Composite curved bridge in karamba

I’m Andrea, new user of karamba.
I’ve modeled a bridge made of concrete deck and steel box girder in gh. now I’m doing the structural analysis in karamba. I draw the steel box as a shell and the diagonal reinforcement as line to beam to create the element to insert in the assemble model, but I’m having some troubles in assign a assign to the concrete deck a kind of element. I don’t know if it’s good to create a separate mesh to shell for the concrete deck and connect it to the other steel box mesh to shell. how can they be connected and work together?

Thank you

Hello @Andrea7,
if one wants to combine beams and shells one needs to subdivide the beams into small pieces and make sur that their endpoints coincide with vertices of the mesh (using e.g. the ‘IPts’ input of the K3D MeshBreps component).
For reinforcement design the easier option is to use a ShellRC cross section and then apply the ‘Optimize Reinforcement’-component (see here: 3.6.11: Optimize Reinforcement 🔷 - Karamba3D 2.2.0).
– Clemens

Thank you Clemens,
I’m still having having issues with the mesh to shell, it’s giving a weird clouds of points and it makes the beams not going “straight” but following a zigzig path (this is because I used the component Closest points, taking the points from the cloud given by the mesh to shell). Where as in the cloud of points given to the previous component Mesh Breps, the cloud of points results correct, following the edges of the brep.
I ve already tried to increase the mesh resolution, but it doesn’t change.

I already tried to not use the component closest point to create the polylines, but when I analyze the model is giving me the classic error:
“1. There are 4 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.”
But there are no duplicates line or duplicates points in the model.

I attach you the file gh and rhino.
Str analysis.3dm (135.4 KB)
structural (124.2 KB)

thank you again for your support