Numerical Study on Postfire Behavior of High Strength Steel Flush Endplate Connections

Abstract:

The behavior of high strength steel flush endplate connections on postfire was simulated according to the test results using finite element software Abaqus. Comparison between the analysis results of finite element method (FEM) and all representative experimental results on momentrotation relationship, failure mode and stress distribution of flush endplate connections shows that good agreements exist. Based on above，parametric analysis on Q460 high strength steel endplate connections and Q345 mild steel endplate connections was conducted. Results show that: the degradation of mechanical behavior of the connections is not significant after cooling down from fire temperature 550 ℃; the material property of the endplate has no impact on the initial stiffness of the connections but has important impact on the bending capacity of the connections; a connection with thinner high strength steel endplate can achieve similar bending capacity and equivalent or even higher rotation capacity after fire in comparison with a connection with thicker mild steel endplate.