introduction to coldformed steel

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introduction to cold-formed steel

• a short course in cold-formed steel behavior,
  analysis, and design
• April 2001

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Outline

• Forming and Shapes
• Applications
• Basic Behavior
• Current Design
• Advanced Behavior
• Future Design

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Strength Through Shape
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Cold-Formed Steel?

• Structural shapes folded from sheet steel
• Thickness 1mm
• Used widely in modern day applications
• decking
• racks
• wall studs (replacement for wood)

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First Generation Shapes
Press brake
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Second Generation Shapes
Roll formed
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CFS Rack Structures
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CFS Framing
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Outline

• Forming and Shapes
• Applications
• Basic Behavior
• Current Design
• Advanced Behavior
• Future Design

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Tension
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Tension Member
tension member design similar to
hot-rolledyield in the gross, fracture in the
net, bearing, bolt (screw) shear material is
just thinner!
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Compression local buckling
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Bendinglocal buckling
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Bending local buckling collapse
example from the JHU structures lab.
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Bendinglocal buckling
k4.0
k0.425
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Other behavioral complications

• Post-buckling and reserve capacity
• Cross-section variety
• Interaction

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Elastic post-buckling
load
flat plate in compression
typical compact hot-rolled steel column
Pcr
cylinder (coke can) in compression
out of plane deformation
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Winter Post-buckling model
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Outline

• Forming and Shapes
• Applications
• Basic Behavior
• Current Design
• Advanced Behavior
• Future Design