Author Topic: Truss Calculators  (Read 369595 times)

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Offline Medeek

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Re: Truss Calculators
« Reply #150 on: November 08, 2015, 07:14:59 AM »
Version 1.1.0 - 11.08.2015
Added advanced roof options for Common, Scissor and Attic truss types.
Sheathing option enabled under advanced roof options.
Rake Board option enabled under advanced roof options.
Fascia (Flush, Dropped, Beveled) option enabled under advanced roof options.




2x6 fascia and rake boards with gable end trusses.  I would show the sheathing but it covers up the trusses and then there is really nothing to look at.
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer

Offline Medeek

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Re: Truss Calculators
« Reply #151 on: November 08, 2015, 04:17:39 PM »
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.
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer


Offline Medeek

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Re: Truss Calculators
« Reply #152 on: November 08, 2015, 04:19:01 PM »




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.
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer

Offline Don_P

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Re: Truss Calculators
« Reply #153 on: November 08, 2015, 04:59:15 PM »
Very cool drawings, I was in their catalog today looking at truss girder connectors for post frame girders and wondered if their hardware was in skp. To your point though, usually a sketch like that is an evening or two for me, you've kicked it up a couple of notches  [cool].

Offline Medeek

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Re: Truss Calculators
« Reply #154 on: November 08, 2015, 06:10:10 PM »
I should be working on my regular work but SketchUp has an addictive hold on me at the moment.  Trying to do a bit more complex roof line below.  Immediately some things that pop out are the inherent complexities that occur when roof lines meet.  The question is how to setup the plugin to automatically handle these situations, this will not be easy.  I was able to easily trim and delete unnecessary rake and fascia boards as required.  The trusses themselves need to be more dynamic so that one can adjust the overhang to zero as required.  It is easy to select a number of component instances and make them unique and then adjust as required.  In the second image I've copied an instance of the queen post truss to create a girder analog. 

The other thing that needs some attention is the ability to easily create a valley set that frames over the larger roof line.  I've got some ideas on this one, its going to take some interesting math but its not impossible.





Also notice how I have used a howe, fink and queen post truss to demonstrate the use of all three truss types. 

The other interesting point is that when you specify the fascia boards it is quickly apparent whether or not the heel heights match up and everything is correct. 
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer


Offline Don_P

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Re: Truss Calculators
« Reply #155 on: November 08, 2015, 06:30:58 PM »
Cool, the old adage, draw the gutter line. This can somehow be used with stickframing to get birdsmouth height correct on a cut up roof to that same end.

Offline Medeek

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Re: Truss Calculators
« Reply #156 on: November 10, 2015, 02:32:47 AM »
Version 1.1.0 - 11.10.2015
Gable end trusses enabled for the Fink truss type and all raised heel variants.

I may need to adjust the vertical studs slightly for the raised heel with slider. I haven't yet determined the best way to frame that situation out.

Lots of cleaning up needs to be done, tedious stuff but necessary.

Enable gable end option for all other truss types.
Enable raised heel option for all other truss types.
Verify that metric input is functioning correctly for all options and truss types.
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer

Offline Medeek

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Re: Truss Calculators
« Reply #157 on: November 10, 2015, 08:22:29 AM »
On a slightly different note I'm thinking about creating a plugin for wall framing and other misc. framing related items for residential construction:

- Walls
- Floors
- Stairs
- Dormers
- Foundations
- Posts and Beams
- Square and Round Footings

Any great ideas on names.  Its going to be something like Medeek Framer or Medeek Construction but I just don't want to make it too narrow in scope since I will probably wrap a number of things into it.

I like the housebuilder extension but I think a lot more can be done based on this initial concept.

Items I would like to see are more flexibility in defining openings, double trimmers, double king studs, double window sill plates. 

I would also like to have the ability to create portal frames per the IRC standard.  As well as classify certain wall segments as shearwalls and automatically insert the holdown components (Simpson HDU series) into the wall.

For structural engineers I've got some ideas for a plugin called Medeek Structure which will do lateral load analysis for wind and seismic similar to the Woodworks Shearwall software that I currently use on my local engineering projects.
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer

Offline Medeek

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Re: Truss Calculators
« Reply #158 on: November 11, 2015, 07:20:05 PM »
Any roof can get very complicated with intersecting roof lines whether it is framed out with trusses or more traditional rafters and beams.

If I incorporate traditional framing I would like for the user to be able to indicate the perimeter of the ext. walls and for the logic to be smart enough to handle any possible configuration.  Consider the custom home with guest house below:



Just to determine the proper placement of the ridge and valley lines requires some serious algorithms.  The technique I used to do it manually simply involves drawing isolines moving a fixed increment in from the ext. wall line.  These are really no different than contour lines on a topographic map.  The vertexes created by the intersection of these lines indicate the location of hip rafter, flying hip rafters and valley rafters.  When the isolines merge into one line then you have a ridge board.
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer


Offline knopfarrow

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Re: Truss Calculators
« Reply #159 on: November 11, 2015, 09:21:15 PM »
Quote
Any great ideas on names.

How about "Medeek Build." Short. Simple. And catch all but indicative.
"One is not a pattern. Two is not a trend." -me

Offline Don_P

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Re: Truss Calculators
« Reply #160 on: November 12, 2015, 03:48:08 AM »
What happens when the roofs have different pitches from each other? If it starts thinking at the building line will the gutter line remain level?

Offline Medeek

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Re: Truss Calculators
« Reply #161 on: November 12, 2015, 08:06:13 AM »
What happens when the roofs have different pitches from each other? If it starts thinking at the building line will the gutter line remain level?

That does further complicate things.  An interesting implementation of a straight line skeleton algorithm is at this link:

Nathaniel P. Wilkerson, P.E.
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Offline Don_P

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Re: Truss Calculators
« Reply #162 on: November 12, 2015, 06:29:49 PM »
I'm not sure how to ask it, can the program "think" from a level gutter line and then work back from there. Hips and valleys drift out of corners at the building line, correctly, to maintain level and consistent overhang depth with dissimilar pitches. Then heel depth can help tune it in.

Offline Medeek

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Re: Truss Calculators
« Reply #163 on: November 14, 2015, 06:37:42 PM »
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.

Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer


Offline Medeek

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Re: Truss Calculators
« Reply #164 on: November 15, 2015, 12:24:40 AM »
I've also added advanced options for monopitch trusses (sheathing, rake and fascia).

Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer

Offline garyc

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Re: Truss Calculators
« Reply #165 on: November 15, 2015, 11:57:14 AM »
This is a building that I built in 2012 using mono trusses with a 3' heal. These trusses are 64' long with a 1"-12"pitch. I built this building for my business.

 

If it wasn't for bad luck . I would 't have any luck at all.

Offline Medeek

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Re: Truss Calculators
« Reply #166 on: November 15, 2015, 12:10:18 PM »
That is a crazy span.  The webs in this truss are very interesting, a Warren type truss mixed with vertical webs (modified Warren).  I am curious as to how they arrived at this design.  You can tell these trusses will be under a signficant load, look at the splice plate and additional blocking on the bottom chord.  The scale of these trusses really comes to light with the construction worker in the photo (second photo). Thank-you for sharing this.
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer

Offline Medeek

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Re: Truss Calculators
« Reply #167 on: November 16, 2015, 07:43:05 AM »
Version 1.1.2 - 11.16.2015
Metric input enabled for monopitch truss types.
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer

Offline azgreg

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Re: Truss Calculators
« Reply #168 on: November 16, 2015, 09:58:41 AM »
Great work. This should be a sticky.

Offline Medeek

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Re: Truss Calculators
« Reply #169 on: November 21, 2015, 12:46:40 AM »
Given the slopes of the dual pitch truss and the span calculate the distance between the left bearing and the peak:




However, you might notice that we are assuming the buttcut and top chord depth is equivalent for both sides.  If the slopes are different then this will mean that the heel heights will be different.  Should the heel heights be the same?
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer


Offline Don_P

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Re: Truss Calculators
« Reply #170 on: November 21, 2015, 03:53:50 AM »
The overhangs should be at the same height, this will determine the HAP

Offline Medeek

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Re: Truss Calculators
« Reply #171 on: November 21, 2015, 11:31:13 AM »
The overhangs should be at the same height, this will determine the HAP

You're right the fascia is the key.
Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer

Offline Medeek

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Re: Truss Calculators
« Reply #172 on: November 21, 2015, 09:57:05 PM »
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?

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.

The hot items on the todo list right now are:

- Tail Bearing Trusses
- Gambrel Attic Trusses
- Dual Pitch Trusses
- Rafter Roof (Gable and Hip)
- Valley Truss Set
- Hip Truss Sets

If you feel like something should take precedence over these items please advise.
« Last Edit: November 21, 2015, 10:30:14 PM by Medeek »
Nathaniel P. Wilkerson, P.E.
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Offline Medeek

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Re: Truss Calculators
« Reply #173 on: November 22, 2015, 01:04:46 AM »
Version 1.1.3 - 11.21.2015
Outlookers enabled under advanced roof options for Common, Scissor and Attic truss types.
Gable end trusses enabled for (2/2, 4/4) scissor truss types.


Nathaniel P. Wilkerson, P.E.
Designer, Programmer and Engineer

Offline Don_P

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Re: Truss Calculators
« Reply #174 on: November 22, 2015, 04:58:56 AM »
I usually measure lookouts from the bottom. I'll decide where the bottom of the sheathing will land and then run the lookouts on 2' centers from there up, thus blocking the edges.
In a visual radio button option type menu you would click on overhang type then it would figure lookout layout from that. On structural lookouts I'll typically block over the top chord if they are standing.  I don't frame what you drew ever, the quick and dirty option is to notch the undropped gable truss 1.5" deep and lay lookouts flatways from the 1'st common truss, over the notched gable and out to the fly rafter. However, doing the math, the hog trough you drew never works structurally, flatways lookouts only work on shorter gable overhangs or lighter loads. They really need to rotate upright pretty quickly... this could be calculated in the background and the drawing would rotate them up right when the load/span requires the change. Flatways is nice because layout for sheathing breaks isn't as critical, plenty of nailing on the flat face of a 2x. I'll buy wiggle room by using flatways 2x6's sometimes.

As a personal rant, if I'm cutting, I hand up #1 or SS lookout stock, it is an opportunity to cut out defects. Someone is climbing that ladder during construction, leaning over the cantilever and nailing on the fly. The wind and snow is working it for the rest of time.   So often a helper will mindlessly chop lengths without looking at the wood. I was handed a fistful of wicked knots yesterday... real world strength, zero. Look at what you're cutting folks.
« Last Edit: November 22, 2015, 05:16:52 AM by Don_P »