graficas

http://web.archive.org/web/20060319154741/http://www.mathcad.com/Library/LibraryContent/rectcols.mcd

The above is an old mathcad file that can be transposed to Prime

"This application calculates the useable strength of tied square or rectangular reinforced concrete columns at the eccentricity of the applied load. The neutral axis location is determined using the Mathcad root function or solve block, and load capacity is computed using stress and strain compatibility, with reinforcing bar stresses calculated for each bar. This approach eliminates the need for approximate methods, tables or interaction diagrams."

Regards

Terry