Shear capacity modeling for I- and H-shaped steel reinforced recycled aggregate concrete beams: A short communication study based on modified compression field theory

Against the backdrop of resource recycling of construction and demolition waste, the existing calculation methods for shear capacity of steel reinforced recycled aggregate concrete beams in engineering applications fail to fully account for the contribution of recycled aggregate interlock, leading to the core problem of insufficient prediction accuracy. To address this issue, this paper investigates the shear performance of I- and H-shaped steel reinforced recycled aggregate concrete beams based on the Modified Compression Field Theory (MCFT). The study systematically analyzes the shear mechanism of steel reinforced recycled aggregate concrete beams and clarifies the influence law of recycled aggregate interlock on the shear performance of such members. Based on 109 sets of reliable test data of recycled aggregate concrete beams collected from published literature, an empirical formula for aggregate interlock stress is established through regression analysis, which incorporates key parameters including recycled aggregate replacement ratio and shear span-to-depth ratio. Combined with a simplified calculation model for crack inclination angle, an MCFT-based calculation method for the shear capacity of steel reinforced recycled aggregate concrete beams is developed. The proposed method is validated using 18 sets of test data of steel reinforced recycled aggregate concrete beams subjected to shear failure and systematically compared with the calculation methods specified in the current design codes. The results show that the calculation results of the proposed method are in good agreement with the test values and feature higher prediction accuracy and lower dispersion compared with the code methods of various countries.