Abstract:
This paper addresses the behaviour of multistorey structures considering soil–structure
interaction under earthquake excitation. To this end, samples 1, 3, 6, 9, 12 and
15 storey RC plane frames corresponding to aspect ratios (h/ℓ) of 1/3, 1, 2, 3, 4 and
5 are designed based on Turkish Seismic Design Code and analysed in time domain
with incremental dynamic analysis. Inelastic displacement ratios and strength reduction
factors are investigated for designed sample plane frames for 64 earthquake
motions recorded on different site conditions such as rock, stiff soil, soft soil and
very soft soil. According to the analysis result, strength reduction factors of sample
buildings considering soil–structure interaction are found to be smaller than design
strength reduction factors, given the current seismic design codes. This condition
leads to an unsafe design and non-conservative design forces. Besides, inelastic
displacement ratios of fixed-base and interacting cases are found to be quite different
especially for periods shorter than .5 s.
