土建畢業(yè)設(shè)計外文翻譯---一個未完工的二層預(yù)制混凝土結(jié)構(gòu)物的抗震測試

1、<p>　　Tests on a Half-Scale Two-Story Seismic-Resisting Precast Concrete Building</p><p>　　This paper describes experimental studies on the seismic behavior and design of precast concrete buildings. A h

2、alf-scale two-story precast concrete building incorporating a dual system and representing a parking structure in Mexico City was investigated. The structure was tested up to failure in a laboratory under simulated seism

3、ic loading. In some of the beam-to-column joints, the bottom longitudinal bars of the beam were purposely undeveloped due to dimensional constraints.</p><p>　　Emphasis is given in the study on the evaluation

4、 of the observed global behavior of the test structure. This behavior showed that the walls of the test structure controlled the force path mechanism and significantly reduced the lateral deformation demands in the preca

5、st frames. Seismic design criteria and code implications for precast concrete structures resulting from this research are discussed. </p><p>　　The end result of this research is that a better understanding o

6、f the structural behavior of this type of building has been gained results of simulated seismic load tests of a two story precast concrete building constructed with precast concrete elements that are used in Mexico are d

7、escribed herein. The structural system chosen in the test structure is the so called dual type, defined as the combination of structural walls and beam-to-column frames. Connections between precast beams and columns <

8、/p><p>　　In most precast concrete frames such as those shown in Fig, 1, longitudinal beam bottom bars are not fully developed due to constraints imposed by the dimensions of file columns in beam-to-column joint

9、s. In an effort to overcome this deficiency, and as described later, some practicing engineers in Mexico design these joints by providing hoops around the hooks of that reinforcement in order to achieve its required cont

10、inuity. However, this practice is not covered in the ACI Building Code (ACI318-</p><p>　　The objectives of this research were Io evaluate the observed behavior of a precast concrete structures in the laborat

11、ory and to propose the use of precast structural elements or precast structures with both an acceptable level of expected seismic performance and appealing features from the viewpoint of construction Emphasis is given in

12、 this paper on the global behavior of the test structure. In the second part of this research which gill be presented in a companion paper, the observed behavior </p><p>　　Structural and non structural damag

13、es observed in buildings during past earthquakes throughout the world have shown the importance of controlling lateral displacement in structures to reduce building damage during earth- quakes. It is also relevant to men

14、tion that there are several cases of structures in moderate earthquakes in which the observed damage in non-structural elements in buildings was considerable even though the structural elements showed little or no damage

15、. This behavior is also r</p><p>　　To minimize seismic damage during earthquakes, the above discussion suggests the convenience of using a structural system capable of controlling lateral displacements in st

16、ructures. A solution of this type is the so-called dual system. Studies by Paulay and Priestley4 on the seismic response of dual systems have shown that the presence of walls reduce the dynamic moment demands in structur

17、al elements in the frame subsystem. Also in conjunction with shake table tests conducted on a cast-in-place </p><p>　　DUCTILITY DEMAND IN DUAL SYSTEMS</p><p>　　In order to develop a base for a l

18、ater analysis of the observed seismic response of the test structure studied in this project a simple analytical model is used to evaluate the main features of ductility demands in dual systems. </p><p>　　Fi

19、g 2 shows the results of a simple approach to analyze the lateral load response iii a dual system. The lateral load has been normalized in such a manner that the combination of maximum lateral resistance in both subsyste

20、rn i.e. walls and frames--leads to a lateral resistance of the global system equal to unity b is also assumed that both subsystems have the same maximum lateral resistance. In the first case (Fig 2a), it is assumed that

21、the wall and frame subsystems have global displacement duc</p><p>　　As shown in Fig 2, the lateral deformation compatibility of the combined system is controlled by the lateral deformation capacity of the wa

22、ll subsystem. In the first case Fig 2ak an elastic-plastic envelope for the lateral global response of the dual system is assumed, and the corresponding displacement ductility (u) is equal to 33.For the second case (Fig.

23、 2b) with an elastic behavior of the frame subsystem, this ductility is equal to 25. </p><p>　　These simple examples illustrate that in the analyzed cases, due to the higher flexibility in the frame subsyste

24、ms as compared to those of the wall subsystern, in a dual system, the ductility demands in the frame subsystem result in smaller ductility values than those of the wall subsystem. This analytical finding was verified in

25、this study from the experimental studies conducted on the test structure. This verification is later discussed in the paper It is of interest to note that results of th</p><p>　　The test structure used in th

26、is investigation is a two-story precast concrete building, representative of a low-rise parking structure located in the highest seismic zone of Mexico City. The prototype was constructed at one-half scale. For the sake

27、of simplicity, ramps required in a parking structure have not been considered in the selected prototype structure. Their use, requiring large openings in the floor system, would have required a very complex model of the

28、floor system for both linear an</p><p>　　A detailed description of the dimensions, materials, design procedures, and construction of the test structure can be found elsewhere.6 A summary of this information

29、is given below. </p><p>　　The dimensions and some characteristics of the test structure are shown in Fig. 3. The longitudinal and transverse are shown in Fig3a. Also, the exterior (longitudinal) frame contai

30、ning the wall (Column Lines 1 and 3) are termed the lateral frame (see Fig, 3b), and the internal (longitudinal) frame with the single tee (Column Line 2) are termed the central frame. </p><p>　　Doable tees

31、spanning in the longitudinal direction are supported by L-shaped precast beams in the transverse direction as shown in Fig3a. The structure uses precast frames and precast structural walls, the latter elements functionin

32、g as the main lateral load resisting system. Fig. 4 shows an early phase of the construction of the test structure. As can be seen, the "windows'' in the columns and walls are left in these elements for a la

33、ter assemblage with the precast beams.</p><p>　　The unfastened design base shear required by the Mexico City Building Code (MCBC, 1993)2 is 0.2WT, where WT is the total weight of the prototype structure, ass

34、uming a dead load of 5,15 KPa (108 psi) and a live load of 0.98 KPa (20.5 psi). The prototype structure was designed using procedures of elastic analyses and proportioning requirements of the MCBC, In these analyses, the

35、 gross moment of inertia of the members in the structure was considered and rigid offsets (distances from the joints to t</p><p>　　Results from these analyses indicated that the structural walls in the test

36、structure would take about 65 percent of the design lateral loads. A review of the nominal lateral resistance of the structure using the MCBC procedures showed that this resisting force was about 1.3 times the required c

37、ode lateral resistance (0,2Wr), This is one of several factors, later discussed, that contributed to the over-strength of the structure.</p><p>　　The longitudinal reinforcement in all the structural elements

38、 of the test structore was deformed bars from Grade 420 steel. Table 1 lists the concrete compressive cylinder strengths for different members of the prototype structure. Fig. 5 shows typical reinforcing details for prec

39、ast beams spanning in the direction of the applied lateral load (see Fig. 3). </p><p>　　Figs. 6 and 7 show reinforcing details for the columns, and for the structural wails and their foundation, respectively

40、. It should be mentioned that the test structure was designed with the requirements for moderately ductile structures specified by the MCBC. According to these provisions, the test structure did not require special struc

41、tural walls with boundary elements such as those specified in Chapter 21 of AC1 318 02.</p><p>　　The precast two-story columns were connected to the precast foundation by unthreading them in a grouted socket

42、 type connection. The reinforcing details of the foundation, as well as its design procedure and behavior in the test structure are discussed in the companion paper? Tae beam-to-cadmium joints in file test structure were

43、 cast-in-place to enable positioning the longitudinal reinforcement of the framing beams. The beam top reinforcement was placed in sum on top of the precast beams. Fig. 8</p><p>　　As a result, these hooked b

44、ars possessed only about 55 percent of the development length required by Chapter 21 of ACI 318-02. In an attempt to anchor these hooked bars, some designers in Mexico provide closed hoops around the hooks, as shown in F

45、ig. 8. The effectiveness of this approach was also studied in the companion paper.3 Beam to-column joints in the lateral frames of the test structure had transverse beams that were deeper than the longitudinal beams. Thi

46、s made it possible for the top an</p><p>　　Cast-in-place topping slabs in the test structure were 30 mm (1.18 in.) thick and formed the diaphragms in January-February 2005 Fig. 3. Plan and elevation of test

47、structure: (a) Plan; (b) Lateral frame; (c) Transverse frame. Dimensions in mm. Note: 1 mm - 0.0394 in. the structural system. Welded wire reinforcement (WWR) was used as reinforcement for the topping slabs. The amount o

48、f WWR ill the topping slabs was controlled by the temperature and shrinkage provisions of the MCBC. which are simila</p><p>　　It is of interest to mention that the requirements for shear strength in the diap

49、hragms given by these provisions, which are similar to those of ACI 318-89, did not control the design. A wire size of 6 x 6 in. 10/10 led to a reinforcing ratio of 0.002 in the topping slab. The strength of the WWR at y

50、ield and fracture obtained from tests were 400 and 720 MPa(58 and 104 ksi),respectively.</p><p><b>　　外文翻譯</b></p><p>　　一個未完工的二層預(yù)制混凝土結(jié)構(gòu)物的抗震測試</p><p>　　這篇文章是關(guān)于地震和預(yù)制混凝土建筑物設(shè)

51、計的試驗性的研究。墨西哥市里一個帶有雙重系統(tǒng)和代表了一個停車場結(jié)構(gòu)的未完工的兩層的預(yù)制混凝土建筑物被調(diào)查研究。這個結(jié)構(gòu)物在實驗室里用模擬地震荷載測試，結(jié)果失敗了。在一些梁和柱的接頭處，粱底部的縱筋由于尺寸的限制不能屈服。這項研究所強調(diào)的是提高所測試結(jié)構(gòu)物的可觀察的綜合性能。這種性能表現(xiàn)為所測試結(jié)構(gòu)物的墻控制傳力途徑而且能顯著地減少預(yù)制結(jié)構(gòu)所要求的側(cè)向變形。源自于這項研究的預(yù)制混凝土結(jié)構(gòu)抗震設(shè)計標(biāo)準(zhǔn)和規(guī)范細節(jié)被討論。這項研究的最終結(jié)果是能

52、更好地理解這種類型的建筑物的已得知的性能。</p><p>　　在墨西哥，一個兩層的預(yù)制混凝土構(gòu)件建成的預(yù)制混凝土建筑物，在其上加上模擬的地震荷載。在這里描述的是其結(jié)果。在測試結(jié)構(gòu)物中所選擇的結(jié)構(gòu)系統(tǒng)是所謂的雙重類型，其定義就是構(gòu)造墻的結(jié)合點以及梁-柱框架。測試結(jié)構(gòu)物中預(yù)制梁柱之間的結(jié)合是窗型的。這種類型的建設(shè)顯著地用在低的或中等高建筑物中，在這種建筑中在每一樓層中柱子和窗子連在一起。這些“窗”包含頂部和底部的鋼

53、筋。圖1所示的是在墨西哥市中這種類型的一個商業(yè)建筑物。</p><p>　　大多數(shù)的預(yù)制混凝土結(jié)構(gòu)如圖1中所示，縱梁底部的鋼筋不能完全屈服。這是由于在梁-柱接頭中柱的尺寸限制所造成的。為了盡力克服這種缺陷，正如在后面所描述的，在墨西哥一些工程師嘗試著這樣設(shè)計這些接頭，就是通過用箍筋圈住這些鋼筋，這樣做是為了達到所要求的連續(xù)性。然而，這種嘗試在ACI建筑規(guī)范和MCBC中都沒有提到。這些研究的一部分是為了闡述這個觀點

54、。</p><p>　　這項研究的目的是為了提高在實驗室里的預(yù)制混凝土結(jié)構(gòu)屋的可觀察的性能以及為利用諭旨構(gòu)件或預(yù)制結(jié)構(gòu)建議了一個可接受的期望的抗震性能以及從建設(shè)能力的觀點所得出的有吸引力的特征。這篇文章中強調(diào)的所測試結(jié)構(gòu)物中預(yù)制構(gòu)件間的連接處的可觀察的性能以及預(yù)制樓層系統(tǒng)的性能將會詳細講述。</p><p>　　在過去的地震中，在建筑物中造成的可觀察的構(gòu)造和非構(gòu)造的破壞顯示了通過控制結(jié)構(gòu)的

55、側(cè)向位移來降低由地震造成的建筑物的破壞的重要性。在這里還要提到的是，在中等程度的地震中有一些情況下非結(jié)構(gòu)構(gòu)件的破壞相當(dāng)大，盡管構(gòu)造構(gòu)件只有一點破壞或根本就沒有破壞。這種性能和結(jié)構(gòu)物中所要求的過多的側(cè)向位移有關(guān)。</p><p>　　為了減少地震所造成的破壞，以上的討論建議了在結(jié)構(gòu)物中可以方便地使用能控制惻向位移的構(gòu)造系統(tǒng)。這種類型的解決方法就是所謂的雙重系統(tǒng)。Paulay和 priestly的關(guān)于雙重系統(tǒng)的地震反

56、映的研究表明墻的出現(xiàn)降低了框架微系統(tǒng)中結(jié)構(gòu)構(gòu)件的動力要求。同時，在一個現(xiàn)澆的鋼筋混凝土雙重系統(tǒng)上所做的搖擺測試顯示了雙重系統(tǒng)能達到良好的抗震性能的潛力。在這次調(diào)查研究中，雙重系統(tǒng)應(yīng)用在預(yù)制混凝土構(gòu)件上。</p><p><b>　　雙重系統(tǒng)的柔性要求</b></p><p>　　為了使這個工程所研究的被測試結(jié)構(gòu)物的能觀測到的抗震反應(yīng)的以后的分析打好基礎(chǔ)，一個簡單的分析

57、模式被用來提高雙重系統(tǒng)中主要柔性特征要求。</p><p>　　圖2所示的是一個簡單的分析作用在雙重系統(tǒng)側(cè)向荷載反映的結(jié)果。側(cè)向荷載從這種方式標(biāo)準(zhǔn)化，將任一系統(tǒng)中最大的側(cè)向抵抗力聯(lián)合起來。比如，墻和框架導(dǎo)致綜合系統(tǒng)的側(cè)向抵抗力。假設(shè)任一微系統(tǒng)的總的位移量為4和2。在第二種情況下，框架系統(tǒng)假設(shè)為彈性，墻微系統(tǒng)的剛度為框架微系統(tǒng)的4倍。</p><p>　　圖2所示，聯(lián)合系統(tǒng)的側(cè)向變形兼容性由

58、墻微系統(tǒng)的側(cè)向變形量控制，在第一種情況下，假設(shè)雙重系統(tǒng)的總側(cè)向反應(yīng)有一個塑料封套，相應(yīng)的位移系數(shù)是3.3在第二種情況下，框架微系統(tǒng)在彈性力下，起位移系數(shù)是2.5。</p><p>　　這些簡單的例子說明，在以上分析的情況下，由于在雙重系統(tǒng)中框架微系統(tǒng)與墻微系統(tǒng)相比彈性大的多，框架微系統(tǒng)柔性要求更小比墻微系統(tǒng)的該項要求有價值。這項分析結(jié)果在被測試結(jié)構(gòu)物上所做的研究上被證實了，這個證明在這篇文章的后面會討論。有趣的是

59、圖2所示的類型的結(jié)果，Bertero在一個搖擺測試的雙重系統(tǒng)中也發(fā)現(xiàn)了。</p><p><b>　　測試結(jié)構(gòu)物的描述</b></p><p>　　在這次調(diào)查中所用到的被測試結(jié)構(gòu)物是一個兩層的預(yù)制混凝土建筑，是一個位于墨西哥市高地震發(fā)生地帶的有代表的低層的停車結(jié)構(gòu)。原型還未完工，為了簡單起見，一個停車場結(jié)構(gòu)物所需的扶梯在所選的結(jié)構(gòu)物中沒有考慮。如果考慮的話，將占有樓層

60、系統(tǒng)的大面積空間，為了進行結(jié)構(gòu)物的線性或非線性分析，將需要一個非常復(fù)雜的樓層系統(tǒng)模型。</p><p>　　關(guān)于所測試結(jié)構(gòu)物的詳細的尺寸，材料，設(shè)計步驟和建設(shè)描述到處都可以發(fā)現(xiàn)，下面給出了這些信息的一個總結(jié)。</p><p>　　所測試結(jié)構(gòu)物的尺寸和一些特征如圖3所示，其縱向以及相反方位如圖3所示，同時，外部框架包含墻被定義為側(cè)向框架，內(nèi)部框架和單個T梁被定義為中間框架。</p&g

61、t;<p>　　縱向的兩個T梁由相反方向的L型預(yù)制梁支撐如圖3所示，該結(jié)構(gòu)物用預(yù)制框架和預(yù)制構(gòu)造墻組成，后面構(gòu)件的功能是作為主要的側(cè)向荷載抵抗系統(tǒng)，圖4所示的是所測試結(jié)構(gòu)物建設(shè)的早期階段。我們可以看到，在柱和墻上留下了一些窗，是為了以后的預(yù)制梁的裝配。</p><p>　　墨西哥城市建筑規(guī)范所要求的設(shè)計基礎(chǔ)剪力為0.2Wt, Wt是模型結(jié)構(gòu)物的總重，假設(shè)橫載為5.15Kpa，活載為0。2Kpa，模型

62、結(jié)構(gòu)物是按彈性分析的步驟設(shè)計的，比例是按MCBC要求來的，結(jié)構(gòu)物中構(gòu)件總的慣性都考慮了，結(jié)構(gòu)物中除了中間框架的梁（會在以后介紹）以外的所有梁都考慮了剛度補償。</p><p>　　這些分析的結(jié)果表明測試結(jié)構(gòu)物中的構(gòu)造墻將承受65%的設(shè)計側(cè)向荷載，一個用MCBC步驟考慮的結(jié)構(gòu)物的名義上的側(cè)向抵抗顯示這個抵抗力是規(guī)范規(guī)定的側(cè)向抵抗的1。3倍。這只是使結(jié)構(gòu)無承載過度的因素中的其中之一，其它的以后會討論。</p&g

63、t;<p>　　測試結(jié)構(gòu)物的所有構(gòu)件的縱筋都是從420級鋼筋開始破壞的，表一是模型結(jié)構(gòu)物中不同構(gòu)件的混凝土壓柱強度。</p><p>　　圖6，7分別是柱，構(gòu)造墻和基礎(chǔ)的鋼筋詳細情況，應(yīng)提到的是，測試結(jié)構(gòu)物是按MCBC要求設(shè)計的適度柔性結(jié)構(gòu)物。由于這些規(guī)定，測試結(jié)構(gòu)物不需ACI318-02第21章所要求的有邊界部件的特殊的構(gòu)造墻。</p><p>　　預(yù)制的兩層柱是通過埋置在

64、一個插座連接處與預(yù)制基礎(chǔ)相連接的基礎(chǔ)的配筋情況以及設(shè)計步驟和性能在相應(yīng)的文章中討論。</p><p>　　測試結(jié)構(gòu)物的梁-柱接頭是現(xiàn)澆的，為了能安置框架梁中的縱向鋼筋。梁頂部鋼筋是按in-situ分布在預(yù)制梁的頂部.圖8所示的是中間框架中雙T接頭的配筋情況.因為這些T支座和支撐他們的L型梁 在軸A,C上深度相同(見圖3),在雙T座底部的鋼筋不能穿過整個柱深,因為其被相反方向兩的底不鋼筋打斷了.</p>

65、<p>　　所以 ,這些帶鉤的鋼筋只有ACI318-02第21章所要求的55%的發(fā)展長度.為了能錨固住這些帶鉤鋼筋,在墨西哥的一些設(shè)計師沿著鉤用封閉的箍筋箍住,如圖8所示,這種方法的有效 性在相應(yīng)的文章中回研究.</p><p>　　測試結(jié)構(gòu)物的側(cè)向框架中的梁-柱接頭中有相反方向的梁比縱梁還要深.這使的縱梁中頂部,底部的鋼筋能穿過整個接頭,所以這些鋼筋能達到所需要的發(fā)展長度.</p>

66、<p>　　測試結(jié)構(gòu)物中頂部的現(xiàn)澆的板層有30mm厚,也形成了結(jié)構(gòu)系統(tǒng)的圖表.WWR被用作頂部的板層的鋼筋,頂部板層中WWR的數(shù)量由MCBC中溫度和收縮要求控制,這與ACI318-02中的控制要求相似.</p><p>　　有趣的是,由這些規(guī)范所給的圖表中的抗剪強度要求與ACI318-89的要求相似,不控制設(shè)計,鋼筋尺寸是6*6,10/10導(dǎo)致在頂層 的鋼筋比率為0.002,WWR的測試屈服和破壞強度分