Seismic Evaluation of DBD12 Model Code Provisions in Design of RC Moment Frames Considering Soil–Structure Interaction Effects

Today, conventional force based structural design (FBD) approach due to the weakness in controlling the expected performance level during an earthquake, do not meet the performance expectations of the designer. Direct displacement based design approach (DDBD) is recognized as one of the new main tools for satisfaction designer expected performance level. The effectiveness of DDBD approach has been evaluated in controlling the expected performance level of many structural systems so far, while the least attention has been paid to the effects of geophysical and site effect studies. In this study, seismic performance of RC frames designed with DDBD approach considering soil–structure interaction effects has been investigated. For this purpose, 4 RC frames with different heights that are placed on a 20 meters layer of soil were designed based on mentioned approaches. In the design process, the design displacement profile has been corrected according to the effect of soil-flexibility. The results of the study of frames with flexible bases show an increase in the displacement response of frames up to 8.22% compared to models with fixed bases. While the effects of soil-structure interaction did not have much effect on the story drift, so that in none of the frames the average maximum story drift did not exceed the expected performance level. In order to comprehensively investigate the soil–structure interaction effects, the performance evaluation of the RC frames in low-, medium-, and high-risk has also been examined. The results show minor changes in the maximum story drift at three different risk levels, considering soil–structure interaction effects.