h. The results from the case study of a long suspension bridge using the proposed formulation and program are also selectively presented in this paper.