建筑大学毕业设计外文文献及译文超高层建筑幕墙系统的结构与性能

中文4553字

毕业设计

外文文献及译文

文献、资料题目：Construction and Performance of

Curtain Wall Systems for Super Highrise Buildings 文献、资料来源：网络

文献、资料发表（出版）日期：2007.4.5

院（部）：机电工程学院

专业：机械制造与自动化

班级：机械1121

姓名：

学号：

指导教师：

翻译日期：2014 年4 月20 日

外文文献：

Construction and Performance of Curtain Wall

Systems for Super Highrise Buildings

Raymond WM Wong

INTRODUCTION

The construction of super highrise buildings has been very active in Hong Kong for decades. Recent renowned projects like the 50-storey Manulife Tower, the 62-storey Cheung Kong Center, the 80-storey “Center”,the 88-storey International Financial Center, and a number of recent residential buildings exceeding 60-storey tall, are without exception, using curtain wall as their external envelope.

Using thin wall as external envelope for tall buildings has always been a challenge to designers and builders, in particular in terms of cost, energy, water-tightness, installation, dimensional and structural stability, interfacing arrangement with other building components and maintenance etc. Making use of the Hong Kong’s experience, the writer wish to highlight some local practices and summarize how such thin wall systems are designed and installed.

USING CURTAIN WALL IN BUILDIGNS OF HONG KONG

High-rise buildings started to spring up in the skyline of Hong Kong since the 1970’s in parallel with her economic take-off from a traditional manufacturing-based industrial economy and transforming herself into an world-renowned international financial centre. High-rise buildings by that time were concentrated in the commercial districts like Central in the Hong Kong Island and Tsim Sha Tsui on the Kowloon Peninsula side.

The first generation of buildings using what-so-called a curtain wall system can hardly be described as a full system which is usually of proprietary design. The pioneer systems were just external fa?ade/walling designed by local architects and with materials supplied by local

manufacturers. The common systems used by that time were in majority stick-type, spandrel and cover, or unit-in-frame systems, constructed of aluminum sections, sometimes incorporated with large areas of stone slabs to cover up solid walls. They were popular due to their highly adaptability, low cost, easy to design-and-install nature.

More deluxe commercial buildings were built in the late 70’s as the economy of Hong Kong growing hotter and hotter. Developers tended to request for systems with higher performance as the external envelop for their buildings, in terms both of appearance, material, construction and maintenance concerns.

Due to the relative lack of experience at that stage, the performance of these second generation curtain wall systems (from late 70’s to mid 80’s)could still hardly described as satisfactory. Problems like seepage, staining, deformation, deterioration and rapid aging of the jointing materials, were very common to many walling cases, often to a condition that made repair and maintenance almost impossible. The replacement of these walling systems not only costly, but also created great disruption to the normal utilization of the building users, and at the same time badly lowered the property value of the entire premises.

The third generation of curtain wall systems roughly started in the mid/late 80’s, by the time Hong Kong was experiencing her economic climax before the handing over of her sovereignty back

to China in 1997. Accommodated experience in the application of curtain wall systems in high-performance buildings contributed solidly in the process of perfecting these systems. Throughout the period, the design and production teams, as well as the manufacturers and the engineering supporting teams, were growing more mature in the mastering of the local situation and market. Most problems appeared in the previous cases have been much effectively taken care of. Systems of this generation are in general much more satisfactorily received by most users.

WHAT IS A CURTAIN WALL

Metal and glass curtain wall systems have found growing favour in modern architecture. They are easily distinguished from other types of claddings by their thin mullions of horizontal and vertical metallic bars surrounding an all glass or metal panel. The curtain wall system has evolved rapidly over the last two decades, especially with respect to weather control performance. The early systems presented frequent rain penetration problems; water stain patches would form on the outside or condensation on the inside mullion surfaces; glazing seals were sometimes pumped out of the rabbet of sealed double glazing window units. However, most of these difficulties were eventually overcome with improved detail design of the system components. Today, most curtain wall manufacturers offer a quality product line of components which can be used to create one of the best overall exterior wall systems.

A curtain wall system is a lightweight exterior cladding which is hung on the building structure, usually from floor to floor. It can provide a variety of exterior appearances but is characterized by narrowly spaced vertical and horizontal caps with glass or metal infill panels. These systems provide a finished exterior appearance and most often a semi-finished interior as well. They are also designed to accommodate structural deflections, control wind-driven rain and air leakage, minimize the effects of solar radiation and provide for maintenance-free long term performance. Most of today's metal curtain wall systems are constructed of lightweight aluminum or its alloys, although

some may be of steel.

COMMON TYPES OF CURTAIN WALL SYSTEMS

External wall with large area of glazed portion that carries no superimposed load except wind load is usually termed as curtain wall. Traditionally curtain wall consists of a metal frame system infill with vision or opaque panels, that serves to provide glazing for window openings as well as to cover-up structures like columns, slabs and beams, or sometimes even sections of solid wall.

There are many ways to serve the purpose, depending on a number of factors such as the design and budget for the project, layout and shape of the building structure, as well as other architectural or structural requirements. According to the American Architectural Manufacturers Association, curtain wall systems can be classified in five types, namely, the stick system, unit system, unit and mullion system, panel system, and the column-cover-and-spandrel system. However, due to the introduction of high-performance framing/articulation products and high-strength structural glass, some newer forms of curtain wall systems such as large-area glazed wall using spider clips, bow mullions, hangers or cable stiffeners as supports and connections, are new systems that cannot easily be classified using traditional concepts.

Stick system

Curtain wall in stick system is a cladding and exterior wall system which is hung on the building structure from floor to floor. It is assembled from various components to include steel or aluminum anchors, mullions (vertical load taking member), rails vision glass, spandrel panels, insulation and metal backing pans. For the fixing of the system, there are various hardware components such as anchors, connectors, brackets, cramps, setting blocks, corner blocks, gaskets and sealants etc.

This system has the following merits/demerits:

Merits

-Low cost, components can be made in standard design and stocked as proprietary product for use in bulk quantity.

-Shorter time for design and fabrication.

-Fairly easy to fit the shape and form of a building.

-Require relatively simple sections to form the mullions and the backing frame.

-The design of the infilling panels can be very flexible and form various combination using different materials to provide the appearance or fulfill other functional requirements.

-With the provision of the spandrel panel (the opaque portion) in the design, more colour or design options can be achieved.

-Installation of the system only requires simple tool like a manually operated pulley set-up.

-Easier to carry out replacement, alteration and maintenance. Demerits

-System is designed on a job-by-job basis

-More labour-intensive in the fixing and installation process

-Higher risk of leaking due to the existence of large amount of in-situ joints between mullion and panels.

-Involvement of large number of framing members coming from the mullion, transom or other framing parts that make the fixing at spot quite troublesome and inconsistent.

-Less fashionable for the design limited basically to monotonous grid without the elegance that other systems may achieve.

Unit System

Unit systems are composed of modulated panels that are fabricated in factory and delivered to site in one-piece for installation. The panels are fully provided with all the glazing and/or the spandrel panels, incorporated with the required insulation and other architectural features, thus requiring very limited second-fixed installation works on site. The panels are usually spanned in a floor-to-floor arrangement and may be designed in a number of standard/optional panels such as fully glazed, glazed with opaque panels, fully opaque in metal or stone slab, louvered panels, or other special modules like the corner or bayed units. In order to get the best benefit of using this system, units are often produced to an optimistic large size so as to minimize the number of units used.

This system has the following merits/demerits:

Merits

-Easy to install merely by securing the modulated panels onto the building exterior using fixing/connection devices which are usually very dimensionally flexible.

-Saving up a lot of manpower due to ease of installation.

-Higher performance units can be produced to meet stringent requirements due to better

control under factory environment.

-Preferably to be used in buildings with large walling area for the economy of scale in production as well as the elimination of countless assembly of minor components on site. Demerits

-It takes longer lead time to carry out the coordination, design and fabrication of the system/units.

-Require higher dimensional accuracy in the building structure for the fixing of the units.

-Lifting appliances may be required to assist the hoisting and installation of the large-sized walling units

-Difficult to carry out replacement or maintenance due to the interlocking nature of the modulated units.

Unit and mullion system

This is a combination of the stick system and the unit system and may be regarded as a compromise of the two. It is more suitable for use in medium-sized projects so as to balance the factors of lead time, ease of installation and economy of scale.

Panel system

A panel curtain wall system is similar to a unit system, the difference being that a panel system has homogeneous sheet or cast panel with few joints and may not have separate mullions. Unit systems are made up of smaller components fabricated together to form much complex panels that capable to perform heavier duties or other more specific requirements. However, due to the relative simplicity of the system, curtain wall of panel system design may not be able to fulfill the usual requirements most high-rise buildings required under Hong Kong’s environment. Its use is therefore more limited to certain kinds of buildings like those of standardized design for low-income classes or for buildings of industrial purposes. In this case, the panels can be constructed of sheet materials and manufactured in large quantity in very low cost.

Column-cover-and-spandrel system

Column-cover-and-spandrel system consists of column covers, which are usually made of alloyed aluminum, metal sheet or other laminated/fibre-reinforced sheet, and with glazing components and spandrel panels that fit between them. It resembles certain similarity to a unit-and-mullion system except that the structure of the building is exemplified by the column covers.

With the exception of the stick system and the unit system, other curtain wall systems are seldom used in Hong Kong.

Structural glazing system

The merit of using structural glazing system as external wall is to minimize the unglazed elements as much as possible, leaving glass panel almost as the only glazed surface on the wall. This can be done by providing larger mullion supports which span outward away frm the structural floor of a building. Special clamping devices such as a spider bracket can be used to hold the glazing panel in position. Structural sealant is used to seal up the gap between the glazing panels.

DESIGN PRINCIPLES FOR EXTERNAL WALL

A building enclosure may be broadly defined as a set of interconnecting elements which separate the outside from the inside. These elements would include exterior walls, a roof, other components such as windows and doors, and sometimes exposed floors. The function of a building enclosure is to control the penetration of snow, wind, rain and sun to the inside and to contain the desired indoor climate. The enclosure must meet many individual requirments but for the purpose of this paper they are limited to the following six:

control of air flow,

control of heat flow,

control over the entry of rain and snow,

control of sunlight and other forms of radiant energy,

control of water vapour diffusion,

accommodation of building movements.

The requirement for air tightness and consequently air leakage control is met by most curtain wall systems because the air barrier of the wall is inherent in the structural properties of glass and aluminum or steel tubes that comprise the system. The continuity of the air barrier (Figure 1) is achieved by the continuity of the glass panel through the air seal at the shoulder flanges of the tubular mullion, and through the aluminum section to the other flange surface. The air seal between the lower shoulder flange of the curtain wall mullion and the metal pan of the spandrel panel provides continuity of air tightness to the air barrier metal pan and on to the next mullion connection. Such assemblies are regularly tested using air pressure to determine the structural properties of the glass, metal, and seals and to determine the equivalent leakage area (ELA) that remains. In addition, the Architectural Aluminium Manufacturers Association imposes upon its members many other requirements including a specification that the system must not leak more than.30L/sperm2 of wall at a pressure difference equivalent to a 40 km/h wind.

Thermal Insulation (Control of heat flow)

The control of heat flow is generally achieved through the use of insulation. Although it is not apparent from the exterior, the curtain wall system uses considerable insulation usually behind spandrel glass or any opaque panels. Because of the materials used in the structure, i.e., glass and metal, which are highly conductive, the system must also contend with potential condensation on the interior surfaces. To curtail this effect, most curtain wall systems incorporate two distinct features: first, a sealed double glazed window or an insulated metal pan and second, a thermally broken mullion, usually with a PVC plastic insert and more recently, a foamed-in-place polyurethane connection. A sealed double glazed window unit can accommodate an indoor humidity up to about 35% at an outdoor temperature of -25 ° C with little condensation appearing on the glass. Similarly, the thermal break in the aluminum or steel mullion ensures that the surface

temperature of the structural mullion will remain well above the dew point temperature of the air for most building types, except for high humidity indoor environments such as in swimming pools or computer centers. The thermal break also ensures that the structural mullion is thermally stable, that is, not subject to extremes of expansion and contraction.

MAINTENANCE CONSIDERATION

Maintenance for curtain wall is a long-term consideration involving both the quality of design, control during construction and adequate maintenance throughout the life span. Once failure occurs in the curtain wall it will be very expensive to have the defects rectified and at the same time causing great disturbance to the building users. Below are some common problem sources where failures usually occur.

1.D esign failure – selection and appropriateness of the system, non-compliance to design and performance standards, imperfection in the jointing design and detailing, improper use of materials etc.

2.C onstruction and structural failure –wrong location or method of fixing, improper anchorage and connection provision (including failure in welding), failure in the walling components, unpredicted deflection or deformation appears in the background structure, poor supervision and workmanship.

3.A ging and deterioration –discolouring and surface damaging due to weather action; corrosion due to air pollution, acid rain, or electro-chemical effect to dissimilar metals; aging and hardening of the glazing compound or sealing gasket, deteriorating of the insulating materials that lead to further dampening of the walling materials/components, disfiguring or loosening of the fixing and connections, loosening or broken-off of the glazing or other fitting items.

Curtain wall systems should be inspected regularly after they have been installed in buildings. Proper maintenance and repair are essential to keep them in a safe condition. Inspection

arrangement should be made in particularly before and after typhoons. The below signs are recommended to observe closely during each inspection.

-Sign of distress and deterioration of the entire wall system,

-cracked, loose or missing glass panels,

-bulging, bowing, separation, delamination, rotation, displacement of panels,

-marks of water, staining and rust,

-damaged and missing parts, corrosion, loosening or other defects,

-extrusion, wrinkle, split, missing or other signs of deterioration of the sealing materials.

-moisture appears around or behind the curtain wall.

CONCLUSION

The application of curtain wall systems in super-highrise buildings is a big topic. Within the scope of this paper it can only cover a very little of the key issues. Having witnessed the evolution of using curtain wall in Hong Kong for the past 2 to 3 decades, a general trend, as summarized below, can be observed.

-Starting from low-cost, local-design and manufactured walling products in the early systems to the imported, deluxe, tailor-designed proprietary systems in recent years.

-Starting from simple requirements fulfilling just very basic functional needs of buildings to very specialized products or systems that can meet any stringent requirements as set by designer, engineers or environmental experts.

-The old systems were mainly stick systems due to more simple in design and production. Though labour-intensive, the relatively much cheaper labour cost at that time still made it worked acceptably. Contemporary systems are using mainly unit systems that make installation very easy and labour saving, though the design quality and coordination with other building activities are much more demanding.

-The old systems that have been used in the first and second generations often inherited with quite a lot of design imperfections and latent defects; while new systems are more reliable, some can be regarded as almost maintenance-free.

Traditional external walling methods using applied-onto products such as tile or spray-on coating are still dominating in Hong Kong. However, it is notable that the use of curtain wall is gaining its popularity quite rapidly among designers and developers due to its unreplaceable attractiveness as well as slim and fashionable appearance.

Further development and improvement in the use of curtain wall systems is an ongoing process in Hong Kong. The areas of improvement may be aiming at the development of more specific functioned, more reliable and long-life systems. Such targets may be achieved by the use of more advanced glass products, sealing compounds, gaskets or in the development of more sophisticated connecting systems; as well as the introduction of other additional functions that curtain wall may take up like the incorporation of photo-cell onto panels of wall, the providing of automatic/robotic machine in the system for external wall cleansing, or curtain wall capable to perform light show at night. Meanwhile, the continual improvement of workmanship and refinement of work detailing in particular to the areas directly in touch with the building structure or other building finishes, is a prime concern to the ensurance of a good curtain wall system, that sometimes project executives may easily overlooked.

中文译文：

超高层建筑幕墙系统的结构与性能

香港城市大学，建筑科学与技术部

Raymond WM Wong

引言

几十年来超高层建筑的建设在香港一直非常活跃。比如近期著名项目 50 层高的宏利大厦，62 层高的长江集团中心，80 层高的“中心”大厦，有 88 层高的国际金融中心，以及最近的一些超过 60 层楼高的住宅，这些项目无一例外都是采用幕墙作为他们的外部围护结构。

高层建筑如何采用薄壁外部围护结构一直是一个挑战设计师和建筑工的难题，特别是在成本、能源、水密性、安装性、尺寸方面、结构的稳定性、与其它建筑构件接口的搭配、维修等方面。笔者想利用香港的经验，来介绍一些当地薄壁幕墙系统设计和安装的实践和总结。

使用幕墙的香港建筑

自 1970 年始香港经济腾飞由传统的制造业进入了工业经济时代同时香港致力于把自己打造成一个世界知名的金融中心，高层建筑开始在香港的天际线涌现。在那时高层建筑主要集中在商业区如香港岛的中央和九龙半岛的尖沙咀一面。

第一代所谓的幕墙系统难以被描述为一个完整的系统。先锋系统通常是由当地建筑师设计外墙或墙面以及由当地制造商提供材料的设计。当时的通用系统大多数由铝部分构成有时并入大面积的石板掩盖其实心墙。由于其适应性强、成本低、易于设计和安装的性质非常地受欢迎。由于上世纪 70 年代香港经济越来越热更豪华的建筑开始出现。

开发商往往要求建筑外部围护系统在外观、材料、施工和保养担忧等方面具有更高的性能。

在这个阶段，由于相对缺乏经验，这些第二代幕墙系统（从 70 年代末到 80 年代中期）的表现仍然很难令人满意。存在防渗染色、变形、变质和拔节等快速老龄化问题。许多墙面往往由于维修的条件的限制维修几乎是不可能的。这些墙面的更换，不仅成本高，而且影响建设用户的正常使用而且严重降低了整个物业的属性值。

图 1 中环及香港尖沙咀九龙区

第三代幕墙系统的大致始于 80 年代末中期，因为当时香港在 1997 年交出她的主权回到中国前经历了经济高潮。高性能建筑在幕墙系统中的应用容纳体验对于完善这些系统贡献巨大。在整个期间，设计和生产团队以及制造商和工程配套队伍对当地情况的掌握变得越来越成熟，以前案件中出现的大部分问题都被有效地解决。这一代系统被用户广泛接受.

什么是幕墙

现代建筑越来越青睐于金属和玻璃幕墙系统。他们由全玻璃或金属板包裹容易识别的金属框构成幕墙系统。幕墙系统迅速发展了近二十年，特别是在气候控制性能等方面。由于经常下雨系统存在渗透问题，水渍补丁在内竖框表面的外侧形成。但是大多数的这些困难通过系统细节设计的改进最终被克服。在今天大多数的幕墙制造商可通过其高质量的生产线提供零部件，这些零部件可以被用来创建最佳的整体外墙系统。幕墙系统是一种挂在建筑结构的轻量级覆盖外墙，通常它可以提供多种外观，这些系统提供成品和半成品外观以适应结构变形、控制风力驱动的雨和空气泄漏、减少太阳辐射

的影响并提供了长期免维护的性能。虽然有些人可能认为金属幕墙是钢的但今天的大多数金属幕墙系统的构造采用轻质铝或其合金。

幕墙系统的常见类型

大面积外墙，除携带风载荷无其他附加荷载的釉面部分通常称为幕墙。传统幕墙是一个填充透明或不透明的面板的金属框架系统，但是需要提供玻璃、窗户来掩盖像柱、板和横梁或实心墙，甚至部分的结构。

有许多方法可以达到这个目的，这取决于许多因素例如设计和项目预算，布局和建筑结构的形状，以及其它建筑或结构要求。根据美国建筑制造商的标准，墙系统可分为 5 种类型，即在构件幕墙的系统、装置系统、装置和竖框的系统、面板系统、列盖-拱肩系统。然而，一些较新形式的幕墙系统由于引进高性能帧关节产品和高强度结构玻璃，是不能很容易地使用传统的观念来分类的，如大面积采用蜘蛛剪辑、低头竖框、衣架或电缆作为加强筋来支撑和连接的釉墙壁。

构件幕墙系统

幕墙构件幕墙系统是挂在建筑物的包层和外墙的系统结构。它是由各种部件包括钢或铝锚、竖框（垂直负载承受件）、导轨视力玻璃、窗间墙、铝绝缘和金属背衬盘组成。对于该系统的固定有各种各样的硬件部件如锚、连接器、支架、抽筋、设置块、角块、垫片和密封胶等。

该系统具有以下优点/缺点：

优点：成本低，可使用散装的标准原件；更短的设计和制造时间；

更加容易地适合建筑物的形状和形式；

形成竖框和背架的部分相对简单；

充填面板的设计非常灵活还可以形成各种组合；

使用不同的材料外观；

由于提供了拱肩面板（不透明部分）的设计，更多颜色的设计方案可以实现；安

装系统只需要建立一个像手动操作滑轮的简单工具；更容易进行更换，改造和维

修。

缺点：

系统设计上的作业，通过作业为基础；劳动密集型的固定和安装过程；由于大量原位之间的接缝的存在更高的漏水风险；

大量框架构件从竖框、梃未来或介入其他框架部分，使固定在现场相当麻烦和不一致。

图 2 - 用构件幕墙系统项目- 68 层高的信兴广场深圳（左）和网关在尖沙咀

翠。特写看看墙上的细节（中心图），信兴广场（上图）和网关（下）单元式系

统

单元式系统是由那些在制造工厂制造的调制板网进行一体式的安装。该小组提供所有的玻璃和拱肩板、所需的隔热及其他建筑特色，从而需要在第二工程现场进行固定安装。该面板可以设计成一些标准或可选版如全玻璃、釉面不透明板、金属或石板、完全不透明的百叶窗式面板等。本系统中为了得到最佳使用效益，单元式往往预留一个乐观的大尺寸，以减少使用单元式的数量。

该系统具有以下优点/缺点：

优点

调板只是固定到建筑外观易于安装，通常是非常灵活的尺寸固定或连接设备；

由于安装方便，节省了大量的人力；在工厂环境下由于更高的的要求控制使得

性能更高；生产大面积墙体规模经济建筑物可消除现场细琐的装配。

缺点

这些系统跟单元需要较长的时间来进行协调、设计和制造；建筑结构为单元式

的固定需要较高的尺寸精度；墙壁单元吊装和安装需要大型起重机械协助；

因其互锁性质难以进行更换或维护；

单元式和竖框系统这是构件幕墙系统和单元系统的组合，并且可被视为两者的相互制约。它更适合于中型项目使用，由于平衡的铅、时间等因素更加易于安装和规模生产。面板系统

一个板幕墙系统类似于一个单元系统，不同之处在于面板系统具有均匀的片或浇铸板形成的个关节，可能没有单独的窗棂。单元式系统由更小的组件装配在一起形成许多复合板能够执行更重的或其他更具体的要求。然而，由于该该系统的相对简单性，幕墙系统的板设计未必能够满足香港环境下所需的最高层建筑要求。其因此，使用仅限于某些种类的建筑的标准化原件于收入阶层或用于工业用途的建筑物。在这种情况下，该板可以是构成的片材，其生产成本更加低廉

列盖和-拱肩系统

列盖和-拱肩系统，其通常由合金化的铝，金属片或其他层压/纤维强化片组成的柱罩及玻璃组件和拱肩板填充其间。竖框系统不同的是建筑物的结构是与列盖相似的单元式。除了构件幕墙子系统和单元系统，其他幕墙系统很少在香港使用。结构性装配系统

使用结构玻璃系统作为外墙的优点是尽可能地减少无釉元素，仅留玻璃面板墙壁上的唯一上釉表面。这可以通过支撑竖框的外侧远离跨越做建筑物的结构层。特殊的夹紧装置，如蜘蛛支架可用于按住玻璃面板的位置。用于密封玻璃面板之间差距的结构密封胶。

图 4

外墙设计原则

建筑物外壳可以广义地定义为一组从内侧到外侧相互连接的单独的元素。这些要素包括外墙、屋顶、其他部件如门窗、有时露出地面。建筑围护的功能是控制的雪、风、雨和阳光渗透到里面以及调节所需的内气候，外壳须满足许多个性化需求，但对本文来说被限制在以下六个：

控制空气流控制热量

流控制雨雪的进入

控制阳光和其他形式的辐射能量

控制水蒸汽扩散

因此漏风控制的要求是由最满足帷幕墙系统建筑运动的气密性，因为壁的空气屏障的结构特性是玻璃以及铝或组成该系统的钢管。空气屏障的连续性（图 1）由通过空气密封的玻璃面板的肩部凸缘管状的竖框连续性来实现，并通过铝延伸到凸缘表面上。空气密幕墙竖框的下肩法兰及拱肩的金属盘面板将续性的空气阻挡提供更好的气密性。结构需定检测玻璃、属性和封件并确定等效漏区（ELA）的属性仍然存在。此外，铝