Bent Plate versus Angle in Hanger connection

[KRW]

I am looking for any information regarding any potential impact of using a bent plate versus an angle for a specific connection condition.

One leg of the connection is vertical, the other is horizontal. Load is applied to this connection in multiple directions, but the primarly load is in the vertical direction.

I am trying to find out if there is less capacity in this connection if it is built with a bent plate versus an angle (3/8" thickness in either case). My concerns include the effect of the fabrication bending of the plate and the potential effects on the weld at the "heel" of the bent plate (to the member it supports).

This is an as built condition that was supposed to be constructed with an angle, but was built with a bent plate.

 

[flamby]

If the same sectional properties are availabe in a bent plate as that in an angle, there will not be any reduction in the capacity if I am percieving your structure rightly. However, the answer lies in the detailing of the joint b/w horizontal and vertical members. The joint should be equally stiff in bent plate case as in angle scenario. If you are planning to curve this bent plate itself by 90 degrees to make horizontal and vertical part, the results can be drastic due to local buckling.

 

[JAE]

I've had many fabricators tell me they don't bend plates thicker than 1/4" normally because they get cracking at the bend - I think they are probably not bending it to a limited radius for the thickness - I would check out the actual in-place radius at the heel and compare that with an old AISC table found in the 9th Edition (ASD) on page 4-174, titled "Bent Plates". It doesn't specifically say this, but the intent seems to be that if you limit your bend radius to what is shown in the table, you can treat the steel as though it was rolled that way.

If the actual bend radius is significantly tighter than the table limits, I'd be concerned that there has been some damage done to the elbow and I would add stiffners along the bent plate length to hold up the horizontal leg.

 

[jcrowe]

If the load is applied in a vertical down orientation and the correct bend radius is in the bent plate, then the load is not carried directly vertical down as it would be if angle had been used. The bend radius in the plate causes the load to be applied to the bend as an offset not true vertical and so the load will affect the bent plate differently than it would if angle had been used. The bent plate will NOT carry as much vertical down load as an angle of the same thickness would, also any cracking in the material at the bend raduis from too small a radius will adversely affect the strength of the bend, this will also greatly increase the loss of material/strength due to corrosion in the cracks at the radius.