Comparison of Column Removal Methods in Progressive Collapse Analysis of Reinforced Concrete Moment-Resisting Frames

A building experiences progressive collapse when a primary structural element fails, resulting in the failure of adjoining structural elements, which in turn causes further structural failure. The final failure contains no proportionality to the primary failure. For initial damage, progressive collapse codes and regulations suggest the alternate load path method, which is a threat to independent procedure. However, considering blast loads in analysis is recommended by some researchers. This paper aims to compare various column removal procedures due to blast loads in progressive collapse analysis of reinforced concrete moment-resisting frames. First, the damaged column is identified by analyzing single structural components (columns) under various blast scenarios defined by the quantity of explosive and location of the blast center outside of the structure. To find the damaged columns, three local analyses, static, dynamic, and pressure impulse (P-I), were carried out. A global incremental dynamic analysis of the three-dimensional (3D) damaged structure is the second step of the analysis. This methodology is threat dependent. Therefore, the results are compared to the threat-independent method introduced in guidelines.