D12.A.6.1 Double symmetric wide flange profile
The von Mises stress is checked at four stress points as shown in figure below.
Stress points checked for a wide flange section
Section Properties
- A_{x} , I_{x} , I_{y}, and I_{z} are taken from STAAD.Pro database
- A_{y} = h × s Applied in STAAD.Pro print option PRINT MEMBER STRESSES
A_{z} = (2/3)· b · t · 2
τ_{y} = F_{y}/A_{y}
τ_{z} = F_{z}/A_{z}
- A_{y} and A_{z} are not used in the code check
- ${C}_{w}=\frac{{(h-t)}^{2}{b}^{3}t}{24}$ref. NS app. C3
T_{y} = dA × z
T_{z} = dA × y
Stress calculation
General stresses are calculated as:
$\sigma ={\sigma}_{x}+{\sigma}_{by}+{\sigma}_{bz}=\frac{{F}_{x}}{{A}_{x}}+\frac{{M}_{y}}{{I}_{y}}z+\frac{{M}_{z}}{{I}_{z}}y$ |
$\tau ={\tau}_{x}+{\tau}_{y}+{\tau}_{z}=\frac{{M}_{x}}{{I}_{x}}c+\frac{{V}_{y}{T}_{z}}{{I}_{z}t}+\frac{{V}_{z}{T}_{y}}{{I}_{y}t}$ |
Where the component stresses are calculated as shown in the following table:
Point No | σ_{x} | σ_{by} | σ_{bz} | τ_{x} | τ_{y} | τ_{z} |
---|---|---|---|---|---|---|
1 | $\frac{{F}_{x}}{{A}_{x}}$ | $\frac{{M}_{y}}{{I}_{y}}\frac{b}{2}$ | $\frac{{M}_{z}}{{I}_{z}}\frac{b}{2}$ | $\frac{{M}_{x}}{{I}_{x}}t$ | 0 | 0 |
2 | " | 0 | " | " | $\frac{{F}_{y}}{{I}_{z}}\frac{bt{h}_{2}}{2t}$ | $\frac{{F}_{z}}{{I}_{y}}\frac{t{b}^{2}}{8t}$ |
3 | " | 0 | $\frac{{M}_{z}}{{I}_{z}}{h}_{1}$ | $\frac{{M}_{x}}{{I}_{x}}s$ | $\frac{{F}_{y}}{{I}_{z}}\frac{bt{h}_{2}}{s}$ | 0 |
4 | " | 0 | 0 | " | $\frac{{F}_{y}}{{I}_{z}}\frac{(bt{h}_{2}+0.5{h}_{1}^{2}s)}{s}$ | 0 |
In general wide flange profiles are not suitable for large torsional moments. The reported torsional stresses are indicative only. For members with major torsional stresses a separate evaluation has to be carried out. Actual torsional stress distribution is largely dependent on surface curvature at stress point and warping resistance.