"Ductility of Column, Wall, and Beams--How Much is Enough?"

Two hypothetical reinforced concrete buildings (one with special moment resisting frames and the other with structural walls) were designed. Using a time-history inelastic behavior approach, both buildings were analyzed. Drifts were determined for these structures when subjected to severe earthquakes similar to those expected in North America. In addition, drifts associated with an analysis based on ground motions measured for the 1985 Mexico City earthquake were also determined. Measured drifts from components detailed under 1990s North American code requirements are compared with calculated building drifts. These comparisons indicate that 1990s code requirements provide significantly more capacity than calculated to be needed for the structures and components considered. Finally, minimum drift requirements for components to be used in ductile frame buildings and in shear wall buildings are suggested.