Square tubing calculation

[MFW]

How did you find PF?: Internet search

Hello, I'm new to the forum. I am a welder and machinist. I am building a roof over my patio. For design reasons I want to use 4 inch square tubing for columns and cross beams. Will the 4x4 sag over a 20 foot span. There will be approximately 600 pounds of roofing materials it will be supporting

 

[berkeman]

Welcome to PF.

Did your city Building Department approve your plans?

 

[MFW]

Thanks for the reply, I talked to the county inspector and he said that it was legal to do what I want to do put I need to submit the drawings. I have drawn what I want, now trying to figure tubing size for structural integrity

 

[berkeman]

4 inch square tubing

What is the material and the wall thickness? Can you upload a drawing (use the "Attach files" link below the Edit window)? What wind loading do you expect on this roof? How is it tied to your house?

 

[MFW]

My thought was hhs 4x4x3/16. Will be attached to the concrete pad with 1/2 inch concrete anchors (6×6×1/4 steel plates welded to the bottom of 4x4 columns. Will have to figure out the upload, not computer savvy hahaha. Basically 4 columns cover 12 ft wide x 19 ft long by 12 tall with 3 12 roof pitch. Metal roof and bracing about 700 pounds or less. Very little wind load because of surroundings and almost never any snow load being in the south