Flexural performance of concrete‐filled steel tubular beams with wood chip aggregate

Abstract This study investigates the flexural performance of concrete‐filled steel tubular (CFST) beams with partial replacement of aggregates by wood chips (0%–25%) through experimental and numerical analysis. This study is novel in that it experimentally and numerically investigates the flexural behavior of CFST beams with partial replacement of conventional aggregates by wood chips. The study quantifies the influence of replacement ratio and cross‐sectional geometry on strength, ductility, and failure modes, and establishes an optimal replacement level that achieves sustainability without compromising structural performance. Fourteen CFST beams (seven circular, seven square) were tested under four‐point bending to evaluate the effects of wood chip content on failure modes, load–deflection behavior, ductility, and confinement efficiency. Results indicate that 5% wood chip replacement retains comparable strength to conventional CFST beams while improving ductility up to 25% in circular sections. Higher replacements reduce strength by up to 37% in square beams but maintain acceptable ductility in circular sections due to uniform confinement. A finite element model is validated against experimental data. The model accurately simulates nonlinear behavior and failure mechanisms. Circular CFST beams demonstrate superior performance over square sections under wood chip incorporation. The study concludes that 5% wood chip replacement optimizes sustainability and structural performance, while higher ratios require careful consideration for load‐critical applications.