Comparison on seismic behavior of concentrically braced frames designed as Per TSC2007 and TSC2019

Concentrically braced frames (CBFs) indicating high elastic stiffness are one of the most preffered lateral load resisting systems in seismic regions. CBFs are composed of columns, beams and braces which are concentrically connected the beams or beam to column joints. During an earthquake event, seismic performance of the braces subjected to cyclic and reversible axial tension and compression loading determines the ductility capacity of the entire structure. Turkish Seismic Code 2019 (TSC 2019), which has became valid in 2019, mandates design of the Special Concentrically Braced Frames (SCBFs) in accordance with capacity of the axial tension and compression capacity. In this study, firstly, SCBFs having different number of storeys were designed as per Turkish Steel Code 2018 (TSC 2018) as well as TSC 2007 and then these braced frames were revised in accordance with TSC 2019. By using OPENSEES software program, 528 nonlinear time history analysis were conducted on the designed archtypes with 3, 6, 9 storeys under 44 far field gound motions defined in FEMA P695. In the light of the anaysis results, interstory drift ratios, residual lateral displacements, maximum storey accelerations and velocities, brace ductility demands and brace outof-plane displacements were compared. According to obtained analysis, TSC 2019 indicated more reliable seismic response for inverted V braced SCBF whereas TSC 2007 showed more reliable seismic behavior for split X braced SCBF in spite of lesser steel material used.