【作者】 李斌；

【导师】 房贞政；

【作者基本信息】 福州大学 ， 结构工程， 2003， 硕士

【摘要】 随着社会经济的发展，高层、大跨建筑不断涌现，其结构形式也趋于多样化。无粘结预应力混凝土扁梁楼盖在高层、大跨建筑中广泛应用。作为一种新型结构体系，扁梁的梁宽不仅大于梁高，且常大于柱宽，其框架节点的传力机理甚为复杂。目前，国内外对无粘结预应力混凝土扁梁框架节点的受力性能、设计方法和构造措施尚缺乏较系统的研究，我国现行设计规范也还未对无粘结预应力混凝土扁梁框架结构做出明确的规定。为了进一步推广无粘结预应力混凝土扁梁框架结构体系，尤其是在地震设防区的进一步推广应用，有必要研究其框架节点的抗震性能。 本文试图在理论研究和试验分析的基础上，分析探讨中间层无粘结预应力混凝土扁梁框架节点的抗震性能。采用变角空间桁架模型对节点外核芯区受力机理进行分析，并根据构件的“压弯剪扭”相关关系推导出一种新的能反映扁梁框架节点外核芯区受力状况的抗剪承载力计算公式。通过拟静力试验，研究在相同预应力度条件下预应力筋分别穿过框架节点内核芯区和外核芯区对节点抗震性能的影响。研究扁梁框架节点的抗剪承载力、变形、耗能、延性和刚度退化等抗震性能。 从试验破坏现象及相关数据分析，得到以下主要结论： 1．╂型扁梁框架节点的破坏形态为外核芯区剪切破坏，而┣型扁梁框架节点的破坏形态为扁梁梁端弯剪破坏。 2．拟静力试验过程中，无粘结预应力混凝土扁梁框架节点试件在屈服之前，无粘结预应力筋的预应力值仅有微小波动，总的趋势是基本保持不变。当试件屈服以后，预应力筋开始承担部分拉力，但在试件破坏之前，无粘结预应力筋均未屈服。 3．中间层扁梁框架节点在低周反复荷载作用下，位移延性系数均达到4以上，具有较好的延性，满足延性抗震设计要求。更多还原

【Abstract】 AbstractWith the development of economy and society, high buildings and wide-span structures, which structural types are tending to be diversified, come forth continuously. Unbonded prestressed concrete flat beam floor is widely applied in the structures above mentioned. As a new structural system, the width of flat beam section is not only larger than its height, but also larger than the width of column section, which makes the mechanism of loads transfer in the joints more complex. Less systematic researches in the behaviour of loads transfer, design methods and construction measure are processed at home and abroad. And there aren’t specific regulations for unbonded prestressed concrete flat beam frame joints in the Chinese aseismatic design specifications. In order to make the structural system more popularized, especially in the zone of seismic defense, it’s necessary to research the aseismatic behaviour of these joints.Based on the theory and test, the aseismatic behaviour of the joints in the middle level of unbonded prestressed concrete flat beam frame is analyzed and discussed in this paper. Varied-angle truss model is applied to analyze the loading behaviour of the exterior core of unbonded prestressed concrete flat beam frame joints under the torsion plus shear, bend and compression. And a new formula is derivated to reflect the inflection of additional torsion to the exterior core of the joints. The aseismatic behaviour of the joints is surveyed by means of pseudo-static test, which takes into account the different affection of the unbonded prestressed tendons respectively passing through the interior core and the exterior core with the same PPR. And the aseismatic capacity of shear resistant strength, deform, energy dissipation, ductility and rigidity degeneration is also researched.The major conclusions from the model of failure and data analysis are shown in the following item:1.The failure model of + is shear failure in the exterior core, while that of is bend and shear failure in the ends of flat beam.2.In the process of pseudo-static test, the stress of unbonded prestressed tendons is invariable approximately before the yielding of the specimens. The tendons don’t begin to take action until the specimens yield, but don’t yield themselves in the whole process.3.The displacemental ductility coefficients of the joints in the middle level of unbonded prestressed concrete flat beam frame surpass 4, which means this type of structure has better ductility and can meet the demands of ductility aseismatic design.更多还原