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I am working on a project that has three 2x12’s supporting a load of 12,000 lbs. similar, but not exactly, to how joists support a house.

The 2x12’s are supporting about 6,000 lbs. on each end.

The three 2x12’s are: a) Each cut to 90in.

b) The load takes up 24in. from each end of the 2x12’s leaving 42in. of free space in between.

c) The three 2x12’s are spaced parallel to each other, with one 2x12 being 24in. in front of the other.

d) The 6,000lb. (On each side) load is laying on a thick wooden plank (on each end) that is perpendicular to the three 2x12’s.

e) The two thick wooden planks on each end of 2x12’s (mentioned in “d”) is securely fastened to the 1.5in. part of the 2x12’s, as well as having blocking and other bolted wooden members that leaves (as stated in “b”) 42 in. Of free space in between.

f) The three 2x12’s are only 12in. off the ground.

Everything is stable and strong without any issues except for one.

I need to lift this so that it is 14in. off the ground (lifting it 2 in. in total).

Removing the load; as well as dissembling is not an option.

This will have to be lifted with the three 2x12’s and everything above (including load) remaining intact.

My best option is to lift (with a hydraulic jack) the front most 2x12 to 14in. and then lift the back most 2x12 to 14in. -I’ve done this before with no problems.

The only problem, that I have now, is that directly under the 2x12 is things that I can not remove and is not strong enough jack it from.

The saddle of the jack is 2in. All wood is Douglas Fir #2 or better.

My plan is to bolt a 4x4 cut to 42in. (to fit in the free space mentioned in “b” and to better distribute the force of the jack).

This 4x4 will be bolted (3 bolts spaced almost equally apart) to the outward face of the 11.25in. part of the front most and back most 2x12’s.

Questions:

  1. Do you think is strong enough to support the load plus force of the jack or do you think it will just rip the 4x4 off of the 2x12; while also destroying the face of the 2x12’s?

  2. Do you think maybe adding a 4x4 on the inward faces of the 2x12’s (these will not have the jack touch it) will provide any more strength to make this process acceptable?

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    $\begingroup$ a sketch would be great. $\endgroup$
    – kamran
    Nov 27, 2020 at 1:06
  • $\begingroup$ I do not understand what you purposed to perform the lift now - what is "the thing" below you can't jack it from, how do you intend to avoid it in the changed lifting plan, how exactly the 4x4 to be utilized, can you lift from above??????? Show a diagram/sketch as suggested will help. $\endgroup$
    – r13
    Aug 24, 2021 at 12:54

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In the absence of detailed information and assuming that the existing fasteners and connections are strong enough just as an illustration and with the understanding that this is not advice, I would consider using 4 Simpson Strong-tie fasteners with, uplift rating of $12000/4= 3000lbs\ 3000*1.5= 4500lbs$

Using 1.5 safety factor we look for a fastener with the 4500lbs uplift rating from Simpson's fastener online calculator here.

Simpson fastener selector

This is a picture of a similar fastener. By the way, you made a mistake and posted your comment as an answer.

fastener

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