TESTS OF PROFILED STEEL DECKS WITH FLAT-HAT STIFFENERS

The tests described in this paper are the second in a program carried out to determine the effectiveness of intermediate stiffeners in contr olling the buckling modes of profiled steel decks. A series of specime ns with ''flat-hat'' intermediate stiffeners were brake-pressed to des igns that were chosen to ensure that the primary buckling mode took pl ace in the elastic range and was not affected by plasticity. The speci mens were loaded in pure bending, resulting in various buckling wavefo rms prior to ultimate failure through a plastic collapse mechanism. Th e experimentally determined buckling stresses are compared with studie s performed using a computer analysis based on the finite-strip method . The existing design procedure for local buckling in Australian Stand ard AS1538-1988 and various methods involving distortional buckling ar e compared with the test results. A method of design accounting for th e interaction of buckling modes and its effect on the ultimate moment capacity is proposed and compared with the test results.