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重复荷载下粘结滑移本构关系是结构疲劳计算和有限元分析的基本关系之一。该文通过23个试件静载和重复荷载下的拉拔试验对钢筋滑移量、粘结滑移基本关系、粘结应力形状函数、粘结疲劳破坏准则进行了全面深入的研究。首先根据加载端峰值滑移量和残余滑移量发展规律得出了计算公式;接着利用粘结滑移变化规律提出了考虑残余滑移、应力水平和循环荷载次数的幂函数形式粘结本构关系;运用沿钢筋埋长范围内应变变化得出了疲劳破坏三阶段粘结应力形状函数;最后基于重复荷载下发生粘结疲劳破坏的条件是滑移量增加到静载下的最大滑移量的基本准则,理论推导了粘结疲劳寿命方程。研究表明:当粘结疲劳没有发生时,重复荷载下极限粘结强度及最大滑移量并不受重复次数的影响。研究结果为理论分析重复荷载下受弯构件裂缝宽度、锚固长度、刚度、塑性铰转动问题等提供了依据和方便。
The constitutive relation of bond-slip under repeated load is one of the basic relationships between structural fatigue and finite element analysis. In this paper, a comprehensive and in-depth study of the sliding displacement of steel bars, the basic relation of bond slip, the shape function of bond stress and the failure criterion of bond fatigue are carried out through the drawing tests of 23 specimens under static load and repeated load. Firstly, the formula of peak-slip and residual slippage at load side is derived. Then, the power function formal bond structure considering the residual slip, stress level and cyclic load is proposed by using the variation law of bond slip. The relationship between the three types of fatigue stresses and the shape of the three-stage bond is obtained by using the strain changes along the length of the bar. Finally, the maximum slip under the static load is obtained based on the condition of the bond fatigue failure under repeated load The basic principle, the theory derived bond fatigue life equation. The results show that the ultimate bond strength and the maximum slip under repeated load are not affected by the number of repetitions when the bond fatigue does not occur. The results provide the basis and convenience for theoretical analysis of the crack width, anchorage length, stiffness and plastic hinge rotation problems of flexural members.