Page 224 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

Brockenbrough_Ch05.qxd 9/29/05 5:12 PM Page 5.4

CRITERIA FOR BUILDING DESIGN

5.4 CHAPTER FIVE

TABLE 5.1 Limiting Width–Thickness Ratios for Compression Elements
Limiting width–thickness ratios
Width–
thickness λ ρ λ r
Case Description of element ratio (compact) (noncompact) Example
Unstiffened elements
/
/
.
1 Flexure in flanges of rolled b/t 038 EF y 10 EF y
.
I-shaped sections and
channels in flexure

.
2 Flexure in flanges of doubly b/t 038 EF y 095 kE /F L
.
/
c
and singly symmetric [a] [b]
I-shaped built-up sections

3 Uniform compression in b/t NA 056 EF y
/
.
flanges of rolled I-shaped
sections, plates projecting
from rolled I-shaped
sections; outstanding legs
of pairs of angles in
continuous contact, and
flanges of channels
.
4 Uniform compression in b/t NA 064 kE /F y
c
flanges of built-up I-shaped [a]
sections and plates or angle
legs projecting from
built-up I-shaped sections

5 Uniform compression in legs b/t NA 045 EF y
/
.
of single angles, legs of
double angles with
separators, and all other
unstiffened elements
/
6 Flexure in legs of b/t 054 EF y 091 EF y
/
.
.
single angles
(Continued)

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