Girder bridges

[rozsasarpi]

A note on this: I could already make use in one of my projects a girder model like this:

• 2D model;
• a single girder is modeled;
• the cross-sectional properties (area, second moment of inertia, or entire cross section definitions) are provided by the user;
• spans can be adjusted;
• springs can added at any node (not just at supports): translational and rotational;
• loads: point forces and point moments (no temperature, creep, shrinkage, etc.)

Something like this:

I may give the implementation of try later.

[jerbaroo]

I think the most simple way of adding this to the API is to introduce a new bridge type e.g. Bridge2DGirder, to complement the Bridge3DSlab which currently exists (named Bridge). I don't think having a single Bridge type makes sense, because then we don't know until the bridge is used to run 2D/3D simulations if all/some of the attributes are needed.

springs can added at any node (not just at supports)

What would these additional springs represent in "the real world"?

I may give the implementation of try later.

I suggest I do some initial work on it, just to get a minimal example running, and the other features you listed you could then add. The example you presented seems quite like what I did at the very beginning with OpenSees.

[rozsasarpi]

I think the most simple way of adding this to the API is to introduce a new bridge type e.g. Bridge2DGirder, to complement the Bridge3DSlab which currently exists (named Bridge). I don't think having a single Bridge type makes sense, because then we don't know until the bridge is used to run 2D/3D simulations if all/some of the attributes are needed.

I agree.

What would these additional springs represent in "the real world"?

For example they can represent the following structural elements:

• the other girders and the bridge deck that are not modeled for simplicity but have an impact on the response of the single girder;
• cross-beams, bracings, and diaphragms between girders.

In both cases the springs are representing the stiffness contribution of the not modeled structural elements. It is often difficult to set the corresponding spring stiffnesses because that would require a more detailed model but with measurement data they can be estimated.

Check this for further images about these structural elements.

I suggest I do some initial work on it, just to get a minimal example running, and the other features you listed you could then add. The example you presented seems quite like what I did at the very beginning with OpenSees.

That sounds great, thanks!

[jerbaroo]

Thinking about this, I think it's best to finish #188 first. Rather than working on two large PRs at once.