Investigation of Elevated Temperature Strengths of Cold-Formed Austenitic Hollow Section Beams with a Web Hole

Andy Prabowo, Jonathan Chen

The steel structure is often used as a building structure because it makes the self-weight lighter than concrete while it has relatively high strength. However, the strength and performance of steel structures will deteriorate when caught in fire due to the rising room temperature. Such deterioration occurs in all types of metallic materials, including stainless steel. Until now, investigation on the performance of stainless steel structures at elevated temperatures is still limited, especially on the strength and performance of Square/Rectangular Hollow Section (SHS/RHS) beams. This study investigates the strength predictions for SHS/RHS beams at elevated temperatures dominated by pure bending failure. An additional web hole located at the mid-span was considered, which further deteriorated the SHS/RHS strengths. The investigation was limited to SHS/RHS beams fabricated from cold-formed austenitic (EN 1.4301) sheets. Data on cross-sectional strengths were obtained from numerical analyses using the finite element programme. Results from the numerical analyses exhibited strength deterioration as the temperature rose. Evaluation of the current strength predictions for the cold-formed SHS/RHS austenitic beams using the Direct Strength Method (DSM) showed conservative but not necessarily safe for the condition at elevated temperatures. The proposed modification led to more conservative and reliable, including for the condition at elevated temperatures.