Long Name Ringwall Selfweight Structure Weight excluding Selfweight Live Load Tank Load for Erection Tank Contant Load Tand Hydrotest Load Wind Load Seismic Load Internal Pressure - Operating Internal Pressure - Test Fluid Surge Load
Self Wt Str. Wt Live Load EQ Erection EQ Operation EQ Test Wind Seismic Internal-Op Internal-Test Surge Load
Circumferencial Reinforcement AT = TMAX / fy 0.0020 * b * df AREQ =
Area of Steel for Hoop Tension = Minimum Steel Area as per IS 456 : 2000 = AMIN = Area of Steel Required =
Bar size (db) Sectional area Required No. of Bars Provide 4.7.2-
16 - D12
169.73 3461.45 3461.45
mm2 mm2 mm2
12 113 32
mm mm²
Bars on each face
Vertical Reinforcement Minimum Steel Area as per IS 456 : 2000 = AMIN =
0.0020 * b
1331.325301
Bar size (db) Sectional area Required spacing of bars Provide
D12 @ 165 mm c/c on each face
Page 10
12 113 170
mm²/m mm mm² mm
DESIGN OF RING WALL ANNULAR RAFT Materials Grade of Concrete Grade of Steel
25 N/sq.mm 415 N/sq.mm
Size of Ring Wall Width of Ring Wall 0.65 Central Diameter of Ring Wall, C 3.12 Depth of Ring Wall above FGL 0.60 Depth of Foundation above raft 2.00 Depth of Raft 0.40 Safe bearing capacity 100 Unitweight of Soil 18 Empty Weight of Tank 39 Operating Weight 234 Wind moment 12.5 Seismic Moment 55 Shear at Base Due to Wind 8 Shear at Base Due to Seismic 32 Area of Ring Wall 6.38 Weight of Ring Wall above Raft 398.1 Wieght of soil above Raft ### Total Vertical Load on Raft ### Total Moment due to wind at Raft 30.1 Total Moment due to earthquake at Raft 125.4 Width of Raft 1.4 External Diameter of Raft, D1 4.522 Internal Dia meter of Raft, D2 1.722 Weight of Ring Wall Check for Bearing Pressure Area of Raft 13.73 Section Modulus of Raft 8.89 Max Bearing Pressure under the Raft P/A+M/S 82.8 Increaseing SBC @ 25% 125 Pact<1.25SBC,Hence Safe Design Moments Modified uniform pressure p = p1+0.5p2 74.06 Outer Radius of Raft, a 2.261 Inner Radius of Raft, b 0.861 Central Radius of Raft, c 1.561 As per clause no. 5.1.2 of IS :11089-1984 At radius, r = ### pa^2/16 23.66 b2/a2
0.145
m m m m m kN/sq.m kN kN kN kNm kNm kN kN kN kN kN kNm kNm m m m
sq.m cu.m kN/sq.m kN/sq.m
kN/sq.m m m m
kN
b2/r2
1.000
r2/a2
0.145
c2/a2 Mt Mr At radius, r = pa^2/16
0.477 -82.7 kNm 59.26 kNm ###
b /a 2
2
c /r c/r Mt Mr Maximum Moments for Design Mt Mr Check for Effective Depth Required effective depth, dr 2
2
Provided effective depth, dp
23.66 0.145 0.145 0.690 -61.1 kNm 92.57 kNm 82.72 kNm 92.57 kNm 141 mm 350 mm
Min Area of Steel Spacing of Reinforcement Required Radial Reinforcement Mu/bd2
0.756 N/mm2
Area of steel Required
743.2 mm2
Check Min Steel
420 mm2/ m width 170 mm
Check Min Steel
Min Area of Steel 420 mm / m width Provided diameter of Steel 12 mm Spacing of Reinforcement Required 150 mm Provide 12mm diameter bars @170mm C/C circumferentially Provide 12mm diameter bars @150mm C/C radially 2
