Research On Seismic Resonce Of Prestressed Concrete Frame Under Near-fault Pulse-like Ground Motion

Prestressed concrete frame structure are widely used in large space,large span structures due to its many advantages over other traditional structure.Seismic damage survey indicates the concentricity of seismic damage in near-fault zone,which cause more attention on the near-fault earthquake from scholars in seismology and earthquake engineering.However,research of seismic performance of prestressed concrete frame structure under near-fault pulse-like ground motion need to be further improved.Moreover,there remains controversy about whether prestressed concrete frame designed according to the current seismic design code can meet the demand of near-fault pulse-like ground motion or not.Therefore,two prestressed concrete frames are designed according to code for seismic design of prestressed concrete structures(JGJ140-2004)and the code for seismic design of building(GB50011-2010)and nonlinear time-history analysis is conducted.The main research contents and conclusions are as follows:Firstly,two prestressed concrete frame are designed according to the current seismic design code of which the span is 15 meters,and a numerical model of this frame is developed based on the fiber element in OpenSees.7 far-fault ground motion and 7 near-fault pulse-like ground motion are selected from PEER Ground Motion Database on the basis of 7characteristics of ground motion.Then,the result of nonlinear time-history analysis indicats that both frame PCF1 and frame PCF2 can meet requirement for fortification against earthquake.Rational plastic hinge mechanism of frame PCF2 under near-fault pulse-like ground motion is unreasonable compared of its performance under far-fault ground motion.At last,comparative analysis about seismic response under near-fault pulse-like ground motions with different pulse period is conducted,and the result indicates that,seismic response under near-fault pulse-like ground motions with pulse period close to period of structure is much more violent than seismic response under near-fault pulse-like ground motions with pulse period much bigger or smaller than period of structure,which means the ratio of pulse period and period of structure has great influence on the seismic response of structure under near-fault pulse-like ground motions.