Inelastic analyses of a l7-story steel framed building damaged during Northridge

摘要

A series of two- and three--dimensional static and dynamic inelastic frame analyses are performed for a 17-story steel moment frame building damaged by the 1994 Northridge earthquake. The primary objectives of the study are to: (1) exercise state--of--the-art inelastic static and dynamic analyses for the evaluation and design of steel buildings; (2 ) establish to what degree frame analyses can be used to predict the types of brittle connection damage that occurred dur- ing the Northridge earthquake; and (3) investigate the reliability of the analyses and the influence of modeling parameters on com- puted performance indices. In general, this study shows that calcu- lated interstory drift ratios and curvature demands obtained from inelastic time history analyses correlate reasonably well with the pattern of connection damage observed in the building. However, there is significant scatter in the computed deformation demands that are strongly dependent on the degree to which three-dimen- sional torsion, secondary structural elements and strength/stiffness degradation (associated with connection fractures) are modeled in the analyses. Further, comparisons of static and dynamic analyses indicate that for this building static pushover analyses do not cap- ture higher vibration modes that are significant.