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Indexed by:期刊论文

Date of Publication:2017-02-01

Journal:OCEAN ENGINEERING

Included Journals:SCIE、EI

Volume:131

Page Number:36-47

ISSN No.:0029-8018

Key Words:Rare intense earthquake; Collapse safety reserve; Jacket offshore platform; Collapse margin ratio; Collapse probability

Abstract:The majority of jacket platforms are located in areas of high seismic risk. The seismic performance and overall safety reserve of jacket offshore platforms during rare intense earthquakes must be investigated. This study compares the collapse margin ratio (CMR), reserve strength ratio (RSR) and ductility factor (mu), three frequently used deserve measures. The CMR can comprehensively and simultaneously reflect the contributions of strength and deformation reserve to structural collapse resistance. The results of a case study indicate the CMR increases nonlinearly with increases in the RSR and mu. Comparatively, the collapse safety margin of aseismic jacket offshore platforms is associated more closely with their overall lateral deformability reserve. To satisfy the requirement on the acceptable lower limit of the CMR, as suggested in the ATC-63 report in the case of a structural collapse probability of 10% under rare-level earthquakes, the minimum mu should be met. Furthermore, a simplified method is proposed for the CMR. With the simplified procedures, the computational efficiency of the pushover analysis method used in the assessment of the collapse safety margin of aseismic jacket offshore platforms has been substantially improved without a motion-to-motion evaluation of the collapse-level earthquake intensity required in ordinary pushover analysis.