既有建筑轻钢隔震增层的抗震性能研究

发布时间：2018-05-19 12:04

本文选题：钢结构增层 + 层间隔震　；参考：《吉林建筑大学》2015年硕士论文

【摘要】：增层改造是解决城市核心区域房屋土地面积不足的重要手段,其中轻型钢结构增层方法以自重轻、工业化程度高、施工方便迅速、柱网布置灵活、经济效益明显等优势受到广泛应用。但采用轻型钢结构增层,会不可避免的产生上下两部分刚度的差异,同时结构整体的周期、阻尼比等特性会发生较大变化,不利于结构整体的抗震性能。对此,传统的解决办法是对原结构进行抗震加固,这种方法虽提高了构件的承载能力,却没有从根本上解决“上柔下刚”的本质。而层间隔震技术通过布置隔震支座,延长结构自振周期,增大阻尼比,可以“间接”的解决此类问题。本文结合工程实例,运用ANSYS有限元分析软件,依据现行国家规范规程,针对钢结构增层后的整体抗震问题,对四层钢筋混凝土框架结构增加三层钢结构、四种带不同型号隔震支座增加三层钢结构进行静、动力计算分析,总结规律。主要研究内容包括:(1)从结构自身特点考虑,采用瑞雷阻尼理论计算结构阻尼比,并最终确定了本课题研究的混合结构阻尼比取值为0.035,并验证了所得结果的合理性。(2)使用ANSYS软件对原四层钢筋混凝土框架结构增加三层、带隔震增加三层等情况,建立单榀框架模型进行静力分析。研究表明,在地震力作用下直接增层结构的顶部水平位移值要比原结构大许多,且变形主要集中在上部结构;而采用隔震增层方案后,由于隔震层提供了可靠的抗侧刚度,所以上下部结构相对稳定,变形主要集中在隔震层,保证了建筑物的安全。(3)使用ANSYS软件对原四层钢筋混凝土框架结构及直接增加三层、四种不同隔震支座增加三层建立六种三维模型,采用振型分解反应谱法及时程分析法在EI-Centro地震波、Taft地震波及一条人工地震波的作用下进行计算分析。结果表明,在多遇地震多用下,采用隔震增层的结构同比直接增层结构基本周期延长约60%,结构最大层间位移平均降低了约44%,楼层最大剪力降低了45%~55%,最大变形均发生在隔震部分,有力保证了地震作用下建筑物的安全性。(4)通过总结在三条地震波作用下的六种结构的计算结果可以发现,一味的选择大尺寸、大铅芯直径的隔震支座不但会徒增施工难度也会造成经济上的浪费,并且表现力也欠佳。针对本文涉及的实际工程,采用20个GZY500-100型隔震支座作为隔震层布置于新老结构交界处,上部增加三层钢结构,是最为科学经济的增层方案。(5)对本课题所研究的隔震增层结构采用寿命经济分析法进行经济性分析,计算结果表明,尽管在初始造价上会产生1.47%(5.18万元)的额外费用,但从全寿命周期来计算,由于隔震层的设置可以极大的降低灾害损失,采用隔震的结构去除维修及初始造价上的差价仍可以节减少46.07万元的费用,所以引入隔震后的体系经济效益还是很明显的。
[Abstract]:Storey increasing is an important method to solve the shortage of land area of housing in urban core area. Among them, the light steel structure has the advantages of light weight, high degree of industrialization, convenient construction, flexible layout of column net, and so on. Economic benefits are obvious and other advantages are widely used. However, the increase of light steel structure will inevitably cause the difference of stiffness between the upper and lower parts. At the same time, the period and damping ratio of the whole structure will change greatly, which is not conducive to the seismic performance of the whole structure. For this reason, the traditional solution is to strengthen the original structure against earthquake. Although this method improves the bearing capacity of the members, it does not fundamentally solve the essence of "up, soft and rigid". The interstory isolation technology can solve this kind of problems indirectly by arranging isolation bearings, prolonging the natural vibration period of the structure and increasing the damping ratio. In this paper, combined with engineering examples, according to the current national code, according to the ANSYS finite element analysis software, the three-story steel structure is added to the four-story reinforced concrete frame structure in view of the whole seismic problem after the steel structure has been added to the floor. Four kinds of three-story steel structures with different types of isolation bearings are calculated and analyzed, and the rules are summarized. The main research contents include: (1) considering the characteristics of the structure, the Rayleigh damping theory is used to calculate the damping ratio of the structure. Finally, the damping ratio of the hybrid structure studied in this paper is determined to be 0.035, and the reasonableness of the obtained results is verified. The ANSYS software is used to add three stories to the original four-story reinforced concrete frame structure and to increase the three layers with earthquake isolation. A single frame model is established for static analysis. The results show that the horizontal displacement at the top of the structure directly increased by seismic force is much larger than that of the original structure, and the deformation is mainly concentrated in the superstructure. Therefore, the upper and lower parts of the structure are relatively stable, and the deformation is mainly concentrated in the isolation layer, which ensures the safety of the building. It uses ANSYS software to directly add three stories to the original four-story reinforced concrete frame structure. Six kinds of three-dimensional models were established by adding three layers of four different isolation supports. The time-history analysis method of mode decomposition response spectrum method was used to calculate and analyze the EI-Centro seismic wave and an artificial seismic wave. The results show that, under the condition of frequent earthquakes, the basic period of the structure with isolation and increasing layer is prolonged by about 60 times compared with that of the direct increase structure, and the maximum floor displacement of the structure is reduced by about 44.4 percent, the maximum shear force of the floor is reduced by 45 / 5555 and the maximum deformation occurs in the isolation part. By summing up the calculation results of six kinds of structures under the action of three seismic waves, it can be found that large size is always chosen. The isolation bearing with large lead diameter will not only increase the difficulty of construction, but also cause economic waste and poor performance. In view of the actual engineering involved in this paper, 20 GZY500-100 isolation supports are used as isolation layers at the junction of new and old structures, and three stories of steel structures are added to the upper part. It is the most scientific and economical adding layer scheme. (5) the economic analysis of the isolated layer structure studied in this paper is carried out by using the life economic analysis method. The calculation results show that, although the additional cost of 1.47 yuan (51800 yuan) will be incurred in the initial cost, But from the whole life cycle calculation, because the isolation layer can greatly reduce the disaster loss, using the isolated structure to remove the maintenance and the difference in the initial cost can still save 460700 yuan of the cost. So the system economic benefit after introducing isolation is very obvious.
【学位授予单位】：吉林建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU392.5;TU352.11

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