钢桁腹杆—劲性骨架混凝土组合节点受力性能研究

发布时间：2018-02-28 07:26

本文关键词： 钢桁腹杆-劲性骨架混凝土组合节点位置系数极限承载力剥落荷载　出处：《福州大学》2014年硕士论文　论文类型：学位论文

【摘要】：钢管混凝土K型节点在弦杆上外包钢筋混凝土后形成的便是钢桁腹杆-劲性骨架混凝土组合节点(钢管混凝土弦杆外包混凝土即为钢管混凝土劲性骨架组合柱)。为了了解这种新型组合节点的受力性能,以及与钢管混凝土K型节点在受力性能方面的异同点,本文以位置系数(弦杆外径与弦杆外包混凝土总厚度之比)为主要参数,以节点外包混凝土剥落荷载和节点极限承载力为研究对象,开展了这种节点的参数试验和有限元分析,并进行了合理位置系数取值以及节点承载力理论公式的研究。主要工作和结论有以下几个方面：(1)进行了组合节点与钢管混凝土K型节点的对比试验。试验结果表明,在腹杆与弦杆外径比相同的前提下,组合节点在外包混凝土开裂后,其最终破坏模式与钢管混凝土K型节点相同；与钢管混凝土K型节点相比,组合节点极限承载力提高较小,提高幅度约5.8%左右。(2)以位置系数为参数进行了组合节点受力全过程的试验。试验结果表明,位置系数的变化主要影响外包混凝土的初裂荷载和剥落荷载,位置系数越大,外包混凝土的初裂荷载和剥落荷载越小,组合节点在外包混凝土破坏开裂后均表现为钢管混凝土K型节点破坏模式。(3)采用有限元软件ABAQUS建立了组合节点的有限元模型,与试验结果进行比较并验证有限元模型的正确性。通过参数分析得到,位置系数、箍筋配筋率、箍筋加密区长度和外包混凝土强度等参数影响外包混凝土的剥落荷载,对组合节点极限承载力影响很小；影响组合节点极限承载力的主要参数是腹杆与弦杆外径比。(4)在上述研究的基础上,以剥落荷载为优化目标,通过有限元参数分析,提出了劲性骨架外包混凝土位置系数建议值(约为0.50左右)；并在现有钢管混凝土K型节点计算公式的基础上提出了这种组合节点极限承载力的计算方法；最后利用现有规范以及本文试验和有限元的分析结果,提出组合节点构造建议。
[Abstract]:Concrete filled steel tube (CFST) K-type joints are formed after the reinforced concrete is wrapped on the chord, which is composed of steel truss web members and stiffened skeleton concrete joints (the concrete filled steel tube chords are concrete-filled steel tubular composite columns). In order to understand the mechanical behavior of this new type of composite joint, As well as the similarities and differences between the K-type joints of concrete-filled steel tube (CFST), the paper takes the location coefficient (the ratio of the outside diameter of the chord to the total thickness of the concrete of the chord) as the main parameter. Taking the exfoliation load and ultimate bearing capacity of the joints as the research object, the parameter tests and finite element analysis of the joints are carried out. The reasonable position coefficient and the theoretical formula of bearing capacity of joints are studied. The main work and conclusions are as follows: 1) the comparative tests between composite joints and concrete filled steel tubular K-joints are carried out. The experimental results show that, Under the same external diameter ratio of webs and chords, the ultimate failure mode of composite joints is the same as that of concrete-filled steel tubular (CFST) K-joints, and the ultimate ultimate bearing capacity of composite joints is smaller than that of CFST K-joints. The experimental results show that the change of the position coefficient mainly affects the initial crack load and the spalling load of the concrete, and the greater the position coefficient is, the greater the position coefficient is. The smaller the initial crack load and the spalling load, the smaller the failure mode of the composite joints is. (3) the finite element software ABAQUS is used to establish the finite element model of the composite joints. Comparing with the experimental results and verifying the correctness of the finite element model, the parameters such as the location coefficient, the ratio of stirrups reinforcement, the length of the infill zone of stirrups and the strength of the encased concrete affect the spalling load of the concrete. The main parameter affecting the ultimate bearing capacity of composite joints is the ratio of external diameter of web and chord. On the basis of the above research, the peeling load is taken as the optimization objective, and the finite element parameter analysis is carried out. The suggested value (about 0.50) of the location coefficient of the stiffened frame encased concrete is put forward, and the calculation method of the ultimate bearing capacity of the composite joint is put forward on the basis of the existing formulas for calculating the K-type joints of concrete-filled steel tubular (CFST). Finally, based on the existing codes and the experimental and finite element analysis results in this paper, some suggestions for the construction of composite joints are put forward.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU398.9

【相似文献】