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tie beam

Started by bic, January 12, 2013, 08:51:58 AM

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bic

I'm in the early planning a building 24'x28'. Wondering what the best method of joining the tie beam utilizing a middle post, or is it nessasary to have a one piece tie beam, I understand it would obviously be better with one full beam, but I am building in a area that machinery can not access to lift a full bent. could anyone point me to a topic that may assist me with this. I will be using a piece on piece type method.

thanks ahead
bic
LT 28 Woodmizer
where there's a mill there's a way

jander3

With a little thinking, a little rope, a solid place to tie off guy lines, and a couple of snatch blocks, you would be surprised at what you can lift without machinery. 

Rigging with 4 x 4 16' poles from Mendards:
http://peelinglogs.blogspot.com/2011/10/timber-framerigging-raising-frame.html

Rigging with 2 small 25' Spruce poles:
https://forestryforum.com/board/index.php/topic,33283.msg566739.html#msg566739

A lot of great information on rigging:
(clicking on the below link will download a pdf file)
http://www.petrospec-technologies.com/Herkommer/knots/FM5-125.pdf

My brother is welding up some parts, in the spring we will be installing a derrick type crane to build a timber frame structure about the same size as your frame.   We are 3 miles back into the woods by ATV (via Goat Path) so there is no way a crane can get to the site.
http://peelinglogs.blogspot.com/2012/05/it-has-been-some-months-since-i-have.html

Portable Gin Pole set up.
http://peelinglogs.blogspot.com/2009/04/gin-pole-set-up.html

For joining a tie beam in a post that extends up to the ridge, you could use tenon, mortise with shoulder, and then install a spline. 

Jim_Rogers

If you want to join a long tie beam in the middle of a wide frame there are different options.

One has been mentioned that is put the tie beam into a housing for support by the center post, and then connect both sides through the post with a spline. The spline piece is usually made out of hard wood.

Here is an example from a frame in VT that I watched being raised:



Another option is to make two tenons. I call this an over and under joint:



Both of these styles of joining two halves of one tie beam system would/should have some post above the top of the tie beam.

If you're floor system above the tie beam won't allow a taller post then we'll have to come up with another solution.

Here is a picture of one way I did it for a client building a two car garage with no loft above:



You can see the center post and how it is taller then the top of the tie beams. This is to provide enough timber up there so the through mortise doesn't split up the end of the post.

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

Jay C. White Cloud

Hello Bic,

Jon is more than correct, I teach rigging and climbing both, (soon to be re-certified by OSEA.)  You can lift anything from a tank to timber frame with good rigging.  If you go out on the "web," you will find tons of info.  Jon's links can give you some great ideas and info too.  There are books, classes, and all kinds of training.  I'll be teaching in Ohio sometime in the late summer, early fall of this year. 

You can, if you have access to scaffolding, build a scaffold tower, and lift off of that as well.  As much as I like Gin Poles and Shear Legs, that is what I use most of the time on the job.  They just are more transportable and allow you to do other rigging and work off of.

WARNING, as a master rigger/climber, I would be remiss it I did not tell you that proper knowledge/training in the high angle environment of climbing and rigging is dangerous and potentially lethal.  Please be very careful.  The following are just some of the basic safety considerations:

Make a safety check list and have pre and post safety meetings with all present.

Verbalize any actions before you take them.

Make escapable/redundant rigging systems whenever possible.

Always have an escape route planned for any action taken.

As for your frame design, a truss system with a "broken tie beam" is a tricky thing to engineer unless you have lots of timber framing experience.  Check your load math and timber quality.  If you can, have your work "back checked," by others, preferably an architect or P.E. with experience in timber frames.  If they don't know timber framing they are more of a burden than help.  Post your concepts here on the FF and you will get "gobs," of great feedback.  Remember, the better the planning, the easier the work.  Good Luck.

Regards, jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

fuzzybear

JIM, do you have any technical drawings of the spline joint? Are there any rules as to the length and sizing of the spline? Again you have presented me with the solution to a problem that has been bothering me for a while. Thank you!!!
FB
I never met a tree I didn't like!!

Jim_Rogers

Quote from: fuzzybear on January 13, 2013, 12:08:02 AM
JIM, do you have any technical drawings of the spline joint? Are there any rules as to the length and sizing of the spline? Again you have presented me with the solution to a problem that has been bothering me for a while. Thank you!!!
FB

FB: It is my opinion that each spline is unique as it is different in every frame due to loads and frame sizes. And because of that each one should be reviewed by an engineer and evaluated properly.

But, I did create a "general" rule of thumb for spline connections.

Here:



Also, according to one of my engineer's the spline is never pegged to the post. It is only pegged to the beams on either side. And in these cases the peg locations and alignment are very important to not overly weaken the beams or the spline piece.

Personally I like the over and under joint more than a spline.

I hope this has helped you.

Jim Rogers

PS. if you need a larger view of this "spline rule of thumb" send me an email via the regular email system and I'll send you out a larger view.
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

fuzzybear

Thank you Jim!!  I am building a round log, timber frame loft that is being installed inside an existing structure.  I was trying to figure out how to fit it in as tightly as possible. I have 1" clearance on each side wall so trying to fit a "traditional" design would be rather dificult to raise. The spline joint should allow me to "slip" in the tie beams and keep my tolerances tighter, allowing me to keep the posts tighter to the walls.  on the outer posts I will use pocket joints but the center post I am going to use the spline.
Thank you again!!!
FB
I never met a tree I didn't like!!

D L Bahler

You should look into continental European traditions of timber framing like French and German methods. These accommodate tight spaces quite well.

A German frame, for example, is designed to be assembled piece-by-piece instead of as pre-assembled bents. This lets you built in direct contact with existing structures if necessary.

Using this method, the walls would be assembled, tie joists set in place, and then finally the roof members set in place, all step-by-step and quite sturdy when done.

bic

Thanks gentlemen for the ideas,and methods I really appreciate it. Jim I knew there had to be a simple answer to my issue and I to like the idea of the over under joint, my posts are 8"x8's and the tie beam will be 8'x10" should be lots of meat I would guess. I'll keep you posted on the development.

Gord
LT 28 Woodmizer
where there's a mill there's a way

Jay C. White Cloud

Hi Bic,

You could also consider a corbel with a scarf joint above it.  Just a thought.

Regards,  jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

drobertson

I have to ask, is there any calculations considering the moi, and the section modulus and the considered materials in the suggestions of construction considered.  I am sure they are, but for me(us) that don't know anything about timber framing, I was wondering if these structures are built with more timber than necessary, to grasp the desired look. Just a thought. No offense intended. Just an ignorant question.  david
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

beenthere

Quotemoi

Modulus of Inertia ?
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Jay C. White Cloud

Hi David,

Sincere questions can't be ignorant, and I often find yours well thought and lucid.  Comparatively, I'm sure you have noticed, that Asian, compared to European traditional timber architecture is lighter framed in timber, even though they tend to have heavy roofs and are subjected to considerable seismic activity.  Not until you get into Asian Temple or, folk architecture do you start to see the heaver timbers, as in Europe.

So, yes, often timber frames that are built under European or Folk modalities have much more robust structures, than are probably necessary.  There has been historical research and structural analyses of many joint connections, but there is much more to do.  Because of the style I work in, I seldom go larger than 150 mm to 180 mm (~6"to 7") for posts.

Now, I wasn't sure if you had applied any of your question to the "corbel" joint, if so please restate, so I can better respond, and thank you for your interest.

Regards,  jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

Brian_Weekley

Quote from: drobertson on January 14, 2013, 10:36:25 PM
I have to ask, is there any calculations considering the moi, and the section modulus and the considered materials in the suggestions of construction considered.  I am sure they are, but for me(us) that don't know anything about timber framing, I was wondering if these structures are built with more timber than necessary, to grasp the desired look. Just a thought. No offense intended. Just an ignorant question.  david

David, timber frames are designed to use the necessary sizes to accommodate the loads and forces anticipated and are not big "just because".  If you check the left side margin of this page, you'll find the "Red Toolbox" icon.  In it, you'll see "Don P's calculator".  With this tool, you can calculate the size of beams and posts needed for given loads and wood type. There are several threads that show examples.  Here's one:

https://forestryforum.com/board/index.php/topic,61021.0.html
e aho laula

drobertson

Well, one of my sons is in aero-space engineering, we were discussing different things while I was roaming the forum and I came on this one.  The question I guess should have been do you guys do the calculations as they pertain to the strength of any given joint, or do you follow charts that have all the info needed.  And I suppose brian answered this, thanks,   david
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

Jay C. White Cloud

I guess another way to think of it is statistical.  Many of our "charts," are averages, and then the math has "factors," in them as well that comply with engineering "safety margins."  Most post that are in timber frames are much larger than they need to be, by a considerable margin. Beams are also larger, in many applications, because they must meet "margins," with code for deflection.  That does not mean if they had been smaller they would be weak, they would just deflect more and/or out side modern "code" parameters for movement.

There is a style of timber framing that was assumed to grow out of Dutch ship wright traditions, call "Tide Water,"  you can still find many of them in Delaware and Maryland.  They are called "Tide Water Capes"  few have any posts thinker than 100 mm x 150 mm, (4" x 6") and beams are never wider than 150 mm, (6") and most are 100 mm (4") and I've never seen one deeper that 250 mm (10").  Like in the "merchant" or "imperial" class of architecture that reached it's zenith in Japan's Edo period.  The frame work is very light.

So in a sense we do "just pick a size" (or "just because,") and go with it, based on cultural normative developments, which is a hole are of building science that seldom makes it down to the general public level publications.  Why does one culture have different "margins," than another?  We are still examining these questions, as researchers and historians.

Regards,  jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

drobertson

Thanks Jay, it all is very interesting, and I am sure hard work.  It's no wonder why it is so popular, you guys are awsome that build this way. Maybe one day I will try my hand at a small project.   david
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

routestep

I lifted up some pretty big bents. Got to the point where I decided to use chain falls instead of blocks and ropes.

Jay C. White Cloud

I agree with Routestep, if it's really heavy, (what every it is,) and I can keep the direction of pull in line to gravity on the lifting rig (use directionals if needed,) chain falls make for a better/safer systems.  You can have a good backup to on the lifted object and the chain fall makes for smooth lifting/lowering.

Regards,  jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

Mad Professor

Jim,

On your top picture you have shouldered mortice and tenons which decrease the post, then a 2nd tenon on the same area.

Why not have the other tenon above or below to maintain the integrity of the post?

Seems a weak design unless the post is already oversize for the build?

Best,

MP

Jim_Rogers

Quote from: Mad Professor on January 16, 2013, 12:46:18 PM
Jim,

On your top picture you have shouldered mortice and tenons which decrease the post, then a 2nd tenon on the same area.

Why not have the other tenon above or below to maintain the integrity of the post?

Seems a weak design unless the post is already oversize for the build?

Best,

MP

MP:
I assume you're talking about my "over and under" tenon joint where they both meet the post in the middle of a frame. (If not then please let me know which picture you're referring to).
This one:



The post is reduced by 1/2" from actual size to accommodate the "general frame rule" that each joint area has to be reduced by 1/2" from the actual size. This is done on both sides so that the shoulder to shoulder dimension on the tie beams basically match. It also gives the tie beam a housing to sit on to help hold it up.

On one side of the center post I have a over tenon, and on the other side I have an under tenon, so that there is enough relish of tenon beyond the peg hole.

I asked one of my many timber framing teachers what he would do when he has a long span that need to have a two piece tie beam. I asked him how would he join them in the middle, with a spline as I have shown above. Or with the over and under tenon arrangement. He said he likes the over and under tenon. I have used both in my drawings.

I hope this has helped you to understand my answer to your question.
If I haven't got the right picture let me know and I'll do my best to answer you again.

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

drobertson

This is a great point, and the reason for me asking such a question as to how things are figured.  It seems to me that the weight of the timber has as much to do with the overall strength of the structure as the joint itself. And then when a joint is made with a definite shear factor along with a tenion, how is this figured in?  Just asking, I am moved by timber frame construction, I just have to ask is the mass completely necessary, or is it a matter of motif and style?  I am not trying to be argumentative, I just have a young man, that is weight concience as to strength and cost.  david
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

beenthere

Quotesons is in aero-space engineering
Right Dave, you wouldn't use the technique in an airplane.   ;D

I've a son in Aerospace too, and he skips right on by wood (except in his shop).
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

drobertson

This is a tough one.  Dealing with young ones smarter than me, although I am real glad they are ;D  But I have always been one to listen to reason, when reason makes sense.  I have always loved walking into a timber frame constucted structure.  But dealing with a young man who can do a rubiks' cube in around a minute I am at my limits for answers.  I did manage to get the cross in the cube, but then faded to failure.  8)
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

bigshow

Quote from: Jay C. White Cloud on January 12, 2013, 01:20:17 PM

You can, if you have access to scaffolding, build a scaffold tower, and lift off of that as well.  As much as I like Gin Poles and Shear Legs, that is what I use most of the time on the job.  They just are more transportable and allow you to do other rigging and work off of.



Jay, I've been looking for some examples for rigging using scaffolding - I havent found anything useful yet.  Do you have any examples or resources??

thanks.
I never try anything, I just do it.

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