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Modify a floor truss?

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So you can not modify a floor truss like you can a roof truss?

 

I have a truss that needs to step down to a room with a lower floor level & CA drew the truss equal height on both ends.

If I could break the top cord & pull the part down that I need it would work.

I wanted to show this truss in section view so the step down was obvious.

 

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You can unlock the Truss layer and then edit trusses that Chief Architect makes or you can create your own using poly-line solids and poly-line solid holes any shape you like, just takes a little longer. Since I am not a State LIcensed Structural Engineer, I would not do this without a consulting Engineer.

 

DJP

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Thanks David.

Not looking to make trusses you would build just like the roof trusses are not for construction but for general information.

The truss company designs & builds all manufactured truss. That has been my experience.

I'm just looking to supply realistic looking sections. Not actual sections.

The solids tools are too slow for me at my level of experience.

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Open the CAD details managment box and look at the truss detail. You can modify the truss from there. I use this tool to add duct chases in my floor trusses.

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I know this doesn't answer the question, but what is that distance?...can they even make a floor truss that small?

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The floor truss is 14' long.

 

Joey I'll see if I can find that CAD detail

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David the truss layer is unlocked & I can only resize the truss, no other edit.

 

Hamlin, this is the truss CA makes

 

Joe, I can not find where to edit the truss except in a "CAD detail from view" where it becomes CAD lines and is a one way trip, no updates if the plan moves.

I will be better off exporting to ACAD where I can work with lines etc more efficiently.

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Sorry, I should have clarified...

 

What's the height of the floor system on the lower part (where the door is)?  Can the truss company make a floor truss that short?...I was always under the assumption that 14" is about the minimum.  They might recommend that you just handframe that whole section...

 

I understand that Chief might show it, but that doesn't mean it can actually be built.

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Oh I call that the truss height. It is 40" tall and drops to 16" tall.

This type of truss is made like a roof truss with the truss being 1-1/2" wide and not the usual 3-1/2" floor truss width.

I see no problem as only a floor load & no roof load applied to the truss.

 

This is a very complex area where the stair makes it way to the 2nd floor which is 14' above the 1st floor.

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Thinking about it more, you could a 16" truss I frame the floor up to the 40" level but a truss saves the carpenter some work.

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Make sure the layer is unlocked. I modify them all the time from the TRUSS DETAIL in the CAD detail window.

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Joey, Thanks for being persistent. I found that in the layer set within the "Open Truss Detail" has it's own layer set & indeed the layer was locked.

 

How do you create your own objects in that screen?

They are "Framing Members"

I just copied what I needed.

 

 

 

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Alan,

 

As an Architect with good Structural Engineering capabilities I sincerely question that truss since the top chord is not continuous.  I don't see any way to adequately transfer the compression loads in the top chord across the step to the right support.  It would make more sense to build up the floor either with a second set of trusses or joists.

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Joe, Thanks for your input.

I have done broken top cord trusses before but don't have the time to research it. As this is a recommendation to the truss mfg. I will go with it for now.

It may be that they build a 16" truss with the extension on top to get the structural integrity needed. That too will save time for the carpenter.

It will be 2-3 weeks before I get the actual truss profiles & will share the result with you.

Attached is a balcony truss but not near the offset of this proposed truss.

 

Thanks again.

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Looks like the truss can be done.

Don't have the data sheet for it yet only the price quote.

post-2435-0-44575500-1441493266_thumb.png

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Alan,

 

As an Architect with good Structural Engineering capabilities I sincerely question that truss since the top chord is not continuous.  I don't see any way to adequately transfer the compression loads in the top chord across the step to the right support.  It would make more sense to build up the floor either with a second set of trusses or joists.

Joe,

That is a good point, however it can be done. I am not a structural engineer, but I have a fair enough understanding that I like to test them. As long as there is a compression situation you can substitute beefed up webbing along with lvl or larger dimensional lumber that can take stress of compression. Granted the conditions need to be right; the longer the truss the less likely the above can work.

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