Special Truss Moment Frame Component Test 10 - 2C12x20.7

Special truss moment frame component test 10, made of double channels 2-C12x20.7, was tested under cyclic loading. The test setup was a representative of half of the chord in the special segment of the prototype special truss moment frame. To simplify the detailing, 2 pair of stiffeners were used instead of 3 pairs used in experiment 4. The second pair of the stiffeners were placed in the middle between the end of the horizontal welds and the edge of the first horizontal stitches at 3.5 in. spacing. The first pair of stiffeners were placed at 5 in. away from the second pairs to reduce the restraint of the flanges . Moreover, to eliminate restraint induced by the vertical members which were welded to the bottom flanges of the chord members in experiment 9, the vertical members were not welded to the chord members in this experiment. The specimen exhibited stable and ductile hysteretic behavior up to approximately 2.75% story drift or 8.5% member drift. Its behavior is comparable to experiment 4 result. Similarly to experiment 4, minor flange local buckling, bulging, and weld crack were observed at 1.5% story drift. Flange and web local buckling, bulging, and weld crack progressed as the test continued and strength started to slightly drop starting at 2.38% story drift. Bulging was confined within the space between the stiffeners while flange local buckling occurred at several spots. The hysteretic behavior of the specimen was stable and ductile. The test was terminated at 2.75% story drift or 8.67% member drift when the web and the flange of the west channel fractured.