Steel brace section dimensions do not conform to Width-to-Thickness Ratios.

This message is created by specifying the element name and floor on which it is located at the beginning of the report.

For example,

SBR001 BASE STORY Section dimensions do not conform to Width-to-Thickness Ratios.

Width-to-thickness ratios of highly ductile and moderately ductile braces are checked per AISC 341-16 Table D1.1 and TBDY Chapter 9. Limit values of Width-to-thickness ratios λ _hd or λ _md are given in AISC 341-16 Table D1.1.

For detailed information, you can review the titles below.

Concentrically Braced Frames (CBF) per AISC 341-16 §F

Solutions:

The cross-section of the steel element whose name and floor are given can be changed.
Steel beam cross-section selection can be made to reduce the header width/thickness or body height/thickness ratio.
If possible, a moderate ductility level can be selected.

AISC 341-16 Table D1.1 is given below.

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
Description of Element	Width-to- Thickness Ratio	λ_hd Highly Ductile Members	λ_md Moderately Ductile Members	Example
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	h_w/t
Where used in beams or columns as flanges in uniform compression due to axial, flexure, or combined axial and flexure: Walls of rectangular HSS 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: Webs of rolled or built-up I shaped sections or channels [b] Side plates of boxed I-shaped sections Webs of built up box sections	h/t_w h/t h/t	For C_a ≤ 0.114 For C_a > 0.114 where	For C_a ≤ 0.114 For C_a > 0.114 where
Webs of built-up box sections used as EBF links	h/t
Webs of H-Pile sections	h/t_w	not applicable
Walls of round HSS	D/t