energy-based design of knee-element connection frames (kcfs) in pipe racks

This paper studies the application of knee-element connection frames (kcfs) as a seismic load resisting systems for pipe racks. this structural system only uses simple connections and provides a zonular rigid connection compared to the concentrated rigid connections used in moment-resisting frames (mrfs). kcfs are of particular advantage over other load-resisting systems in petrochemical structures, such as pipe racks, due to their ample access for maintenance and enhanced structural performance. in the past two decades, extensive research has been conducted to evaluate kcfs seismic performance and to determine the most efficient configurations. this study utilizes an energy-based approach (energy balance concept) to design pipe racks. this design approach is eventually implemented with modeling a pipe rack structure in sap2000 and non-linear static analysis is performed to corroborate the design concept and assumptions. the results demonstrate an acceptable correlation between the assumed general yield mechanism and the real structure behavior. plastic hinges are spread throughout the structure height which implies a desirable input energy consumption.