High-rise buildings-- frame-wall structure Abstract
This paper describes a framework widely used in office buildings, school buildings, hospitals and hotels and other high-rise buildinghear wall structure, also known as frame structure, is a structural system consisting of frame and shear wall frame structure has the flexibility and freedom to use space to meet the requirements of different architectural features, but in general the level of force to shear deformation-based, inter-layer displacement larger shear wall structure on the contrary, there is a greater lateral stiffne, but the layout is not flexible enough, and earthquakes larger force.Frame structure is affected by a new force in the form of two different structures of the lateral force, which combines both a little from each other, in the structural design of tall buildings in the plane to provide a larger space for construction use.So whether it is earthquake or non-earthquake zone, frame structure have been widely used.Specifically, the framework frame structure is different from pure frame structure frame, shear wall structure is also different from the structure of the shear wall shear.Because, in the lower floor, shear displacement is small, it took the frame by bending curve deformation, shear force to bear most of the levels, the upper floor is the opposite, increasing shear displacement, there is the outside trend, but there is a tendency within the framework of the received frame to pull shear deformation by shear curve, when the two work together through the floor, between the upper and lower layers of distortion tends to be uniform, with layers of beams and cro-sectional dimensions tendons also tends to be uniform, compared to the frame structure, structural stiffne and bearing capacity has been greatly improved.1.Structure and properties of a shear wall From the shape of the point of view, the vertical shear can be seen as one side of the floor to place , from the point of view of resistance to vertical force , it can be seen as elongated frame column , from the perspective of resistance to lateral forces , it can be seen as a vertical cantilever .Similar to the floor , due to the larger surface area , temperature shear prone to shrinkage cracks , and therefore typically configured with double bi-directional shear distribution tendons.And similar frame column , in order to ensure a certain ductility compreion member in the vertical force , shear walls also control the axial compreion ratio .Compared with the frame columns , shear walls when preure has the following differences: a greater role in the first , shear walls need to play , so the more stringent requirements of axial compreion ratio than the frame column .Second , shear generally thin , easy buckling under preure .In addition , vertical shear force is being transmitted floor , these forces may have some eccentricity of shear to produce plane bending , so the vertical distribution of shear reinforcement in addition to outside temperature stre resistance , also has the role of plane bending resistance .Similar to the cantilever , shear walls to resist lateral shear and bending forces ( horizontal load ) to produce , so the level of distribution of shear reinforcement in addition to temperature stre resistance , but also need to resist shear .In order to resist the in-plane bending moments , shear wall ends of longitudinal reinforcement should be a part of centralized configuration , in addition to the vertical wall reinforcement can resist the distribution part of the plane moments .2 .frame structure optimized layout and construction requirements shear walls Shear number of settings related to the economic frame structure system, reasonable.In accordance with regulatory requirements , in order to give full play to the framethe sum EcIw control , horizontal displacement structure of shear wall structure , the lateral stiffne of the structure is mainly composed of the same shear direction of each piece sectional bending stiffne decreases with EcIw increases.Generally horizontal displacement limits to meet the number of shear wall structure as a basis for setting more appropriate .Specification frameshear wall structure, the lateral force resisting shear wall is the main structural component , in order to make the frameshear wall structure optimization design is particularly important for the construction cost savings guiding significance.References [1] Fuxue Yi.practical structural design of tall buildings [M] 2nd edition, Beijing: China Building Industry Pre, 2010 [2 ] Guoren Jun.rise- building frame: shear wall structure design [M] Beijing: China Building Industry Pre, 2004 摘 要：
本文介绍了广泛应用于办公楼、教学楼、医院和宾馆等高层建筑的框架—剪力墙结构，了解框架和剪力墙的受力特点，在设计中结合建筑使用确定剪力墙的布置，以及如何进行优化设计，达到节约能源、降低造价的目的。 关键词：框剪结构 高层建筑 抗侧刚度 优化设计
框架-剪力墙结构也称框剪结构，是由框架和剪力墙组成的一种结构体系，框架结构拥有灵活自由的使用空间，满足不同建筑功能的要求，但在水平力作用下一般以剪切变形为主，层间位移较大，剪力墙结构却相反，有较大的抗侧刚度，但平面布局不够灵活，且地震力较大。框剪结构是由两种不同的抗侧力结构组成的新的受力形式，它综合了二者的有点，取长补短，在高层建筑的结构设计中能为建筑使用提供较大的平面空间。所以无论是震区还是非震区，框剪结构都得到广泛的应用。
具体来讲，框剪结构的框架不同于纯框架结构中的框架，剪力墙在框剪结构中也不同于剪力墙结构中的剪力墙。因为，在下部楼层，剪力墙的位移较小，它拉着框架按弯曲型曲线变形，剪力墙承受大部分水平力，上部楼层则相反，剪力墙位移越来越大，有外侧的趋势，而框架则有内收的趋势，框架拉剪力墙按剪切型曲线变形，当两者通过楼板协同工作时，上下各层层间变形趋于均匀，各层梁柱截面尺寸和配筋也趋于均匀，相比框架结构，结构刚度和承载力都有了很大提高。
1 剪力墙的结构性能
从形状上看，剪力墙可看作一面竖向放置的楼板，从抵抗竖向力的角度来说，它可以看作拉长了的框架柱，从抵抗侧向力的角度来说，它可以看作一根竖向悬臂梁。与楼板相似，由于表面积较大，剪力墙容易出现温度收缩裂缝，因此剪力墙通常配置有双层双向的分布筋。与框架柱类似，为保证受压构件在竖向力作用下具有一定的延性，剪力墙也要控制轴压比。与框架柱相比，剪力墙受压时具有以下不同点：第一，剪力墙需要发挥的作用更大，因此轴压比要求比框架柱更严。第二，剪力墙一般较薄，在压力作用下容易失稳。此外，剪力墙受到的竖向力是楼板传递的，这些作用力可能具有一定的偏心，对剪力墙产生平面外弯矩，因此剪力墙的竖向分布筋除了抵抗温度应力之外，还具有抵抗平面外弯矩的作用。与悬臂梁类似，剪力墙要抵抗侧向力（水平荷载）产生的剪力和弯矩，因此剪力墙的水平分布筋除了抵抗温度应力之外，还需要抵抗剪力。为了抵抗平面内弯矩，剪力墙的端部应集中配置一部分纵筋，除此之外，墙身竖向分布筋也能抵抗一部分平面内弯矩。
2 框剪结构中剪力墙的优化布置及构造要求
剪力墙的数量设置关系到框剪结构体系的经济、合理。按照规范要求，为能充分发挥框架-剪力墙体系的结构特性，剪力墙在结构底部所承担的地震弯矩值应不少于总地震弯矩值的50%，否则应按框架体系对待。在框架-剪力墙结构中，结构的侧向刚度主要由同方向各片剪力墙截面弯曲刚度的总和EcIw控制，结构的水平位移随EcIw 增大而减小。一般以满足结构的水平位移限值作为设置剪力墙数量的依据较为合适。规范规定框架-剪力墙结构弹性层间位移角不大于1/800。同时,剪力墙数量也不宜过多，否则地震作用相应增加，会使绝大部分水平地震力被剪力墙吸收，框架的作用不能充分发挥，而且会增加造价，既不合理也不经济。
剪力墙的位置设置与结构的平面布置有关，一般应双向布置。在框架-剪力墙结构中，剪力墙是结构的主要抗侧力构件，为了使框架-剪力墙结构在两个主轴方向均具有必需的水平承载力和侧向刚度，应在两个主轴方向均匀布置剪力墙，形成双向抗侧力体系。如果仅在一个主轴方向布置剪力墙，将造成两个主轴方向结构的水平承载力和侧向刚度相差悬殊，可能使结构整体扭转，对结构抗震不利。每个方向上的剪力墙应尽量做到“分散、均匀、周边、对称”。
剪力墙的布置应考虑地震力分散作用于刚度大致相等的多片剪力墙上。若集中布置，地震力便集中作用，造成墙体设计困难甚至破坏，其他剪力墙和框架因较弱难以承受这部分地震力，以致结构安全无法保障。
同方向的各片剪力墙应比较均匀地布置在建筑平面各个区段。剪力墙布置不宜过分集中，单片剪力墙底部承担的水平剪力不宜超过结构底部总剪力的40%，以免地震力在各框架间的不均匀分配。 3 框剪结构的优化设计
目前，随着高层建筑的迅猛增加，建筑成本的不断上升，不少房地产开发商要求设计单位为其节省工程投资，甚至对工程的钢筋用量相当严格，并且“高规”对高层建筑的结构选型尤其是合理布置并没做出具体明确的规定，作为一名结构设计工作者，如何在激烈的市场竞争中立足，如何执行好国家各项设计规范，如何在保证结构安全的前提下使得结构设计经济合理，是当前我们最需要思考的问题，这就需要我们清楚地理解规范，灵活地运用规范。
框架一剪力墙结构的优化设计是对剪力墙和框架分别进行优化，它包括初始合理选型、优化布置和计算后的优化设计。初始合理选型、优化布置在上一节中已详细介绍，计算后的优化设计分为框架和剪力墙两个部分，根据其中框架结构构件内力的计算分别对框架梁、柱及楼板结构进行优化设计，可以优化梁、板、柱的几何尺寸，当框剪结构中剪力墙的水平侧移值达到或者接近等于规范规定的最大侧移值时，剪力墙的厚度最优，最后组成新的框剪结构体系进行结构内力分析，按照计算所得结果，重新对框架结构构件、剪力墙的位置进行优化设计。 4 结语
框剪结构以其良好的受力性和适用性在高层建筑中得到广泛的应用，拥有众多的优势，它兼具框架结构和剪力墙结构的优点，随着高层建筑的迅猛增加，传统设计方法过于保守的局限，对框架-剪力墙结构的优化设计就显得尤为重要，对于节约建设成本具有指导性意义。 参考文献
［1傅学怡实用高层建筑结构设计［M］第２版北京: 中国建筑工业出版社，2010［2郭任俊高层建筑框架: 剪力墙结构设计［M］北京: 中国建筑工业出版社，2004
