Uniform risk in site-specific seismic hazard analysis

2020 ◽  
pp. 317-324
Author(s):  
Atilla M. Ansal ◽  
İyisan Recep
2017 ◽  
Vol 8 (2) ◽  
pp. 39-59 ◽  
Author(s):  
Swarup Ghosh ◽  
Subrata Chakraborty

This article outlines the performance-based seismic risk assessment (PBSRA) of structures requiring probabilistic seismic hazard analysis (PSHA) to obtain hazard curves and an evaluation of the demand model by a nonlinear structural response analysis under properly selected ground motion records. Unfortunately, such site-specific information is not readily available for Northeast region of India. The present study focuses on these two aspects to supplement the PBSRA. The estimations of hazard curves are demonstrated by considering the seismicity within 300 km radius around the considered locations and specified exposure period. Due to limited availability of natural records in this region, synthetic accelerograms are generated using stochastic point source models by identifying the most contributing magnitude distance combinations from disaggregation of the PSHA results. The significant variabilities observed in the estimated hazard, synthetic accelerograms and nonlinear building responses in the various locations indicate the need of explicit site-specific analysis for PBRSA of structures in the region.


Author(s):  
A. Boominathan ◽  
S. Krishna Kumar

Design ground motions are usually developed by one of the two approaches: site-specific analyses or from provisions of building codes. Although contemporary codes do consider approximately the site effects, they provide more conservative estimates. Hence it is preferred to carry out site specific analysis which involves both the seismic hazard analysis and ground response analysis. This article presents a site specific analysis for a seismically vulnerable site near Ahmedabad, Gujarat. The seismic hazard analysis was carried out by DSHA approach considering seismicity and seismotectonics within 250km radius. The site is predominantly characterized by deep stiff sandy clay deposits. Extensive shear wave velocity measurement by cross hole test is used for site classification and ground response analysis. The ground response analysis was carried out by equivalent linear approach using SHAKE2000. It is found that the deep stiff soil site considered is found to amplify the ground motion. The site specific response spectra obtained from RRS analysis is compared with the codal provision which reveals high spectral acceleration in site specific spectra for mid period range.


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