Optimum Arm Geometry for Ductile Modular Connectors
Publication: Journal of Structural Engineering
Volume 132, Issue 5
Abstract
A cast modular connector (MC) has been developed for use as an energy dissipating detail in seismic-resistant bolted steel moment frames. The MC relies on a series of variable section elements (arms) to minimize plastic strain demand and a stiff end region joined by a base to virtually eliminate bolt prying forces and provide a hysteresis characteristic absent of degradation. The MC was developed through a comprehensive program that included heavy industry partner involvement, analytical research, and experimental verification. This paper describes the portion of the analytical research focused on establishing the optimum geometry for the energy-dissipating arm elements. Key parameters were evaluated through parametric studies using nonlinear (material and geometry) finite element analysis and supported by basic theoretical models. The outcome was a set of optimum geometric ratios covering width reduction, length to thickness, aspect ratio, and fillet radius. A MC prototype was cast on the basis of these recommendations. These prototypes were tested under monotonic and cyclic loading and exhibited remarkable ductility, far exceeding qualifying rotational capacities.
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Acknowledgments
This research was supported by NSF CAREER Award Grant No. NSFCMS-01-96120. Supplemental funds were provided by the American Institute of Steel Construction (AISC) and the Steel Founder’s Society of America (SFSA). The computer laboratory was provided through a grant from Intel, Inc.; finite element software was donated by industry partner Swanson, Inc. (ANSYS). The writers are grateful for this support. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the writer(s) and do not necessarily reflect the views of the National Science Foundation.
References
Aiken, I. D., Nims, D. K., Whittaker, A. S., and James, M. K. (1993). “Testing of passive energy dissipation systems.” Earthquake Spectra, 9(3), 335–370.
American Institute of Steel Construction (AISC). (2001). Load and resistance factor design, 3rd Ed., AISC, Chicago.
American Society of Civil Engineers (ASCE). (1971). “Plastic design in steel.” ASCE-41, New York.
ANSYS version 8. (1999). Elements (00853) and theory reference (00855), SAS IP, Inc., Canonsburg, Pa.
Astaneh, A. (1995). “Post-earthquake stability of steel moment frames with damaged connections.” Connections in Steel Structures III, Behavior, Strength and Design, Proc., 3rd. Int. Workshop, Trento, Italy, 391.
Bergman, D. M., and Goel, S. C. (1987). “Evaluation of cyclic testing of steel-plate devices for added damping and stiffness.” Rep. No. UMCE87-10, Dept. of Civil Engineering, Univ. of Michigan, Ann Arbor, Mich.
Boardman, P. R., Wood, B. J., and Carr, A. J. (1983). “Union house—A cross braced structure with energy dissipators.” Bull. N.Z. Nat. Soc. Earthquake Eng., 16(2), 83–97.
Bursi, O. S., and Jaspart, J. P. (1997). “Benchmarks for finite element modeling of bolted steel connections.” J. Constr. Steel Res., 43(1–3), 17–42.
El-Tawil, S., Vidarsson, E., Mikesell, T., and Kunnath, S. K. (1999). “Inelastic behavior and design of steel panel zones.” J. Struct. Eng., 125(2), 183–193.
Federal Emergency Management Agency (FEMA). (1999). “Interim guidelines advisory No. 2 supplement to FEMA-267.” FEMA-267B. Prepared by the SAC Joint Venture for the Federal Emergency Management Agency, Washington, DC.
Federal Emergency Management Agency (FEMA). (2000). “Recommended seismic design criteria for new steel moment-frame buildings.” FEMA-350, Washington, D.C.
Fleischman, R. B., and Hoskisson, B. (2000). “Development of modular connectors for seismic resistant steel moment frames.” Proc., Structures Congress, ASCE, Philadelphia.
Fleischman, R. B., Sumer, A., and Li, X. (2004). “Development of modular connections for steel special moment frames.” Proc. 21st Structures Congress, ASCE, Reston, Va.
Hoskisson, B. (2000). “Modular connectors for steel seismic resistant moment frames.” M.S. thesis, Notre Dame, Ind.
Lemaitre, J. (1996). A course on damage mechanics, Springer, Berlin.
Rice, J. R., and Tracey, D. M. (1969). “On the ductile enlargement of voids in triaxial stress fields.” J. Mech. Phys. Solids, 17, 201–217.
Roeder, C. W., Knechtel, B., Thomas, E., Vaneaton, A., Leon, R. T., and Preece, F. R. (1996). “Seismic behavior of older steel structures.” J. Struct. Eng., 122(4), 365–373.
Schafer, B. W., Ojdrovic, R. P., and Zarghamee, M. S. (2000). “Triaxiality and fracture of steel moment connections.” J. Struct. Eng., 126(10), 1131–1139.
Steimer, S. F., and Chow, F. L. (1984). “Curved plate energy absorbers for earthquake resistant structures.” Proc., 8WCEE, San Francisco.
Sumer, A., Fleischman, R. B., and Hoskisson, B. (2005a). “Development of a cast modular connector for seismic-resistant steel frames. 1: Prototype development.” Eng. J., in press.
Sumer, A., Fleischman, R. B., and Palmer, N. J. (2005b). “Development of a cast modular connector for seismic-resistant steel frames. 2: Experimental verification.” Eng. J., in press.
Swanson, J. A., and Leon, R. T. (2000). “Bolted steel connections: Tests on T-stub components.” J. Struct. Eng., 126(1), 50–56.
Varicast Steel Casting (2003). Mechanical Testing Rep., Varicast Steel Casting, Portland, Ore.
Whittaker, A. S., Bertero, V. V., Thompson, C. L., and Alonso, L. J. (1989). “Earthquake simulator testing of steel plate added damping and stiffness elements.” Report No. UCB/EERC-89/02, Earthquake Engineering Research Center, Univ. of California at Berkeley, Berkeley, Calif.
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© 2006 ASCE.
History
Received: Sep 8, 2003
Accepted: Oct 17, 2005
Published online: May 1, 2006
Published in print: May 2006
Notes
Note. Associate Editor: Brian Uy
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