Design of flat space frames generally depends on vertical loads. The increase of vertical loads causes continual member buckling and even collapse of the structure. In this paper, authors propose a structural system in which special members are arraneed for a flat system truss. Installing the special members in the system truss, it becomes a redundant structure under heavy vertical loads. High strength steel budding-restrained members are suitable for the special members in the system truss. This paper studies structural performances of the system using numerical analyses, and also reports exoerimental results for the high strength steel buckling-restrained members.
