Resistance of Trapezoidal Sheeting in Fire

Abstract Cold‐formed steel trapezoidal sheeting has a significant decrease of its bending resistance in fire due to the small sheet thickness. The bending resistance is generally reached within 10 minutes of a fire. However, the failure in bending is followed by transitions from bending behaviour to a catenary action. The catenary action can form only if a horizontal support is provided by fasteners to the supporting structure. The fasteners are therefore a critical component of the structural design and usually determine the load capacity of the sheeting in fire. In the presented study, connection tests at both normal and elevated temperature are conducted using two different types of fasteners: self‐drilling screws with washers and powder‐actuated fasteners. For each tested temperature (20, 350, 500, 600 and 700 °C) and sheet thickness (0.75 and 1.5 mm), 4 tests were conducted. The results provide insights into the behaviour of these connections at both normal and elevated temperatures. This paper also describes a large‐scale fire test of a lightweight roof with trapezoidal sheeting. Fastening with self‐drilling screws was used. The fire test consists of two simple beams with a span of 2x4 m and focuses on fastening and the behaviour of a roof above an internal support. Fire test resulted in a failure of the sheeting connection.