Screwed connections of thin sheet steels at elevated temperatures - Part II:Transient state tests

摘要

The design rules of single shear screwed connections in the current North American, Australian/New Zealand and European specifications for cold-formed steel structures are based on investigation at ambient temperature. A total of 54 single shear screwed connection specimens were tested at three different load levels using transient state test method. Three thicknesses of sheet steels were used to fabricate the screwed connections. The critical temperature and the corresponding displacement of screwed connections were obtained from the transient state test curves. The test strengths obtained from the transient state tests are similar to those obtained from the steady state tests. The failure modes such as tilting and bearing, screw shear, bearing, and teat out failure were observed in the transient tests. It is found that the failure modes of the screwed connections tested at the lowest load level are generally consistent with those failure modes observed in the steady state tests, and the failure mode may change as the load level increases.