Investigation of steel moment-resisting frame relies on deep foundation under normal fault rupture

Recent earthquakes have shown that, besides the seismic forces, the interaction between faults and structures could cause extensive damage to the surface and underground structures. Field observations showed that the need for design measures and regulations for fault loading due to fault movement in areas with active faults seems necessary. In this study, the three-dimensional finite element model in Abaqus finite element program to study the behaviour of a 9-story steel structure with a moment frame system based on three types of mat foundations, piles group, and diaphragm walls was used on sandy soil. The performance of the structural-foundation system 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, this value reaches 1.62%. Also, in most cases, in small amounts of fault movements, the mat foundation system had a smaller difference than the other considered foundation system in this study.