Experimental Behavior of Cold-Formed Stainless Steel Screwed Beam-Column Connections at Post-Fire Condition

Abstract

Herein this paper, the experimental behavior of the cold-formed stainless steel screwed beam-column connection with the post-fire condition is presented by performing eight experiments. The beam structural members have been heated beginning from room temperature to 600 degrees C remaining at this temperature for 5-h and letting them cool down back to the room temperature. Energy dissipation capacity, moment-rotation behavior and ductility of the joint under the post-fire condition have been examined by various beam thickness, gusset thickness and with and without stiffeners. The obtained results show that energy dissipation, and rotation decrease due to the sudden breakage of the screws with the increase in gusset plate thickness. Contrast to this outcome, stiffness had a decrease trend, whereas rotation increases when using stiffeners. With the increase of beam thickness, rotation had an increase behavior. Failure modes under the post-fire condition have been compared with the ambient temperature condition. The results indicate that the pre-heating before loading influences the screws' strength more causing a laceration around the screws hence the total collapse of the connection. As using stiffeners increases the strength of the beam at ambient temperature condition, it also gives an advantage under fire condition. Therefore, rare screw deformation has been obtained depending on the beam thickness and gusset plate thickness while wrinkle of the gusset plate and torsion of the beam has been observed.