Screwed connections of thin sheet steels at elevated temperatures – Part I: Steady state tests

► One hundred and two single shear screwed connections of thin sheet steels were tested. ► Seven different temperatures were investigated using steady state test method. ► Connection strengths were predicted using the reduced material properties. ► The current design rules are generally conservative at elevated temperatures. ► Both connection and coupon test results showed a similar reduction tendency. This paper presents a test program on screwed connections of thin sheet steels at elevated temperatures using steady state test method. The single shear screwed connections design rules in the current North American, Australian/New Zealand and European specifications for cold-formed steel structures are not applicable to elevated temperature. A total of 102 single shear screwed connection specimens were tested at elevated temperatures. Three different thicknesses of thin sheet steels were considered in this study. The failure loads and failure modes were obtained from the tests. Several failure modes were observed including the bearing, tilting and bearing, screw shear, net section tension and material failure. The test strengths were compared with the predicted strengths using the current specifications for cold-formed steel structures. The predicted strengths were calculated using the reduced material properties obtained from tensile coupon tests at elevated temperatures. It is shown that the strengths of the single shear screwed connections predicted by the current specifications are generally conservative at elevated temperatures.