TY - JOUR
T1 - Seismic performance of chevron-configured special concentrically braced frames with yielding beams
AU - Asada, Hayato
AU - Sen, Andrew D.
AU - Li, Tao
AU - Berman, Jeffrey W.
AU - Lehman, Dawn E.
AU - Roeder, Charles W.
N1 - Funding Information:
This research was funded by the American Institute of Steel Construction. Mr Tom Schlafly was the program manager for this work. James Malley, Rafael Sabelli, and Tom Sabol served as technical advisors to the research team. The financial support and technical advice are greatly appreciated and gratefully acknowledged. The first author gratefully acknowledges the financial support from Japan Society for the Promotion of Science (R2904) for collaborating with the research team at University of Washington.
Publisher Copyright:
© 2020 John Wiley & Sons, Ltd.
PY - 2020/12/1
Y1 - 2020/12/1
N2 - Current seismic design requirements for special concentrically braced frames (SCBFs) in chevron configurations require that the beams supporting the braces be designed to resist the demands resulting from the simultaneous yielding of the tension brace and degraded, post-buckling strength of the compression brace. Recent research, including large-scale experiments and detailed finite-element analyses, has demonstrated that limited beam yielding is not detrimental to chevron braced frame behavior and actually increases the story drift at which the braces fracture. These findings have resulted in new expressions for computing beam demands in chevron SCBFs that reduce the demand in the tension brace to be equal to the expected compressive capacity at buckling of the compression brace. In turn, the resultant force on the beam is reduced as is the required size of the beam. Further study was undertaken to investigate the seismic performance of buildings with SCBFs, including chevron SCBFs with and without yielding beams and X-braced frames. Prototype three- and nine-story braced frames were designed using all three framing systems, that is, chevron, chevron with yielding beams, and X SCBFs, resulting in six building frames. The nonlinear dynamic response was studied for ground motions simulating two different seismic hazard levels. The results were used to characterize the seismic performance in terms of the probability of salient damage states including brace fracture, beam vertical deformation, and collapse. The results demonstrate that the seismic performance of chevron SCBFs with limited beam yielding performs as well as or better than the conventionally designed chevron and X SCBFs.
AB - Current seismic design requirements for special concentrically braced frames (SCBFs) in chevron configurations require that the beams supporting the braces be designed to resist the demands resulting from the simultaneous yielding of the tension brace and degraded, post-buckling strength of the compression brace. Recent research, including large-scale experiments and detailed finite-element analyses, has demonstrated that limited beam yielding is not detrimental to chevron braced frame behavior and actually increases the story drift at which the braces fracture. These findings have resulted in new expressions for computing beam demands in chevron SCBFs that reduce the demand in the tension brace to be equal to the expected compressive capacity at buckling of the compression brace. In turn, the resultant force on the beam is reduced as is the required size of the beam. Further study was undertaken to investigate the seismic performance of buildings with SCBFs, including chevron SCBFs with and without yielding beams and X-braced frames. Prototype three- and nine-story braced frames were designed using all three framing systems, that is, chevron, chevron with yielding beams, and X SCBFs, resulting in six building frames. The nonlinear dynamic response was studied for ground motions simulating two different seismic hazard levels. The results were used to characterize the seismic performance in terms of the probability of salient damage states including brace fracture, beam vertical deformation, and collapse. The results demonstrate that the seismic performance of chevron SCBFs with limited beam yielding performs as well as or better than the conventionally designed chevron and X SCBFs.
KW - chevron braced frames
KW - performance-based design
KW - seismic performance
KW - special concentrically braced frames
KW - steel braced frames
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U2 - 10.1002/eqe.3320
DO - 10.1002/eqe.3320
M3 - Article
AN - SCOPUS:85088235259
VL - 49
SP - 1619
EP - 1639
JO - Earthquake Engineering and Structural Dynamics
JF - Earthquake Engineering and Structural Dynamics
SN - 0098-8847
IS - 15
ER -