The Performance of a Steel Connection in Fire: Analytical and Numerical Studies

The performance of steel connections is a crucial, but often overlooked, consideration in the fire protection of steel frame buildings. Traditional methods of fire protection based on limiting the temperature of steel elements below 550°C do not take into account the effects of thermal expansion which can have a significant performance on connection performance in fires. The behavior of a steel seating plate connection in fire is discussed, and it is argued that connections for long span beams need to display adequate ductility, and tolerance of large movements to perform well in fires. This is illustrated by analytical calculations, and nonlinear finite element analysis of a long span steel beam with a simple seating plate connection. Based on these findings, a simple way of estimating beam movements in fire is provided, together with recommendations for required seating plate dimensions for steel beams in fire.