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olyconstruction

How to you fuss with a truss?

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Hi Chiefs, 

 

I am working on this little commercial project, I need to make this sloping roof with standing metal seam over the top. I have made my truss, which you can see if you open elevation 1 of the plan, but I would really like to edit the webbing to make it more realistic. I would like every other member to be horizontal, as in a Howe configuration. Is there a way to change the configurations or the way they display in CA? Am I going to have to build my own (please no)?

 

Let me know what you think, any help is greatly appreciated, 

Thanks :D

AB

N.A.G. PROPOSED 9-7-16.plan

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Also, I was wondering if there is a way to extend the tail of the trusses if I wanted to support downward sloping part of the overhang that way. 

 

And if anyone knows what the minimum truss spacing for a Sloping Flat Truss made of 2x6 with a 20lb. snow load factor, which spans 40', that would be useful information as well  ;)

 

Thanks again

AB

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I don't get too worked up over trusses since we go by the truss manu. engineered drawings for construction.  Our roofplan is more of a guideline, then anything.

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If you want to edit trusses you  unlock the truss envelope poly-line and then you can edit the cords and truss poly line. It is tedious work but can be done. I did such a job for the same reasons as you for a particular project back in Version 9.5, so I know it can be done.

 

DJP

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Truss chord sizes are editable. Not so for web members.

Not quite right - it is all editable under roof truss specification, as well as working with truss profiles in cross section. I see David has answered with how to do it. If you would like further tedium you can move the framing parts of a truss around as well; just be sure to do it at the end of the job, since you can lose your work with any new truss change you may make.

As to spans and centering it is wide open depending upon depth of truss roof decking and materials, communicate those parameters with your truss company or a qualified engineer.

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Thanks for the pointers guys, this is really good info. 

 

Unfortunately when I go to unlock the truss envelope, I receive an error that tells me that the roof and the ceiling planes are too close together so it can not generate the truss for me. Does that mean that the truss is too short to edit? My specifications only call for a 2' tall truss so that may be an issue. I think I will be okay with what I have now, but it is good to know it can be done for future projects.

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AB,

 

Do you mean you want every alternate web horizontal, or do you mean vertical?

 

You have complete control of all the timber pieces that make up the truss, including top and bottom chords as well as the webs.

Get as close as you can by using the truss specifications.

Then, if you need to edit the truss, go to CAD...Cad detail Management... scroll down and select Truss Detail and Open.

Or, you can get there quickly by selecting the truss and then selecting Open Truss Detail on the Edit menu. 

You will see a diagram of the truss.

Unlock the Framing, Roof Trusses layer.

You can now edit the truss any way you like, including extending the tail.

You can even add new framing members.

 

If you want something like the pic below, you can do this in the Roof Truss Specification dbx by adjusting the Maximum Horizontal span settings - no need for any of the above manual editing.

Make both Top Chord and Bottom Chord spacing the same distance and you will get the vertical webbing.

post-106-0-44837100-1473297521_thumb.jpg

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Glenn!

 

That was it, thank you! I totally have the neat spacing now by making the horizontal span equal, and I managed to get a little tail extension going on too!

 

You gave a very good explanation that was easy for me to understand, and for that you deserve commendation. I hereby commend you.

 

post-4666-0-22932500-1473356562_thumb.jpg

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Glenn pretty much hit on the most important points, and good advice about spacing the top and bottom evenly.  I'm usually pretty good about figuring out stuff like this.  That one definitely never occurred to me though.  Kudos Glenn!

 

The one thing I would add to Glenn's list of truss editing tips though would be this...

 

You can get pretty much ANY truss configuration you want manually by using these tools...

-Trim Object(s)

-Extend Object(s)

...Both of which work for truss framing members just like they do with CAD objects

-Join and Lap Ends

-Join and Mitre Ends

post-46-0-59690700-1473394575_thumb.png

 

Anyway, just wanted to throw those additional ideas out there before I check out for the night.

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