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Repairs for connecting steel beam to floor joists

Repairs for connecting steel beam to floor joists

Repairs for connecting steel beam to floor joists

(OP)
We are removing a couple of load bearing walls as part of renos in our home. The engineer specified a W8x21steel beam to replace the load bearing wall. The floor joists are 2x10.

It appears the contractor put the bolts into the "header" in the wrong place (not enough space between bolt and joist). He then cut some of the joist hangers to make them fit. This has been done in at least 4 out of the 10 hangers that he has installed.

Also, he used 2 1/2" layers of plywood plus a 2x8 as a header in the flange of the steel beam (see picture below)

Questions:

Has the integrity of the hanger been compromised by him cutting out part of the material?

The hangers he used are Simpson Strong Tie LUS210Z. Are these the correct hangers to use in this application since the beam is shorter than the joist by 2" and the lowest nail barely goes into the wooden

The contractor has used N10dhdg Simpson nails (.148" x 1 1/2"). Are these the right nails to use? The Simpson website specifies that common 10d nails (.148" x 3") are used with this hanger.

Is the use of plywood + 2x8 as the header acceptable or should this be replaced with a single 3x10 cut to size?
Should 2 1/2" nails be used for this header?

Per the simpson website https://www.strongtie.com/facemounthangersssl_soli...

"With 3x carrying members, use 0.162" x 2 1/2" nails into the header and 0.162" x 3 1/2" nails into the joist with no load reduction. With 2x carrying members, use 0.148" x 1 1/2" nails into the header and 0.148" x 3" nails into the joist, reduce the load to 0.64 of the table value."

Any suggestions on how this can be corrected/repaired?
Thanks

Pictures:
https://files.engineering.com/getfile.aspx?folder=...
https://files.engineering.com/getfile.aspx?folder=...
https://files.engineering.com/getfile.aspx?folder=...

RE: Repairs for connecting steel beam to floor joists

I'm no expert in residential construction, but I would say the capacity of the joist hanger is severely compromised. Had the contractor drilled the joist hanger for the bolt and put the nut and washer on so that it clamped the joist hanger to the header, it would have been stronger. As it is, the hanger shown in the second picture has essentially nothing into the header below where half or more of the hanger is gone, so all the load from the joist hangs on the thin strip of the hanger that's left beside the bolt. That means the hanger capacity is half or less of its design capacity.

I would get your engineer to look at it. If he says it's not adequate as is (which I would guess to be the case), it's possible that if the joist hangers are replaced by hangers that are drilled for the bolts and installed with the washer and nut on top of hanger, that may give it enough strength to be adequate.

Your engineer is the one who has calculated the loading of the joists, so is definitely the person to make that call.

On a side note, if it was mine, I would've notched the ends of joists to fit between the flanges and had them bear directly on the bottom flange of the beam, with blocking between the joists.

RE: Repairs for connecting steel beam to floor joists

I would remove the hanger, sister the 2x10 with another 2x10 - say 3 ft. long and then re-attach with a double hanger.
Notch the sister out for the bolt.

RE: Repairs for connecting steel beam to floor joists

This is a common issue. You have to look for a hanger that fits the condition. The nail is too close to the bottom of the framing. You should also move the bolts so that you don't have an issue. I try to frame with a ledger on the outside of the steel beam so you don't run into these issues. It can be difficult (sometimes impossible) to find a hanger where you meet the minimum required edge distances for the nails. The problem is that you need more bolts/nails/screws to connect a ledger to the wood pack and so it costs more but it is more idiot proof.

I would only knowingly accept a condition like this is the hanger was lightly loaded.

RE: Repairs for connecting steel beam to floor joists

It also appears from the photo that the nails into the joist are not driven perpendicularly into the joist, almost look like they have been driven at 45 degrees, but could just be the angle playing tricks on me though.

if you could put the required number of nails below the cut I'd tend to accept it depending on loads. Drill a few new holes maybe to attempt added more nails below the cut out bit?

Usually these things in this part of the world come prepopulated with holes which you are free to use any arrangement with provided you have the required minimum number of nails or screws, but this hanger doesn't seem to have this.

RE: Repairs for connecting steel beam to floor joists

Quote (Agent666)

It also appears from the photo that the nails into the joist are not driven perpendicularly into the joist, almost look like they have been driven at 45 degrees, but could just be the angle playing tricks on me though.

The nails driven in on a 45 degree angle are likely installed correctly, see the attached for reference.

RE: Repairs for connecting steel beam to floor joists

I see, I guess must depend on joist hanger manufacturer I guess. All locally available ones in this market are much shorter nails driven perpendicular. Least my eyes are onto it... even if I wasn't dazed.

RE: Repairs for connecting steel beam to floor joists

Yes, LUS28 has nails at 45 degrees.

In these cases, you have to spend a bit of time finding a hanger with a nail configuration that works with the geometry. With a short steel bm., this can be difficult. It is not too late to add a ledger to the side of the beam and attach the ledger with SDS screws. You can finish installing the SDS screws once the hangers are in place so that you can assure there is no conflict with the positioning of the screws and hangers.

RE: Repairs for connecting steel beam to floor joists

(OP)
Thanks everyone for taking time to respond. I have a few follow up questions.

Is using a different hanger such as LRU28 an option we should consider as it seems to have a different nail pattern than the LUS210 hanger that was used? Any tips are greatly appreciated.

One of the pictures shows a small gap between the wood ledger and the beam flange. This is not consistent throughout but does occur in some places as I think the lumber used was not straight. Is this a concern (isn't the weight supported by the bolt in that case). How can this be corrected? Also do the bolts need to be of a specific size in this application?

Thanks

RE: Repairs for connecting steel beam to floor joists

1) Firstly, some questions too allow us to assess this meaningfully:

a) What is the joist span?

b) What is the joist spacing?

c) What is the nature of the space above the joists?

d) What is the composition of the flooring above? Tile? Concrete topping? Carpet?

2) In reality, I suspect that your situation reflects what is often the real world implementation of our pretty structural details (one example below). This stuff is just damn hard to execute cleanly.

3) I tend to be a good deal more permissive about this compared to my colleagues here. Unless the hanger's maxed out, I suspect that you'll probably be fine and that matters might actually be made worse by staging some manner of intervention.

4) To an extent, you can usually pro-rate the hanger capacity based on the number of nails that are installed compared to the number of nails required for a full capacity installation. Seems to me you've still probably got 50% - 75% of your floor capacity available here. Depending on the demand, that may be enough.

5) The plywood used for packing bothers me not at all. That's common and, really, the only practical way to fill out the space.

6) The gap between the wood fill and the beam flange may be an issue but it's hard to say. The bolts may be intended to transfer the full load to the steel beam web. As for a fix, you could pound some shims into that space or fill it with some kind of resin etc. Worst case scenario, your floor drops a 1/4" and the gap gets closed. It's not like your kids will be plummeting down a hole to China or anything.

7) Yeah, your contractor should not have modified the hangers on his own initiative.

Honestly, I've seen worse. Much worse.





HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me: http://www.eng-tips.com/viewthread.cfm?qid=456235

RE: Repairs for connecting steel beam to floor joists

(OP)
Thanks for your reply KootK.

The joists are 2x10 and W Spruce. Their span is about 12' and are spaced 16" on center.

The space above the joists is comprised of two bedrooms and 2 bathrooms (shower in one and tub in the other). The upper area is being renovated and bedrooms will have hardwood flooring (carpet previously) and tile in bathrooms.

Our engineer has asked the contractor to move the bolt locations so that they don't interfere with the hangers. For the hangers he wants to use LRU28 instead. We also checked with Simpson and they confirmed that LRU28 can be used in our case but recommend that we use SD10x1½” screws into the face flanges and SD10x2½” screws through the double shear joist fasteners.

Questions:
A few joists are not sitting flush with the beam and have as much as a 1/2" gap at the top and 1/4" gap at the bottom between end of joist and steel beam. Any concerns with this spacing?

One of the joists that needs to be supported on the beam is sistered so neither the original hanger LUS or the replacement LRU one will fit. I assume the contractor will need to find a different hanger for these two joists.


Let us know if you have any additional feedback based on the above. Thx

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