Joist reinforcement question. Engineer types?

[fitz19d]

Not at home so will have to add pics later. Moving along in my reef project, reinforcing floors. I'm running a 6x3 tank perpendicular across as many joists as possible near where they rest on the foundation. (Basically the corner of the house.) Joists are Trusjoist TJI Pro 150's. 19 inches between them, they are 11 7/8ths tall. The top/bottom board thing is 1.5inch square.

Not as concerned about running the numbers for weight as I'm jumping straight to adding steel columns with 2 2x8 or 2x10 running across. (I guess you dont just buy 4x8 beams as that's massive) (Though I'm unsure if I should run them length of room or just to first joist past each end of the tank so the columns are closer together and right under the weight. If Running the whole length of room rather than just under tank I'd be concerned about doing it in one beam vs having to connect them end to end? Not to mention getting large things in basement already a pain with one of those POS stairs that switches back with a tiny landing)


So question basically is, since we dont have earthquakes or anything. Think I should still look into ribs or anything else to reinforce any lateral shifting/failing between the joists? Most of any sheer/bowing is covered with the extra column and beam. They just look/seem so flimsy I'm surprised they don't just fold over in half with any big weight or disturbance.

Also, Was unsure with the 2x8's, to attach them toghether, is that like a joist hangar/strap them toghether. Just nail them. Bolts with washer and nut etc?

[Wulf202]

You should find the appropriate Simpson strong tie hangers to attach them to the joist.

You can special order a 4x8 anywhere that will sell 2x8. 2 2x8 does not equal one 4x8.

I would suggest glue lam instead of 2x8. Much stronger

Yes there is a nail pattern for sistering. 3 16d every 16"

Bring the lumber in thru a window.

[jslo]

I would put the beam just under the tank, not across the whole room. If your columns are wood I'd run a king stud up the column along side the beam. If the columns are steel I'd run roll blocking at a 45° angle from face of beam up into joist bay, attaching to both top and bottom chords of TJIs.

[fitz19d]

You should find the appropriate Simpson strong tie hangers to attach them to the joist.

You can special order a 4x8 anywhere that will sell 2x8. 2 2x8 does not equal one 4x8.

I would suggest glue lam instead of 2x8. Much stronger

Yes there is a nail pattern for sistering. 3 16d every 16"

Bring the lumber in thru a window.

Thanks for the detailed info, will set to researching some of it. Glue lam? Like glue the 2x8 you mean, or laminated material instead of the wood?

Even window may not work for basement. Tight angle depending on length, I may be able to get it down stairs vertical with help but yeah.... part of why I'm leaning towards doing the beam a bit longer than tank but not whole length of room.


@JSLO Man learning so many new words. So Chords the top and bottom slat/beam on the joist eh? Seems a little counter intuitive to attach the beam/columns up to the joists because if somehow like I tripped into one of them and dislodged it somehow, figured that's a ton of stress to the joists. Then again if I knock down the column somehow, that's also a ton of weight the joists are suddenly supporting solo..... But that's just my uneducated eyeballing it thoughts.
Just so I understand it, doing the roll blocking, is that to protect the beam and columns from movement, or is it helping to support the joists from failing and rolling?

[jslo]

That's to prevent beam from rolling. To prevent joist from rolling, put blocking between joist on top of beam. A TJI consist of a top and bottom chord (the 2X2s) and osb webbing. My engineer will typically have me fill the webbing with plywood and then blocking between joist over beam.

[fitz19d]

Coming along with this, one question that came up. On the screw type joist jacks/columns. Should I perhaps pour a 1 foot square high pressure concrete footer to spread that pressure of the column, or just bolt the thing into the existing foundation and call it good. (Think most had bolt holes on bottom.)

[jslo]

Assuming by "foundation" you're talking about just the concrete floor? If you feel the weight is significant, I would not do a 1x1 raised "footer", that small a size sounds unstable and a little dangerous. If you want to spread the load go with a chunk of thick steel. I believe with what you're describing, I'd be more concerned with heaving, not load weight. If you need the peace of mind the proper way would be to cut out, maybe a 14"x14", section of concrete. Dig out and pour a caisson. There are a lot of factors and I'm not an engineer but I do work with one quite a bit.

[Wulf202]

Make sure you don't have a free floating slab

[fitz19d]

Ya, just concrete floor in basement. Someone elsewhere had expressed concern about the columns and weight on the floor. On reef forum they said 6x3 tank at filled weight was like 147lb/ft (unsure if accurate weight is 3200 to 3600 ballpark) to the floor. That getting translated over joists primarily with excess sagging weight getting taken up by beam/columns I imagine wouldn't amount to so much pressure coming down thru column to "pierce" the floor or anything?

I'm suprised a concrete block would be so unstable? Figured it would form to the floor helping ensure a level surface for column and would be fairly stuck to ground (dislodge with a hammer later if removing.) So your suggestion would be just let the column go directly onto the floor. (And again I'm assuming drill the bolts into the concrete vs just having it friction/weight fit into place? I can put a 3rd beam in over the 6 foot span if that would improve things drastically. But from what I understand I'm a little less worried about the weight as long as beam is put in right. (I'd love adding the joist or two, but that's a ton of water and electrical to cut and re-run.)

How can I tell if floating slab(See if connected to concrete walls in corners?) Significance?

[jslo]

There are basically 3 types of basement floors being used in construction these days, especially here. Your typical floating slab which is in most homes. It is a 4" slab, put in after foundation, directly on grade and not attached to foundation. Meant to be able to move independently of your foundation (which shouldn't move). The second is a structural wood floor which is attached to the foundation and above finished grade (think of a crawl space below). 3rd is a structural concrete floor. It is framed hanging from the foundation walls also but uses concrete panels for the floor.

The structural floors will require much more work for you.

You can normally tell if its a floating slab by looking around the perimeter. A 1/2" fiber expansion joint is normally used to keep it independent of the foundation. If you have a radon system that joint has probably been caulked.

What I would do (and I'm not an engineer):
Inspect the floor for signs of movement (large/uneven cracks, dropped or heaved areas)
If no signs of large movements I'd bolt the steel column directly to slab (steel shims under to plumb) and monitor from time to time for movement
If signs of anything other than minor cracks in concrete, cut concrete and add caison under post

If you could dislodge it later with a hammer, I'd consider that unstable for holding up something structural.