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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.