Hi there. I need to know if the steel frame I have constructed will
support my house when I move it. I have taken 4" structural steel
(A36) I-Beams and welded them together to join them into a box beam.
The total width of the flanges (top and bottom) is now 5". I then
welded a rectangular shape to put under the perimeter sill of the
house after I raised it off the concrete footing (in place of the
footing. Next, I welded two 36' long I-beams longitudinally, spaced 8'
apart down the center of the building (to support the middle). I plan
to take two 20" by 30' I-Beams and place them 90 degrees from the
other beams (crossways). After welding these beams to the frame, I
intend to lift the building on the ends of the beams with two 40-ton
picker trucks (spreader bars) and place the building on a trailer for
removal.

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Request for Question Clarification by redhoss-ga on 18 Nov 2006 06:54 PST

Is your house a one storey structure. Does the foundation of the house
consist entirely of the perimeter concrete beam with no support in the
center portion. What is the spacing of the two 20" by 30' beams.

Okay steelrules, I will just make some likely assumptions and we will
see what happens. I will assume it is a one storey house, no other
support than the perimeter beam, and a 12' spacing on the spreader
bars. If any of this is wrong, we can make adjustments.

Your 4" beams sound like S4x7.7 which has these properties:
S = 3.04 in^3
I = 6.08 in^4
The way you have fabricated your box beam creates a section with double strength:
S = 6.08 in^3
I = 12.16 in^4

I will guess that your house might weigh something like this:
Floor = 15 psf
Roof = 20 psf
Walls = 20 psf

Total = 55 psf

So, we would have a cantliever loading on two of the box sections plus
the two center beams (I assume they are also 4").

M = wl^2/2 = (55 x 24)12^2/2 = 95,040 ft-lb = 1,140,480 in-lb

S required = 1,140,480 in-lb / 19,800 psi = 57.6 in^3

Your total S = 3.04 x 2 + 6.08 x 2 = 18.24 in^3

So, that won't work.

It would be better if the spreader bar was longer. The optimum length
would be 18'. Then we would have:

M = wl^2/2 = (55 x 24)9^2/2 = 53,460 ft-lb = 641,520 in-lb

S required = 641,520 in-lb / 19,800 psi = 32.4 in^3

This still does not work and we have not even considered deflection.
Deflection would be important to prevent damage to the structure. I am
afraid that myoarin-ga is correct.

Have I missed something. Do you have another idea about how to use
your available materials. Please ask for a clarification and we can
take another look. Now I am going to watch some college football.

Redhoss

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Request for Answer Clarification by steelrules-ga on 18 Nov 2006 22:00 PST

Thank you for your answer. You guessed the beam size exactly. Yes it
is a one storey house. Yes, there is currently a laminated centre beam
down the middle of the 24' wall down the 12' centre line. The two
centre beams 4' on either side of the centre line are supported by
3@4" by 8'I-beams, joined crossways to the two centre beams at 12'
intervals along the 36'length (I thought this would support them
against deflection). The two 20" by 30" I-beams are spaced crossways
also. I plan to put them crossways under my frame (welded to it so it
won't slip off) 8' in from the ends of the 36' side of building). The
picker truck has 24, 30' spreader bars for the lift. Do you need more
information? Sorry I didn't mention the extra details.

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Clarification of Answer by redhoss-ga on 19 Nov 2006 08:21 PST

The 30' lift beams being spaced 8' from the ends rather than 9' as I
proposed will help if you can support the resulting 20' span between
the beams. Do you possibly have another 30' beam you could
chain/attach to the spreaders close to the center of the span. Also,
you never said if I was correct in assuming that the perimeter beam is
concrete. The reason that you would need to be very concerned about
deflection is that a concrete beam while strong in compression is very
weak in bending. I am not an expert in moving houses. I would guess
that there would always be some damage to sheetrock that has to be
repaired. Also, the perimeter beam (assuming concrete) probably has
some cracks even before the move. Am I correct.

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Request for Answer Clarification by steelrules-ga on 19 Nov 2006 10:35 PST

Yes I can probably find a 30' beam for between the span of the
spreaders. I am not lifting on a concrete perimeter beam. I have
raised the house at the mudsill, fabricated the frame and slipped it
under the sill. I the bolted the sill to the frame in the same holes
used to attach the sill to the concrete foundation with lag bolts.
Therefore, all lifting is done on the steel frame. There are no
concrete beams. And yes, there are some cracks in the sheetrock. I
attribute those to when I started jacking the house and sill off the
foundation and discovered I was still attached to the old farmhouse
next to my building. These cracks are only minor.

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Clarification of Answer by redhoss-ga on 19 Nov 2006 11:22 PST

I think that you will have a successful lift. You sound like a very
well informed and skillful person. With the addition of the extra beam
your frame should do the job. I hope that any additional damage is
minimal. Good luck.

THis is just a free comment.

I think we need to know a lot more about the building: type of
construction, size besides horizontal measurements.

Four inch I-beams supported at 24 and 36 ft seem too likely to sag
from my very non-expert view.

Where is Redhoss-ga, the expert for the subject?

Redhoss,
I hope your team won.  
You raise the - for me unlikely - possibility that the house is only
supported by the perimeter foundation.  If this were the case, then
Steelrule's frame MIGHT work, but I still have very great doubts.  The
moment you move something like a house, the structure is likely to be
stressed in ways it wasn't built to take.
If the frame is not entirely rigid under load when being raised and
moved, such stresses will occur.  And then the house has to be moved
on the trailer and be unloaded on its new foundation.

I am not questioning your calculations  - which I don't understand - 
just suggesting that the frame has to be a great deal more substantial
to remain entirely rigid when it is picked up.

Anyway, you have already answered the question in the negative.  It
just occurred to me that the task does not call for a frame that under
ideal conditions can carry the house, but rather for one that provides
an absolutely rigid 24' by 36' substitute for the foundation during
transport, a small earthquake.

Cheers, Myoarin