# Steel Members with Slender Elements per AISC 360-16 with ideCAD

How does ideCAD calculate steel compression strength with slender elements according to AISC 360-16?

• The compression strength of steel elements is calculated automatically according to AISC 360-16.

• The nominal compressive strength limit states of flexural buckling, torsional buckling, and flexural-torsional buckling are controlled automatically according to AISC 360-16.

Symbols

Ag : Gross cross-sectional area of member
Ae : Effective area
be : The effective width
c1, c2 : Effective width imperfection adjustment factor determined from Table E7.1
D : outside diameter of round HSS
Fcr : Critical stress
Fe : Elastic buckling stress determined according to Equation E3-4,
Fel : Eelastic local buckling stress determined according to Equation E7-5
Fy : Specified minimum yield stress of the type of steel being used,
K : Effective length factor
L: Laterally unbraced length of the member
Lc : Effective length of the member, (= KL)
Pn : Nominal compressive strength, kips (N)
r: Radius of gyration
λ: Width-to-thickness ratio for the element as defined in Section B4.1
λr : Limiting width-to-thickness ratio as defined in Table B4.1a

Members with Slender Elements Excluding Round HSS §E7.1

This section applies to slender-element compression members.

The nominal compressive strength, Pn, is determined based on the limit states of flexural buckling, torsional buckling, and flexural-torsional buckling in interaction with local buckling.

Effective areas of the cross-section, Ae, based on reduced effective widths, be, de or he.

Critical stress, Fcr, is determined by limit states of Flexural Buckling or Torsional and Flexural-Torsional Buckling.

• When

• When

TABLE E7.1
Effective Width Imperfection Adjustment Factors, c1 and c2

Case

Slender Element

c1

c2

(a)

Stiffened elements except walls of square and rectangular HSS

0.18

1.31

(b)

Walls of square and rectangular HSS

0.20

1.38

(c)

All other elements

0.22

1.49

Round HSS §E7.2

The effective area, Ae, is determined as follows:

• When

• When

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