Seismic design study of concentrically braced frames with and without buckling-controlled braces

Abstract

Special concentrically braced frames (SCBFs) have become more popular as lateral load resisting systems after disappointing performance of special moment resisting frames (SMRFs) in the 1994 Northridge earthquake. SCBFs dissipate earthquake energy through buckling of compressive braces and yielding of tensile braces. V-type, inverted V-type, and two-story Xbracing are three major categories of SCBF bracing configurations. According to the current design approach implemented in AISC 341-10, beams and columns in SCBFs shall be designed based on the capacity of the braces to keep the beams and columns in the elastic region. However, a limited number of studies have shown that braced-intersected girders in two-story X-braced frames do not always remain elastic during an earthquake, violating current design code assumptions. Inelastic behavior in girders is due to the unsymmetrical cyclic behavior of the braces