Seismic Behavior of SCBFs with Reduced Braced Span

In design of concentrically braced frames (CBFs), architectural restrictions may cause disruptions in continuous braced-spans. A practical solution for this problem is the use of reduced-braced-span (RBS) in the first-story in which the width of the bracing panel is reduced using an added column between theboundary columns of the panel. The aim of this study is to evaluate and validate design criteria of the boundary columns for common and RBS-SCBFs by means of nonlinear dynamic analysis. Results show that the design criteria proposed by codes for low-rise SCBFs are not appropriate; furthermore the added column in such RBS-SCBFs should be checked for higher axial demands.

Keywords:

Concentrically braced frame , Seismic design , Overstrength factor , RBS system , Seismic demand