Free standing patio cover advice

[250]

We have this mechanical area behind out house that we'd like to build a patio type structure to cover. The rough dimentions are 20ft long, 8ft wide, and about 9ft high. Something like this.



And the area to cover. Ignore the mess.


We'd like to build it out of metal instead of steel instead of wood. I could use some advice/pointer as how to translate from wood over to steel for appropriate sizing and such.

Thanks for the help.

 

[cvairwerks]

Take your design cues from free standing pergolas. You will need to design your corners to prevent racking of the structure.

 

[king nero]

Counter-intuitively, but a necessity if you have any significant wind over there: make sure you provides measures against uplift. The vertical upwards force usually exceeds by far the gravity forces from own weight and snow loads and such.

And yes, use moment resisting (fully welded) corners or forsee bracing (diagonals) in the upper corners, and base plates bolted in concrete footers. The picture in your post doesn't look like it would resist any significant sidewards forces (wind, seismic, ...).

Sizing the members isn't that hard, there are no loads that a common found HSS couldn't react. I'm thinking 2.5 x 2.5 x 1/8" thick square hollow tube for the columns, and a rectangular tube that's a bit higher for the 20 ft horizontal span. Depending on the roof covering and how yo want to fasten it, smaller T's or 2 by 6 for the cross beams.

 

[250]

Here was the basic design I was thinking. Bolted down, fully welded joints. I was also thinking more in the 4x4 range for the posts, mostly because that looks right in my head. For the horizontal members, is a rectangular member preferred over a square member?