Numerical Study on the Surface Fault Rupture Interaction with Soil Deposits and 2-Span Structural Frames

In most studies of faulting-soil-foundation-structural interaction, the structural effects is considered by modeling the equivalent hardness or adding equivalent overload to the foundation. Consequently, direct modeling of the structure is avoided in laboratory and numerical models. Based on the above-mentioned remarks, direct modeling of the structure seems to allow a better understanding of the structure-foundation effect on the distribution of surface fault rupture. In the current study, a 2D finite element numerical modeling of structure-foundation-alluvium interaction has been made by applying reverse surface faulting. The structures are modeled as two span frames with 3 and 7 floors with strip foundation. The effects of different factors on the interaction phenomenon including: location of the structure (Table 1), number of floors and foundation thickness have been studied parametrically. The results of the parametric studies indicated that the most critical situation of the structures occurs when it is located on the hanging wall with a 15 to 25 meters far from the free field fault outcrop. Related to the structural location, the effect of increasing floor number on structural deformation is not unique. Nevertheless, this phenomenon increases the internal forces of structural members. In fact during surface fault ruptures, greater amounts of shear forces and bending moments was created along the beam floors and foundation structures by incasing the floor numbers. Furthermore, increasing the foundation thickness reduces the induced shear forces and moments of the structural members. Consequently, it is recommended to use the foundations with a high thickness for improving the structural performance against surface fault ruptures.