英文翻译：超高层建筑结构横向风荷载效应

1、武汉科技大学本科毕业设计外文翻译Across-wind loads and effects of super-tall buildings and structuresGU Ming & QUAN Yong SCIENCE CHINA Technological Sciences,2011,54(10):25312541超高层建筑结构横向风荷载效应顾明 全勇中国科学 技术科学，2011，54(10):25312541摘 要随着建筑高度的不断增加，横

2、向风荷载效应已经成为影响超高层建筑结构设计越来越重要的因素。高层建筑结构的横向风荷载效应被认为由空气湍流，摇摆以及空气流体结构相互作用所引起的。这些都是非常复杂的。尽管30年来，研究人员一直关注这个问题，但横向风荷载效应的数据库以及等效静力风荷载的计算方法还没有被开发，大多数国家在荷载规范里还没有相关的规定。对超高层建筑结构的横向风荷载效应的研究成果主要包括横向风荷载的动力以及动力阻尼的测定，数据库的开发和等效静力风荷载的理论方法的等等。在本文中，我们首先审查目前国内外关于超高层建筑结构风荷载的影响的研究。然后我们在阐述我们的研究成果。最后，我们会列举我们研究成果在超高层建筑结构中应用的的案例

3、。1 引言随着科技的发展，建筑物也越来越长、高、大，越来越对强风敏感。因此，风工程研究人员面临着更多新的挑战，甚至一些未知的问题。例如，超高层建筑现在在全世界普遍流行。高度为443米的芝加哥希尔斯塔保持了是世界上最高建筑物26年的记录，现在还有几十个超过400米的超高层建筑被建造。828米高的迪拜塔已经建造完成。在发达国家，甚至有人建议建造数千米的“空中城市”。随着高度的增加，轻质高强材料的使用，风荷载效应特别是具有低阻尼的超高层建筑横向风动力响应将变得更加显著。因此，强风荷载将成为设计安全的超高层建筑结构中的一个重要的控制因素。达文最初引入随机的概念和方法应用发哦顺风向荷载效应的建筑物和其他

4、结构的抗风研究。之后，研究人员完善了相关的理论和方法，并且主要的研究成果已经反映在一些国家的结构设计荷载规范里。对现代超高层建筑结构，横风向风荷载的作用可能已经超过顺风向荷载效用。虽然研究人员已经关注这个方向已经30多年了，但能够被广泛接受的横风向荷载数据库以及等效静力荷载的计算方法还没有形成。只有少数国家在他们的荷载规范里有相关的内容和规定。因此，研究超高层建筑结构横风向风振和等效静力荷载在超高层建筑设计领域内具有重要的理论意义和实用价值。 2 研究现状2.1 横风向荷载及作用机制 过去的研究主要集中在横风向荷载机制。郭指出横风向荷载的激发主要由于被公认为空气动力阻尼的尾

5、流、空气湍流以及风荷载耦合作用。索拉里认为横风向荷载主要由于尾流的原因所引起。卡里姆声称横风向的效应主要是由分离剪切层和尾流波动引起的横向均匀压力波动所引起的。目前，高层建筑横风向荷载机制已被人为是流入湍流激发、尾流激发、以及气动弹性影响。湍流以及尾流激励一般是外部空气动力，在本文章中，所涉及的统称为空气动力。同时，气体的弹性效应可以被认为是气体动力阻尼。横风向气体动力不再像顺向风一样符合准稳态假设。因此，横向风荷载谱不能直接作为一个脉动风速谱。对不稳定风压力来说，风洞试验技术是目前研究横向风动力的主要技术。风洞试验技术主要包括气体弹性模型试验、高频力平衡试验以及对多点压力测量的刚性模型实验技

6、术。用横风向外部动力，横风向气动阻尼，横向风响应和建筑结构等效静力风荷载的数据可以对超高层建筑结构进行计算。2.2 横风向气动力 如上所述，横风向气动力基本上可以通过以下途径获得：从气动弹性模型在一个风洞的横风向响应确定横风向气动力；通过刚性模型风压空间一体化获得横向风动力；使用高频测力天平技术测量基底弯矩来获得广义的气动力。 2.2.1 从气动弹性模型的动态响应确定横风向气动力这种方法采用的是气动弹性模型的横风向风振响应，结合动态特性的模型识别横风向气动力。墨尔本对对一系列圆形、方形、六角形、多边形沿高度分布进行气动弹性模型风洞试验。然而进一步试验表明您横风向气动阻力与气

7、动力混合在一起，使他难以准确地提取气动阻尼力。因此，该方法很少使用。2.2.2 风压积分法 研究人员建议用风压积分法获取更准确的高层建筑横风向气动力。伊斯兰等人采用这种方法得到横风向气动力，陈等人研究了典型建筑结构在不同风场条件横风向气动力。影响横风向气动力的因素主要有湍流强度、湍流尺度。湍流强度被发现扩大带气动力和降低峰值。然而,湍流强度被认为对总能量几乎没有影响。因此,研究人员在某种程度上已经意识到了在风力条件定量规则的变化横风气动力。梁等人使用这种方法检查了建筑物上的典型矩形边界层风洞横风向气动力，从而提出高大的建筑物的经验公式和横风向动态响应模型。结果表明, 横风向

8、湍流对于横风向气动力的贡献比那些激励要小的多。基于大量的结果,导出横风向湍流激励和激发后的PSD计算公式。第一广义的横风向气动力计算可以通过在刚性建筑模型整合压力分布得到，这是该方法一个重要的优越性。然而,考虑到在这类方法需要大量的大规模的结构测压，同步测量风压是很难实现的。此外,对于建筑和结构复杂的配置,准确的风压分布和空气动力难以使用这种方法。2.2.3 高频测力平衡技术 与压力测量技术相比，高频力平衡技术对于得到总气动力有其独特的优势，检测和数据分析过程都很简单。因此这项技术通常应用于初期设计阶段的建筑外观的选择。目前这项技术被广泛应用于作用在超高层建筑结构的全风荷载以及动力响

9、应计算。高频力平衡技术自从1970年已经逐渐发展起来。赛马可等人是第一批把此技术应用到模型测量的人。他们最初提出平衡模型系统应有一个比风力频率更高的固有频率。由常和达文发展的平衡技术标志着平衡设备的成熟。 卡里姆进行了一项实验研究。对于在城市和郊区具有不同截面形式的高层建筑的横风向气动力研究表明对于建筑物风的不确定以及结构参数对横风向空气动力的设计有很小的影响并且顺风向和横风向气动力或扭矩之间的联系时微不足道的。但横风向动力和扭矩之间的联系是非常密切的。这个结论对于三维方向精确的风荷载模型是很重要的。特别是石和全等人做了一系列关于矩形建筑的边率，建筑物横截面形状，建筑的面率的效应以及

10、用五元平衡的高层建筑横风向动力设计的风域条件。事实上，基于大量的风隧道检测结果典型高层建筑横风向气动力系数的公式已经被我们建立了。2.3 横风向气动阻尼 1978年卡里姆对基于气动弹性模型技术和风压积分法的高层建筑横风向动力响应做了一次调查研究。他指出由在一定范围内风压力测试获得的横风向气动力计算而得到的横风向风振响应总是比那些相同建筑模型的气动弹性模型要小。这个重要的研究成果使得研究人员认识到横风向气动负阻尼的存在。 后来，研究人员对这个问题进行了大量的研究并且找到了有效的方案来确定气动阻尼。第一种方法是通过比较基于来自刚性模型试验和气动弹性模型试验的气动力所得到的到哪个

11、台响应。第二种方法是从由气动弹性模型或强迫振动模型所得到的总气动力中分离出气动阻力。第三种方法是从气动弹性模型分离气动阻尼的的识别方法。此外，研究人员意识到风因素的影响规律。这些因素包括结构形状、结构动力参数、风条件等等。卡里姆等人是第一批提出通过比较来确定气动阻尼的方法。陈等人采用这种技术来研究横风向效应和高层建筑结构的动态阻尼并提出了一个气动阻尼公式。 史迪克最初制造了一批测定总气动力、气动阻尼力与气动力的强迫振动测量设备。他测量高层建筑模型基底弯矩是通过一个专门的设计装置产生振动所产生的有关的气动力从总气动力脱离进而分解为气动应力和气动阻尼力获得气动阻尼。柯伯试图对谐波振动建筑

12、模型测量风压获得总气动力。然后用类似史迪克的方法计算空气阻尼。这种方法的优点是真实的建筑特性并非必须被考虑到。这种方法更方便更实用，特别是在推广实验结果。这种方法的的主要缺点是它需要复杂的设备，尤其是直到现在多元耦合装置是不可用的。 确定气动阻尼的随机振动响应的气动弹性模型课采用适当的系统识别技术，其中包括频域法，时域的方法以及时域频域的方法。在这些方法中随机减量法、时域方法被广泛采用以确定高层建筑的气动阻尼。杰瑞介绍随机减量法来识别结构阻尼。马克采用随机减量法确定高层建筑顺横风向气动阻尼。他们分析了影响建筑长宽比、边比、气动阻尼、结构阻尼。田村等人用随机减量技术确定超高层建筑气动阻

13、尼。全等人通过实验确定在不同的风领域具有不同结构中阻尼方形截面的横风向气动阻尼，并得出了一个经验公式。这些研究成果已通过相关的中国规范。秦和谷是第一个引入随机空间识别方法于气动参数的确认的研究人员。这些气动参数包括大跨度桥梁气动刚度和阻尼。于随机变量法相比，随机空间识别方法具有更多的优点。它能克服随机变量法的弱噪音抵抗力和需要大量实验数据的缺点。秦采用这种方法来确定高层建筑的气动阻尼。2.4规范的实用性 如上所说，虽然研究者一直关注高层建筑风荷载超过30年了，但被广泛接受的横风向风荷载数据库和计算方法，等效静力风荷载尚未开发。此外，只有少数国家采用相关的规定和代码。于其他国家相比，日

14、本建筑协会提供了计算高层建筑结构横风向荷载的最好方法。然而公式的横风向代码知适用于高层建筑高宽比小于六，这似乎很难满足实际需要。而且此方法在这种方法里气动阻尼没有被考虑。 在目前的中国建筑结构荷载规范只提供了一个简单的方法来计算涡激共振的高耸结构，而一般不适用于高层建筑结构抗风设计。在题为“高层建筑钢结构设计详细说明”里，我们的研究成果已经通过。2.5 总结 随着建筑高度不断增加，横风向荷载效应已经成为超高层建筑结构设计的重要因素。目前，对超高层建筑结构横风向荷载的研究主要包括横风向风荷载的机制，横风向气动力、气动阻尼和在规范中的应用。因此我们的一些研究成果主要有典型建筑结

15、构的横风向力，气动阻尼以及在中国规范的应用。最后介绍了典型的案例，在这个案例中建造更高层建筑的趋势预示着风工程研究人员将面临着更多更新的挑战，甚至到现在他们都没有意识到的问题。因此需要更多地努力去解决工程设计问题，同时进一步发展风工程。附件：英文原文Across-wind loads and effects of super-tall buildings and structuresGU Ming & QUAN YongAbstractAcross-wind loads and effects have become increasingly important factors in

16、the structural design of super-tall buildings and structures with increasing height. Across-wind loads and effects of tall buildings and structures are believed to be excited by inflow turbulence, wake, and inflow-structure interaction, which are very complicated. Although researchers have been focu

17、sing on the problem for over 30 years, the database of across-wind loads and effects and the computation methods of equivalent static wind loads have not yet been developed, most countries having no related rules in the load codes. Research results on the across-wind effects of tall buildings and st

18、ructures mainly involve the determination of across-wind aerodynamic forces and across-wind aerodynamic damping, development of their databases, theoretical methods of equivalent static wind loads, and so on. In this paper we first review the current research on across-wind loads and effects of supe

19、r-tall buildings and structures both at home and abroad. Then we present the results of our study. Finally, we illustrate a case study in which our research results are applied to a typical super-tall structure.1 Introduction With the development of science and technology, structures are becoming la

20、rger, longer, taller, and more sensitive to strong wind . Thus, wind engineering researchers are facing with more new challenges, even problems they are currently unaware of. For example, the construction of su-per-tall buildings is now prevalent around the world. The Chicago Sears Tower with a heig

21、ht of 443 m has kept the record of the worlds tallest building for 26 years now. Dozens of super-tall buildings with heights of over 400 m are set to be constructed. Burj Dubai Tower with a height of 828 m has just been completed. In developed countries,here are even proposals to build “cities in th

22、e air” with thousands of meters of magnitude. With the increase in height and use of light and high-strength materials, wind-induced dynamic responses, especially across-wind dynamic responses of super-tall buildings and structures with low damping, will become more notable. Hence, strong wind load

23、will become an important control factor in designing safe super-tall buildings and structures. Davenport initially introduced stochastic concepts and methods into wind-resistant study on along-wind loads and effects of buildings and other structures. Afterward, researchers developed related theories

24、 and methods 817, and the main research results have already been reflected in the load codes of somecountries for the design of buildings and structures 1823. For modern super-tall buildings and structures, across-wind loads and effects may surpass along-wind ones. Al-though researchers have been f

25、ocusing on the complex problem for over 30 years now, the widely accepted data-base of across-wind loads and computation methods of equivalent static wind loads have not been formed yet. Only a few countries have accordingly adopted the related con-tents and provisions in their codes 18, 20. Therefo

26、re, studying across-wind vibration and the equivalent static wind loads of super-tall buildings and structures is of great theoretical significance and practical value in the field of structural design of super-tall buildings and structures. The current paper thus reviews the research situation of a

27、cross-wind loads and effects of super-tall buildings and structures both at home and abroad. Then, the research results given by us are presented. Finally, a case study of across-wind loads and effects of a typical super-tall structure is illustrated.2 Research situation 2.1 Mechanism of across-wind

28、 loads and effects Previous researches focused mainly on the mechanism of across-wind load. Kwok 2426 pointed out that across-wind excitation comes from wake, inflow turbulence, and wind-structure interaction effect, which could be recog-nized as aerodynamic damping. Solari 27 attributed the across-

29、wind load to across-wind turbulence and wake exci-tations, considering wake as the main excitation. Islam et al. 28 and Kareem 13 claimed that across-wind responses are induced by lateral uniform pressure fluctuation due to separation shear layer and wake fluctuation. Currently, the mechanism of acr

30、oss-wind load on tall buildings and struc-tures has been recognized as inflow turbulence excitation, wake excitation, and aeroelastic effect. Inflow turbulence and wake excitation are essentially the external aerody-namic force, which is collectively referred to in the present paper as aerodynamic f

31、orce. Meanwhile, aeroelastic effect can be treated as aerodynamic damping. Across-wind aero-dynamic force no longer conforms to quasi-steady assump-tion as the along-wind one; thus, the across-wind force spectra cannot be directly expressed as a function of inflow fluctuating wind velocity spectra.

32、Wind tunnel test tech-nique for unsteady wind pressures or forces is presently a main tool for studying across-wind aerodynamic forces. The wind tunnel experiment technique mainly involves the aeroelastic building model experiment technique, high fre-quency force balance technique, and rigid model e

33、xperiment technique for multi-point pressure measurement. Using data of across-wind external aerodynamic force and across-wind aerodynamic damping, across-wind responses and the equivalent static wind load of buildings and structures can be computed for the structural design of super-tall buildings

34、and structures.2.2 Across-wind aerodynamic force As stated above, the across-wind aerodynamic force can be obtained basically through the following channels: (i) iden-tifying across-wind aerodynamic force from across-wind responses of an aeroelastic building model in a wind tunnel; (ii) obtaining ac

35、ross-wind aerodynamic force through spa-tial integration of wind pressure on rigid models; (iii) ob-taining generalized aerodynamic force directly from meas-uring base bending moment using high frequency force balance technique. 2.2.1 Identification of across-wind aerodynamic force from dynamic resp

36、onses of aeroelastic building model This method employs across-wind dynamic responses of the aeroelastic building model, combining the dynamic charac-teristics of the model to identify across-wind aerodynamic force. Saunders 29, Kwok 24, Kwok and Melbourne 30, Kwok 25, and Melbourne and Cheung 31 pe

37、rformed aeroelastic model wind tunnel tests on a series of circular, square, hexagon, polygon with eight angles, square with reentrant angles and fillets, and tall or cylindrical structures with sections contracting along height. However, further studies showed that across-wind aerodynamic damping f

38、orce and aerodynamic force mixed together make it diffi-cult to extract aerodynamic damping force accurately. As such, the method has been seldom used. 2.2.2 Wind pressure integration method Researchers have recommended wind pressure integration to obtain more accurately the across-wind aerodynamic

39、forces on tall buildings. Islam et al. 28, Cheng et al. 32, Nishimura and Taniike 33, Liang et al. 34, 35, Ye 36, Tang 37, Zhang 38, and Gu et al. 39 adopted this method to obtain across-wind aerodynamic forces on tall buildings and structures. Cheng et al. 32 experimentally studied across-wind aero

40、dynamic forces of typical buildings under different wind field conditions and derived empirical formulas for the power spectrum density (PSD) of the across-wind aerodynamic force reflecting the effects of tur-bulent intensity and turbulent scale. Turbulent intensity was found to widen the bandwidth

41、of PSD of the across-wind aerodynamic force and reduce the peak value. However, tur-bulent intensity was determined to have almost no effects on total energy. Thus, researchers have recognized the quantita-tive rules of variation of across-wind aerodynamic force with wind condition to some extent. L

42、iang et al. 34, 35 examined across-wind aerodynamic forces on typical rectangular buildings in a boundary layer wind tunnel using this method, thus proposing empirical formulas for PSD of across-wind aerodynamic forces of tall rectangular buildings and an ana-lytical model for across-wind dynamic re

43、sponses. Ye 36 and Zhang 38 decomposed across-wind turbulence excita-tion and vortex shedding excitation in across-wind aerody-namic forces on typical super-tall buildings. The resultsshowed that the across-wind turbulence contributed much less to across-wind aerodynamic force than the wake excita-t

44、ion. Based on a large number of results, we derived PSD formulas for the across-wind turbulence excitation and the wake excitation, and further derived a new formula for the across-wind aerodynamic force. The first- and higher-mode generalized across-wind aerodynamic forces can be calculated through

45、 the integra-tion of pressure distribution on rigid building models, which is an important advantage of this method. However, given the need for a large number of pressure taps for very large-scale structures in this kind of method, synchronous pressure measurements are difficult to make. Moreover,

46、for buildings and structures with complex configurations, ac-curate wind pressure distribution and aerodynamic force are difficult to obtain using this kind of method. 2.2.3 High frequency force balance technique Compared with the pressure measuring technique, high fre-quency force balance technique

47、 has its unique advantage for obtaining total aerodynamic forces. The test and data analy-sis procedures are both very simple; hence, this technique is commonly used for selection studies on architectural ap-pearance in the initial design stage of super-tall buildings and structures. Currently, this

48、 technique is widely used for total wind loads acting on super-tall buildings and structures, and for dynamic response computation as well. The high frequency force balance technique has been gradually developed since the 1970s. Cermak et al. 40 were the first to use this technique for building mode

49、l measurement. They initially pointed out that the bal-ance-model system should have a higher inherent frequency than the concerned frequency of wind forces. The five-component balance developed by Tschanz and Daven-port 41 marked the maturity of balance facility. Kareem conducted an experimental st

50、udy on across- wind aerodynamic forces on tall buildings with various sec-tion shapes in urban and suburban wind conditions. The research showed that for the buildings with aspect ratios of 46, uncertainties of wind and structural parameters have small effects on PSD of the across-wind aerodynamic f

51、orce, and the correlation between the along-wind aerodynamic force and the across-wind aerodynamic force or the torsion moment is negligible, but there is a strong correlation be-tween the across-wind aerodynamic force and the torsion moment. This conclusion is important for the development of three

52、-dimensional refined wind load model. Particularly, Gu and Quan 42 and Quan et al. 43 made detailed stud-ies on the effects of the side ratio of a rectangular building, cross-section shape of a building, aspect ratio of a building, and wind field condition on the PSD of the across-wind aerodynamic f

53、orce of tall buildings using a five-component balance. In fact, based on a large number of wind tunnel test results, formulas for across-wind aerodynamic force coeffi-cients of the typically tall buildings have been derived by us and other researchers, some of which are listed in Table 1. In additio

54、n, in Table 1, the formula derived by Gu and Quan 42 has already been adopted in related design codes in China.2.3 Across-wind aerodynamic damping In 1978, Kareem 44 performed an investigation on across-wind dynamic responses of tall buildings based on both of the aeroelastic model technique and the

55、 wind pres-sure integration method. He found out that the across-wind dynamic responses calculated with the across-wind aerody-namic forces obtained from the wind pressure tests at a certain test wind velocity range were always smaller than those of the aeroelastic model of the same building model.

56、This important result made researchers realize the existence of across-wind negative aerodynamic damping.Subsequently, researchers carried out numerous studies on the problem and developed effective methods for identi-fying aerodynamic damping. The first kind of method ob-tains aerodynamic damping b

57、y comparing the dynamic re-sponses computed based on the aerodynamic forces from rigid building model tests and those from aeroelastic model tests. The second one separates aerodynamic damping force from the total aerodynamic force measured from aeroelastic building models or forced vibration buildi

58、ng models. The third kind employs identification methods for extracting aerodynamic damping from random responses of aeroelastic models. Moreover, researchers realized the effect law of factors, including structural shape, structural dynamic pa-rameters, wind conditions, and so on, on aerodynamic da

59、mping, Isyumov et al. 45 were the first researchers to propose a method for aerodynamic damping through com-paring responses from a rigid building model test using HFFB technique with those of an aeroelastic model of the same building. Cheng et al. 46 adopted the method to study across-wind responses and aerodynamic damping of tall square buildings and proposed an aerodynamic damping formula.Steckley