【作者】 孙绪杰；

【导师】 郑文忠；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2009， 博士

【摘要】 作为一种增层形式,套建增层以其增加层数不受限制、对既有建筑物依赖小而在既有房屋增层改造中得到越来越多的应用。巨型框架结构的主框架承担全部竖向荷载及绝大部分的水平荷载,次框架仅将自身的竖向荷载传递给主框架,承担小部分的水平荷载。去掉第一巨型结构层内的次框架,对结构沿竖向的刚度分布影响不大,可以利用这一点来实现对既有房屋的套建增层。用巨型框架套建增层尚有一些问题亟待解决:如何使其满足抗震规范规定的“小震不坏、中震可修、大震不倒”抗震设防要求,尚需对其倒塌机制进行深入的研究;既有建筑屋盖不能承担巨型框架层的施工荷载,使套建增层巨型框架无法实现逐层施工,对无支撑自承重楼盖施工工艺提出了迫切要求;与施工方法相应的构件设计方法及细部构造措施,较大跨度涉及到预应力技术的一些相关的细部构造措施要求。本文主要针对上述问题,展开工作。本文基于平面杆系模型,采用IDARC-2D非线性分析程序,在引入新建巨型混凝土框架结构适用范围和抗震构造手段的基础上,通过对不同巨型结构层数和次框架层数,建造在I、II、III类场地土,设计地震分组为一、二、三组的375榀套建增层巨型框架的抗震性能研究,得出的结论是8度区的套建增层巨型框架的主框架抗震等级按一级,7度区的套建增层巨型框架以50m为界,低于50m时主框架抗震等级按二级,高于50m时按一级设计的框架,满足规范的弹塑性位移角的限值要求,未出现形成机构体系的情况,满足现行抗震规范“大震不倒”的抗震要求。用现行抗震规范推荐的静力弹塑性分析方法,采用倒三角形、均匀两种侧向力分布方式,能力谱法、改进能力谱法和α-T法等三种方法对相同模型进行了的抗震性能分析,得出了与弹塑性动力时程分析相同的结论。套建增层巨型框架是具有转层性质的结构,分析了逐层施工法、主次施工法及巨型结构层自承重施工法对结构构件内力的影响。并提出具体施工过程中应注意的问题。因巨型结构层的荷载巨大,既有建筑物的屋面不能够承担第一巨型结构层施工期间的荷载,论述了无支撑自承重楼盖的施工方法与措施,该方法既不影响既有结构使用,又保证了施工结构的安全。从主次框架的共同工作入手,分析了忽略次框架刚度的简化算法的适用性问题。根据套建增层巨型框架的弹塑性分析得出的设计建议,编制了设计程序,既为套建增层结构方案选取提供了手段,又方便套建增层巨型框架结构的设计。最后,结合哈尔滨市某高校实验楼的套建增层工程,给出了一榀套建增层巨型框架的设计过程与相应的施工方法,并且分析了其在罕遇地震作用下的抗震性能,验证本文弹塑性分析结果,并为具体设计提供参考。更多还原

【Abstract】 As a method to add stories on the building, using the outer-jacketing structure to add stories is more and more widely used in reconstructing the existing buildings, for using this method, the added stories are not restrained, and the existing build-ings are not seriously affected. The main frame of the megaframe structure carries the whole vertical load and the most of horizontal load. The secondary frame only carries it vertical load and transmits it to the main frame, and it carries few horizon-tal load. If the secondary frame in the first storey of the mega structure is removed, the distribution of the structure’s stiffness varies a little. Owing to this characteris-tics, using the outer-jacketing structure to add stories around the existing building can be adopted.There are some problems needed to be urgently solved in using the outer-jacketing megaframe to add stories, such as how to meet the requirement in the seismic code“no damage in the frequent earthquake, mendable in the medium earthquake and no collapse in the strong earthquake”. So it is necessary to make deeper research on the mechanism of collapse. The roof of the existing building can not carry the construction load during the construction of the megaframe floor. Therefore, the added megaframe can not be constructed floor by floor. In this case, the construction technics of no support self bearing floor is urgently needed. The design methods and the detailed construction measures corresponding to the con-struction method and some detailed construction measures relating to the long span prestress technology are needed. In order to solve the above problems, we made some research in this paper.Based on the planar linear element model, using the nonlinear analysis pro-gram IDARC-2D, the seismic performance of 375 outer-jacketing megaframes are investigated. These megaframes are different in stories of megaframe and stories of secondary frame, and they are built in site-class I, II and III and the seismic group of the first, the second and the third. After the using scope of new concrete mega-frame structures and the seismic construction measures are given, the conclusion is: these cases meet the limit of elastic-plastic drift ratio and the transformable system does not occur, which meet the requirement of current seismic code“no collapse in the strong earthquake”. They are: the main frame of outer-jacketing megaframe in the zone of seismic fortification intensity 8 conforming to measure grade 1-st, the height of megaframe under 50m conforming to measure grade 2-nd and that over 50m conforming to measure grade 1-st in zone of seismic fortification intensity 7. The seismic performance of the same model are analyzed by using the static elastic-plastic analysis method recommended in the current seismic code using two kinds of distribution of transverse load, inverse triangle and uniform. Capacity spectrum method, modified capacity spectrum method andα-T method are used to analyze the frames. The same conclusions are got with the elastic-plastic time history me-thod.The outer-jacketing megaframe has the transform floor. The influence of dif-ferent construction methods to the internal force of structural member are analyzed such as floor by floor, main-secondary floor and the self bearing floor of the mega-structure floor. The noteworthy problems during construction are presented. The load of the mega structure floor is too big, and the roof of the existing building can not carry the construction load of the first floor of the mega structure. Considering this, the construction methods and measures of no support self bearing floor is dis-cussed, which can not affect the service of the structure and ensure the safe con-struction.Start with the team work of the main frame and the secondary frame, whether the simplified method of neglecting the stiffness of the secondary frame can be used or not is analyzed. Based on the design proposal got from the elastic-plastic analy-sis of the outer-jacketing megaframe, the design procedure is compiled, which not only provides measures for the scheme selection of this kind of structure, but also facilitates its design.At last, combined with a reconstruction project of a test building in a collage in Harbin, the design progress of an outer-jacketing megaframe and the correspond-ing construction methods were given. The seismic performance of this frame under rarely earthquake was analyzed, and the elastic-plastic analysis results in this paper were verified. All these provided reference for the detailed design of this kind of frame.更多还原