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Engineered Trusses

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Question:  I have a truss company with structures software that will design and stamp my trusses. vaults, perhaps trays. What do you guys do get the truss drawing from them and then update your models? Is there something I can do or get from the truss company to make it simpler? 

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Generally I create the model and layout the trusses and then send i to the truss co.

They do there thing and then i review for conflicts or issues.

I may may make some revisions after that but not many.

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I agree with Rob: review the truss drawings to make sure they conform to your architectural intent. If they don't, mark them up and send them back. If there are still issues (like whether a truss can be built to accomplish what you want), then get on the phone with the truss designer and hammer out a solution. Then you can update your model. So, ideally, the trusses should conform to your model, not the other way around. That's the simplest method.

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Truss manufacturer is no different than any other business, they want to sell you all they can. I ALWAYS do my own truss design and let the truss engineer do his job too. I have had jobs with over 100 individual truss prints.

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Ok, I'll design the trusses and let them mark them up. I already visited them with my stick rafter CA model and learned they have a max height of 12' due to jig/tools I exceed so they have to make a "piggback" scissor truss to get to my ridge, or mate the upper chord of the bottom truss to another lower chord of the top truss in a two piece design that has plates to attach them. So you guys model that level of detail? They play with the lower chord pitch to stay in that 12' mine ended up 3/12 lower chord with a 8/12 upper chord. Then there is span deflection just a guess until they let me know otherwise. 

 

I'm more of metal truss designer. I use similar FEM software NASTRAN or PATRAN and I'm not use to jig constraints. 

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I don't go into that detail and frankly don't know and designers or architects around her that do.

 

Are you meaning a 12" max heal height on the truss?

Seems odd- we do raised heel trusses all the time with 2-3-4- foot heels depending on need and plane.

 

And when it comes to scissor trusses we can usually get 2 less pitch on eh lid than we get on the roof.

IE. your 8/12 roof would get a 6/12 ceiling max.

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I agree with Rob: review the truss drawings to make sure they conform to your architectural intent. If they don't, mark them up and send them back. If there are still issues (like whether a truss can be built to accomplish what you want), then get on the phone with the truss designer and hammer out a solution. Then you can update your model. So, ideally, the trusses should conform to your model, not the other way around. That's the simplest method.

And I agree with Rob & Robert,  I draw trusses for every project I do.  Helps me find problems in my design.  If I can't get a truss to form or I see framing sticking out of a roof then it's time to investigate.

 

Typically, if I have a question of whether or not a truss can carry a load I will talk to designers or they will call if they have questions or trouble; otherwise I move on to the next project. 

 

I do try to detail as much as possible, but I stop at piggy back trusses or caps.  Truss mfg. around here have options to pilot car and buy wide load permits or not, hence I allow them to make their own decisions - there can be more than one way to truss a house and I don't get hung up on that as long as nothing changes in the elevations.

 

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Here is a PIC of a quick and dirty they did for me showing the piggyback, no cap yet. I have a 57' span, so I end up with 3/12 lower chord based on the 12-0-0 max height. It will be interesting to see if I get the same dimensions and truss out of CA or I guess you guys are saying don't sweat it. So I won't sweat the modeling the piggyback....The intent of modeling is to make sure the basic geometry works, let them do the FEM and final designs. They other thing their model can do mine cannot is if I start running into deflection issues they can locate an interior load being wall/footing. I guess that is what the mark-up is for.  

 

I want a 11-0-0 energy heal they did not model since I did know what insulation value I wanted at the time. 

 

The vault is in my kitchen/living room. I'm thinking of vaulting the Master since they brought to my attention it is better to box down vs. recess into the truss a tray ceiling. That cost is a little higher than a vault due too less labor in the drywalling. I have 10' walls so if I box down 2' that leaves 8' still. 

 

PS: I don't like the tint in Windows 10 photo viewer and have not figured out how to change it yet. 

 

post-5962-0-89339800-1440853411_thumb.jpg

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Why not just have the truss co. under frame the coffer off the bottom chords?

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Why not just have the truss co. under frame the coffer off the bottom chords?

 Under-cut the lower chord: Because it reduces the cross-sectional area loads can take, P/A. If you are fighting deflection for example it makes it worse. I have one at -1.38" getting there. The lower chord usually takes the bulk of the load, depending. 

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Unless I am missing something, why don't you just model the truss in another app that will allow you to create an exact model of the trusses and bring it into Chief as a Symbol?

 

I always put a note on the plans that the truss depictions are a graphical representation only, and that the truss drawings will be supplied by the truss manufacturer.  Code requirement anyway.

 

There is another thing about using a symbol rather than Chief's trusses and that is if you want to produce a U3D file Chief's trusses do not hide surfaces correctly where the outside source method does.  This actually saves time in that any camera views you create for CDs are now correct.

 

I still try to get by with Chief's trusses as much as I can, but if the need arrises I don't hesitate to create a symbol.  Quite often I wish I had rather than deal with Chief's issues.

 

The general process is to enter the coordinates of the joint connections and draw lines and offset lines so I can use a polyline to create each member.  I have found that if you keep evey member on the same layer the member intersection will not display correctly in Chief.  Just need to have a way to create unique material definitions and all is well.

 

BTW check out the U3D file I posted in the "What Chief CAN" do thread Joey started in the Chatroom forum to see what I am refering to about Chief's trusses not displaying correctly in when exported.

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No - not cut the truss chord- can't ever do that.

Just bring a flat bottom member out 2' or whatever the flat of the coffer is desired to be.- The attachment is with a press plate as in any flat bottom chord truss.

Then run a vertical leg up to the scissor.

Then 1 more flat chord across to the other side and the mirror of the first side.

Block in between the trusses at the coffer line and a bit of corner backing- Done deal

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No - not cut the truss chord- can't ever do that.

Just bring a flat bottom member out 2' or whatever the flat of the coffer is desired to be.- The attachment is with a press plate as in any flat bottom chord truss.

Then run a vertical leg up to the scissor.

Then 1 more flat chord across to the other side and the mirror of the first side.

Block in between the trusses at the coffer line and a bit of corner backing- Done deal

 

The truss company I talked to (my first BTW this is new to me) said they cut the lower chord all the time to get more head height but do not recommend it. It may be fine in certain load cases. I did not catch what you meant my bad, right, of course have the truss company do the coffer to avoid my frammers cost of stick building them. It is the dry walling I was saying will cost a little more compared to a vault. I was going to model a truss on CATIA but I just found out it is not not compatible with W10 just like my BOSE speaker blue tooth. I'm mad at myself for not waiting for the bugs to be worked out like drivers, etc....

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Unless I am missing something, why don't you just model the truss in another app that will allow you to create an exact model of the trusses and bring it into Chief as a Symbol?

 

I always put a note on the plans that the truss depictions are a graphical representation only, and that the truss drawings will be supplied by the truss manufacturer.  Code requirement anyway.

 

There is another thing about using a symbol rather than Chief's trusses and that is if you want to produce a U3D file Chief's trusses do not hide surfaces correctly where the outside source method does.  This actually saves time in that any camera views you create for CDs are now correct.

 

I still try to get by with Chief's trusses as much as I can, but if the need arrises I don't hesitate to create a symbol.  Quite often I wish I had rather than deal with Chief's issues.

 

The general process is to enter the coordinates of the joint connections and draw lines and offset lines so I can use a polyline to create each member.  I have found that if you keep evey member on the same layer the member intersection will not display correctly in Chief.  Just need to have a way to create unique material definitions and all is well.

 

BTW check out the U3D file I posted in the "What Chief CAN" do thread Joey started in the Chatroom forum to see what I am refering to about Chief's trusses not displaying correctly in when exported.

 

Being new to CA I watched a quick video on symbols. In the short time I been using CA it seems like it can be a PITA getting roofs to work. Banging out the truss design in another program I am faster at then importing a symbol looks promising. I guess I can apply and texture and color I want? How would I clad(sheath, shingles, etc) over symbols?  I guess everything above and below the symbols will then be done manually? Most of what I have done thus far in auto so I dunno yet. 

 

http://video.chiefarchitect.com/?search=symbol

 

The general process is to enter the coordinates of the joint connections and draw lines and offset lines so I can use a polyline to create each member.  I have found that if you keep every member on the same layer the member intersection will not display correctly in Chief.  Just need to have a way to create unique material definitions and all is well.

 

 

You lost me a little here. Are you talking about creating polylines & solids in the other program> Then import each truss symbol on a different layer so CA displays correctly? How do you create the material defs? 

 

BTW check out the U3D file I posted in the "What Chief CAN" do thread Joey started in the Chatroom forum to see what I am refering to about Chief's trusses not displaying correctly in when exported.

 

 

https://chieftalk.chiefarchitect.com/index.php?/topic/6232-what-chief-can-do/page-4#entry56989

 

I see! Joey's PDF looks pretty sweet compared to CA. I guess the problem would be not being able to apply CA unique material definitions to symbol components...That would have to be done in the other program before importing a symbol? See attached. I have no experience with exporting UD3 files so sorry if I am not making sense. 

post-5962-0-76020100-1440945586_thumb.jpg

post-5962-0-29168400-1440945602_thumb.jpg

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You create the layer definitions in the other app and assign the materials in Chief either on import or you can edit the material definitions any time later.

 

You can create the trusses as either 3D surfaces or 3D solids in the other app and Chief will import either one just fine from my experience.

 

I am starting to think that I may need to create some sort of readme file to go along with the U3D file so folks know how to use it.  In general, being a U3D or full 3D file in the PDF format it can be viewed using adobe's free viewer that you would use to view ordinary text documents.  The material definitions for the U3D file have to be set up differently than is req'd for display in other programs such as Chief.  I am more focused on getting the content created and converted for on site use at this time.

 

To use the U3D file check or uncheck the layers you want to either show or hide and then use the cursor by hovering it over the model and using the icons on the top to control the mode of camera movement.  It also has the ability to section the model and many other capabilites as well.  My personal preference for the render mode is shaded illustration found on the contol bar at the top under the blue cube with a small green rectangle.  I also like the cubic lighting mode found under the lampstand icon.

 

It seems to me that this type of design deliverable that uses a free viewer and does not require any previous CAD experience holds a lot of potential for construction applications.  The problem seems to be all of the marketing hype that has led people to believe that they have to buy that expensive BIM program in order to use these technologies.  Nothing could be further from the truth.

 

There are quite a few work arounds, or hoops to jump through in order to create a file of this type, but so long as the content is created accurately the converion process, other than layer issues, is working fairly well for me now.

 

Did you check out how Chief's trusses do not show correctly in 3D in the U3D file?

 

Note:  the Navigation icons do not display until the cursor is over the model area.  Great app, but this part is not very intuitive to say the least.

 

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