Parametric study on collapse margin ratio of structure
来源期刊:中南大学学报(英文版)2014年第6期
论文作者:OU Xiao-ying(欧晓英) HE Zheng(何政) OU Jin-ping(欧进萍)
文章页码:2477 - 2486
Key words:collapse margin ratio; strong ground motion; intensity measurement; probability of exceedance; Housner’s spectrum intensity; spectrum acceleration
Abstract: The determination of collapse margin ratio (CMR) of structure is influenced by many uncertain factors. Some factors that can affect the calculation of CMR, e.g., the elongation of the structural fundamental period prior to collapse, the determination of earthquake intensity measure, the seismic hazard probability, and the difference of the spectral shapes between the median spectrum of the ground motions and the design spectrum, were discussed. Considering the elongation of the structural fundamental period, the intensity measure Sa(T1) should be replaced with in the calculation of CMR for short-period and medium-period structures. The reasonable intensity measure should be determined by the correlation analysis between the earthquake intensity measure and the damage index of the structure. Otherwise, CMR should be adjusted according to the seismic hazard probability and the difference in the spectral shapes. For important long-period structures, CMR should be determined by the special site spectrum. The results indicate that both Sa(T1) and spectrum intensity (SI) could be used as intensity measures in the calculation of CMR for medium-period structures, but SI would be a better choice for long-period structures. Moreover, an adjusted CMR that reflects the actual seismic collapse safety of structures is provided.
OU Xiao-ying(欧晓英), HE Zheng(何政), OU Jin-ping(欧进萍)
(Department of Civil Engineering, Dalian University of Technology, Dalian 116024, China)
Abstract:The determination of collapse margin ratio (CMR) of structure is influenced by many uncertain factors. Some factors that can affect the calculation of CMR, e.g., the elongation of the structural fundamental period prior to collapse, the determination of earthquake intensity measure, the seismic hazard probability, and the difference of the spectral shapes between the median spectrum of the ground motions and the design spectrum, were discussed. Considering the elongation of the structural fundamental period, the intensity measure Sa(T1) should be replaced with in the calculation of CMR for short-period and medium-period structures. The reasonable intensity measure should be determined by the correlation analysis between the earthquake intensity measure and the damage index of the structure. Otherwise, CMR should be adjusted according to the seismic hazard probability and the difference in the spectral shapes. For important long-period structures, CMR should be determined by the special site spectrum. The results indicate that both Sa(T1) and spectrum intensity (SI) could be used as intensity measures in the calculation of CMR for medium-period structures, but SI would be a better choice for long-period structures. Moreover, an adjusted CMR that reflects the actual seismic collapse safety of structures is provided.
Key words:collapse margin ratio; strong ground motion; intensity measurement; probability of exceedance; Housner’s spectrum intensity; spectrum acceleration