Nonlinear Analysis of Seismic Response Considering the Effects of Site Characteristics and Frequency Content for Shallow and Deep Deposits

The studies have shown that the site characteristics such as soil layers properties and layer thickness can effect on the ground input motion and might change the acceleration frequency content and seismic duration. This research aims to study the effects of site characteristics on the ground response, and the response of the constructed buildings. In order to study the site effects on the ground seismic response, 14 far and near fault earthquake were considered and linear and nonlinear analysis on four different sites was performed. Additionally, one to four story buildings were modeled and the responses were analyzed using SAP 2000 software. Generally, the ground response related to the far and near fault earthquakes, the seismic input motion is amplified while passing through the earth layers and considering the acceleration, the maximum seismic motion increases. The smaller the maximum input acceleration of the seismic input of far fault earthquake, the less is the nonlinear and linear responses. For the cases with the larger near fault earthquake maximum ground acceleration, the analysis of the response, the response analysis using the linear equivalent approach shows that the soil layer of the input motion is amplified while passing through the soil layers. Comparing the graphs of the maximum acceleration versus the depth for the far fault earthquake, it can be inferred that the procedure cannot be generalized for the entire results of the far fault earthquakes. The maximum displacement in the depth increased with increasing the soil deposits thickness. For the similar stories buildings overlaid on the soil deposits, in both shallow and deep cases, the maximum displacement decreases with depth. On the other hand, the maximum obtained displacement in the linear and nonlinear times history analysis increases while increasing the number of building stories.