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Truss Designer 2015 Updates


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Its been a while since I've posted on this board. I am still plugging away at the truss calculator that I started back in 2013.

Under "Advanced Options" you can now specify the lumber species, grade and size for the top chord, bottom chord and webs, this should allow one to check any fink truss "as built". I still have not configured a method to specify the plate sizes at each joint but that should not actually be that difficult. For now the plate are auto sized until the JSI requirement is met. This is probably the most significant update to date since it allows one to "check" a truss versus "design" one.

Another cool feature I added last night is the ability to generate 3D models within Google SketchUp.

In order to do this I added SketchUp 3D (.rb) file output for the 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. I think this feature will be particularly interesting to those DIYers who wants to draw up their own model and plans using SketchUp.

The plugin allows for user input in order to specify number of trusses and spacing of the trusses. For example 4 trusses @ 24" o/c would give you:

TRUSS_SKETCHUP2.jpg

The number of updates and new features has become rather lengthy so I created a changelog page to keep track of all this:

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

Earlier this summer the server was getting hammered so I implemented a daily limit however the calculator is still free to use.

Another challenging update was the introduction of point loads under the advanced loading tab. This feature will probably be useful to contractors and homeowners interested in solar panel installations.

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  • 2 weeks later...

Very cool.

Any chance you'll eventually have a calculator for scissor trusses?

It is in my "to do" list but at the moment I'm a bit sidetracked with a SketchUp plugin that allows one to create truss geometry (without the engineering).

After creating the SketchUp output in the Truss Designer I had a number of requests from residential designers who wanted an actual plugin/extension that worked independently from my website and would allow the creation of the geometry within SketchUp.

Here is a link for those interested in beta-testing the new plugin, its still a work in progress but its progressing rather rapidly since geometry is a lot easier to deal with than all of the engineering calcs:

http://design.medeek.com/resources/mede ... lugin.html

Note, that the trial version is currently not limited in any way. At some point when the product is substantial enough to warrant charging for it I will probably introduce some limits to the trial version.

I'm currently working on fine tuning the attic truss option within this plugin.

Here is a 28' attic truss I used on one of my own garage plans:

TRUSS_SKETCHUP10.jpg

I still need to develop the algorithm for raised heels as applied to this truss type and also better logic for span ranges between 16-24' and 30-36'.

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Going off course here for a sec...Do you see any response from the truss industry regarding the recent discovery that metal gussets pop off under condition of fire?

Roof/ceiling assemblies and floors collapse much earlier and firewalls lose integrity. The fire spreads much more quickly, giving firetrucks less time to arrive and folks less time to get out.

I heard NJ was considering outlawing trusses in some types of constructions.

Marc

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Going off course here for a sec...Do you see any response from the truss industry regarding the recent discovery that metal gussets pop off under condition of fire?

Roof/ceiling assemblies and floors collapse much earlier and firewalls lose integrity. The fire spreads much more quickly, giving firetrucks less time to arrive and folks less time to get out.

I heard NJ was considering outlawing trusses in some types of constructions.

Marc

Instead of outlawing trusses, they should inlaw fire suppression systems.

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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.

truss_su10_800.jpg

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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Going off course here for a sec...Do you see any response from the truss industry regarding the recent discovery that metal gussets pop off under condition of fire?

Roof/ceiling assemblies and floors collapse much earlier and firewalls lose integrity. The fire spreads much more quickly, giving firetrucks less time to arrive and folks less time to get out.

I heard NJ was considering outlawing trusses in some types of constructions.

Marc

I have not heard or read anything but that doesn't mean there might not be some movement in this direction. Bowstring trusses have a particularly bad rap when it comes to collapses and fire. Steel is an excellent conductor and has no charring mechanism like wood (specifically large timbers). I'm going to have to do some reading on this, sounds interesting.

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Just out of sheer awe I have to post these two pictures I found at Select Trusses website:

My one worry with commercial buildings constructed using light frame construction is fire resistance. This building wouldn't have a chance if a fire were to occur:

Picture-041.jpg

A quad fink truss (10/9) with a raised heel (slider):

Ag1.jpg

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I've got gable end trusses working for king post trusses:

truss_su12_800.jpg

I haven't made this latest update live just yet as I need to update all of the other truss types to make sure it does not break anything.

The other thing I am changing is the second user prompt box that allows one to enter in the number of trusses. I have now switched to a building length and the logic spaces the trusses based on the this length and the truss on center spacing. Gable end trusses can be switch on or off. Spacing of the gable studs is another user input.

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  • 2 weeks later...

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.

SKETCHUP_TEST1.jpg

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

SKETCHUP_TEST2.jpg

SKETCHUP_TEST3.jpg

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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Do you mean that I could (except for the lateral bracing) use this thing to design an addition to my workshop?

Marc

That's the idea at least. Most people end up paying a designer in the end if they are not familiar with the building codes but I'm amazed at some of the "almost complete" designs that land on my desk these days.

Still a long ways to go to complete this plugin but I keep chipping away at it in my spare time:

Version 1.1.1 - 11.14.2015

- Gable end trusses enabled for all monopitch truss types.

- Added energy/raised heels for monopitch trusses (3 variants: wedge, slider and vertical w/ strut).

Currently there are only two versions of the monopitch truss available (2/2 and 3/3).

The truss set below shows a monopitch truss set with gable ends and a 36" raised heel.

truss_su17_800.jpg

truss_su18_800.jpg

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

truss_su19_800.jpg

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?

One thing worth noting here is that structural outlookers are also enabled but I have not yet coded in the dropped top chord gable end trusses that would match structural outlookers, something for another day. Due to the option of vertically or horizontally oriented outlookers the configuration of a dropped top chord gable end truss can take two configurations. For attic trusses this gets even more complicated at the gable end, hence I haven't even attempted the gable end truss option for attic truss types yet.

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Hah! Don't bother with the dropped chord. We'll just notch it. . .

Every truss document I've ever seen always forbids notching the truss even though I would agree that a typical gable end truss is non-structural and notching of the top chord should be a non-issue.

A few of the contractors I work with will usually order the dropped top chord gable end trusses but when its missed they will usually notch the gable end trusses. They say they've never been called out by the inspector on this.

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Hah! Don't both with the dropped chord. We'll just notch it. . .

Every truss document I've ever seen always forbids notching the truss even though I would agree that a typical gable end truss is non-structural and notching of the top chord should be a non-issue.

A few of the contractors I work with will usually order the dropped top chord gable end trusses but when its missed they will usually notch the gable end trusses. They say they've never been called out by the inspector on this.

From a strictly technical point of view, a gable-end truss isn't a truss at all. It's just some prefab wall framing.

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Version 1.1.6 - 11.26.2015

- Added Fan and Mod Queen common truss types.

- Structural outlookers (vert. & horz.) enabled under advanced roof options for Common (Fan & Mod Queen) truss types.

truss_su24_800.jpg

Four more common truss types still need to be added:

- Double Howe (6/6)

- Mod Fan (8/4)

- Triple Fink (8/7)

- Triple Howe (8/8)

For very large buildings one could also consider:

- Quad Fan (10/5)

- Quad Fink (10/9)

- Quad Howe (10/10)

- Quin Fan (12/6) ...

A quad fink truss (10/9) with a raised heel (slider):

Ag1.jpg

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