Performance control for seismic design of moment frames

Performance control (PC) is the important mental task that is or should be the cornerstone of earthquake-resistant structural design. The fundamental notion behind PC is that the seismic structural response is largely a function of design and detailing, rather than conventional analysis. PC is a design strategy in which the strength, stiffness and other characteristics of groups of members are induced in accordance with predetermined objectives rather than investigated with respect to certain design criteria. PC methodology enables engineers to predict and control structural damage at preselected response stages such as at first yield, any fraction of the failure load or allowable drift ratio, etc. PC provides a wealth of important information that may not be readily available through traditional methods of design. The ultimate failure load solutions are “unique” and suitable for plastic design treatment in that they include P-delta and stiffness degradation effects, and satisfy the prescribed yield criteria as well as boundary support and static equilibrium conditions. The proposed procedures for seismic design of moment frames are entirely suitable for manual computations. The paper does not address irregularities in earthquake-resistant moment frames.