T形钢管混凝土组合柱—钢筋混凝土梁边节点抗震性能研究

发布时间：2018-08-20 15:43

【摘要】：钢管混凝土异形柱结构在钢筋混凝土异形柱结构的基础上发展而来,其最大的优点在于:利用外包钢管提高核心混凝土的承载能力及延性,解决普通钢筋混凝土异形柱结构无法在多高层建筑以及高抗震设防烈度地区应用的缺陷,同时兼具有普通异形柱可与墙体等厚、柱脚不突出墙面的优势,具有广阔的发展前景。近年来国内外学者对于钢管混凝土异形柱梁柱节点研究较少,且均侧重于异形柱与钢梁连接节点,对于钢管混凝土异形柱与钢筋混凝土梁的连接形式以及此类节点的受力与抗震性能研究尚未见诸报道。本文在2012年湖北省自然科学基金项目(2012FFB05112)和2014年中央高校基本科研业务费专项资金项目(WUT2014-IV-125)的资助下及课题组已有研究成果的基础上,设计制作T形钢管混凝土组合柱-钢筋混凝土梁外伸端板连接节点和加强环筋连接节点。采用试验研究、有限元数值模拟和理论分析相结合的方法,研究两类节点的受力性能和抗震性能,主要研究内容及成果概括如下:(1)以牛腿长度、端板厚度、高强螺栓直径、设置加强肋与否、环筋直径和环筋的设置方式为主要变化参数,按照1:2的缩尺比例,制作了10个外伸端板连接节点和7个加强环筋连接节点试件。通过静力试验和低周往复加载试验,探讨了节点的破坏形态和内力传递机理,并分析节点试件的荷载-位移滞回曲线、骨架曲线、位移和梁柱相对转角延性以及耗能性能等力学特性。通过试验参数分析,确定了各影响因素对节点承载力及耗能能力的影响程度,进而提出了节点设计建议和构造措施。试验结果表明,两类节点传力路径明确,破坏形式均为混凝土梁上牛腿外端塑性铰破坏;各试件滞回曲线饱满,外伸端板连接节点曲线呈倒S形,等效粘滞阻尼系数eh介于0.147~0.176,位移延性系数??介于3.48~6.29;加强环筋连接节点曲线呈弓形,eh介于0.199~0.262,??介于2.88~4.51;两类节点最大剪切角介于相对极限转角的0.796%~4.488%之间,节点域剪切变形对结构变形的影响几乎可以忽略不计;节点具有良好的抗震能力。(2)对实测节点试件的骨架曲线和滞回曲线进行分析、拟合,采用去量纲化方法建立了两类节点的恢复力模型,该模型由三折线骨架曲线模型、刚度退化规律和滞回准则构成。将实测骨架曲线、滞回曲线与建立的恢复力模型曲线进行对比,证明了本文确立的节点恢复力模型的正确性。(3)运用非线性有限元软件ABAQUS模拟分析单调加载和往复加载作用下节点的受力性能和抗震性能,并将计算结果与试验数据进行对比,以验证有限元模型的合理性;通过对节点的工作机理和应力分布特征进行分析,揭示了节点的裂缝开展过程及剪应力变化规律,在此基础上,考察了轴压比、梁柱线刚度比、框架梁混凝土强度等级和框架梁配筋率对节点力学性能的影响。分析结果表明,梁端荷载-位移曲线的模拟计算值与试验值吻合较好;节点剪力主要由核心区形成的斜压杆来承载,牛腿腹板承担的比例较少;设置加劲肋可有效抑制端板撬曲变形,降低节点区应力集度;梁端荷载达到极值时,加强环筋连接节点牛腿翼缘外侧1/3梁高范围内钢管壁存在明显鼓曲截面,可采用对此范围内钢管进行局部加厚以补强节点;轴压比及梁柱线刚度比对节点承载力较小,但增大线刚度比节点初始刚度出现了一定程度降低;提高框架梁混凝土强度等级,两类节点承载力均有所提高,其中,加强环筋连接节点表现得更为显著;节点抗弯承载力均随着配筋率的提高显著增大,但当框架梁配筋率超过1.8%后,承载力提高的幅值很小。(4)在试验和理论研究的基础上,考虑端板厚度、螺栓直径及加劲肋对节点连接处抗弯承载力的影响,建立了确定高强螺栓型号和端板尺寸的计算公式;通过对两类节点核心区的内力传递机理进行分析,给出了节点水平剪力的计算方法;充分考虑轴向压力、高强螺栓预应力和翼缘部分混凝土的影响,建立了两类节点核心区抗剪承载力计算公式,并与相关文献的试验数据进行了对比,结果显示承载力计算值和试验值能很好吻合。研究成果将为编制异形钢管混凝土结构技术规程提供试验依据和理论支持。在总结全文工作的基础上,提出了本课题研究展望。
[Abstract]:Concrete filled steel tubular special-shaped column structure is developed on the basis of reinforced concrete special-shaped column structure. Its greatest advantages are: the use of outer steel tube to improve the bearing capacity and ductility of core concrete, to solve the common reinforced concrete special-shaped column structure can not be used in high-rise buildings and high seismic fortification area defects, at the same time. In recent years, scholars at home and abroad have little research on the beam-column joints of concrete filled steel tubular special-shaped columns, and all of them focus on the connection between special-shaped columns and steel beams. For the connection form of concrete filled steel tubular special-shaped columns and reinforced concrete beams, as well as In this paper, T-shaped concrete-filled steel tubular composite columns are designed and manufactured with the support of Hubei Natural Science Foundation in 2012 (2012 FFB05112) and China Central University Funding Project (WUT2014-IV-125) in 2014. The experimental study, finite element numerical simulation and theoretical analysis are combined to study the mechanical and seismic performance of the two types of joints. The main research contents and achievements are summarized as follows: (1) With the length of corbel, the thickness of end plate, the diameter of high-strength bolts, the reinforced ribs are set. Whether it is or not, the diameter of ring bars and the setting mode of ring bars are the main parameters. According to the scale of 1:2, 10 joints with extended end-plate and 7 joints with reinforced ring bars are manufactured. Hysteresis loops, skeleton curves, displacements, relative angular ductility of beams and columns, and energy dissipation performance are studied. The influence degree of each factor on the bearing capacity and energy dissipation capacity of the joints is determined by the analysis of test parameters. The design suggestions and construction measures of the joints are put forward. The hysteretic curves of the specimens are full, the joints of the extended end-plate are inverted S-shaped, the equivalent viscous damping coefficient EH is between 0.147 and 0.176, and the displacement ductility coefficient is between 3.48 and 6.29; the joints of the reinforced annular bars are arched, EH is between 0.199 and 0.262, and EH is between 2.88 and 4.51; the two types of joints are the most common. The large shear angle ranges from 0.796% to 4.488% of the relative ultimate rotation angle, and the influence of shear deformation in the joint domain on the structural deformation can be neglected. The joints have good seismic resistance. (2) The skeleton curve and hysteretic curve of the tested joints are analyzed and fitted, and the restoring force models of the two types of joints are established by using the de-dimensionalization method. The model is composed of three-fold skeleton curve model, stiffness degradation law and hysteretic criterion. The measured skeleton curve and hysteretic curve are compared with the established restoring force model curve, which proves the correctness of the proposed joint restoring force model. (3) Monotonic loading and cyclic loading are simulated and analyzed by nonlinear finite element software ABAQUS. Comparing the calculated results with the experimental data to verify the rationality of the finite element model; through the analysis of the working mechanism and stress distribution characteristics of the joints, the crack development process and shear stress variation law of the joints are revealed. On this basis, the axial compression ratio, beam-column ratio are investigated. The results show that the load-displacement curves at the end of the beam are in good agreement with the experimental values; the shear force of the joints is mainly supported by baroclinic bars formed in the core area, and the ratio of bracket webs is small; stiffening ribs can be effective. It can restrain the end-plate prying deformation and reduce the stress concentration in the joint area; when the load at the end of the beam reaches the extreme value, the steel tube wall of the reinforced ring-bar connection joint has obvious buckling section within the height of 1/3 beam of the outer flange of the corbel flange, and the steel tube can be partly thickened to reinforce the joint; the axial compression ratio and the beam-column stiffness ratio are smaller than the bearing capacity of the joint, but the beam-column stiffness ratio is lower. The increase of linear stiffness decreases to a certain extent compared with the initial stiffness of the joints; the increase of concrete strength grade of the frame beam improves the bearing capacity of the two types of joints, especially the reinforced ring-bar joints; the bending capacity of the joints increases significantly with the increase of reinforcement ratio, but when the reinforcement ratio of the frame beam exceeds 1.8%, the bearing capacity of the joints increases. (4) On the basis of experimental and theoretical research, considering the influence of end plate thickness, bolt diameter and stiffener rib on the bending capacity of the joint, the calculation formulas for determining the type of high-strength bolt and the size of end plate are established; the internal force transfer mechanism in the core area of the two types of joints is analyzed, and the joint level is given. Considering the influence of axial pressure, high strength bolt prestressing and flange concrete, the shear bearing capacity formulas of two kinds of joint core area are established and compared with the experimental data of related literature. The results show that the calculated values of bearing capacity and the experimental values are in good agreement. The research results will be used to compile special-shaped joints. The technical specification of concrete filled steel tubular structure provides experimental basis and theoretical support.
【学位授予单位】：武汉理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU398.9;TU352.11

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