Oil storage tank foundation can be considered as ring wall if the storage tank doesn’t lay on the weak soil. The ring wall foundation dimension (thickness) can be calculated base on below consideration:
1. The I.E. Boberg Equation
T = 24 W / (q.H-80h)
where:
W = weight of shell supported on the ring wall (lb/ft)
H = height of tank shell (ft)
h = height of ring wall (ft)
q = weight of storage product lb/ft3)
T = minimum thickness of ring wall foundation (in)
2. API 650 (Appendix B.4.2.2)
When a concrete ring wall designed, it shall be proportioned so that the allowable soil bearing is not exceeded. The ringwall shall not be less than 300mm (12in) thick.










