钢筋粘结滑移的理论模型分析

Anaylsis of Theoretical Model About Bonding Slide of Reinforcing Bars

将化学胶合力、摩擦力和机械咬合力等所构成的粘结强度简化为初始粘结应力和随粘结滑移增长的摩擦应力之和,并且将摩擦应力的非线性变化采用双直线滑移曲线表达。将钢筋锚固长度的粘结强度发挥程度划分为塑性段与弹性段,应用荷载传递函数方法与钢筋滑移的连续条件建立粘结滑移本构模型。剪切变形系数Cz、初始粘结应力τ0与粘结应力的增长率ξ等计算参数采用复形优化方法拟合确定。与试验数据对照,可以较好地反映粘结强度的发展与分布规律。

The bond strength on the interface between bar and concrete, which includes the chemical cement composite force, frictional stress and mechanical joining-up stress, is simplified as tow parts that are the initial bond stress and generalized frictional stress, respectively. The generalized frictional stress, which its characteristic is non-linear, is showed as bilinear. Because of anchorage length of bar being divided into elastic part and plastic part based on bond strength, the method of load transfer function and continuous condition of bar slipping are applied into creating bond-slip constitutive model. The calculation parameters of model equation, such as shearing deformation coefficient Cz, initial bond stress τ0 and rate of increase ξ of bond stress, are obtained with SPL fit. As compared with date of bar drawing test, the bond-slip constitutive model could well fit developing and distributing law of bond-strength.