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为研究体外预应力对混凝土梁受剪承载力提高的作用机理和体外预应力混凝土梁受剪承载力计算方法,分析钢筋混凝土梁和体外预应力混凝土梁微元体受力特点的区别,探讨体外预应力对受剪性能影响的机理,求解体外预应力对混凝土和箍筋抗剪贡献的提高系数,得到体外预应力混凝土梁受剪承载力理论计算式。采用已有体外预应力混凝土梁剪切破坏的试验数据对理论计算式进行验证,并与各国规范计算结果进行对比。结果表明,理论计算式得到的受剪承载力计算值与试验值的比值均值为0.950,标准差为0.125,提出的计算式可较好地预测体外预应力混凝土梁的受剪承载力,并可以考虑梁的几何尺寸、剪跨比、预应力筋弯起角度、纵筋率、配箍率、纵筋及腹筋屈服强度、混凝土强度等影响因素。
In order to study the action mechanism of external prestress on shear strength of concrete beam and the calculation method of shear strength of external prestressed concrete beam, this paper analyzes the difference of stress characteristics between reinforced concrete beam and external prestressed concrete beam micro- The mechanism of the influence on the shear performance of the external prestress to solve the concrete and stirrups shear contribution to improve the coefficient of shear to obtain the external prestressed concrete beam shear capacity of the theoretical formula. The experimental data of shear failure of prestressed concrete prestressed concrete beams have been used to verify the theoretical calculation formulas and compare them with the results of national normative calculations. The results show that the calculated value of shear capacity calculated by the theoretical formula is 0.950 and the standard deviation is 0.125. The proposed formula can predict the shear capacity of externally prestressed concrete beams, Considering the beam geometry, shear span ratio, prestressing tendon angle, longitudinal reinforcement ratio, stirrup ratio, longitudinal reinforcement and abdominal reinforcement yield strength, concrete strength and other influencing factors.