Resumen:
Basic formulations to estimate critical load for shear buckling of flat plates were reviewed and applied to two simple situations. Then two configurations of I beams were built, with 3 and 5 vertical stiffeners, with the portions of its webs as the panels previously analyzed. A total of four specimens were built, 100 long, 35 in height and 15 cm in flange width; the webs were 1.5 and the flanges, 3.0 mm in thickness, to avoid compressive buckling of the flanges. Buckling of the panels was observed with the classical inclined pattern; in the second specimen of the first configuration, and both specimens of the second configuration, some weld points failed, with high noise, and a reduction in resistance. Registered buckling vertical loads were: 1708 and 1337 for the first, and 1582 and 1337 kg, for the second configuration. Finally, using SAP2000 computer program, critical loads and corresponding mode shapes were calculated using two numeric models, using 6912 and 7488 Shell elements. Applying load in eight central nodes, 1155 and 2317 kg were necessary to reach the first mode shape of each configuration. In the three types of calculations, the buckling results were similar, that is the laterally deformed panel follow the direction of the main diagonal; the analytical with simply supported edges and numerical results for the critical load show good agreement, while the experimental values, from the second configuration are below the expected values.
