Coffer Trusses
Coffer Trusses
(OP)
Starting to take a look at coffer trusses and the first thing that jumps out at me is the peculiar way in which many of these truss types are triangulated.

I'm trying to determine if there is some method to the madness. Unfortunately, I don't have any shop drawings of these truss types and only a very few examples that I have seen online after quite some extensive searching.

I'm trying to determine if there is some method to the madness. Unfortunately, I don't have any shop drawings of these truss types and only a very few examples that I have seen online after quite some extensive searching.
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com





RE: Coffer Trusses
I've found that the terminology varies. The names tray, trey, and coffer seem to be used almost interchangeably.
Some have the vertical ceiling height change, as in your drawing above. Others have a slope going up to the higher ceiling height.
RE: Coffer Trusses
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Coffer Trusses
RE: Coffer Trusses
With the coffer trusses I've noticed that the vertical webs at the transition of the bottom chord typically extend all the way to the top chord. My question with web placement though is at a loss with the webs on each side of the coffer section. Where to place the panel points? and what is driving this?
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Coffer Trusses
In a situation like that where the TC compression is high, adding webs doesn't help much. Adding webs helps when bending forces are a problem. Which isn't the case here.
RE: Coffer Trusses
This is assuming that the coffer span is centered on the truss. A non-centered coffer algorithm could get significantly more interesting and difficult.
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Coffer Trusses
The web triangulation algorithm automatically determines which configuration is appropriate based on the span between panel points. This simplifies the geometry input menu but does take some control from the user.
View model here:
https://3dwarehouse.sketchup.com/model.html?id=a9f...
I think the web placement mostly makes sense but please chime in if there is something that stands out as incorrect.
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com