This study is planed to clarify the seismic performance for existing steel structure using rolled-H section members. The cyclic loading tests with increasing amplitude were conducted on five welded beam-column subassemblages having a T-shape. The test parameters were the type of the column members and the beam-to-column connections. From the results of these tests, the hysteresis characteristics, the skeleton curve, the rotation rigidity, the yield strength and the ultimate strength are clarified. The vertical triangular haunch plates have great influence on the yield strength and the failure mode.
