Edge Stresses in tubes

[deejay]

Hello everyone:

I am trying to design a cantilever sign structure. I have to use a square tube for the column (post) due to some constraints. As you are aware, edge stresses build up at the base of the tubular members. According to membrane theory, the bottom has to be reinforced (stiffened) to resist these edge stresses. Can anyone tell me how high the stiffener has to go? i.e. limits of edge stress build up?

 

[ishvaaag]

If the tube is an ordinary commercial square tube you may apply the applicable code and standard designs for the base connection, for so is the general practice and provided the applicable codes are truly followed no special problems develop.

To say that no special problems develop means that only ordinary problems, seen sparsely here and there, but not frequently, may still appear. For example, aging will cause the structure be with time defficient on one or other basis, but these concerns are outrightly dismissed in the reduction process of designing something according to a code.

Respect the details of a base connection, there are so many that one must judge case by case, and in consideration of the corresponding design and analyses. However, stiffeners 3 times tall the side width welded should ensure complete transfer of any forces at the base if the elements are suitably designed. This stiffener height may be nil, no stiffener, for some cases. It is the design and corresponding analysis what rules.

 

[deejay]

Thank you Ishvaaag for the input.