Construction joints involving shear keys or dowels are common practice for slab-on-grade and mat foundations. Examples of this detail are shown below:
When two different slab elements touch each other in RISAFoundation they are assumed to have a full moment connection, as though they were placed monolithically. However, it is easy to specify a pinned connection along the slab edge, so that shear may be transferred between the two slabs but not moment.
In the example below the shared edge between slabs S1 and S2 is fixed, as indicated by its default blue color:
To specify that this edge should be pinned, use the Modify Edges tool:
Click on the shared slab edge and it will change color, indicating that now only shear can pass between the slabs: