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

摘要

This study is on progressive collapse analysis of a sample steel building using various procedures suggestednby the General Service Administration and the Department of Defense. The progressive collapse wasnaccommodated by removing columns as per above guidelines. The analysis methods considered were linearnstatic, linear dynamic, non-linear static and nonlinear dynamic using SAP2000 structural simulationnprogram. The analysis model was a 3D nine-storey steel moment resisting building. For linear analysis,nrigid moment connections were used, while for nonlinear analysis pre-Northridge connections were used.nThe effect of an extreme event was incorporated by removing a column in the analysis model. The staticnanalysis was performed on the model with a column removed subjected to static gravity loadings. Thendynamic analysis employed a ramp function to simulate the dynamic effect of the removal of a column.nFor nonlinear analysis, material nonlinearity was incorporated using strength degrading nonlinear hingesnof pre-Northridge connections as per FEMA 356. The paper documents the results of this analysis withncomparison among methods. The potential for collapse and performance levels of the building were determinednusing the demand capacity ratio and the rotational limit obtained through the analysis