Incremental dynamic analysis applied to assessment of structure-specific earthquake IMs in 3D R/C buildings

The present paper investigates the effectiveness of ten structure-specific IMs in reducing scatter in the estimated maximum interstory drift ratios of 3D R/C buildings. For this purpose four medium-rise buildings are studied. Incremental Dynamic Analyses (IDA) are performed for 97 far-fault bidirectional earthquake records. Moreover, in order to account for the variability in the orientation of seismic motion, the two horizontal accelerograms of each ground motion are applied along horizontal orthogonal axes forming 12 different angles with the structural axes. Statistical evaluation of the results identifies certain IMs which lead to small values of scatter in the seismic response. Moreover, it is shown that the efficiency of the examined IMs depends on the special characteristics of the structures, on the degree of nonlinearity experienced by the building, as well as on the incident angle of the seismic input.