Originally Posted by MoreCowbell
My concern now is how/if to fill the pipes with concrete. But that is a new issue so I started another thread.
Something to think about before starting another thread on filling with concrete--a Schedule 40, 4" pipe (actual outside diameter of 4.5", wall thickness of 0.237") is capable of carrying a total compressive force of slightly less than 67,000 pounds. Based on a total steel area of 3.17 sq. in., and allowable compressive stress of 21,050 psi, Kl/r = 1.48. In other words, if your living room furniture weighs more than 33.5 tons per column, or you're possibly expecting lots of very heavy house guests, then yes, by all means fill the little buggers with concrete. Good luck on getting it in there.
On the other hand, should you choose to come back from the dark side of anal-hood, and just leave the pipes empty, that would be perfectly acceptable also. And one heck of a lot easier.