Inelastic buckling of torsionally braced I-girders under uniform bending,II: Experimental study

This paper presents a series of experimental test results on the inelastic buckling of torsionally braced I-girder system under uniform bending. In order to confirm the numerical study results on the design criteria for torsional diaphragm braces which are presented through the companion paper, a test program was performed. Totally four sets of test models that form 2-girder systems interconnected with I-shaped crossbeams were fabricated by using SM570-TMC steel. Pure bending test was conducted on each test model up to the ultimate bending capacity. Then, numerical analyses were performed for a comparative study. The bending resistance capacities of the test girders were evaluated by using the Eurocode 3 and the AASHTO LRFD specifications to compare with the test results. From the comparative studies, the torsional bracing requirements were experimentally proved for the inelastic buckling range approaching the compact unbraced length limit. Finally, the validity of the proposed design equations including the current design provisions is discussed.