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E: Modulus of elasticity of steel = 29,000 ksi (200 000 MPa)
Fy: Specified minimum yield stress of the type of steel being used, ksi
h: Distance as defined in AISC 360-16 Table 4.1b
Lb: Length between points that are either braced against lateral displacement of the compression flange or braced against twist of the cross-section, in. (mm)
Lp: The limiting laterally unbraced length for the limit state of yielding, in. (mm)
Lr: The limiting unbraced length for the limit state of inelastic lateral-torsional buckling, in. (mm),
Mn: The nominal flexural strength
Mp: Plastic bending moment
My: Yield moment about the axis of bending, kip-in. (N-mm)
Sx: elastic section modulus, in.3 (mm3)
Sxc: elastic section modulus referred to the compression flange, in.3 (mm3)
Sy: elastic section modulus taken about the y-axis, in.3 (mm3)
tf: the thickness of the flange, in. (mm)
Zy = Plastic section modulus about the y-axis, in.3 (mm3)
λp: Limiting slenderness for a compact flange, defined in Table B4.1b
λr: Limiting slenderness for a noncompact flange, described in Table B4.1b
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The plastic bending moment, Mp, for tee stems and web legs in tension is calculated as shown below.
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The yield moment about the bending axis, My, is calculated as shown below.
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The plastic bending moment, Mp, for tee, stems in compression is calculated as shown below.
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The plastic bending moment, Mp, for double angles with web legs in compression is calculated as shown below.
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Limiting laterally unbraced length for the limit state of yielding, Lp is calculated as shown below.
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Limiting unbraced length for the limit state of inelastic lateral-torsional buckling, Lr, is calculated as shown below.
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The limit state of flange local buckling does not apply for tee flange sections with compact flanges in flexural compression.
The nominal flexural strength, Mn, is calculated as shown below for tee flange sections with noncompact flanges in flexural compression.
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The nominal flexural strength, Mn, is calculated as shown below for tee flange sections with slender flanges in flexural compression.
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Local Buckling Limit State of Tee Stems and Double-Angle Web Legs in Flexural Compression
The nominal flexural strength, Mn, for tee stems is calculated as shown below.
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The critical stress, Fcr, for tee stems is calculated as shown below.
Mathinline body --uriencoded--$$ \normalsize F_%7Bcr%7D = F_y \; \;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\; \mathrm%7Bwhen%7D \;\; \dfrac%7Bd%7D%7Bt_w%7D \le0.84 \sqrt%7B\dfrac%7BE%7D%7BF_y%7D%7D $$ Mathinline body --uriencoded--$$ \normalsize F_%7Bcr%7D = \Bigg( 1.43-0.515\dfrac%7Bd%7D%7Bt_w%7D\sqrt%7B\dfrac%7BF_y%7D%7BE%7D%7D \Bigg)F_y \; \;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\; \mathrm%7Bwhen%7D \;\; 0.84 \sqrt%7B\dfrac%7BE%7D%7BF_y%7D%7D < \dfrac%7Bd%7D%7Bt_w%7D \le 1.52\sqrt%7B\dfrac%7BE%7D%7BF_y%7D%7D $$ Mathinline body --uriencoded--$$ \normalsize F_%7Bcr%7D = \dfrac %7B1.52E%7D%7B (d/t_w)%5e2 %7D \; \;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\; \mathrm%7Bwhen%7D \;\; \dfrac%7Bd%7D%7Bt_w%7D > 1.52\sqrt%7B\dfrac%7BE%7D%7BF_y%7D%7D $$
The nominal flexural strength, Mn, is calculated for double-angle web legs given the title.
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