S. Hashemi Tabatabaei; A. Mohamadi; A. S. Salamat
Abstract
Earthquake struck Bam city on 12/26/2004. Seismic microzonation of Bam city started with the aim to determine engineering geological and geotechnical characteristic in order to reduce the future earthquake disasters. The seismic microzonation included geoelectric, geoseismic, geotechnic, seismotechtonic, ...
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Earthquake struck Bam city on 12/26/2004. Seismic microzonation of Bam city started with the aim to determine engineering geological and geotechnical characteristic in order to reduce the future earthquake disasters. The seismic microzonation included geoelectric, geoseismic, geotechnic, seismotechtonic, hazard analysis and geotechnical earthquake engineering. Based on seismic results and Standard No. 2800, Bam city can be classified as "Site class I" and " II" .Depth of the seismic bedrock throughout the city approximately is less than 30 m except some portion of central part. The subsurface geotechnical investigation was carried by continuous coring, ten types of soil were identified and their surface and subsurface distributions were mapped. Site response analysis was performed to determine various parameters such as peak acceleration, period corresponding to maximum resonance and coefficient of amplification for various return periods throughout the study area. Results indicated that Bam city can be divided in to four zones with different designed spectra. Some of the design spectra of Bam city were compared with Eurocode and Standard No. 2800.
S. Hashemi Tabatabaei; A. S. Salamat; A. Mohamadi
Abstract
Seismic site characterization studies are carried out in earthquake- prone areas. In these studies seismic design parameters are chosen based on engineering geological and geotechnical characteristics of the site. Site classification is addressed in various building codes. Codes define various methods ...
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Seismic site characterization studies are carried out in earthquake- prone areas. In these studies seismic design parameters are chosen based on engineering geological and geotechnical characteristics of the site. Site classification is addressed in various building codes. Codes define various methods for soil classification such as measurement of average shear wave velocity up to 30 meters depth. This paper present a part of the seismic geotechnical microzonation study of Shiraz city based on seismic data for soil classification. This method, measures the travel times of multiple elastic waves along the interface of layers having different velocities. In this study a seismograph with an array of 24 geophones and 3.75m intervals was used. The shear wave velocity distribution estimated for 3 different seismic layers. Seismic bedrock was defined as layer for which shear wave velocity is more than 750 m/s. Depth of seismic bedrock was estimated to vary about 1 to 29m.The average shear wave velocity up to depth of 30 m ranges about 375 to 1253m/s. Based on the results soil profile in Shiraz were classified and compared with the Standard No. 2800 and Eurocode-08. The result indicated that Shiraz city can be placed in "site class I" and "site class B, E and A" respectively. The study revealed that Standard No. 2800 site classification should be modified.