深受弯构件受剪性能影响参数显著性分析

发布时间：2019-02-14 14:46

【摘要】：深受弯构件是指跨高比0l/h(27)5.0的钢筋混凝土构件,其受剪影响因素众多且受剪机理复杂,与一般梁有显著不同。其抗剪计算方法分为两类:一类称为“机理模型”,主要通过优化“抗剪模型”,将抗剪现象和各影响参数通过“模型”中的规律来解释和体现,但计算过程复杂,受尺寸效应影响显著;另一类称为“统计概率模型”,即以传统频率统计学和试验研究结果为基础,合理考虑各影响参数显著性和可靠度水准而建立的概率统计模型,其计算过程简洁,但精度受样本容量影响,且缺乏明确的理论模型。两类方法若能更准确的耦合各影响参数的显著性作用,则能够不同程度提高计算精度,对推进深受弯构件抗剪计算与设计具有重要的理论意义和实际价值。为合理量化不同规范中深受弯构件抗剪影响参数的显著性,本文结合691组受剪试验数据,对比我国规范、美国规范、加拿大规范、欧洲规范对深受弯构件抗剪承载力的计算结果;结合统计软件SPSS,通过相关分析系统地研究了单因素、组合因素对其抗剪能力影响的显著性,采用Kendall相关系数、Spearman相关系数和偏相关系数进行量化评估,确定显著性影响参数;利用主成分分析法给出四项综合指标,分析各指标对实际受剪承载力的影响比重。研究表明:1、各国规范建议公式计算值与试验值吻合较好,我国规范对剪跨比较小的构件计算结果过于保守,基于拉压杆模型的美国ACI318-08、加拿大CSA A23.3-04、欧洲EC2规范对于大剪跨比构件计算结果偏于不安全;2、通过SPSS软件的显著性分析表明,单因素条件下,混凝土强度等级fc'对受剪承载力影响较为显著,截面尺寸b和h0,剪跨比a/h0次之,组合因素下,fc'、bh0、ab、a/h0对受剪承载力影响较显著;3、由主成分分析法得到的四项综合指标分别为几何尺寸综合指标X1、跨高比和纵筋配筋率综合指标X2、混凝土强度等级和腹筋配筋率综合指标X3以及剪跨比综合指标X4,对实际受剪承载力的贡献比重依次为31%、16%、13%、9%。运用统计软件SPSS分析出深受弯构件受剪承载力显著性影响因素,并量化影响因素对受剪承载力的占比,为深受弯构件受剪承载力的计算与设计提供理论参考,为深受弯构件受剪性能的进一步研究提供理论依据,对工程实践中深受弯构件的应用与推广具有重要意义和价值。
[Abstract]:Deep-bending member is a reinforced concrete member whose ratio of span to height is 0l/h _ (27) 5.0. There are many factors affecting shear and complex shear mechanism, which is obviously different from that of general beam. The calculation methods of shear resistance are divided into two categories: one is called "mechanism model", mainly by optimizing the "shear model", the shear resistance phenomenon and influence parameters are explained and embodied by the law in the "model", but the calculation process is complicated. It was significantly affected by the size effect. The other is called "statistical probability model", which is based on the traditional frequency statistics and experimental results, and reasonably considers the significance and reliability of each parameter. The calculation process of the model is simple. However, the accuracy is affected by the sample size and there is no clear theoretical model. If the two kinds of methods can more accurately couple the significant effect of the influence parameters, the calculation accuracy can be improved in varying degrees, which has important theoretical significance and practical value for the calculation and design of shear resistance of deep bending members. In order to reasonably quantify the significance of the parameters affected by shear resistance of flexural members in different codes, this paper compares the data of 691 groups of shear tests with the codes of China, the United States and Canada. The results of calculation of shear capacity of deep flexural members in European Code; The significance of the influence of single factor and combined factor on the shear resistance was studied systematically by using the statistical software SPSS,. The significant influence parameters were determined by quantitative evaluation of Kendall correlation coefficient, Spearman correlation coefficient and partial correlation coefficient. Four comprehensive indexes are given by principal component analysis (PCA), and the specific gravity of each index on the actual shear capacity is analyzed. The results show that: 1, the calculated values of the proposed formulas in various countries are in good agreement with the experimental values, and the calculation results of the components with small shear span in our code are too conservative. The American ACI318-08, Canada CSA A23.3-04based on the tension-compression bar model is applied to the calculation. The results of European EC2 Code for large Shear Span ratio members are unsafe. 2. The significance analysis of SPSS software shows that under the condition of single factor, concrete strength grade fc' has significant influence on shear bearing capacity, section size b and h 0, shear span ratio a/h0 second, and combination factor, fc',bh0,ab,. The effect of a/h0 on shear capacity is significant. 3. The four comprehensive indexes obtained by principal component analysis are geometric dimension comprehensive index X1, span height ratio and longitudinal reinforcement ratio X2, concrete strength grade and web reinforcement ratio X3, and shear span ratio X4, respectively. The contribution proportion to the actual shear capacity is 31 and 13. Using the statistical software SPSS to analyze the significant factors affecting the shear capacity of deep flexural members, and to quantify the proportion of the influencing factors to the shear bearing capacity, which provides a theoretical reference for the calculation and design of the shear bearing capacity of deep flexural members. It provides a theoretical basis for the further study of the shear behavior of deep bending members, and has important significance and value for the application and popularization of deep flexural members in engineering practice.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375

【参考文献】