# Truss Calculator



## medeek

I was really hoping to get my hands on a a good truss software even if I had to shell out the big bucks. I contacted Miitek and Alpine and neither of them are willing to sell or lease their software to an architect or engineer. Something about trusses becoming a commodity. Bottom line is there aren't a whole lot of decent truss calculators/designers out there. If you want a truss design you have to get a truss manufacturer to quote you on a job and generate the engineered plans. 

So I purchased a couple of books and starting reading up on trusses and how they are manufactured and designed. I've still got a lot to learn but just today I started into programming a basic truss estimator:

http://design.medeek.com/calculator/calculator.pl










I've already added a few truss types, but the most complete to-date is the Fink truss which I have added all of the member analysis and deflections. I will be adding the plate analysis next and then duplicating this to the other truss types as time allows.

I apologize that Internet Explorer does not currently work with the images, for some reason there is no native SVG support in Microsoft browsers. However, there is a plugin you can install if IE is your browser of choice.


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## griz

I don't understand what you are trying to gain.

I call the Truss Yard and in a few minutes get a price.

If I need the calcs for plan check I just go pick them up.
Not sure what your program would be estimating. There is a great deal of spread in truss prices. Local guy is delivering 6 hours away and making money.


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## medeek

*Truss Design*

And therein lies the problem. 

The designing and engineering of trusses should not be controlled by "plate manufacturers" and "truss plants" it should be controlled by architects and engineers.

The plate manufacturers will only sell/lease their software to truss plants and not to licensed architects and engineers who could actually benefit from their software in the design and planning stages of many residential, commercial and agricultural structures.

I have given this some thought and the goal of this app in its final incarnation is the following:

This application is intended to be used primarily by Design Professionals (architects, engineers, etc.), Building Code Officials, Contractors and Inspectors with the goal of helping everyone that uses it to more easily understand the loads, parameters, calculations and limitations of a given common truss design. By changing geometry and loading parameters multiple design scenarios can be quickly compared and analyzed, hopefully providing a benefit to the design professional. However, let it be noted that this application is purely a tool to be used, similar in concept to that of a calculator or estimator.

In doing so I also hope to force the plate manufacturers to release a version of their software that is for use by architects and engineers. 

I contacted both Alpine and Mitek a few months ago and was hoping to purchase or lease their software as I designed some new detached garages. Their answer to me was that they did not want their truss products becoming a commodity so they would not let anyone access their software except for authorized truss manufacturers who also purchased their plates. 

The design of metal plated connected wood trusses in America is essentially a black box to most practicing engineers and architects. 

I intend to change this.


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## griz

I see from your web site that you are a Mechanical Engineer.
Do you have an in house SE to stamp your designs/plans? Maybe Washington is different.

So, if you were to design a project & used your Truss Design program, does it provide a cut list to the truss yard?

It seems if you take the design away from the Truss Yard you have introduced another player in the game which means another chance for error.

It would be curious to see if a Truss Yard would actually build your design or would they run it through their own program. Who would inspect/certify that the Truss Yard built exactly to your design. I wonder where the Truss Yard liability/guarantee would be using your method.


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## Dirtywhiteboy

Griz I have a friend here that has opened and sold at least 4or 5 truss co. He is now an estimator for a big contractor and has builder ask him for truss design and the truss plant builds them.


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## Kent Whitten

medeek said:


> ... it should be controlled by architects.....



:laughing: oh HELL no! It would be the LAST group of people it should be controlled by. 






medeek said:


> ... and engineers.


I think that they have enough on their plate. 

It's a free (well sort of) market. You want to try changing it, go ahead.


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## Kent Whitten

Dirtywhiteboy said:


> Griz I have a friend here that has opened and sold at least 4or 5 truss co. He is now an estimator for a big contractor and has builder ask him for truss design and the truss plant builds them.


He probably has the truss software, no?


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## Warren

I think that whoever is fabricating the trusses should have control over the engineering. There are enough mistakes that happen with the way things are now. Adding another in the chain of command will just mean more errors. Our truss companies here work with builders and designers really well. They will even accept input from us framers on occasion. Many times I have submitted some crude sketches to see if an area can be trussed or not. I am sure that the engineers and architects do the same thing.


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## hdavis

A calculator would be convenient, but anyone with the background can analyze a truss design, like you're doing. I don't see why any FEM software couldn't be used to do the analysis on a computer - maybe I'm missing something.

I'm not interested in specifying a truss design - it doesn't save me money and it shifts liability on to me.


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## medeek

Wow, a lot more responses to this than I expected. 

I understand that many architects, designers and even engineers don't really care to know what goes on inside the blackbox of truss design, I can respect that. However, there are situations where a tool like this could be useful for a designer and even though that designer may not spec out the truss fully on his plans and probably shouldn't, sometimes it would be nice to do a quick check to see if a certain truss design will fit an application.

For example I recently designed a detached garage with attic trusses. Some of the things that affected my design directly via the truss design were: overhang thickness (2x4 vs. 2x6), bottom chord depth, 3ply vs. 2 ply girder trusses, top chord depth.


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## CarpenterSFO

The plate manufacturer's software isn't "truss engineering software", it's "truss design with our brand of plates" software. For liability and quality and reliability and reputation reasons, I can't imagine a plate manufacturer licensing that software to anyone but a truss maker certified by them, or an engineer like DWB's friend, who has a track record to trust.

As a contractor, I don't want to pay my engineer to design trusses - he has plenty of other work to do, and the truss company does the job just fine, given a set of requirements. Anyway, I don't think my engineer wants to design trusses, and I'm almost certain that every architect I've ever worked with, talked to, or passed on the street, doesn't want anything to do with it.


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## hdavis

Why not use one of these?


http://www.iesweb.com/solutions/truss/truss-design-software-b1.htm?gclid=CPKopdDTk7gCFY2d4AodKh8Axw

http://www.jhu.edu/~virtlab/bridge/truss.htm


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## medeek

I like the app hosted by jhu.edu, its actually quite fun to use. I've used it a number of times as a third party check on my statics calculations, so if definitely has its uses.

However, I'm looking for something that conforms to all the TPI standards and does the required calcs for lumber and deflections.


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## Kanding

I may be missing something, but you’re an engineer and you don’t know truss analysis? Even if you’re not civil, didn’t you cover truss and beam analysis in your statics and mechanics of materials classes? To design the connectors and determine allowable stresses for material grades, look in NDS. To determine design loads, look in ASCE 7. You may want to consider briefly hiring a junior/senior college student in civil who took a wood structures design class to write a truss program for you in Excel. Pretty basic stuff. Good luck.


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## medeek

I'm not talking about statically determinate truss analysis, I need the more in-depth stuff like matrix analysis (which I'm currently studying from my structural analysis book [Hibbeler]) and plate sizing based on the TPI 1 standard. Not something you get in your standard statics or mechanics of materials classes.


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## Kanding

That makes more sense, though I think you’ll find that many common trusses are in fact determinate when you remove all of the zero-force members for analysis. You might also check out an old hand method for complex trusses I think called the 'method of substitute members'. 

However, you’re certainly on the right track with the direct stiffness method (i.e. matrix analysis)—its great because, as you probably found out by now, its easy to program, requires no modification or change in procedure to solve determinate or indeterminate structures, and you really only have to deal with one general element type (frame element) that will handle axial force, moment, torsion, and shear effects. 3D coordinate transformations are somewhat cumbersome, though. This approach is the backbone of all modern structural analysis in structural engineering.

If you later want to go further into more complex stress analysis and move on to the finite element method, you’ll find that it uses the direct stiffness framework as well. I have read quite a few, and I think Hibbler’s coverage (though I’m sure I don't have the most current edition) of direct stiffness is fine. My guess is, however, you can find a number of free direct stiffness codes on the internet if you don't want to do the programming yourself. 

If you have any questions about direct stiffness or FEA, let me know, I deal with these frequently and I'd be happy to help. 

Good luck!


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## medeek

*Matrix Analysis*

After about a good week of solid programming and scratching my head I've finally managed to add the requisite Matrix Analysis to my Truss Calculator. Thank-you R.C. Hibbeler for your Structural Analysis text on the subject (ch. 14 - 16), if the subject had not clearly laid out in front of me I would never have figured out the numerous steps to arrive at the solutions. 

Here is an example of the output of my matrix analyzer for the Fink truss:










I've even inserted the correct code to account for the additional loading/moments if there are overhangs. I double checked my work by modeling up identical trusses (beams and trusses members) in both Strand7 and Solidworks (COSMOS/Simulator). My result were within 1.5% or better, so I'm really happy about that.

My only concern with my analysis is how correct my analog for the truss really is. What I mean is that the bending moments are heavily influenced by the amount of rigidity of the joints. Fixing the joints (where chords meet) or pinning them dramatically affects the bending moments and even the axial and shear loads to some extent. My analog model is basically rigid at the heel and peak joints and pinned at all other web-to-chord or web-to-web joints. This seems to approximate most closely the moments calculated using the simplified method (pre TPI-2002). 

What I also found quite interesting (and expected) is if you use a stronger type of lumber on the top chord as compared to the bottom chord. The top chord loads increase and the bottom chord loads decrease. The matrix analysis is almost as good as FEA. It's really quite cool to be able to calculate something like this just using a bunch of matrices.


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## medeek

Leaving the peak joint as a rigid connection without exploring the implications of a pinned or semi-rigid joint seem like a cop-out to me so I spent most of the day attempting to release the peak joint so that it could act as a pinned (zero moment transfer) joint. For the web members I accomplished a similar task by altering the 6x6 stiffness (k') matrix so that it only included the axial terms, thereby eliminating any shear or moment forces, making these members axial only or simple pinned truss members. However, for the top chord members it was not such an easy task. I initially tried eliminating the row of the matrix that was responsible for the far end moments (pinned end), but it some became apparent that the interplay between moments and shear forces was more than I had originally thought. I was about to accept defeat but then after spending a couple more hours digging about online I came upon a gem of a paper published in 2010 in the Electronic Journal of Structural Engineering by M. E. Kartal. This paper outlined a couple of methods for obtaining the correct stiffness matrix for semi-rigid connections. With this information I was then able to add in feature so that one can select whether the peak joint is rigid, semi-rigid or pinned. 

I then tested it for accuracy against an identical model in Solidworks Simulator for both the pinned and rigid connection at the peak joint with near perfect results. Unfortunately, Solidworks does not allow for adjusting the rigidity of connections between beams in its interface so I currently do not have the tools to test the accuracy of the semi-rigid model. However it appears to present the correct trends when compared against the other two options. If someone has a copy of ANSYS or some other reasonably high end FEA software I would be interested to see how well it will compare with third party verification.

A copy of the paper can be found here:

http://www.ejse.org/Archives/Fulltext/2010/2010v1/20103.pdf


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## medeek

*Modified Queen Truss Analysis*

Starting to work on the modified queen truss, here is the schematic for the matrix analysis of it. The structure stiffness matrix will be a 30 x 30 matrix (900 values), its no wonder they didn't do this sort of thing prior to our modern computers, imagine trying to calculate this by hand. 










Compare this to the fink truss, which has a few less webs and hence the computations are less 21 x 21 matrix (441 values)










These schematics really say nothing about which members are pinned, semi-rigid or rigidly connected. The stiffness matrix (k) for each member is what determines that. 










In my analysis I am treating all of the webs as pinned jointed on both ends and only capable of transferring axial loads (classical truss members). The top and bottom chords at panel points are treated as rigid connections. The peak joint is treated either as rigid, pinnned or semi-rigid, this is user configurable. The heel joint is treated as rigid or semi-rigid. My reasoning and justification for these model settings is based on a number of papers I have compiled on the rigidity of joints of MPC wood trusses. I have saved each one and will compile a reference list at some point to accompany the truss designer documentation.

These two papers especially the bottom one were quite helpful:

http://design.medeek.com/resources/truss/DOCUMENTS/Paper_124.pdf

http://design.medeek.com/resources/truss/DOCUMENTS/20103.pdf


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## medeek

Currently working on the plate calculations. Those will be rather lengthy but the upside is the summary is what most people will want or need, however I will show each lateral resistance, tension, shear, net section and moment check for each plated area of each joint. I'm doing one by hand first before I code it and I've already used 10 pages for the calculations and I still have to add the heel joint. I hope if nothing else people can use this app to at least better appreciate all of the checks that go into a simple truss.


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## medeek

26 pages of truss plate calculations for one simple fink truss.










It's no wonder we use computers for this sort of thing.

Now I just need to take it from this pseudo-code into Perl code with a bit of fancy logic and we've got her licked.


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## medeek

I haven't posted about the truss designer for a while, apologies for that.

Still trying to improve it as time allows. The list of upgrades and improvements was getting rather lengthy so I've created a changelog page here:

http://design.medeek.com/calculator/changelog.html

Unfortunately, I had to put a daily limit on its usage because the server was getting hammered but it is still free to use.

The biggest improvement is the ability to specify the lumber grade, size and species as well as utilize point loads. This should make this tool far more useful for those wanting to check their roof for solar panel installations etc... 

I'm still thinking about generating a REVIT model for those wanting to import the truss directly into that software or even into Sketchup. I don't know how much demand there is for that sort of thing but it would be fun to program.

I appreciate all of the support I've received over the last couple of years on this project. Suggestions/feedback is always awesome.


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## RobertCDF

I didn't read through everything but did see a few negative comments. I'll comment based on my experience. I think something like this could be very helpful as dealing with my truss guys can be frustrating sometimes. Seeing how 2x6 vs 2x4 affects things, trying other configurations, etc often leads to a "well I don't have the time right now", "why don't you just decide" and other responses along those lines. I've had to tell truss designers how to build trusses when I was told "you can't do it that way" being able to design it and send it back to them would have been awesome. In the most recent case of "you can't do it that way" he ended up being wrong, once I showed him how to do it he suddenly figured it out.


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## medeek

Added SketchUp 3D (.rb) file output for truss geometry. This file, when copied into the SketchUp plugins folder, will create a menu item within SketchUp allowing for unlimited creation of the given truss geometry within SketchUp. This plugin allows the user to specify the number of trusses and truss spacing when creating the truss geometry within SketchUp.


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## medeek

*Feedback*

Never be afraid to question the design professional. I've been doing engineering for a few years now and some residential design work but I always learn something when I get out in the field and discuss the details with the contractors, framers, and landscapers. There is always more than one way to do something. As a designer it is easy to get tunnel vision and miss a perfectly good solution to a problem. Sometimes all it takes is a hint from a second pair of eyes and then it all becomes clear. I always appreciate feedback from the people I work with. I've updated many of my structural details based on some of these conversations and will continue to do so as better methods are brought to my attention.


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## medeek

This is the same truss I used in my 28'x48' garage:










Now I need to work on the energy heel option for this truss as well as some additional logic for attic trusses in the following span ranges 16-24 feet and 30-36 feet.


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## medeek

Howe truss type is now active. 

The latest plugin version is 1.0.4. I would highly recommend downloading the latest version since I have also spent some time this morning cleaning up my code and removing global methods and variables so that I don't clash with other extensions or modules.


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## medeek

Version 1.0.5 - 10.24.2015
Added Scissor truss type, configurations: (2/2), (4/4).
Metric input enabled for scissor truss types.

In certain instances the scarf length of the bottom chord becomes less than the bearing length, the logic checks for these cases and inserts either a 3.5 or 5.5 heel wedge as required.


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## medeek

Version 1.0.6 - 10.25.2015
Added floor truss type, Modified Warren - System 42.
Metric input enabled for floor truss types.
Top and bottom bearing option enabled for left and/or right end of floor trusses.
Ribbon cut option (top) enabled for left and/or right end of floor trusses.










One central chase that can be position relative to the left end of the truss. If the chase becomes closer than 1/4 the span to either end it will flag the user and re-position. Also some logic to check the chase size to span ratio and absolute max. chase size (24").

System 42 or 32 floor trusses using the modified warren configuration which seems to be the most popular for this type of floor truss. Top bearing configuration includes an additional slider for extra strength and a vert. Note the change in diagonal directions when comparing a top to bottom bearing floor truss, I was not aware of this until studying them in some detail. Typical panel length is 28" but this can also be set by the user to any value.


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## medeek

Various configurations of dual pitch trusses:


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## hdavis

Man, have you been busy!:thumbsup:


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## medeek

*3 Point Input*

Version 1.0.7 is now live. The big improvement is the ability to click with the mouse at three corners and place the truss set without any additional rotating or translating.

In literally seconds I can now put a floor and a roof on 4 walls using the truss plugin and the Homebuilder plugin:










Of course the gable walls are not quite right but you get the idea. For generating quick visuals I think SketchUp takes the prize. 

I'm still an AutoCAD guy though when it comes to generating 2D drawings.


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## digiconsoo

This is really cool!

I really appreciate the "never be afraid to question the engineer" attitude.

Most of them certainly want you to be afraid to question them........


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## Warren

I have seen this thread for a while, but never really looked into exactly what you were up to. I just ran a sample truss, and boy it was really easy. We do a ton of work with roof trusses. It will be nice to have something like this to see what is possible.


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## hdavis

Warren said:


> I have seen this thread for a while, but never really looked into exactly what you were up to. I just ran a sample truss, and boy it was really easy. We do a ton of work with roof trusses. It will be nice to have something like this to see what is possible.


Same here. I can use software to size beams, etc as a first cut to sse what's a practical approach, but trusses have been out of reach, except for the canned AG trusses.


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## medeek

The reason trusses have been out of reach is because the truss plate manufacturers have a tight grip on it and will not release a version of their software so guys like you and me can run some scenarios on trusses. As an engineer you would think it would be useful to have such a software especially when it comes to retrofitting roofs with solar panels etc... but the Mitek, Alpines and Simpson companies out there will only allow their software to be licensed to truss manufacturers who purchase their plates. 

I've addressed this issue before at this page:

http://design.medeek.com/resources/truss/study1/attictrussanalysis.html

If I had more time and money I could probably produce a product that rivals the best of the truss softwares out there. However, I am just one person with a very limited budget and hence even more limited in spare time to work on this project. At best I will keep on developing my truss calculator in hopes that I can force the hand of the big boys to release a version of their software to the design community and general public.


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## medeek

*Version 1.0.8 - 11.04.2015*
- Added Weyerhauser TJI® I-joists: 110, 210, 230, 360, 560, 560D.
- Rim joist option enabled for TJI floor joists.



















Only a rectangular configuration is available currently. If I can figure out how to code a polygon version of this that would be much more impressive (ie. pick the points that define the perimeter of the foundation and the plugin generates the complete floor layout).

This is straying a bit from trusses but I figured if I'm going to include floor trusses I might as well make floor joists available as well, just a small bit of code to get there.


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## medeek

Just playing around with SketchUp a bit today and trying out the new sheathing, rakeboard and fascia capabilities in the Plugin.

The roof of this simple structure took all of 10 seconds to create, the rest about 20 minutes. I didn't realize Simpson Strongtie hardware is available in the 3D warehouse, good to know.










I'm not going to say anything about lateral bracing of this structure, just modeling for fun.



















One can go so far as to put all of the H1 ties in. I could waste an entire day messing around in this software, way too much fun.


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## medeek

Outlookers enabled under advanced roof options for Common, Scissor and Attic truss types.











Not really sure what is the best treatment of the outlookers at the peak of the roof and consequently what is best way to space them. Measure them from the peak or the eave/fascia?


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## medeek

Outlookers get a little complicated depending on whether they are structural or not. Typically around here (Ocean Shores, WA) we see them at 24" on center and they are usually structural. The top chord of the truss is dropped either 1.5" or 3.5" depending on if they are oriented horizontally or vertically. With structural lookouts the first lookout from the eave is usually non-structural since the dropped top chord truss will have a special slider attached to top chord to achieve the overhang. See image below:










Usually the sheeting goes on starting at the bottom so based on that the lookouts would be measured from the bottom edge of the sheeting so that they line up with the seams every 48".

I've seen a single vertical placed the ridge when the outlookers are vertical however what is common practice when the outlookers are horizontal?

Notice the different configuration of the top chord when the drop is only 1.5" (oriented flat).










If the overhang is zero then this slider or splice goes away.


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## medeek

*Version 1.2.4* - 01.08.2016
- Plugin integrated with the Medeek Truss Designer.
- 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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## medeek

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/resources/beam/beam_calculator.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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## medeek

*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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## medeek

Engineering Video:








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

https://3dwarehouse.sketchup.com/model.html?id=u6c602b47-40bb-4349-9e0e-0917746ab90a


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## medeek

Valley Truss Set:


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## medeek

First tutorial video:


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## medeek

Hip Roof Framing:






SketchUp model used in the video can be found here:

https://3dwarehouse.sketchup.com/model.html?id=u53e50317-d46f-40dd-a95f-c50b1d51302d


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## 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.


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## hdavis

medeek said:


> My question is at what length of fastener exceeding the total thickness can I functionally clinch the nails and consider them in double shear.


Once the protrusion becomes less than 3-4 times the nail diameter, it becomes difficult to get a good clinch. You may have to start the bend with Vice Grips, and then pound it over at 3X-4X. That's my experience, just clinching with a hammer and backer.


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## Fouthgeneration

Pretty impressive software. But I think you are reinventing the wheel somewhat on the fasteners, 99% of what you are doing you should be able to dig out of old USDA tests etc....

Obviously after the I-35 bridge failure, gusset design and detailing shouldn't be ignored, and very long lifespan structures deserve a higher level analysis, as some fasteners will actually speed biological decay in wood if they're in certain moisture ranges...

But the less is more certainly applies to embedded wood fasteners, 

In the end it will be economy of assembly that will govern the type and manner of hardware installs performed in the field. Maybe some stainless or carbon fiber bands? with a couple of nails for easy tensioning of the bands?

The tension splices would seem to need the most care in designing a system that is idiot resistant for long term performance and maintaining a adequate safety factor in use and installation.


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## hdavis

Fouthgeneration said:


> Pretty impressive software. But I think you are reinventing the wheel somewhat on the fasteners, 99% of what you are doing you should be able to dig out of old USDA tests etc....


I think that's what he's doing, but he wants to limit the use of clinchers to practical situations - no sense in allowing a combination that just isn't going to work out.


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## medeek

Assuming only a double shear connection which would prevent excessive nailing of the main truss member and splitting, the following gusset plate thickness and nail combinations would be allowed:

Gusset Plate Total Thickness Nails
3/8" = 2.25": 10d Commmon, 10d Box, 10d Sinker
7/16" = 2.375": 10d Commmon, 10d Box, 10d Sinker, 12d Sinker
15/32" = 2.4375": 10d Commmon, 10d Box, 10d Sinker, 12d Sinker
19/32" = 2.6875": 12d Common, 12d Box, 12d Sinker, 16d Box, 16d Sinker
23/32" = 2.9375": 16d Box, 20d Sinker

This would allow for at least 3 x diameter for clinching, and also does not violate NDS 2012 Sec. 11.1.6.5.


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## medeek

Fouthgeneration said:


> Pretty impressive software. But I think you are reinventing the wheel somewhat on the fasteners, 99% of what you are doing you should be able to dig out of old USDA tests etc....


Current engineering practice uses the yield limit equations (Sec. 11.3 NDS 2012) found in the AWC National Design Standard to check the capacity of dowel type fasteners like nails. This is the standard I will use to comply with current code and engineering practice. Rather than use the tables I will have to calculate 4 separate equations for each joint in double shear (Im, Is, IIIs, IV). It sounds like a lot of work but once you set it all up in the program the computer does the number crunching. To manually calculate all of the numbers for a typical truss design would probably take me 4-5 hours, with a programmed solution, 10 - 20 seconds to enter the inputs and your done.


----------



## Fouthgeneration

I don't understand even listing 3/8" materials to join two x boards, why even go there?

The thinner gusset plates having to be wider than the 2xs are. And needing more # of fasteners to equal the strength of the same # in the 3/4" or thicker boards.

All other things being = fewer fasteners = cheaper/faster truss for the $, two out of 3 of the Engineering triangle. 

Surely as with reinforced concrete, a congestion/splitting factor/percentage applies?
Most of the rules for maximizing a riveted strap connection to another could be applied almost without change... 

Splices that don't molest the wood would seem to be the way to improve truss performance over the current levels of trusses assembled with penetrating fasteners.

In North America in-spite of Obama et al, field labor is still several times the material cost of the truss splices.

Wouldn't lab tests of actual trusses(differing splice connections) trump any equation? the Map(Math) isn't the World.....


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## hdavis

Fouthgeneration said:


> I don't understand even listing 3/8" materials to join two x boards, why even go there?


Probably because it might be useful to someone. I know I'm interested in it.


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## medeek

Realistically I probably would not drop below 7/16" for the gusset plates but for smaller span trusses, a 3/8" thick gusset may be all that is required. The idea is to offer as many practical options as possible and allow the user to try various scenarios and design parameters.


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## medeek

An initial design concept:


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## 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.


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## Fouthgeneration

The fewer the Penetrations the closer the final assembly would be to the original unmolested state/100 % of its strength of the member of the truss.... Thus less is more in general.

Clinching nails, if it cuts the # of invasive fasteners is a no- brainer, but the gauge of the nail/wire and the head style would effect the strength of the tool side of the splice, most framers seem believe in "sunk" heads.

the only time I ever field built trusses is when we had Used/ "free" lumber... We almost been ahead to burn the wood....

An adhesive that can take a century or two of 300 degrees + and cold swings would add a lot of value to the joint.

Are single sided gussets practical? what about just lap splicing with the 2cd board.....

Can one spec trusses that aren't made from built up lumber for the three out side pieces?


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## medeek

*Version 1.2.7* - 01.26.2016
- Added advanced roof options for hip rafter roof (sheathing, fascia).










https://3dwarehouse.sketchup.com/model.html?id=u3b08ddf6-b8be-405c-9ae6-912866e7a252


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## Fouthgeneration

Are bird's mouthed straight rafters appropriate in an air conditioned building? Ever?


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## medeek

*Complex Hip Roof Framing*

I've uploaded a test L-Shaped structure with a hip roof:

https://3dwarehouse.sketchup.com/model.html?id=u8d384878-941b-4df9-a8c9-8bba849765bb

I've created both hip roof primitives with the plugin, that was the easy part. 

I then placed a valley rafter with its centerline (top) inline with both roof planes. I think I've got it right. What I am unsure of however, is the best way to terminate the framing at the intersection of the valley, lower ridge and flying hip. Once I have a handle on how a carpenter would actually construct that junction I think I can proceed to start work on a secondary roof module for both hip and gable rafter roofs.

The secondary roof module will allow one to add secondary roof geometry to a main roof and have it automatically adjust the rafters accordingly.


----------



## medeek

One method of framing this roof configuration is to extend the lower ridge past the joint until it meets the next jack rafter, then the flying hip and valley are miter cut to meet the lower ridge. 

I've created a version of the model above with this method of framing at the flying hip/valley/ridge joint:

https://3dwarehouse.sketchup.com/model.html?id=u06386a43-c138-4e90-8b2c-779fd2b63705

What is the thinking on this method of framing this particular configuration?

My other concern is the way I have the valley rafter miter cut where it meets the fascia and the corner of the building wall (top plate). Is there a more practical way or better way of making those cuts?


----------



## medeek

Compare Rev 2 with Rev 3:

https://3dwarehouse.sketchup.com/model.html?id=u83ae5e44-1b19-4c09-8586-93988684289e

This version of Hip Roof 4 has the flying hip extending as a full hip to the exterior wall and then the lower ridge framing into it with the valley rafter framed in last.


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## medeek

Rev. 5 is a slight variation of the previous roofs. I have shifted the secondary roof over by 24" to create a T-shaped building. The question is how to best frame the long and short valleys:

https://3dwarehouse.sketchup.com/model.html?id=uf6d4e102-46d7-44b2-bfa2-b8ac12b6da21


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## medeek

The intersection of the supporting valley rafter, valley rafter and lower ridge I had framed incorrectly. The corrected method is shown below:










Also note that the segment of the supporting valley rafter between the upper ridge and lower ridge would need to be beveled or "backed" otherwise it clashes with the sheathing. I noticed this when I originally added the supporting valley rafter but confirmed my suspicion when perusing DeWalt's carpentry and framing handbook this morning. I probably should have pulled this book out before beginning this study but it only confirmed everything I had managed to discover myself once I started examining the model.


----------



## medeek

This is my first crack at a dutch gable hip roof framed with rafters:










Without the sheathing:










Please examine the model here:

https://3dwarehouse.sketchup.com/model.html?id=u060d4827-fbb5-400e-8270-0b244d958750


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## medeek

*Dutch Gable Rev. 3*

Dutch Gable Rev. 3:

Doubled up gable common rafters but the dutch ridge/ledger is sandwiched between them. Found a paper by Larry Haun, Mar. 1995 "Framing a Dutch Roof" that was published in Fine Homebuilding magazine, that describes a very similar method of framing.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=ude19cd3c-e059-42e0-8e7d-2b0b6b0852a8

Disregard the common rafter sizes they are undersized but look at the method of sandwiching the dutch ridge/ledger between the last common rafters. I would probably also install some blocking between the double gable common rafters. I'm also not showing all of the ceiling joists and bird blocking etc...

If the roof gets large enough then one could go to a double ply dutch ridge, or even a deeper LVL member, assuming there is no internal support available from internal walls.


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## medeek

*Version 1.2.8* - 02.02.2015
- Added Shed Rafter Roof with Ledger (all advanced options enabled).
- Added ceiling joist option for Shed Rafter Roofs.
- New submenu item and toolbar icon added for secondary (minor) roofs.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u972818f0-96f0-4f85-9781-087a2db95199

I used this option to create a monitor style roof line but it can also be used for porch roofs, carports etc... I still need to add a standard shed roof with and upper and lower birdsmouth cut.


----------



## medeek

Testing the real world application of the Medeek Truss Plugin. This model combines a double fink truss, raised heel fink truss, monopitch truss and shed roof with ledger. While creating the shed roof special attention to the birdsmouth cut was required to ensure that the fascia height of the rafters and trusses lined up. Also note the use of the raised heel type truss on the upper roof portion. Structural outlookers were specified for all gable overhangs. 

5:12 pitch roofs with rafters and trusses 24" o/c. I did not apply a level cut to the rafter overhangs but that would probably be a given. Span of the double fink is 48 feet with 2x6 top and bottom chords.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u98040448-af54-4d79-af30-a3aefca9b941

If anyone has some real world applications using the plugin that they are willing to share I would be very interested to see how it is being used and it would also give me some direction for further development and improvements.


----------



## medeek

The official manual is now a work in progress:
http://design.medeek.com/support/trusspluginmanual/mainpage.html


----------



## medeek

*Version 1.2.9* - 02.12.2015
- Added Shed Rafter Roof (all advanced options enabled).
- Added ceiling joist option for Shed Rafter Roofs.
- Initial menu now defaults to last picked option of session for that sub-menu item.

A typical application might be a clerestory roof with a upper shed roof and lower shed roof with a ledger board:










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u0b2dd5bc-605d-467c-a6bb-449bb54e76e6


----------



## medeek

I've been looking at a number of garage designs recently that employ an attic or storage truss. I'm finding that a lot of them tend to use raised heels to allow for more head room while having a lower roof pitch (ie. 6/12 - 8/12). I'm thinking about adding in raised heels for the attic truss type in the plugin. 

A quick mock up would look something like this:










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u208d64e3-ddcf-4923-8dfb-d507185fa663

Ignore the unbalance in the panel lengths, in practice and in the plugin they will be properly balanced. 

What I do have a question on is the use of a top chord splice as shown in the above image so that the overhangs do not have to be as deep as the top chord in the non-triangulated region of the truss. I have never seen a splice used on a attic truss with a raised heel, I don't see why it can't be done but it is always nice to have a confirmation that someone else is doing this sort of thing in practice.


----------



## medeek

*Version 1.3.2* - 02.23.2016
- Added Dualpitch truss type, configurations: (2/2-3/3).
- Metric input enabled for dualpitch truss type.
- Advanced options enabled for dualpitch truss type.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u9b6a5e53-76c4-4c9b-bce3-aaa8ffba4c36


----------



## medeek

*Version 1.3.4*

*Version 1.3.4* - 03.02.2016
- Corrected a bug in the metric unit template module.


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## medeek

*Version 1.3.5* - 03.04.2016
- Added Bow Barrel truss type, configurations: (8/8).
- Metric input enabled for bow barrel truss type.
- Corrected a bug with the webs of the bowstring truss type.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u754b5fc3-c3ea-48cb-9f13-24c92ae39d97

Gable end option is also available (not shown in image above for clarity) for this truss type.


----------



## medeek

Another study of hip roof framing where unequal pitches meet at the hip. The birdsmouth cut is 3.5" for all jack and common rafters. The hip rafter is dropped and off center so that it lines up with the roof planes. The hip roof combines a 12:12 pitch with a 6:12 pitch.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=uc12480ec-9330-464b-93eb-56bc73878207


----------



## medeek

*Version 1.4.0* - 03.15.2016
- Added LP Solidstart® I-joists: 450, 530, 18, 36, 56.
- Rim joist option enabled for LPI floor joists.


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## medeek

*Version 1.4.1* - 03.16.2016
- Added Soffit Cut within Advanced Options for Gable Roof and Gable Roof w/ GLB.


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## medeek

I've been considering transition trusses and what it might take to add them into the plugin. Below is a quick study of this type of roof. I am curious to know if a common trusses is butted up next to a transition truss for sheathing purposes. Also notice the scissor transition, this situation is a little complicated, not exactly sure how to deal with it.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=ue1772e6a-eb97-4775-b9f8-d12e3e134ba3


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## medeek

This is a re-visit of the unequal pitch hip roof a few days back. Larry Belk, an experienced architect whose advice I highly regard, has suggested that an alternative way to handle this type of roof is to raise the top plate and thereby allow the overhang to remain constant around the roof:










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u24f241c6-d493-45cb-9506-d025d7ebd795

Compare with hip roof 7: 










and model:

https://3dwarehouse.sketchup.com/model.html?id=uc12480ec-9330-464b-93eb-56bc73878207

A few things pop out at me here. 
First the raised top plate method allows the constant overhang with the continuous fascia, overall this is more aesthetically pleasing.
Second the hip rafter is no longer at the corner but is jogged in some amount onto the higher wall.
Third, the higher wall actually is protruding through the sheathing of the lower pitched roof in the model. Obviously the higher wall needs to be trimmed back some to deal with this.

For the plugin I think I will go with option 1 above initially but at some point it would be good to have a checkbox that allows one to choose either of these two options, the code is going to get ugly.


----------



## medeek

*Version 1.4.2* - 03.19.2016
- Added energy/raised heels for attic trusses (1 variant: vertical w/ strut).
- Addressed some minor usability issues with the attic truss menu and options.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u4f64fd8b-160f-49ce-815d-a66991527cdb

I've had quite a few people asking for this update so stayed up most of the night and knocked it out. Note, that the raised heel option is currently limited to attic trusses with a span of 24 ft. or greater. The reason for this is the way my logic currently works with spliced top chords. If this becomes an issue I will spend some more time on it to encompass attic trusses with a lesser span. I still do not have the gable truss, metric input or structural outlookers for this truss type, yet more items for the "todo" list.


----------



## medeek

Thinking about dormers today and attic trusses:










View model here:

https://3dwarehouse.sketchup.com/model.html?id=ud50cb83e-54fc-42b0-9b57-0a5691b1c678

2-ply girder trusses on each side of the dormer with ladder framing between. I haven't bothered to show all of the main floor framing geometry (doors, windows, stairs etc...) My question is what would be the best route for the infill framing above the dormers.

1.) Ladder frame perpendicular to trusses.
2.) Install a ridgeboard hangered between the girder trusses and a lower header and install rafters parallel to the trusses?

Note that the manual creation of the dormers took about an hour whereas the attic truss main roof and dormer roof were created with the plugin and only took about 5-10 minutes. A dormer routine would be useful.


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## Fouthgeneration

Why would any one build a money pit like your last post? Only by underpaying for all the extra hand labor can such structures be built...

Plus they are energy pigs with 2 and 3 times the surface area of cheaper to build and more usable space designs.

Shed dormers would be by far cheaper and give more volume and area then the uber maintenance dormers.

I don't see constant eave depth as even being desirable regarding solar gain on ranch houses, an 3' or 40" overhang can really lower one AC bill in the summer while letting the light and warmth in during the winter.

Does your software design the transfer blocking from the roof diaphragm to the shear walls, wing bracing/rat runs?, diagonal bracing for the corners. recommend tornado/hurricane ties/strapping to the footings? blocking required at ceiling adjacent the gable to end wall plates? plate sizing and stud spacing for finished attic spaces loads?
I could easily see a garage storage bonus room going well over 200 lbs a square foot with an average pack Rat shade tree mechanic. 

Is there any data regarding designing roofs shape and styles that are more brush fire resistant for the silly out West that refuse to burn off the brush surrounding their houses every few years....


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## hdavis

Fouthgeneration said:


> Why would any one build a money pit like your last post?


That's easy - some styles use that type of dormer / roof, and it's very popular up here. They aren't the cheapest to build for sq ft living space, but people are willing to pay for the style. Regional market preferences....


----------



## Builders Inc.

*


Sent from my iPhone using Tapatalk


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## medeek

A basic algorithm to convert a common gable truss into a transition truss should not be to much problem. However, to make it handle all cases would become difficult if you include raised energy heels, drop top chords and scissor trusses in the mix. Consider the two examples below:


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## Fouthgeneration

So, the vertical chord part of trusses shown are 'gable' ends?...Nailers for firewalls/sheathing?

Is there a conventional framed truss to be installed adjacent to these 'transition trusses? or load bearing wall under them?

The Very deep Energy trusses would need special details at their plate connection as they form a "Knee" wall state with out careful design/installation.

For very deep Energy truss "heels" alternate frame methods such as a ledger board, ballon style framing maybe? Or a dropped ceiling diaphragm to allow adequate space for insulation with out the structural flaw of a mid wall break.


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## medeek

*Version 1.4.3* - 03.20.2016
- Added Scissor truss type, configuration: (6/6).
- Added energy/raised heels for scissor trusses (2 variants: wedge and vertical w/ strut).
- Addressed some minor usability issues with the scissor truss menu and options.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u8ca4bf44-f28a-481e-8c1e-b53de30e3696


----------



## medeek

Polynesian 4/4 truss is working:










However, I haven't released this latest update yet, I still need to enable gable end trusses and advanced options for this truss type before it is ready for prime time.

The inputs are similar to all other truss types except you have two top chord pitches and a pitch break length measured from the left butt cut of the truss.


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## medeek

*Version 1.4.4* - 03.21.2016
- Added Polynesian truss type, configurations: (4/4).
- Metric input enabled for polynesian truss type.
- Added gable end trusses for polynesian truss type.










I'm not sure where this type of truss is commonly used but whenever I see one I think of a bus stop or train station:










Advanced options are not yet enabled for this truss type yet, so sheathing, fascia, rake will have to come later.


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## medeek

Using a typical Barrel Vault 8/7+4 or 8/7+2 configuration I come up with the following triangulations. I'm sure there are other methods of configuring these webs but for the purposes of the plugin I think these solutions will suffice for now:










High Resolution PDF copy here:

http://design.medeek.com/resources/truss/BARREL_VAULT/BARRELVAULT_STUDY1_REVA2.pdf

Based on this matrix I've been able to come up with a simple algorithm for the triangulation of this truss type. I'll admit the barrel vault truss is one handsome devil.


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## medeek

A 9:12 barrel vault truss with a 16' wide barrel:


----------



## medeek

*Cambered Trusses*

Another look at the cambered truss:


----------



## medeek

*Version 1.4.6* - 03.26.2016
- Added Cambered truss type, configurations: (6/X).
- Metric input enabled for cambered truss type.
- Added gable end trusses for cambered truss type.










Six variants of the (6/X) configuration dependent on the ratio of the camber width to span. Notice that in all cases the top chord has six panels, the bottom chord varies from 4, 5 and 6 panels.

View model here:

https://3dwarehouse.sketchup.com/model.html?id=ued7e0d19-2843-4b3a-9786-3c15cf876fdf


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## medeek

*Version 1.4.7* - 03.28.2016
- Added Cathedral truss type, configurations: (4/X, 6/X).
- Metric input enabled for cathedral truss type.
- Added gable end trusses for cathedral truss type.










Note, that not all configurations have webs enabled however the top chords, bottom chords, gable end trusses and all advanced options are enabled.


----------



## medeek

To further clarify the framing details with regards to attic trusses and structural outlookers I've created a sample model with a proposed dropped top chord gable end attic truss:










Please download and review the model here:

https://3dwarehouse.sketchup.com/model.html?id=u8c3afc5c-482a-41ea-b223-988b1cccd8bc

I've also included the infill wall framing to help put everything into reference (light green).

Is this the appropriate way to frame an attic truss (gable end) with structural outlookers?


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## medeek

Six possible end details for a flat truss (Pratt 4 panels), there are probably others but these seem to be the most common:










1.) Mansard w/ Parapet
2.) Parapet
3.) Mansard
4.) Overhang
5.) Cantilever
6.) None

Both Mansard configurations can also have an optional overhang as shown. The Parapet configuration should allow for customizing the thickness of the parapet wall.

View model here:

https://3dwarehouse.sketchup.com/model.html?id=ude4e9b15-f67e-40de-a99f-97d2044182ad

This truss type with its many end configurations would work well with an HTML UI, that is the direction I will be going with future user inputs and interfaces since the ability to customize is unlimited.

With the flat trusses I will initially offer both Howe and Pratt with the ability to utilize a low slope or zero slope.


----------



## medeek

*Mod Fan Truss Type*

*Version 1.4.8* - 04.01.2016
- Added Mod Fan common truss type.
- Structural outlookers (vert. & horz.) enabled under advanced roof options for Common (Mod Fan) truss type.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=u3cf3d051-4d02-4490-af81-5693296cca33

With the addition of the Mod Fan (Triple Fan) the line up of common trusses is complete. I still need to add in raised heels and structural outlookers for some of the configurations. 

Theoretically I could add in additional configurations of the Fink and Howe truss types for extremely large roofs but the largest I've ever seen is a raised heel Quad Fink (10/9). Large spans beyond 70'-80' are probably not practical as far as a single span common truss roof. At that point you pretty much go with large flat roofs with interior columns and girders and all steel construction (think Walmart or Cosco).


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## medeek

*Version 1.4.9* - 04.04.2016
- Added Tray truss type, configurations: (AUTO).
- Metric input enabled for tray truss type.
- Added gable end trusses for tray truss type.


----------



## medeek

*Mono Scissor Trusses*

*Version 1.5.0* - 04.11.2016
- Added Mono Scissor truss type, configurations: (2/2, 3/3).
- Metric input enabled for mono scissor truss type.
- Added gable end trusses for mono scissor truss type.
- Structural outlookers (vert. & horz.) enabled under advanced roof options for Mono Scissor (2/2, 3/3) truss types.










When the raised heel option is selected the pitch of the bottom chord may equal the top chord creating a half vaulted parallel chord truss.

View model here:

https://3dwarehouse.sketchup.com/model.html?id=8e90b148-e241-4c88-b8b4-83c21ec12a3d


----------



## medeek

Updating the hip roof module so that an appropriate wireframe is displayed while using the roof positioning tool:










I will roll a revision once I've finished updating all of the rafter roof types with updated wireframes (preview graphics).


----------



## medeek

*Version 1.5.1* - 04.16.2016
- Added Dutch Gable Rafter Roof (all advanced options enabled).
- Added wireframe (temporary) graphics to the roof positioning tool for rafter roofs.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=614d542d-8dcc-4f2f-bbdc-fd4bc4c1f1e7

I still need to setup ceiling joists for hip and dutch gable roofs.


----------



## medeek

A nested dutch gable roof created with the plugin. The roof is initially generated by creating three dutch gable primitives and then deleting and trimming certain elements. The most time consuming is the creation of the two valley rafters. I think it might be helpful to have some sort of valley rafter tool if I can figure out a good way of doing that.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=2676e970-a79e-40a3-8c77-63208c9d93ef


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## medeek

Per user request:

*Version 1.5.2* - 04.18.2016
- Added energy/raised heels for small span attic trusses (less than 24 ft.), 1 variant: vertical w/ strut.
- Added some additional logic to improve the triangulation of the upper attic of attic trusses.










When I get some more time I will add in slider and wedge raised heel options for the attic truss type but at that moment it is low priority since most users seem to favor a fairly tall raised heel when utilizing it with attic trusses.


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## medeek

*Version 1.5.3* - 04.20.2016
- Added Mono Cathedral truss type, configurations: (2/2, 4/4).
- Metric input enabled for mono cathedral truss type.
- Added gable end trusses for mono cathedral truss type.
- Structural outlookers (vert. & horz.) enabled under advanced roof options for Mono Cathedral (2/2, 4/4) truss types.
- Added Mono Scissor truss type, configuration: (4/4).










View model here:

https://3dwarehouse.sketchup.com/model.html?id=2ba29c11-a7b2-4913-a758-c005eb1288f9

I manually modeled this truss type about two months ago and I have been meaning to add it in, finally got it done tonight.

Manually created model here:

https://3dwarehouse.sketchup.com/model.html?id=u5c030ac2-f2e4-4c8d-8d9b-67bfa780ee7f


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## medeek

*Version 1.5.4* - 04.21.2016
- Added a graphical user interface (GUI) for the selection of the truss type in the "Draw Roof Truss" sub-menu.
- GUI can be toggled with previous drop down menu within global settings.



















As you can see there is only one global setting at the moment but now that I have the interface and back end properly setup it won't take much to add in a number of other global values. At some point I will probably have enough parameters that I will need to enable some sort of tabbed html front end for the global setting menu.

With html web dialog boxes I am not sure how well they work on a Mac, the whole sync vs. async issue is a real problem for web dialogs and Macs. I only test on a PC so I can't guarantee 100% compatibility on a Mac. So far I haven't had too many complaints.


----------



## medeek

Here is a preview of the Geometry Input (GUI) menu for the upcoming gambrel attic truss.










Notice the preview pane which gives a basic profile of the truss and attic space. I still need to add some dimensions and some other symbols (pitch, bearing walls, etc...) to the preview graphics but it is mostly there and functioning quite admirably. 

The GUI is html with javascript and SVG (scalable vector graphics) for the image. The nice thing is that changing any of the inputs will instantly update the dimensions and preview image allowing one to fine tune the truss geometry before proceeding further. For gambrel roofs this ability to adjust the proportions of the roof relative to each other is very important in my opinion. See my previous gambrel study here:

http://design.medeek.com/resources/truss/gambrelroofstudy.html


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## medeek

*Version 1.5.5* - 04.29.2016
- Added Gambrel Attic truss type, configurations: (AUTO w/ piggyback trusses).
- Added a graphical user interface (GUI) for gambrel attic geometry input.










A reset button would be useful to return the GUI to the default values. There is still a lot of work to be done with the gambrel attic truss type:

- Advanced Options
- Gable Trusses
- Default or Reset Button
- Metric Input

View model here:

https://3dwarehouse.sketchup.com/model.html?id=fc8be11c-8bb1-4e60-a73e-5ba62628ae95


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## medeek

*Version 1.5.7* - 05.15.2016
- Added Scissor truss type, configurations: (4/2, 6/4).
- Structural outlookers (vert. & horz.) enabled under advanced roof options for Scissor (4/2, 6/4) truss types.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=620e816e-d809-4732-a19f-e425b4cc17fc

I also updated the pause in the truss selector GUI from 700 ms to 400 ms. Still more work to be done with raised heels and structural outlookers for some of these configurations but its getting close.


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## medeek

*Version 1.5.8* - 05.22.2016
- Added metric input for Gambrel Attic truss type.
- Added a graphical user interface (GUI) for metric gambrel attic geometry input.

Gambrel Attic (metric) GUI










I also show the industry standard feet-inches-sixteenths.


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## medeek

Various configurations of a 16' King Post Truss:










View model here:

https://3dwarehouse.sketchup.com/model.html?id=d38c0061-b812-499a-b02a-70c43148d958

With a raised heel note the use of either a wedge, slider or vertical web with strut.


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## Mr Latone

Thank you for these useful posts


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## medeek

*Coffer Trusses*

*Version 1.6.1* - 06.11.2016
- Added Coffer truss type, configurations: (AUTO).
- Metric input enabled for coffer truss type.
- Added gable end trusses for coffer truss type.
- Structural outlookers (vert. & horz.) enabled under advanced roof options for Coffer truss type.
- Building parameter menu (2nd) and advanced options menu for trusses now default to last picked options of the session for that sub-menu item.


Various configurations of a 40' coffer truss shown below:










The web triangulation algorithm automatically determines which configuration is appropriate based on the span between panel points. This simplifies the geometry input menu but does take some control from the user.

View model here:

https://3dwarehouse.sketchup.com/model.html?id=a9f2e281-557d-4d13-a9ad-64bdfdd078f4


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## medeek

Modified an existing truss roof to make it a half hip truss set:










View model here:

https://3dwarehouse.sketchup.com/model.html?id=6e2633ca-ebb2-4597-87e9-ba41b47a636f

This will be my first venture into more complex truss systems. I figured I would cut my teeth on the half hip (Jerkin Head, Tudor Hip) truss set first before attacking the more complex full hip variants of which there are many.

After sketching this model up and examining the geometry I now have a number of questions:

1. Are my roof planes correct? Note that I have drawn the apex of the hip roofs at the edge of the last full truss and not at its centerline. Not entirely sure what is common practice in this regard.

2. I've shown some non-structural outlookers along the rake. What would the outlookers along the half hip portion look like?

3. If I use structural outlookers how would those be framed in over the hip section?

4. Does the apex of the half hip typically coincide with the next truss or could it land somewhere between trusses? ie. the half hip length is some multiple of the truss spacing.

5. Is the hip section usually the same pitch as the rest of the roof? There is really no reason why it has to be.

6. As the length of the half hip increases the depth of the gable end truss decreases as does the first inboard truss. What is the practical limit for the minimum depth of the first inboard truss?

7. Does anyone have some shop drawings of this type of truss set that I can study?


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## medeek

Hip Truss Algorithm:


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## medeek

*Dormers*

*Version 1.6.3* - 06.19.2016
- Added Gable Dormers to the Minor Roof Sub-Menu (dormer walls only).

For now only the walls of the dormer are created:










View model here:

https://3dwarehouse.sketchup.com/model.html?id=e17866e5-2e1d-4fb7-8203-fcb6484e8f08

I am still ironing out the details on how to best model the roof geometry. I will probably offer either a rafter or truss option. Other details such as multiple windows will also come later.

For now please test the metric and imperial wall creation. I will probably need to post a tutorial video on how to use this feature since it involves selecting the main roof plane (top of a rafter or truss) and then two points that define the width/exterior corners of the dormer.


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## medeek

Testing the dormer (wall) feature out with a gambrel attic truss:










These dormers have a typical gable profile but it might be useful to have a gambrel dormer option as well to match with a gambrel style roof. Note that I have not shown all of the ladder framing in the model. On a roof like this it could get quite extensive.

To generate the dormer roof I just used my rafter roof feature and then trimmed the elements back manually. 

View model here:

https://3dwarehouse.sketchup.com/model.html?id=315004e6-6c2e-427e-981e-dc891371c77c

https://www.kubity.com/p/uCN2F6


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## medeek

Same barn with a few more details. For gambrel attic advanced options I should also include the option for a crow's beak as shown in this model and the option to set the extension.










View model here:

https://3dwarehouse.sketchup.com/model.html?id=1d1a6c57-08c4-46a4-a93e-9ae28b9f477e

https://www.kubity.com/p/hNVovS


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## medeek

*Version 1.6.4 - 06.27.2016*
- Added roof return option within the advanced options menu for common, scissor and vaulted trusses, configurations: (HIP).










View model here:

https://3dwarehouse.sketchup.com/model.html?id=790b256d-72fe-46c9-b49c-dd7da0209a02

This option is available for most typical triangular shaped trusses.

I will be adding the gable and full return at a later date, currently only the hip return is available. Another limitation is that the return roof pitches currently default to the main roof pitch. I need to add some additional code that will allow the pitch of the return portions to be set independent of the main roof pitch.


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## medeek

12:12 main roof with a 8:12 hip roof return. The interesting part is the hip rafter 
where the return meets the main roof plane. The dropped hip rafter is off center so that it supports the sheathing from both planes. The calculations might prove challenging.










Typically the return pitch is less than or equal to the main roof pitch. In fact I don't think I've ever seen a return with a pitch greater than the main roof.


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