Amplification Effect of Near-Fault Vertical Ground Motions on Horizontal Deformation Response of structures

In this paper, the amplification to structural non-linear displacement response caused by near-fault vertical ground motions is investigated quantitatively. Based on a set of 30 acceleration records of near-fault ground motions, two typical concrete frame structures, as numerical examples, are examined by means of nonlinear dynamic time-history analysis at two different stages: (1) through the application of horizontal components of acceleration records, (2) through application of the combined horizontal and vertical components at the same time. The numerical results show that the maximum floor-displacements of two concrete frames are limitedly amplified by the vertical effect of near-fault ground motion. On the other side, the maximum inter-story drifts are amplified obviously, and the magnification caused by the vertical effect is about 15%similar to 20% on average. Hence it is evident that the amplification of near-fault vertical effect on horizontal deformation response could not be neglected, and worth serious consideration in future seismic design and evaluation.