局部替换ECC板柱节点抗冲切性能研究

STUDY ON PUNCHING SHEAR RESISTANCE OF SLAB-COLUMN CONNECTIONS WITH PARTIAL ECC REPLACEMENT

  • 摘要: 为探讨局部替换工程水泥基复合材料(Engineered Cementitious Composite, ECC)板柱节点的冲切性能,该研究对2个具有不同ECC替换面积的RC板柱节点以及1个普通RC板柱节点进行拟静力加载。试验结果表明:采用ECC局部替换可以显著提高RC板柱节点的延性,使其破坏由脆性冲切破坏转变为弯冲破坏。此外,通过数值分析进一步讨论了ECC替换面积、板厚和ECC抗压强度对板柱节点抗冲切性能的影响。数值分析结果表明,当取ECC替换长度为距离柱表面1倍板厚时,可以使RC板柱节点的抗冲切承载力及变形能力分别提高42%和227%。然而,当替换长度进一步增加时,试件的抗冲切承载力及变形能力提高幅度不大。因此,建议采用的ECC替换长度为距离柱表面1倍板厚。增加板厚可以显著提高板柱节点的抗冲切承载力及初始刚度,而ECC抗压强度的提高对其影响不大。

     

    Abstract: To study the punching shear resistance of slab-column connections with partial engineered cementitious composites (ECC) replacement, two connections with different replacement areas and one RC connection were tested under quasi-static loading. The test results indicate that partially replaced concrete with ECC can significantly increase the ductility of the connection and convert the failure mode from punching shear failure to flexural-punching failure. Moreover, numerical analyses were conducted to investigate the effects of replacement area, slab thickness and compressive strength of ECC on the punching shear resistance of slab-column connections. The results demonstrate that when the ECC replacement length is one times the slab thickness from the column surface, the punching shear resistance and deformation capacity can be increased by 42% and 227%, respectively. However, further increasing the replacement length can only slightly increase the punching shear resistance and deformation capacity of the connections. Thus, the replacement length is suggested to be one times the slab thickness from column surface. Increasing the slab thickness can significantly improve the punching shear resistance and initial stiffness of slab-column connections while the increase of ECC compressive strength has little effect on it.

     

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