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Truss Designer 2015 Updates

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Truss Designer 2015 Updates
[#52] Posted: 12/22/2015 - 05:38:13 AM
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Quote: Originally posted by medeek

Note, the birdsmouth cut at the lower bearing point. What I am not showing is the additional web blocking (stiffeners) required at this bearing point and at the ridge beam, see [url=http://www.woodbywy.com/document/tj-4000/]TJI-4000[/url] for more details.


Looks to me that the inked document doesn't allow a birdsmouth at any location other than the end of the joist. And when you do that, it isn't a true birdsmouth.

Marc

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[#53] Posted: 12/23/2015 - 2:59:09 PM
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Version 1.2.2 - 12.23.2015
- Structural outlookers notched around TJI top flange when oriented vertically, as per TJI manufacturer's structural details.



The tails of the TJI joists at the overhangs is left untrimmed however it is very easy to trim the tail of the rafters as shown below to customize to your particular roof requirements.


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[#54] Posted: 12/23/2015 - 3:00:43 PM
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Quote: Originally posted by Marc

Looks to me that the inked document doesn't allow a birdsmouth at any location other than the end of the joist. And when you do that, it isn't a true birdsmouth.

Marc


They only allow a birdsmouth cut at the lower end bearing location. At the ridge you must use either a hanger or a bevelled plate, no birdsmouth or notching allowed.

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[#55] Posted: 12/29/2015 - 06:27:53 AM
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Version 1.2.3 - 12.29.2015
- Added Hip Rafter Roof.



A square hip roof (pyramid):



I still need to add in the advanced options for this roof type (sheathing, fascia etc...) I'm also thinking about ceiling joists and how best to configure them. For low pitch hip roofs the ceiling joists near the hip ends will clash with the hip jack rafters unless they are oriented parallel to the jack rafters.

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[#56] Posted: 12/29/2015 - 8:16:56 PM
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A more complex hip roof combined with some trusses. Note I have not trimmed back all of the rafters in the top image.



I initially generated the hip roofs (two rectangles) and then deleted the appropriate members and trimmed the common rafters to create the valley jack rafters and cripple jack rafters. The valley rafter was created by copying an instance of one of the hip rafters and moving it into place. The end result is:



Overall the process has been simplified by having the hip roof feature in the plugin. Trimming the members is the most time consuming, perhaps a more efficient trim tool can be devised so that intersecting members can be easily trimmed back to clean up a complex roof. Ultimately it would be cool to have the plugin automatically handle even more complex roofs such as this but that would take some serious programming.

Also note that I used a raised heel for the trusses so that the heel height and gutter line of the trusses matches that of the rafters.

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[#57] Posted: 12/30/2015 - 05:32:31 AM
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Quote: Originally posted by medeek


I initially generated the hip roofs (two rectangles) and then deleted the appropriate members and trimmed the common rafters to create the valley jack rafters and cripple jack rafters. The valley rafter was created by copying an instance of one of the hip rafters and moving it into place. The end result is:



Truncating that hip and replacing the jacks at that intersection of valley, ridge and hip with commons makes for complications in framing it up. I can't even quite come up with a clear progression for erecting that portion of the roof. It becomes very straightforward if you leave that hip intact all the way to the eaves.

If I was lead framer and I saw that on the blueprints, I'd do it my way instead and avoid that complication. There's nothing structurally wrong with doing so.

Marc

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[#58] Posted: 12/30/2015 - 6:20:10 PM
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Quote: Originally posted by Marc
Truncating that hip and replacing the jacks at that intersection of valley, ridge and hip with commons makes for complications in framing it up. I can't even quite come up with a clear progression for erecting that portion of the roof. It becomes very straightforward if you leave that hip intact all the way to the eaves.

If I was lead framer and I saw that on the blueprints, I'd do it my way instead and avoid that complication. There's nothing structurally wrong with doing so.

Marc


That is what I had originally when I first intersected the two rectangular hip roofs. To be perfectly honest I'm not an expert on complex hip roofs framed the old school method. Locally I mostly see roofs framed out with trusses. I will need to spend some time researching traditional roof framing.

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[#59] Posted: 12/30/2015 - 8:32:51 PM
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It's more about procedure then framing method.

I've figured out a procedure that might work: On the larger system, install the ridge, 6 commons (2 on each side of ridge and last 2 will butt into each end of ridge) and 3 hips. Leave your truncated hip off for now. That much could stand alone without falling. Next step is to install the smaller system that lies at a right angle to the first one - this time just the ridge, 5 commons and 2 hips. Again, that will stand alone just fine with braces. Third step is to install your truncated hip from ridge of first system to common rafter on second system. Everything remaining is straightforward.

Never done it, never seen anyone do it but it should work.

Marc

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[#60] Posted: 01/08/2016 - 03:06:57 AM
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Version 1.2.4 - 01.08.2016
- Plugin integrated with the [url=http://design.medeek.com/calcu...lator.pl]Medeek Truss Designer[/url].
- Engineering of common fink truss enabled.



When a new truss is created (common truss types only for now) the parameters are specified within the dynamic component attribute library. Opening the component options allows one to change some of these values.

The new engineering icon allows one to automatically transfer all of the truss design parameters directly from SketchUp to the Truss Designer for engineering checks.

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[#61] Posted: 01/10/2016 - 02:15:13 AM
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I've done some maintenance on the beam calculator in preparation for integration with the Truss Plugin:

Version 1.0.1 - 01.10.2016
- Updated javascript front end so that selected options are properly retained.
- Updated total load (reactions) to include applied load and selfweight over total span. Results now more closely agree with WoodWorks Sizer Software.
- Inputs now include option for Total Span and Clear Span.
- Removed beam configurations that are not yet complete.
- Beam graphic now shows span geometry with supports.

http://design.medeek.com/resou...lator.pl

At some point I need to come up with a slicker interface that allows for multiple point loads and supports but that is a job for another day.

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[#62] Posted: 01/10/2016 - 5:19:53 PM
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Version 1.2.5 - 01.10.2016
- Plugin integrated with the Medeek Beam Calculator.
- Engineering of North American glulam beam sizes enabled (Western, Southern Pine).

Also note that the Beam Calculator has a very nice PDF report output than can include client and job information.

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[#63] Posted: 01/11/2016 - 7:03:06 PM
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First tutorial video:

https://www.youtube.com/v/1WqGkK15zYA

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[#64] Posted: 01/12/2016 - 2:38:24 PM
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Engineering Video:

https://youtu.be/f0y7y8WtjDw


The SketchUp model used in the video can be found here:

https://3dwarehouse.sketchup.c...746ab90a

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[#65] Posted: 01/12/2016 - 8:11:43 PM
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Valley Truss Set:

https://youtu.be/CrI7pdEfb1o

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[#66] Posted: 01/13/2016 - 01:06:07 AM
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Hip Roof Framing:

https://youtu.be/zyHuGR6nwpg

SketchUp model used in the video can be found here:

https://3dwarehouse.sketchup.c...1d51302d

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[#67] Posted: 01/21/2016 - 10:37:42 PM
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For the next week or so I'm going to spend some of my free time on wood gusset plate engineering. I'm going to post engineering questions and some quasi-engineering questions regarding the connections. Realize that some of these questions are me thinking out loud, contemplating how best to approach this type of truss design.

I'm looking at the nailing of the gussets right now and I'm considering the difference between nails in single shear or double shear. For larger fasteners (ie. 16d nails) it would seem optimal to clinch them on the reverse side and then calculate them in double shear. My question is at what length of fastener exceeding the total thickness can I functionally clinch the nails and consider them in double shear.

For argument sake lets assume a 1.5" truss ply thickness and 1/2" gusset plates each side giving a total thickness of 2.5". An 8D common nail is 2.5", however I would not consider it in double shear in this application. If I were to use a 10D thru 16D common nail in this situation I would have at least 1/2" of nail or more to clinch so in those cases I think I could safely assume clinching was possible and nails are loaded in double shear. Would less than 1/2" of nail protrusion be too small to clinch?

To open up the calculations to as many options as possible I'm considering 8d, 10d, 12d and 16d nails with all the three possible nail types: common, box, sinker.

I also considering 6d and 7d nails but I'm not sure if I will allows those yet.

The plywood or OSB thickness will be: 3/8, 7/16, 15/32, 19/32, 23/32.

Giving this even more thought it would seem that certain gusset thicknesses and nail combinations would not be optimal if the possibility for clinching and double shear is not possible. For instance if I have 23/32" gusset plates on both sides and 1.5" truss ply for a total thickness of 3". If I were to use a common 10D nail or 12D nail I probably could not clinch and therefore double shear is not possible, hence I would have to nail the truss from both front and back. Would this not tend to cause the main member to have more tendency to split since there are double the nails in it. It would also require roughly double the nails.

I'm also going to assume that the osb/ plywood is Structural I, this would be my recommendation anyways in an effort to eliminate defects and require a stronger material for the gusset plates. This affects both the shear values of the gusset plates and the lateral loading capacity of the nails.

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[#68] Posted: 01/22/2016 - 05:03:21 AM
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Quote: Originally posted by medeek

For the next week or so I'm going to spend some of my free time on wood gusset plate engineering. I'm going to post engineering questions and some quasi-engineering questions regarding the connections. Realize that some of these questions are me thinking out loud, contemplating how best to approach this type of truss design.

I'm looking at the nailing of the gussets right now and I'm considering the difference between nails in single shear or double shear. For larger fasteners (ie. 16d nails) it would seem optimal to clinch them on the reverse side and then calculate them in double shear. My question is at what length of fastener exceeding the total thickness can I functionally clinch the nails and consider them in double shear.

For argument sake lets assume a 1.5" truss ply thickness and 1/2" gusset plates each side giving a total thickness of 2.5". An 8D common nail is 2.5", however I would not consider it in double shear in this application. If I were to use a 10D thru 16D common nail in this situation I would have at least 1/2" of nail or more to clinch so in those cases I think I could safely assume clinching was possible and nails are loaded in double shear. Would less than 1/2" of nail protrusion be too small to clinch?

To open up the calculations to as many options as possible I'm considering 8d, 10d, 12d and 16d nails with all the three possible nail types: common, box, sinker.

I also considering 6d and 7d nails but I'm not sure if I will allows those yet.

The plywood or OSB thickness will be: 3/8, 7/16, 15/32, 19/32, 23/32.

Giving this even more thought it would seem that certain gusset thicknesses and nail combinations would not be optimal if the possibility for clinching and double shear is not possible. For instance if I have 23/32" gusset plates on both sides and 1.5" truss ply for a total thickness of 3". If I were to use a common 10D nail or 12D nail I probably could not clinch and therefore double shear is not possible, hence I would have to nail the truss from both front and back. Would this not tend to cause the main member to have more tendency to split since there are double the nails in it. It would also require roughly double the nails.

I'm also going to assume that the osb/ plywood is Structural I, this would be my recommendation anyways in an effort to eliminate defects and require a stronger material for the gusset plates. This affects both the shear values of the gusset plates and the lateral loading capacity of the nails.


This oughta be interesting. Never heard of it being done before, not with osb/plywood.

Marc

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[#69] Posted: 01/22/2016 - 11:16:37 AM
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Are you talking about building a truss on a bench or repairing a truss in situ?
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[#70] Posted: 01/23/2016 - 10:41:33 AM
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I'm sorry but I must address a very important aspect of the truss design software. You need a name for the person in your renderings. I would like to suggest the following : Eddie Engineer, Arti Architect and Betsy Builder.
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[#71] Posted: 01/24/2016 - 9:07:18 PM
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Its hard to say what requires more effort, double the nails or clinching. I've thought about 6d, 7d or even 8d nails in single shear but to avoid splitting the spacing drives the nails apart and the gussets are going to get too large in my opinion. For now I'm going to start with nails only in double shear but may add in a single shear option later.

I've got the front end working now so you can look at the input options. It doesn't do anything yet (actually defaults to metal plates if you choose the wood option), but it gives an idea of the gusset options.

With wood gussets the web-chord joints are going to be much stiffer than with metal plates so I will probably set up the matrix analysis to consider all joints as rigid instead of pinned. I'm actually still thinking about that and talking to other engineers with regards to pinned, semi-rigid or rigid joints with this type of construction.

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[#72] Posted: 01/24/2016 - 9:30:30 PM
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Quote: Originally posted by Marc

This oughta be interesting. Never heard of it being done before, not with osb/plywood.

Marc


This is the way trusses used to be built before the advent of metal plate connectors in the 50's. There are certain situations where it makes sense to still build trusses this way and that is why I am pursuing this.

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[#73] Posted: 01/24/2016 - 11:44:27 PM
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What about staples as an optional fastener? It's much more economical than nails and would likely become favored by contractors.

Marc

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[#74] Posted: 01/26/2016 - 4:25:18 PM
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Version 1.2.7 - 01.26.2016
- Added advanced roof options for hip rafter roof (sheathing, fascia).



[url=https://3dwarehouse.sketchup.c...66e7a252]https://3dwarehouse.sketchup.c...66e7a252[/url]

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[#75] Posted: 01/26/2016 - 4:27:02 PM
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If the gusset plates are to be in single shear it might make more sense to use staples, probably less chance of the splitting the main truss members.
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[#76] Posted: 01/26/2016 - 5:48:53 PM
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Quote: Originally posted by medeek

Its hard to say what requires more effort, double the nails or clinching. I've thought about 6d, 7d or even 8d nails in single shear but to avoid splitting the spacing drives the nails apart and the gussets are going to get too large in my opinion. For now I'm going to start with nails only in double shear but may add in a single shear option later.

I've got the front end working now so you can look at the input options. It doesn't do anything yet (actually defaults to metal plates if you choose the wood option), but it gives an idea of the gusset options.

With wood gussets the web-chord joints are going to be much stiffer than with metal plates so I will probably set up the matrix analysis to consider all joints as rigid instead of pinned. I'm actually still thinking about that and talking to other engineers with regards to pinned, semi-rigid or rigid joints with this type of construction.


I would recommend extra nails because the contractor never gets to the note that requires cinching of the nails.

 
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