One-Sided Steel Shear Connections in Progressive Collapse Scenario

Abstract

There are many design techniques and philosophies intended to provide structural integrity or increase structural robustness, thereby making structures resistant to progressive collapse. However, studies that reveal origins and levels of inherent robustness in structural steel members and systems are limited. The present study sought to lay a foundation for the process of behavior evaluation of components and assemblages initially designed for purposes other than progressive collapse, such as gravity loads, and make recommendations regarding their performance and possible methods for improvements for the new scenario. These recommendations can lead to more economical design and safer structural steel systems in the event of localized damage that has the potential to spread to a disproportionately large part of the structure. Connections play a major role in ensuring general integrity of different types of steel structural systems. Hence, numerical investigations were performed to extend the current body of knowledge on connections and, consequently, the structural response in the event of progressive collapse. This study was intended to examine the response of steel frames with simple shear connections in the aftermath of unusual and extreme localized loads. The main goal of this research was to evaluate the behavior of some prevalent and economical one-sided (i.e., connected only on one side of the supported beam web) shear connection types—shear tab, tee (WT), and single angle—in buildings and perform numerical analyses on those connection configurations under extreme loading scenarios represented generically by the so-called column-removal scenario. Characteristic features of the connection response, such as the potential to develop a reliable alternative load path through catenary action and ultimate rotational capacities, are discussed to provide a solid foundation for assessing the performance of buildings with these types of connections. Observations regarding the analysis results were synthesized and conclusions were drawn with respect to the demands placed on the connections. The results of this research contribute to a better understanding of the resistance of steel structures with one-sided shear connections to progressive collapse.