I am putting up a second story in a small building I want to create a framework to carry the load of the addition. I'm putting in piers and posts, which I have found correct info for. I have a stock of lumber, 4x6's and 6x8's, I would like to use the 6x8's. They would be supported by the piers and posts, one exact set on each under side of structure. The total load they would carry is 4500 lbs. so two sets of, two piers and posts with 6x8 beam spanning 8'. Hope this is not too confusing! Lol Thanks for the help
I'm not sure I understand where the posts and piers are in relation to the 6x8's. However, I can give you some info and maybe you can interpret.
According to Western Woods Use Book by West Coast Lumbermen’s Association, 1973 edition, a 6x8 beam can support about 8,000 lbs., depending on species of wood, grade, etc. on an 8' span.
Just went through something similar. You can check local building codes at city hall for that and more if necessary.