Progressive collapse analysis of a steel building with pre-northridge moment connections

Abstract

SUMMARY This study is on progressive collapse analysis of a sample steel building using various procedures suggested by the General Service Administration and the Department of Defense. The progressive collapse was accommodated by removing columns as per above guidelines. The analysis methods considered were linear static, linear dynamic, non-linear static and nonlinear dynamic using SAP2000 structural simulation program. The analysis model was a 3D nine-storey steel moment resisting building. For linear analysis, rigid moment connections were used, while for nonlinear analysis pre-Northridge connections were used. The effect of an extreme event was incorporated by removing a column in the analysis model. The static analysis was performed on the model with a column removed subjected to static gravity loadings. The dynamic analysis employed a ramp function to simulate the dynamic effect of the removal of a column. For nonlinear analysis, material nonlinearity was incorporated using strength degrading nonlinear hinges of pre-Northridge connections as per FEMA 356. The paper documents the results of this analysis with comparison among methods. The potential for collapse and performance levels of the building were determined using the demand capacity ratio and the rotational limit obtained through the analysis. Copyright © 2010 John Wiley & Sons, Ltd.