How to properly retrofit a too short floor truss... 1

[XR250]

The picture says it all. Ironically, no floor sag!

 

[azcats]

I think you could have come up with a better detail.

 

[oldestguy]

"Ironically, no floor sag! " YET

 

[XR250]

I think you could have come up with a better detail.

No, I feel that detail is ideal

"Ironically, no floor sag! " YET

Been there 20 years. The redundancy of wood framing is pretty humbling.

 

[KootK]

Truly, I don't feel that it's that far off. Done from scratch I would:

1) do it symmetrically on both sides.

2) use a ripped LVL or something to match the truss depth.

3) get enough screws into the truss flanges that the small amount of moment was developed.

4) get enough screw into the last vertical web that the shear is transferred out to the reinforcing.

It's probably the last one that'll getcha'. And, of course, I'd be taking the reinforcing back a good 4'-6' regardless of what the numbers said.

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

 

[XR250]

@KoootK

I agree on your analysis.
Fortunately, it is getting cut out for a stair opening. Otherwise, I would simply sister it with a 14" LVL.

 

[KootK]

Oh... so you weren't actually asking how to properly repair the floor truss. Boo for trickery.

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

 

[XR250]

Oh... so you weren't actually asking how to properly repair the floor truss. Boo for trickery.

Oh sorry for the confusion. I was just giving you guys something to smile at.
I'll be more careful next time.

 

[JAE]

Can you provide a photo of the sky-hook above that floor truss? I'd love to see it!


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[OldBldgGuy]

I think you guys are all missing what's missing. There was a partition under that truss and the block you see was simply filling in the triangular gap beyond it. Whether or not intended, the partition carried the truss.
The end stud of the partition is still there, the top plate was cut off and still intersects the other one, and the toenails into the top plate are still in the truss.

 

[Ron247]

Highly conservative splice. Has 2 "strength knots" in the lower portion. Ever try to nail in a knot? They are tough. Builder made sure he only put a member on one side. Putting a member on each side would have caused the forces to split apart near the end to go to each side equally. That "splitting" of the forces may cause the wood to split too. Always remember Load Path. Shrewd.

I zoomed in and do not see any evidence of overnailing. Overnailing can destroy a precise connection such as that. One nail is all I see at the top and possibly one at the bottom. I guess an 8d box nail was not conservative enough so it looks like a 16d was used. Possibly wasteful.

Splice not tall enough? Add that 2x2 and possibly a 1x2 at the top to match existing. Solid LVLs are highly over rated. It is better to use scrap lumber rather than new material. Build Green!!!!

And lastly, the lap length. Basic rule of thumb, the lap length in inches should match your IQ divided by 3. So a 4" lap means, damn, no calculator available. Based on my guzzindas, that would be 12.

But I am really sure it withstood the Billy Joe test. (my apologies to any Billie Joes in the thread). Billy Joe stomped it with his right foot one time and it did not collapse.

 

[KootK]

I think you guys are all missing what's missing.

Crap, you might be right! I see it.

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

 

[Ron247]

Good catch OBG. Looking in detail helps a lot. Now the question is, when was it removed. Now I feel bad about my post. Not really.

 

[Ron247]

Looking closer, the 2x12 does not look like it was original. It looks like the reinforcing was caused by the wall removal. There are not any drywall fasteners in the block. On original construction, there would not have been a need for it. The plywood joints would not align on the blocks and the end band was close enough to support the floor deck without the block.

 

[XR250]

Yea, excellent observation OBG. I believe the wall must have been removed a few days ago during demo. I was not that familiar with the project to know the original conditions.

 

[milkshakelake]

It is better to use scrap lumber rather than new material. Build Green!!!

Can you explain that? How would you know the capacity of old wood? I would love to use old materials but I don't know their capacity per NYC Building Code, to the satisfaction of a building official.

 

[Ron247]

milk: it was a joke

 

[milkshakelake]

@Ron247: LOL my bad, I fell for the sarcasm