Seismic collapse risk assessment of super high‐rise buildings considering modeling uncertainty: A case study

Abstract

Based on the multiple stripes analysis method and the first-order second-moment method, a seismic collapse risk assessment considering the modeling uncertainty is carried out for a 118-story super high-rise building with a typical mega-frame/coretube/outrigger resisting system. The sensitivity of the median collapse capacity of the building to eight main parameters is analyzed, and then the modeling uncertainty is determined. Both the effects of the characterization methods of bidirectional ground motion intensities and the selection of the ground motion intensity measure (IM) on the aleatory randomness are investigated. The mean estimates approach and the confidence interval method are used to incorporate both the modeling uncertainty and the aleatory randomness, and then the annual collapse probability, the collapse probability at the maximum considered earthquake (MCE) intensity level and the acceptable values of the collapse margin ratios (CMRs) with different confidence levels for the building are calculated. The results show that the influence of the modeling uncertainty on the collapse capacity of the super high-rise structure is negligible, the aleatory randomness caused by the record-to-record variability is significant, and an appropriate ground motion IM can significantly reduce the aleatory randomness. K E Y W O R D Saleatory randomness, bidirectional ground motions, collapse risk, ground motion intensity measure, modeling uncertainty, super high-rise building

Estimation of Aleatory Randomness by Sa(T1)-Based Intensity Measures in Fragility Analysis of Reinforced Concrete Frame Structures

“…Thirty pairs of far-field ground motions (see Table 3) are selected here from the PEER strong motion database [42][43][44] according to the selection criteria recommended in FEMA P695 [45]. The source-to-distance of the far-field ground motions is greater than 10 km, and enough records from large-magnitude earthquake events are chosen to ensure record-to-record variability.…”

“…Héctor Dávalos et al [48] recommended that it is better to conduct multiple stripes analyses at only two intensity levels, namely, enhanced two-stripe analysis (E2SA). Zhang et al [44] suggested using three IM levels with two levels lower than the estimated median limit capacity in the multiple stripes analysis. In general, an accurate result can be obtained by the IM levels focused on the lower half of the fragility curve.…”