The paper presents and discusses the results of a numerical study on post-fire (residual) behavior of reinforced concrete (RC) beams with critical tension lap splices. It is based on the experimental findings and the validation of the numerical approach in the accompanying paper and further analyzes the residual performance by varying most influencing parameters such as bond length, fire duration and concrete cover to the spliced reinforcing steel. Three-dimensional numerical (FE) analysis is performed employing the temperature dependent microplane model for concrete in the framework of the smeared crack approach. The numerical results show that the exposure to fire can change the strength hierarchy of the flexural member such that the splice lengths required to develop the bar under ambient (unheated) conditions may not be sufficient to develop the bar in residual (post-fire) conditions due to the preceding bond splitting failure. It is further found that increased concrete cover does not significantly enhance the post-fire flexural capacity. In closing, a design concept for the determination of the required bond length in case of fire loads is presented.

本文介绍并讨论了带有临界拉力搭接的钢筋混凝土（RC）梁火灾后（残余）行为的数值研究结果。它基于实验结果和随附论文中数值方法的验证，并通过改变大多数影响参数（例如粘结长度，防火时间和拼接钢筋的混凝土覆盖层）来进一步分析残余性能。在涂抹裂缝方法的框架内，采用温度依赖的微平面模型对混凝土进行三维数值（FE）分析。数值结果表明，暴露于火中可以改变抗弯构件的强度等级因此，由于先前的键断裂失败，在环境（未加热）条件下开发钢筋所需的接头长度可能不足以在残余（后火）条件下开发钢筋。进一步发现，增加的混凝土覆盖层不会显着增强火灾后的挠曲能力。最后，提出了一种设计概念，用于确定火灾荷载下所需的粘结长度。