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对几个典型的基于截面的抗剪设计方法和基于拉压杆模型的抗剪设计方法进行了讨论,并建立剪切试验数据库对其进行了评估比较。显式修正压力场理论(MCFT)方法和加拿大规范CSA-04规范公式分别对钢筋混凝土(RC)梁(剪跨比λ≥2.4)和预应力混凝土(PC)梁(λ≥2.0)的预测精度最高,而对于小剪跨比RC梁(λ≤2.0)和PC梁(λ≤2.5),改进的拉压杆模型(MSTM)和我国《混凝土结构设计规范》(GB 50010—2010)公式的预测结果均偏于安全,但MSTM因合理考虑了预应力贡献,精度较高。基于数据库研究表明,轴向预压应力对梁抗剪的有利作用存在一个上限,而试验研究表明曲线预应力筋竖向分力的抗剪作用同时与剪跨比和纵筋配筋率相关。
Several typical shear-based design methods based on cross-section and shear-resistant design method based on tension-compression rod model are discussed, and the shear test database is established to evaluate and compare them. (MCFT) method and Canadian Standard CSA-04 standard formula are used to predict the accuracy of RC beams (shear span ratio λ≥2.4) and prestressed concrete beams (λ≥2.0) (Λ≤2.0) and PC beam (λ≤2.5), the prediction of MSTM (Improved Tension and Compression Bar Model) and the formula of “Design Code for Concrete Structure” (GB 50010-2010) The results are biased towards safety, but MSTM has higher accuracy because of reasonable consideration of the prestress contribution. Based on the database studies, it is shown that there is an upper limit to the beneficial effect of axial pre-stress on beam shear strength. However, experimental studies show that the shearing effect of vertical component of curvilinear prestressing force is related to shear span ratio and longitudinal reinforcement ratio.