Limiting Width-to-Thickness Ratios for Compression Elements for Moderately Ductile Members per AISC 341-16 with ideCAD

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Last updated: Sept 06, 2023 by oğuzcan hadim
3 min read

How does ideCAD control Width-to-Thickness Ratios according to AISC 341-16?

  • Column, beam and brace members of frames, that resists moderate ductility level loads are automatically controlled and reported according to Table D1.1.

Symbols

Fy = Specified minimum yield stress
Ry = Ratio of the expected yield stress to the specified minimum yield stress, Fy
λhd= Limiting slenderness parameter for highly ductile compression elements
λmd = Limiting slenderness parameter for moderately ductile compression elements
E= Modulus of elasticity of steel = 29,000 ksi (200 000 MPa)

Table D1.1 Limiting Width-to-Thickness Ratios for Compression Elements for Moderately Ductile and Highly Ductile Members

  • For horizontal load-bearing system elements to perform sufficient plastic deformation under earthquake effects without local buckling, the width-to-thickness ratios of compression elements must meet the conditions given in Table D1.1.

  • The width-to-thickness ratios of steel elements are automatically controlled and reported with steel elements reports according to Table D1.1.

Limiting Width-to-Thickness Ratios for Compression Elements for Moderately Ductile and Highly Ductile Members

Limiting Width-to-Thickness Ratios for Compression Elements for Moderately Ductile and Highly Ductile Members

Description of Element

Width-to- Thickness Ratio

Limiting Width-to-Thickness Ratio

Example

λhd
Highly Ductile Members

λmd
Moderately Ductile Members

Flanges of rolled or built-up I-shaped sections, channels and tees; legs of single angles or double-angle members with separators; outstanding legs of pairs of angles in continuous contact

 

 

 

b/t

 

 

 

 

 

 

 

Flanges of H-pile sections per Section D4

 

b/t

 

not applicable

 

Stems of tees

d/t

Walls of rectangular HSS used as diagonal braces

b/t

Flanges of boxed I-shaped sections

b/t

Side plates of boxed I-shaped sections and walls of built-up box shapes used as diagonal braces

h/t

Flanges of built up box shapes used as link beams

b/t

Webs of rolled or built-up I shaped sections and channels used as diagonal braces

hw/t

 

Where used in beams or columns as flanges in uniform compression due to axial, flexure, or combined axial and flexure:

  1. Walls of rectangular HSS

  2. Flanges and side plates of boxed I-shaped sections, webs and flanges of built-up box shapes

 

 

 

 

 

 

b/t

 

 

h/t

 

 

 

 

 

 

 

 

 

 

 

Where used in beams, columns, or links, as webs in flexure, or combined axial and flexure:

  1. Webs of rolled or built-up I shaped sections or channels [b]

  2. Side plates of boxed I-shaped sections

  3. Webs of built up box sections

 

 

 

 

h/tw

 

 

h/t

 

 

h/t

For Ca ≤ 0.114

For Ca > 0.114

where


For Ca ≤ 0.114

For Ca > 0.114

where


 

Webs of built-up box sections used as EBF links

h/t

 

Webs of H-Pile sections

h/tw

 

not applicable

Walls of round HSS

D/t

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Width-to-Thickness Ratios for IMF per AISC 341-16 with ideCAD

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