Response of Steel Reduced Beam Section Connections Exposed to Fire

Abstract

Steel structures may be vulnerable to fires; therefore, work is underway in several quarters to advance performance-based engineering (PBE) of steel frames for fire conditions. Both experimentation and finite-element simulations are necessary tools in PBE for assessing the behavior of structures under elevated temperatures. Numerical modeling of the overall structural system using line-element models fails to capture the localized behavior of connections due to the simplistic nature of such models. With advances in computation, attention is shifting to three-dimensional (3D) models, which are better able to capture the behavior of connections. Accurate predictions of structural response require the inclusion of realistic boundary conditions such that the interaction between the connections and the surrounding structure is properly captured. The study reported herein evaluates the response of steel frames with reduced beam section (RBS) connections under a typical compartment fire, with temperature-varying boundary conditions that represent the constraints provided by the remainder of the frame. The results of the study highlight the significance of including realistic boundary conditions during fire simulations. In addition, the results quantify the demand on such connections and contribute to the advancement of performance-based fire engineering.