Pile Foundation Calculation For Tank [PDF]

Citation preview

1. Design for Tank TA08 with PMS product Loading Tank



Empty Weight (N)



PMS – TA08



(N) 3,760,480



Operating Weight (N) 66,359,350



Diameter of tank Height of External Beam Breath of External Beam Height of Upstand Beam Breath of Upstand Beam Height of Internal Beam Breath of Internal Beam Thickness of Slab Spacing blw Piles



D= Heb = Web = Hub = Wub = Hib = Wib =



Unit Weight of Concrete



γcon.c =



24 kN/m³



Density of Overburden Sand Perimeter of Tank Area of Tank Area of Block Factors Total Length of Internal Beam



γsand =



17.3 kN/m³ 84.83 m



T= d=



P= Atank = Ablock =



Dead Load (Gk) Empty tank External beam Upstanding beam



27 m 0.6 m 0.25 m 0.6 m 0.4 m 0.6 m 0.25 m 0.25 m 3m



572.63 m² 729 m² 0.79 381.75 m



3760.48 kN 305.40 kN 488.64 kN 1374.31 kN 3435.78 kN 330 kN 5943.89 kN



Internal beams to Caps Top Slab Roof structures Overburden sand



Total dead load Gk



15638.51 kN



Live or Impose Load (Qk) = Hydrostatic (Test) weight Qk



88,012 kN



Total load F= Gk + Qk



=



103,650 kN



Determination of pile capacity from the soil parameter using the static equation Q = Ap (c Nc +γ d Nq ) + (d) (π Ø) (k γd/2) tan ϕ Medium dense sand: viscosity, μ =



30⁰



Angle of internal friction, ϕ = 300 – 350 Bulk density, γ = 15.7 – 17.3 KN/m3 Total unit weight, γt = 18.9 - 20.4 KN/m3 0.6 m Pile diameter = Lateral stress ratio, k = 2 Bearing capacity for deep circular foundation Nq =



30



(from Vesic 1967 curve) Depth of pile =



28 m



Pile capacity Q = Qp + Qs = point resistance + shaft resistance Q = Ap (c Nc +γ d Nq ) + (d) (π Ø) (k γd/2) tan ϕ Note: For cohesionless soil, sand, c = 0 For concrete pile ϕ = ϕcu: for ϕ = 300, ϕcu = 320, adopt ϕcu = 300 Hence, point resistance Qp = Ap (c Nc +γ d Nq ) , c = 0 Qp = Ap γ d Nq 2159.195 KN



Qp = π x 0.62 x 0.25 x 28(18.9 – 9.81) 30 = Tan 30⁰



0.5773503



Qs = (20) x (π x 0.6) x(2) x (20/2 x(18.9 – 9.81) tan 30 = 0



Q=



Qp + Qs



7756.6956196034



=



9915.89 kN Allowable carrying capacity = Pile Capacity / Factor of safety (3.0) 3305.3 kN Say, Q allowable =



3,305



Thus, the allowable or safe working load of the 600 mm diameter pile at 20 m depth is 1800KN.



BS 8004 Claus 7:3:8 sub-section b and g recommend that a factor of safety of 2 – 3 can be applied to ultimate cap



From the soil test report, the safe working load of 600 mm Ø pile is 1200 KN using a factor of safety of 3. This is Hence, safe working load =



1620



Adopt Q allowable =



1620 kN



Nos. of pile required = Total load / safe working load 63.982 64 piles If Qa = nos. of pile required =



3,305 kN is adopted: 31.4 piles