Davit Calc [PDF]

Citation preview

MANWAY DAVIT CALCULATION (Ref. : Pressure Vessels Design Manual, Dennis R. Moss, 1989)



Job No.



:



JN 546-C-TSE-01



Revision



:



AB



Customer



:



CLOUGH INTERNATIONAL



Date



:



18/8/2005



Vessel Description



:



TEST SEPARATOR



Prepare By



:



ASA



A



Design Data Weight of Blind Flange 24"NB 1500 # (incl. 100% misc. weights) Weight of Davit Arm Vertical Impact Factor Horizontal Impact Factor Size of Fillet Weld Allowable Stress of Fillet Weld



B



w1 w2 Cv Ch tc f



: : : : : :



Ys OD r tp Ap Ip Zp rg



: : : : : : : : :



SA-106 Gr. B 35,000 5.563 2.78 0.625 9.696 29.972 10.776 1.760



Sb d



: : :



SA-36 16,534 1.181



L1 L2 L3 L4 R



: : : : :



29.252 24.567 18.898 25.945 11.811



Lbs Lbs



Inch Psi



Properties of Davit Arm Material of Pipe Davit Arm Yield Stress of Davit Arm Material Outside Diameter of Pipe Davit Arm Outside Radius of Pipe Davit Arm Wall Thickness of Pipe Davit Arm Cross Sectional Area Of Pipe Davit Arm Moment Inertia of Pipe Davit Arm Section Modulus of Pipe Davit Arm Radius Gyration of Pipe Davit Arm



C



3,950 200 1.50 0.50 0.375 9,600



Psi Inch Inch Inch Inch2 Inch4 Inch3 Inch



Properties of Eye Bolt Material of Eye Bolt Allowable Stress of Eye Bolt Material Diameter of Eye Bolt



Psi Inch



Inch Inch Inch Inch Inch



D



Stress Coefficients 2 a = tp * R / r b



=



0.625 x 11.811 / 2.782^2



=



6 / (5 + 6a2)



=



6 / (5 + 6 * 0.954^2)



K = = E



a



=



0.954



b



=



0.573



K



=



0.570



1 - [9 / (10 + 12a2)] 1 - (9 / (10 + 12 * 0.954^2))



Davit Arm Calculation 1.



2.



Load applied on davit arm At vertical direction fv = Cv * W1



=



1.5 x 3950



fv



=



5925.000



Lbs



At horizontal direction fh = Ch * W1



=



0.5 x 3950



fh



=



1975.000



Lbs



Bending moment applied on davit arm at top guide or support M1 = fv * L1 + 0.5 * W2 * L1 + fh * L2 =



3. 4. 5. 6. 7. 8.



=



224763.125



Lbs.Inch



Axial load applied on davit arm P = fv + W2 = 5925 + 200



P



=



6125.000



Slenderness ratio Sr = 2.1 * L2 / rg



Sr



=



29.317



Allowable axial stress of pipe davit arm Fa = Stress value (AISC table with Sr)



Fa



=



20010.000



Psi



Allowable bending stress of pipe davit arm Fb = 0.67 * Ys = 0.67 x 35000



Fb



=



23450.000



Psi



Axial stress of pipe davit arm fa = P / A p =



fa



=



631.719



Psi



M2



=



116704.458



Lbs.Inch



fb1



=



20858.477



Psi



Psi



=



2.1 x 24.567 / 1.7598



6125 / 9.696



Lbs



Maximum bending moment in curved davit arm M2 = M1 * (L2 - R) / L2 =



9.



5925 x 29.252 + 0.5 x 200 x 29.252 + 1975 x 24.567 M1



224763.125 x (24.567 - 11.811) / 24.567



Bending stress on pipe davit arm At M1 fb1



=



M1 / Zp



=



[M2 * r / Ip] * [2 / {3K * sqrt(3b)}]



=



[116704.458 x 2.782 / 29.972] x [2 / {3 * 0.57 x sqrt. (3 * 0.573)}] fb2 = 9659.293



=



224763.125 / 10.7756



At M2 fb2



10. Combined stress At M1 = [fa / Fa] + [fb1 / Fb] = At M2



=



0.921



Psi



=



[631.719 / 20010] + [20858.477 / 23450] [fa / Fa] + [fb2 / Fb]



=



[631.719 / 20010] + [9659.293 / 23450]



=



0.443



Psi



11. Judgement a. Since combined stress value at M1 less than 1.0



ADEQUATE



b. Since combined stress value at M2 less than 1.0 F



Eye Bolt Calculation 1. 2. 3. 4. 5. 6.



Area available of eye bolt Arb = p / 4 d2



=



(22/7) / 4 1.181^2



Minimum area required of eye bolt Ar1 = P / Sb = 6125 / 16534



Arb



=



1.096



Inch2



Ar1



=



0.370



Inch2



Judgement Since Arb more than Ar1



ADEQUATE



Length of fillet weld on eye bolt Lw = 2 * p * d = 2 x (22/7) x 1.1811



Lw



=



7.424



Inch



Minimum required fillet weld leg size tc2 = P / (Lw * f) = 6125 / (7.424 x 9600)



tc2



=



0.086



Inch



Inch2



Judgement Since tc2 less than tc



G



ADEQUATE



ADEQUATE



Welding Size on Plate and Pipe 1. 2. 3. 4. 5.



Section modulus of weld lines Sw = L32 / 3 =



18.898^2 / 3



Sw



=



119.045



Bending moment Mb = P * L4



6125 x 25.945



Mb



=



158913.125



Lbs.Inch



Bending force applied on fillet weld Wb = Mb / Sw = 158913.125 / 119.045



Wb



=



1334.902



Lbs/Inch



Average vertical shear force applied on fillet weld Ws = P / 2 L3 = 6125 / 2 x 18.898



Ws



=



162.054



Lbs/Inch



Rw



=



1344.702



Lbs/Inch



tc1



=



0.140



Resultante force applied on fillet weld Rw = Sqrt (Wb2 + Ws2) =



6. 7.



=



Sqrt (1334.902^2 + 162.054^2)



Minimum required fillet weld leg size tc1 = Rw / f = 1344.702 / 9600 Judgement Since tc1 less than tc



ADEQUATE



Inch



ADEQUATE ADEQUATE



743



29.252



624



24.567



480



18.898



659



25.945



300



11.811