Reliability-based shear design of corrugated web steel beams for AISC 360 specification and CSA-S16 standard

Abstract

The available literature on the shear strength of corrugated web steel beams (CWSBs) includes a wealth of methods that specify the nominal buckling capacity, but with no consideration of reliability-based design. In the framework of Load and Resistance Factor Design (LRFD) codes, the design of steel members requires load factors to amplify the load effect and a resistance factor to scale-down the resistance based on a target reliability index. Therefore, for full integration of the shear design of CWSBs into the current design codes, resistance factors must be developed and calibrated for use within the LRFD context. This is crucial since the use of existing resistance factors that were specifically developed for welded plate girders for the design of CWSBs may lead to a level of safety that is not consistent with the philosophy of the code. Using a curated database of test results, the present paper attempts to address the lack of a reliability-based design method specific to CWSBs. Two North American design standards were selected in this study, namely, AISC 360 and CSA-S16. A series of reliability analyses are performed first to verify the consistency of reliability indices for welded plate girders designed following the two standards. Then, a probabilistic-based approach is used to calibrate the resistance factors for the shear limit state of CWSBs in accordance with the AISC 360 and CSA-S16 considering dead, live, wind, and snow loads. Finally, an iterative step-by-step procedure is then developed within the LRFD framework to aid in the design of corrugated webs to resist shear loads at ultimate. Findings of the study showed that the current AISC 360 resistance factor for welded plate girders when used for the shear design for CWSB, does not yield a safety level that is consistent with the target reliability; thus, a new factor equal to 0.85 is proposed. For CSA-S16, the current resistance factor of 0.90 for welded plate girders is found to be appropriate for corrugated web steel beams.