Ring Beam Foundation Design [PDF]

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1 DIMENSION DATA



w1 w2 Tank Shell



Di



d1 Tank  Bottom 



dgw d2



Ring Beam



b1



FOUNDATION SIZE d1 = 0.70 m d2 = 2.00 m b1 = 0.60 m Di = 11.00 m w1 = 0.35 m w2 = 0.25 m LOADING DATA Qe 80.0 t = = Qo = 1200.0 t = Qt = 1100.0 t = Hw 15.0 t = = He = 280.0 t = Mw = 110.0 tm = Me1 = 1230.0 tm = Me2 = 1777.0 tm = 29.0 t = IP = 6.0 t = S = 9.81 m/s2 = g



785 kN (Empty) 11772 kN (Operation) 10791 kN (Test) 148 kN (Wind) 2747 kN (Earthquake) 1080 kNm (Wind) 12067 kNm (Earthquake) 17433 kNm (Earthquake) 285 kNm (Internal Pressure) 59 kNm (Snow) （g : gravity acceleration）



2 DESIGN LOAD 1) WEIGHT OF STRUCTURAL PROPER Soil (γs) = 19.0 KN/m3 Reinforced concrete (γrc) = 24.0 KN/m3 Ground water (γw) = 10.0 KN/m3 GL-0.0m shall be considered on design *) assumed ground water level 1) DESIGN FORCE CALCULATION Ring Beam Weigt (Df) = π/4 [(Di+2 x w1)2-(Di - 2xw2)2] x 2.7 m x γrc = 1355.8 kN = 4442.1 kN Inside Soil Weight (Swi) = π (Di-2 x w2)2/4x 2.7 m x γs Total, Fw = 5797.9 kN 3 STABILITY CHECK 3.1 ALLOWABLE SOIL BEARING PRESSURE Allowable Soil Bearing(qa) = 250.0 KN/m2 For Long Term Allowable Soil Bearing(qa) = 720.0 KN/m2 For Short Term 3.2 SOIL BEARING CHECK (LOCAL CHECK FOR RING BEAM) = 107.51 m2 , Area of tank bottom π/4 (Di+2xw1)2 2 2 π/4 [(Di+2xw1) -(Di - 2xw2) ] = 20.92 m2 , Area of ring beam π/32 [(Di+2xw1)4-(Di - 2xw2)4] = 646.36 m3 , Section Modulus of Ring Beam (Qo-Qe)/At + (Qe + S + Df)/Ar [Me1 + Me2 + Hex(d1 + d2)]/Zr qd + qm qmin = qd - qm 2 2 qm qd qa Remarks qmax (kN/m )qmin (kN/m ) 0.0 1.0(D + Qo) 207.3 207.3 207.3 250.0 qmax OK! 4.2 Hoop Tension Check Design Forces



Di



Ko = h= h



qu1



qu



qu3 qu



Hoop Tension Claculation Load Case : 1.4 (D + Qo) + 1.43E qu1 = 1.4 x Ko x (Qo / At) 76.7 kN/m2 = qu2 = 1.43 x Ko x[(Me1 + Me2) / Zr] 32.6 kN/m2 = qu3 = 1.4 x Ko x γs x h 35.9 kN/m2 = qu4 = 1.4 x Ko x (IP / AT 1.9 kN/m2 = Ring Tension (Tu) Tu = (Di/2) x [h x (qu1 + qu2 + qu4) + 0.50h x qu3] = 1918.0 kN Check for Tension Bar Dtb = 20 mm, Diameter of Tension Bar Ntb = 24 mm, Number of Tension Bar Asreq = Tu / (fy/γm) 4411 mm2 = Amin= 0.0045 x b1 x h 7290 mm2 = Provided As=



7540 mm2 > Asreq and Asmin, OK!



0.5 2.7



, earth coefficient at rest m , height of ring beam