I am trying to find eignenvalues to a construction and I am having issues with connecting the slab to the walls of the building.
I import a floor plan from CAD then extract middle lines from the walls to create a karamba model. I am trying to create an automatic process that calculated the eigenvalues on a simple model depending on the floorplan.
However, I am stuck with the slab to wall connectivity. My slab goes crazy when I try to find the eigenvalues or try to analyze the model for gravity loads. I get the following warning:
“1. There are 3 rigid body modes in the system. This means some parts can move freely without causing deformation. Try to use the ‘Eigen Modes’-component and activate the display of local coordinate axes: The first eigen-mode will be the rigid body motion. If this does not help, check whether you have a pinned support directly attached to a hinge. A hinge introduces an extra node which may cause the problem. When analyzing a flat shell structure one has to lock the rotation perpendicular to the plate in at least one node.”
Example of my slab translating when calculating eigenvalues:
I tried adding springs to the slab in many different ways, however I can’t wrap my head around the connectivity. Especially if I go with more floors, the example I uploaded is for 1 floor only, but if I copy the floor plan 3,4 times to get 3 or 4 floors, I have more issues.
Any feedback would be helpful. Thanks!
Rigid slab + shear walls.gh (41.1 KB)