ABSTRACT
Performance-based design was originally developed for structures that are an exception to the building code through an alternative, nonprescriptive approach to design with the methodology confirming code equivalence. These structures typically complied with the general requirements of the building code, with the exception of height limits described for particular seismic force-resisting systems, or for seismic force-resisting systems not specifically described in the code. For instance, concrete structures of various mass and stiffness characteristics over 49 m (160 ft) tall located in areas of high seismicity require a dual structural system composed of a shear wall core and moment-resisting frame to meet the prescriptive intent of the building code. Because of increased cost, increased construction time, and architectural impacts, many have designed and successfully built these structures without the frame by proving code equivalency through performance-based design methods.
