Performance -based design of steel moment frames using target drift and yield mechanism.

A performance-based seismic design procedure for steel moment frames based on pre-selected yield mechanism and target drift is proposed in this paper. The design base shear is derived from a modified energy balance equation incorporating the concept of seismic force reduction factor and the displacement amplification factor. A new seismic lateral force distribution based on nonlinear dynamic analyses is also presented. Three steel moment frames were designed using the proposed lateral force distribution and the performance plastic design methodology with specified pre-selected target drifts. The inelastic seismic behaviors of the three frames were studied through nonlinear static and dynamic analyses. The results showed that all three frames performed very well under design level ground motions; in particular, all frames exhibited expected yield mechanism with story drifts within the target limit. That is, the structural performance can be well predicted and “controlled” by employing the proposed performance-based design procedure.