Direct Displacement-Based Design Versus Performance-Based Plastic Design Approaches for Steel Moment-Resisting Frames.

The aim of this study is to compare direct displacement-based design (DDBD) and performance-based plastic design (PBPD) in order to identify more effective design approach for steel moment-resisting frames. To this end, three steel moment-resisting frames with different heights of 4, 8 and 12 stories have been designed using DDBD and PBPD. Although DDBD obtains higher design base shear in comparison with PBPD in high-rise buildings, DDBD leads a lighter structure than PBPD. This is because of significant difference of these design approaches in the design base shear distribution at the height of structure. DDBD approach distributes the base shear such that the design story shear at upper stories is significantly lower. Because of this distribution model, DDBD leads formation of plastic hinges at columns of upper stories, whereas total plastic hinges have been formed at desirable locations in PBPD. To validate the achievement of design performance level, nonlinear time history analysis of steel moment-resisting frames is performed under twenty-two earthquake records. It can be found from the results that PBPD is the efficient design approach for both low-rise and high-rise steel moment frames, whereas the effectiveness of DDBD approach is questioned by increasing the number of stories of structure. [ABSTRACT FROM AUTHOR]