Statistical Study of Experiments on Welded Beams

Statistical buckling experiments of 34 welded beams for each group of two different lengths are carried out under a concentrated load applied vertically at the midspan of the compressive flange of simply-supported beams. The influences of the variations of the various imperfection parameters on scattered test points of the lateral buckling are examined. The obtained test results are compared with the writers' previous test results of the rolled beams. The main imperfection parameter that highly influences the variation of the ultimate strength of the welded beams is the variable value of the actual full plastic moments, as already mentioned for the rolled beams. The welded beams, however, have a lower ultimate strength in the mean value and large coefficient of variation as compared with the rolled beams. The large variations in the compressive residual stresses and the initial lateral crookednesses in the welded beams may cause the large strength variation in the welded beams.