11. Direct Damage-Controlled Design

The direct damage controlled design method for seismic design of plane steel moment resisting framed structures is described. This method in its dynamic or static (pushover) version is capable of controlling damage at all levels of performance. The proposed method can be used not only for designing a structure for a given seismic load and desired level of damage, but also for determining damage in a designed structure locally or globally due to any seismic load or evaluating the maximum seismic load a structure can undertake for a desired level of damage. The above are accomplished by introducing a new seismic damage index and constructing appropriate damage performance levels. The seismic damage index takes into account axial force-bending moment interaction, strength and stiffness deterioration and low cycle fatigue. The damage performance levels are established with the aid of extensive parametric studies on a large number of frames under a large number of seismic motions in conjunction with the above damage index for damage evaluation. Numerical examples are provided to illustrate the proposed method in its dynamic and static versions and demonstrate its merits against other methods of seismic design.