The confining effect of concrete cover and stirrups reduces the rate of bond deterioration due to corrosion. However, the large dispersion in recorded experimental data makes it difficult to clearly separate the influence of cover depth and stirrup confinement on bond degradation. This study utilises the discrete 3D Rigid Body Spring Model (RBSM) to conduct a meso-scale investigation regarding the effect of cover thickness and stirrup confinement on internal crack evolution and pull-out behaviour in corroded reinforced concrete models. The simulation scheme is divided into two stages. In stage 1, different degrees of corrosion are introduced, producing cracking in the cover concrete; in stage 2, the corroded main reinforcement is pulled out from the damaged concrete. 3D RBSM is advantageous because the concrete is randomly meshed to reduce mesh bias on crack propagation and the actual geometry of the deformed bars is modelled. The simulation results clarify that the presence of thicker cover delays crack initiation but increases the rate of crack opening. Stirrups do not have any significant effect on crack initiation but effectively restrict crack growth. An investigation of the internal stress in the simulation models shows that tensile stresses generated in stirrups during corrosion are responsible for reactionary confining pressure that restricts crack propagation. Load-displacement curves show reductions in pull-out capacity, stiffness and ductility with increasing corrosion damage. The relative influence of crack opening and stirrup volume on the rate of bond degradation with respect to average surface crack width are discussed and compared with published experimental results and an empirical equation.

混凝土保护层和箍筋的约束作用降低了由于腐蚀引起的粘结劣化率。然而，记录的实验数据中的较大分散使得难以清楚地区分覆盖深度和箍筋限制对键降解的影响。这项研究利用离散的3D刚体弹簧模型（RBSM）对覆盖层厚度和箍筋限制对锈蚀钢筋混凝土模型中内部裂纹演变和拉拔行为的影响进行了中尺度研究。仿真方案分为两个阶段。在第1阶段，引入了不同程度的腐蚀，使覆盖混凝土产生裂缝；在阶段2中，将腐蚀的主钢筋从损坏的混凝土中拉出。3D RBSM的优势在于，混凝土是随机网格化的，以减少裂纹扩展时的网格偏差，并且可以对变形钢筋的实际几何形状进行建模。仿真结果表明，较厚的覆盖层会延迟裂纹的萌生，但会增加裂纹的开口率。马ir对裂纹萌生没有明显影响，但有效地限制了裂纹的增长。在模拟模型中对内部应力的研究表明，在腐蚀期间在箍筋中产生的拉应力是限制裂纹扩展的反作用围压的原因。载荷-位移曲线表明，随着腐蚀破坏的增加，拉拔能力，刚度和延性降低。