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I guess I just have to cheat

Started by Qweaver, February 09, 2006, 09:41:34 AM

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Qweaver

I've decided that I just don't have time to make all of the joints in the traditional way :'(   So I'm designing metal fabrications that I can quickly build, galvanize and have ready to go for next summer.  I'll keep them hidden in most cases and combine them with conventional joints where possible.  I'll also glue where appropriate.  I wish that I had an experienced timber framer close-by to preview my drawings.  I'll post some pics but the small pics that I can post here don't show the detail very well. Suggestion welcome and appreciated.
Quinton

   
   
   
   
   
So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

TexasTimbers

Q,

I don't see how that drawing detail can be a collar tie. It looks more like a tie beam or girt running into a post, sitting on top of a cleat (don't know the proper terminology). For me, I want any horizontal member like a tie beam or girt catching part of the post, no matter how beefy a cleat might be.

I considered making my own brackets at first but discovered something better for my time/money ratio .... I guess you are familiar with Timberlinx?

Is that Dietrich's you use for the drawings?

How are you going to enclose the structure?

Heck I am asking more questions than you and you asked for suggestions :D

Anyway, my only suggestion so far is to get that tie beam/girt on top of that post.
The oil is all in Texas, but the dipsticks are in D.C.

srjones

Nothing cheating about it.  It's just the way you're doing it and that's the beauty of doing it yourself...you get to decide :)
Everyone has hobbies...I hope to live in mine someday.

TexasTimbers

Something I might add is that of course the girts/tie beams don't have to sit literally on top of the posts, you can haunch them into a housing into the side of the posts but its the same principal: part of the horizontal members are sitting on a part of the post albiet not the tippy top.
This is what I am doing with the Timberlinx. Housing them into the side and not having to cut mortice and tenon.
The oil is all in Texas, but the dipsticks are in D.C.

Qweaver

Kevin,
Of course it is a tie beam, I just wasn't thinking when I labeled it.  Thanks for the timberlinx link.  How costly are they?   I use an older program called Designer to make my drawings.  BTW, I draw in layers and the corner braces don't show on the layer that I used in my posting, but I have them in the plan.
Thanks for the input.
Quinton
So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

srjones

Just wondering...why galvanizing rather than powder coating or anodizing?
Everyone has hobbies...I hope to live in mine someday.

Jim_Rogers

Q:
You may need to have your frame design checked, by either a timber frame structural engineer or another timber framer, some of your design decisions aren't the best:



1 1/2" pins could be larger than what's needed.....
Hard to tell without knowing all the sizes......

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

Qweaver

Jim,
I'm seeking ideas, so I did not include how I intended to complete this joint.  Since the house is only 24' wide, I probably could make a scarf joint in the center and eliminate the joints above the post.  Here's my complete drawing of the joint.  I do have the luxury of having three good friends that are highly experienced engineers and they are closely scrutinizing my design...too closely sometimes.  They are not experienced in timber framing, I might add.  One even suggested (in jest) doing a finite stress analysis, which I think would be a waste of time considering the inconsistency of wood.  I will be using steel on most of the joints, hidden where I can.

SR  Galvanizing is "forever" and I like the look.
Quinton

   
So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

Jim_Rogers

Have one of your engineer friends explain this graph to you:



This would be better:



But it may require a brace for added strength.

Jim Rogers

Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

srjones

Q,

That's what I was guessing :)  I like the look too, but my wife doesn't.  Have you seen it where they use corrugated galvanized roofing sheets for wainscotting?  (in bathrooms and kitchens)  Galvanized pipe makes good handrails also.
Everyone has hobbies...I hope to live in mine someday.

Qweaver

Jim,
I've emailed your shear/moment diagram to my friends in Texas.  I do understand these concepts and I am a little confused as to why there is a a variance in these values from post to post...but Ill wait until Fred looks at them to comment. 
I have redrawn how I'm thinking of doing the rafters.  I was never happy with using a triangular filler but I'm fairly satisfied with this rendition.
Quinton

      


So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

Jim_Rogers

The reason for setting the scarf joint off the post is that is will receive less stress there.

Look at this drawing:



Between the posts the unsupported timber will sag or deflect. Over the center post the timber will crown.
This causes this "exaggerated" wave shape effect in the timber.
At the point where the sag or deflection changes to a crown is called the point of "inflection".
This point is where the timber is neither sagging nor crowning. It has the least amount of both forces.
This, I am told, is where the joint should be made. If I understand all this correctly.

I hope this helps to explain why joints shouldn't be made over posts.

Jim Rogers

(Below is a pdf file of a larger sized scarf timber wave shape drawing.)
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

submarinesailor

Jim,

This is the best explanation of the wave I have heard/seen.

GOOD JOB!!!

Bruce

srjones

Hi Jim,

While we're on the subject, can you take a look at this?



It's already designed and cut, but I'm interested on your take on the potential weakness of this scarf (if any) and how you'd do it differently. 

Thanks,

-Steve

Everyone has hobbies...I hope to live in mine someday.

Jim_Rogers

See drawing in reply #8 for how scarfs should be placed.

Now that it's cut you'll have to live with it.....

On potential weaknesses it depends on what that timber (the one with the scarf in it) is suppose to be doing.
Is it a plate just catching the rafter ends?
Or is it a tie beam in a bent?

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

srjones

It's a mid-span plate holding up the rafters.  From post to post on the long side it's about 20 feet.
Everyone has hobbies...I hope to live in mine someday.


Qweaver

Here are my latest drawing of the front of the cabin.

The cabin will set on 8' concrete block piles, steel re-inforced and concrete filled.   The back wall will be blocks all the way across and the side walls will be blocks 2/3 of the way with the front and 1st 1/3rd open as is shown in the drawing.

Jim, after extensive conversations with my engineer buds, here is what they say.  While the "wave" moments you describe exist, the moments are very, very small and with the way that I am fastening my joints, they say I would be making a mistake to move the laps to an unsupported section, unless I make at least a 6 to 1 scarf and then bond it together with epoxy or similar.  I'm putting garage doors at the front and the 1st section of the side walls, which makes diagonal bracing impossible.   They do think that I must steel reinforce the front sills, which I will do.   Keep in mind that all of my joints will have a 1.5" oak pin bonded in and 1/8" steel plates on two sides.


           

 

So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

Jim_Rogers

Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

Jim_Rogers

Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

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