Dynamic analysis of cable-stayed bridges under moving stochastic loads

To obtain the dynamic response of bridges under moving loads, a virtual loaded element approach is proposed. In each time step, the load moves from one end of the virtual element to the other. At an arbitrary instant within this time step, the load is firstly decomposed to the nodes of the virtual element, which are then further decomposed to the nodes of the actual structural element. Therefore the method is not affected by the time-step size. However it can effectively simulate the continuous movement of the load, and in particular it can easily deal with the cases when the load crosses the structural ( finite) elements. When the moving load is stochastic, an improved precise integration method is suggested in combination with the pseudo excitation method to solve such problems more accurately and efficiently. A simple supported beam bridge and a real cable-stayed bridge under a moving load are analyzed and compared with the reference solutions to show the effect of the proposed method.