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Directivity-Induced Pulse-Like Ground Motions and Fracture Risk of Pre-Northridge Welded Column Splices
Recent worldwide earthquakes have emphasized the severe damage potential of pulse-like ground motions caused by forward directivity close to a fault rupture. We investigate the effect of such directivity-induced pulse-like ground motions on the fracture fragility and fracture risk of pre-Northridge welded column splices (WCSs) in near-fault regions. To this aim, incremental dynamic analysis (IDA) is employed to explicitly quantify the pulse effects on WCS stress demands. Two case-study nonlinear welded-steel-moment-resisting-frame (WSMRF) models featuring WCSs (i.e., 4 and 20 story) are developed and subjected to (1) a set of pulse-like ground motions with varying pulse periods; and (2) a suite of ordinary (i.e., non-pulse-like) ground motions. Fracture fragility curves for both ordinary and pulse-like records are then derived from the IDA results. These are finally combined with state-of-the-art near-source probabilistic seismic hazard analysis (NS-PSHA) for a case-study scenario rupture and six representative near-fault sites to assess WCS fracture risk. Findings from the study highlight that directivity-induced pulse-like ground motions affect the estimated fracture fragility and potentially increase the fracture risk of pre-Northridge WCSs in near-fault regions. These findings can guide similar performance-based assessment exercises for WSMRFs to inform, for instance, the planning and design of retrofitting strategies for those vulnerable connections in near-fault regions.
Directivity-Induced Pulse-Like Ground Motions and Fracture Risk of Pre-Northridge Welded Column Splices
Recent worldwide earthquakes have emphasized the severe damage potential of pulse-like ground motions caused by forward directivity close to a fault rupture. We investigate the effect of such directivity-induced pulse-like ground motions on the fracture fragility and fracture risk of pre-Northridge welded column splices (WCSs) in near-fault regions. To this aim, incremental dynamic analysis (IDA) is employed to explicitly quantify the pulse effects on WCS stress demands. Two case-study nonlinear welded-steel-moment-resisting-frame (WSMRF) models featuring WCSs (i.e., 4 and 20 story) are developed and subjected to (1) a set of pulse-like ground motions with varying pulse periods; and (2) a suite of ordinary (i.e., non-pulse-like) ground motions. Fracture fragility curves for both ordinary and pulse-like records are then derived from the IDA results. These are finally combined with state-of-the-art near-source probabilistic seismic hazard analysis (NS-PSHA) for a case-study scenario rupture and six representative near-fault sites to assess WCS fracture risk. Findings from the study highlight that directivity-induced pulse-like ground motions affect the estimated fracture fragility and potentially increase the fracture risk of pre-Northridge WCSs in near-fault regions. These findings can guide similar performance-based assessment exercises for WSMRFs to inform, for instance, the planning and design of retrofitting strategies for those vulnerable connections in near-fault regions.
Directivity-Induced Pulse-Like Ground Motions and Fracture Risk of Pre-Northridge Welded Column Splices
Song, Biao (author) / Galasso, Carmine (author)
Journal of Earthquake Engineering ; 26 ; 2754-2772
2022-04-26
19 pages
Article (Journal)
Electronic Resource
Unknown
Advancing fracture fragility assessment of pre-Northridge welded column splices
| BASE | 2019