基于能量守恒理论的带肋钢筋-混凝土粘结滑移本构关系研究

针对钢筋-混凝土粘结滑移的劈裂破坏模式,将整个破坏过程分为未开裂的弹性阶段和带裂缝阶段。弹性阶段采用弹性厚壁圆筒模型,带裂缝阶段采用考虑混凝土软化特性的厚壁圆筒模型。基于这两种模型,研究了粘结滑移劈裂破坏过程的能量变化规律,推导出了两种模型的能量计算公式。利用能量守恒定律建立了钢筋-混凝土粘结滑移本构关系的微分方程,并通过数值积分方法得到了粘结滑移本构模型。该本构模型能够体现混凝土与钢筋材料参数和几何参数的影响,对不同形状的粘结滑移关系曲线具有较好的适应性。最后,将得到的本构关系与文献的试验结果进行对比,并分析了各参数的变化规律。

Bond-slip constitutive model between ribbed steel bars and concrete based on the conservation law of energy

This paper concentrates on analytical solution of local bond stress-slip relationship between ribbed steel bars and concrete corresponding to the splitting model of bond failure.The uncracked process of concrete splitting in the cover depth is divided into elastic stage and cracked stage.The thick-walled cylinder model is used for the initial elastic stage,while the cracked thick-walled cylinder model with softening behaviour of concrete is applied for the latter cracked stage.The energy equation of the two models is presented and the variation characteristic of energy during the process of splitting is discussed.Based on the energy conservation law,the differential equation accounting for bond stress-slip relationship is derived,which is used to obtain the local bond stress-slip relationship by numerical integration.The model shows good agreement with the available experimental results and accounts for the parameters of concrete and steel,which influence the local bond stress-slip response as observed in the experiment.Finally,the theoretical and the experimental results are compared and analysed.