Applying a Triangular Load Distribution to a Plate Element in RISA 3D

[pootypeters]

I used SAP2000 while in school but my company has a license for RISA. I am creating a mesh of plate elements in RISA to simulate a tie-back retaining wall. The Geotechnical engineer gave me some loading diagrams that are triangular, trapezoidal, and uniform. It seems that I can easily apply the uniform load to the shells elements but I am not sure how to apply a triangular and trapezoidal load. I was thinking of drawing an infinitely flexible member along the nodes of the shell elements and applying the load to that member. However, someone in my office told me that it wouldn't transfer the load to the shells correctly. Please help.

 

[JAE]

When you generate a mesh in RISA there is a generator routine that you can use (look for the small green spider-like tile at the top of the toolbar).
This allows a one-time triangular loading (such as water pressure on the side of a vertical wall).

To use highly flexible members is perhaps valid - I'd want to verify it with a smaller test model first.

You can also manually select bands of elements and step-by-step apply surface loads across each band, one at a time, to achieve a pattern of varying surface loads.

 

[JoshPlumSE]

RISA also has a newer "wall panel" feature. It's something of a "super-element" where you model one rectangular wall and RISA breaks it into a mesh of plate elements based on some geometric restrictions you define. If you use a wall panel, then you can apply trapezoidal or triangular surfaces loads to the wall panel. You might want to take a look at that feature to see if it suits your needs.

 

[pootypeters]

JAE,

Thank you. I did end up going to the generator routine option. I did appear to be very tailored to a wall holding back hydrostatic pressures and I still have difficulties with my trapezoidal loading. I ended up doing exactly what you said and selected bands of elements and applied step-by-step surface loads. It appears to have worked fine but I need to compare it along side another model. The only issue is that if I refine my mesh the loading will become less accurate.

Josh, I haven't found the wall that you are talking about but will look for it as I continue to learn about this program.