A PROPOSED METHOD TO REDUCE VULNERABILITY OF STEEL MOMENT RESISTING FRAMES TO PROGRESSIVE COLLAPSE

Abstract

Progressive collapse may be defined as the spread of an initial local failure from element to element, eventually resulting in the collapse of an entire structure or a disproportionately large part of it. There is uncertainty regarding which column(s) will be lost during extreme events (blast, moving truck collision, plane collision, earthquake, fire, overloading, etc.) which makes it very complicated to consider all the possibilities of column loss scenarios. In addition to the mentioned uncertainty, choosing the proper method of analysis based on the available resources is an important factor to consider — The benefits and drawbacks of each method need to be assessed. In this study, multi-story steel moment resisting frames were studied (6, 9, and 12 floors). Each structure had multiple column loss probabilities that were considered using static linear analysis and dynamic linear analysis methods. The dynamic amplification factor was determined for each structure. A new structural system consisting of tension ties was proposed to improve the performance of structures under the extreme event that causes loss of columns leading to progressive collapse and decrease the domino effect or stop it. The new structural system was checked under different column loss scenarios and its impact on reducing the vulnerability of the structures to progressive collapse was evaluated. Also, a method of simple procedure was proposed to predict the straining actions in members near to the lost column. The research was concluded by a summary of the findings in addition to recommendations for future research.