Building an all metal car port. I need help with specifics.

So I'm going to build an all metal free standing car port. The car port will be 20'x20'. The posts will be 3"x3". But I can't find out how deep the posts should be secured in the ground using quickcrete. Also, would four posts, one at each corner, do? If I need more than four posts, how far should they be separated? I would like to make it as structurally sound as possible. Any advice is welcome.

Submitted April 30, 2016 at 05:40AM by EpicHorizons http://ift.tt/1VXXSbg