Probabilistic collapse assessment of steel frame structures considering the effects of soil-structure interaction and height

This paper investigates the seismic performance of Intermediate Moment-Resisting Steel Frame structures considering the effects of height and soil-structure interaction. For this purpose, three 3D structures of 3, 6 and 9-story were designed using CSI ETABS software in accordance with ASCE7-16. Then the 2D frames of the structures were simulated by OpenSEES software and to account for the nonlinearity of the material, the plastic hinge elements were used. The 2D frames were analyzed using IDA method subjected to 22 far-field ground motion records of FEMA-P695. Finally, the fragility curves of the structures were developed. The results showed that consideration of soil-structure interaction leads to lower spectral acceleration as height increases, meaning that higher-rising structures have record-induced Sa (T1,5%) closer to Sa (Design), and with decreasing height the difference tends to increase. Exceedance probability decreases with the increase of structure’s height and soil-structure interaction consideration adapts to lower exceedance probability. Also, the investigated Intermediate Moment-Resisting Steel Frame structural models designed according to ASCE7-16 consideration showed to have acceptable seismic performance against far-field records indicating that their exceedance probability in terms of the LS and CP performance level respectively are less than 0.45 and 0.03.