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7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

(OP)
Hello, I'm looking at a construct-ability problem.

We need a structural beam that spans 23 feet at a residential home, its fairly heavy beam for a home, w10x10 or W250x73. The problem is that we want to work indoors, and to do that we would have to cut the beam in half, jack it and do a full moment weld connection midspan.

I'm curious if there are any alternatives or concerns with this approach?

Thanks in advance!

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

If the two halves are in place - the top flange welding would most likely be very near wood floor framing above - fire risk.

You would want to have a qualified welder for the required full-pen welds.

Some kind of bolted flange plate connection could be used if there was enough clearance top and bottom - you would need to pretension the bolts so again - clearance to get a wrench up at the top flange might be an issue.



Why not use a beam stretcher?

smile

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

This sounds like yet another non-engineer trying to get easy free advice on the Internet.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

i'd cut the beam in 3rds

Quando Omni Flunkus Moritati

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

What's wrong with setting the joint on a post?. That joint then needs only a simple connection, such as a web plate bolted to each beam, enough to keep them together while joists are set, etc.. Most of these beams get set on posts whether posts are needed or not. Tell 'em there is no other way. Besides inside that smoke is hazardous. It stains everything.

I question how the house got built without the beam to begin with.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

This is usually a home owner or builder question when they are trying to accomplish a re-model or addition.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

(OP)
I'm an engineer. 5 Years of structural work on large construction, but now I'm doing construction management and haven't touched structural design in a while. That being said it is a home construction, I am adding a 100 sqft back addition to a house.

Jae: Thanks for your response. You mean fire risk during the welding process, correct? Otherwise as long as there is enough clearance a full moment connection with two welded plates top and bottom should be sufficient right?
What is a beam stretcher?

rb1957: Thats a good point, but i feel that it would add signifincat work, i'm trying to keep things cost efficient, I have thought about doing 2/3 and 1/3. That might work.

oldestguy: Maybe I didn't explain it well. its a house renovation, we are removing a wall and adding an addition. This beam is going to pick up new loads and loads from the removal of a perimeter wall (plus some roof loads).

So sounds like you all agree its is normal for a small job to have split beams? We basically want to avoid having to bring in a crane and also this allows the contractor to work from the inside in the winter (its really cold in Toronto right now)

Thank you, all.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

OK, just checking up on you.

I was suspicious because it was your first post and there is no such thing as W10x10, and if it was, that would be a very light beam.

Are you sure you need a steel beam? Have you considered parallam or glulam?

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

Was lateral Checked? jsut something that i see overlooked on nearly every "remove this wall with a wide open, 23' wide, space. Code is 20' between face of panels on CS-WSP.

That space means the wall is no longer a prescriptive BRACED WALL LINE; no longer in the residential code and you are now enter shear walls and collectors. This is an issue that I hope was addressed....?

I agree with others that bolts would be better than full-pen welds, if possible.. but welds are do-able

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

(OP)
I'm Canadian, I dont' have my codes with me. I just googled it properly, the beam is a W10 x 49. I might look at wood options again, I did some checks with Weyerhaeuser and they all needed a lot of depth I can't afford (I dont' want a bulkhead). I guess I didn't consider a glulam, but that might still have the issue of weight/size being combersom for interior work. Is a moment detail for wood beams better or worse than a weld detail for split steel beams?

No worries. :)

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

first one to make a Rob Ford joke has to buy a round in the pub!

i dislike a butt weld at the point of maximum stress. i'd nest angles and a web splice and a bucket of bolts ... but you guys don't like bolts. maybe a lap splice, instead of a butt weld ? maybe weld angles (into the corners of the I-beam) ?

Quando Omni Flunkus Moritati

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

(OP)
EngineerEric: Thanks for bringing it up, I have definately given the overall lateral bracing of the house some thought. This small wall was not providing much shear support.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

Don't use butt welds - use full pen bevel groove welds performed by a qualified welder.
Probably want to test the welds too.

Yes - fire from welding operations - be very careful as sparks get shot out and embedded in wood sometimes and smolder for hours before going off.

Beam stretcher: deflection = PL/AE. Just need a unit to pull with a very big "P" to get the delta you need to stretch across the room! smile

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

(OP)
I dislike Rob Ford butt welds as well. I like the angles suggestion in the inside corners, but I'm afried the beam might be too small to allow for proper walling in the small space... I'll have to draw up and think about it.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

Just checking! glad it was looked into.

LVL/Glulam for spans like this will weight the same as a steel beam, but they can be installed in multiple plies to reduce the lifting weight. the plies jsut get bolted together, but steel has more capacity than these for equal depth. (typically)

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

The LVL/GL options are very much cheaper and easy to work on than steel. Splicing in wood is impossible, you need an interior post. Splicing in steel will be unfeasible economically and practically IMO. You really want to get this in one piece, be it a single lam or 2 or 3.

The Weyerhaeuser software may be over conservative in checking deflection criteria, so wood may work after all. We need more info.

A W10x49 is a common column size, so you are saying you have less than 12" to work with, and would have to resort to a very inefficient beam size.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

Dacdacdac :
Why don’t you show us a cross-section through the existing wall, roof and foundation, reasonably to scale, with dimensions and loads, and complete details up at this new beam location, the info needed for a good design discussion. Maybe an elevation of the existing wall too. Then show a second section with the addition, again dimensions and loads etc. Since you haven’t done any of this construction or design, someone who has might see some options which you haven’t thought of. By the time you screw around with two sections of beam and a do proper job on the connections (welded, bolted, inspected, shored during work, etc.) your contractor can rent a crane truck or lift for a day. With that big a beam you better check your foundation conditions at its two bearing points.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

If you splice at the third points, the splices are potentially easier due to reduced moment, and might allow easier bolting.
Possibly two channels back to back for reduced weight?

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

i liked the OP W250x73 ... tall enough to do the double duty as a shear wall as EngineeringEric adroitly observed. in lieu of that, I'd definitely go with the beam stretcher.... or those new antigrav beams.

for a 23' span for a 100 sf exterior back addition, i'm envisioning a 23' of exterior wall/glass/window removed and a 4'+ room added... maybe i'm wrong, but i'd consider if alternative construction procedures as Dhengr alluded to above, might facilitate the installation of a single piece beam.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

I don't see the sense in trying to weld in a house.
A problem I'm dealing with is similar to yours, a 9m long simply-supported beam in a domestic roof.
It's a 356 x 171 x 67kg, and we're splitting it into 3 (as JStephen) and doing straight-forward splices with pre-loaded bolts.
With the cutting/drilling of the plates it may not be as cheap as welding, but probably cheaper than replacing a burnt-out house.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

(OP)
I realized that the welding does not need to occur until after we have cut the back of the house open. That being said, I'm not against bolting, I just keep hearing we wont get reliable cut outs from the fabricator for something like this... might be my contractor is not trying hard enough.

Your vision of what i'm doing is close, but its a bigger addition than that, we are adding 14". I wrongly typed it was a 100sqft addition, meant to say 1000sqft or 330 sqft per floor (including basement), I've attached a plan and section drawing.






This last one is a picture of the house right now.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

(OP)
Drawings1
Drawings2
Drawings3
Photos4

The dimensions are there. Loads are residential and roof loads (snow loads).
- FIRST, SECOND AND THIRD FLOORS
OCCUPANCY: LL = 1.9 KPa
- FLOOR LOADS: DL = 0.75 KPa
- ROOF/DECK SNOW: SL = 1.00 KPa
- ROOF DECK: LL = 4.8 KPa

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

great info. a lot bigger project than i envisioned, that's for sure.......

so, your proposed beam is at the top floor level, supporting the bedroom floor joists, balcony joists, exterior wall and roof?
and the photo is from the inside of the living room looking up?

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

As much attention as you are paying to this steel beam, pay more attention to that open deck that you have over enclosed space. I've made some good money looking at water damage to those types of structures, and a coworker just discovered they have about $20k worth of water rot damage to their relatively new home with an open deck over a lanai very similar to your detail.

Manage the water drainage or it will manage to drive you crazy...

Have you run some calcs on multiple plys of engineered wood as others have suggested? What kind of numbers are you getting?

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

I am getting 1 KPa = 48 psf, so there must be something wrong with my conversion.

Also, you say Roof Deck LL = 4.8 KPa, and Floor LL = 1.9 KPa, therefore the ratio is 2.5 which translates the same as if I used 100 psf for roof deck LL and 40 psf for floor LL in English units.

However I believe 100 psf live for a large residential deck is conservative - it should be residential floor LL x 1.5 = 60 psf.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

Also, if this is Canada, why is the snow load so small?

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

(OP)
a2mfk: I'm definitely going to give some thought on the deck details. I'm still not sure if we are going to go with a floating deck structure or duradek style roofing.

AELLC: You are right that snow load is wrong, it should be 1.12kPa (23psf), which is Toronto's minimal snow loading, at the accumulation points i believe it reaches 50psf (2.4kpa)

All: Thanks for all the advise, the more i'm looking at it the more I feel I should go with a wood framing option with a column in the middle. Probably leaving the wood post exposed. Spanning the full 7m with wood while possible would require a beam depth of 19in, a PSL 19"x5", which might also work exposed but due to the roof deck above I'm not sure that is a great idea.

Triangled: Yes to all your questions. The beam is at the top floor level, supporting the bedroom floor joists, deck joists, exterior wall and roof. Noted near item 23 on this drawings: Link



RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

Still, 1.12 KPa for snow looks way too small. The snow will drift against the wall.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

dac-

You REALLY need to hire a local struct engr. When I saw the words "beam bearing on brick wall..." that raised all kinds of red flag.

If you don't want to pay mega-dollars for a regular firm, try finding a one-person operation maybe by going online to to your Provincial Board of Registration for Engineers.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

(OP)
Thanks for the concern. I am planning on doing a 3rd party review of everything
with a colleague.

"Beam bearing on brick wall..." was an over simplification. I meant to express my concerns with the brick wall the support post are bearing on. The bearing connections will be with steel plates and proper anchorage, or a concrete bearing pocket.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

Even so, is this proper load bearing brick?
Also, with a proper brg plate the brick overall may buckle with compression load.

Overall, looking at your dwgs and pic, I still say you should invest a bit in a licensed PE or SE

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

Snow load (unmodified and unfactored) for toronto is actually 0.9kPa, special consideration would have to be taken here for snow build up on the balcony. Lateral bracing requirements would probably be minimal since it's an upper storey.

Have you considered hanging the existing joists from a new timber beam (most likely a couple of LVLS)? This would greatly reduce your bulkhead and in-fact since you will have a 'step' directly above (for the balcony door) you can use that additional space to your advantage. You'd have to jack the existing floor and reduce the length of the existing joists. A timber beam would not require any machinery for placement.

Cutting up a steel beam will still leave you with extremely heavy lengths so you are going to require a machine to place it regardless.

I can size the beam for you according to the OBC, i'm in the GTA.

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

Your beam will only be as good as the weld... and welding it in the middle will be near the location of maximum stress.

If you can get half the beam in place, you may want to consider cutting the one half length into half again. This gives you twice as much weld as two pieces and the welds are located at quarter points... likely in a region of lesser stress... you may not need full penetration welds.

Dik

RE: 7 meter (23 feet) beam - simply supported - split in half and then welded on site - Any Concerns?

You could also do a bolted moment splice if you can afford the extra depth for the plates and bolts.

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