Effects of elevated temperatures on cold-formed stainless steel double shear bolted connections

A total of 35 cold-formed stainless steel double shear one-bolted and three-bolted connection specimens were tested using transient state test method. The specimens of bolted connections were fabricated by three different grades of stainless steel. The three different grades of stainless steel are austenitic stainless steel EN 1.4301 (AISI 304) and EN 1.4571 (AISI 316Ti having small amount of titanium) as well as lean duplex stainless steel EN 1.4162 (AISI S32101). The connection tests were conducted at three different load levels of 0.25, 0.50 and 0.75 of the failure load at room temperature. The tendency of the test strength reduction of the stainless steel double shear bolted connections conducted using the transient state test method is similar to those results obtained by the steady state test method. However, the critical temperatures obtained from the transient state test results are generally slightly higher compared with those deduced from the steady state test results at the three different load levels. The austenitic stainless steel grade EN 1.4571 generally performed better than the other two stainless steel grades in transient state tests as higher values of critical temperatures were obtained. Two failure modes, namely the bearing and net section tension failures, were observed in the transient state tests.