Corner Joints with fillet welds.

[RARWOOD]

Is the strength of a corner joint made with fillet welds the same as a corner made by bending a plate?

I design a lot of glulam hangers that use U shaped bearing seats. The type of hanger I design are similair to Simpson LEG hangers or some of their other heavy duty glulam hangers.

Simple hangers are often made by taking two standard 3x3x 1/4" angles and welding a flat bearing seat between the vertical angles.

The common method of joing the parts is to place the plate so that its upper corners are touching the inside corner of the angles. The only place the angles and plates touch are at their corners.

Then a 1/4" fillet is placed on the outside of the joint with a 1/8" fillet on the inside of the joint.

 

[Goahead]

The best way to compare different designs against requirements would be to test by applying loads exactly as they will be sustained in service and by continuing to failure.

http://www.welding-advisers.com/

 

[Kwan]

For pure tension compare the area.
For bending compare C/I.
For compression look at area and I. But be careful here because crippling strength is different depending on how much material is in the corner.

 

[Kwan]

Oh! I forgot the most important consideration. Due to the welding you have degraded the material as compared to forming. And depending on how tight the bend radius is there may be problems with cracking. Anyway, don't forget to account for the reduced strength due to the weld.

 

[RARWOOD]

Thank you, all, for the poosted information.

Goahead is right, the best way to answer the question is with testing of the welded hangers. The question arises in the first place because hangers from companies like Simpson use much thinner steal then what would appear to be required by calculations.

So when you design a hanger by hand, people expect you to use the same size plates as Simpson. However the design loads of the Simpson hangers, have been verified by load tests. Also Simpson bearing seats use bent plate while hand design hangers use welded bearing seats.