共查询到18条相似文献,搜索用时 140 毫秒
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CCTV新台址主楼钢结构施工变形预调值计算的分阶段综合迭代法 总被引:12,自引:4,他引:12
CCTV新台址主楼两塔楼双向倾斜6°,顶部通过"L"形大悬臂相连,整体结构形成一个不规则的"空间门式"结构体系,具有"塔楼倾斜"、"空间连体"及"大悬臂"的构成特点。主楼钢结构安装采用无支撑胎架的施工方案,悬臂段合拢前两塔楼不断地向倾斜方向内侧独立变形,合拢后二者相互支撑,协调变形。施工过程中必须对两塔楼及大悬臂结构和构件的安装位形设置预调值,使其施工完成后的结构位形满足设计位形或目标位形的要求,否则成型位形将不满足设计及施工要求,甚至会导致大悬臂结构无法顺利安装。针对CCTV新台址主楼,提出一种精确计算其钢结构施工变形预调值的分析方法———分阶段综合迭代法。分析给出了结构在施工过程中的变形预调值,作为实际结构施工及安装的重要定位依据。 相似文献
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对于复杂大跨度空间钢结构,施工过程对成型后的结构受力状态影响较大。通过对施工力学模拟中常用分析方法的研究,提出采用节点修正生死单元法作为施工力学分析方法,采用节点修正正装迭代法确定变形预调值,并将该方法通过算例进行验证,继而应用于深圳湾体育中心钢结构的施工力学模拟中,理论计算结果与实际监测结果吻合较好。研究表明:节点修正生死单元法和节点修正正装迭代法限制了"死"单元的过大"漂移",可以很好的控制安装位形,计算精度良好,算法稳定,是结构施工力学分析和变形预调值分析的有效方法,适用于类似复杂大跨度空间钢结构的施工力学模拟。 相似文献
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《建筑钢结构进展》2020,(4):141-148
白浪河无轴式摩天轮采用创新的固定立体环状结构形式,其施工过程中风荷载和温度作用影响显著。为保障结构的施工安全和安装精度,采用非线性分步建模技术对结构施工全过程进行模拟分析;基于模拟结果确定了结构合拢温度和变形预调值,并对结构施工过程和加载过程关键杆件进行监测。结果表明:施工过程中温度作用所引起的结构应力可达60MPa,在分析时应考虑构件安装温度的影响;采用正装迭代法确定结构变形预调值可有效控制结构的最终位形,合理选择合拢温度可降低竣工后结构的应力水平,最大应力降幅达40MPa;施工过程和加载过程中结构关键杆件应力及位移均在可控范围之内,施工方案可行。研究成果可为类似结构施工提供技术支撑。 相似文献
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广州珠江新城西塔施工过程内外筒竖向变形差值研究 总被引:5,自引:5,他引:0
在广州珠江新城西塔施工过程模拟的基础上,对西塔施工过程中的结构变形状况进行综合分析.重点关注内外框筒的竖向变形、竖向变形差以及施工竖向变形预调值这3项内容.分析了内外筒的竖向变形以及竖向变形差随时间和空间的变化规律,并对施工竖向变形预调值随结构高度的变化作了总结,为工程施工预调值的设置提供了依据. 相似文献
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中央电视台(CCTV)新台址主楼由两倾斜塔楼、L形大悬臂以及裙房组成,其特殊的造型设计使得施工过程结构的变形发展异常复杂。由于施工采用两倾斜塔楼独立安装、大悬臂从塔楼逐步悬伸对接的施工方案,导致在施工过程中,上部结构除了在自身荷载作用下产生变形外,还会随着地基不均匀沉降而发生变形。因此必须对结构构件的安装位形设置预调值,以保证施工完成后的结构位形达到设计位形,否则成型位形将不满足设计要求,甚至会导致大悬臂结构无法顺利安装。本文建立了基础与上部结构的一体化有限元模型,考虑了桩、土、筏板与上部主体结构的相互作用,分析评估了地基沉降对结构变形的影响。计算结果表明,考虑地基不均匀沉降,其变形预调值在悬臂端,竖向增大了11.9mm(竖直向上为正),水平向分别增大了-16.6mm(正南方向为正)和10.6mm(正东方向为正)。施工实践证明,按照考虑基础不均匀沉降影响获得的结构变形预调值安装,可以保障大悬臂准确合拢。 相似文献
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Sheng Xiang Bin Cheng Le Zou Soheila Kookalani 《The Structural Design of Tall and Special Buildings》2020,29(5)
Glass fiber‐reinforced polymer (GFRP) elastic gridshell is composed of long continuous GFRP tubes and achieves its shape through the elastic deformations during the lifting construction process. However, the complicated mechanical behaviors during the practical forming process are rarely examined in the previous researches. In this research, an innovative approach consolidating the form‐finding analysis and the construction simulation is proposed for the GFRP elastic gridshells. The integrated approach, which is developed with the ABAQUS and Python, is based on finite element analysis and iterative optimization; therefore, the mechanical deformations of gridshell can be accurately taken into account. The procedure of the integrated analysis is comprehensively presented by taking a typical double‐hump gridshell as an example. The form‐finding results (i.e., the flat lattices) derived from the iteration are found to be insensitive to the initial input. The structural behavior indexes (e.g., deflections, support reactions, and sectional stresses) during the lifting construction process are also available in the analysis. Based on the indexes, some general structural features of such gridshells are concluded. The achievements provide novel perspectives for the form‐finding analysis of GFRP elastic gridshells where lifting construction is involved, which is beneficial for the design and analysis of such structures. 相似文献
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Ning ZHANG Xu LI Qinghui JIANG Xingchao LIN 《Frontiers of Structural and Civil Engineering》2019,13(5):1036
Numerical manifold method (NMM) is an effective method for simulating block system, however, significant errors are found in its simulation of rotation problems. Three kinds of errors, as volume expansion, stress vibration, and attenuation of angular velocity, were observed in the original NMM. The first two kind errors are owing to the small deformation assumption and the last one is due to the numerical damping. A large deformation NMM is proposed based on large deformation theory. In this method, the governing equation is derived using Green strain, the large deformation iteration and the open-close iteration are combined, and an updating strategy is proposed. The proposed method is used to analyze block rotation, beam bending, and rock falling problems and the results prove that all three kinds of errors are eliminated in this method. 相似文献
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结合南京南站电缆隧道工程沉井施工过程中遇到的难点,首先介绍了采取的施工方案,然后利用有限元方法分析了沉井施工对邻近高铁桥基的影响,为安全施工提供理论依据。在此基础上,进一步分析了沉井的长宽比、面积比及下沉深度对周边土体和邻近高铁桥基的影响规律。桥基的监测数据表明,沉井施工未对桥基造成影响,同时也证明了有限元分析结果的正确性。根据有限元分析结果和现场监测数据,泥质砂岩地质条件下,沉井下沉对周边土体竖向位移的影响范围为1倍下沉深度。另外,若沉井底标高低于高铁桥基桩底标高,沉井下沉势必影响桥基稳定,必须采取相应加固措施确保桥基的安全。 相似文献
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上海中心大厦在长期荷载作用下结构竖向构件间的差异变形会在水平构件中产生较大的次内力。利用MIDAS软件的施工过程模拟功能,得到竖向构件在不同施工阶段的内力情况。通过混凝土B3模型,根据内力计算得到竖向变形。并将竖向变形施加到ETABS整体模型中的相应构件中,考察由于竖向构件之间的差异变形在相应的水平构件中产生次内力情况。在分析的过程中,比较了不同的水平构件连接方案对结构次内力的影响。分析结果表明:随着时间的推移,构件的竖向变形逐渐扩大,竖向差异变形在水平构件产生较大的次内力,工程设计中应该考虑此因素对结构的影响。图11表5参9 相似文献
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Numerical analysis and full‐scale experiment on K‐joint deformations in the crank arms of lattice transmission towers 下载免费PDF全文
After completion of the construction process including wire stringing of 1,000 kV ultrahigh voltage (UHV) cat‐head electric transmission towers, the outward horizontal K‐joint deformation of one side crank arm may usually exceed 70 mm. Joint slip effects were ignored in the initial structural design of transmission towers, which induced that the calculated K‐joint displacements are much lower and the real deformation cannot meet with the requirement of the acceptant code. First, the shortcomings of the traditional unit load method used to calculate the displacements of transmission towers connected by bolt joints were analyzed. Second, a coefficient for describing the axial force state of bolted joints was proposed. The connection numbers for different types of members in the crank arms of a UHV cat‐head transmission tower were determined. The traditional unit load method was enhanced by importing the force state coefficient and specifying the detailed connection numbers. The K‐joint displacements calculated by the enhanced formula were compared with the experimental results by full‐scale tower experiment. It shows that the enhanced unit load method is suitable for calculating K‐joint deformations in the crank arms of UHV cat‐head transmission towers. Lastly, contribution weight coefficients of different members for K‐joint displacements of the UHV cat‐head transmission tower were calculated by the enhanced unit load method. For bolt joints connected with the tower members with high contribution weight coefficients, the manufacturing accuracy of bolt holes should be improved, and the bolt clearance should be decreased, which can significantly reduce the K‐joint deformation of UHV cat‐head transmission towers. 相似文献