EFFECT OF CABLE VIBRATION ON SEISMIC RESPONSE OF SUPER-LONG SPAN CABLE-STAYED BRIDGE

Abstract:

In the seismic response analysis of cable-stayed bridges, cables were generally modeled using single-element cable system (SECS model), which can not simulate the local vibration of cables. In order to investigate the effect of cable vibration on seismic response of super-long span cable-stayed bridge, the Sutong Bridge, which is the longest span cable-stayed bridge in the world, was taken as an example, and its analytical model was established. In this model, cables were modeled with multiple-element cable system (MECS), and rational discretization manner was discussed. The results show that rational discretization manner is dividing each cable into 10 elements. Cable vibration change the dynamics characteristics of the whole bridge, especially cause the appearance of some cable-deck coupled modes, which cause the reduction of participation factor of some modes, the seismic forces of girder and tower are also reduced, especially the axial force of the tower. Furthermore, cable vibration makes the cables, whose frequency are close to vertical vibration frequency of the girder, vibrate seriously.