Theoretical Research on the Axial Compression Capacity of Reinforced Concrete Mid-Long Columns Reinforced with Ultra-High-Performance Concrete

Ultra-high-performance concrete (UHPC) is a cement-based composite material characterised by exceptional strength, low porosity and high durability, making it highly promising for reinforcement engineering. Based on the theory of tangential modulus, a calculation method has been developed for the axial compression capacity of reinforced concrete (RC) medium and long columns strengthened with UHPC, using the constitutive relation of materials and internal and external force balance conditions. This study analysed the influence of UHPC reinforcement layer thickness, reinforced layer, reinforcement ratio, column slenderness ratio and initial load level of core columns on the bearing capacity of reinforced columns. The results indicated that the bearing capacity of the mid-long columns increases with the thickness of the UHPC reinforcement layer and its reinforcement ratio. In addition, the bearing capacity decreases with the increase in the column slenderness ratio and initial load level of the core column.