A new criterion for considering soil-structure interaction on analysis of moment frames

Abstract

There is no general criterion to determine the necessity of considering the soil-structure interaction in codes. In this study, the effects of considering soil on seismic response of structures are assessed by direct and equivalent spring-dashpot methods. The moment frame structures with three to ten stories located on different soil types are analysed. The results show that considering soil-structure interaction in some models causes an increase and a decrease up to 2 times and 0.6 times in storey shears, respectively. The maximum increase is related to ten-storey buildings which are located on soil type IV and the maximum decrease is related to three-storey buildings which are located on soil type II. Also, considering the soil-structure interaction increases the structure principal period. Finally, a new criterion for determining the necessity of considering soil-structure interaction is presented. In the criterion the soil type, shear wave velocity, natural frequency of structure and building height are considered.