How can I find the deflection of plates?

Below is a model of a flat concrete slab made of plates. In order to ensure adequate serviceability of the slab, you may need to check the deflection of the slab between columns. However, RISA-3D only reports Member and Joint Deflections. There is no such thing as a “Plate Deflection”.

If you would like to plot the deflection between columns you can use a dummy member. Open the Section Sets spreadsheet and go to the General tab. There you can create a dummy member defined as a rectangular 1” x 1” beam.

Next, draw the dummy member in your model along the line which you would like the deflection plotted. Because this member has such a small area and moment of inertia its stiffness will have a negligible impact on the model’s results. Because it is a Physical Member it will automatically connect to all of the plate corners which it passes (see Plate-Member Interaction)

Link: Plate-Member Interaction

After solving you can look at a detail report for the member to see a detailed deflection diagram.