Spacial Truss Moment Frame Component Test 13 - 2C8x18.75

Specimen 13, made of double channels C8x18.75 was tested under cyclic loading. The test setup represents the chord members in the special segment of a prototype STMF. The specimen was welded to a gusset plate and the reaction column. Part of the gusset plate was not welded to the specimen in order for the specimen to slide while displace cyclically. This part of the gusset plate proved to eliminate lateral torsional buckling of double channels. Horizontal stitches were welded on the top and bottom flanges near the gusset plate to prevent separation of the channels. The specimen sustained its strength under cyclic loading until failed after several cycles of the maximum stroke limit of the actuator. This limit, 4.92 in., was equivalent to over 2.7% story drift or 9% member drift. Bulging occurred but not severely due to small h/t ratio. Major loss of strength was induced by fracture of the specimen. Hysteretic behavior of the specimen was stable and ductile. As a result, this member will be used as chord members in the full scale specimen to be tested at MAST Laboratory, the University of Minnesota.