How does ideCAD calculate steel compression strength with slender elements according to AISC 360-16?
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The compression strength of steel elements is calculated automatically according to AISC 360-16.
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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.
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TABLE E7.1
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|---|---|---|---|
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Case |
Slender Element |
c1 |
c2 |
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(a) |
Stiffened elements except walls of square and rectangular HSS |
0.18 |
1.31 |
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(b) |
Walls of square and rectangular HSS |
0.20 |
1.38 |
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(c) |
All other elements |
0.22 |
1.49 |
Round HSS §E7.2
The effective area, Ae, is determined as follows:
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When
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When