Truss Calculator

medeek · Oct 10, 2013

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.

medeek · Oct 3, 2015

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.

RobertCDF · Oct 3, 2015

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.

medeek · Oct 3, 2015

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.

medeek · Oct 3, 2015

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.

medeek · Oct 17, 2015

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.

medeek · Oct 21, 2015

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.

medeek · Oct 24, 2015

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.

medeek · Oct 26, 2015

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.

medeek · Oct 27, 2015

Various configurations of dual pitch trusses:

hdavis · Oct 28, 2015

Man, have you been busy!:thumbsup:

medeek · Nov 4, 2015

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.

digiconsoo · Nov 4, 2015

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........

Warren · Nov 4, 2015

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.

hdavis · Nov 4, 2015

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.

medeek · Nov 5, 2015

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.

medeek · Nov 5, 2015

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.

medeek · Nov 9, 2015

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.

medeek · Nov 22, 2015

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?

medeek · Nov 22, 2015

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.

Truss Calculator

medeek

medeek

RobertCDF

medeek

medeek

medeek

medeek

medeek

medeek

medeek

hdavis

medeek

digiconsoo

Warren

hdavis

medeek

medeek

medeek

medeek

medeek

Top Contributors this Month

Recommended Communities