【摘要】 受剪承载力计算是钢筋混凝土结构中最基本的理论和工程设计问题,但由于其机理复杂、影响因素众多,目前仍没有一种被普遍接受的抗剪理论和计算方法。基于修正斜压场理论(MCFT),考虑了斜裂缝之间混凝土拉应力对受剪承载力的影响,通过合理简化,得到混凝土斜压杆角度的显式计算公式。考虑了斜向开裂后混凝土斜压杆在拉压双轴受力状态下的本构关系,编制了有腹筋钢筋混凝土梁受剪承载力的计算程序。最后推导了有腹筋钢筋混凝土梁受剪承载力的简化计算公式,相比MCFT,无需查表或迭代计算。建立了209根钢筋混凝土矩形梁的剪切试验数据库,采用统计特征值法和影响因素分析法,对提出的显式MCFT、GB 50010—2010、JTG D62—2004、ACI318-08和CSA-04规范中的抗剪计算方法进行评估,结果表明显式MCFT的计算精度较高。更多还原

【Abstract】 Shear strength calculation method is the fundamental theory and practical design basis of reinforced concrete( RC) structures. Due to the complexity of shear failure mechanisms and a great quantity of influential factors,there has been none of existing theories widely accepted for the calculation of shear strength. First,based on MCFT,the expression for the inclination of concrete strut is explicitly derived,with the contribution of tensile stresses of concrete between the diagonal cracks considered. Furthermore,a program is developed to calculate the shear strength,with the consideration of the stress-strain relation of cracked concrete under biaxial stress state. However, the iterative computation is complicated and time-consuming. By combining the calculation of shear crack width with the relationship between the principle tensile strain and the strain of stirrups,a simplified explicit expression for shear strength is developed with no necessity of table look-up or iterative computations. A database is established for the shear tests of 209 RC rectangular beams,and it may be utilized to evaluate the proposed explicit MCFT as well as the methods in GB50010—2010,JTG D62—2004,ACI 318-08 and CSA-04 based on statistic eigenvalue method and analyzing method of influential factors. Results indicate that the shear strength computed by the explicit MCFT has a good agreement with the published experimental data.更多还原