This paper discussed strength estimation of steel pipe structure with gusset plate connection in which branch tube axis is eccentric for the main tube axis. The author has carried out experiment and analysis of the member subject models as past researches. On the basis of the past researches, this study carried out experiment and FEM for the 2 layers truss-frame. Based on this study result, the strength evaluation is possible by the technique, which is similar to the member subject model in the frame model. Especially, in case of the slenderness ratio is 30 or less, the negative eccentric joint proves to be an effective measure.
