Tests of single shear bolted connections of thin sheet steels at elevated temperatures—Part I: Steady state tests

The current design rules on bolted connections of thin sheet steels for cold-formed steel structures are applicable for ambient temperature condition only. Investigation of single shear bolted connections at elevated temperatures is limited. In this study, 120 single shear bolted connection specimens involving three different thicknesses of thin sheet steels and 30 coupon specimens were conducted by using steady state test method in the temperature range from 22 to 900 °C. There are three main failure modes observed in the single shear bolted connection tests, namely the net section tension, bearing, and tear out. The test results were compared with the predicted values calculated from the American, Australian/New Zealand and European specifications for cold-formed steel structures. In calculating the nominal strengths of the connections, the reduced material properties were used due to the deterioration of material at elevated temperatures. It is shown that the strengths of the single shear bolted connections predicted by the specifications are generally conservative at elevated temperatures. The comparison between the deterioration of the tested connection strengths and that of the material properties at elevated temperatures showed a similar tendency of reduction.

► 120 single shear bolted connections of thin sheet steels were tested.
► 7 different temperatures were considered in steady state test method.
► The design strengths calculated using the reduced material properties are generally conservative at elevated temperatures.
► The reduction of connection test strengths is similar to coupon test results at elevated temperatures.