Compressive Capacity of Postfire Laser-Welded Stainless Steel I-Sections: Testing, Modeling, and Design

This paper presents an experimental and numerical study on the residual compressive capacity of laser-welded stainless steel (LWSS) I-section stub columns after exposure to elevated temperatures. Laboratory testing was conducted first, comprising heating tests, 10 postfire material tests, and 25 postfire compression tests. Upon completing the laboratory tests, numerical modeling was performed, where finite-element models on postfire LWSS I-section stub columns were established and validated. The validated models were employed to perform parametric studies to obtain supplementary numerical data. The acquired results were employed to conduct a comprehensive design analysis, where the room-temperature design methods used in Europe and America and the continuous strength method (CSM) were examined for their suitability for postfire design. The design analysis results demonstrate that the existing design methods lead to moderate design conservatism for LWSS I-section stub columns after exposure to elevated temperatures up to 900°C, owing to its inherently conservative nature. The CSM is evidenced to provide better design accuracy over the European and American standards for the postfire design of LWSS I-section stub columns.