建筑專業(yè)畢業(yè)設計外文翻譯---張弦梁結(jié)構(gòu)的探討

1、<p><b>　　附錄A</b></p><p><b>　　張弦梁結(jié)構(gòu)的探討</b></p><p>　　摘要：本文就張弦梁結(jié)構(gòu)中的相關(guān)問題作一些說明，以及張弦梁結(jié)構(gòu)研究的現(xiàn)狀和需要以后研究的問題。本文還討論張弦梁結(jié)構(gòu)的影響因素，以及目前找形分析的方法。 </p><p>　　關(guān)鍵詞：張弦梁結(jié)構(gòu) 找形 預應力

2、 穩(wěn)定問題  </p><p><b>　　0 引言</b></p><p>　　張弦梁結(jié)構(gòu)最早是由日本大學M.Saitoh教授提出，是一種區(qū)別于傳統(tǒng)結(jié)構(gòu)的新型雜交屋蓋體系。張弦梁結(jié)構(gòu)是一種由剛性構(gòu)件上弦、柔性拉索、中間連以撐桿形成的混合結(jié)構(gòu)體系，其結(jié)構(gòu)組成是一種新型自平衡體系，是一種大跨度預應力空間結(jié)構(gòu)體系，也是混合結(jié)構(gòu)體系發(fā)展中的一個比較成功的創(chuàng)造。張弦

3、梁結(jié)構(gòu)體系簡單、受力明確、結(jié)構(gòu)形式多樣、充分發(fā)揮了剛?cè)醿煞N材料的優(yōu)勢，并且制造、運輸、施工簡捷方便，因此具有良好的應用前景。　　本文就張弦梁結(jié)構(gòu)的分類，受力機理，張弦梁結(jié)構(gòu)的找形分析，用有限元分析總結(jié)了撐桿數(shù)目、垂跨比、高跨比、拱的慣性矩、弦的預應力等對張弦梁結(jié)構(gòu)的受力性能的影響，以及結(jié)構(gòu)的穩(wěn)定性分析。</p><p>　　1、張弦梁結(jié)構(gòu)的受力機理和分類</p><p>　　1.1、張弦

4、梁結(jié)構(gòu)的受力機理</p><p>　　目前，普遍認為張弦梁結(jié)構(gòu)的受力機理為通過在下弦拉索中施加預應力使上弦壓彎構(gòu)件產(chǎn)生反撓度，結(jié)構(gòu)在荷載作用下的最終撓度得以減少，而撐桿對上弦的壓彎構(gòu)件提供彈性支撐，改善結(jié)構(gòu)的受力性能。一般上弦的壓彎構(gòu)件采用拱梁或桁架拱，在荷載作用下拱的水平推力由下弦的抗拉構(gòu)件承受，減輕拱對支座產(chǎn)生的負擔，減少滑動支座的水平位移。由此可見，張弦梁結(jié)構(gòu)可充分發(fā)揮高強索的強抗拉性能改善整體結(jié)構(gòu)受力性能

5、，使壓彎構(gòu)件和抗拉構(gòu)件取長補短，協(xié)同工作，達到自平衡，充分發(fā)揮了每種結(jié)構(gòu)材料的作用。　　所以，張弦梁結(jié)構(gòu)在充分發(fā)揮索的受拉性能的同時，由于具有抗壓抗彎能力的桁架或拱而使體系的剛度和穩(wěn)定性大為加強。并且由于張弦梁結(jié)構(gòu)是一種自平衡體系，使得支撐結(jié)構(gòu)的受力大為減少。如果在施工過程中適當?shù)姆旨壥┘宇A拉力和分級加載，將有可能使得張弦梁結(jié)構(gòu)對支撐結(jié)構(gòu)的作用力減少的最小限度。</p><p>　　1.2、張弦梁結(jié)構(gòu)的分類&l

6、t;/p><p>　　張弦梁結(jié)構(gòu)按受力特點可以分為平面張弦梁結(jié)構(gòu)和空間張弦梁結(jié)構(gòu)?！　∑矫鎻埾伊航Y(jié)構(gòu)是指其結(jié)構(gòu)構(gòu)件位于同一平面內(nèi)，且以平面內(nèi)受力為主的張弦梁結(jié)構(gòu)。平面張弦梁結(jié)構(gòu)根據(jù)上弦構(gòu)件的形狀可以分為三種基本形式：直線型張弦梁、拱形張弦梁、人字型張弦梁結(jié)構(gòu)。　　直梁型張弦梁結(jié)構(gòu)主要用于樓板結(jié)構(gòu)和小坡度屋面結(jié)構(gòu)，拱形張弦梁結(jié)構(gòu)充分發(fā)揮了上弦拱得受力優(yōu)勢適用于大跨度的屋蓋結(jié)構(gòu)，人字型張弦梁結(jié)構(gòu)適用于跨度較小的雙坡屋

7、蓋結(jié)構(gòu)。</p><p>　　空間張弦梁結(jié)構(gòu)是以平面張弦梁結(jié)構(gòu)為基本組成單元，通過不同形式的空間布置所形成的張弦梁結(jié)構(gòu)。空間張弦梁結(jié)構(gòu)主要有單向張弦梁結(jié)構(gòu)、雙向張弦梁結(jié)構(gòu)、多向張弦梁結(jié)構(gòu)、輻射式張弦梁結(jié)構(gòu)?！　蜗驈埾伊航Y(jié)構(gòu)由于設置了縱向支撐索形成的空間受力體系，保證了平面外的穩(wěn)定性，適用于矩形平面的屋蓋結(jié)構(gòu)。雙向張弦梁結(jié)構(gòu)由于交叉平面張弦梁相互提供彈性支撐，形成了縱橫向的空間受力體系，該結(jié)構(gòu)適用于矩形、圓形、

8、橢圓形等多種平面屋蓋結(jié)構(gòu)。多向張弦梁結(jié)構(gòu)是平面張弦梁結(jié)構(gòu)沿多個方向交叉布置而成的空間受力體系，該結(jié)構(gòu)形式適用于圓形和多邊形平面的屋蓋結(jié)構(gòu)。輻射式張弦梁結(jié)構(gòu)是由中央按輻射狀放置上弦梁，梁下設置撐桿用環(huán)向索而連接形成的空間受力體系，適用于圓形平面或橢圓形平面的屋蓋結(jié)構(gòu)。</p><p>　　2、張弦梁結(jié)構(gòu)的找形分析</p><p>　　2.1 張弦梁結(jié)構(gòu)的形態(tài)定義</p><

9、;p>　　張弦梁結(jié)構(gòu)象懸索結(jié)構(gòu)等柔性結(jié)構(gòu)一樣，根據(jù)張弦梁結(jié)構(gòu)的加工、施工、及受力特點。通常也將其結(jié)構(gòu)形態(tài)定義為零狀態(tài)、初始態(tài)和荷載態(tài)?！　×銧顟B(tài)，是拉索張拉前的狀態(tài)，實際上是構(gòu)件加工和放樣形態(tài)，通常也叫結(jié)構(gòu)放樣態(tài)?！　〕跏紤B(tài)，是拉索張拉完畢后，結(jié)構(gòu)安裝就位的形態(tài)，通常也叫預應力狀態(tài)。初始態(tài)是建筑施工圖中明確的結(jié)構(gòu)外形。（包括在自重作用下）　　荷載態(tài)，是外荷載作用在初始態(tài)結(jié)構(gòu)上發(fā)生變形后大平衡態(tài)?！　　∪绻麖埾伊航Y(jié)構(gòu)的上弦構(gòu)

10、件按照初始形態(tài)給定的幾何參數(shù)進行加工放樣，那么在張拉拉索時，由于上弦構(gòu)件剛度較弱，拉索的張拉勢必會引導撐桿使上弦構(gòu)件產(chǎn)生向上的變形，當張拉完畢后，結(jié)構(gòu)上弦構(gòu)件的形狀將偏離初始形態(tài)，從而不滿足建筑設計的要求。因此，張弦梁結(jié)構(gòu)上弦構(gòu)件的加工放樣通常要考慮張拉產(chǎn)生的變形影響，這也是張弦梁結(jié)構(gòu)需要進行形態(tài)定義的原因。</p><p>　　2.2 張弦梁結(jié)構(gòu)找形分析</p><p>　　目前有關(guān)文獻

11、中找形的方法不外乎有張其林提出的逆迭代法、文獻中改進的逆迭代法。</p><p>　　I.逆迭代法的簡介　　逆迭代法實際上是一種非常自然的思路：既然設計藍圖上的張弦梁幾何尺寸是初狀態(tài)(預應力張拉完畢時結(jié)構(gòu)的狀態(tài))的尺寸，那么就可以以此初狀態(tài)尺寸為近似零狀態(tài)尺寸建立有限元模型，然后對其施加預應力(預應力值按設計要求)進行張拉，得到近似初狀態(tài)。然后將此近似初狀態(tài)的幾何尺寸與設計圖中真正的初狀態(tài)的幾何尺寸的差值反向增

12、加到原有限元模型的節(jié)點坐標上，作為近似初狀態(tài)重新建模，并再次進行張拉，如此循環(huán)迭代，直到近似初狀態(tài)與初狀態(tài)的坐標差值足夠小，即可視此近似初狀態(tài)為初狀態(tài)，而由之張拉而來的近似零狀態(tài)為要求的零狀態(tài)。如此既可得到零狀態(tài)幾何尺寸(施工人員據(jù)此放樣)，又可得到初狀態(tài)的內(nèi)力、應力分布，從而完成找形工作。實踐證明，只需進行次數(shù)不多的迭代，就可達到足夠的找形計算精度。II.改進的逆迭代法　　上面提到的逆迭代法是將端部索段斷開，，釋放該處屋架上下弦的

13、水平約束，并將該索段的預拉力的水平分量作為外力分別反向作用在屋架上下弦端部，進而一步步逆迭代計算。這種處理方法固然可以求出零狀態(tài)的幾何參數(shù)和初始態(tài)預應力分布，但是如果要在此基礎上繼續(xù)進行荷載態(tài)的分析，則舉步維艱。因為索切斷之后的結(jié)</p><p>　　假定圖紙給定的結(jié)構(gòu)初始態(tài)坐標表示為{X  Y Z} ，經(jīng)過第k次迭代后所得的零狀態(tài)幾何坐標為{X Y Z} 初始態(tài)坐標為{X Y Z} ，位移為{U} 。

14、</p><p>　　(1)首先假設當前的幾何即為零狀態(tài)幾何，即令{X Y Z}＝{X  Y Z}。</p><p>　　(2)在某(些)索段加上初應變(預估)，對幾何為{X Y Z} 的結(jié)構(gòu)計算得位移{U} ，k＝1</p><p>　　(3)計算{X Y Z}＝{X Y Z}+ {U}，令△＝{X  Y Z} 一{X Y Z} 。</p

15、><p>　　(4)判別△是否滿足給定的精度。若滿足，則{X  Y Z}即為所求的零狀態(tài)幾何坐標；若不滿足，則令{X Y Z} ＝{X Y Z} + △，轉(zhuǎn)第二步，并令       k＝k+ 1。</p><p>　　(5) 由以上步驟得出零狀態(tài)的幾何參數(shù)后，將初應變值賦予該索段求出平衡后所得到的狀態(tài)即為初始態(tài)預應力分布。此

16、時，應當檢驗該索段的內(nèi)力值是否為預定值，如果不是，則應當調(diào)整初應變值從步驟(2)重新計算。</p><p>　　3、單榀張弦梁結(jié)構(gòu)性能各影響因素分析</p><p>　　3.1 對單榀張弦梁結(jié)構(gòu)性能各影響因素分析的研究現(xiàn)狀</p><p>　　文獻[4]通過對撐桿數(shù)目、垂跨比、高跨比、梁的截面特性和弦的預應力等參數(shù)對單棍張弦梁結(jié)構(gòu)靜力性能的影響進行分析，得出以下結(jié)論

17、:(1)、撐桿數(shù)目：通過撐桿連接拱和弦的張弦梁結(jié)構(gòu)，受力合理。但是撐桿數(shù)目的增加并不能改善結(jié)構(gòu)的受力性能，文獻[4]以一跨度為22.4m的單榻張弦梁為例進行分析，認為該情況下?lián)螚U數(shù)超過3個后，受力性能改善效果不再明顯，所以撐桿數(shù)目以3個為益。(2)、垂跨比或高跨比的影響： 垂跨比是下弦索的垂度和結(jié)構(gòu)跨度的比值價/L),高跨比是上弦梁的矢高和結(jié)構(gòu)跨度的比值切IL)。隨著垂跨比或高跨比的增大，除剪力外，其它內(nèi)力如梁的彎矩和軸力以及索的最

18、大應力都減小，同時結(jié)構(gòu)的變形也減小，但半跨荷載下的變形幅度小于全跨荷載下的變形幅度，因此，當垂跨比達到某個特定值后，位移反應的不利荷載由全跨荷載轉(zhuǎn)為半跨荷載。(3)、上弦梁的慣性矩的影響：隨著上弦梁的慣性矩的增大，全跨荷載下的變形兒乎沒有變化，但半跨荷裁下的變形顯著減小，并且全跨荷載下的最大正應力和半跨荷載下的梁的正應力也減小，所以通過增大梁的慣性矩，來提高半跨荷載下的剛度及結(jié)構(gòu)受力性能是有益的。(4)、梁截面面積的影響：隨著梁&l

19、t;/p><p>　　3.2  對單榀張弦梁結(jié)構(gòu)各因素影響分析的新認識</p><p>　　鑒于以上文獻分析，本人覺得還有如下方面影響因素分析：垂跨比＋高跨比、撐桿的布置方式（如斜向布置、豎斜向布置），還有考慮撐桿和拉索的接觸分析。</p><p><b>　　4、結(jié)論與展望</b></p><p>　　本文就張弦

20、梁結(jié)構(gòu)的受力機理和分類作了一定的說明，施工中的找形問題的方法作了介紹，還有介紹了目前文獻中有關(guān)對張弦梁結(jié)構(gòu)的影響因素及本人覺得還應該考慮的一些因素。　　在目前的研究中，還應該考慮的一些問題：(1)、索單元的數(shù)值模型問題。采用桿單元是不能精確描述索在低應力水平下的狀態(tài)，選擇合適的索單元來進行數(shù)值分析是值得討論的問題。(2)、對非線性有限元的收斂速度需要做深入的研究。在結(jié)構(gòu)計算中經(jīng)常會遇到用非線性有限元計算不收斂的問題。(3)、對于

21、大跨度張弦梁結(jié)構(gòu)的風致振動、結(jié)構(gòu)的振動特性以及振動控制是目前急需研究的問題，包括風場和風速的模擬、隨機振動和藕合問題等(4)、本文討論的基本上是單榀平面張弦梁結(jié)構(gòu)，此外，對于空間張弦梁結(jié)構(gòu)比如空間雙向、多向張弦梁結(jié)構(gòu)、輻射式張弦梁結(jié)構(gòu)其受力性能，有待更進一步的分析和研究。(5)、現(xiàn)在的分析都是基于線彈性材料下的幾何非線性分析，對于強震等較大荷載作用下的彈塑性分析，有待更進一步的研究。</p><p><

22、b>　　附錄Ｂ</b></p><p>　　Tring of beam structure</p><p>　　Abstract : This article beam string structure of the relevant issues to make some explanations, and the beam string structure of th

23、e status and needs of future research. This paper also discusses beam string of factors, and the current form-finding methods of analysis.</p><p>　　Keywords : String beam structure for stability prestressed.

24、</p><p>　　0 Introduction </p><p>　　String beam structure is the first by the Japanese University Professor M. Saitoh, is a distinguished from the traditional structure of the new hybrid roof sys

25、tems. String beam structure is a component wind from the rigid, flexible cable, in the middle pole connected to the formation of mixed structural system, its structure is a new self-balancing system is a large-span prest

26、ressed structure. Mixed structure is the development of a more successful creations. String simple beam structure, a clea</p><p>　　In this paper, beam string structure of the classification, the mechanism of

27、 power, beam string structure of the form-finding analysis, Finite element analysis summed up the pole number of vertical cross-ratio, high-ratio, the arch moment of inertia, String of the prestressed concrete beam strin

28、g structure, the mechanical properties of impact and structural stability analysis.</p><p>　　1, beam string to the stress mechanism and classification of .</p><p>　　1, beam string structure of t

29、he mechanism of force.</p><p>　　Currently, generally considered beam string structure of the force through the mechanism of the last quarter of prestressed cables were imposed so that wind columns have anti-

30、deflection , the load structure of the final deflection can be reduced, and pole bending to the wind to provide flexibility to support component, improve the structure of mechanical performance. General tighten the use o

31、f columns or beams arch truss arch, under load arch thrust by the level of the last quarter tensile compo</p><p>　　Therefore, the beam string giving full play to the structure of the cable tension capabiliti

32、es, but Because of the bending resistance of truss or arch makes the system stiffness and stability has been significantly strengthened. As the string and beam structure is a self-balancing system, support structure make

33、s the force greatly reduced. If in the course of construction to impose proper grading and classification of pre-tension loading, will be possible to make beam string structure of the supp</p><p>　　1.2, beam

34、 string structure of the classification </p><p>　　String beam structure by force characteristics can be divided into planar beam string structure and spatial beam string structure.</p><p>　　Plan

35、e beam string structure is its structural component in the same plane and the plane to force the main beam string structure. Plane beam string structure based on the shapes of wind component can be divided into three bas

36、ic forms : linear beam string, the string of arched beams, Text string people beam structure (figure 2). </p><p>　　Straight beam-beam string structure for the main floor structure and the small slope roof st

37、ructure, String arched beam into full play the wind arch subject to applicable to the advantage of large-span roof structure, Text string people beam structure in the span of two smaller slope roof structure.</p>

38、<p>　　String space beam structure is planar beam string structure of the basic components, through different forms of spatial layout formed by String beam structure. Space beam string structure mainly unidirectional

39、 beam string structure, a two-way beam string structure, multi-beam string structure, String radiation-beam structure. </p><p>　　Unidirectional beam string structure Since the creation of a support cable ve

40、rtical space formed by the edge of the system, ensuring the stability of the plane outside, applied to the rectangular planar roof structure. Bidirectional beam string planar structure due to cross-beam string provide fl

41、exibility to support each other, forming a vertical and horizontal space force system, The structure applicable to the rectangular, circular, elliptical and other planar roof structure. Multi-beam string</p><p

42、>　　2, beam string structure of the form-findi</p><p>　　2.1 beam string structure definition of the form </p><p>　　String beam suspension structure as flexible structure, under String beam pro

43、cessing, construction, and mechanical characteristics. Usually its structure and morphology definition of a state of zero, the initial state and loading state.</p><p>　　Zero state is tensioned cables before

44、the state is actually processing and lofting component form, usually called lofting state structure.</p><p>　　Initial state is tensioned cables after installation of the structure in place in the state, usua

45、lly called prestressed state. Initial state of construction plans is clearly the structural shape. (Including under the weight)</p><p>　　Load state, the outer load in the initial state structural deformation

46、 occurred after the big equilibrium. </p><p>　　If the beam string structure of the wind component to the form in accordance with the initial set of geometric parameters for processing Lofting, Zhang Revised

47、then, because of weaker wind component stiffness, The tensioning cable is bound to guide the pole so that wind upward components produced the deformation, when the tension has been completed, Structure wind component wil

48、l depart from the shape of the initial form, thereby not satisfied architectural design requirements. Therefore, the bea</p><p>　　2.2 beam string structure form</p><p>　　At present the literatur

49、e to find a method gather there are Zhang Lin put the inverse iteration, literature improved inverse iteration.</p><p>　　I. inverse iteration method was introduced. </p><p>　　Inverse iteration i

50、s in fact a very natural idea : Since the design blueprint for the beam string geometry of the early state (pre-stressed tensioned structure of the finished state) the size, it can be the beginning of this approximate si

51、ze of the state of the state is the size of finite element model, Then the tendons (prestressed value according to design requirements) tensioned, the approximate initial state. Then save the state early approximation of

52、 the geometric dimensions and layout of t</p><p>　　II. Improved inverse iteration </p><p>　　The above-mentioned inverse iteration method is to end cable disconnected, and the release of the depa

53、rtment from top to bottom chord of the roof truss level constraints, The cable will of the Pretension of the level of external components as were reverse role in next roof truss chord end, then gradually reverse an itera

54、tive calculation. While this approach can be used to calculate the zero state geometric parameters and initial shapes. But if it is to continue on this basis for the analysis of </p><p>　　Improved inverse it

55、eration, instead of having cable tensioned to achieve, but REQUEST to put some of the size of the initial strain. it deformation in the coordination of the internal force cable to a predetermined value. Such changes can

56、be made to study issues on the basis of continuous bear outside under load analysis. Thus compensate for the past prestressed beam string structure of the mechanical properties failed to take into account the changing st

57、ate of defects.</p><p>　　Specific iterative process as follows : </p><p>　　Drawings to assume that the initial structure of the state coordinates (X Y Z) After k-th iteration after the zero stat

58、e geometric coordinates () X Y Z coordinates for the initial state (X Y Z) displacement (U).</p><p>　　First, assume that the current state of geometry that is zero geometry, and even if the (X) = Y Z X Y Z (

59、). </p><p>　　a certain (s) of the cable with the early response (estimates), right geometry - (X Y Z) structure calculated displacement (U), k = 1 </p><p>　　Calculations (X) = Y Z X Y Z (+) (U),

60、 △ X = (1) Y Z X Y Z (). </p><p>　　whether the discriminant △ to meet the precision. If satisfied, then () X Y Z represents zero for the state of geometric coordinates; If not satisfied, which makes (X) = Y

61、Z X Y Z (+) △, to the second step, and so k = k + 1. </p><p>　　derived from the above steps is the state of geometric parameters, will be given early strain of the cable sought after balance the state shall

62、be the initial shapes. At this point, should examine the cable Nalizhi of whether the predetermined value, if not, it should be adjusted from the initial strain steps (2) re-calculated. </p><p>　　3, single l

63、oad beam string structural performance analysis of the impact of factors </p><p>　　3.1 pairs of single load beam string structure factors affecting the performance analysis of the status quo </p><

64、p>　　The literature [4] by the number of pole pairs, vertical cross-ratio, high-ratio, the beam characteristics of prestressed Polyphonic parameters of single-string stick beam static properties of the analysis, come t

65、o the following conclusions :</p><p>　　(1), the number of pole : Pole arch connecting string chords beam structure, reasonable force. However, the increase in the number of pole does not improve the structur

66、e, the mechanical properties, the literature [4] in a span of a single fallen 22.4m string beam analysis that the number of pole after more than three, by the effect of behavior will not improve significantly, the pole n

67、umber to three for benefits.</p><p>　　(2), vertical cross-over or a high cross-over effects : vertical cross-over is the last quarter of the cable sag and span the ratio of price / L), There are high-wind ve

68、ctor high beams span the structure and the ratio of shear IL). With vertical cross-over or a high-ratio increase, in addition to shear, Other internal forces such as the beam moments and axial forces, as well as the larg

69、est cable stress are reduced, while the deformation is also decreased. But a half-load of the whole is less tha</p><p>　　(3), the moment of inertia of the beam wind effects : With the wind of the moment of i

70、nertia of the beam increases, full-load deformation infants between no change, but the half-a Conference where the deformation decreased significantly, full-load and the maximum stress load and half-beams under the stres

71、s decreases. Therefore, passage of the beam increased moment of inertia to enhance cross-half load and stiffness of the structural behavior is useful.</p><p>　　(4), the beam area of impact : With the beam si

72、ze increases, in addition to the beam have reduced stress, Other internal forces and deformation almost no changes, increases in the beam area, a force of the performance improvement is not obvious. </p><p>

73、　　(5), the last quarter of prestressed REQUEST : The impact of cable with the last quarter of prestressed increasing deformation significantly reduced, Arch stress also tend to decrease, but not obvious, the reason the p

74、restressed major help reduce the deformation.</p><p>　　(6), the last quarter of the area REQUEST : The impact of cable with last quarter the size of the increase, the deformation of the internal forces and S

75、olana significantly reduced, Beam stress also tend to decrease, but to a lesser extent, simply increasing the size of string, can increase stiffness and But the string of material strength to full use.</p><p&g

76、t;　　(7), beam type of impact : beam using H-section steel tube sections than from the mechanical point of view, more economical and reasonable.</p><p>　　(8), beam string structure size of the building should

77、 be allowed under the conditions of the greatest possible use of the vertical span; high-value ratio of in-plane to consider the role of wind in size; choosing the appropriate size Polyphonic beam, the area Leung made th

78、e greatest stress is the greatest stress Polyphonic simultaneously achieve limit state materials, String of exerting certain prestressed to enhance stiffness.</p><p>　　Literature [5] in the single load beam

79、string of parameters on the basis of the analysis, that the literature [16] Most of the content more accurately reflect the single load beam string structure of the static properties, However, some of the data reflecting

80、 the trend and unreasonable, and made some new understanding and conclusions. </p><p>　　(1), vertical cross-over or a high cross-over effects : literature [5] that, as vertical cross-over or a high-ratio inc

81、rease, Beam is not the moment but decreased significantly increased and therefore should not be unlimited increases vertical cross-over and high-Span.</p><p>　　(2), the string of prestressed : literature [4]

82、 that, with the last quarter of prestressed cable increases, deformation significantly reduced, and the literature [5] The analysis shows that the increase of prestressed structural deformation of almost negligible, even

83、 slightly affected; on the right prestressed beam string structure of the internal forces, literature [5] that the increase of prestressed structure will lead to internal forces of all items have increased correspondingl

84、y. For the ma</p><p>　　3.2 pairs of single load beam string structure analysis of the factors affecting the new understanding </p><p>　　Given the above analysis of the literature, I think there

85、are implications factors : vertical cross-than + high-ratio, pole of the layout (eg diagonal layout, vertical diagonal layout), and consider the cable pole and contact analysis.</p><p>　　4, conclusions and P

86、rospects </p><p>　　In this paper, beam string structure of the force mechanism and classification of certain note, Construction of the form-finding methods, There on the current literature on the right beam

87、string structure of the factors and I think that should also consider a number of factors. </p><p>　　In the current study, we should also consider some of the problems : </p><p>　　(1), cable ele

88、ment numerical model of the problem. Rod module used is not accurate to describe cable in low stress level in the state, choice of cable element to the numerical analysis is worthy of discussion.</p><p>　　(2

89、), the nonlinear finite element convergence needs to be done in-depth research. Calculation of the structure often encounter nonlinear finite element calculation of convergence problems.</p><p>　　(3), for th

90、e long-span beam string of wind-induced vibration, the vibration characteristics and vibration control is an urgent problem, including wind and wind speed simulation, Random vibration coupling problems and</p><

91、;p>　　(4), discussed in this paper are basically single load beam string planar structure, in addition, For space beam string structures such as two-way space, multi-beam string structure, the radiation-beam string str

92、ucture of its mechanical behavior, pending further analysis and research.</p><p>　　(5), the present analysis is based on linear elastic material under the geometric nonlinear analysis, For larger earthquake