房屋结构工程专业英语.ppt

1、Unit 11 11单元Steel Members钢零件，tension Members are found in bridge And roof trusses，towers，bracing systems，And in situation whereThe selection of a section to be used as a tension member is one of The simplest problems es Tered in design . as there is no danger of buckling，The desselection of a sectio

2、n of a bucklingtension members，then it is necessary to select a steel section that provides the required area . though these introductory calculations for tension members ar Simple由于没有偏转的危险，设计者只需计算零部件施加的分解力，然后除以设计应力以确定所需的有效横截面面积。然后，必须选择提供所需面积的钢截面。这些池组件的介绍性计算非常简单，但即使学生开始有设计概念，并进入了很多LRFD手册，也能实现这些重要目标。

3、load resistance factor design(lrfd)钢结构设计规范(载荷阻力设计)allowable stress design(ASD)，One of the simplest forms of tems拉构件最简单的形式之一是圆钢，但连接到许多结构时存在困难。过去经常使用圆钢，但现在只偶然用于支撑系统、轻型桁架和木结构。圆钢不受设计师欢迎的一个重要原因是过去经常使用不当，名声受损。但是，如果设计和安装得当，在很多情况下都很满意。the average size rod has very little stiffness and may quite easily sag u

4、nder its own weight，Injuring the appearance of the structure . the thrightanother Ds is the difficulty of fabricating them with the exact lengths required and the consequent difficulties of installation。一般来说，尺寸圆钢几乎没有刚度，以前用于桥梁的带螺丝的圆钢经常松，发出嘎吱的声音。圆钢的另一个缺点是很难按照所需的正确长度制作，因此很难相应地安装。when rods are used in w

5、ind bracing，it is a good practice to produce initial tension in them，As this will tighten up the structure and reducturea common rule of thumb used is to detail the rods about 1/16in . short for each 20 ft . of length . another very satis factory method involves tighteningpart 8 of the lrfd manual p

6、rovides detailed information for these devices要获得初始张力，杆件的设计可以短于所需的长度。牙齿方法对钢材制作者来说几乎不是问题。一种茄子的一般经验方法是设计牙齿圆钢时，每20英尺长度减少约1/16英寸，另一种满意的方法是用套筒螺母拧紧圆钢。有关这些方法的详细信息可在LRFD文档的第8部分中找到。the preceding discussion on rods should illustrate why rolled shapes such as angles have supplanted rods for most applications.O

7、f steel structures，tension members consisted of rods，bars，and perhaps cables.today，Although the use of cables is increasing今天，悬吊屋顶结构中的电缆使用量不断增加，但拉构件通常包括由单角度、双角度、T形钢、槽、W形钢或薄钢板或轧制型钢组成的型钢。牙齿组件比旧的更好，更结实，更容易连接。另一种常见的拉伸构件是焊接的薄钢板或扁钢，对发射塔、广告牌、人行桥和类似的结构非常满意。the tension members Of steel roof trusses may consi

8、st Of single angles as small as 21/2 2 2 1/4 for minor members . a more satisfactory members，where steel sections(钢)are used back-to-back in to They should be connected every 4 or 5 ft。to prevent rattling，Particularly in bridge trusses . single angles and double angles are probably the most common t

9、ypes of tension members in USS(约翰f肯尼迪，北美国电视电视剧，女)钢背对背的方式，特别是要每4英尺或5英尺连接一次，以免桥桁架发出嘎吱的声音。单角度和双角度可以是拉伸零部件中最常用的类型。在焊接桁架中使用结构T形钢可以轻松连接腹板，从而获得满意的弦。For bridges and large roof trusses tension members may consist of Channels，w or s shapes，or even sections built up from some combination，12.25 in。and 12.12 in。Respectively)while The s sections of a certain nominal size all have The same depths . for instance，the S12 50，The S12 40.8 and the S12单通道很少偏心，并且容易连接，所以经常使用。相同重量的W型钢比S型钢更坚固，但W型钢由于厚度变化，可能存在连接不利的条件。例如，W12 79、W12 72和W12 65的厚度分别为12.38英寸、12.25英寸和12.12英寸，某些名义尺寸S型钢的厚度均相同。例如，S12 50、S12