Mesoscale simulation of compression-induced cracking and failure of ASR-damaged concrete with stirrup confinement
Mesoscale simulation of compression-induced cracking and failure of ASR-damaged concrete with stirrup confinement
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DOI：
10.1016/j.engfracmech.2022.108977
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发表时间：
2023-01
影响因子：
5.4
通讯作者：
Jie Luo;S. Asamoto;K. Nagai
中科院分区：
文献类型：
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作者：
Jie Luo;S. Asamoto;K. Nagai
碱-硅反应（ASR）是一种耐久性问题，可导致混凝土结构的膨胀和开裂。ASR损伤影响混凝土本身的物理特性，尽管钢筋混凝土结构的承载能力可以保持，因为钢筋继续限制核心混凝土。然而，如果膨胀损伤和外部载荷的联合作用导致钢筋断裂，这将损害结构的安全性。为了研究这一现象，离散数值模拟方法3D RBSM被用来进行参数研究约束下的三个ASR损伤水平的混凝土的压缩破坏。研究了具有正常屈服强度和弹性性能的箍筋。提出并讨论了不同约束条件下混凝土的ASR膨胀和开裂行为。在此基础上，研究了含ASR损伤混凝土的受压破坏及约束效应。模拟的应力-应变关系的情况下，没有ASR损伤很好地拟合的理论预测模型。至于弹性模量和抗压强度，它往往随着ASR膨胀的增加而降低，无论约束条件如何。对于箍筋约束的模型，抗压强度的退化被延迟。从模拟中得到了内部应力、混凝土裂缝扩展和应变发展的可视化结果，并对这些进行了讨论。结果表明，弹性箍筋的约束效应大于正常屈服强度箍筋的约束效应。进一步提取了试验中难以监测的箍筋内外表面应变分布。应力集中出现在内半径的弯曲，这是一致的观察真实的结构，并可能导致在这些位置的破裂。
The alkali-silica reaction (ASR) is a durability concern that can lead to expansion and cracking of concrete structures. ASR damage affects the physical characteristics of the concrete itself, although the load-carrying capacity of an RC structure may be maintained because the reinforcement continues to confine the core concrete. However, if the combined effect of expansion damage and external loading were to result in reinforcement rupture, this would prejudice the safety of a structure. To study this phenomenon, the discrete numerical simulation method 3D RBSM is used to carry out a parametric study of the compressive failure of concrete with three ASR damage levels under confinement. Stirrups with normal yield strength and with elastic behavior are investigated. The ASR expansion and cracking behavior for concrete with different confinement scenarios are presented and discussed. Following that, the compressive failure of concrete with ASR damage and the effect of stirrup confinement are studied. The simulated stress–strain relationships for cases without ASR damage are well fitted by a theoretical prediction model. As for elastic modulus and compressive strength, it tends to decrease with increasing ASR expansion whatever the confinement conditions. For models confined by stirrups, the degradation of compressive strength is delayed. Visualizations of internal stress, concrete crack propagation and stirrup strain development are obtained from the simulations and these are discussed. It is found that the confinement effect of elastic stirrups is greater than that of stirrups with normal yield strength. Further, the strain distribution on inner and outer surfaces of stirrups which is hard to be monitored in experiments is extracted. Stress concentrations arise at the inner radius of the stirrup bends, which is consistent with observations of real structures and could lead to rupture at these locations.