RESPONSE REDUCTION EFFECT OF BUILDINGS DUE TO BASE UPLIFT AGAINST PULSE-LIKE GROUND MOTIONS

We study how pulse period influence response reduction effect due to base uplift. Following results are obtained. 1) We can expect response reduction effect if base uplift occurs when pulse period is nearly equal to or larger than fundamental natural period of buildings. 2) We cannot always expect response reduction effect if base uplift occurs when pulse period is smaller than fundamental natural period and higher modes upper structure and base response are not in the same phase are excited. 3) We cannot expect response reduction effect if maximum shear deformation angle appears before base uplift occurs when pulse period is much smaller.