【作者】 吴捷；

【导师】 吕志涛；

【作者基本信息】 东南大学 ， 结构工程， 2006， 硕士

【摘要】 圆钢管结构是一种具有优越结构性能、良好经济效益的大跨空间钢结构形式。它将结构和建筑协调统一起来,因此在近代各类大型标志性建筑中频繁亮相。圆管K形搭接相贯节点更因其耗钢量低、受力性能好、承载力大、工艺专业化等诸多优点日趋成为圆钢管结构中节点最主要形式之一。然而,理论往往滞后于实践。苏州国际博览中心工程设计中提出了一种新的圆钢管结构节点的形式,但是,其受力性能及设计方法,国内外均无研究。为此,本文从平面K形搭接节点入手,首次对一种新型节点——空间双钢管并联K形搭接节点进行了受力性能研究。同时,本论文专门针对搭接节点特有的内隐藏焊缝施焊与不焊两种情况作了对比分析,此在国内更无相关研究报道。本论文研究了平面K形搭接节点破坏模式的种类、几何参数对节点承载力的影响、内隐藏焊缝施焊与不焊的差异,利用非线性有限元方法计算了大量的节点模型并与现行国内外及相关文献公式计算结果作了对比,证实了支管搭接较之支管有间隙的节点的极限承载力有显著提高,通过节点数据回归,本文提出了一套反映节点参数特性的平面K形搭接节点承载力公式,公式中还考虑了内隐藏焊缝不焊的影响,具有一定的工程实用价值。在平面K形搭接节点研究的基础上,本论文选取相同的几何参数对空间双钢管并联K形搭接节点作了相应的破坏模式、参数影响、内隐藏焊缝等问题的研究,揭示了新型节点与平面K形搭接节点的相似性。将本论文提出的平面K形搭接节点极限承载力建议公式运用在新型节点上,得到了令人满意的吻合度,验证了“在考虑节点极限承载力时,将空间双钢管并联K形搭接节点简化为平面K形搭接节点”的可行性。本论文还介绍了5个空间双钢管并联K形搭接节点(内设加劲肋)足尺试验的受力全过程特点,进行了试验数据分析,证实了内隐藏焊缝不焊会产生使塑性区由支管搭接相贯区向支管跟部转移,同时使节点承载力下降的事实,为实际工程的正确设计提供了可靠的依据。并且试验数据验证了运用有限元分析手段的准确度和可行性。论文研究结果表明,K形搭接节点不同于传统间隙节点,破坏模式已由常见的主管管壁塑性破坏转变为以主支管局部联合塑性屈曲、支管局部塑性屈曲和焊缝断裂为主的破坏形式。因此,现行规范对此类节点的承载力计算公式有待修正。同时,对于搭接率大于60%的节点笔者建议尽量全周施焊,对于搭接率小于60%的节点内隐藏焊缝不焊时,则应依据建议公式作相应折减。更多还原

【Abstract】 Tubular structure is frequently applied in all kinds of large span structures in these days. It assorts with structure and architecture in a walk, provided with predominant structural capacity and satisfied ecnomy benefit. Overlap tubular K-joints are common features in tubular structures because of their low steel-consuming, excellent mechnics performance, large bearing capacity and special technics. Before long a new kind of tubular joints,called overlap parallel tubular K-joints, is appeared in Suzhou Internantional Expro Center, which has no theoretics to comply with. So, the mechnics performance study of uniplanar overlap tubular K-joints as a leadoff, a research of the new kind of joints is then presented for the first time. Meanwhile, Hidden weld effection is also analysed ,which is not available in the national investigation.Dearing the study of uniplanar overlap tubular K-joints, using a finite element (FE) study of axially loaded overlap tubular K-joints as a platform, a research on the distribution of the various modes of failure, an extensive, systematic parametric study and an analysis of the hidden weld effection are carried out in turn. The results indicate that the ultimate bearing capacity of overlap K-joints is obviously larger than the gap ones.Comparing with the current codes and design guidances, a equation predicting the strength Pu of overlap K-joints is developed, using nonlinear regression techniques. In the equation, the effection of hidden weld is also considered.Further more, the corresponding study of multiplanar overlap parallel tubular K-joints is proceeded, with the same parameters and ranges as those of uniplanar K-joints.The results of research disclosure the similarity between these two joint-forms. Applying the bearing capacity equation advanced above to multiplanar parallel one, shows a good accurate prediction (nonmember failure) of the FE data. So it is feasible to simplify a multiplanar pallel K-joints to two uniplanar K-joints, when the ultimate bearing capacity is what we want to know.Five full size parellel tubular K-joints model tests are fulfilled. The specimens are come from Suzhou Internantional Expro Center. The test procedure and data anlysis, especially the comparison between absence and presence of the hidden weld, are written up. Nonelinear finite element analysis (FEA) is also used to analyze the tested tubular joints. The coincidence of experiment data and FEA results shows the applicablilty of the finite-element study.From the research, it is found out that different from the tradional gap K-joints, the faliure modes of overlap K-joints include brace local buckling, combined chord wall bending and brace local buckling and weld break. The ultimate bearing capacity predicting fomular of the overlap K-joints in the current codes needs to be modified. When more than 60 percent weld of the overlap K-joints is considered to be absence of hidden weld, it is suggested to be whole welded, else should be reduced the bearing capacity according to the equation adivised above.更多还原