Force acting on a circular bended plate to form a steel pole

[gasma1975]

Hi,

I have a rounded taper steel mast 40' long. It is made of a steel plate rolled and bended to form the pole. I was wondering if there is a way to calculate the force acting on the longitudinal weld ?

Anyone has an idea ?

Thx

gasma1975

 

[dik]

If the pole is essentially in flexure, then the relative sides of the weld don't move... therefore, no shear. From the lateral loading, the shear stress will vary depending on the direction of the load to the weld. This can be calculated using the standard shear formula. tau = V*A'*ybar/(I*b) if memory serves.

Dik

 

[Denial]

I think that the OP is asking about the tension force acting directly ACROSS the weld resulting from the plate's reluctance to being bent to form a pole in the first place.[ ] If so, these forces will be highly dependant upon the method used to form the circular cross-section before doing the welding.

 

[dhengr]

Gasma1975:
Generally speaking, when the pole is properly formed and fit-up, there should be no great amount of stress across the longitudinal joint due to the forming of the original plate. When properly formed, usually either by break forming or roll forming, the plate material is yielded as it is formed into its final shape and the joint should essentially close up, and with a little fit-up force be ready for the longitudinal welds. The same joint will see stresses in actual use, due to various loading conditions. I’m sure that a sheet of steel could be wrapped around a mandrel, with the longitudinal edges just touching, and then this seam is welded. But, this is not normal fabrication for most of these types of poles.