Moving a Lolly/Lally Column

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Devans175

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I have a Lolly column in the way of my pool table in my basement. It supports a pretty beefy steel I beam. The beam spans 24 feet and the column is dead center. 4 feet would get me plenty of clearance for my pool table. The house is a rancher. I plan to have a structural engineer/contractor review it, but I was wondering if anyone had any opinions. Is there a rule of thumb when it comes to maximum unsuported spans on I-Beams?

Also, Is it Lolly or Lally? I've seen and heard both...
 

Frenchie

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I've heard both, also.

There's no rule of thumb, it depends on the size of the beam, the loads it's expected to support, etc... all specific to your house.

The easiest thing'd be to replace the one, at midpoint, with two at the 1/3rd marks. If the beam's good over twelve feet, you already know it'll be fine over 8 feet.

Caveats:

- if there's a point load (like a loadbearing column, or one side of an arch) directly above... you're probably SOL. Get an engineer in to see what other solutions might be.

- the new columns will need solid footings. This may require breaking open your slab, digging down, and pouring a footing.

- put in the two new ones before removing the old one. (I know it's obvious, but you'd be surprised how often people don't think of it)
 

Devans175

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Thanks for the info. The 1/3 points won't work either, though. The second column would then be in the way. The beem is 8 inches high and 8 inches wide. I was just hoping to get an idea if it was even feasable before I hire an engineer to look at it. There shouldn't be a column above the one in the basement. There is a load bearing wall above it though. It caries the load of the ceiling joists for the main floor of the rancher.
 

FloridaOrange

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If you can get bearing for the new beam set as a sister beam it should work. I'd talk to the engineer, it may be easier than you think.
 

Leejosepho

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The beem is 8 inches high and 8 inches wide.

That sounds like an 8" wide-flange beam that weighs about 8.5 lbs. per foot, and if so, that means it is likely not bearing a great load. Hence, and subject to things already mentioned, I would suspect your center post could be moved four feet without any over-stressing of that beam.

There is a load bearing wall above it though. It caries the load of the ceiling joists for the main floor of the rancher.

If you actually have trusses rather than mere ceiling joists, then the weight of the roof rests primarily on those trusses that rest on your outside walls. And if so, then that "load-bearing wall" down the center actually bears little more "load" than that of holding itself rigid ... and that leaves only your floor system as the bulk of the load on that beam.

Get a couple of professional opinions on-site, and I would bet that post can be moved.
 

Phil H2

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That sounds like an 8" wide-flange beam that weighs about 8.5 lbs. per foot, and if so, that means it is likely not bearing a great load. Hence, and subject to things already mentioned, I would suspect your center post could be moved four feet without any over-stressing of that beam.



If you actually have trusses rather than mere ceiling joists, then the weight of the roof rests primarily on those trusses that rest on your outside walls. And if so, then that "load-bearing wall" down the center actually bears little more "load" than that of holding itself rigid ... and that leaves only your floor system as the bulk of the load on that beam.

Get a couple of professional opinions on-site, and I would bet that post can be moved.
leejosepho,
I don't understand how you can make any of those assumptions. The current edition of the Steel Construction Manual doesn't list a W8x8.5 the lightest W8 is 10 lbs and it is only 4 inches wide. There are several W shapes that are close to the stated dimensions, and the lightest of those is 31 pounds per foot. Assuming a uniform load on the beam and increasing the span from 12 feet to 16 feet, the maximum shear stress in the beam will increase about 33%, the maximum bending stess will increase ~78% and the maximum deflection increase over 300%. Why do you suspect moving the column won't over-stress the beam?
 

Leejosepho

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I don't understand how you can make any of those assumptions.

In general, roofs sit on trusses on outside walls, a finished wall is similar to a laminated beam and can support much, most or even all of its own weight within its length or with just a little help from below, and that leaves the floor as the primary weight the beam is intended to carry.

The current edition of the Steel Construction Manual doesn't list a W8x8.5 the lightest W8 is 10 lbs and it is only 4 inches wide. There are several W shapes that are close to the stated dimensions, and the lightest of those is 31 pounds per foot.

It has been many years since I worked full-time fabricating structural steel, but I think I recall something close to what I had described. We used it for support structure under box-car-size dust collectors. In any case, it was 8x8, but maybe I am wrong about the weight.

Assuming a uniform load on the beam and increasing the span from 12 feet to 16 feet, the maximum shear stress in the beam will increase about 33%, the maximum bending stess will increase ~78% and the maximum deflection increase over 300%. Why do you suspect moving the column won't over-stress the beam?

Because the floor system is likely relatively light and the only major load on it. However, a qualified engineer should definitely be involved in making the actual decision here ... or, one could do a little ad-hoc testing with a couple of posts and a jack to see what deflection might actually take place. Some things can look either good or bad on paper, but that is not always the final story!
 

Frenchie

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Uh, Lee...

- if the roof is trusses, and not getting support from the wall... and the wall can basically hold itself up... why is there a beam underneath it? In my experience, if there's a beam right under the wall, it's because the wall's holding something up.

- roofs are not "generally" on trusses. SOME roofs are on trusses. If he'd mentionned that it was brand-new house, in a suburban tract... maybe. But you don't even know how old the house is. Considering the wall-over-beam situation, I think he probably has a double-purlin roof (picture below).

- not sure I agree with the bit about finished walls acting as a laminated beam. Might be true of a simple partition wall, framed in light-gauge steel... but in this case, it's likely wood-framed. So it all depends on how it was framed, what it's sheathed with, the fastening schedule... Unless it's a shear wall, that's a ridiculously over-reaching assumption you're making.


In short, I think your advice is kind of reckless on this one.
 

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Leejosepho

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- if the roof is trusses, and not getting support from the wall... and the wall can basically hold itself up... why is there a beam underneath it?

To support the floor joists coming in from each side. And of course, there is certainly some weight from the wall and whatever is above it.

In my experience, if there's a beam right under the wall, it's because the wall's holding something up.

And in mine, the beam was there holding the floor while we set the outside walls and trusses and finished the roof and rocked the ceiling before any interior walls were anywhere at all.

- roofs are not "generally" on trusses. SOME roofs are on trusses.

Understood.

If he'd mentionned that it was brand-new house, in a suburban tract... maybe. But you don't even know how old the house is.

He had mentioned ceiling joists, and if that is what he actually as, then your own assumption might be more accurate:

... I think he probably has a double-purlin roof.

But even if that is the case, that does not mean he must automatically or immediately abandon the idea of moving the post in his basement.

- not sure I agree with the bit about finished walls acting as a laminated beam ...

Even a mere hollow-core door could be used on its edge as a "beam".

So it all depends on how it was framed, what it's sheathed with, the fastening schedule...

Surely.

I think your advice is kind of reckless on this one.

Here is the only advice I have given:

Get a couple of professional opinions on-site ...

What is reckless about that?!
 

Toolaholic

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As a cert. welder ,Ask the engineer about boxing the beam between the 2 LALLY Cms. 2 new footings are necessary
 
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