Experimental evaluation of the post-fire behavior of steel T-component in the beam-to-column connection

To evaluate the strength of a connection after exposure to fire, the microstructure/property relationships and influences of these effects on high temperature strength are needed to discuss structural elements exposed to a heat treatment and to determine its mechanical properties. This study focuses on understanding the structural behavior of the connection under post-fire conditions. The aim of the work is also to provide a moment-rotation curve, failure mechanism and microstructure for a connection whose component is exposed to heat treatment. This aim was achieved through five tests that were conducted on a full-scale beam-to-column connection using a T-component obtained from rolled I-profiles by cutting along the web plane. The moment-rotation curves and failure modes of the connection at ambient temperature were compared to the moment-rotation curves and failure modes of the connection whose elements were exposed to high-temperature conditions. The material properties of the specimen element exposed to the heat treatment were also investigated by comparing them to those of the original specimen. The test results show that there are differences between the mechanical properties and microstructures of the heated and original specimens. The differences in these specimens are reflected in the morphology of the fractures. The reason for the fractures is that microstructure-changes contribute to brittle behavior in members. The experimental tests indicated that, post-fire, steel connections can be subjected to large deformations at a lower strength and are more likely to fracture early.