第2章+薄壳结构

1、Thin-shell structure,Chapter 2 第二章,Thin-shell structure 薄壳结构,Thin-shell Structure,2.1 Summary 概述 2.2 Relationship between forms and hook faces of the thin-shell structure 薄壳结构形式与曲面的关系 2.3 Classification and mechanical properties of the thin-shell structure 薄壳结构分类和力学性能 2.4 Construction of thin-shell

2、structure 薄壳结构的施工 2.5 Engineering Projects 工程实例,2.1 Summary 概述,Thin-shell structure,Thin-shell structure is a type of shell structure, the thickness of which is much smaller than the size in other directions. The largest difference between thin-shell structure and plate structure is that under the u

3、nstressed state, shell structure has curvature while plate structure is plane. （薄壳结构是一种厚度相比其他方向尺寸小得多的壳体结构。薄壳结构和平板结构最大的区别是，在无应力状态下，壳体结构具有曲率，而平板结构是平面的。）,2.1.1 Conception 概念,Thin-shell structure,Assuming that t is the thickness of the shell and R is the radius of curvature of the middle hook face, when

4、 t / R 1/20 it is called thin-shell structure. （设壳体厚度为t，中曲面曲率半径为R。当壳的t/R1/20时，常称为薄壳。）,Thin-shell structure,1. External loads and dead-weight are primarily balanced by membrane stress in the thin-shell structure. （薄壳结构主要依靠薄膜内力来平衡自重及外荷载）,2.1.2 Characteristics of thin-shell structure 薄壳结构特点,2. The inte

5、rnal forces of the thin-shell structure are spatially distributed.(（薄壳结构的内力流向呈立体分布）, Advantages of the thin-shell structure 薄壳结构的优点 1、Can be applied in Long-span structures; 可形成大跨度空间结构； 2、Light weight and material saving； 自重轻、节约材料； 3、Large stiffness; good integrity; favorable seismic and dynamic pro

6、perties. 刚度大、整体性好，有良好的抗震和动力性能； 4、Various architectural types and attractive appearances 造型多样、美观。,Thin-shell structure, Disadvantages of the thin-shell structure 薄壳结构的缺点 1、A large number of formworks are needed in the construction of cast-in-situ concrete thin shell. 现浇混凝土薄壳需耗费大量模板； 2、Great difficult

7、y in construction. 施工难度大； 3、Poor thermal insulation and acoustic effects. 隔热和声学效果差。,Thin-shell structure,Thin-shell structure,2.1.3 State-of-the-art 发展现状,The Pantheon Dome 古罗马万神殿穹顶,Thin-shell structure,Pier Luigi Nervi,Pier Luigi Nervi (June 21st, 1891 January 9th, 1979) was an Italian engineer and

8、he graduated from the University of Bologna in 1913. Dr. Nervi used to be a professor in the University of Rome from 1946-1961. As a structural engineer as well as an architect, he was famous for inventing the reinforced concrete structure. Pier Luigi Nervi （1891年6月21日 - 1979年1月9日）是意大利工程师。1913年从就读的博

9、洛尼亚大学毕业。Nervi博士在1946年至1961年任教罗马大学。他是一个因为发明钢筋混凝土结构而知名的结构工程师和建筑师。,Thin-shell structure,French National Industrial and Technical Center 法国国家工业与技术中心,Thin-shell structure,Montreal Olympic Stadium 蒙特利尔奥运会体育场,Thin-shell structure,The little auditorium in MIT 美国麻省理工学院小礼堂,Tongji University Auditorium 同济大学大礼堂

10、,钢筋混凝土薄壳结构在我国各地陆续建造，但并没有得到大面积的推广，究其原因，主要是在构造、施工方面研究不够，而且现浇钢筋混凝土薄壳需要耗费大量的木材，不适合我国国情。我国今后应走装配式薄壳结构的道路,Some reinforced concrete thin-shell strutures were established in China in the past several years but not widely promoted. The reasons are as follows: firstly, limited researches have been done on the

11、 constructions of thin-shell structures; secondly, a large number of formworks are needed in the construction of cast-in-situ concrete thin shell which is not suitable for our national conditions. Fabricated thin-shell structures will be promoted in the future in China,Thin-shell structure,2.2.1 Sur

12、face of revolution 旋转曲面,2.2 Relationship between forms and hook faces of thin-shell structures 薄壳结构形式与曲面的关系,Spherical surface 球形曲面,Paraboloid 抛物面,Hyperboloid 双曲面,A surface of revolution is a surface formed by rotating a curve (the generatrix) around an axis. 旋转曲面是由一平面曲线作母线绕其平面内的轴旋转而成的曲面，称为旋转曲面。,Thin

13、-shell structure,2.2.2 Translation surface 平移曲面,Elliptic paraboloid 椭圆抛物面,Hyperbolic paraboloid 双曲抛物面,A Translation surface is a surface formed by moving a vertical curved generatrix along another vertical curved guide line . 一竖向曲母线沿另一竖向曲导线平移而成的曲面称为平移曲面。,Thin-shell structure,2.2.3 Ruled surface 直纹曲面

14、,The ruled surface is a surface formed by moving both ends of a straight line along two fixed curves 一根直线的两端沿二固定曲线移动而成的曲面称为直纹曲面。,Hyperbolic paraboloid 双曲抛物面,1、Saddle shell 在外墙上开侧窗 Making the glasses embedded in the concrete thin shell; 在薄壳混凝土中镶嵌玻璃 Setting the longitudinal windows at the top of the s

15、hell; 在壳顶开纵向天窗 Laying the zigzag roof; 布置锯齿形屋盖,2.3.3 Double-curved shallow shell 双曲扁壳 Little space 受力优于梁式平板结构； 2、Simple construction and unique shape ； 制作简单，造型独特 3、Large stiffness 刚度大、整体性好， 4、Favorable seismic performance； 有良好的抗震性能；, Disadvantages 1、Thin plate 折板很薄，结构本身的隔热效果差。,Thin-shell structure,2

16、. Mechanical properties 折板结构的受力特点,Bidirectional loading 双向受力，双向传力,The function of the crease is to ensure the enough longitudinal stiffness of the structure. 折缝的作用：保证结构的纵向刚度； The role of the diaphragm is to fix the inclined plate to perform its strength. 隔板的作用是固定斜板，以发挥斜板的强 度。,Thin-shell structure,2.

17、 Mechanical properties 折板结构的受力特点,Longitudinal folded plate can be calculated by reference to the theory of simply supported beam. 纵向折板可按照简支梁 的理论进行计算,Thin-shell structure,2. Mechanical properties 折板结构的受力特点,Calculate with 1m wide plate and by reference to the theory of multi-span continuous plate. 取1m

18、宽的板带计算，可按多跨连续板进行内力分析。,2.3.6 New types of metal thin shell 新型金属薄壳,Thin-shell structure,Arched corrugated steel roof 拱形波纹钢屋顶,Thin-shell structure,1. Composition and forms 拱形波纹钢屋顶的组成及结构形式,The arched corrugated steel roof is made of the steel plates with plicated ripples formed by using the specific mac

19、hines to compress color-coated sheets. 拱型波纹钢屋盖是指用专门的成型机组将彩涂板压制成具有褶皱波纹 的钢板组合而成。,Rectangular cross-section,Trapezoidal cross-section,hyperbolic arch shell 双曲拱形薄壳,High flexural rigidity 抗弯刚度大,Complex performance 施加荷载后，性能复杂,2.4.1 Cast-in-place 现浇式施工方法,Thin-shell structure,2.4.2 Prefabricated 装配式施工方法,2.4

20、 Construction of thin-shell structure 薄壳结构的施工,2.4.1 Cast-in-place 现浇式施工方法,Thin-shell structure,Advantage： good integrity 整体式好,Disadvantage： Complicated mold 模板复杂，制作繁琐 Too many temporary supports 大量的临时支撑 High cost This scheme requires that the assembled brackets should have enough installment area. 壳

21、体的预制壳板间留有一定间隙，并在其间配以钢筋 此连接方案要求拼装支架有足够安装面积。 Use the built-in fitting to connect the shell plates and fill in the gaps with mortar only without reinforced bars inside; This scheme needs smaller installment area. 壳板之间用预埋件焊接， 壳板间不配钢筋，仅灌砂浆 此连接方案的拼装支架面积可小些,Thin-shell structure,2.4.2 Prefabricated 装配式施工方法,

22、2、The design of bracket 支架的设计,Guarantee enough supporting areas for the shell plates and determine the gradient and direction of the supporting areas according to the altitude differences among the angular points. 保证各壳板有足够的支承面，并应根据壳板各角点的高差 确定支点面的倾斜度及方向。,Thin-shell structure,3、Installment of shell pl

23、ate 壳板的安装,The assembling procedure of the shell plate is to start from the center to the boundaries to transfer the assembling errors to the boundaries and eliminate the errors by using the cast-in-place edge members. 壳板的拼装顺序应从中央向两边或四周进行，使拼装偏差累积至边缘，通过现浇边缘构件吸收此偏差。,4、 Crack pouring & removal of the br

24、acket 灌缝和支架的拆除,Thin-shell structure,5、Installment of thin-shell structure 薄壳结构安装,Installment method 安装方法,High altitude assembling method 高空拼装法,integral Jacking method 整体顶升法,Question with bracket,integral lifting method 整体顶升法,By using jack,Small pillars section,Thin-shell structure,5、Installment of thin-shell structure 薄壳结构安装,integral lifting method 整