DUCTILITY AND OVERSTRENGTH IN SEISMIC DESIGN OF REINFORCED-CONCRETE STRUCTURES

The paper first reviews the different approaches taken by codes of pra ctice in their treatment of ductility demand by the use of force modif ication factors. The way in which structural overstrength affects stru ctural response and the factors influencing overstrength are discussed . Nonlinear analyses of reinforced concrete structures, designed by th e Canadian codes, demonstrate the significance of structural overstren gth on the ability of the structures to resist lateral load without co llapse. The manner in which structural overstrength can be accounted f or in the design of reinforced concrete structures is presented.