Influence Analysis of Motion Characteristics of Near-fault Ground Motions on Seismic Responses of Long-period Structures

Near-fault ground motion recordings from the same earthquake event,i.e.Chi-Chi,Taiwan earthquake(Sep.,21,1999),are selected as input,and the influence is analyzed systematically of the characteristics of near-fault ground motions,including rupture directivity,hanging wall and pulse-like motion,on the seismic responses of bilinear single degree of freedom(SDOF) system,base-isolated building and cable—stayed bridge.The computational results illustrate that the structural effect of pulse-like ground motions increases with the increase of initial natural period of bilinear SDOF system,and the pulse effect of structure in the long-period region is most significant.Moreover,the influence of rupture directivity and hanging wall effect of ground motions on the displacement demand of SDOF system is period-dependent.For the base-isolated building and cable-stayed bridge,the structural effect of directivity of near-fault ground motions is remarkable,and the structural effect of hanging wall is distinct.Generally,the characteristic of velocity pulse of ground motions amplifies the dynamic responses of long-period structures.