Near-fault earthquake has abundant long period components and large velocity pulses

while long-span cable-stayed bridges adopt a floating or semi-floating system generally and have a lower natural frequency.So based on a long-span cable-stayed bridge with semi-floating system

the 3-D spatial finite element model was built by softwave ANSYS to study the seismic response time history of the bridge under near-fault ground motions and discuss the seismic control technology.The analysis shows that the seismic response of near-fault long-span cable-stayed bridges increases obviously as the ratio of PGV to PGA increases

and the large velocity pulses is quite remarkable;the elastic link is not suitable for controlling the displacement of the deck

while the lead extrusion dampers and viscous dampers can play an important role of seismic control if the optimal design of damper parameters can be carried out.However

because of the significant seismic response of neat-fault long-span bridges

it is quite necessary to increase the allowable displacement of bearings.