第2章+薄壳结构

1、Tianjin UniversityThin-shell structureChapter 2 第二章Thin-shell structure薄壳结构Tianjin UniversityThin-shell Structure2.1 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

2、 Construction of thin-shell structure 薄壳结构的施工2.5 Engineering Projects 工程实例Tianjin University2.1 Summary 概述Thin-shell structureThin-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 structu

3、re and plate structure is that under the unstressed 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Tianjin UniversityThin-shell structureAssuming that t is the thickness of the shell and R

4、 is the radius of curvature of the middle hook face, when 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。）Spherical shell 球壳cylindrical lattice shell 柱面网壳Hyperboloid shell 双曲面壳Some projects of thin-shell structuresTianjin UniversityThin-shell structure1. External l

5、oads 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External loads and dead-weightMembrane stressExternal loadsSupporting structurestransmitted directly2. The internal forces of the thi

6、n-shell structure are spatially distributed.(（薄壳结构的内力流向呈立体分布）Tianjin University 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 properties.

7、 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 structureTianjin University 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 diff

8、iculty in construction. 施工难度大；3、Poor thermal insulation and acoustic effects. 隔热和声学效果差。Thin-shell structureTianjin UniversityThin-shell structure2.1.3 State-of-the-art 发展现状The Pantheon Dome古罗马万神殿穹顶Tianjin UniversityThin-shell structurePier Luigi NerviPier Luigi Nervi (June 21st, 1891 January 9th, 19

9、79) was an Italian engineer and 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

10、 - 1979年1月9日）是意大利工程师。1913年从就读的博洛尼亚大学毕业。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。Tianjin UniversityThin-shell structureFrench National Industrial and Technical Center法国国家工业与技术中心Tianjin UniversityThin-shell structureMontreal Olympic Stadium蒙特利尔奥运会体育场Tianjin UniversityThin-shell structure

11、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 r

12、easons are as follows: firstly, limited researches have been done on the 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 structure

13、s will be promoted in the future in ChinaTianjin UniversityThin-shell structure2.2.1 Surface 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

14、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。Tianjin UniversityThin-shell structure2.2.2 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 curv

15、ed 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。Tianjin UniversityThin-shell structure2.2.3 Ruled surface 直纹曲面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 & torsional shell 鞍面壳、扭

16、面壳Tianjin UniversityThin-shell structureCylindrical shell 柱面壳2、Cylindrical shell 柱面壳Tianjin UniversityThin-shell structureConical shell 锥面壳3、Conical shell 锥面壳Tianjin University2.3 Classification and mechanical properties 薄壳结构分类和力学性能2.3.1 Thin Spherical Shell 球面薄壳Thin-shell structureTianjin Universit

17、yThin-shell structure1. Composition and forms 穹顶薄壳的组成及结构形式 A dome shell is composed of the shell plate, the bearing ring and the support structure.穹顶薄壳由壳板、支座环、下部支承结构三部分组成。Ribbed dome肋形穹顶 Smooth dome平滑穹顶Multi-surface dome多面穹顶（1）Shell plate 壳板Tianjin UniversityThin-shell structure1. Composition and fo

18、rms 穹顶薄壳的组成及结构形式 A dome shell is composed of the shell plate, the bearing ring and the support structure.穹顶薄壳由壳板、支座环、下部支承结构三部分组成。（2） Bearing ring 支座环 The base of dome bearing Closed loop Huge thrust Great size0.5m2mTianjin UniversityThin-shell structure1. Composition and forms 穹顶薄壳的组成及结构形式 A dome sh

19、ell is composed of the shell plate, the bearing ring and the support structure.穹顶薄壳由壳板、支座环、下部支承结构三部分组成。（3） Support structure 支撑结构supported on the vertical load-carrying member. 支撑在结构竖向承重构件上。supported on the beams or columns. 支撑在梁、柱上。supported on the inclined beams or columns. 支撑在斜梁、斜柱上。supported on

20、the ground and transfer the forces to the foundation. 支撑在地面上，将力直接传递给基础。Tianjin UniversityThin-shell structure2. Mechanical properties 穹顶薄壳的受力特点In general, the radial and circumferential bending moment of the shell plate can be ignored. 一般情况下壳板的径向和环向弯矩可以忽略。Under the function of axial symmetrical load

21、s, the radial direction of the shell plate bears compression while the circumferential direction of the shell plate bears compression or tension.轴向对称荷载作用下，圆顶径向受压；环向可能受拉或受压。Tianjin UniversityThin-shell structure2. Mechanical properties 穹顶薄壳的受力特点The bearing ringThe bearing ring undertakes the thrust t

22、ransferred from the shell plate. It bears tension in the horizontal direction while moment as well as shear in the vertical direction. 承受壳板传来的推力；水平方向受拉，竖直方向承受弯矩、剪力。Tianjin University2.3.2 Cylindrical thin shell 圆柱形薄壳Thin-shell structure1. Composition and forms 圆柱形薄壳的组成及结构形式 A cylindrical thin shell

23、is composed of the shell plate, the spandrel beam and the diaphragm.圆柱形薄壳由壳板、边梁、横隔板三部分组成。Tianjin UniversityThin-shell structure2. Mechanical properties 圆柱形薄壳的受力特点The differences between Cylindrical thin shell and Barrel-vaultDifferencesCylindrical thin shell Barrel-vaultDiaphragm Lateral forceLongit

24、udinal force Spatial structure Tianjin UniversityThin-shell structure2. Mechanical properties 圆柱形薄壳的受力特点Span-wavelength ratio（跨波比） l1/ l23 similar to a beam & calculated by reference to the theory of beams.梁理论Span-wavelength ratio（跨波比） l1/ l21/2 similar to an arch & calculated by reference t

25、o the membrane theory.薄膜理论Span-wavelength ratio（跨波比） l2l1 / l2 3 Calculated by reference to the bending moment theory or semi-bending moment theory.弯矩理论/半弯矩理论Tianjin UniversityThin-shell structure3. Processes of the treatment of the hole 圆柱形薄壳的洞口处理过程Setting windows on the outer wall; 在外墙上开侧窗 Making

26、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 shell; 在壳顶开纵向天窗Laying the zigzag roof; 布置锯齿形屋盖Tianjin University2.3.3 Double-curved shallow shell 双曲扁壳Little space & Small roof & Cost savings.结构空间小；屋面面积小；节省造价。Thin-shell structure1

27、. Composition and forms 双曲扁壳的结构组成与形式A double-curved shallow shell is composed of the shell plate and the edge members.双曲扁壳由壳板和周围边缘构件组成。The largest span of the double-curved shallow shell can reach 100m .双曲扁壳的跨度最大可至l00m。Tianjin UniversityThin-shell structure2. Mechanical properties 双曲扁壳的受力特点Under the

28、 function of the full-span uniform vertical loads, the shell plate mainly undertakes the membrane forces while it also bears some transverse moments at its edge. 在满跨均布竖向荷载作用下，壳板的受力以薄膜内力为主，在壳体边缘受一定的横向弯矩。central area bi-axial pressureEdge region positive momentFour corners region shearTianjin Universi

29、ty2.3.4 Saddle shell & torsional shell 鞍面壳和扭面壳Thin-shell structure1. Composition & forms 鞍面壳和扭面壳的组成及结构形式Saddle shell torsional shell Ruled surface & Hyperbolic paraboloidSimple Reinforcement & simple moldVarious typesShort production cycle & Low costCanteenAuditoriumWarehouseThe

30、mallThe railway stationTianjin UniversityThin-shell structure2. Mechanical properties 鞍壳、扭壳的受力特点The load-carrying theory of saddle shell and torsional shell is reasonable and it is calculated by reference to the nonmomental theory. 鞍壳、扭壳受力合理，一般均按无弯矩理论计算。principal tensile stress principal compressive

31、 stressTianjin University2.3.5 Folded plate structure 折板结构Thin-shell structure1. Composition and forms 折板结构的组成及结构形式Long and narrow platesSpan 30mDiaphragm.Spandrel beam load-bearinglateral bracingbiaxial stress guaranteeElongated roofTianjin UniversityThin-shell structure1. Composition and forms 折板结

32、构的组成及结构形式Overhanging cantilever外伸悬挑Main formsTianjin UniversityThin-shell structure1. Composition and forms 折板结构的组成及结构形式Deformed Folded plate 变形折板Main formsTianjin UniversityThin-shell structure1. Composition and forms 折板结构的组成及结构形式Parallel combination并列组合Main formsTianjin UniversityThin-shell struct

33、ure1. Composition and forms 折板结构的组成及结构形式Reverse parallel combination反向并列组合Main formsTianjin UniversityThin-shell structure1. Composition & forms 折板结构的组成及结构形式 Advantages 1、Better loading features than beam plate structure; 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 stiff

34、ness & Good integrity; 刚度大、整体性好，4、Favorable seismic performance； 有良好的抗震性能； Disadvantages 1、Thin plate & Bad thermal insulation effect; 折板很薄，结构本身的隔热效果差。Tianjin UniversityThin-shell structure2. Mechanical properties 折板结构的受力特点Bidirectional loading & bidirectional force transmission; 双向受力，双向

35、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。Tianjin UniversityThin-shell structure2. Mechanical properties 折板结构的受力特点Longitudinal fold

36、ed 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Tianjin UniversityThin-shell structure2. 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宽的板带计算，可按多跨连续板进行内力分析。Tianjin Univers

37、ity2.3.6 New types of metal thin shell 新型金属薄壳Thin-shell structureArched corrugated steel roof拱形波纹钢屋顶 Tianjin UniversityThin-shell structure1. 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 machines

38、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-sectionTrapezoidal cross-sectionhyperbolic 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Tianjin University2.4.1 Cast-in-place 现浇式施工方法Thin-shell structure2.4.2 Prefabricated装配式施工方法2.4

39、Construction of thin-shell structure 薄壳结构的施工Tianjin University2.4.1 Cast-in-place 现浇式施工方法Thin-shell structureAdvantage：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 & Long construction period 成本高，工期长Construction quality is difficult to be

40、guaranteed 施工质量无法保证1、mobile mold 移动式模板Seattle King County Stadium西雅图金郡体育馆Tianjin University2.4.1 Cast-in-place 现浇式施工方法Thin-shell structureAdvantage：Good integrity 整体式好2、 Permanent mold 永久式模板Palazzetto Dello Sport of Rome罗马小体育宫Disadvantage：Complicated mold 模板复杂，制作繁琐Too many temporary supports 大量的临时支撑

41、High cost & Long construction period 成本高，工期长Construction quality is difficult to be guaranteed 施工质量无法保证Tianjin University2.4.1 Cast-in-place 现浇式施工方法Thin-shell structureAdvantage：Good integrity 整体式好3、 Soil tire mold 土胎模Use soil to make the mold 利用泥土做模板4、 Inflatable membrane mold 充气薄膜模板Use inflata

42、ble membrane to make the mold 利用充气薄膜做模板Disadvantage：Complicated mold 模板复杂，制作繁琐Too many temporary supports 大量的临时支撑High cost & Long construction period 成本高，工期长Construction quality is difficult to be guaranteed 施工质量无法保证Tianjin University2.4.1 Cast-in-place 现浇式施工方法Thin-shell structureAdvantage：Good

43、integrity 整体式好5、 Comshell system Comshell 体系Disadvantage：Complicated mold 模板复杂，制作繁琐Too many temporary supports 大量的临时支撑High cost & Long construction period 成本高，工期长Construction quality is difficult to be guaranteed 施工质量无法保证Tianjin UniversityThin-shell structure2.4.2 Prefabricated 装配式施工方法1、Assemble

44、 method 壳板拼装方法Leave some gaps between the prefabricated shell plates and fill in them with reinforced bars; This scheme requires that the assembled brackets should have enough installment area. 壳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 i

45、n 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Tianjin UniversityThin-shell structure2.4.2 Prefabricated 装配式施工方法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。Tianjin UniversityThin-shell structure3、Installment of shell plate 壳板的安装The