建筑外文翻譯--超高層建筑結(jié)構(gòu)橫向風荷載效應

1、<p>　　本科畢業(yè)設計外文翻譯</p><p>　　超高層建筑結(jié)構(gòu)橫向風荷載效應</p><p>　　院（系、部）名 稱 ： 城市建設學院 </p><p>　　專 業(yè) 名 稱： 土木工程 </p><p>　　學 生 姓 名： ***

2、 </p><p>　　學 生 學 號： ********** </p><p>　　指 導 教 師： </p><p>　　2012 年 12 月 25 日</p><p>　　Across-wind loads and effects of super-tall

3、 buildings and</p><p>　　Structures</p><p><b>　　Abstract</b></p><p>　　Across-wind loads and effects have become increasingly important factors in the structural design of

4、 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 a

5、re very complicated. Although researchers have been focusing on the problem for over 30 years, the database of across-wind loads and effects and the computation methods of equivale</p><p>　　Introduction <

6、/p><p>　　With the development of science and technology, structures are becoming larger, longer, taller, and more sensitive to strong wind. Thus, wind engineering researchers are facing with more new challenges

7、, even problems they are currently unaware of. For example, the construction of super tall buildings is now prevalent around the world. The Chicago Sears Tower with a height of 443 m has kept the record of the world’s ta

8、llest building for 26 years now. Dozens of super-tall buildings with heights of</p><p>　　Davenport initially introduced stochastic concepts and methods into wind-resistant study on along-wind loads and effec

9、ts of buildings and other structures. Afterward, researchers developed related theories and methods, and the main research results have already been reflected in the load codes of some countries for the design of buildin

10、gs and structures. For modern super-tall buildings and structures, across- wind loads and effects may surpass along-wind ones. Although researchers have been focu</p><p>　　Therefore, studying across-wind vib

11、ration 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 cu

12、rrent paper thus reviews the research </p><p>　　situation of across-wind loads and effects of super-tall buildings and structures both at home and abroad. Then, the research results given by us are presented

13、. Finally, a case study of across-wind loads and effects of a typical super-tall structure is illustrated.</p><p>　　Mechanism of across-wind loads and effects </p><p>　　Previous researches focus

14、ed mainly on the mechanism of across-wind load. Kwok pointed out that across-wind excitation comes from wake, inflow turbulence, and wind-structure interaction effect, which could be recognized as aerodynamic damping. So

15、lari attributed the across-wind load to across-wind turbulence and wake excitations, considering wake as the main excitation. Islam et al. and Kareem claimed that across-wind responses are induced by lateral uniform pres

16、sure fluctuation due to separation </p><p>　　Across-wind aerodynamic force </p><p>　　As stated above, the across-wind aerodynamic force can be obtained basically through the following channels:

17、 identifying across-wind aerodynamic force from across-wind responses of an aero elastic building model in a wind tunnel; obtaining across-wind aerodynamic force through spatial integration of wind pressure on rigid mode

18、ls; obtaining generalized aerodynamic force directly from measuring base bending moment using high frequency force balance technique. </p><p>　　Identification of across-wind aerodynamic force from dynamic r

19、esponses of aero elastic building model. </p><p>　　This method employs across-wind dynamic responses of the aero elastic building model, combining the dynamic characteristics of the model to identify across

20、-wind aerodynamic force. Melbourne and Cheung performed aero elastic model wind tunnel tests on a series of circular, square, hexagon, polygon with eight angles, square with reentrant angles and fillets, and tall or cyli

21、ndrical structures with sections contracting along height. However, further studies showed that across-wind aerodynamic dampi</p><p>　　Wind pressure integration method. </p><p>　　Researchers ha

22、ve recommended wind pressure integration to obtain more accurately the across-wind aerodynamic forces on tall buildings. Islam et al . adopted this method to obtain across-wind aerodynamic forces on tall buildings and s

23、tructures. Cheng et al. experimentally studied across-wind aerodynamic forces of typical buildings under different wind field conditions and derived empirical formulas for the power spectrum density of the across-wind ae

24、rodynamic force reflecting the effects of turb</p><p>　　High frequency force balance technique.</p><p>　　Compared with the pressure measuring technique, high frequency force balance technique ha

25、s its unique advantage for obtaining total aerodynamic forces. The test and data analysis procedures are both very simple; hence, this technique is commonly used for selection studies on architectural appearance in the i

26、nitial design stage of super-tall buildings and structures. Currently, this technique is widely used for total wind loads acting on super-tall buildings and structures, and for dynamic respon</p><p>　　Kareem

27、 conducted an experimental study on across-wind aerodynamic forces on tall buildings with various section shapes in urban and suburban wind co research showed that for the buildings with , uncertainties of wind and struc

28、tural parameters have small effects on PSD of the across-wind aerodynamic force, and the correlation between the along-wind aerodynamic force and the across-wind aerodynamic force or the torsion moment is negligible, but

29、 there is a strong correlation between the across-wind</p><p>　　Across-wind aerodynamic damping </p><p>　　In 1978, Kareem performed an investigation on across-wind dynamic responses of tall bui

30、ldings based on both of the aero elastic model technique and the wind pressure integration method. He found out that the across-wind dynamic responses calculated with the across-wind aerodynamic forces obtained from the

31、wind pressure tests at a certain test wind velocity range were always smaller than those of the aero elastic model of the same building model. This important result made researchers realize the</p><p>　　Subs

32、equently, researchers carried out numerous studies on the problem and developed effective methods for identifying aerodynamic damping. The first kind of method obtains aerodynamic damping by comparing the dynamic respons

33、es computed based on the aerodynamic forces from rigid building model tests and those from aero elastic model tests. The second one separates aerodynamic damping force from the total aerodynamic force measured from aero

34、elastic building models or forced vibration building mod</p><p>　　Steckley initially developed a set of forced vibration devices for measuring total aerodynamic forces, including aerodynamic damping force an

35、d aerodynamic force. He measured the base bending moment of a tall building model, which was vibrated by a specially designed device. The aerodynamic force related to structure motion was separated from the total aerodyn

36、amic force, and then it was decomposed into aerodynamic stiff force and aerodynamic damping force to obtain aerodynamic damping. Vickery an</p><p>　　Identifying aerodynamic damping based on the stochastic vi

37、bration responses of aero elastic building models can be performed using appropriate system identification techniques, which include frequency domain methods, time domain methods, and frequency-time domain methods. Among

38、 these methods, the random decrement method, one of the time domain methods, is broadly adopted to identify the aerodynamic damping of tall buildings and structures. Jeary introduced the random decrement technique to ide

39、nt</p><p>　　Application to the codes </p><p>　　As stated above, although researchers have been focusing on across-wind loads on tall buildings for over 30 years now, the widely accepted databas

40、e of across-wind loads and computation methods of equivalent static wind loads have not been developed yet. Moreover, only a few countries have adopted related contents and provisions in their codes.</p><p>

41、　　Compared with the codes of other countries, the Architectural Association of Japan provides the best method for across-wind loads for structural design of tall buildings. Nevertheless, the formula for PSD of the across

42、-wind force in the code can only be applied to tall buildings with aspect ratios of less than six, which seems difficult to meet the actual needs. In addition, the method takes across-wind inertia load of fundamental mod

43、e as across-wind equivalent static wind load including backgro</p><p>　　. In the present load code for the design of building structures (GB50009-2001) of world, only a simple method for calculating vortex-i

44、nduced resonance of chimney-like tall structures with a circular section is provided, which is not applicable to the wind-resistant design for tall buildings and structures in general. In the design specification titled

45、“Specification for Steel Structure Design of Tall Buildings” , our related research results have been adopted. </p><p>　　Concluding remarks </p><p>　　With the continuing increase in the height

46、of buildings, across-wind loads and effects have become increasingly important factors for the structural design of super-tall buildings and structures. The current paper reviews researches on across-wind loads and effec

47、ts of super-tall buildings and structures, including the mechanism of across-wind loads and effects, across-wind aerodynamic forces, across-wind aerodynamic damping, and applications in the code. Consequently, some of ou

48、r research achiev</p><p>　　超高層建筑結(jié)構(gòu)橫向風荷載效應</p><p><b>　　摘要</b></p><p>　　隨著建筑高度的不斷增加，橫向風荷載效應已經(jīng)成為影響超高層建筑結(jié)構(gòu)設計越來越重要的因素。高層建筑結(jié)構(gòu)的橫向風荷載效應被認為由空氣湍流，搖擺以及空氣流體結(jié)構(gòu)相互作用所引起的。這些都是非常復雜的。盡管30

49、年來，研究人員一直關注這個問題，但橫向風荷載效應的數(shù)據(jù)庫以及等效靜力風荷載的計算方法還沒有被開發(fā)，大多數(shù)國家在荷載規(guī)范里還沒有相關的規(guī)定。對超高層建筑結(jié)構(gòu)的橫向風荷載效應的研究成果主要包括橫向風荷載的動力以及動力阻尼的測定，數(shù)據(jù)庫的開發(fā)和等效靜力風荷載的理論方法的等等。在本文中，我們首先審查目前國內(nèi)外關于超高層建筑結(jié)構(gòu)風荷載的影響的研究。然后我們在闡述我們的研究成果。最后，我們會列舉我們研究成果在超高層建筑結(jié)構(gòu)中應用的的案例。</

50、p><p><b>　　引言</b></p><p>　　隨著科技的發(fā)展，建筑物也越來越長、高、大，越來越對強風敏感。因此，風工程研究人員面臨著更多新的挑戰(zhàn)，甚至一些未知的問題。例如，超高層建筑現(xiàn)在在全世界普遍流行。高度為443米的芝加哥希爾斯塔保持了是世界上最高建筑物26年的記錄，現(xiàn)在還有幾十個超過400米的超高層建筑被建造。828米高的迪拜塔已經(jīng)建造完成。在發(fā)達國家，

51、甚至有人建議建造數(shù)千米的“空中城市”。隨著高度的增加，輕質(zhì)高強材料的使用，風荷載效應特別是具有低阻尼的超高層建筑橫向風動力響應將變得更加顯著。因此，強風荷載將成為設計安全的超高層建筑結(jié)構(gòu)中的一個重要的控制因素。</p><p>　　達文最初引入隨機的概念和方法應用發(fā)哦順風向荷載效應的建筑物和其他結(jié)構(gòu)的抗風研究。之后，研究人員完善了相關的理論和方法，并且主要的研究成果已經(jīng)反映在一些國家的結(jié)構(gòu)設計荷載規(guī)范里。對現(xiàn)代超

52、高層建筑結(jié)構(gòu)，橫風向風荷載的作用可能已經(jīng)超過順風向荷載效用。雖然研究人員已經(jīng)關注這個方向已經(jīng)30多年了，但能夠被廣泛接受的橫風向荷載數(shù)據(jù)庫以及等效靜力荷載的計算方法還沒有形成。只有少數(shù)國家在他們的荷載規(guī)范里有相關的內(nèi)容和規(guī)定。</p><p>　　因此，研究超高層建筑結(jié)構(gòu)橫風向風振和等效靜力荷載在超高層建筑設計領域內(nèi)具有重要的理論意義和實用價值。</p><p>　　橫風向荷載及作用機制&

53、lt;/p><p>　　過去的研究主要集中在橫風向荷載機制。橫風向荷載的激發(fā)主要由于被公認為空氣動力阻尼的尾流、空氣湍流以及風荷載耦合作用。索拉里認為橫風向荷載主要由于尾流的原因所引起?？ɡ锬仿暦Q橫風向的效應主要是由分離剪切層和尾流波動引起的橫向均勻壓力波動所引起的。目前，高層建筑橫風向荷載機制已被人為是流入湍流激發(fā)、尾流激發(fā)、以及氣動彈性影響。湍流以及尾流激勵一般是外部空氣動力，在本文章中，所涉及的統(tǒng)稱為空氣動力。

54、同時，氣體的彈性效應可以被認為是氣體動力阻尼。橫風向氣體動力不再像順向風一樣符合準穩(wěn)態(tài)假設。因此，橫向風荷載譜不能直接作為一個脈動風速譜。對不穩(wěn)定風壓力來說，風洞試驗技術是目前研究橫向風動力的主要技術。風洞試驗技術主要包括氣體彈性模型試驗、高頻力平衡試驗以及對多點壓力測量的剛性模型實驗技術。用橫風向外部動力，橫風向氣動阻尼，橫向風響應和建筑結(jié)構(gòu)等效靜力風荷載的數(shù)據(jù)可以對超高層建筑結(jié)構(gòu)進行計算。</p><p>&

55、lt;b>　　橫風向氣動力</b></p><p>　　如上所述，橫風向氣動力基本上可以通過以下途徑獲得：從氣動彈性模型在一個風洞的橫風向響應確定橫風向氣動力；通過剛性模型風壓空間一體化獲得橫向風動力；使用高頻測力天平技術測量基底彎矩來獲得廣義的氣動力。</p><p>　　從氣動彈性模型的動態(tài)響應確定橫風向氣動力。這種方法采用的是氣動彈性模型的橫風向風振響應，結(jié)合動態(tài)特

56、性的模型識別橫風向氣動力。墨爾本對對一系列圓形、方形、六角形、多邊形沿高度分布進行氣動彈性模型風洞試驗。然而進一步試驗表明您橫風向氣動阻力與氣動力混合在一起，使他難以準確地提取氣動阻尼力。因此，該方法很少使用。</p><p><b>　　風壓積分法</b></p><p>　　研究人員建議用風壓積分法獲取更準確的高層建筑橫風向氣動力。伊斯蘭等人采用這種方法得到橫風向

57、氣動力，陳等人研究了典型建筑結(jié)構(gòu)在不同風場條件橫風向氣動力。影響橫風向氣動力的因素主要有湍流強度、湍流尺度。湍流強度被發(fā)現(xiàn)擴大帶氣動力和降低峰值。然而,湍流強度被認為對總能量幾乎沒有影響。因此,研究人員在某種程度上已經(jīng)意識到了在風力條件定量規(guī)則的變化橫風氣動力。梁等人使用這種方法檢查了建筑物上的典型矩形邊界層風洞橫風向氣動力，從而提出高大的建筑物的經(jīng)驗公式和橫風向動態(tài)響應模型。結(jié)果表明, 橫風向湍流對于橫風向氣動力的貢獻比那些激勵要小的

58、多。基于大量的結(jié)果,導出橫風向湍流激勵和激發(fā)后的PSD計算公式。第一廣義的橫風向氣動力計算可以通過在剛性建筑模型整合壓力分布得到，這是該方法一個重要的優(yōu)越性。然而,考慮到在這類方法需要大量的大規(guī)模的結(jié)構(gòu)測壓，同步測量風壓是很難實現(xiàn)的。此外,對于建筑和結(jié)構(gòu)復雜的配置,準確的風壓分布和空氣動力難以使用這種方法。</p><p><b>　　高頻測力平衡技術</b></p><

59、p>　　與壓力測量技術相比，高頻力平衡技術對于得到總氣動力有其獨特的優(yōu)勢，檢測和數(shù)據(jù)分析過程都很簡單。因此這項技術通常應用于初期設計階段的建筑外觀的選擇。目前這項技術被廣泛應用于作用在超高層建筑結(jié)構(gòu)的全風荷載以及動力響應計算。高頻力平衡技術自從1970年已經(jīng)逐漸發(fā)展起來。賽馬可等人是第一批把此技術應用到模型測量的人。他們最初提出平衡模型系統(tǒng)應有一個比風力頻率更高的固有頻率。由常和達文發(fā)展的平衡技術標志著平衡設備的成熟。</p

60、><p>　　卡里姆進行了一項實驗研究。對于在城市和郊區(qū)具有不同截面形式的高層建筑的橫風向氣動力研究表明對于建筑物風的不確定以及結(jié)構(gòu)參數(shù)對橫風向空氣動力的設計有很小的影響并且順風向和橫風向氣動力或扭矩之間的聯(lián)系時微不足道的。但橫風向動力和扭矩之間的聯(lián)系是非常密切的。這個結(jié)論對于三維方向精確的風荷載模型是很重要的。特別是石和全等人做了一系列關于矩形建筑的邊率，建筑物橫截面形狀，建筑的面率的效應以及用五元平衡的高層建筑橫

61、風向動力設計的風域條件。事實上，基于大量的風隧道檢測結(jié)果典型高層建筑橫風向氣動力系數(shù)的公式已經(jīng)被我們建立了。</p><p><b>　　橫風向氣動阻尼</b></p><p>　　1978年卡里姆對基于氣動彈性模型技術和風壓積分法的高層建筑橫風向動力響應做了一次調(diào)查研究。他指出由在一定范圍內(nèi)風壓力測試獲得的橫風向氣動力計算而得到的橫風向風振響應總是比那些相同建筑模型

62、的氣動彈性模型要小。這個重要的研究成果使得研究人員認識到橫風向氣動負阻尼的存在。</p><p>　　后來，研究人員對這個問題進行了大量的研究并且找到了有效的方案來確定氣動阻尼。第一種方法是通過比較基于來自剛性模型試驗和氣動彈性模型試驗的氣動力所得到的到哪個臺響應。第二種方法是從由氣動彈性模型或強迫振動模型所得到的總氣動力中分離出氣動阻力。第三種方法是從氣動彈性模型分離氣動阻尼的的識別方法。此外，研究人員意識到風

63、因素的影響規(guī)律。這些因素包括結(jié)構(gòu)形狀、結(jié)構(gòu)動力參數(shù)、風條件等等?？ɡ锬返热耸堑谝慌岢鐾ㄟ^比較來確定氣動阻尼的方法。陳等人采用這種技術來研究橫風向效應和高層建筑結(jié)構(gòu)的動態(tài)阻尼并提出了一個氣動阻尼公式。</p><p>　　史迪克最初制造了一批測定總氣動力、氣動阻尼力與氣動力的強迫振動測量設備。他測量高層建筑模型基底彎矩是通過一個專門的設計裝置產(chǎn)生振動所產(chǎn)生的有關的氣動力從總氣動力脫離進而分解為氣動應力和氣動阻尼力

64、獲得氣動阻尼?？虏噲D對諧波振動建筑模型測量風壓獲得總氣動力。然后用類似史迪克的方法計算空氣阻尼。這種方法的優(yōu)點是真實的建筑特性并非必須被考慮到。這種方法更方便更實用，特別是在推廣實驗結(jié)果。這種方法的的主要缺點是它需要復雜的設備，尤其是直到現(xiàn)在多元耦合裝置是不可用的。</p><p>　　確定氣動阻尼的隨機振動響應的氣動彈性模型課采用適當?shù)南到y(tǒng)識別技術，其中包括頻域法，時域的方法以及時域頻域的方法。在這些方法中隨

65、機減量法、時域方法被廣泛采用以確定高層建筑的氣動阻尼。杰瑞介紹隨機減量法來識別結(jié)構(gòu)阻尼。馬克采用隨機減量法確定高層建筑順橫風向氣動阻尼。他們分析了影響建筑長寬比、邊比、氣動阻尼、結(jié)構(gòu)阻尼。田村等人用隨機減量技術確定超高層建筑氣動阻尼。全等人通過實驗確定在不同的風領域具有不同結(jié)構(gòu)中阻尼方形截面的橫風向氣動阻尼，并得出了一個經(jīng)驗公式。這些研究成果已通過相關的中國規(guī)范。秦和谷是第一個引入隨機空間識別方法于氣動參數(shù)的確認的研究人員。這些氣動參數(shù)

66、包括大跨度橋梁氣動剛度和阻尼。于隨機變量法相比，隨機空間識別方法具有更多的優(yōu)點。它能克服隨機變量法的弱噪音抵抗力和需要大量實驗數(shù)據(jù)的缺點。秦采用這種方法來確定高層建筑的氣動阻尼。</p><p><b>　　規(guī)范的實用性</b></p><p>　　如上所說，雖然研究者一直關注高層建筑風荷載超過30年了，但被廣泛接受的橫風向風荷載數(shù)據(jù)庫和計算方法，等效靜力風荷載尚未開

67、發(fā)。此外，只有少數(shù)國家采用相關的規(guī)定和代碼。于其他國家相比，日本建筑協(xié)會提供了計算高層建筑結(jié)構(gòu)橫風向荷載的最好方法。然而公式的橫風向代碼知適用于高層建筑高寬比小于六，這似乎很難滿足實際需要。而且此方法在這種方法里氣動阻尼沒有被考慮。</p><p>　　在目前的建筑結(jié)構(gòu)荷載規(guī)范只提供了一個簡單的方法來計算渦激共振的高聳結(jié)構(gòu)，而一般不適用于高層建筑結(jié)構(gòu)抗風設計。在題為“高層建筑鋼結(jié)構(gòu)設計詳細說明”里，我們的研究成果

68、已經(jīng)通過。</p><p><b>　　總結(jié)</b></p><p>　　隨著建筑高度不斷增加，橫風向荷載效應已經(jīng)成為超高層建筑結(jié)構(gòu)設計的重要因素。目前，對超高層建筑結(jié)構(gòu)橫風向荷載的研究主要包括橫風向風荷載的機制，橫風向氣動力、氣動阻尼和在規(guī)范中的應用。因此我們的一些研究成果主要有典型建筑結(jié)構(gòu)的橫風向力，氣動阻尼以及在中國規(guī)范的應用。最后介紹了典型的案例，在這個案例中