Mathematical-Mechanical Model of WUF-B Connection Under Monotonic Load

Connections in a steel frame are complex configurations composed of members and elements that contain different geometries, shapes, and material properties. Therefore, one needs to take into account the contributions of such individual components to the overall connection behavior characteristics. This study presents a comprehensive mathematical-mechanical model to determine the welded unreinforced flange-bolted web (WUF-B) connection behavior. The model was developed considering nonlinear characteristics and coupling of individual component properties. The parameters in the mathematical expressions were derived based on collected data from numerical simulations, combined with modified and newly developed mechanical component equations. The models were evaluated by comparing them with finite element analysis results of nonlinear three-dimensional connections. The characterization models, (i.e., equations and procedures) introduced in this paper defined the mechanical properties of the WUF-B connections for a fast and accurate frame analysis of blast-oriented progressive collapse.