Structural behaviour of cold-formed stainless steel bolted connections at post-fire condition

This paper presents an experimental investigation on cold-formed stainless steel single shear and double shear bolted connections at post-fire condition. The connection specimens were fabricated by three different grades of stainless steel. The three different grades of stainless steel are austenitic stainless steels EN 1.4301 (AISI 304) and EN 1.4571 (AISI 316Ti) as well as lean duplex stainless steel EN 1.4162 (AISI S32101). The post-fire connection specimens were heated to different nominal temperatures of 350, 650 and 950 °C, respectively, and then cooled down to room (ambient) temperature condition. A total of 82 new connection tests was conducted. The test results of post-fire specimens were compared with those tested without post-fire condition for the same specimen series. Generally, it is found that the single shear and double shear bolted connection specimens cooled down from the nominal temperatures of 350 and 650 °C had higher ultimate strengths than those specimens without expose to high temperatures for all three different grades of stainless steel. The specimens cooled down from 950 °C generally had lower ultimate strengths than the aforementioned specimens. It is also found that the failure modes of cold-formed stainless steel bolted connection specimens at post-fire condition are similar to those tested without post-fire condition. Finally, design rules are proposed for cold-formed stainless steel bolted connections at post-fire condition for temperature up to 950 °C.