钢筋桁架补强再生混凝土梁受力性能研究

RESEARCH ON MECHANICAL PERFORMANCE OF REINFORCED RECYCLED CONCRETE BEAM WITH STEEL-BAR TRUSS

  • 摘要: 回收混凝土中的虚渣缺陷及其随机分布会影响结构性能,使再生混凝土难以用于上部结构建造。该文研究通过加设特定的构造钢筋,将普通梁的钢筋笼改造成桁架结构,使钢筋桁架具有适宜的承载力及刚度,可以用来弥补再生混凝土材料性能缺陷可能造成的不利影响。分别采用传统绑扎钢筋笼与专门设计的焊接桁架钢筋笼、普通混凝土与再生混凝土,制作了混凝土梁试件,进行受弯性能试验,研究了承载力、裂缝规律、破坏形态、延性系数等差异;并通过理论分析,得出了具有一般性的钢筋桁架补强再生混凝土梁的设计方法;建立试验梁的有限元模型与试验结果对比分析。研究表明,借助钢筋桁架,再生混凝土梁的正截面抗弯承载力可提高至同截面普通混凝土梁;刚度可根据需求加强至不低于同截面普通混凝土梁;有限元分析与试验结果吻合较好,试验研究反映的规律具有一般性。施工方法与传统混凝土结构相同,不增加特殊材料及工种,工程实施方便,能显著节约混凝土回收及再生骨料加工的成本。

     

    Abstract: The defects and their random distribution in recycled concrete will affect the performance of the structure and make it difficult for recycled concrete to be used in superstructure construction. In the study, the steel cage of ordinary beams is transformed into a truss structure by adding specific structural steel bars. The steel-bar truss has appropriate bearing capacity and stiffness, which can be used to make up for the adverse effects caused by the performance defects of recycled concrete materials. The specimens of concrete beams were made by traditional binding reinforcement cage, specially by designed welded truss reinforcement cage, by ordinary concrete and recycled concrete, and the flexural performance tests were carried out to study the differences in bearing capacity, in crack development, in failure pattern and, in ductility coefficient. Through theoretical analysis, the general design method of reinforcing recycled concrete beam with steel-bar truss was obtained. The finite element models of the test beams were established to compare with the test results. The results show that the flexural capacity of recycled concrete beams can be improved to that of ordinary concrete beams with the same section by means of steel-bar truss. The stiffness can be strengthened to no less than that of the ordinary concrete beam of the same section according to the demand. The finite element analysis results are in a good agreement with the experimental results, and the laws reflected in the experimental research are general. The construction method is the same as the traditional concrete structure, no special materials and types of work are added, and the project is convenient to implement, can significantly save the cost of concrete recovery and recycled aggregate processing.

     

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