Soil Mechanics & Foundations

Bearing Capacity of Shallow Foundations

Terzaghi's Bearing Capacity

qu = 1/2 γBNγ + c'Nc + qNq - (Strip Foundation)
qu = 0.3 γBNγ + qu + 1.5 c'Nc + qNq - (Circular Foundation)
qu = 0.4 γBNγ + qu + 1.3 c'Nc + qNq - (Square Foundation)
c' - soil cohesion
γ - soil unit weight
If q is not given and df instead is given use this
q = γDf = γ Df {{q()}}
Nc, Nq, Nγ - soil bearing capacity factors solely based on soil friction angle φ
Nc Nq Nγ
γ Width B q
c' FS

Ultimate Bearingn Capacity

qu (Strip Foundation) {{qus()}} psf
qu (Circular Foundation) {{quc()}} psf
qu (Square Foundation) {{qusq()}} psf

Allowable Bearing Capacity

Qall(strip) {{quall()}} psf
Qall (Circular) {{quallc()}} psf
Qall (Square) {{qualls()}} psf