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16' Garage Door Headers

It looks like a 3-1/2x12 LVL beam.

Judging by the fact the garage is at a corner, most likely the garage opening is a portal frame. Minimum net header is 3x11-1/4.

In order to determine if the beam is properly sized, one needs the truss reactions for the imposed loads and the span width/bearing dimensions.
 
Duh ... the builder slaps up the cheapest header he can find, and has not bothered to get the loads engineered. The guy at home depot assured him it was the right size.
 
Ok, went back and looked at the picture again. First picture shows a 2x4 wall and the lvl is recessed quite a bit. I wonder if they installed a 1-1/2” lvl but the manufacturer load tables probably called for 3”.
 
e hilton said:
Ok, went back and looked at the picture again. First picture shows a 2x4 wall and the lvl is recessed quite a bit. I wonder if they installed a 1-1/2” lvl but the manufacturer load tables probably called for 3”.
Click to expand...
Uh, that's a 2x6 wall in the picture.
 
Data needed to calculate load on garage door header
Truss profile
any extra loads such as the corner of the second floor over the garage (photo of this area of the garage ceiling would be good)
photo of the full header from the inside
photo of the garage ceiling from the garage door look back into the garage
width of garage
depth of garage
how far forward does the garage jut forward of the house
width of opening =16'
height of header
stud depth
depth of recess at the header from the interior of the flat plates
 
A wider angle view of the door opening from the inside so we can see the entire inside of that wall could be very helpful. The pictures you showed were to close up to get a feel for how the entire wall is constructed.
 
Seeing as how Jeff seems to love when people resurrect this thread......

mtlogcabin said:
GHR

Can you point to a Table in the IRC that allows a 16 ft opening and what size header is to be used? Bearing or non-bearing wall.
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Who is in agreement that beam/header/ girder spans >16' are outside the IRC?....Getting the open floor plan 20'+ center bearing wall removal more and more and thinking about instituting a policy.....This particular one is just attic/ ceiling so like 3000# reactions so not crazy, but do you have a "longer than 16' gets a stamp" policy? Case by case on loading? All LVLs get seals? Other?...Thanks!
 
steveray said:
Who is in agreement that beam/header/ girder spans >16' are outside the IRC?
Click to expand...
FWIW, R301.1.1 permits designs in accordance with the AWC Wood Frame Construction Manual, and that document includes header span tables for glulams, which can get you over 16'. Not sure if that's "outside the IRC," or inside the IRC by reference, but it is prescriptive.

Cheers, Wayne
 
wwhitney said:
FWIW, R301.1.1 permits designs in accordance with the AWC Wood Frame Construction Manual, and that document includes header span tables for glulams, which can get you over 16'. Not sure if that's "outside the IRC," or inside the IRC by reference, but it is prescriptive.

Cheers, Wayne
Click to expand...
But again...that is the SPAN.....What holds it up and how important is that to the total design?...I have had people propose LVL beams with 34,000# reactions and the PT plate fails in compression perpendicular to the grain....Stuff we shouldn't be doing....
 
steveray said:
But again...that is the SPAN.....What holds it up and how important is that to the total design?...I have had people propose LVL beams with 34,000# reactions and the PT plate fails in compression perpendicular to the grain....Stuff we shouldn't be doing....
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My general rule of thumb, and that is all it is, is where the load exceeded 20,000lbs, I would require a post calculation. Post calculation would need to consider the plate crushing, which typically meant that the post would be continuous through the plate (plate gets strapped). (2100lbs/ply for 2x4 wall or 3,300lbs/ply for 2x6 wall).

If using trusses, the truss calculations also will note where plate crushing may be an issue. Same goes for most beam calculations.

For common lumber, I generally watch for anything over 400psi on the bearing. Hem Fir has a compression perpendicular to grain stress limit of 405psi, with douglas fir being 625psi. If needed, I would require a note specifying plates to be DF#2 or better (common in my area anyways).

Getting calculations can be a struggle, but some of the local engineers are quick to help out those in need for a fee. Don't need full engineering design, just review and calculations.
 
steveray said:
WOW....20K?....I start paying special attention at 12K....And explain that 9K is like parking their truck on 16 square inches ish.....
Click to expand...
Not saying I don't pay attention below that, I just don't push for engineer's calculations until I hit 20k. (Note: 20k is the upper limit for a (3)2x6 post 10' tall at Pc100).
 
steveray said:
But again...that is the SPAN.....What holds it up and how important is that to the total design?...
Click to expand...
The WFCM also has tables for the number of jack studs required, so it covers that as well.

For an example from the 2018 WFCM, Table 3.22A1 tells you that for a laterally unsupported (dropped) header in an exterior load bearing wall supporting a roof and ceiling of 20 psf dead, with an allowable deflection of L/240, and a 20 psf live load with a 36' building width (so a header in an eave wall, not a gable wall) a 5.125" x 13.75" glulam can span 17' 10". The footnotes tell you that it assumes #2 DF-L, H-F, SP, or S-P-F, and to see Table 3.22F for the number of jack studs.

Table 3.22F tells you that for the 36' building width, 20psf live load, and 5" deep header, supporting just a roof and ceiling, for an 18' span you need 3 jack studs at each end, so the header would have 4.5" x 5" of bearing at each end. Presumably the cross grain compression capacity of the bottom plate is reflected in that prescription.

Then Table 3.23A tells you that for Exposure Category B, that 5.125" x 13.75" glulam dropped header is fine for the 17'10" gravity span for 3 second wind gusts up to 160 mph, but if the 3 second wind gust is 170 mph, that consideration limits the span to 17' 3".

Cheers, Wayne
 
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