I am designing a mat foundation supporting a steel structure. I am applying the column loads as NODAL LOAD. I do not think this is the right approach because I have a base plate that distributes the load over the area of the base plate. How to model this ?
There are a couple of things you can do.
1.Instead of applying the load as a concentrated point load, try applying the load as a pressure loading on the plates.
2.You may define dummy members ( having high E and zero density ) between the point of application of the concentrated load and the neighboring plate nodes which would help in distributing the load over a wider area.