中文摘要：

通过自行设计的装置测量了高温后粘结问题中的化学胶结力和摩擦系数,得出了它们随温度经历的变化规律。利用测得的基础参数定义了钢筋与混凝土界面的弹塑性库仑摩擦准则并将其植入有限元模型;采用面-面接触的接触单元模拟混凝土与钢筋界面的力学行为。模型通过对钢筋肋的显式离散实现了钢筋肋与混凝土间机械咬合作用的模拟。数值结果和试验数据的对比表明,该文提出的模型可以较好的模拟高温后带肋钢筋和混凝土之间的粘结滑移。最后,利用有限元模型对400℃温度经历拔出过程中的应力分布及裂缝的扩展进行了细致的研究。

英文摘要：

The chemical adhesive and friction coefficient of the bond between concrete and reinforcing steel in high-strength concrete after exposure to high temperatures was measured by a self-designed setup, and their variation with elevated temperatures has been obtained. Using the measured parameters, the elastic plastic Coulomb-type friction criterion is defined, and is used in 3D FEM modelling. Surface-to-surface contact elements are employed for the mechanical properties of the concrete-to-bar interface. The mechanical interlock between steel bar ribs and concrete has been modelled by means of an explicit discretization of the bar ribs. The comparison between numerical results and experimental data shows that the model proposed in this paper can be used to simulate the bond slip between the steel bars and concrete after elevated temperatures. Finally, the stress distribution and crack propagation during the pull-out process in concrete which has experienced 400°C temperatures have been studied in detail.