1、 毕 业 设 计（论 文） 外 文 参 考 资 料 及 译 文 译文题目： 学生姓名： 学 号： 专 业： 所在学院： 指导教师： 职 称： 年 月 日 Fundamentals of Composite Action and Shear Connection The evolution of satisfactory design methods for composite beams has been a slow process, requiring much theoretical and experimental work in order to provide economic a
2、nd, at the same time, safe design criteria. The purpose of this Chapter is to describe in some detail the more important fundamentals which have to be taken into account in the design of composite structures. Historically the first analysis of a composite section was based on the conventional assump
3、tions of the elastic theory which limit the stresses in the component materials to a certain proportion of their failure stresses (yield in the case of steel, crushing in the case of concrete). The assumptions inherent in the elastic method are similar to those for ordinary reinforced concrete. In r
4、ecent years the concepts of the ultimate load design philosophy have been applied to composite action and a body of experimental evidence has shown it to be a safe, economical basis on which to proportion composite sections. Although at the present time ultimate load design methods are directly appl
5、icable only to buildings and not to bridges there seems no reason to doubt that in time the restriction will disappear. Before dealing in detail with the two design approaches (elastic and ultimate load) basic points require consideration. A clear understanding of the way in which the component mate
6、rials, steel concrete and shear connection react to applied load is an essential preliminary to full analysis of the composite section. Of primary importance are the stress strains relationships, which must of necessity be the product of carefully controlled experiment. These experimental results ar
7、e not generally suited to direct application and so simplifications and idealisations are adopted in practice. The use of computers has made it possible to reduce the amount of idealisation required with the result that computer experiments can now be performed using material stress-strain relations
8、hips of considerable complexity. Composite action between steel and concrete implies some interconnection between the two materials which will transfer shear between them. In reinforced concrete members the natural bond of concrete to steel is often sufficient to do this, although cases do arise in
9、which additional anchorage is required. The fully encased filler joist also has a large embedded area which is adequate for full shear transfer. However, the situation is quite different with the common type of composite beam in which the concrete slab rests on, or at best encloses, the top flange o
10、f the steel beam. It is true that there will initially be shear transfer by bond and friction at the beam-slab contact surface. There is ,however, a tendency for the slab to separate vertically from the beam and, should this occur, horizontal shear transfer will cease. m A single overload or the fat
11、igue effect of pulsating loading may destroy the natural bond, which once destroyed cannot be reconstituted. The imponderable nature of such shear connection is clearly undesirable； some form of deliberate connection between beam and slab is required with the two objects of transferring horizontal s
12、hear and preventing vertical separation. A, natural bond will exist in the presence of shear connection but it is neither desirable to count on its existence nor possible in all cases to calculate its value. Thus shear connection must be provided to transfer all the horizontal shear force. It has. b
13、een pointed out that the paradoxical situation exists that if shear connection is provided it may in fact not come into operation because the natural bond takes all the is provided it may in fact not come into operation because the natural bond takes all the shear force, and so if sufficient shear c
14、onnectors are provided then they are unnecessary. The evolution of shear connection devices has been slow and has necessitated a large volume of experimental work on the static and fatigue properties of a wide range of mainly mechanical connectors. It soon appeared clear to early research workers th
15、at some form of connector fixed to the top flange of the beam and anchored into the slab was necessary. Caughey and Scott in 1929 proposed using, amongst other things, projecting bolt ends. Since then a wide variety of types of mechanical connector has been used in experiment and practice. To some extent the proliferation of types has been .the result of steel fabricators using sections which came easily to hand, since initially a purpose-made
