Equations for Bearing Capacity Curves

[charliealphabravo]

Does anyone know where I can find empiracal equations for the bearing capacity factor curves in Peck/Hanson/Thornburn? Specifically Ngamma and Nq for shallow foundations.

 

[fattdad]

DM 7.2 has these.

f-d

¡papá gordo ain’t no madre flaca!

 

[jdonville]

The relations Das reports are:

(Vesic 1973, developed by Reissner 1924)
Nq = tan^2(45+phi/2)*e^(pi*tan(phi))

(Vesic 1973, developed by Prandtl 1921)
Nc = (Nq-1)*cot(phi)

(Caquot & Kerisel 1953, Vesic 1973)
Ng = 2*(Nq+1)*tan(phi)

These are the relations used by AASHTO. Other possibilities mentioned in Das are (use the expression for Nq given above in the expressions below):

(Meyerhof 1963)
Ng = (Nq-1)*tan(1.4*phi)

(Hansen 1970)
Nq = 1.5*(Nq-1)*tan(phi)

Hope this helps.

Jeff