混凝土拉压杆模型最小拉压杆夹角取值范围研究

混凝土深梁抗剪设计和应力非规则区设计一直是工程界的难题，目前普遍认为拉-压杆模型法是设计混凝土深梁和应力非规则区比较有效的方法之一，已经被多国规范所采纳。虽然各规范都认识到拉、压杆之间的夹角取值对设计和验算结果的影响，并对此做了相应的规定，但都没有明确地将腹板的配筋率，腹板钢筋的屈服强度和混凝土的极限抗压强度等因素联系起来，因此有必要对此做进一步深入的研究。通过控制腹板钢筋屈服先于混凝土压杆的破坏，防止结构发生脆性破坏为条件，推导了拉、压杆之间最小夹角与腹板的配筋率，腹板钢筋的屈服强度和混凝土的极限抗压强度等因素之间的关系表达式，得到了一些有意义的结论。

Research on Minimum Range of Angle between Strut and Tie of Concrete Strut and Tie Model

The anti-shear design for deep beam and irregular stress zone is still a tough task. At present, strut-and-tie model method is regarded as one of effective methods to design deep beam and stress discontinuous zone and is adopted by many codes. Although all the codes note that the angel range between strut and tie has significant influence on the designing and checking result, and corresponding specifications of angle between strut and tie have been made, yet none of the specifications relate such factors as the ratio of web reinforcement, stirrup yield strength and the compress strength of concrete, etc. , with one another. So it is necessary to make further research. In order to prevent the compression failure of concrete strut happening before the failure of stirrup yield and avoid brittle failure, the relations of minimum angle between strut and tie with the ratio of web reinforcement, the yield strength of stirrup reinforcement and the compress strength of concrete are deduced and some significant conclusions are got.