Performance of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions

Despite conservative requirements of existing building code regarding clear seismic gap distance of base-isolated (BI) structures to surrounding moat walls, seismic performance of these structures is still ambiguous under severe earthquake ground motions that may push the base slab of the isolation...

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Autores principales: Mona Ghalehnoy, Mostafa Masoudi
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Publicado: Iranian Society of Structrual Engineering (ISSE) 2021
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Acceso en línea:https://doaj.org/article/fb3cebd9ac7d4664bf9e9c825ae01d8a
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spelling oai:doaj.org-article:fb3cebd9ac7d4664bf9e9c825ae01d8a2021-11-08T15:54:39ZPerformance of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions2476-39772538-261610.22065/jsce.2019.190572.1887https://doaj.org/article/fb3cebd9ac7d4664bf9e9c825ae01d8a2021-05-01T00:00:00Zhttps://www.jsce.ir/article_91105_2424518dfd972ea39aebc8283a6c074c.pdfhttps://doaj.org/toc/2476-3977https://doaj.org/toc/2538-2616Despite conservative requirements of existing building code regarding clear seismic gap distance of base-isolated (BI) structures to surrounding moat walls, seismic performance of these structures is still ambiguous under severe earthquake ground motions that may push the base slab of the isolation system to collide to the surrounding moat walls. Moreover, the temptation of reducing seismic gaps in congested urban areas exacerbates the risk of pounding. Excessive horizontal displacement response of these long-period structures subjected to a rare near-field ground motion may lead to pounding to adjacent structures and subsequently, severe and uncontrolled damage or even total collapse of the superstructure.Pounding of BI structures to moat walls is usually considered as an unwanted response that may inflict critical damage to a high importance structure designed for high performance levels. Pounding effects to the moat walls depend on several parameters including superstructure and isolated periods, damping, seismic gap as well as characteristics of the earthquake ground motion. This study aims to evaluate seismic response of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions with different clear gap distances to surrounding moat walls. A seven story and a three story buildings isolated with elastomeric bearings have been modeled. Base slab displacement, global displacement ductility demands, yield strength reduction factors, and maximum inter-story drifts have been computed under recorded severe near-field earthquake ground motions. Results showed that for most of the seismic gaps lower than those of prescribed by codes, seismic demands remain in acceptable ranges corresponding to low performance levels, i.e., life safety or collapse prevention of fixed-base structures. This implies that performance of BI buildings with codified seismic gaps or insufficient seismic gaps is not much different than that of fixed-base buildings when they are pushed to their displacement limits under maximum considered earthquakes.Mona GhalehnoyMostafa MasoudiIranian Society of Structrual Engineering (ISSE)articleseismic isolationpoundingnear-field ground motionsteel moment resisting frameseismic gapseismic performanceBridge engineeringTG1-470Building constructionTH1-9745FAJournal of Structural and Construction Engineering, Vol 8, Iss 3, Pp 266-280 (2021)
institution DOAJ
collection DOAJ
language FA
topic seismic isolation
pounding
near-field ground motion
steel moment resisting frame
seismic gap
seismic performance
Bridge engineering
TG1-470
Building construction
TH1-9745
spellingShingle seismic isolation
pounding
near-field ground motion
steel moment resisting frame
seismic gap
seismic performance
Bridge engineering
TG1-470
Building construction
TH1-9745
Mona Ghalehnoy
Mostafa Masoudi
Performance of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions
description Despite conservative requirements of existing building code regarding clear seismic gap distance of base-isolated (BI) structures to surrounding moat walls, seismic performance of these structures is still ambiguous under severe earthquake ground motions that may push the base slab of the isolation system to collide to the surrounding moat walls. Moreover, the temptation of reducing seismic gaps in congested urban areas exacerbates the risk of pounding. Excessive horizontal displacement response of these long-period structures subjected to a rare near-field ground motion may lead to pounding to adjacent structures and subsequently, severe and uncontrolled damage or even total collapse of the superstructure.Pounding of BI structures to moat walls is usually considered as an unwanted response that may inflict critical damage to a high importance structure designed for high performance levels. Pounding effects to the moat walls depend on several parameters including superstructure and isolated periods, damping, seismic gap as well as characteristics of the earthquake ground motion. This study aims to evaluate seismic response of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions with different clear gap distances to surrounding moat walls. A seven story and a three story buildings isolated with elastomeric bearings have been modeled. Base slab displacement, global displacement ductility demands, yield strength reduction factors, and maximum inter-story drifts have been computed under recorded severe near-field earthquake ground motions. Results showed that for most of the seismic gaps lower than those of prescribed by codes, seismic demands remain in acceptable ranges corresponding to low performance levels, i.e., life safety or collapse prevention of fixed-base structures. This implies that performance of BI buildings with codified seismic gaps or insufficient seismic gaps is not much different than that of fixed-base buildings when they are pushed to their displacement limits under maximum considered earthquakes.
format article
author Mona Ghalehnoy
Mostafa Masoudi
author_facet Mona Ghalehnoy
Mostafa Masoudi
author_sort Mona Ghalehnoy
title Performance of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions
title_short Performance of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions
title_full Performance of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions
title_fullStr Performance of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions
title_full_unstemmed Performance of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions
title_sort performance of base-isolated moment resisting steel frames subjected to pounding effects under near-field earthquake ground motions
publisher Iranian Society of Structrual Engineering (ISSE)
publishDate 2021
url https://doaj.org/article/fb3cebd9ac7d4664bf9e9c825ae01d8a
work_keys_str_mv AT monaghalehnoy performanceofbaseisolatedmomentresistingsteelframessubjectedtopoundingeffectsundernearfieldearthquakegroundmotions
AT mostafamasoudi performanceofbaseisolatedmomentresistingsteelframessubjectedtopoundingeffectsundernearfieldearthquakegroundmotions
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