SPECIAL TRUSS MOMENT FRAMES WITH VIERENDEEL MIDDLE PANEL

This paper presents an alternative configuration of the special truss segment in special truss moment frames (STMF). The study is an extension of a previous study by Goer and Itani at the University of Michigan in which an integrated analytical and experimental programme was conducted on this system with X-diagonal middle segments for the trusses. The system showed excellent improvement in behaviour over the conventional truss moment frames as used in current practice. However, the X-diagonals in the middle panels may cause undesirable obstruction for ductwork and piping systems in some situations. A Vierendeel middle segment (no X-diagonals) is proposed in this paper for STMF; th us, the wide opening can be utilized for ductwork and piping. The shear caused by lateral forces in the open panel of the trusses is resisted solely by the chord members. A four-storey study building, which had been designed using X-diagonal configuration in the previous study, was redesigned using the proposed configuration. Excellent inelastic response is obtained through stable and 'full' hysteretic loops. Minor reductions in the stiffness and strength of the system resulted due to the absence of X-diagonals.