UnSafe Beam Bearing?

[mfreed]

I just purchased a new home approx 3K SF. It has 6 steal i-beams in the basement most with at least 1 support column.

My question is about the end bearing of one of the beams. 5 of the beams have 4-5 inches of bearing while 1 beam has only 2.5 inches on the foundation. I don't believe the beam was ordered incorrectly, but rather installed 1-2 inches off its intended position. The other end of the beam has about 1-2 inches of overhang over the support column with nothing being supported.

The beam is 8 inches high and about 13 feet long. The foundation is 8 inches of poured 3000 PSI concrete. There is also a piece of thin steel under the beam on the bearing of the foundation. I assume it is a shim?

Finally the question.. Is this an unsafe condition? If so what action can be taken to correct? Could be beam be slid over 1-2 inches, or perhaps an additional column as an insurance policy?

Thanks in advance for the advice.


I just updated. I was using the word column when I meant to say beam.
Thanks.

[Rich]

i've always tried for at least 3" of bearing for any beam, or joist. Will .5" effect your beam? I have no idea - you'll probably have to get an engineer to come out and look at it.

[mjpliv]

I agree with Rich about the engineer.

If I was a betting man I would say no problem! As Rich stated, 3" is a common default bearing requirement for beams. But we, as a group, use these defaults that were developed for general applications where the structural members are assumed to be "maxed" out. Therefore there is always a fair safety factor built in.

Assuming the beam flange is 6" wide then your concrete should be able to handle a 45,000 pound load bearing on the 2.5" surface.

[mfreed]

Thanks for the great information. I have the GC coming out tomorrow morning. He said if the pocket is level it should be OK, otherwise he would put a 4x4 under it (the footer extends 6-7 inches beyond the wall). I don't feel too good about that. I'll settle for another lally, but at that point its really over kill since the beam is only 10ft wide (I was wrong on previous post). One end is the foundation the other is a 3.5" lally rated for 14K lbs.

I'm going to request that the engineer who designed the home signoff, if not I need to have some correction taken. The house has been standing for 10 months but you never know.

It really makes me mad that 5/6 beams were installed perfectly and this beam was plenty long, the guy who installed it left 2 inches overlap on the opposing lally.

Just out of curousity what does a 3Ksf home weight - ball park? 45000 lbs, I would think the entire house doesn't weight that much!

BTY: I'm new to this forum - it's a great site, very imformative for your average homeowner like me. Thanks!

One more question - Would be be possible to jack the floor joists just enough to remove the weight from the beam and shift it 1.5 inches? It's a long shot I guess.

[mjpliv]

Most floors will be designed for 40 lb (squ ft) live load and 15 lb (squ ft) dead load. If you have a concrete over-pour on the floor you can add between 20 and 25 pounds dead load.

We separate the live and dead load because the safety factors for each are calculated differently. Live loads are factored at 1.5 times the actual load while dead loads are factored at 1.25 times the actual load.

[mfreed]

Were you responding to the correct post? OR trying to help me calculate how much an given portion of house will weigh?

[Rich]

You would probably have to pull all the nails from the joists into the beam (the joists are sitting on top of the beam?)... but could probably be moved in that way. Could be a pretty major undertaking also - just don't know enough about the rest of the house to make an educated guess. :)

[mfreed]

I understand. Yes the joists rest on the beam. There is 7-8 joists that are resting on it. It was just an idea since the beam is long enough. I figure the beams weighs about 800lbs (80/ft).

The reason I am so sensitive to this we just sold a townhouse and the buyers inspector noticed that the only beam in that house had less than 2" of bearing on each end. He was concerned that should a "earthquake" type of event occur (Not likely in SouthEastern PA) the beam could shift. He said it wasn't a big deal since the rest of the house could calpse anyway, but he said for extra insurance he would install a lally column.

Even if the builder deems my current house within tolerances I may just have one installed as a precaution. It seems to be a small investment. My builder is well respected and takes his reputation very seriously, I hope he does the right thing.

There is a metal shim under the beam in question about 5mm thick. It is 6x5 inches with the beam sitting squarly in the center. I wonder if that helps dispurse the weight of the beam a little more evenly.

OK - No more questions until I have the GC and Architect take a look.

[Rich]

I would imagine the shim is just to bring it up to elevation.

[mjpliv]

I posted the per square foot weights so you could calculate the load on the end of the beam.

[mfreed]

Here's an update.

I met /w the builder this morning and he felt that because the pocket was level with all the corner material intact(sometimes they are not) and since there was 2.5" of bearning and this beam supports only of 580sf of living space .(290 on each floor) + the weight of a 13ft first floor wall. The roof is not supported in this location. He said anthing less than 2 inches his framers usually bring to his attention and he will correct immediately.

I told him I was still uncomfortable and he said he will install another column right next to the foundation wall to give me piece of mind since the beam was not installed to full spec. At first he said a 6x6 strainded wood member but I suggested another 3.5" lally for appearence purposes. He agreed since the cost would be less for a steel lally.

He said the footer extends 7" past the wall so there shouldn't be a need to crack open the floor to increase the footing. After all, the only way this beam will ever bear any weight i if there is total foundation failure. This beam will be stronger than any other in the house at this point.

The beam width is 5.25" and 2.5" of bearing should mean that the beam on that end will support 39K lbs. The lally on the other end of the beam is rated at 18K so I assume the the builder is correct about being sufficient w/o adding a column.

580sf * 40lbs live load = about 24K of total load. But that load is distrubted to one lally, this foundation pocket, and on the opposite wall of the foundation.

I was pleased he was willing to cooperate. He also told me of a recent horror story about a home he inspected for a friend in which the beam had 1" of bearing on each end of the beam.

[mfreed]

Ok - What do you think of this....

The problem /w puting in another lally directly against the foundation wall is that there is a 4" main sewer pipe running along that wall.

The builder is recommending having the steel company create a 1x3" steel i-beam /w backets welded on each end and the entire thing will be placed on end and bolted to the wall, floor and attached to the beam. I was reading another post that talked about i-joists being placed vertically was not good. Does the same apply to steel? I'm trying to remember if I've ever seen steel put on end.

The reason to go /w the 1x3" is so the post can be placed between the pipe and the wall adding 1 inch of bearing to the beam.

I'm getting to point where maybe another footing should be placed 12" from the wall and a lally put in.

This whole thing could be a big waste of time and I'm just being paranoid. I should probably consult an engineer and be done /w it.

[mjpliv]

Try this.

Order a steel shim to fill in the base of the beam pocket not used by the steel beam and high enough to match the height of that beam.

Order two lengths of 4-1/2" steel angle about 12"-18" long. Clamp the angle iron to the web of the steel beam so they project into the pocket and over the shim(s). Weld those suckers in place (continuous welds - both legs of the angle) and spot weld the ends to the shims.


You now have a safety net in the event of beam movement caused by seismic activity. Have a look the this sketch.

Clear as mud?

[mjpliv]

I thought it would be easier to extend the beam rather than the bearing.

[mfreed]

The builder had roughly the same idea; however, he is reluctanct to have a torch in the house.

All of this for .5"
My $1/2 million house is starting to sounds like a hack! :)