2.2 Bearing capacity for footings on layered soils The use of trial circular arcs can be readily programmed for a computer for two or three layers using su for the layers. It is suggested that the circular arcs be limited to cases where the strength ratio CR=c2/c1 of the top two layers is on the order of 0.6<CR<1.3. where CR is much out of this range there is a large difference in the shear strength of the two layers,Nc is obtained using a method given by Brown and Meyerhof (1969)based on model tests as follows:equation (2.2)~(2.6)2.2 Bearing capacity for footings on layered soils ▪ The use of trial circular arcs can be readily programmed for a computer for two or three layers using su for the layers. ▪ It is suggested that the circular arcs be limited to cases where the strength ratio CR=c2 /c1 of the top two layers is on the order of 0.6<CR≤1.3. ▪ where CR is much out of this range there is a large difference in the shear strength of the two layers, Nc is obtained using a method given by Brown and Meyerhof (1969) based on model tests as follows: equation (2.2)～(2.6)