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LVL or steel I BEAM?

 
 
Reply Fri 30 Mar, 2012 07:13 pm
Im building a buiding for my new studio/garage/office/RV holder. Its a 2 story building and its 68 X 38 . Its a "T bone" construction and the roof will be a 12 pitch with 2 shed dormers. Inside of the larger bay will be 36 X 56. The axis of the roof is along the length and we will be spanning 36 feet inside. Ive designed it to hasve 4 central pillars to hold up a central span beam andthe beam will either be LVL (3.5"X10") or a steel 9" I beam. What would any of the A2K builders reccomend?
LVL is more expensive than an I beam and will probably be softer on the travel on the upstairs floor, whereas a steel beam seems stronger to me.

ANY suggestions will be appreciated. Thanks
 
Rockhead
 
  1  
Reply Fri 30 Mar, 2012 07:42 pm
@farmerman,
I'd go steel, but I overbuild everything I make...
0 Replies
 
ossobuco
 
  1  
Reply Fri 30 Mar, 2012 07:44 pm
@farmerman,
Listening. I've an I beam bias but not qualified to give a useful opinion.
Got any structural engineer pals/associates? Aside from work projects I've hired structurals a couple of times for not all that much money to either review my drawing or inspect a house.
roger
 
  1  
Reply Fri 30 Mar, 2012 07:45 pm
@ossobuco,
I bet Panzade and maybe twopacks has an opinion.
ossobuco
 
  1  
Reply Fri 30 Mar, 2012 07:48 pm
@roger,
Fer sure.
0 Replies
 
Ceili
 
  1  
Reply Fri 30 Mar, 2012 07:49 pm
I'd go LVL it's very strong and beside being cheaper and lighter, it'll be easier to work with or modify - should the need occur.
Ionus
 
  1  
Reply Fri 30 Mar, 2012 09:27 pm
@farmerman,
Structurally there is no difference if you have done your homework and they will both handle the load . With wooden posts, a LVL will look better but will probably be more expensive . However I beams and steel posts can be boxed in for even greater expense . Without me ringing your supplier, are you sure you can get a 9" by 36' I beam ? It seems an odd size . Just going by your description I initially thought you would be spanning the 56' thus giving you two equal size bays of 18' by 56' . I take it you will have 5 equal size bays of 36' by 14' ? So you will have four beams ?
farmerman
 
  1  
Reply Fri 30 Mar, 2012 09:45 pm
@Ionus,
Hey your back. (I had you on ignore I thought it was spendi). Wel the Beam would run in the middle of the 56" length dividing the 36 span into two lengths of 18.
The I beams will be probably be 3 18+ footers so theyd top the columns (brick columns on spread footers) If its a sereies of I beams, they would be bolted together at the column edges and overap about a foot.
As you said the LVL is actualy more expensive.
I was worried about how either would feel underfoot. Ive pretty much overdesigned(yeh me too Rocky) becase Ive got heavy scissors trusses for the room and Im sure they could span the 36 feet but I dont want ANY spongy feel for such a big floor. Ive been in buildings where the span was done ok but I can feel that trampoline effect.

Will the steel feel too hard underfoot or will the LVL feel too spongy. Maybe Im worried too much over nothing but I dont wanna have the damn thing bug me for the next (whatever) years knowing that I could have got it answered here.
farmerman
 
  1  
Reply Fri 30 Mar, 2012 09:49 pm
@Ionus,
No bays, its all one big room downstairs and up. The only real bay is the entire additional T bone section of 12 feet wide and about 42 ong. This has its roof axis at right angles to the other section and will house an RV as a garage.

This is gonna be neat and Im doing a lot of the work but all the framing and the concrete is veing doen by an AMISH guy whose a genius at building but is noncommital about I beams. He is a big LVL guy .
0 Replies
 
farmerman
 
  1  
Reply Fri 30 Mar, 2012 09:54 pm
@Ceili,
ACtually the LVL is more expensive here. Its 3.5 thick (actual) and is a glue beam thats like one bigass hunk of plywood made into a beam. I suppose it may be easier to work but Im concerned about its comfort and whether itll last as well as an I beam.
Which will never be boxed in cause I want to use the beam for an anchor for a chain hoist
0 Replies
 
farmerman
 
  1  
Reply Fri 30 Mar, 2012 10:06 pm
@roger,
I hopepanzade shows up.
Osso, glad to have you for support.

Rocky- I hear you, maybe thats my problem (overdesigning) I know I didnt need the columns but what the hell its not ike the room is too small.
We were digging column footers today and I got about 10 oads of good clen fill from a buddy who is building a golf course about 16 miles nearer LAncaster and He called me yesterday and asked if I knew anyone who needed fill for FREE and delivered on a series of triaxles. Talk about dumb luck.

There was an old building there where the new one is going and I had it ripped down and hauled away free by the AMish who dont waste a thing. The whole damn building was recycled including the old concrete block and floor which was pulverized using a track hoe with a jackhammer on the backhoe end. Al thatw was taken by two AMish brothers who are building a road base to their new dairy barn. The old aluminum siding was sold to a scrap delaer as were the old windows. The tin roof was sent to a metal recycler for specialty metals and the woode was reused by everyone incuding some by my guy to make forms for concrete filing in the new cinder block foundation.
The reason the opld building was totalled was because its foundation was done by some amateur (it was above frost line so it was heaving and there was no way I cpould put on a second foor) That building was dangerous and could have fallen down ( I strapped angle stays around two corners of the back walls)
demonhunter
 
  -2  
Reply Fri 30 Mar, 2012 11:57 pm
@farmerman,
I actually know the answer to this cuz i wuz a carpenter. not gonna answer though. TROLL
0 Replies
 
Ionus
 
  3  
Reply Sat 31 Mar, 2012 12:49 am
@farmerman,
Your joists will run the 18 span then . No problems there .

The floor feeling spongy will be a function of the thickness and spacing of the floor joists and the thickness and spacing of the floor boards . Your local timber merchant will tell you what sizes are available (it will be different to here) and will probably have a good idea for spacing . Tongue and groove will help make it more rigid . If the floor is designed properly, you will not know whether it is LVL or I beam underneath . Depending on the thickness and depth and span of the joists, 450 centres should be strong enough .

Might I suggest a cost saving measure...put down a particle board floor and then put a 10mm hardwood but-joined surface on top . It is actually slightly more expensive but you get good rigidity from the particle board and good appearance from the hardwood . The hardwood can be sanded and polished without ever interfering with the minimum thickness of the flooring, and it can even be replaced if need be . The rigidity is far greater than you would get any other way, so there are some benefits to be considered . Disadvantage is that if you can see the underside you might want to paint it although if varnished to show off LVL and wooden posts it has a pleasant cork like appearance to it . If you go for the I beam, then you will probably want to paint it anyway .

There is nothing wrong with worry before a project . It alleviates a lot of worry after .
farmerman
 
  1  
Reply Sat 31 Mar, 2012 08:36 am
@Ionus,
we are aying T&G barn flooring upstairs. Its 1 3/4 " thick and 8" wide . I didnt think about the use of OSB on the underlayment. That might just work and give an additional rigidity. were doing 16" centers on the joists.

In addition my central columns are there to assist in laod carrying . The building is concrete block up to the windowsills and then baoon frame thereup. The columns are additional "Tornado proofing" since we only get cat 1's or lower whenever a twister comes around here so we may lose some roof but it wont send my building all over the county.
I did have an engineer buddy do a load analysis on the building shape but I didnt ask him about the floor. I only came up with having this decision in the last two days.
Fido
 
  1  
Reply Sat 31 Mar, 2012 08:42 am
@farmerman,
If flex is the issue, and it often is, you do not want to exceed twice your depth in inches on the I beam in feet of span... A five inch I beam, if such a thing is made would be good for a span of ten feet, but then you have to ask if that is good for the load of joists on it, etc... I do have the structural steel manual for more detailed information... From my reading I would say that a heavy eight inch wide flange should be all you need for center span, but consider that you will need a nailer on top of that, and like a sill seal because inspectors do not like wood on steel because condensation can cause some rot, if that is an issue, but mostly the means to fasten your joist so they are tornado proof is a good idea...
farmerman
 
  2  
Reply Sun 1 Apr, 2012 04:27 am
@Fido,
I think we are gonna go with the steel beam. (ightning protection will have us ground cable it at each end) and it will deflect less than the LVL according to the Mfr tech notes I got.

The I beams we get are already set up for nailers and have one side coated with tyvek or like so I suppose thats for moisture.
0 Replies
 
panzade
 
  1  
Reply Sun 1 Apr, 2012 10:08 am
I've retired from the construction business and don't even think about that crap.
You got some good advice here FM, now go out and Get "R Done.
0 Replies
 
parados
 
  1  
Reply Sun 1 Apr, 2012 10:19 am
@farmerman,
Quote:
I did have an engineer buddy do a load analysis on the building shape but I didnt ask him about the floor. I only came up with having this decision in the last two days.

You might want him to do an analysis if you are planning on lifting anything heavy with the chain hoist you will attach to the beam. The floor might not like it if you start flexing that beam during heavy lifts.
farmerman
 
  1  
Reply Sun 1 Apr, 2012 11:54 am
@parados,
well the beam will rest on several columns throughout its length. Its actuay the ability of the beam (or LVL) to damp any sponginess in each of the three sub segments of the floor > Each of these subsegments are 18' a side and about 19 ft each segment. The roof peak for that segment which ahs the two floors will be paralleling to the beam
raprap
 
  2  
Reply Sun 1 Apr, 2012 07:36 pm
@farmerman,
I like LVL's as an alternative engineered structure, they're easy to work with, lighter than steel (no crane may be necessary to place) and they finish well--

Recommendations--treat the loading as a simple beam with supports at the ends---your design dead loads are normally around 50 lb/ft^2 per floor section (unless its reinforced concrete then use 100 lb/ft^2) and your design live load is about the same (50 lb/ft^2) unless its a warehouse--so if you've used this for sizing the beams for a nominal maximum deflection of 1/360th the span your bending loads are acceptable.

Don't forget the shear--to do this use the same loading at the supports and divide this by the area of the beam section. Shear is the second order effect that can bite you in the ass. Normally a LVL beams acceptable shear is an order of magnitude less that a steel beam of equivalent bending moment, but unless your second floor is a concrete slab I would doubt this would be a consideration.

Rap
 

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