Analysis, Design & Performance
Full Session with Abstracts
339072-2 - A Mechanical Model for Fire Design of Simple Steel Connections
Friday, April 20
9:30 AM - 10:30 AM
Steel connections have an important role in transferring forces from beams to columns, which are designed to sustain gravity loads at ambient temperature. However, during fire, steel connections are subjected to additional thermal induced forces and degradation of strength and deformation capacities. Moreover, due to fire temperatures, steel connections experience a significant material degradation, which makes their behavior and design complex during fire. Therefore, it is important to develop a design procedure of simple steel connections at fire temperatures. The objective of this study is to develop a mechanical based design model which will be considered as a practical tool for the analysis and design of steel connections to professional fire-engineers in the US. This model predicts the behavior and to design three different simple beam-column steel connections when subjected to elevated temperatures. This includes double angle, shear tab, and shear endplate connections along with design examples. The model incorporates the connection rotation of key component elements, and includes nonlinear behavior of bolts and base materials at elevated temperatures. The proposed model includes linear and nonlinear springs which model the strength, stiffness, and rotation capacities of each connection component. The proposed model is validated against experimental and finite element (FE) results available in the literature, under steady-state temperature analysis. The proposed model is capable to cover all possible limit states and governing failure modes under variable loading and temperature conditions. Different geometric and material properties are considered in the design and behavior of those simple connections. Fire design examples on shear tab, double angle, and shear endplate connections are presented based on the proposed model. This provides structural fire engineers a step-by-step procedure for designing steel connections in fire, bridging the gap between research and practice of structural-fire safety design.