Journal of Structural and Construction Engineering (Aug 2021)
Numerical Study of Site Effects on the Amplification of Earthquake Waves in the Fooladi Area of Sarpol-e-Zahab City
Abstract
The amplification pattern of earthquake waves and extensive damages due to that in alluvial valleys are influenced by two phenomena such as alluvial characteristics and topographic features of the site. Therefore, local effects assessment of the site is considered as one of the effective parameters in designing reinforced structures to withstand seismically excitations. For the first time after the destructive and historic earthquake on November 12, 2017, in Sarpol-e-zahab, using geotechnical reports of drilled boreholes by housing foundation, this article has studied two dimensional modelings of the subsurface structure of Fooladi zone. Sarpol-e-zahab's bedrock accelerogram was also used to perform nonlinear dynamic analysis using ABAQUS software. The response spectrum of different parts of soil surface was used in one and two-dimensional forms to investigate the impacts of topographic and stratigraphy factors. Determining the dominant dynamic period of the site and the maximum amplification values are the other findings of this study. The amplification graph over different times shows buildings with the periods from 0.7 to 1.1 seconds have been affected amplification and site factors more than any other period. In the end, considering the calculation of the average shear wave velocity up to 30m borehole, the investigated land showed the highest compatibility with level 3 of land type classification table of Standard Code No.2800 and response spectra obtained from this study were compared with design spectrum of Standard Code No.2800. Contrary to the fifth edition published report of the International Institute of Earthquake Engineering and Seismology (IIEES), the findings generally show the right and appropriate performance of the Standard as well as using tall structures with sufficient safety.
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