Site Effects Estimation in Tehran City by Using Empirical Methods

In this paper, site effects assessment in Tehran city, the capital of Iran, were estimated by using empirical methods. Both spectral ratio of the horizontal components of sedimentary site to rocky site (Hs/Hr) or site/reference, and Horizontal to Vertical Spectral Ratio (HVSR) methods have been used for estimation the site effects parameters. For this purpose, the recorded motions in BHRC (Building and Housing Research Center) acceleration stations were analyzed. These motions were recorded from Changureh-Avaj (2002), Tehran (2003), Firozabad-Kojour (2004) and Kahak-Qom (2007) earthquakes, which have been occurred near to the Tehran city. Some of these motions recorded in rocky stations and were used for site/reference (Hs/Hr) analysis. Site predominant frequency and soil amplification factor in various frequency ranges were estimated in each station by using calculated amplification functions by two empirical techniques. The results reveal a large contribution of site effects on ground motion at the majority of the studied sites. The value of predominant frequency in southern part of city is less than northern part. Therefore, the level of damage in southern part might be increased and short frequency structures, such as high-rise buildings and long span bridges might be strongly affected by the site effects in this part of the city

Recorded Bedrock Motions and Site Effects Evaluation in Tehran City

In this paper, the results of theoretical analyses related to the evaluation of site effects in Tehran city, the capital of Iran, are presented. To evaluate the response of site, recorded bedrock motions in BHRC (Building and Housing Research Center) acceleration stations at Tehran city were used as bedrock input motion. These motions were recorded during Firozabad-Kojour (2004) earthquake (Ms=6.4), which occurred near Tehran city. Equivalent linear analysis was performed to evaluate the seismic response of each selected geotechnical and geophysical profile subjected to the scaled 475-year bedrock input motion. The results are presented in terms of site response spectrum and site amplification factor, computed in the period ranges 0.1- 0.5 and 0.1- 2.5 s. The estimated site response spectra were compared with the suggested one in Iranian Code (Standard No. 2800). This comparison reveals that there are acceptable trend between the estimated response spectra and Iranian Code. The values of amplification factor in ranges of period 0.1–0.5s and 0.1–2.5 s can also be considered in designing typical and generic buildings of the area

バム強震観測点周辺の建築物被害

The post-earthquake investigations of the Bam, Iran earthquake of Dec. 26, 2003 were conducted by the Joint Reconnaissance Team of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Japan Association for Earthquake Engineering (JAEE), the Architectural Institute of Japan (AIJ) and the Japan Society for Civil Engineers (JSCE) in collaboration with the International Institute of Earthquake Engineering and Seismology (IIEES) from Feb. 23 2004 to Mar. 4 2004. This paper reports the results of a damage evaluation of buildings around the Bam Seismological Observatory operated by the Building and Housing Research Center (BHRC). The results show that many residential houses in the investigated area were seismically vulnerable structures such as adobe and simple masonry structures. Poor construction quality was also found in some of the investigated buildings designed according to the current Iranian seismic code. Moreover, a good correlation between wall area ratio and damage levels was observed. Therefore, wall area ratio may be applicable for evaluating seismic capacity and screening retrofit candidates

Building Damage around Bam Seismological Observatory Following the Bam, Iran Earthquake of Dec. 26, 2003

The post-earthquake investigations of the Bam, Iran earthquake of Dec. 26, 2003 were conducted by the Joint Reconnaissance Team of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Japan Association for Earthquake Engineering (JAEE), the Architectural Institute of Japan (AIJ) and the Japan Society for Civil Engineers (JSCE) in collaboration with the International Institute of Earthquake Engineering and Seismology (IIEES) from Feb. 23 2004 to Mar. 4 2004. This paper reports the results of a damage evaluation of buildings around the Bam Seismological Observatory operated by the Building and Housing Research Center (BHRC). The results show that many residential houses in the investigated area were seismically vulnerable structures such as adobe and simple masonry structures. Poor construction quality was also found in some of the investigated buildings designed according to the current Iranian seismic code. Moreover, a good correlation between wall area ratio and damage levels was observed. Therefore, wall area ratio may be applicable for evaluating seismic capacity and screening retrofit candidates