Design Optimization of Steel Moment Frames Under Extreme Earthquake Loading

Abstract

ABSTRACT:The paper presents a design optimization method for steel moment frames under extreme earthquake loading. Seismic responses of the structures are evaluated using a nonlinear pushover analysis procedure. Minimum structural cost and uniform heightwise ductility demand are identified as the design objectives. Roof and interstory drifts are taken as design constraints. Strong-column weak-beam requirement is treated as additional constraints for special moment frames. The sensitivities of inelastic displacements are employed to explicitly formulate the objective functions and constraints in terms of member sizing variables. A dual method is then used to search for an optimal design solution. The proposed design methodology is illustrated for a nine-story moment frame example.