Span ? - 21' open

[ddurrett896]

Stating my garage next month and have a span question.

My garage has a gable roof, however the opening won't be on the gable side. Will be on the side that has the rafter tails.

At 21' with 6/12 trusses 26' long, I will have 11 trusses resting on this beam. My local lumber yard said double 24" will work. Looking into an option for 14" or 16" tripled to save some head room.

Anyone know what a Steel I beam will hold? I've got suppliers that sell them, but don't do much on the engineering side for loads, etc. Attached is a picture of the load info. Thanks for the help!

 

[matt_i]

I put in the I-beam. It was a mountain of work due to having to fabricate all the connections back to wood. I saved 4". I still have the I- beam and its engineered for more which is a plus. You also have to ask yourself if your welding skills are enough to entrust to this the structure.

If you look at Ixx which is a cross-sectional resistance to bending, for a double 24 vs a triple 16, its not even close. 4032 in^4 for the double 24 and 1792 in^4 for the triple 16. I'm using a width of 1-3/4" for a LVL.

 

[ddurrett896]

I put in the I-beam. It was a mountain of work due to having to fabricate all the connections back to wood. I saved 4". I still have the I- beam and its engineered for more which is a plus. You also have to ask yourself if your welding skills are enough to entrust to this the structure.

If you look at Ixx which is a cross-sectional resistance to bending, for a double 24 vs a triple 16, its not even close. 4032 in^4 for the double 24 and 1792 in^4 for the triple 16. I'm using a width of 1-3/4" for a LVL.

So you went with an ibeam. What would work in this case?

 

[matt_i]

Its not a trivial analysis to just say "use this size". One has to consider the 2nd floor (attic truss?) loads, you have to consider the snow load and the dead load of roofing plus some safety factor. The top flange has to be fully braced (connected to each truss) and has to have an uplift connection, which is again a metal-to-wood connection

 

[Samh]

Stating my garage next month and have a span question.

My garage has a gable roof, however the opening won't be on the gable side. Will be on the side that has the rafter tails.

At 21' with 6/12 trusses 26' long, I will have 11 trusses resting on this beam. My local lumber yard said double 24" will work. Looking into an option for 14" or 16" tripled to save some head room.

Anyone know what a Steel I beam will hold? I've got suppliers that sell them, but don't do much on the engineering side for loads, etc. Attached is a picture of the load info. Thanks for the help!

Have you considered 2 smaller doors instead of 1 large door?

 

[ddurrett896]

Re: Span ? - 22' open

Have you considered 2 smaller doors instead of 1 large door?

So this is going beyond my garage door. Because of setbacks, the Garage will be shaped like a capital L.

the smaller part of the L is 12' long by 22' wide. I want to pull a car in part the 12' mark without a pole in the middle of the garage. In order to achieve this, I have to span that full 21".

 

[firebirdparts]

If you have the live and dead loads, the analysis on the beam size is pretty simple. it's just a uniformly distributed load. A person in the business of selling steel would do all the welding for you around here.

So it's not a difficult analysis, but you probably should ask for a competent person to do it. It's going to take 30 minutes.

 

[mike93lx]

Its not a trivial analysis to just say "use this size". One has to consider the 2nd floor (attic truss?) loads, you have to consider the snow load and the dead load of roofing plus some safety factor. The top flange has to be fully braced (connected to each truss) and has to have an uplift connection, which is again a metal-to-wood connection

Craziness.

Its almost like their are professionals that do this stuff and can provide the right specs with insurance and training to back it up

 

[lakeroadster]

The attachment you provided doesn't account for wind loading?

Virginia Beach.. shouldn't there be hurricane loading there?

I'd suggest contacting a structural engineer.

Good luck with your project.

John

 

[yeldogt]

Don't you need stamped plans in VA?

Any live loads above? If so be very careful as often the minimums will get you lots of movement.

I would never do this w/o a structural engineer looking at it --- ask you inspector if he knows any retired in the area. great way to get architects and engineers for small jobs

 

[ddurrett896]

Don't you need stamped plans in VA?

Any live loads above? If so be very careful as often the minimums will get you lots of movement.

I would never do this w/o a structural engineer looking at it --- ask you inspector if he knows any retired in the area. great way to get architects and engineers for small jobs

Don't need stamped plans for the entire project. A generic wall brace plan and a stamp for the trusses gets passed. The variable I've never dealt with is the large span.

Thanks for the info on the structural engineer. I had one inspect my house 5 years ago and just reached out to see if hes still in the business.

 

[ddurrett896]

The attachment you provided doesn't account for wind loading?

Virginia Beach.. shouldn't there be hurricane loading there?

I'd suggest contacting a structural engineer.

Good luck with your project.

John

Good catch! They are working up another plan to see if I can triple 16" or 14" and I'll definitely ask. They do have the snow load calculated and while we do get snow, it's not much and they might have just used that column for the calculation. Not sure, just guessing. Thanks!

 

[yeldogt]

Don't need stamped plans for the entire project. A generic wall brace plan and a stamp for the trusses gets passed. The variable I've never dealt with is the large span.

Thanks for the info on the structural engineer. I had one inspect my house 5 years ago and just reached out to see if hes still in the business.

Nobody likes spending money .. BUT, It's been my experience doing many projects over 30 years that getting specialists involved pays dividends. Often they look over a project and find better ways to do a couple things that you had not even factored ... save you money and a lot of grief. Any sag or movement and you will not be a happy camper.

Over the years I have met a lot of great old guys (Engineers/ Architects) that love doing small projects .. it's always worthwhile.

 

[Samh]

Re: Span ? - 22' open

So this is going beyond my garage door. Because of setbacks, the Garage will be shaped like a capital L.

the smaller part of the L is 12' long by 22' wide. I want to pull a car in part the 12' mark without a pole in the middle of the garage. In order to achieve this, I have to span that full 21".

Having a little trouble visualizing. Do you happen to have a sketch?

 

[ddurrett896]

Re: Span ? - 22' open

Having a little trouble visualizing. Do you happen to have a sketch?

Check out the attached. Appreciate the help!

View media item 92198

 

[Samh]

Re: Span ? - 22' open

Check out the attached. Appreciate the help!

View media item 92198

It's too bad you can't run the trusses the 22ft length, Then it seems like you'd only need to worry about the LVL over the door, which at that point wouldn't have too much load on it.

 

[Samh]

From an LVL load perspective, the literature I have, shows a doubled 24" LVL on a 22' span having a load max of 1123Lbs. Three 16" LVLs show 975lbs. So depending on safety factor of the two 24" LVLs, might be doable. But four 16" LVLs show a max load of 1299lbs, which should suffice

****Disclaimer, Not a structural engineer, and know just enough to be dangerous.

 

[GMCGarage]

Re: Span ? - 22' open

The attachment you provided doesn't account for wind loading?

Virginia Beach.. shouldn't there be hurricane loading there?

I'd suggest contacting a structural engineer.

Good luck with your project.

John

Good catch! They are working up another plan to see if I can triple 16" or 14" and I'll definitely ask. They do have the snow load calculated and while we do get snow, it's not much and they might have just used that column for the calculation. Not sure, just guessing. Thanks!

It's too bad you can't run the trusses the 22ft length, Then it seems like you'd only need to worry about the LVL over the door, which at that point wouldn't have too much load on it.

Most garage doors are fastened to the side of the garage door, so your studs at the side take most of the wind load, agree though, that should be some nominal load, which might not matter since its essentially fully braced.

 

[ddurrett896]

Re: Span ? - 22' open

It's too bad you can't run the trusses the 22ft length, Then it seems like you'd only need to worry about the LVL over the door, which at that point wouldn't have too much load on it.

Thought about that, but then the 21’ LVL in question needs to be 26’. Kinda want the back area wide open.

Still an option, but figured the best bet is the shorter. Walls are 10’ and I’m doing a 8’ garage door so the 2’ LVL drop wont impeded me getting anything inside. The only watch is if I added a lift down the road but I can put that in the back where it’s 26’ long and 28’ wide - plenty for a vehicle.

 

[ddurrett896]

Anyone have spam table on a structural steel ibeam? My local lumber yards spec and stamp LVL ratings but all steel places only sell - nobody on site to spec. Thanks!

 

[Samh]

Anyone have spam table on a structural steel ibeam? My local lumber yards spec and stamp LVL ratings but all steel places only sell - nobody on site to spec. Thanks!

See if this helps.

https://cfsei.memberclicks.net/assets/docs/designguides/3_loadspan.pdf

 

[ddurrett896]

See if this helps.

https://cfsei.memberclicks.net/assets/docs/designguides/3_loadspan.pdf

Thanks for the link. To be frank, when I read span tables my head spins

 

[mike93lx]

Thanks for the link. To be frank, when I read span tables my head spins

Another reason to hire a pro

 

[FlyFisher1]

Find a local structural engineer that does residential design. Pay for a couple hours consulting and get your solution. You can sleep better this way.


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