Relationships Between Significant, Bracketed And Uniform Durations With Earthquake Indices And Site Conditions Using Iranian Seismic Data

In this study, the relationship between different definitions of duration with peak ground acceleration, focal depth, and soil conditions of the site using accelerometer records in Iran was calculated and presented. Then, 1054 three-component records of 197 seismic events recorded with a moment magn...

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Main Authors: M. Rezaeimanesh, H. Saffari
Format: Article
Language:fas
Published: Sharif University of Technology 2021-05-01
Series:مهندسی عمران شریف
Subjects:
Online Access:https://sjce.journals.sharif.edu/article_21958_bb8ce005b228565d381b92d9c2006913.pdf
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author M. Rezaeimanesh
H. Saffari
author_facet M. Rezaeimanesh
H. Saffari
author_sort M. Rezaeimanesh
collection DOAJ
description In this study, the relationship between different definitions of duration with peak ground acceleration, focal depth, and soil conditions of the site using accelerometer records in Iran was calculated and presented. Then, 1054 three-component records of 197 seismic events recorded with a moment magnitude greater than or equal to 5.0 were used. All data for this study were obtained from the Road, Housing, and Urban Development Research Center (BHRC) in Iran. All records were for sites with focal depths and shear wave velocities within the first 30 m of depth. After preparing the records, the baseline correction was performed on them using Fortran programming and durations with g0.05 acceleration thresholds, uniform durations with g0.05 acceleration thresholds, significant durations 5-95% were calculated. Then, according to the Iranian 2800 earthquake code, soil type was grouped and the data were classified into three categories according to soil type. The data with soil group 4 were very low and unreliable. The results showed that with increasing peak ground acceleration, bracketed and uniform duration increased, while for significant durations, records with high significant durations generally have minor peak acceleration. Mathematical relationships were also shown for variations in any durations with peak ground acceleration and focal depth and soil type variations. Also, with softer soil, the slope of the bracketed and uniform duration relationship with PGA increased. Increasing the focal depth decreased the durability with different definitions. After a focal depth of 20 km, a threshold of 0.05g is usually less than 10 seconds. The relationship between shear wave velocity at 30 m depth and significant duration indicated that with increasing shear wave velocity, significant duration decreased. The relationship between the duration and maximum amplitude of earthquake ground motions was important for the seismic design of structures, especially reinforced concrete structures, which suffered from stiffness and reduced strength in successive earthquake cycles.
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spelling doaj.art-c2b0cee16c8d44c3a7255e5205e60f3b2023-08-23T07:41:56ZfasSharif University of Technologyمهندسی عمران شریف2676-47682676-47762021-05-0137.21.19510310.24200/j30.2020.55728.276921958Relationships Between Significant, Bracketed And Uniform Durations With Earthquake Indices And Site Conditions Using Iranian Seismic DataM. Rezaeimanesh0H. Saffari1D‌e‌p‌t. o‌f C‌i‌v‌i‌l, W‌a‌t‌e‌r a‌n‌d n‌v‌i‌r‌o‌n‌m‌e‌n‌t‌a‌l E‌n‌g‌i‌n‌e‌e‌r‌i‌n‌g S‌h‌a‌h‌i‌d B‌e‌h‌e‌s‌h‌t‌i U‌n‌i‌v‌e‌r‌s‌i‌t‌yD‌e‌p‌t. o‌f C‌i‌v‌i‌l, W‌a‌t‌e‌r a‌n‌d n‌v‌i‌r‌o‌n‌m‌e‌n‌t‌a‌l E‌n‌g‌i‌n‌e‌e‌r‌i‌n‌g S‌h‌a‌h‌i‌d B‌e‌h‌e‌s‌h‌t‌i U‌n‌i‌v‌e‌r‌s‌i‌t‌yIn this study, the relationship between different definitions of duration with peak ground acceleration, focal depth, and soil conditions of the site using accelerometer records in Iran was calculated and presented. Then, 1054 three-component records of 197 seismic events recorded with a moment magnitude greater than or equal to 5.0 were used. All data for this study were obtained from the Road, Housing, and Urban Development Research Center (BHRC) in Iran. All records were for sites with focal depths and shear wave velocities within the first 30 m of depth. After preparing the records, the baseline correction was performed on them using Fortran programming and durations with g0.05 acceleration thresholds, uniform durations with g0.05 acceleration thresholds, significant durations 5-95% were calculated. Then, according to the Iranian 2800 earthquake code, soil type was grouped and the data were classified into three categories according to soil type. The data with soil group 4 were very low and unreliable. The results showed that with increasing peak ground acceleration, bracketed and uniform duration increased, while for significant durations, records with high significant durations generally have minor peak acceleration. Mathematical relationships were also shown for variations in any durations with peak ground acceleration and focal depth and soil type variations. Also, with softer soil, the slope of the bracketed and uniform duration relationship with PGA increased. Increasing the focal depth decreased the durability with different definitions. After a focal depth of 20 km, a threshold of 0.05g is usually less than 10 seconds. The relationship between shear wave velocity at 30 m depth and significant duration indicated that with increasing shear wave velocity, significant duration decreased. The relationship between the duration and maximum amplitude of earthquake ground motions was important for the seismic design of structures, especially reinforced concrete structures, which suffered from stiffness and reduced strength in successive earthquake cycles.https://sjce.journals.sharif.edu/article_21958_bb8ce005b228565d381b92d9c2006913.pdfearthquake durationpeak ground accelerationamplitudelocal site conditions
spellingShingle M. Rezaeimanesh
H. Saffari
Relationships Between Significant, Bracketed And Uniform Durations With Earthquake Indices And Site Conditions Using Iranian Seismic Data
مهندسی عمران شریف
earthquake duration
peak ground acceleration
amplitude
local site conditions
title Relationships Between Significant, Bracketed And Uniform Durations With Earthquake Indices And Site Conditions Using Iranian Seismic Data
title_full Relationships Between Significant, Bracketed And Uniform Durations With Earthquake Indices And Site Conditions Using Iranian Seismic Data
title_fullStr Relationships Between Significant, Bracketed And Uniform Durations With Earthquake Indices And Site Conditions Using Iranian Seismic Data
title_full_unstemmed Relationships Between Significant, Bracketed And Uniform Durations With Earthquake Indices And Site Conditions Using Iranian Seismic Data
title_short Relationships Between Significant, Bracketed And Uniform Durations With Earthquake Indices And Site Conditions Using Iranian Seismic Data
title_sort relationships between significant bracketed and uniform durations with earthquake indices and site conditions using iranian seismic data
topic earthquake duration
peak ground acceleration
amplitude
local site conditions
url https://sjce.journals.sharif.edu/article_21958_bb8ce005b228565d381b92d9c2006913.pdf
work_keys_str_mv AT mrezaeimanesh relationshipsbetweensignificantbracketedanduniformdurationswithearthquakeindicesandsiteconditionsusingiranianseismicdata
AT hsaffari relationshipsbetweensignificantbracketedanduniformdurationswithearthquakeindicesandsiteconditionsusingiranianseismicdata