Ductility and overstrength in seismic design of reinforced concrete structures
The paper first reviews the different approaches taken by codes of practice in their treatment of ductility demand by the use of force modification factors. The way in which structural overstrength affects structural response and the factors influencing overstrength are discussed. Nonlinear analyses of reinforced concrete structures, designed by the Canadian codes, demonstrate the significance of structural overstrength on the ability of the structures to resist lateral load without collapse. The manner in which structural overstrength can be accounted for in the design of reinforced concrete structures is presented. Key words: seismic design, detailing, reinforced concrete, ductility, overstrength, base shear.