带加强层的框架—核心筒结构受力性能研究

发布时间：2018-03-03 18:24

本文选题：框架—核心筒结构　切入点：加强层　出处：《西安工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：在高层和超高层建筑中,框架——核心筒结构在侧向荷载作用下的顶点位移往往会因为结构的抗侧移刚度不足而超过国家规范的限值。为解决这个问题,结构工程师通常在结构中布置加强层以提高结构抗侧刚度。这样就会出现竖向刚度不均导致加强层附近产生内力和变形的突变,使结构难以形成良好的屈服机制。本文在总结国内外对带加强层的框架——核心筒结构研究的基础上,通过有限元分析软件ETABS建立了 40层框架——核心筒模型,主要研究不同数量、不同刚度以及不同类型的加强层对结构在风荷载和地震作用下的受力性能的影响。主要结论有:1)加强层的设置能明显减小结构的侧移,且其数量越多刚度越大对结构侧移的减小越多,但减小幅度则会随之降低。2)加强层的设置会使其附近几层结构构件产生2～8倍的内力突变,且其刚度越大突变越剧烈,导致结构形成不利于抗震的薄弱层。而加强层数量增加时构件内力突变会减小,有利于抗震。3)有限刚度加强层相比刚性加强层能使结构突变程度减轻20%～40%,设置带状桁架则会使框架柱轴力突变程度减小1/3。4)弹性时程法揭示出了结构的局部地震反应特征,其分析结果普遍要小于振型反应谱法,但是仍有个别例外的情况,应选择时程法和反应谱法的最不利的情况进行包络设计。5)Pushover分析中,模型被推覆到目标位移后设置1～2道加强层的结构延性最好,而当不设置或设置三道加强层的结构发生推覆破坏。6)随着加强层数量的增加,性能点处的加速度谱逐渐增加,位移谱逐渐减少;同时结构基底剪力逐渐增加,顶点位移逐渐减少。7)加强层的存在会导致其附近出现柱铰,不满足"强柱弱梁"的要求,加强层伸臂塑性铰均比剪力墙塑性铰开展得要早,符合"强筒体,弱伸臂"的延性要求。
[Abstract]:In high-rise and super-high-rise buildings, the vertex displacement of frame-core tube structure under lateral load often exceeds the limit of the national code because of the insufficient lateral stiffness of the structure. Structural engineers usually place strengthened layers in the structure to improve the lateral stiffness of the structure. Thus, there will be a sudden change in the internal force and deformation near the strengthening layer due to the uneven vertical stiffness. It is difficult for the structure to form a good yield mechanism. On the basis of summing up the research on frame-core tube structure with reinforced layer at home and abroad, a 40-story frame-core tube model is established by the finite element analysis software ETABS. The effects of different numbers, different stiffness and different types of stiffeners on the behavior of structures subjected to wind load and earthquake are studied. The main conclusion is that the setting of strengthening layer can obviously reduce the lateral displacement of the structure. The larger the stiffness is, the smaller the lateral displacement of the structure is, but the smaller the magnitude is, the smaller the reinforcement layer is, and the more the stiffness is, the more abrupt the internal force will be, and the more the stiffness is, the more violent the internal force will be, and the larger the stiffness is, the smaller the magnitude will be, and the larger the stiffness is, the smaller the magnitude will be. As the number of strengthened layers increases, the internal force of the member will decrease. It is advantageous to earthquake resistance. 3) compared with rigid strengthening story, finite stiffness strengthened story can reduce the sudden change degree of structure by 20% and 40%, and the sudden change degree of axial force of frame column will be reduced by 1 / 3. 4) when the truss is installed, the local seismic response characteristics of the structure can be revealed by the method of elasticity. The analytical results are generally smaller than the modal response spectrum method, but there are still some exceptional cases. The most unfavorable cases of the time-history method and the response spectrum method should be selected for enveloping design. 5 pushover analysis. When the model is pushed to the target displacement, the ductility of the structure with 1 or 2 reinforcement layers is the best, but when the structure without or with three strengthened layers occurs nappe failure. 6) with the increase of the number of strengthening layers, the acceleration spectrum at the performance points increases gradually. At the same time, the shear force of the base of the structure gradually increases, and the displacement of the vertex decreases gradually. 7) the existence of the strengthened layer will lead to the appearance of column hinge nearby, which does not meet the requirements of "strong column and weak beam". The plastic hinge of the strengthened layer extension arm is earlier than the shear wall plastic hinge, which meets the ductility requirement of "strong tube body, weak extension arm".
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU973.17

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