Numerical Investigation of Steel Moment-Resisting Frame on Sandy Soil Under Normal Fault Rupture

Recent earthquakes have shown that the interaction between faults and structures could cause extensive damage to the surface and underground structures. Field observations showed that the need for design regulations for fault rupture due to fault movement in areas with active faults seems necessary. In this study, the three-dimensional finite element (FE) model in the Abaqus FE program to study the behavior of a 9-story steel structure with a moment-resisting frame system based on three types of mat foundations, pile group, and diaphragm walls was used on sandy soil. The performance of the system of structure-foundation was evaluated taking into account the structural and geotechnical performance goals such as the drift ratio of floor levels, displacement of the foundation, and distribution of bending moment and shear force along with the pile and foundation. In this study, the position of the foundation relative to the fault line and the foundation type were considered as key parameters. The results of the analysis showed that the best performance in reducing the ratio of the permanent drift ratio of the floors related to the structure with the diaphragm wall system. This was in the case that the edge of the foundation is tangent to the fault line, the residual drift ratio reached 1.62%. Also, in most cases, in small amounts of fault sliding, the mat foundation system had a smaller difference than the other considered foundation system in this study.