Abstract:Based on a real singletower cablestayed bridge, both velocity pulses and real earthquake waves are used to study the influence of ground motion frequency characteristics on seismic behavior of singletower cablestayed bridges. The analysis results show that long duration velocity pulse contained by nearfault ground motions have significant effects on the seismic response of singletower cablestayed bridges. Especially, when the ratio of peak ground velocity (Vp) to peak ground acceleration (ap) is large, the period of velocity pulses gets close to the period of 1st vertical bending mode of the bridge, and thus the response of the tower, girder, cables and bearings increases significantly with possibility that cable relaxation and end span uplift might occur. The results show that cable relaxation and end span uplift have a significant influence on the response of the structure like deck displacement, cable axial force and bearing vertical reactions. The response of the deck displacement and cable axial force would possibly be underestimated if neglecting influence of cable relaxation and end span uplift.
