web reference for steel I-beam span

[hubops]

Hi All ;

I'm planning to have my < ~ 28 year old > basement completely remodeled - just starting to make floor-plans. One obvious issue is the location of the single jack-post supporting a 24 foot long ,

8 inch steel I-beam - it's central to the I-beam - great ! but .. also directly in front of the stairs and just 6 feet from the stair bottom - very poor original design, I know ! It makes it impossible to hide it inside a wall without badly chopping the basement up. And the location is visually very poor for just boxing-it-in. My contractor thought that by increasing to 12 inch I-beam and moving the single jack-post location would take care of things nicely. < 8 ft ceiling would be reduced > I don't disagree but wondered afterward if we could keep the existing I-beam and install 2 new jack-post locations if we maintain a 12 foot max. span ? If anyone has a good web reference - please post the link - thx. I'm not expecting to get structural engineering answers here - nor from a web site link - but I wish to propose an informed proposal - or save the waste-of-time in my idea. ps: the basement I-beam supports only the floor above and its roof - not a second floor. John T.

[dpb]

For uniform loading w/ simple support, the deflection will be the same for the same span so it all depends on what's actually being supported and where but two posts at spacings 6-12-6 from wall-to-wall is obviously much stiffer at the two outside areas and the same in the center as what exists both sides.

The question again is whether there's any point load like the 40 cu-ft freezer/refrigerator, etc., etc., etc., ... where the support is being moved from.

Of course, what details one finds on opening up the existing ceiling to find it's actually two 12-footers resting on the column or the like is something else again... :)

There are any number of online beam deflection/stress calculators online.

[Ed Pawlowski]

This may help.

A friend built a 2 story with a 28' span and 12" beam. Inspector said is was ok but would like to see a support anyway. He put one in the center but could have spaced out two. You may want to discuss this with your local inspector too.

Can't ask for more information or calculations as my friends died a few years ago.

[gfretwell]

When I put an addition on my house in Maryland the normal deal was an

8" 17 pound beam supported at 12-13 feet. I really did not want a post in the middle of my garage and I just asked the inspector what he would accept if it was there. He said if I had an 8" 34# it would be OK. The second floor never fell in but it was a tad "springy". Now I know. pay an engineer or just go nuts with a huge beam. Deeper is better than heavier. It turns out after asking around if I had used a 10" 34# I would have been OK. OTOH is you can live with 2 posts instead of 1 and you maintain the same 12' as your widest span, you should be OK assuming there are no load bearing walls in that span. These days load bearing walls are not that common unless you have 2 floors up there.