外方内双螺旋箍筋约束混凝土柱轴压承载力计算方法

约束混凝土可以有效改善混凝土的承载性能和延性,被广泛应用于工程实践中。针对轴压作用下多重箍筋约束混凝土柱的极限承载力计算问题,参考Sheikh提出的有效约束模型理论,建立外方内双螺旋箍筋约束混凝土柱轴压下的约束理论模型。并以约束混凝土计算理论为基础,采用叠加原理和统一强度理论,推导该约束形式下混凝土柱的轴压承载力计算方法,应用有限元软件ABAQUS对该类新型约束混凝土柱进行数值模拟计算。结果表明:外方内双螺旋箍筋约束混凝土柱轴压承载力的理论计算值与模拟值吻合良好,且理论值偏于保守,多重约束混凝土的承载性能明显优于普通箍筋约束混凝土柱的承载性能。

Calculation Method of Axial Compressive Bearing Capacity of Concrete Columns Confined by Double Helix Stirrups and Rectangular Stirrups

Confined concrete can effectively improve the bearing capacity and ductility of the concrete performances,and it is widely used in engineering practice.Aiming at the ultimate bearing capacity of multiple stirrups confined concrete column under axial compression,the newly confined model of concrete columns reinforced with double helix stirrups and rectangular stirrups is established with reference to Sheikh's effective confined model theory.Additionally,the formula for calculating the axial compressive capacity of concrete columns under the above mentioned confined conditions is derived from combining the superposition principle and the unified strength theory based on existing calculation theory of confined concrete.The simulation analysis of the bearing capacity is carried out with the finite element analysis software ABAQUS.The analytical results show that the predicted value of the bearing capacity is in good agreement with the analytical simulated value,and the predicted bearing capacity is somewhat conservative.The performance of the concrete column confined by double helix stirrups and rectangular stirrups is much better than that of the concrete column confined by normal rectangular stirrups.