十字形钢筋混凝土异形柱非线性全过程分析

Nonlinear Analysis on Crisscross Shaped Reinforced Concrete Columns

目的研究十字形柱的抗弯承载力和曲率延性比的变化规律.方法用基于条带划分法的非线性全过程分析方法,考虑混凝土强度、箍筋的体积配箍率、轴压比、荷载角4个影响因素,每个因素考虑三个水平,按正交试验组合9种十字形柱,计算其截面抗弯承载力和曲率延性.结果混凝土强度等级对抗弯承载力影响很大.配箍率可使构件延性获得很大的提高.随着轴压比从0.3增大到0.5的过程中,抗弯承载力逐渐增大;从0.5增大到0.7的过程中,截面抗弯承载能力迅速减小.截面的曲率延性比在整个过程中下降得比较快,随着荷载角从0°增大到30°,抗弯承载力和曲率延性比变化均不大;而荷载角从30°增大到45°,截面抗弯承载力增大,曲率延性比下降.结论钢筋混凝土十字形柱的抗弯承载力和曲率延性比受混凝土强度、体积配箍率、轴压比和荷载角的影响较大,设计时应考虑在内.

The paper aims to study the variation of cross-shaped columns flexural capacity and curvature ductility ratio.The whole process nonlinear analysis based on band division method is applied.Considering the four factors such asconcrete strength,stirrup size of hoop,axial compression ratio,load angle and three levels of each factor are considered.Nine kinds of cross-shaped columns are combined according to orthogonal tests so as to calculate the anti-bending bearing capability and the curvature ductility ratio.The concrete strength greatly influences the flexural capacity.The tie ratio can greatly improve ductility.During the axial compression ratio increases from 0.3 to 0.5,while the sectional anti-bending bearing capacity decreases rapidly when the anti-bending capacity of section increases from 0.5 to 0.7 gradually;Sectional curvature ductility ratio decreases quite rapidly in the process.With the load angle increasing from 0° to 30°,flexural capacity and curvature ductility ratio have no great changes;while the loading angle increases from 30° to 45°,flexural capacity increases and curvature ductility ratio decreases.The conclusion is drawn that the bending capacity and curvature ductility ratio of cross reinforced concrete column will be influenced grealty by concrete strength,hoop ratio of volume,axial compression ratio and load angle.So the above aspects should be taken into account when designing.