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在钢筋混凝土结构中,已存在裂缝对新裂缝的产生和发展有影响,从而对结构承载力性能亦有影响。为研究三维情况下裂缝交叉扩展的机理及其对结构承载力性能的影响,该文设计截面为正六边形对称配筋的钢筋混凝土梁实验,通过变换加载面和加载方式使梁分别产生竖直方向贯通的弯曲裂缝以及两种方向的剪切斜裂缝,并使各裂缝在空间相互交叉。通过实验,观察三维多向裂缝交叉扩展过程,测量梁各阶段荷载-挠度曲线,最后分析裂缝交叉扩展相互作用机理及其对梁构件承载力的影响的基本规律。针对多向裂缝相互作用机理建立三维多向固定裂缝模型,数值模拟结果表明该模型能够模拟多向裂缝交叉情况及其相互作用影响。
In reinforced concrete structures, existing cracks have an impact on the occurrence and development of new cracks, and thus also affect the structural bearing capacity. In order to study the mechanism of crack propagation in three-dimensional case and its influence on the bearing capacity of the structure, this paper designs a reinforced concrete beam with a regular hexagonal symmetrical reinforcement. The beam is generated vertically by changing the loading surface and the loading method Directional through cracks and oblique shear cracks in both directions, and to make the cracks cross each other in space. Through experiments, the cross-expansion process of three-dimensional multi-directional cracks was observed, and the load-deflection curves at various stages of the beam were measured. Finally, the mechanism of the interaction between cracks and cross-spreading was analyzed and the basic rules of the influence on the bearing capacity of beam members were analyzed. A three-dimensional multi-directional fixed fracture model is established for the mechanism of multi-directional fracture interaction. The numerical simulation results show that the model can simulate the multi-directional fracture cross-over and its interaction effects.