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

How does ideCAD control Width-to-Thickness Ratios for special moment frames according to AISC 341-16?


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


The structural frame members, such as columns and beams with highly ductile members, are controlled according to Table D1.1 and reported in steel column and steel beam reports.



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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