Simplified modeling for assessing collapse resistance of steel gravity frames with composite floor systems

Progressive collapse is a structural failure that is initiated by the failure of a primary structural member due to manmade or natural reasons and causes a disproportionately large portion of the structure to damage and/or collapse. This thesis is focused on the computational assessment of the performance of steel gravity frames with composite floor systems under column loss scenarios. The ultimate goal is to provide step-by-step guidance to practicing civil/structural engineers on modeling and analyzing full-size structures by using simple structural analysis software with the purpose of determining progressive collapse resistance. In this research project, a steel frame structure with simple framing connections and a composite floor system was tested, modeled, and analyzed under an interior column loss scenario. For the computational analysis part of the research, a simplified modeling approach was developed and verified by comparing the analysis results with detailed finite element model results and available experimental data. Next, the test specimen was modeled with the proposed approach using the SAP2000 software, and an analysis was performed. Results of the analysis were compared with the test data to verify that the model accurately simulates the measured behavior of the structure. In the end, it was concluded that steel gravity frame structures with composite floor systems can be accurately simulated by using the proposed simplified modeling approach up to the point of first element failure. Moreover, it was shown that practicing civil/structural engineers can do quick and simple checks for their structure’s ability to resist progressive collapse by using the methods and approaches that are described in this thesis.