SEISMIC BEHAVIOR OF OPEN-WEB TRUSS-MOMENT FRAMES

This paper investigates the behavior and performance of open-web truss-moment framing system under cyclic loading. An open-web truss-moment frame of a four-story building was designed as an ordinary moment resisting frame (OMRF) for this investigation. Three full-scale, half-span subassemblages from this building were tested under severe cyclic deformation to determine their hysteretic behavior. Based on the experimental results, a simple analytical model for inelastic cyclic behavior of open web truss frames was developed. This model was used to analytically evaluate the behavior and performance of the four-story building subjected to several severe earthquake excitations. The system performs poorly because of buckling and fracture of the web members, which led to unstable hysteretic loops.