16' opening Door header: on load bearing wall

[rtimgray]

I think you're right.

 

[radioman]

my bad -- according to this chart http://www.southernpine.com/media/SS_1-6L.pdf , table 1-30 you can use 3 2X12's grade 1 you can span 16ft with snow load of 30 . is this what you were looking for? I know its going to stick out half inch, but what can you do with your budget?

 

[GPintheMitten]

Full disclosure: I am not an engineer and didn't even sleep at a Holiday Inn Express.

FWIW, I had my doubts about your load calculations, but I did the simple math and I agree with your point load calculation.

If you go with your own laminated beams similar to your last design sketch, the middle section with two 2x6's and one 2x8 is 1/4 inch less than 2 stacked 2 x 10's.

How are you connecting your beam to the posts? Are you placing the beam on top of the 6x6's? I hope so.

I would caution you to design a robust fastening technique for the beam to post connection. Possibly here is a good place to use some steel plate in a triangle as a gusset on the face of the beam and post on the inside, lagging it to the beam and post. Possibly 1/4".

For that matter, you could place gussets on the outside as well. I doubt that it would interfere much with the steel siding.

 

[LD1]

my bad -- according to this chart http://www.southernpine.com/media/SS_1-6L.pdf , table 1-30 you can use 3 2X12's grade 1 you can span 16ft with snow load of 30 . is this what you were looking for? I know its going to stick out half inch, but what can you do with your budget?

I think you misread the chart.

The 3 2x12's is only good for spanning a 16' width building AND with a uniformly distributed load.

Look under 16' span at the FAR RIGHT fora 40' roof span and it calls out a 3-1/2x14 LVL......BUT once again, that us for a uniform load only. IE: 2' OC trusses or less.

The truss doesnt distribute any weight.

ALL the weight of the truss (which is clear spanning the 40' building) is gonna be resting on where the truss sits on top of the wall. In my case, that is right in the middle of a 16' door opening.

So.......An 8' OC truss with a total load of 30PSF spanning 42' (8x42x30=10,080lbs). So there is 5040# resting on where the truss meets wall or header. Add 1000# safety factor and I need to design for 6000# point load smack dab in the middle of the header......

 

[LD1]

Full disclosure: I am not an engineer and didn't even sleep at a Holiday Inn Express.

FWIW, I had my doubts about your load calculations, but I did the simple math and I agree with your point load calculation.

If you go with your own laminated beams similar to your last design sketch, the middle section with two 2x6's and one 2x8 is 1/4 inch less than 2 stacked 2 x 10's.

How are you connecting your beam to the posts? Are you placing the beam on top of the 6x6's? I hope so.

I would caution you to design a robust fastening technique for the beam to post connection. Possibly here is a good place to use some steel plate in a triangle as a gusset on the face of the beam and post on the inside, lagging it to the beam and post. Possibly 1/4".

For that matter, you could place gussets on the outside as well. I doubt that it would interfere much with the steel siding.

Yes, the middle section will be 1/4" shorter. Was just gonna space the 2x6's out 1/8" away from the 2x8 so the beam is flush all the way around.

as for the attaching method, thats a bit more complicated...

HArd to draw it in 3D so I'll try to describe.

Basically I am gonna notch the top of the post 1.5" in on 2 sides. The outside notch will carry the outer ply of 2x10's. Then there will be a notch perpendicular to that for the truss to set on. Basically leaving a 4x4 post at the top for securing the truss to.

The two plys of the beam I left out will rest on a 2x6 "scab" attached to the side of the post and running down to ground or near it.
I'll see if I can draw something up

 

[LD1]

See if you can make sense of this mess:laughing:



The header and truss will both be bolted with multiple bolts of appropriate size

 

[GPintheMitten]

See if you can make sense of this mess:laughing:

View attachment 395056

The header and truss will both be bolted with multiple bolts of appropriate size

I made sense of it. I understand why you want to leave 4 X 4 of the post above the beam to fasten the truss to but I think the fastening of the beam to the post might be inadequate. I would want the beam to be fully supported by the post.

I think you would be better off placing the truss on top of the ends of the beam like it will be in the midpoint. Then either use hurricane connectors to secure the 3 trusses to the beam. Or you can bolt a 24 inch 4 X 4 to the beam for each of the 3 trusses and bolt each truss to that.

I would be concerned with supporting 2/3 rd of the beam with a scabbed 2x6.

 

[JimRB]

9,000 pounds of load on a scab? One truss in the middle half load and one truss on one end or the other. Yes the doodle shows one 2x of three supported by the post but the other 2 supported by a scab. Are you going to use 16' 2x8 SYP purlins standing up to help carry that load off the center truss?

How often do you have 40 pound snow load on a roof for a long time? A metal roof with a 6/12 pitch is going to shed that snow on a sunny day isn't it? It has been 30 years since I lived up north. Down here snow is off a 4/12 shingle roof in 3-4 days. That said every so often we have roofs collapsing from snow or water load.

 

[LD1]

Not sure where 9000LBS came from.

The trusses will sit in a notch on the post (as per the drawing). The scab only has to carry half the load of the middle truss...3000lbs.

And I wasnt talking a 12" or 18: scab either. That scab would go all the way to the ground.

 

[GPintheMitten]

I recommend bolting or lagging rather than nailing the scab to the post if you are going to go with a scab to support the beam ends.

I still recommend placing the whole beam on top of the post but it's your barn... and it might be totally fine your way