Vaulted Hip Roof
Vaulted Hip Roof
(OP)
Got an 18x18 ft. carport with a pyramid, vaulted hip roof. I am showing a dogleg W8x24 beam to support the 1 3/4” LVL hips. Trying to create a clean detail for attaching the hips to the beam. I am thinking welding a 1/4” backing plate to the beam flanges and then plug welding a Simpson HRC1.81 to the plate. Anyone got any better ideas?
Thanks!
Thanks!






RE: Vaulted Hip Roof
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Vaulted Hip Roof
I though about the knife plates, but worry about them getting the angles correct.
RE: Vaulted Hip Roof
RE: Vaulted Hip Roof
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Vaulted Hip Roof
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Vaulted Hip Roof
If your kinked steel beam is carrying any load, it loads the top tie beams at mid span vertically and laterally. Maybe not so easy to deal with. You have the tie (tension) beams atop the columns all around. Why not put a bearing shoe over each column and in line with each hip (hip ridge line)? Then the four LVL have a horiz. bearing seat cut (gravity load) , and a vert. plumb cut (for thrust) and the lower end of the LVL just sits down into that shoe, with a couple bolts. Then some fairly simple steel cross up at the top ties the four sets of LVL’s together.
RE: Vaulted Hip Roof
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Vaulted Hip Roof
As far as the kinked beam goes, why is it loading the tie beams laterally?
RE: Vaulted Hip Roof
That being said I have done pretty much the same design dhengr described before and I think it's more than adequate provided the spans are not too long, which in this case you are probably right at that threshold. You would just need to make sure to size the lvls and connections for gravity and thrust.
RE: Vaulted Hip Roof
RE: Vaulted Hip Roof
RE: Vaulted Hip Roof
So, backing it up a bit, did the glulam guys suggest a base detail that you can share with us? Or communicate the process that would be involved?
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Vaulted Hip Roof
Just got off the phone with the Arch. He ain't budging on that as it works best with his uplighting. I may go back to the kinked beam.
The glulam folks said they could either provide a moment resisting base or I could bury the post in concrete. I did go too deep into the base with them as the use of glulams was still up in the air.
RE: Vaulted Hip Roof
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Vaulted Hip Roof
RE: Vaulted Hip Roof
Still I worry that the pyramid/tension ring path will be the stiffest and you'll end up drawing lots of load to the ridge tail connections no matter what you do with the cranked steel beam.
What if you left the ring beams where they are but then cantilevered the columns up past them a bit to improve the rafter connections? On some beefy, moment frame steel columns, that shouldn't hurt anything with respect to the columns.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Vaulted Hip Roof
BA
RE: Vaulted Hip Roof
RE: Vaulted Hip Roof
Yeah, I feel compelled to revisit the issue of my previous firing at this juncture.
If it were my baby, I'd just weld three vertical plates to the column cap plate. You know, so long as they were reasonably sized plates. 1"-1.5" minimum.
If you want to go bargain basement on this -- and I know that you do -- I suppose that you could weld a face mount Simpson hanger horizontal to the cap plate and call it good. You might need to supplement uplift capacity but that's easy enough.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Vaulted Hip Roof
I honestly don't worry too much about uplift on these hips. For short term loading, the roof diaphragm will tend to distribute the load to all the rafters so I have alot of little connections helping.
RE: Vaulted Hip Roof
How are you planning on fastening the 2x10 roof joists to the double 2x8 hips? I usually spec hip beams/boards at least 2" deeper than the rafters/joists. I'm curious how you would do this for fastening? Top mount hangers?
RE: Vaulted Hip Roof
The rafters are spanning 9 ft. max. so just toenails. This is a pretty common connection in our area even for 18 ft. span rafters and I have yet to witness an issue with it.
RE: Vaulted Hip Roof
What purpose is served by the kinked steel beam?
BA
RE: Vaulted Hip Roof
BA,
It was to support the hip rafters before the idea was thrown out by dhengr to rely on resisting the hip thrust by the tie beams.
RE: Vaulted Hip Roof
Okay, thanks. I should have read it more carefully.
BA