what is the reference of this steel design formula?

[far_]

that is teh formula to calculate hollow steel of horizontal waling in formwork structure. And what i want to know is, where i can find the references of the formula of permissible bending stress, maximum design bending stress , permissible shear stres and design shear stress used on that pic i send.
is that from BSi or another standart.

 

[msquared48]

Could you please be a just a little more definitive in your request?

Mike McCann, PE, SE (WA)

 

[far_]

that is teh formula to calculate hollow steel of horizontal waling in formwork structure. And what i want to know is, where i can find the references of the formula of permissible bending stress, maximum design bending stress , permissible shear stres and design shear stress used on that pic i send.
is that from BSi or another standart.




the determination of hollow steel properties

 

[JedClampett]

It looks like the allowable bending stresses are .6 times the yield stress, used in the AISC 9th Edition. Shear allowable is .37 times yield, which is very close to the .4 times yield used in the 9th Edition of AISC. I'm not sure these are in any code (although they align with old AISC allowables), but more like rules of thumb for bracing designs.

 

[Settingsun]

Hi Far_,
Do you have the whole book that the example is from? It should say in the text which standard the design check is based on.

The formulas for bending and shear permissible stresses are common. The 0.6 bending factor and 0.37 shear factor are the same as in the Australian Standard AS 3990, and similar in AISC as JedClampett said above (AISC rounded the 0.37 to 0.4). These provide about a 1.5 safety factor on the ultimate strength.

The formula for maximum design bending stress is M/Z, but they've rounded off both M & Z and converted them to units of Newtons (N) and millimetres (mm).

The formula for design shear stress is V/A, but again they've rounded off the numbers and converted the units which makes it a bit hard to follow. I'm not convinced that using the full section area is correct as it's usually just the web area. It would be good if we can work out which standard is being followed to check that use of the full section area is allowed by it.