Free vibration analysis of cable-stayed bridges by dynamic stiffness method

In most dynamic analyses of cable-stayed bridges, the stay cables have been modeled as single truss elements. This method is simple but it is inadequate in the accurate dynamic analysis of a cable-stayed bridge because it essentially precludes the lateral cable vibrations. In this paper, free vibration analysis of cable-stayed bridges by dynamic stiffness method is presented. This method is chosen because of its superior accuracy. The solution suffers no loss of accuracy even though each cable is modeled as only one element in the analysis. Not only is the number of elements in the global structural assembly greatly reduced, but also the vibration characteristics of stay cables are automatically taken into consideration. The proposed method is applied to a two-dimensional cable-stayed bridge model to demonstrate its validity and versatility.