Author Topic: Yet another beam Q for you experts  (Read 3713 times)

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Offline UK4X4

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Yet another beam Q for you experts
« on: July 01, 2011, 04:09:46 PM »

16 ft wide by 24 ft long- ridge at 12ft mark with 16ft span

6x6 posts at 8ft spacings- pole barn BBQ type shack

Ridge beam full load 14400 lbs

Post down to perimeter beam 7200lbs point load at 4ft on an 8ft long span

ie below the ridge beam post and middle between the 6x6 postss

like this ROBOJO photo- only without the central ridge support - mind you I can happily do that to keeps timbers smaller and more managable.

Plus below will be a deck



His span seems to be huge !- when I try and estimate the size it comes out to be lvl type area only not standard timbers.

Q 2 if you added a deck to to the construction pictured would you

A simply hang 2x12's between the posts and then joists across

Or B mount 2x beams to the concrete bigfoots and then bolt posts to them for the roof


Offline Don_P

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Re: Yet another beam Q for you experts
« Reply #1 on: July 02, 2011, 02:51:05 AM »
1) yes, there seems to be a problem here.
Is there a problem with running a post directly under the ridgebeam down to a footing?
Alternatively the roof could be built with lightweight trusses, or heavy timber trusses supporting either a ridgebeam and common rafters or principle rafters and purlins.

2) The deck could be built around the posts, independently supported on each side of the posts down to the footings. The rim could also be let into the posts if they are large enough. There is inadequate bracing in the frame above, each post should have good kneebraces in each direction. The roof is going to be quite a sail.

Offline John Raabe

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Re: Yet another beam Q for you experts
« Reply #2 on: July 02, 2011, 08:19:52 AM »
This looks like the start of a US Forest Service shelter where they use timber braces and timber trusses. Such a structure needs to have an engineer to design the hold downs, connections and bracing for wind, snow and uplift. These are determined by the local conditions.

Perhaps the existing materials can be worked up into a king post truss to carry the roof on purlins spanning over the trusses. But this should not be done with back of the envelope calculations by amateurs such as us. :D :D :D
None of us are as smart as all of us.

Offline UK4X4

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Re: Yet another beam Q for you experts
« Reply #3 on: July 02, 2011, 09:03:08 AM »
The photo is not my construction ............thats Robojo's sun shade some where in Utah !

There's more snow where I'm building hence the horrible loads

I'm still at graph paper and calculations stage !

House is done - almost the engineer did all the beams etc - I'm finishing the dwgs

The problem is he took 2 months and did not supply what we agreed to so main build will be postponed to 2012 now

So this BBQ shack will be behind the main house - access would be impossible after the house so its something I can build this year and the house next.

I'll redue at 6ft centers for the posts and add a center support and see where I am.




Offline duncanshannon

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Re: Yet another beam Q for you experts
« Reply #4 on: July 02, 2011, 10:29:50 AM »
"So this BBQ shack will be behind the main house"

tell us some more about what your plans are for this... sounds intriguing!  BBQ as in a place for your grill or BBQ as in smoker?

I have an electric (Bradley) smoker which is find for now. I dream of getting a big smoker on a trailer that needs to be pulled some day when i grow up!

Having a smoker at the cabin seems like a natural fit!

Home: Minneapolis, MN area.  Land: (no cabin yet) Spooner, WI area.  Plan: 20x34 1 1/2 Story. Experience Level: n00b. 
Build Thread: http://countryplans.com/smf/index.php?topic=10784.0

Offline Don_P

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Re: Yet another beam Q for you experts
« Reply #5 on: July 02, 2011, 05:50:57 PM »
For myself, and in my state at least, these are the buildings you are allowed to do the design work yourself on. This is an accessory structure and is not the refuge you will seek if things get rough. I do design them to code standards but do not have to retain an engineer for an accessory building. These are lower importance buildings than one you would live and sleep in, my outbuildings are my proving grounds. Do bear in mind you don't want this slamming into your primary structure in a high wind... and there is nothing at all wrong with retaining an engineer.

For this structure, if you want that look, I agree with John that I'd use heavy timber kingpost trusses with purlins over a well braced set of posts. The trick with trusses is to first resolve the heeljoint forces, if you can make them check you more than likely have a workable design.

I was checking shear in the heeljoint on my shop trusses here;


This is an early concept sketch for our round tuit backyard patio, the braces are not drawn in although the stonework and roof diapragm provide the real lateral bracing here;


And the first truss, sorry about the screwed up datestamp, the only working camera I had that day was an old game camera that was on it's own time;

Offline duncanshannon

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Re: Yet another beam Q for you experts
« Reply #6 on: July 02, 2011, 06:05:30 PM »
Don- love the patio design! Gonna bookmark that for future reference for sure!

Are those 6x6 beams?
Home: Minneapolis, MN area.  Land: (no cabin yet) Spooner, WI area.  Plan: 20x34 1 1/2 Story. Experience Level: n00b. 
Build Thread: http://countryplans.com/smf/index.php?topic=10784.0

Offline Don_P

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Re: Yet another beam Q for you experts
« Reply #7 on: July 03, 2011, 02:32:21 AM »
That is mostly 8x8's, the bottom chord is 8x10. It's easier to get the joinery into a larger timber without unduly weakening it... plus big wood looks cool  ;D

Offline UK4X4

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Re: Yet another beam Q for you experts
« Reply #8 on: July 03, 2011, 05:49:34 AM »
Yep - thats the sort of thing !

love those trusses !


 

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