One Dimensional Seismic Site Response Analysis of United Arab Emirates

Abstract

Seismic design of structures located in seismically active areas, like UAE, is primarily based on Seismic Site Response Analysis (SRA) of that area. SRA is the process of estimating the response of soil layers under earthquake excitation (i.e., bedrock motion) and the characterization of earthquake ground motion at the ground surface. This research aims to investigate the significance of shear wave velocity correlation and degradation models on the site response analysis. Three different shear wave velocity correlation equations and two different degradation models have been used in the analysis which reflects the adaptation of laboratory generated, field generated, and literature developed correlations. Moreover, the two different degradation setups replicate the computer programs built-in models and the laboratory generated models, respectively. The lab generated velocity correlation and degradation models were developed using dynamic triaxial machine, binder element test, However, the fields models were developed based on field geophysical instrumentations. A number of 38 boreholes were collected and classified into three categories based on their calculated V30; lowest V30 [V30 ≅ 250 (𝑚/𝑠)], mean V30 [V30 ≅ 300 (𝑚/𝑠)], and highest V30 [V30 ≅ 350 (𝑚/𝑠)]. For each site, one dimensional site response analysis was performed using SHAKE2000. Results have shown that using site-specific shear wave velocity correlation can result in a totally different shear velocity distribution which can either result in different amplification factors or even change the site class of the soil in some cases. Moreover, the outcomes have depicted that the use of laboratory generated degradation models have led to an increase in the amplification factors values with respect to the outcomes obtained from using built-in degradation models. The amount of increase has ranged between 5% to 40%. These results justify the reason to generate site-specific shear wave correlations and degradation models, for seismic site response analysis.