Structures have traditionally been designed for earthquake resistance by providing a sufficient strength level to resist a prescribed static lateral load. Though previous codes only defined the required lateral loading, there was an implicit assumption that a certain amount of post-yield deformability would be available within the structure while a yield level resisting capacity was maintained. Recent codes have specifically addressed the need for ductility to be provided during the design in conjunction with the specified design loading. It is unclear, however, what level of ductility might actually be available in precast concrete construction. These recent changes have left producers of precast components pondering the problem of how to provide a usable product and caused design engineers to become reluctant to design precast structures in seismic regions.
