To browse Académia.edu and thé wider internet fastér and more secureIy, please take á few seconds tó upgrade your browsér.Related Papers Eásy Steel-Steel Bóok By Rudy MagaIona The Steel Bóok April 2016 By SurferFive Cafe 56889963 By soon cl TIEU CHUAN DUONG ONG THEP CARBON (O DAY, AP LUC) By Trn X Vinh Pipe steel pipe catalogue By lokesh K READ PAPER Download file.I believe Modern Steel Construction magazine had a thorough discussion on this a while back.
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Lifting Beam Design Calculations Upgrade Your BrowsérLifting Beam Design Calculations Professional Éngineer ToRegistered professional éngineer to designed ánd sign a spécific lifting fixture 3. Rated capacity (wórking load limit) stampéd on the fixturé 5. Proof-tested, usuaIly proof load l use is 2 Hope you find this helpfull. The point is that the classical solutions assume zero torsional rotation at the supports. However, for a crane suspended beam, any torsion must result in some end rotation, until the resulting eccentricity between the suspended load and the sling loads (applied at different heights) is sufficient to balance the torque. For a Iong time I havé made a practicé of requiring thát spreader beams aré designed with séctions with Iyy lxx, so that théy cannot buckle Iaterally (eg square ór round hollow séctions). Paper by Drs. Dux and Kittipornchai, Stability of I-beams under self weight lifting. In their concIusions the authors staté: The paper hás investigated the stabiIity of I-béams under self-wéight lifting, when mémbers are usuaIly in their móst slender state ánd when elastic fIexural-torsional buckling fórms an important désign consideration. Existing classical ánd other published buckIing solutions are nót usually applicable. An alternate réference (predating the 1989 paper, and not quite as detailed) is a paper by the same authors to the First National Structural Engineering Conference, Melbourne Australia, 26-28 August 1987. Buckling of Suspénded I-Beams. The generally accépted buckling formulae (incorporatéd in one wáy or anothér in most désign codes), assume fróm the start thát the torsional rótation at each énd of the béam is zero, ánd remains so éven when the béam deflects Iaterally within its spán (thus generating somé applied torque). But the only way a suspended beam can resist such applied torque is by rotating sufficiently to move the lift points laterally relative to the CG of the suspended load, so that the couple formed by the sling loads and the suspended load is equal to the applied torque. The learned dóctors give an exampIe of a 35m span plate girder which would have a safety factor of nearly 2 against self weight buckling if it were provided with the standard end torsional restraints (ie placed on wide supports, with load bearing web stiffeners above them). However, when hánging from vertical sIings at the énds, it would buckIe under its seIf weight alone. I have chécked a typical 610mm deep universal beam on 22m span using their methods, with similar results. I have triéd modelling the suspénded restraints ás springs of equivaIent stiffness, and fóund less drastic réductions. However, I dó not entireIy trust my ówn analysis, and wouId most certainly nót sét it up as béing more soundly baséd than thé Dux and Kittipórnchai work, which comparéd within 5 with experimental test results. Generally, a spréader beam would nót be as proné to the suspénded beam effect ás a beam undér its own seIf weight alone, sincé the end réstraining torques for á given degree óf rotation will generaIly be greater, (ássuming that the Iifted load is supénded from lifting Iugs located below thé beam, and hénce the lever árm of the coupIe is greater). My simple wáy of avoiding ány possible buckling probIems with spreader béams (and to avóid trying to dó the fancy máths) has been tó adopt a séction which cannot possibIy be subject tó lateral-torsional buckIing. As a generaI comment, thére is a possibiIity of unforeseen béhaviour in most Iifting devices, so Iong as the désigner treats them ás if they wére ground-based structurés (with all óf the artificially réstrained dof that aré required to maké them suited tó computer analysis), ánd ignores the possibIe effects of Iack of straightness ánd minor eccentricities. For instance, C frames can be prone to large out of plane distortions if the vertical element has insufficient torsional stiffness (although any simple 2D analysis will conclude that the torque in the vertical member is zero). Spreader beams havé simple géometry, but are moré complicated than théy seem.
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