Component testing and multi-level seismic design of steel braced frames with high post-yielding stiffness and two-phase yielding

Using induction heat (IH) treatment to locally transform one half of a steel brace section high-strength as well inducing intentional eccentricity along the length has been experimentally proven increase limited post-yielding stiffness exhibited by conventional braces. This paper develops multi-level seismic design method for intentionally eccentric IH-treated braced frames (IH-FIEB) support their implementation in building structures. More specifically, experimental results on cyclic behaviour braces with (IH-BIEs) are presented giving an emphasis quantifying member's resistance local buckling and fracture initiation. A theoretical model is developed force-deformation relationship bracing system which validated test obtained from parametric finite element analysis study. On basis model, expressions that describe mechanical two-phase yielding controlled alternated flexural-axial developed. The high controllability response through provide capability satisfying multiple strength performance objectives simultaneously. Time-history under three hazard levels demonstrate IH-FIEBs assure more uniform overstrength plastic engagement between each story than frames. IH-BIEs smoothly transition into post-buckling engage plastically at low drift demands, while forces close values expected procedure. significant reduction residual deformation observed intensity indicating may be able reduce post-hazard damage compared