Staad Supports 1

[Alex786]

Hi ,
I am designing a Space frame canopy , the support conditions are in the attached file .
Kindly advice whether the support conditions should be Release Fx Fy Fz Mx My Mz or Should we define springs , if yes how to define them .
Thanks Guys !

 

[SethGuthrie]

If you pin or fix the base nodes, then of course the deflection there will be zero. If you apply a spring support at the base, then deflections are possible and I suppose you could establish a required stiffness to meet your deflection limitations. Spring supports are defined in the GUI in the same location as the other supports, you can even created inclined springs for the skewed frame if necessary.

 

[Alex786]

Would you tell me how to define spring supports in this case , because it is the first time i am defining springs in staad ,
Thanks!

 

[SethGuthrie]

Take a look at the program help contents for details.
If you are using the graphical user interface, then refer to 2.2.3.3 General | Support Page
If you are using an input file, then refer to 5.27.1 Global Support Specification

 

[dozer]

Why don't you model the columns also? That way you don't have to figure out spring constants.

 

[SteelPE]

You need to model the structure as it is going to be built in the field. As stated above fixing a support will set deflection of that condition to 0. FX FY and FZ are generally translations to their respective axis and MX MY and MZ are rotations to their respective axis. Fixing or releasing these is very easy. Defining a spring is more difficult because you need to know the stuffiness of the spring to apply in the program.... and you need to make sure you and the program are using the same units. For example, STAAD often defines a spring using the units Ft-Kips/Degree. That means you need to know how many foot-kips it takes to rotate the support 1 degree.