trb afh70 meeting cold bending small uni virginia
TRANSCRIPT
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Presented by Dr. Cris Moen, Assistant ProfessorCharles E. Via, Jr. Department of
Civil and Environmental EngineeringVirginia Tech
www.moen.cee.vt.edu
TRB AFH70 Committee Meeting
Fabrication and Inspection of Metal Structures
January 24, 2011
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OUTLINE
Introduction
personal background, interest in cold bending fabrication
Examples-cold bending (curving) steel for bridge applications
girders
orthotropic decks
folded plate systems
Cold bending (curving) techniques and mechanics
girders, beams, plates
advantages, challenges, solutions
Research needs
connect the dots between the art of cold bending, materialscience and mechanics
address the presence of cold bending residual stresses
quantify fatigue resistance
develop tools and methods that help fabricators, engineers
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PERSONALINTRODUCTION
Professional experience
J. Muller International, 1997-2002Parsons Transportation Group, 2002-2005
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PERSONALINTRODUCTION
Academic preparation
BSCE, University of Virginia, 1995MSCE, University of Virginia, 1997
PhD, Johns Hopkins University, 2008
Nonlinear FE modeling to collapse,
i.e. simulated tests
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PERSONALINTRODUCTION
Include plastic strainsand residual stresses
from cold bending in FEanalysis
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Cold bending produces residual stresses.
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We have simplified methods for approximating cold
bending residual stress and plastic strain distributions.
Moen, C.D., Igusa, T., and Schafer, B.W. (2008).
"Prediction of Residual Stresses and Strains in Cold-
Formed Steel Members." Thin-Walled Structures, 46(11),
1274-1289.
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OUTLINE
Introduction
personal background, interest in cold bending fabrication
Examples-cold bending (curving) steel for bridge applications
girders
orthotropic decks
folded plate systems
Cold bending (curving) techniques and mechanics
girders, beams, plates
advantages, challenges, solutions
Research needs
connect the dots between the art of cold bending, materialscience and mechanics
address the presence of cold bending residual stresses
quantify fatigue resistance
develop tools and methods that help fabricators, engineers
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COLDBENDINGANDBRIDGES
Bill McEleney, NSBA
Horizontal curves!
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COLDBENDINGANDBRIDGES
Bill McEleney, NSBA
Horizontal curves!
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COLDBENDINGANDBRIDGES
Gergess, N.A., and Sen, R. (2008). !Cold Curving Steel Bridge Girders.!Transportation
Research Board: Journal of the Transportation Research Board, 2081, 165175.
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COLDBENDINGANDBRIDGES
Gergess, N.A., and Sen, R. (2008). !Cold Curving Steel Bridge Girders.!Transportation
Research Board: Journal of the Transportation Research Board, 2081, 165175.
Bend in segments to avoid web stiffeners
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COLDBENDINGANDBRIDGES
Gergess, N.A., and Sen, R. (2008). !Cold Curving Steel Bridge Girders.!TransportationResearch Board: Journal of the Transportation Research Board, 2081, 165175.
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COLDBENDINGANDBRIDGES
Orthotropic bridge decks!
McQuaid, D.L., and Medlock, R.D. (2005). "Constructability Issues in Orthotropic Steel Bridge Deck Bridges."
2005 World Steel Bridge Symposium, American Institute of Steel Construction, Orlando, FL.
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COLDBENDINGANDBRIDGES
Press braking steel plate!
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COLDBENDINGANDBRIDGES
Folded plate bridge systems!
Atorod Azizinamini, Ph.D., P.E.
Highway Bridge Services, L.L.C402-770-6210
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COLDBENDINGANDBRIDGES
Folded plate bridge systems!
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COLDBENDINGANDBRIDGES
Cold-formed light poles!
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OUTLINE
Introduction
personal background, interest in cold bending fabrication
Examples-cold bending (curving) steel for bridge applications
girders
orthotropic decks
folded plate systems
Cold bending (curving) techniques and mechanics
girders, beams, plates
advantages, challenges, solutions
Research needs
connect the dots between the art of cold bending, materialscience and mechanics
address the presence of cold bending residual stresses
quantify fatigue resistance
develop tools and methods that help fabricators, engineers
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BENDINGMETHODS(BEAMS, GIRDERS)
Alwood, T.A. (2006). What Engineers Should Know About Bending Steel. Modern Steel
Construction, American Institute of Steel Construction, May 2006.
Easy way,Hard way,
camber
Repair andstraightening
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ROLLING(COLDBENDING)
Kottler Metal Products
WintersDowney, E. (2006). A Conversation with a Bender!. Modern Steel Construction, July 2008, American
Institute of Steel Construction, Chicago, IL.
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ROLLING(COLDBENDING)
Brady, F.J. (1978). "Determination of minimum radii for cold bending of square and rectangular hollowstructural sections." Programme 11B Final Report, Comit International pour le Dveloppment et l'Etude de
la Construction Tubulaire (CIDECT), Hamilton, Ontario.
Kennedy, J.B., Seddeik, M., and Brady, F. (1986). "Deformations in cold-bent HSS members."Engineering Journal, AISC, Third Quarter, 117-123.
Compared U.S. and European
minimum bending radii limitsfor HSS sections
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INCREMENTALBENDING
Gag pressing is typically used for camber operations.
Bendco
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C
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COLDBENDINGADVANTAGES
Increased yield stress, capacity? Engineers need to be careful about
this one!
. Cold bending residual stresses can counteract increasedyield stress.
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OUTLINE
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OUTLINE
WintersDowney, E. (2006). Curved steel a reference for architects and engineers.American Institute of Steel Construction.