Reinforcement modelling issues, two questions

Grasshopper Tekla
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Context/problem:

I am modeling reinforcement for a slightly curved retaining wall in Tekla Structures 2025 using Grasshopper. The concrete geometry is already modeled in Bridge Creator and delivered to the client, so it cannot be modified; my scope is limited to reinforcement modeling. The input geometry is a complex mesh with around 140 faces (see screenshot above), despite the wall following a constant radius.

Two questions:

1.Current workflow in Grasshopper: Mesh from Tekla → road centerline / guideline with known radius → perpendicular frames generated along the centerline → mesh–plane intersections → polyline reduction and simplification → resulting sections used for reinforcement modeling. This works, but it feels brittle and complex given the relatively simple geometry.

Are there better ways to get usable sections from complex bridge meshes? Is it reasonable to create an approximated BREP in Grasshopper (based on on the section lines from mesh/plane intersection and use that as a reference for reinforcement instead?

2. Bent bar defined as arcs – cover issue

I’m modeling bent bars (Q-bars) defined by arcs (start–mid–end).

  • Bars appear locked to the plane.

  • I cannot offset them in the normal direction.

  • Bars end up on the concrete surface instead of ~40 mm inside (cover).

  • Base polyline/arc seems immovable.

Any tips on issue #2?

Thanks in Advamce!

Regards David

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Hi David,

Making some assumptions here since I don’t exactly know how the geometry looks.

  1. I would use the input geometry that they used to create the retaining wall instead of extracting the geometry from Tekla, that way you could get a nice BREP instead of a brep from Tekla which is really a mesh turned back into a brep. From that you can then extract the rebar lines more reliably.
  2. You probably need to provide more information on how you place the bars, are they, groups, rebar sets, single bars? If they are rebar groups how have you placed the range points? Images would be good.

Cheers Oskar

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Hello Oskar, thanks for your reply!

  1. I’ve joined the project late, I believe the concrete geometries are modeled using bridge creator in TS2025, so unfortunately no origin file from rhino.

    So my question might be more general, how do I deal with complex geometries/mesh where I can’t edit the “original geometry”. What I ended up doing was creating sections using mesh / plane, which I then extruded so I had an easier brep to reinforce/select edges on.

  2. I understand, I’ll try to update when I’m back at work.

Thanks

David

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  1. Even if you have used Bridge creator you still would have had to provide some input for the tool. use that input to generate the geometry that you’re after, that will probably save you time in the long run.