Innovative Spatial Cross System Cable Arrangement for Seismic Response Mitigation of Cable-Stayed Bridges

Using spatial cable arrangement to mitigate seismic responses of long cable-stayed bridges is investigated in this study. The innovative cable system strengthens the bridge using cross arrangement of secondary cables. First, a survey on the constructed cable-stayed bridges was performed to establish the dimensions of typical cable-stayed bridges for analyses. Then, a parametric study was carried out in order to achieve appropriate characteristics for the components of the spatial cable system such as, the layout of the cable system, cable effective area and post tensioning forces. Finally, twelve cable-stayed bridges with different cable layouts and main span lengths of 300, 400 and 500 meters were modeled and analyzed. Analyses were carried out using elastic nonlinear direct integration time-history method under six scaled near-fault earthquake ground motion records in the longitudinal and transverse directions, simultaneously. The main purpose of this study is to investigate the effect of supplementary spatial cable system on the seismic performance of cable-stayed bridges. Effectiveness of spatial cross system cable arrangement was assessed by the reduction observed in the seismic responses of the critical parts of the cable-stayed bridges. It was concluded that supplying cable-stayed bridges with spatial cross system cable arrangement decreases the longitudinal seismic response of the deck and it lowers the shear forces and moments in the pylons, especially in longer span cable-stayed bridges.

Keywords: Cable-stayed bridges; Spatial cable; Cable arrangement; Seismic performance