STAAD modeling question

[abusementpark]

I posted this over in the STAAD forum, but it does appear to get much activity.

I am modeling a shear wall in STAAD using surface elements. Each floor height of the shear wall is broken into a surface element which is then discretized based on my prescibed fineness.

My question is how do I continuous supports along the bottom surface element of my shear wall that is connected to the foundation. It seems that it will only let me apply support to two nodes that form the bottom corners of surface element. But, I need it put supports along all of the additional nodes it created along the bottom side when the surface element applied my precribed discretization. I would greatly appreciate it if someone could offer me guidance as to the proper way to do this. I hope I have explained the circumstances clearly enough.

Cheers

 

[minorchord2000]

I have the same issue with STAAD. All I do is discretize the panels as close as practicable. It depends on the panel size. I will discretize the panel into no larger than 12 inches each way and sometimes I will go down to 6" in some cases. You will not lose too much accuracy this way when you provide fixed supports at all these nodes.

 

[abusementpark]

So your whole shear wall is made up of 12"x12" panels that you have had to input nodes for manually? It seems to me like that would take forever. Or is it just for the elements along the foundation??

 

[structuresguy]

if you are using surface elements, staad will account for any predefined nodes when it meshes the surface. So I would define all the support points that you want using the copy command (which can do multiple copy at a given spacing). Then define the surface and mesh it. It will grab all your support points in its meshing. I would think that 12" spacing would be more than adequate to provide continuous support.

 

[Qshake]

Also, if you descretize so small and still use frame elements for the remainder of your structure, you're likely to have a numerical instability caused by both large elements and very small elements.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

 

[PanamaStrEng]

I don´t know about STAAD, but RAM Advanse (Also a Bentley product) lets you input if you want the nodes of program generated elements between two restrainsts to have the same restraint or none at all. This is very usefull in the situation described, because you only have to define a very large element for the shear wall and then the program discretizes the mesh and assigns the proper bottom restraints according to your input and the assigned restaints on the large element. I would assume there is something similar in STAAD. If not,I think you could manually discretize the shells in the bottom floor and then the automeshing should consider the nodes already created to maintain continuity in the top floors.