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Cantilevered Truss

Cantilevered Truss

Cantilevered Truss

Hi all,
I'm about to design a cantilevered truss ( for the first time) as an openable curved roof with around 30m span, My question is:

- How could this act like a truss since its only one supported; there will be bending moments near the support. Am I right?
- What is the best idea for such a truss?. To be done as a space truss or regular Pratt truss?
- What is the Max allowable Deflection would be like for such a structure?

Guys your Help Would be much much appreciated :))))

RE: Cantilevered Truss

-The moment at the support will break down in axial forces, tension in the top chord and compression in the bottom (under gravity loads), the deeper the truss, the less tension you will have on the top chord connection.

- Space truss would be better as I reckon, but using a regular truss, you should ensure all bracing members are in tension ( slope in the same direction)

- This depends on the usage of the truss and what it is supporting, if it's supporting light metal cladding you can take deflection<= Length of Cantilever/90
if it's carrying glass panels or other brittle finish, you should make sure that the relative deflection of pannel would not result in cracks/smash of the cladding. Design guide 3 is a good reference.

RE: Cantilevered Truss

Thanks Yazan

RE: Cantilevered Truss

With the total lack of any real meaningful design info. you had given, you can’t have imagined that you would get much meaningful discussion. We can’t read your mind, and we can’t see the sketches, plans, concepts, whatever, that you are looking at, from here. A 100' curved truss supporting a moveable roof system needs a bit more detailed description than the above. How is it curved, what’s it supporting, how is it going to be supported, how is what part of the roof moved? These are only a few of the many questions that you have to imagine would be important to any discussion on this matter. This may be your first time designing such a truss, but you better have some engineering imagination and experience as to what info. must be gathered to start to look at possible solutions or variations to the problem, or you probably shouldn’t be doing this problem, without someone right in your office, looking over your shoulder and advising and mentoring as you follow through on this design problem.

RE: Cantilevered Truss

Thanks for your concern;
Regarding the truss it was not cantilever anymore. It didn't work as a 30 m cantilever truss, we had to add supports near the ends and it became simply supported with only 7m overhang.

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