柱中抬升式自复位摇摆钢框架结构滞回性能研究

HYSTERETIC BEHAVIOR OF SELF-CENTERING ROCKING STEEL FRAME STRUCTURE WITH LIFTING IN THE MIDDLE OF COLUMN

  • 摘要: 提出了一种新型的柱中抬升式自复位摇摆钢框架(SCRSF-CMU),旨在提高柱脚抬升式自复位摇摆钢框架(SCRSF-CBU)的恢复能力和抗震性能。SCRSF-CMU的摇摆节点位于底层柱的中部,采用可更换的锥形钢棒阻尼器(WHPs)作为耗能元件。为研究SCRSF-CMU的滞回性能,对一榀三层单跨的SCRSF-CMU试件进行了拟静力试验。随后,利用有限元软件ABAQUS建立了试件的多尺度有限元模型并验证了其准确性。建立了19个有限元模型,分析了主要设计参数对自复位摇摆钢框架滞回性能的影响。结果表明:SCRSF-CMU通过摇摆节点的抬升和自复位机制,将结构损伤集中于可更换的WHPs,其余构件保持弹性状态,2.5%顶层侧移角下具有可忽略的残余变形;与SCRSF-CBU相比,SCRSF-CMU具有更高的初始刚度、屈服后刚度、承载能力、变形能力和耗能能力;摇摆节点位置的变化对自复位摇摆钢框架的变形模式无影响;钢绞线的初始预拉力显著影响SCRSF-CMU的初始刚度、承载力、复位能力和相对能量耗散比,但对单圈循环耗能和屈服后刚度无影响;WHPs钢棒的数量、长度和直径对SCRSF-CMU的初始刚度和摇摆框架抬升力无影响,但显著影响其屈服后刚度、极限承载力、单圈循环耗能和相对能量耗散比。为避免SCRSF-CBU出现整体抬升,并确保其在实际应用中具备良好的自复位能力和耗能性能,自复位率应在1.0~1.5。

     

    Abstract: A novel self-centering rocking steel frame with lifting in the middle of column (SCRSF-LMC) is proposed to enhance the recovery capability and seismic performance of the self-centering rocking steel frame with column base lifting (SCRSF-CBL). The rocking joint of SCRSF-LMC is located in the middle of the bottom column and utilizes replaceable web-hourglass-shaped steel pins (WHPs) as energy dissipation elements. To investigate the hysteretic behavior of SCRSF-LMC, a quasi-static test was conducted on a three-story, single-span SCRSF-LMC specimen. Subsequently, a multi-scale finite element model of the specimen was established by using the finite element software ABAQUS and its accuracy was verified. Nineteen finite element models were established to analyze the impact of key design parameters on the hysteretic behavior of the self-centering rock steel frame. The results indicate that SCRSF-LMC, through the uplifting and self-centering mechanism of the rocking joint, concentrates structural damage on the replaceable WHPs, with other components remaining elastic and exhibiting negligible residual deformation under a roof drift ratio of 2.5%. Compared with SCRSF-CBL, SCRSF-LMC demonstrates higher initial stiffness, post-yield stiffness, load-bearing capacity, deformation capacity and energy dissipation capability. The change of rocking joint position has no effect on the deformation mode of the self-centering rocking steel frame. The initial prestress of steel strands significantly affects the initial stiffness, load-bearing capacity, self-centering capability and relative energy dissipation ratio of SCRSF-LMC but has no impact on single-loop energy dissipation or post-yield stiffness. The number, length and diameter of WHP steel pins do not affect the initial stiffness and uplift force of the rocking frame in SCRSF-LMC, but significantly influence post-yield stiffness, ultimate load-bearing capacity, single-loop energy dissipation and relative energy dissipation ratio. To avoid the global uplift of SCRSF-LMC and ensure good self-centering and energy dissipation performance in practical applications, the self-centering rate should be between 1.0 and 1.5.

     

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