钢筋混凝土无腹筋梁受剪承载力计算模型误差分析

Error analysis of shear capacity calculation models for reinforced concrete beams without web reinforcement

为提高钢筋混凝土无腹筋梁受剪承载力计算的准确性,收集国内外743根矩形截面无腹筋简支梁的剪切试验数据,对GB 50010—2010《混凝土结构设计规范》、JTG D62—2004《公路钢筋混凝土及预应力混凝土桥涵设计规范》、美国规范ACI 318-11、欧洲规范EN 1992-1-1:2004和Zsutty拟合式的受剪承载力计算式进行误差分析。结果表明:对于集中荷载作用下无腹筋梁的受剪承载力,Zsutty拟合式预测结果的误差较小;纵筋配筋率较低时,GB 50010—2010和ACI 318-11公式的计算结果偏于不安全;EN 1992-1-1:2004公式较好地考虑了尺寸效应的影响。对于均布荷载作用下无腹筋梁的受剪承载力,ACI 318-11精确公式的预测效果较理想,而GB 50010—2010中的公式误差较大。基于计算模型误差分析结果,进一步探讨了我国规范公式的合理性,并通过试验数据的非线性拟合得到无腹筋梁受剪承载力的建议计算式。建议计算式采用统一表达式,能较好地预测集中荷载和均布荷载作用下无腹筋梁的受剪承载力。

In order to improve the accuracy of shear capacity calculation for reinforced concrete beams without web reinforcement,the shear test data of 743 simply-supported rectangular cross-section beams without web reinforcement from home and abroad were collected,and modeling error analysis associated with several calculation models in GB50010-2010,JTG D62-2004,ACI 318-11,EN 1992-1-1: 2004 and Zsutty's formula for predicting shear capacity of reinforced concrete beams were carried out. The results show that when predicting the shear capacity of beams without web reinforcement under concentrated loads,Zsutty's formula provides less biased prediction,GB 50010-2010 and ACI 318-11 may lead to unsafe results when the longitudinal reinforcement ratio is low,and EN 1992-1-1: 2004 considers size effect well. However,for beams without web reinforcement under uniformly distributed loads,the exact formula in ACI 318-11 may be an ideal model,but GB 50010-2010 provides more biased prediction. China 's specification formulas were further discussed based on the statistical results of modeling error analysis,and a calculation formula of shear capacity for beams without web reinforcement was presented by using collected test data to conduct nonlinear fitting. The proposed formula adopts unified expression,which can predict the shear capacity of the beams without web reinforcement under concentrated loads and uniformly distributed loads well.