In designing adequate ductility into a frame structure to resist earthquake forces, the portion of the procedure which has the least satisfactory theoretical and experimental basis is the strictly design part. This is the section in which the designer, having assessed the ductility demands of the various members of the frame, proceeds to decide on the concrete dimensions and reinforcement pattern which will satisfy these demands. The reasons for the shortcomings are fairly obvious. Unlike frame analysis and frame response, which can be dealt with as tidy applied mechanics problems, investigation of the design problems requires research workers with an extensive design background, and an awareness of all the design criteria which have to be satisfied. Unfortunately, such research workers are rare, and consequently insufficient research has been carried out. What research has been done has obviously not been planned with a
view to obtaining information that can be used in design.