钢筋混凝土梁受剪承载力可靠度分析

Reliability analysis of shear capacity of reinforced concrete beams

在GB 50010—2010《混凝土结构设计规范》修订过程中,所参考的试验数据主要来自85版设计规范背景资料,其构件数量及试验参数取值范围均存在一定的局限性。通过收集并整理国内外的钢筋混凝土矩形截面简支梁受剪试验数据,对GB 50010—2010《混凝土结构设计规范》中钢筋混凝土梁受剪承载力计算公式的合理性进行分析,得到计算模式不定性的统计参数,并采用考虑基本变量概率分布类型的一次二阶矩方法进行可靠度分析。结果表明:GB 50010—2010《混凝土结构设计规范》中均布荷载作用下钢筋混凝土梁受剪承载力的可靠指标能够满足GB 50068—2001《建筑结构可靠度设计统一标准》的要求;集中荷载作用下钢筋混凝土梁受剪承载力计算公式拟合曲线不再是更新后的试验数据的下包线,其可靠指标既不能满足GB 50068—2001《建筑结构可靠度设计统一标准》的基本要求,也明显低于正截面受弯承载力的可靠指标。建议GB 50010—2010在全面更新试验数据的基础上,校准钢筋混凝土梁承载力计算公式的可靠度。

Although a test database has been created in 1985 and plays an important role in the revision process of the Chinese code GB 50010--2010, the number of members and the range of test parameters have certain limitations. The shear test database was considerably expanded by collecting and filtering the test results of simply-supported rectangular cross-section beams in literatures at home and abroad, which can be used for the rationality evaluation of shear design formula of reinforced concrete beams in the Chinese code GB 50010--2010. The statistical parameters of calculation model uncertainty were obtained, and the first order second moment method considering the probability distribution of basic variables was used for reliability analysis. The results show that when evaluating the shear capacity of reinforced concrete beams with stirrups subjected to uniform loads, the reliability index of calculation formula in the Chinese code GB 50010--2010 can meet the requirements of the Chinese code GB 50068--2001 well. However, for beams with stirrups under concentrated loads, the fitting curve of calculation formula is no longer the lower enveloping curve for updated test data, which can＇t meet the basic requirements of the Chinese code GB 50068--2001, and it is also significantly lower than the reliability index of bending capacity of normal section. The Chinese code GB 50010--2010 is suggested to check the reliability of bearing capacity of reinforced concrete beams after updating test data.