Failure threshold analysis of weathering steel composite beams subjected to stress corrosion

Composite beams are highly regarded for their excellent mechanical properties and are widely used in civil engineering. Current research focuses on their novel materials and structural forms. However, a thorough investigation of the failure thresholds prior to structural collapse is lacking. This paper addresses this issue using weathering steel concrete composite beams (WSCCBs). Firstly, an overall stress corrosion experiment is carried out on the pre-cracked WSCCBs. Then, based on the statistical pattern derived from the experimental data, an L-index is proposed to identify the failure thresholds. The failure mechanism is then analyzed using sectional strain/stress fields and internal forces. FEM simulations are used to validate the effectiveness of the L-index. Finally, a new prediction method is proposed to determine the failure thresholds and ultimate capacity of composite beams under positive and negative bending moments. This research endeavours to provide anew perspective for the failure assessment and safety design of composite beams.