Cyclic Testing of a Buckling Restrained Braced Frame with Unconstrained Gusset Connections
Publication: Journal of Structural Engineering
Volume 135, Issue 12
Abstract
Buckling restrained braces are intended to yield in both axial tension and compression. The gusset plates connecting them to the adjacent beams and columns are thick and often stiffened to prevent buckling, and as a result increase the stiffness of the beam-to-column connection substantially. The increased stiffness of the beam-to-column connection negatively impacts the seismic performance of the system by: increasing the portion of the base shear force that is resisted by the frame relative to that resisted by the braces; increasing the maximum base shear force that the system is subjected to for a given earthquake motion; and transferring moment to the braces for which they were not designed. Further, failure of gusset welds partly due to the opening and closing of the beam-to-column joint has been observed in recent experiments. To mitigate these effects and increase the efficiency of buckling restrained braced frames, a novel connection where the gusset is only connected to the beam and is offset from the column face is proposed and tested in a three-story frame under quasistatic loading. The connection is shown to accommodate frame drifts as large as 3% and satisfy the buckling restrained brace performance requirements of the 2005 AISC Seismic Provisions for Steel Buildings. Additionally, the portion of base shear force resisted by the braces relative to that resisted by the surrounding frame is shown to be consistent with design assumptions. This connection configuration could be particularly useful for retrofit of seismically deficient moment resisting frames.
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Acknowledgments
This work was supported in part by the Earthquake Engineering Research Centers Program of the National Science Foundation under Award No. NSFECC-9701471 to the Multidisciplinary Center for Earthquake Engineering Research. However, any opinions, findings, conclusions, and recommendations presented in this paper are those of the authors and do not necessarily reflect the views of the sponsors.
References
AISC. (2005a). “Seismic provisions for structural steel buildings.” ANSI/AISC 341-05 and ANSI/AISC 341s1-05, Chicago.
AISC. (2005b). “Specifications for structural steel buildings.” ANSI/AISC 360-05, Chicago.
Astaneh-Asl, A. (1998). “Seismic behavior and design of gusset plates.” Steel tips, Structural Steel Educational Council, Moraga, Calif.
Black, C. J., Makris, N., and Aiken, I. D. (2004). “Component testing, seismic evaluation and characterization of buckling-restrained braces.” J. Struct. Eng., 130(6), 880–894.
Christopulos, A., Lehman, D., and Roeder, C. W. (2006). “Seismic performance of special concentrically braced frames with buckling restrained braces.” Proc., 8th National Conf. on Earthquake Engineering at the 100th Anniversary Earthquake Conf., EERI, Oakland, Calif.
Computers and Structures Inc. (2004). Structural Analysis Program, SAP-2000NL Version 9.2.0: Integrated Finite Element Analysis and Design of Structures, Computers and Structures Inc., Berkeley, Calif.
Fahnestock, L. A., Ricles, J. M., and Sause, R. (2007). “Experimental evaluation of a large-scale buckling-restrained braced frame.” J. Struct. Eng., 133(9), 1205–1214.
Federal Emergency Management Agency. (2000a). “State of the art report on systems performance of steel moment frames subject to earthquake ground shaking.” Rep. No. FEMA 355C, FEMA, Washington, D.C.
Federal Emergency Management Agency. (2000b). “Steel moment frame buildings: Design criteria for new buildings.” Rep. No. FEMA 350, FEMA, Washington, D.C.
Iwata, M., Kato, T., and Wada, A. (2000) “Buckling-restrained braces as hysteretic dampers.” Behaviour of steel structures in seismic areas: STESSA 2000, Balkema, Rotterdam, The Netherlands, 33–38.
Lopez, W. A., Gwie, D. S., Lauck, T. W., and Saunders, C. W. (2004). “Structural design and experimental verification of a buckling-restrained braced frame system.” Eng. J., 4, 177–186.
Mahin, S., Uriz, P., Aiken, I., Field, C., and Ko, E. (2004). “Seismic performance of buckling restrained braced frame systems.” Proc., 13th World Conf. on Earthquake Engineering, Int. Association of Earthquake Engineering (IAEE), Tokyo.
Sabelli, R. (2004). “Recommended provisions for buckling-restrained braced frames.” Eng. J., 4, 155–175.
Tremblay, R., Bolduc, P., Neville, R., and DeVall, R. (2006). “Seismic testing and performance of buckling-restrained bracing systems.” Can. J. Civ. Eng., 33(2), 183–206.
Tsai, K. -C., Hsiao, P. -C., Lin, S. -L., and Lin, K. -C. (2006). “Overview of the hybrid tests of a full scale 3-bay 3-story CFT/BRB frame.” Proc., 4th Int. Symp. on Steel Structures (ISSS ’06), Korean Steel Structures Association (KSSC), Seoul, Korea, 73–84.
Tsai, K. -C., Weng, Y. -T., Lin, M. -L., Chen, C. -H., Lai, J. -W., and Hsiao, P. -C. (2003). “Pseudo dynamic tests of a full-scale CFT/BRB composite frame: Displacement based seismic design and response evaluations.” Proc., Int. Workshop on Steel and Concrete Composite Construction (IWSCCC-2003), National Center for Research in Earthquake Engineering, Taipei, Taiwan, 165–176.
Vargas, R., and Bruneau, M. (2009a). “Analytical response and design of buildings with metallic structural fuses: I.” J. Struct. Eng., 135(4), 386–393.
Vargas, R., and Bruneau, M. (2009b). “Experimental response of buildings designed with metallic structural fuses: II.” J. Struct. Eng., 135(4), 394–403.
Wada, A., Connor, J. J., Kawai, H., Iwata, M., and Watanabe, A. (1992). “Damage tolerant structures.” Proc., 5th U.S.-Japan Workshop on the Improvement of Structural Design and Construction Practices, Applied Technology Council, Redwood City, Calif., 27–39.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 135 • Issue 12 • December 2009
Pages: 1499 - 1510
Copyright
© 2009 ASCE.
History
Received: Oct 6, 2008
Accepted: May 10, 2009
Published online: Jun 10, 2009
Published in print: Dec 2009
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