I figured that since Sox wasn't around, I'd give it a shot, and only because I saw Ed's posts and wondered what his posts contained.
I'm familiar with steel construction but not aware of any structural member that would be 4" thick. Deep or wide or cross section, sure...but not thick.
You know what I did one day? I spent a few hours actually reading the comments that structural engineers and architects on the A&E site had to say. If you click on their profiles, many of them have comments...in fact, most of them do. Click on "975" or whatever the top number is, and then scroll down a little on the new page, and there's the list of the architects and engineers. If you're not curious, then of course, don't bother. http://www.ae911truth.org/