外文翻譯--組合作用的基礎(chǔ)及抗剪連接-文庫(kù)吧
2025-04-17 06:05 本頁(yè)面
【正文】 the beamslab 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 fatigue 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 shear 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. been pointed out that the paradoxical situation exists that if shear connection is provided it may in fact not e into operation because the natural bond takes all the is provided it may in fact not e into operation because the natural bond takes all the shear force, and so `if sufficient shear connectors are provided then they are unnecessary39。. 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 that 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 purposemade shear connector was not available. In any mechanical connection system it is possible to identify parts which transfer horizontal shear and parts which tie the slab down to the beam. Generally, horizontal shear resistance is the ruling criterion of shear connector action and with this in mind mechanical connectors may be classified into three main groupsrigid, flexible and bond. Limit State Design of Brickwork The basic aim of structural design is to ensure that a structure should fulfill its intended function throughout its lifetime without excessive deflection, cracking or collapse, and this aim must of course be met with due regard to designer is assisted in his task by the availability of a code of practice which is based on accumulated experience and research. Up to the present time, such codes have sought to ensure the safety and serviceability of masonry structures by specifying permissible stresses for various types and binations of materials. Thus codes generally give basic pressive stresses for a range of brickmortar binations。 the basic stress in a particular case has then to be adjusted for the slenderness ratio of the element and the eccentricity of the loading. The basic stresses are derived
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