supporting 200lbs on center of a 14' span.

[TinnerDave]

I am trying to support 200lb duct on a 14' span. I would prefer to use angle, but am not opposed to channel if it's necessary. My gut tells me 4x4x1/4 is safe, maybe 3x3x1/4. i would like to use beam clamps on the edge of the horizontal leg, but can drill closer to the vertical leg if i gain some capacity by reducing torsion. any help is much appreciated. thank you in advance.

 

[WARose]

I have some tables that cover laterally unsupported angles......and for 14', they both show that L4x4x1/4 & L3x3x1/4 as being ok for flexural loads (i.e. the load you called out; A36 steel used). By the way, that doesn't include a deflection check.

However these tables don't check torsion (shear) stresses or rotation. So that would be an additional check that would need to be done.

 

[spieng89]

I'd just check the flexural capacity of the section at max moment (PL/4) and deflection. You could always use a double angle (two smaller angles 1 1/2" X 1 1 1/2" leg to leg) if you are worried about torsion