Seismic performance of steel moment frames with reduced beam sections

This paper presents an investigation on the seismic performance of steel moment-resisting frames with reduced beam sections (RBS), and addresses the design issues related to the RBS frames. Nonlinear static and time history analyses of eight frames (three- and ten-story steel moment frames with different RBS configurations are conducted. The 1940 Imperial Valley (El Centro station, 0.32 g PGA) and the 1994 Northridge (Newhall station, 0.59 g PGA) ground motions factored to 0.3 g and 0.6 g are used in the time-history analyses. Global and local performances of the frames are discussed in terms of plastic deformation, inelastic drift ratio, as well as strength demand. The quantitative indices, such as flange reducing rate and location of the RBS, are recommended for seismic design practice.