Beam Recommendation

[akpolaris]

I need to find an I Beam or H Beam to support a deck in a residential building. the deck will be 24' X 12'. One 24' side will be secured to a 2" X 12" ledger on the exterior wall inside the building. The side with the steel beam will be a clear span of 24'. I am looking for a load of 65# per sq/ft. Is there a reference that I can find with out pay an engineer to determine what the specs of this steel should be. I am wanting to consider the steel vs. a glue lam beam
thanks
Tom

 

[laser3kw]

steel is forever - wood is temporary -rots out in 5 to 10 years.

I am looking for a load of 65# per sq/ft

that would be static load. Consider a bunch of people dancing and jumping around. You could end up with a trampoline if not done correctly

 

[csp]

Sounds like this is indoors.

 

[kwb]

9300lb distributed load On a 24ft span - something like a w12x25 but I am posting from phone, away from my spreadsheet, and drinking.

 

[akpolaris]

Drinking is good. it is the weekend. W12 X =25 that isn't the flange and dimensions is it?

9300lb distributed load On a 24ft span - something like a w12x25 but I am posting from phone, away from my spreadsheet, and drinking.

 

[DekeT]

W12 X =25 that isn't the flange and dimensions is it?

 

[kwb]

W12x25= wide flange 12 in depth 25 lb/ft.

I may be drinking but Google could help if you want to speak in terms of structure steel.

 

[DekeT]

W12x25= wide flange 12 in depth 25 lb/ft.

I may be drinking but Google could help if you want to speak in terms of structure steel.

Is giving engineering advice under the influence similar to driving under the influence?

 

[JCByrd24]

In this case it's like driving under the influence but with a flashing warning sign that says I've had a few. The guy wants free advice and he got it and knows the circumstances. By the way it (actually w12x26 is standard not 25) looks good to me too, I've had one beer.

Laser, all floors are calculated with loads statically even though actual loads are "live", and the OP hit the mark pretty well on his spec as long as he doesn't want it both loaded with snow and people or something else at the same time. The trampoline effect is much more likely to come from the joists than a steel beam anyway. To avoid it look at L/480 min or better yet L/600 under deflection for 40-50 lb/sq ft live load in joist tables/calcs. AWC has a very handy one online.

I do agree though that steel is likely better for this span.

 

[akpolaris]

thank you mr byrd. I know that I am seeking engineering advice on line from possibly questionably qualified unknown sources. That exposes my typing skill to the world. a standard static load is 50# per s/ft I believe. Routinely this is the static load on a floor or deck to support a small residential apartment. I get lost looking at the mathematical formulas to determine the steel I need. I can use a 6" X 16" glu lam but want to compare cost of steel. I can stiffen the steel but boxing it or plating the flange. I am just looking for s starting point

 

[Nor'Easter]

Don't know your regs and codes in Seward but out here if a beam failed and I told the insurance company "Ya see some guy here on this website said it'd be fine", well that wouldn't fly.

My point being cover your *** and get your plan stamped. Cheap insurance.

 

[JCByrd24]

Don't know your regs and codes in Seward but out here if a beam failed and I told the insurance company "Ya see some guy here on this website said it'd be fine", well that wouldn't fly.

My point being cover your *** and get your plan stamped. Cheap insurance.

I believe this is simply not true in a residential setting. My wife and parents both work in insurance and one thing I've heard regularly is "we do insure stupidity". There are a few particular things most HO policies don't cover, other than that it's pretty fair game. For example, if you don't clean your chimney and have a chimney fire, it is usually still covered. I've never heard of a policy referring to construction requiring stamped plans. My dad will visit a house before writing a policy and take pictures etc and the company will decide of it looks like a bad risk, they don't ask for plans/drawings though. You can always read your policy.

AK, with regard to beam stiffness, do not worry about stiffening it. That beam even when loaded will not bounce. The joists will be the issue. You do need to worry about properly supporting it on the ends, potentially boxing it at the load bearing points, and also laterally (the joists should not just rest on top) they should tie to it somehow to prevent the top flange from buckling.

 

[akpolaris]

No codes where I live at but the plan is always to build stronger than code directs.

Don't know your regs and codes in Seward but out here if a beam failed and I told the insurance company "Ya see some guy here on this website said it'd be fine", well that wouldn't fly.

My point being cover your *** and get your plan stamped. Cheap insurance.

 

[akpolaris]

I understand all that. The floor joist will be 2" X 12" or suitable TJI's. and set into the beam, boxing it in securely. My entire goal with the question was to get a beam spec. Free engineering advice if you will. If I don't like or agree with the advice I can ignore it. Casting a question out for brainstorming or idea sharing can often present concepts the OP had not considered. I have no residential building code in my rural area so I try to build anything code + if you will.

I believe this is simply not true in a residential setting. My wife and parents both work in insurance and one thing I've heard regularly is "we do insure stupidity". There are a few particular things most HO policies don't cover, other than that it's pretty fair game. For example, if you don't clean your chimney and have a chimney fire, it is usually still covered. I've never heard of a policy referring to construction requiring stamped plans. My dad will visit a house before writing a policy and take pictures etc and the company will decide of it looks like a bad risk, they don't ask for plans/drawings though. You can always read your policy.

AK, with regard to beam stiffness, do not worry about stiffening it. That beam even when loaded will not bounce. The joists will be the issue. You do need to worry about properly supporting it on the ends, potentially boxing it at the load bearing points, and also laterally (the joists should not just rest on top) they should tie to it somehow to prevent the top flange from buckling.

 

[volleyball]

I would get someone to engineer this. The cost involved in material for overbuilding or retrofitting a substandard deck may be more.
I would Consider 2 steel beams the 24' length with 2 x 10's between. No steel at the far end.

 

[laser3kw]

Laser, all floors are calculated with loads statically even though actual loads are "live", and the OP hit the mark pretty well on his spec as long as he doesn't want it both loaded with snow and people or something else at the same time. The trampoline effect is much more likely to come from the joists than a steel beam anyway. To avoid it look at L/480 min or better yet L/600 under deflection for 40-50 lb/sq ft live load in joist tables/calcs. AWC has a very handy one online.

I do agree though that steel is likely better for this span.

got it! good to know. Obviously, I am not a structure engineer.
at least I got the steel part right

 

[gasgas17]

Most places that sell structural steel will engineer free of charge if your buying the steel from them. Same goes for wood products.

 

[akpolaris]

That has not been my experience. It is exactly the opposite. All salesman have referred me to an engineer. Contractors on the other hand generally will discuss the materials and methods that they would use to assemble a project. In a small town like where I am that is the best advice. Call 2 or 3 builders to look at the job and ask for a bid and how they will do it.

Most places that sell structural steel will engineer free of charge if your buying the steel from them. Same goes for wood products.

 

[volleyball]

I would not piss off the contractors in my town by asking for bids and how they would do it , then copy their idea. At least offer to pay for them to design you job.

 

[Nor'Easter]

I would not piss off the contractors in my town by asking for bids and how they would do it , then copy their idea. At least offer to pay for them to design you job.

Anything you get from a contractor will have been done after he was told by the engineer it was ok to proceed as designed.

Don't try to work around the engineer, really. I've seen some sketchy stuff..

 

[volleyball]

If there is no building requirements, why would it have to be done that way? Most likely a builder would design/build on there own.
Just like a homeowner would do with a deck a foot off the ground in there own back yard.

 

[kwb]

A deck a foot off the ground is probably going to have a lot of posts and small lumber as "beams" not spanning more than 6-8'.

A 24' span is being done for a reason - usually to make a big open space underneath the deck at ground level.

This means the people on the deck are in much greater risk because they are probably at least 8' off the ground.

 

[akpolaris]

Interesting discussion

 

[akpolaris]

What I am not able to determine is what the allowable loading on the beams would be for that span. For example would a W10 X 22 suffice? It is lighter, so cheaper in cost, and with the short 12' span may be sufficient for my purpose

 

[kwb]

Most of the time deflection is the one to watch for. I like things to not be bouncy so I typically will start with L/480 and then play with things from there.

Deflection is a cubic function of Length - meaning that cutting span down just a little can often make a big difference.

I am not going to engineer this on a forum and I am not Licensed in AK. My first post in this was intended as a ballpark sort of size to give a feel for what you would be dealing with. If you half the span you probably get away with something a lot lighter than a W10x22 and wood makes a lot more sense.

With a third post you also make it a lot easier to brace for lateral/shear considerations. Height of the deck plays into how much bracing would be required with your selected post sizes and post/beam connections.

 

[akpolaris]

At the very least this has caused me to do some engineering type research and learned a bit about classification of steel beams. This is a clear span without posts, supporting a mezzanine which can be storage or an apartment. I don't want any posts in the shop because I will damn sure hit a post with a wheeler, snow machine or truck if given the chance.

 

[bczygan]

So this isn't a deck on a house, but a mezzanine in a pole barn or steel building?

A couple of things.

I assume you are using 50#LL and 15#DL.

You mention a GLULAM. We haven't used them for anything except arches in churches for forever. We use LVL's for this kind of thing. Hope that is what you mean.

If it is indeed a mezzanine, then the constraining factors are usually (In order of importance), height, clear span and load carrying capability.

The more you want to optimize any and all of these, the more expensive the materials become.

The advice above to limit deflection by using L/480 is good advice to get a stiffer and less bouncy feeling floor.

In general steel will get you less deep members, maximizing height.
If you do decide engineered wood will work for your loads and spans, then choosing a stronger version will maybe allow less depth in the member and better height.

The ledger is a beam as well. It supports half the load. Carefully engineer it's size and connection.

For the wood joists. placing them closer together and using lumber species with better values will allow less depth, if that is needed. Engineered joists may also solve problems here.

Bill

 

[Nor'Easter]

If there is no building requirements, why would it have to be done that way? Most likely a builder would design/build on there own.
Just like a homeowner would do with a deck a foot off the ground in there own back yard.

Then why not just use a couple o' 2x6s nailed together and call it a day? Forget the trouble of beams entirely.

We did a timberframe garage with a second story and cleared 24' on the first level, it can be done with wood no problem, sometimes cheaper too. Depends on where you get your materials.

 

[akpolaris]

thanks again for the insight /materials referencing