Y型双肢连梁偏心支撑组合框架力学性能试验研究

EXPERIMENTAL STUDY ON MECHANICAL PROPERTY OF THE Y-ECCENTRICALLY BRACED STEEL-CONCRETE COMPOSITE FRAME WITH DOUBLE SHEAR LINKS

  • 摘要: 传统的Y型单肢连梁偏心支撑组合框架(简称“SY-EBCF”)已被证明是一种高效的消能减震结构体系;但连梁的引入会压缩建筑空间,降低建筑功能;该文在SY-EBCF形式的基础上,提出了Y型双肢连梁偏心支撑组合框架(简称“DY-EBCF”)通过增加连梁数目,减小连梁尺寸,既能保证偏心支撑能够提供足够的承载力和刚度,又能最大限度的降低连梁对下部空间的占用。为研究DY-EBCF的力学性能,该文分别对一个DY-EBCF试件和拆卸失效连梁后的试件开展了拟静力试验,分析了试件的失效模式、荷载-位移曲线和关键截面应变分布。试验结果表明:连梁主要依靠腹板剪切变形耗散能量,在其失效退出工作前,DY-EBCF试件的滞回曲线饱满且稳定;当拆除失效连梁后,结构在不平衡内力作用下恢复到原位,残余变形角为0.002 rad,小于连梁可更换的最大残余位移角(0.003 rad);余下的组合框架部分水平承载力虽降低至未拆卸连梁时的1/2,但结构仍具有稳定承载的能力。最后对比了DY-EBCF和SY-EBCF的试验结果,证明了DY-EBCF在耗能能力、刚度和变形能力方面具有更好的抗震性能。

     

    Abstract: The traditional Y-eccentrically braced steel-concrete composite frame with single shear link (SY-EBCF for short) has been proven to be an effective energy dissipation structure system. However, the introduction of shear link will significantly compress the building space and reduce the building function. Based on the SY-EBCF, the Y-eccentrically braced steel-concrete composite frame with double shear links (DY-EBCF for short) is proposed in this paper, which can ensure sufficient bearing capacity and lateral stiffness of the eccentric brace system while minimizing the occupation of shear link on the lower space by increasing the number of shear link and reducing the size of shear links. In order to investigate the mechanical property of DY-EBCF, the cyclic loading tests of a DY-EBCF specimen and a specimen with damaged link removed were carried out. The failure mode, load-displacement curve and the strain distribution of key cross-section were obtained. The test results indicate that the shear link mainly relies on shear deformation of the web plate to dissipate energy, and the structure has stable hysteresis and excellent energy dissipation before shear link fails. When the damaged link is removed, the structure is able to return to its un-deformed original position under the action of unbalanced internal forces. The residual drift angel of 0.002 rad is less than the maximum residual drift angle of replacing shear link (0.003 rad). Although the lateral bearing capacity of the residual composite frame decreases to 1/2 of that of DY-EBCF, the structure still has stable load-bearing capacity. Finally, the test results of DY-EBCF and SY-EBCF were compared, showing that DY-EBCF has better seismic performance in terms of energy dissipation, stiffness and deformation capacity.

     

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