土建專業(yè)畢業(yè)論文外文翻譯

1、<p><b>　　外文原文1</b></p><p>　　Increased Snow Loads and Wind Actions on Existing Buildings: Reliability of the Norwegian Building Stock</p><p>　　Vivian Meloysund, Ph.D. ; Kim Rober

2、t Liso, Ph.D. ; Jan Siem ; and Kristoffer Apeland</p><p>　　Abstract: Results from an investigation of snow loads and wind actions on 20 existing buildings in Norway are presented. The objective has been to i

3、nvestigate to what extent existing buildings meet current regulatory requirements relating to safety against collapse owing to snow loads or wind actions. Eighteen buildings have a utilization ratio of more than 1.0 unde

4、r current regulations. The new design rules have led to most of the buildings investigated having reduced safety against collapse ow</p><p>　　CE Database subject headings: Bearing capacity; Buildings; Climat

5、ic changes; Norway; Reliability; Snow loads; Structural design; Structural safety; Wind loads.</p><p>　　Introduction</p><p>　　Background</p><p>　　Large snow loads on during the wint

6、er of 1999/2000 led to the collapse of several buildings in northern Norway. The accident at Bardufoss Community Centre, where the roof caved in and claimed three lives, was the most serious of these accidents (Fig.1). T

7、he most important causes of this collapse were a faulty construction of the roof when the building was erected and larger snow loads on the roof than it was designed for.</p><p>　　Principal Objectives and De

8、limitations</p><p>　　The principal objective of the investigation has been to obtain a reliable indicator as to whether existing buildings in Norway meet current regulatory requirements concerning safety aga

9、inst collapse owing to snow loads and/or wind actions, and also to establish a basis for the analysis of future climate change impacts on the Norwegian building stock. The analysis encompasses design documentation invest

10、igations and field studies of 20 existing buildings in five high-snowfall and five high-wind m</p><p>　　Building Regulations and Design Codes</p><p>　　Development of Design Codes for Snow Loads

11、and Wind Actions</p><p>　　The building regulations of December 15, 1949 referred to a general snow load on roofs corresponding to 1.5KN/m. This value could be reduced or increased by the individual building

12、authority with the Ministry’s approval. The importance of the shape of the roof for the size of the snow load on the roof was calculated in a simple way. Structures should normally be designed for a wind pressure equal t

13、o 1.0 KN/m, while a wind pressure equal to 1.5 KN/m should be used in exposed areas. In heavily exp</p><p>　　In NS 3052 (Standard Norway 1970) snow maps were introduced showing zones with roof snow loads val

14、ues of up to 1.5 KN/m, between 1.5 KN/mand 2.5 KN/m, and above 2.5 KN/m. Four curves for the wind pressure were introduced: Curves A, B, C, and D, as seen in Fig.2. The code quoted many more-detailed rules for the wind s

15、hape factors for the lee and windward walls was in the code also set to 1.2. Compared to the building regulations of 1949, the changes in NS 3052 largely implied a reduction in the w</p><p>　　In NS 3497-4 (S

16、tandards Norway 2002a), a classification of the whole country has been carried out so that wind exposure for all 434 municipalities is defined. Exposure is defined by means of a reference wind velocity (varies between 22

17、 m/s and 31 m/s). Roughness of the terrain in an area 10 km against the wind direction is important for the wind pressure (in the code called the gust velocity pressure). The code defines five such categories of terrain

18、roughness. Other parameters of importance for</p><p>　　In this regulation amendment process, NS 3490 (standards Norway 1999) prescribes a 50-year return period for environmental loads. The partial factors fo

19、r environmental loads are set to 1.5. A reduction factor kby which the partial factor must be multiplied is introduced.</p><p>　　The extensive revisions of the codes have increased the level of detail in the

20、 regulations considerably. The objective is to achieve a safety level in accordance with Table 2. In other words, the intention is to achieve a more uniform safety level for buildings that have the same reliability class

21、 even if they are built in different places, and also to obtain different safety levels for structures classified in different reliability classes.</p><p>　　A thorough description of the historical developme

22、nt of design loads for wind actions and snow loads is presented by Meloysund et al.(2004).</p><p>　　Selection Criteria and Methodology</p><p>　　Limits of Use</p><p>　　The consequenc

23、es of a collapse are greater in buildings in which many people are present than in buildings with few people. A collapse in public buildings such as sports halls, and the like has. Therefore, greater consequences than, f

24、or example, in storage facilities in which it is less probable that people will be present. This is also apparent from the reliability approach set out in numbers in Table 2 in which, under current rules, more stringent

25、requirements are imposed on structures whose c</p><p>　　Material Use and Geometry</p><p>　　For light roofs, the specific weight is open low compared to the snow load that the roof is required to

26、 withstand. If the snow load exceeds the design value, the load has increased virtually the same percentage as the snow load. If the specific weight had been high, the percentage increase would have been much smaller. Li

27、ghtweight structures are, therefore, more vulnerable to an increase in snow load above the load for which the structure is designed than heavy structures. In other words, heavy </p><p>　　Another selection cr

28、iterion is the maximum span of a building. The consequences of a collapse in buildings with large spans are usually great.</p><p>　　A number of types of construction may be sensitive to unbalanced loads. Whe

29、n the structures are being cleared of snow, this may in the worst case make the stresses in the structure larger than before the snow clearance started. There are many examples of snow clearing leading to the collapse of

30、 structures. It is, therefore, important to know whether the structure can carry the unbalanced load that arises during snow clearance.</p><p>　　Year of Construction, Loads, and Geographical Location</p&g

31、t;<p>　　Design loads on buildings have changed considerably in the period from 1949 to today. The year of construction may, therefore, tell something about the building’s safety level. In general, older buildings

32、in high-snowfall areas may have a lower safety with respect to snow loads than newer buildings. The difference in safety level with respect to wind action is probably somewhat less.</p><p>　　The safety level

33、 is probably affected mostly in areas that are heavily exposed to the environmental loads, when snow loads and wind actions in the regulation are increased from general loads that have applied to the entire country to di

34、fferentiated loads that are adjusted to the actual environmental load variation in Norway. Increased wind actions, therefore, probably have the greatest consequences for coastal areas from northwest Norway northward. Loc

35、ally roughness of terrain and topography and</p><p>　　Construction Process</p><p>　　Prefabricated structures are often imported. It has been claimed that design calculations do not always meet t

36、he design rules set out in Norwegian codes and that many structures have been designed for relatively small snow loads compared to Norwegian requirements. Structures have been imported from countries such as Denmark that

37、 are designed for snow loads well below those required in Norway.</p><p>　　Selected Buildings</p><p>　　Based on the assessments above, 20 buildings were selected Table 3 lists the municipality i

38、n which the buildings were selected, the building type, and the requirement that currently applies to characteristic snow load on the ground and to the reference wind velocity. As shown in Table 3, attempts have been mad

39、e to keep the selected buildings as anonymous as possible. Problems in obtaining the necessary documentation implied that an investigation of only one building was conducted in two of the m</p><p>　　Three of

40、 the buildings were constructed in the period before 1970, eight were built in the period 1970-79, and nine were built in the period after 1979. This implies that the loads are determined by the 1949 building regulations

41、 for three of the buildings, by NS 3052 for the buildings, and by NS 3479 for nine of the buildings.</p><p>　　Project Documentation Investigation and Field Study</p><p>　　Calculation models, loa

42、ds, forces, and solutions used when the buildings were constructed have been investigated. The forces in the structure were then determined in accordance with new load requirements, and the capacities checked in accordan

43、ce with new load requirements. In light of these analyses, the structure’s utilization ratio has been determined in accordance with new calculation rules, and the need for reinforcement assessed.</p><p>　　On

44、 site, whether the structures have defects or deficiencies that are not apparent from the project documentation of whether or not the construction was in accordance with the documentation, and whether or not there were w

45、eaknesses in the structure owing to reduced durability or due to reconstruction.</p><p><b>　　Results</b></p><p>　　Geometry and Material Data</p><p>　　External dimensions

46、, maximum spans, and the material of the main load-bearing structures are shown in Table 3. The building’s external dimensions are quoted as width, length, height, and roof slope. The height indicates the cornice height

47、for buildings with other roof shapes. Additions or extensions that are not included in the assessments have not been included in the dimensions.</p><p>　　As is apparent from the values in the table, the buil

48、dings selected can be characterized as medium-sized buildings with medium spans. The roof slope varies between 0 and 26°. All the buildings are of low height relative to their width and length. Essentially, the buil

49、dings included in the investigation are light-weight constructions, because buildings of this type are empirically expected to be most vulnerable.</p><p>　　Availability and Scale of the Documentation</p&g

50、t;<p>　　When the investigations started, the writers were prepared for the fact that it might be difficult to obtain full documentation on the load-bearing structures in the buildings, which in this context have b

51、een defined as design calculations and structural drawings. Although there were requirements in the building regulations up to 1997 that design calculations should form part of the building licence application, it is wel

52、l known that many municipalities have not enforced this requirement.</p><p>　　In light of the information supplied by the municipalities, a total of 20 buildings were selected. Buildings with available docum

53、entation were given priority. It was decided at an early stage that built-in structures would not be opened and investigated. It was therefore necessary to obtain the best possible documentation so that built-in structur

54、es were known from the documentation. If there were links between available documentation, such selection criteria would lead to the buildings most ext</p><p>　　A lack of important documentation for building

55、s included in the investigation can affect the results. The calculations must then be based on our own assumptions and assessments, which may be different from the constructor’s (see Table 3 for information on available

56、structural calculations). Deficient information on hidden, structural measures may then be significant. A lack of documentation makes it difficult to uncover the reason for chosen structural designs unambiguously.</p&

57、gt;<p>　　Changes in Design Snow Loads and Wind Actions for Selected Buildings</p><p>　　Current requirements for characteristic snow loads on the ground and characteristic gust velocity pressure agains

58、t the selected buildings are presented in Table 3. In Table 3, Andoy 2, Frana 1, and Nittedal 1 are quoted with “a” and “b” versions. Here, “a” means the original building and “b” means additional (or extensions). Furthe

59、rmore, the changes in design loads on the buildings are shown, where current requirements are compared with the requirements that applied when the building was being d</p><p>　　As Table 3 indicates, only two

60、 buildings in two municipalities experienced reduced design snow loads, one experienced an unaltered load level, while the rest experienced increased snow loads. The changes in the rules for snow loads have, therefore, b

61、een of major importance to the requirement concerning design snow loads on most of the buildings that have been investigated. Buildings with a low roof slope dominate the investigation. Pitched roofs slopes of between 15

62、 and 60°have been given reduce</p><p>　　The changes in wind action rules have not been as important as the change in the snow load rules for the design loads on the buildings in investigated. As Table 3

63、 shows, the changes in the rules have only resulted in a significant increase in the wind action on the buildings in the coastal municipalities of Andoy and Frana. The buildings included in the investigation were low in

64、height relative to their width and length. For buildings with this form, the sum of the shape factors against the wind</p><p>　　Discussion</p><p>　　As mentioned earlier, the selected buildings i

65、n the investigation are building types regarded as being especially exposed to increasing snow loads and wind actions. The exposed building types amount to 5% of the total bulk of buildings in Norway (11% of total buildi

66、ng floor area).</p><p>　　Ninety percent of the buildings investigated have too low a capacity when compared with current design rules. Thus, potentially 4.5% of the total bulk of buildings in Norway may have

67、 too low a capacity according to current regulations. The design snow loads have increased for 95% of the investigated buildings, indicating an increase in design snow loads for 4.7% of the total bulk of buildings. Fifty

68、-five percent of the investigated buildings have a higher utilization ratio than load increase, wh</p><p>　　Conclusions</p><p>　　The principal objective has been to obtain reliable indicators as

69、 to whether existing buildings in Norway meet current regulatory requirements concerning safety against collapse as a result of snow loads and/or wind actions. Some clear indications of aspects that ought to be considere

70、d as a represented as a representative trend for the building types investigated have been found.</p><p>　　Eighteen out of 20 buildings have a utilization ratio of more than 1.0 (90% of the buildings investi

71、gated). The design requirements for 95% of the buildings have increased since they were built. Nevertheless, one would assume that the buildings had built-in reserve capacities resulting in fewer buildings experiencing a

72、 utilization ratio of more than 1.0.</p><p>　　Scenarios for future climate change indicate both increased winter precipitation and increased temperature, and will result in changes regarding snow loads on ro

73、ofs in parts of the country. An increase in frequency of strong winds in areas also exposed today is also estimated. According to these scenarios the future reliability of buildings in these areas could decrease.</p&g

74、t;<p>　　Acknowledgments</p><p>　　This paper has been written within the ongoing SINTEF Research and Development Programme “Climate 2000-Building Constructions in a More Severe Climate” (2000-2006), st

75、rategic institute project “Impact of climate Changer on the Built Environment” (Liso et al. 2005). The writers aratefully acknowledge all construction industry partners and Research Council of Norway. Special thanks are

76、extended to Professor Jan Vincent. Thus, Professor Karl Vincent Hioseth, and Professor Tore Kvande for comments o</p><p>　　References</p><p>　　Karl, T. R., and Trenberth, K.E. (2003). “Modern gl

77、obal climate change.” Science, 302 1719-1723</p><p>　　National office of Buildings Techolgy and Administration. (1993). “Orkan 1992.” Norwegian Building Research Insititue, Oslo, Norway (in Norwegian).</p

78、><p>　　.Standards Norway. (1999). Design of structures Requirements to reliability, NS 3490, 1st Ed., Standard Norway, Oslo, Norway (in Norwegian).</p><p>　　Standards Norway. (2002a). Design of str

79、uctures Design actions1st Ed., Standard Norway, Oslo, Norway (in Norwegian).</p><p>　　McCarthy, J.J., Canziani, O.F., Leary, N.A., Dokken, D.J., and White, K.S., eds. (2001). Climate change 2001: Impacts, ad

80、aptation and vulnerability, Cambrige University Press, Cambriged, U.K.</p><p><b>　　中文翻譯1</b></p><p>　　現(xiàn)有的建筑物上增加的雪荷載和風(fēng)荷載效應(yīng)：挪威建筑物可靠性分析</p><p>　　麥勞舒維維安,博士; 金羅伯特利索，博士; 簡瑟姆;

81、和阿佩蘭帕爾森</p><p>　　摘要：對來自在挪威的20個現(xiàn)有建筑物上的一個雪荷載和風(fēng)荷載效應(yīng)的調(diào)查結(jié)果分析。由于存在雪荷載或風(fēng)荷載，所以需要調(diào)查在哪些范圍內(nèi)的現(xiàn)有的建筑物會與現(xiàn)有的規(guī)范要求或者抵抗倒塌的安全度有關(guān)。十八個建筑物在現(xiàn)在的規(guī)范之下有一個超過1.0的利用比。新的設(shè)計規(guī)范已經(jīng)開始應(yīng)用到大部分的建筑上，與現(xiàn)在規(guī)范，對于雪荷載和風(fēng)荷載效應(yīng)，對于減少坍陷的安全性有較好的安全度。當(dāng)評估一個國家的規(guī)劃具有哪些

82、可能結(jié)果的時候，建筑物的大部分的數(shù)據(jù)依照現(xiàn)行的房屋建筑規(guī)范來評估，那么可靠性是很低的。對未來的氣候變化的研究表明雪荷載和風(fēng)荷載在很大程度上會有增加的趨勢，大面積的屋頂也會在強烈的風(fēng)荷載下需要承受更多的危險。因此，在將來這些建筑物的可靠性將會降低。</p><p>　　關(guān)鍵字: 承載力； 建筑物； 氣候上的變化； 挪威； 可靠性； 雪載重； 結(jié)構(gòu)設(shè)計； 結(jié)構(gòu)的安全性； 風(fēng)荷載</p><p>

83、;<b>　　緒論</b></p><p><b>　　背景</b></p><p>　　在1999/2000年的冬天，挪威北部的巨大雪載導(dǎo)致部分建筑物倒塌。在Bardufoss社區(qū)活動中心的意外事件中，屋頂塌陷甚至造成三人死亡,這是所有這類性質(zhì)的意外事件中最嚴重的（圖1）。當(dāng)該建筑物建成后，屋頂上的雪載就超過其原來設(shè)計當(dāng)初的標準荷載，而且此坍陷

84、的最重要的因素之一是在屋頂上有一個構(gòu)造過失。</p><p><b>　　圖1</b></p><p><b>　　主要目標和定界線</b></p><p>　　調(diào)查的主要目標是獲得關(guān)于雪荷載或/和風(fēng)荷載的作用下，以及在現(xiàn)行的規(guī)范標準約束下，挪威現(xiàn)有建筑抵抗塌陷的可靠性研究調(diào)查。以及，在未來挪威氣候改變的條件下，如何分析并

85、建立一個原理和模型。本次調(diào)查分析包括設(shè)計文件，20座曾經(jīng)經(jīng)歷過五次較大雪載作用的，五次強風(fēng)荷載作用的，至今仍然存在的建筑物。統(tǒng)計資料包括了大約三百七十萬在挪威注冊登記建筑物的建筑類型，建筑年限，地質(zhì)資料。特別需要注意的是那些無遮掩，完全暴露在風(fēng)荷載或者雪荷載作用下的建筑物。評定是否合理那要決定于規(guī)范中的一些數(shù)據(jù)在設(shè)計中使用是否準確，理論上的參數(shù)是否包括在正常范圍之內(nèi)。調(diào)查把重心集中在評估建筑物的主要負荷-支承結(jié)構(gòu),或者更小的范圍甚至可以

86、僅是副載重-支承結(jié)構(gòu)。表1列舉了各年份挪威各地區(qū)所發(fā)生塌陷事故的建筑。</p><p>　　表1 主要由雪載引起的塌陷事故</p><p><b>　　房屋建筑設(shè)計規(guī)范</b></p><p>　　關(guān)于雪荷載和風(fēng)荷載效應(yīng)的荷載規(guī)范</p><p>　　1949年12月15日發(fā)布的房屋建筑規(guī)范在對于雪荷載的設(shè)計時屋頂雪荷載

87、大致在1.5KN/m左右。在單獨建設(shè)的房屋上，不管這個估算是減少了還是荷載增加了都需要由政府權(quán)威部門批準才可以執(zhí)行。屋頂上的雪荷載與屋頂?shù)男螤钣嘘P(guān)，但是其荷載標準值大小卻以簡單的方法來計算。一般正常的建筑物設(shè)計中風(fēng)壓是等于1.0 KN/m，而無遮掩部分的面積，其風(fēng)載應(yīng)該要等于1.5 KN/m。完全暴露于風(fēng)壓作用下的建筑面積，建設(shè)的主管當(dāng)局可以批準增加這些風(fēng)壓荷載的大小。一個封閉建筑的迎風(fēng)和背風(fēng)的系數(shù)總和可以是1.2。</p>

88、<p>　　在1970年挪威建筑規(guī)范NS3052中，是由雪載圖來說明哪些區(qū)域雪載達到1.5 KN/m，哪些在1.5KN/m和2.5 KN/m之間, 哪些在2.5 KN/m以上。風(fēng)荷載則是由四種曲線把各區(qū)域分為A,B,C,D四種，在圖2中可以看到。規(guī)范應(yīng)用更多更詳細的標準數(shù)據(jù)來指出迎風(fēng)和背風(fēng)墻的系數(shù)也是1.2。與1949年的房屋建筑規(guī)范相比，在NS 3052中，不同的是它更多的指明了在空曠地區(qū)的風(fēng)速壓力是相對較小的。同時，在

89、NS3052中，也介紹了部分傳遞系數(shù)，當(dāng)風(fēng)壓作用時的部分傳遞因數(shù)被設(shè)定成1.5的時候，雪荷載的部分傳遞因數(shù)則要設(shè)定成1.6。</p><p>　　在2002a挪威標準規(guī)范中，整個國家的434個行政區(qū)域都被分區(qū)并詳細的說明了風(fēng)壓標準規(guī)范。由風(fēng)的參考速度來定義方位(在22 m/s和31 m/s之間變化)。在迎風(fēng)的10km區(qū)域，地面的粗糙程度對風(fēng)壓是很重要的。在規(guī)范里成為速度風(fēng)壓，也有五個關(guān)于地形粗糙程度的定義。另外其

90、它重要的因素包括風(fēng)向、建筑高度、地形也需要列在考慮范圍之內(nèi)。</p><p><b>　　圖2</b></p><p>　　在這個規(guī)范的修正方法中，挪威標準規(guī)范1999（NS 3490）則為環(huán)境的負荷規(guī)定一個50年的重現(xiàn)周期。環(huán)境負荷部分的傳遞系數(shù)被設(shè)定成1.5。部分的傳遞系數(shù)要乘以一個縮減系數(shù)k。</p><p>　　規(guī)范的廣泛修訂已經(jīng)相當(dāng)大

91、的增加了規(guī)范的詳細程度。目的是為了符合表2的要求，從而達到一個安全的水平。換句話說，目的是為建筑物能達到一個相對的可靠度要求而制定了一個比較統(tǒng)一的安全等級要求，即使建筑物在不同的區(qū)域建造,但如果有些結(jié)構(gòu)處于不同的可靠度等級，那么就具有不同的安全水平。</p><p>　　表2 可靠性等級、建筑類型、可靠性系數(shù)和塌陷概率</p><p>　　meloysund等人詳細描述風(fēng)荷載效應(yīng)和雪荷載的

92、設(shè)計荷載發(fā)展歷史。</p><p><b>　　選擇標準及方法</b></p><p><b>　　使用范圍</b></p><p>　　在人多的時候發(fā)生建筑塌頂?shù)暮蠊热松俚臅r候要嚴重的多,因此在公共建筑，如體育館，若是發(fā)生類似的事件，后果是非常嚴重的。但是要是在倉庫里發(fā)生類似的倒塌事件，那后果的嚴重性將會減少很多，這

93、在規(guī)范中也有表述。在現(xiàn)行的規(guī)范下，對于易產(chǎn)生嚴重后果的公共建筑則有更強硬的強制性。</p><p><b>　　材料使用與截面尺寸</b></p><p>　　相對于雪荷載來說，輕型屋頂?shù)谋戎厥呛苄〉?，但仍是要承受住雪荷載的作用。如果當(dāng)雪荷載標準值超過設(shè)計標準值時，那么承受荷載的能力要隨著雪荷載增大而增加相同的百分比。如果特定的承載力已經(jīng)很高了，那么相應(yīng)的增長可以相對

94、少。因此，輕型結(jié)構(gòu)相對于重型結(jié)構(gòu)來說，前者更適用于積雪量超過負荷而設(shè)計的結(jié)構(gòu)，而后者則比較困難。換句話說，重型結(jié)構(gòu)有較大的內(nèi)置的安全，當(dāng)負荷增加超出本身的承載能力時，則還要考慮其內(nèi)置的安全。</p><p>　　另一個選擇的標準是建筑物跨度的大小，一幢建筑物若是跨度很大，那它往往容易倒塌。</p><p>　　很多類型的工程對不平衡受荷是相當(dāng)敏感的。當(dāng)結(jié)構(gòu)在清理積雪的時候，那就是前面所講的

95、結(jié)構(gòu)所承受的荷載大于清理前的情形。而且有很多清除積雪的時候?qū)е陆ㄖ锏顾睦右彩谴嬖诘摹Ｒ虼?，重要的是要知道在清理積雪期間，建筑物是否可以承受不平衡的荷載。</p><p>　　工程年限、荷載、地質(zhì)情況</p><p>　　從1949年到今天，建筑荷載設(shè)計已經(jīng)有很大的變化。因此，建設(shè)工程的時間可能會告訴我們建筑物的安全水平。一般來說，在高降雪地區(qū)老的建筑物比同樣地區(qū)新的建筑物安全水平要低

96、一些。至于風(fēng)荷載，不同安全等級的建筑也稍微是不同的。</p><p>　　在遭受嚴重的環(huán)境荷載的區(qū)域中安全水平或許已經(jīng)被影響而下降,現(xiàn)在的雪荷載和風(fēng)荷載效應(yīng)的設(shè)計已經(jīng)從過去適用于整個國家區(qū)域，調(diào)整到挪威真實的環(huán)境荷載變化，從而一般情況下荷載標準值都是需要增加的。因此，在挪威西北部的北方海岸區(qū)域，風(fēng)荷載設(shè)計中大多比別的區(qū)域都是較大的。建筑物地方性以及所在地方的地質(zhì)粗糙程度也是研究雪荷載和風(fēng)荷載的重要數(shù)據(jù)資料。<

97、;/p><p><b>　　構(gòu)造方法</b></p><p>　　預(yù)制結(jié)構(gòu)現(xiàn)在仍然在使用中，它的結(jié)構(gòu)設(shè)計計算也不一定按照設(shè)計的標準，許多結(jié)構(gòu)都是按照挪威實際的雪荷載來設(shè)計的。許多需要進行雪荷載設(shè)計的結(jié)構(gòu)也可以請國外關(guān)于雪荷載設(shè)計比較有成就的國家來做，比如像丹麥。</p><p><b>　　選中的建筑物</b></p&g

98、t;<p>　　基于以上的調(diào)查評估，從所有建筑物中挑選20座建筑物，說明了建筑物所在的地區(qū)，建筑物的類型和建筑所在地方的參考風(fēng)速度及常遇的雪荷載。如表3所示，這些已經(jīng)被挑選的建筑物都是不向外泄露的。而問題是如何獲得這些必要的文件。</p><p>　　其中三座建筑物是1970年以前建造的，八座建筑物是1970-79年之間建造的，九座建筑物是1979年以后建造的，這表示這三座建筑物的荷載是由1949年

99、建筑規(guī)范決定，而八座建筑物是1970年建筑規(guī)范決定，最后那九座建筑物是由1979年建筑規(guī)范決定的。</p><p>　　工程文件研究以及現(xiàn)場研究</p><p>　　經(jīng)對建筑物在建造的時候使用的計算模型、荷載、荷載影響力、解決方案的調(diào)查研究。荷載影響效應(yīng)是與新的荷載要求相一致，承載力也與新荷載的要求相一致。經(jīng)過這些分析，結(jié)構(gòu)的利用比已經(jīng)與新的計算規(guī)范相一致，同時要加強利用比。</p&

100、gt;<p>　　表3 挑選建筑的數(shù)據(jù)概要</p><p><b>　　結(jié)果</b></p><p><b>　　截面尺寸與材料數(shù)據(jù)</b></p><p>　　外部尺寸，最大跨度，主體結(jié)構(gòu)的材料見表3。建筑物的外部尺寸包括寬度、長度、高度和屋頂斜坡。高度為建筑物房屋屋頂檐口到地面的高度，所有超出的或者是延伸