How to reinforce a raft foundation using SAP2000 ?

There are2 ways to do it, the first one is the most common used which is to assume the passive reinforcement for top& bottom layers, then calculating the moment capacity and put it in the contour range then check that the whole slab are covered, then the additional reinforcement under the columns shall be calculated using section method. The other way depends on designer experience to estimate the proper reinforced section and add to the section properties by using section designer who's allowing add estimated reinforcement and properties, then to choose whether the section to be designed or checked. This method is my preferred method which save time and cost by using most economical sections.