(浙江省水利水电勘测设计院， 杭州 310002)

［摘要］针对纵筋根数较少的钢筋混凝土圆形构件，其纵筋的排列方式将直接影响拉压区的纵筋截面面积和作用力臂；而《混凝土结构设计规范》（GB 50010—2010）附录E.0-4基于纵筋等效连续分布假设、钢筋与混凝土应力简化模型，给出了纵筋根数不小于6时的钢筋混凝土圆形构件正截面承载力计算的非线性方程组（混规推荐简化法），且计算繁琐。基于此，根据混凝土的非线性本构模型、钢筋的理想弹塑性模型，对纵筋离散布置时的钢筋混凝土圆形构件正截面承载力进行了大量公式推导及计算研究分析。结果表明，混规推荐简化法及纵筋连续分布下的混规通法，在纵筋不小于6根条件下，对于大、小偏心构件及受弯构件误差略大；而在纵筋小于6根条件下，对于大、小偏心构件及受弯构件误差会更大。利用MATLAB软件数值编程计算，给出了纵筋5～9根时无量纲轴力-弯矩包络曲线新查算图；同时给出了纵筋连续分布下混规通法的无量纲轴力-弯矩曲线的查算图。最后通过2个算例的对比计算分析，说明新图解法计算步骤简洁、成果精度高，便于工程设计人员应用。

［关键词］钢筋混凝土圆形构件； 纵筋； 离散布置； 非线性分析； 图解法

中图分类号：TU375文献标识码：A文章编号：1002-848X(2019)08-0091-07

A simple graphic method for bearing capacity of normal section of reinforced concrete circular members considering the effect of longitudinal bar arrangement

Huang Chaoxuan

(Zhejiang Design Institute of Water Conservancy and Hydroelectric Power, Hangzhou 310002, China)

Abstract:For reinforced concrete circular members with fewer longitudinal bars, the arrangement of longitudinal bars will directly affect the area of longitudinal bars and the acting arm in the tension-compression zone; while appendix E.0-4 of Code for design of concrete structures (GB 50010—2010) provides the non-linear equations (simplified method recommended by concrete design code) for calculating the normal section bearing capacity of reinforced concrete circular members with not less than 6 longitudinal bars, based on the assumption of equivalent continuous distribution of longitudinal bar and the simplified stress model of reinforcement and concrete, but the calculation is tedious. Based on this, according to the non-linear constitutive model of concrete and the ideal elastic-plastic model of reinforcing bars, a large number of formulas were deduced and analyzed for calculating the normal section bearing capacity of reinforced concrete circular members with discrete longitudinal bars. The results show that the simplified method recommended by concrete design code and the common method of concrete design code with continuous distribution of longitudinal bars have slightly larger errors for large and small eccentric members and flexural members under the condition of no less than 6 longitudinal bars. They have larger errors for large and small eccentric members and flexural members under the condition of less than 6 longitudinal bars. Based on the numerical programming of MATLAB software, the dimensionless axial force-moment envelope diagram of the concrete design code method was provided under the continuous distribution of longitudinal bars, and the dimensionless axial force-moment envelope curve of 5～9 longitudinal bars was also provided. Finally, through the comparative calculation and analysis of two calculation examples, it  shows that the new graphic method has simple calculation steps and high accuracy, which is convenient for engineering designers to apply.

Keywords:reinforced concrete circular member; longitudinal bar; discrete arrangement; nonlinear analysis; graphic method

*浙江省基础公益研究计划项目（LGF18E090004），浙江省水利厅科技计划项目(RC1701), 浙江省水利水电勘测设计院科标业项目（B1609，B1803）。

作者简介：黄朝煊，硕士，高级工程师，Email:516227811@qq.com。