In the last two decades,seismic resilience(SR)has been developed as a main concept for the assessment of the structural vulnerabilities of buildings and city centres.In particular,historical centers consist of adjacen...In the last two decades,seismic resilience(SR)has been developed as a main concept for the assessment of the structural vulnerabilities of buildings and city centres.In particular,historical centers consist of adjacent buildings organized in blocks with common characteristics and similar typologies.The paper proposes a meth-odology to quantify SR for urban regions,by overcoming the state of the art studies that focus on assessing the SR for singular buildings.In this regard,the presented methodology may calculate the SR of blocks of buildings for the assessment of recovery investments of historical city centers.The main idea is to assess the level of vulnerability by accurate 3D surveys and visual inspections in order to select empirical fragility curves.The proposed methodology was herein applied to the city center of San Marino,designated by UNESCO as a world heritage site.展开更多
This paper presents the development and testing of a novel internal dissipation connection for the use of post-tensioned rocking columns.The solution is one of the many referring to the dissipative controlled rocking(...This paper presents the development and testing of a novel internal dissipation connection for the use of post-tensioned rocking columns.The solution is one of the many referring to the dissipative controlled rocking(DCR)bridge design philosophy.The internal dissipaters are carefully designed to be cost-effective and reduce the over-all construction cost.The dissipaters are fully threaded,Grade 300 bars connected to the permanent column and foundation longitudinal reinforcement with threaded couplers.In this research,a DCR column is subjected to subsequent earthquake events,and the dissipaters’strain design limits are chosen such that there is no need for replacing after a significant seismic event.The result is a recommended design strain limit of 1.5%for the dissi-paters that guarantees the structural integrity of the DCR column after a seismic event.Additionally,a cumulated strain of 5%is recommended for the dissipaters before replacement is suggested.The proposed connection de-tailing with replaceable internal dissipaters,combined with post-tensioned high strength bars and well-confined concrete,provided self-centring capabilities(no residual displacement),dissipation capacity and significantly less damage in the bridge column than a traditional reinforced concrete solution.展开更多
A three-tower connected reinforced concrete(RC)frame building was selected as a prototype building and used to investigate resilience-based seismic design,aiming to provide a reference for multitower-connected buildin...A three-tower connected reinforced concrete(RC)frame building was selected as a prototype building and used to investigate resilience-based seismic design,aiming to provide a reference for multitower-connected buildings by using seismic isolation.First,a seismic resilience assessment strategy was recommended based on the characteristics of the case study.Specifically,the restoration cost index was recommended as the ratio of the total repair cost of multiple towers and connection parts with respect to the current replacement cost.In contrast,repair time and casualties were recommended as the longest repair time and the highest casualties of multiple towers due to their uncoupled functions.The influences of the critical design parameter of the isolation system(i.e.,yield ratio)on the resilient performance of the entire building was investigated.Both the repair cost and time of the building decreased at decreasing yield ratios,which were attributed to the notable control of the maximum absolute floor acceleration.Only the case study,which showed a yield ratio of 2%,achieved the highest resilience level,as regulated by the relevant Chinese code.Hence,a 2%yield ratio is recommended for the conceptual design of seismically isolated multitower-connected buildings to achieve good seismic resilience.展开更多
文摘In the last two decades,seismic resilience(SR)has been developed as a main concept for the assessment of the structural vulnerabilities of buildings and city centres.In particular,historical centers consist of adjacent buildings organized in blocks with common characteristics and similar typologies.The paper proposes a meth-odology to quantify SR for urban regions,by overcoming the state of the art studies that focus on assessing the SR for singular buildings.In this regard,the presented methodology may calculate the SR of blocks of buildings for the assessment of recovery investments of historical city centers.The main idea is to assess the level of vulnerability by accurate 3D surveys and visual inspections in order to select empirical fragility curves.The proposed methodology was herein applied to the city center of San Marino,designated by UNESCO as a world heritage site.
文摘This paper presents the development and testing of a novel internal dissipation connection for the use of post-tensioned rocking columns.The solution is one of the many referring to the dissipative controlled rocking(DCR)bridge design philosophy.The internal dissipaters are carefully designed to be cost-effective and reduce the over-all construction cost.The dissipaters are fully threaded,Grade 300 bars connected to the permanent column and foundation longitudinal reinforcement with threaded couplers.In this research,a DCR column is subjected to subsequent earthquake events,and the dissipaters’strain design limits are chosen such that there is no need for replacing after a significant seismic event.The result is a recommended design strain limit of 1.5%for the dissi-paters that guarantees the structural integrity of the DCR column after a seismic event.Additionally,a cumulated strain of 5%is recommended for the dissipaters before replacement is suggested.The proposed connection de-tailing with replaceable internal dissipaters,combined with post-tensioned high strength bars and well-confined concrete,provided self-centring capabilities(no residual displacement),dissipation capacity and significantly less damage in the bridge column than a traditional reinforced concrete solution.
基金National Key Technology R&D Program of China under Grant No.2022YFC3003600。
文摘A three-tower connected reinforced concrete(RC)frame building was selected as a prototype building and used to investigate resilience-based seismic design,aiming to provide a reference for multitower-connected buildings by using seismic isolation.First,a seismic resilience assessment strategy was recommended based on the characteristics of the case study.Specifically,the restoration cost index was recommended as the ratio of the total repair cost of multiple towers and connection parts with respect to the current replacement cost.In contrast,repair time and casualties were recommended as the longest repair time and the highest casualties of multiple towers due to their uncoupled functions.The influences of the critical design parameter of the isolation system(i.e.,yield ratio)on the resilient performance of the entire building was investigated.Both the repair cost and time of the building decreased at decreasing yield ratios,which were attributed to the notable control of the maximum absolute floor acceleration.Only the case study,which showed a yield ratio of 2%,achieved the highest resilience level,as regulated by the relevant Chinese code.Hence,a 2%yield ratio is recommended for the conceptual design of seismically isolated multitower-connected buildings to achieve good seismic resilience.
