L1=2000

L2

=1

00

0

R=750

2000 M2

M1

Pipe Material : SA 106 GR. BMinimum Yield Stress, Sy = 241.32 MPaAllowable Bending Stress, Fb = 144.79 MPaPipe = 6" Sch 120, OD = 168.3 mm

18.26

131.78 mmr = Radius of Gyration = 53.4 mm

A = Cross sectional Area = 8607a = Outside radius of pipe = 84.2 mmL1 = 2000 mmL2 = 1000 mmL3 = 1000 mmL4 = 290 mmR = 750 mmB (Guide plate width) = 210 mm

VESSEL DAVIT DESIGN (BASED ON PRESSURE VESSEL DESIGN MANUAL BY DENNIS R MOSS)

tp = thickness of pipe =

di = ID of Pipe =

mm2

I = Moment of Inertia of Pipe = 24579160

Z= Section modulous of Pipe = 292087WL= Maximum rated capacity = 500 KgsW1=Weight of boom & brace = 125 KgsWD = Total Weight of davit = 350 Kgs

1.8

0.5

900 Kgs

250 Kgs

Axial load on davit mast, P:

2150 Kgs21092 N

Bending Moment in davit mast, M1 (TYPE 1):

3975000 Kgf - mm38994750 N-mm

For Type B Davit:Axial Stress:

2.45 MPaBending Moment, M2:M2 = M1 (L2-R)/L2 9748688 N-mm

Coefficients:

1.93

0.22

0.84

133.50 MPa< Fb, Hence Safe

32.86 MPa<Fb, Hence Safe

39

132.86 MPa(From Table C-36 of Manual of Steel Construction by AISC)

0.94<1.0, Hence Safe

mm4

mm3

Cv =

Ch =

fv = Cv WL =

fh = Ch WL =

P =2fv + WD =

Type 1: M1 =2fvL1+0.5W1L1+fhL2 =

fa = P/A =

a = tp R/a2 =

b = 6 / (5+6a2) =

K = 1 - 9 / (10+12a2) =

Bending Stress, fb :

Sy, Yield Stress for SA 106 Gr. B is 241.32 MPa.

Fb, Allowable bending Stress (0.6 x Sy) is 144.8 MPa.

At M1, fb = M1/Z

At M2, fb = (M2 a/I)*(2 / 3K Sqrt(3b))

Combined Stress:

Slenderness Ratio = 2.1*L2/r =

Fa = Allowable Axial Stress =

fa/Fa + fb/Fb =

FINDING EQUIVALENT RADIAL LOAD, FreRadial Force At Guide & Support, Fr = M1/L3

= 38994.8 N

11308478 N-mmLongitudinal moment at guide, Mx=P*L4 6116535 N-mm

N/mm

Equivalent Radial Load, Fre = w*B/2 N

w (N/mm) Fre (N)0 185.7 19497

20 700.7 7357540 1131.2 11877850 1298.0 13628760 1425.3 14965565 1472.9 15465470 1509.3 15847675 1534.2 16109180 1547.4 16248190 1538.6 161550

Loads for Local Stress Analysis:At Guide: Radial Load, Fre = 162481 N

At Support: Radial Load, Fre = 162481 N Longitudinal Moment, Mx = 6116535 N-mm

Fr is max when davit rotation f is at 0o

Circumferential moment at guide and support, Mf = Fr * L4

Mf is max when davit rotation f is at 90o,

Equivalent Unit load, w = (Fr*Cosf / B) + (6*Fr*L4*Sinf / B2 )

f (o)

Table C-36 (AISC)

kl/r Fa (ksi) Fa (Mpa) 1021 21.56 148.65 88.597672 21.52 148.383 21.48 148.104 21.44 147.825 21.39 147.486 21.35 147.207 21.3 146.868 21.25 146.519 21.21 146.24

10 21.16 145.8911 21.1 145.4812 21.05 145.1313 21 144.7914 20.95 144.4515 20.89 144.0316 20.83 143.6217 20.78 143.2718 20.72 142.8619 20.66 142.4520 20.6 142.0321 20.54 141.6222 20.48 141.2023 20.41 140.7224 20.35 140.3125 20.28 139.8326 20.22 139.4127 20.15 138.9328 20.08 138.4529 20.01 137.9630 19.94 137.4831 19.87 137.0032 19.8 136.5233 19.73 136.0334 19.65 135.4835 19.58 135.0036 19.5 134.4537 19.42 133.9038 19.35 133.4139 19.27 132.8640 19.19 132.3141 19.11 131.7642 19.03 131.2143 18.95 130.6644 18.86 130.0445 18.78 129.4846 18.7 128.9347 18.61 128.3148 18.53 127.7649 18.44 127.1450 18.35 126.52

51 18.26 125.9052 18.17 125.2853 18.08 124.6654 17.99 124.0455 17.9 123.4256 17.81 122.8057 17.71 122.1158 17.62 121.4959 17.53 120.8760 17.43 120.1861 17.33 119.4962 17.24 118.8763 17.14 118.1864 17.04 117.4965 16.94 116.8066 16.84 116.1167 16.74 115.4268 16.64 114.7369 16.53 113.9770 16.43 113.2871 16.33 112.5972 16.22 111.8373 16.12 111.1474 16.01 110.3975 15.9 109.6376 15.79 108.8777 15.69 108.1878 15.58 107.4279 15.47 106.6680 15.36 105.9081 15.24 105.0882 15.13 104.3283 15.02 103.5684 14.9 102.7385 14.79 101.9786 14.67 101.1587 14.56 100.3988 14.44 99.5689 14.32 98.7390 14.2 97.9191 14.09 97.1592 13.97 96.3293 13.84 95.4294 13.72 94.6095 13.6 93.7796 13.48 92.9497 13.35 92.0598 13.23 91.2299 13.1 90.32

100 12.98 89.49101 12.85 88.60102 12.72 87.70103 12.59 86.81104 12.47 85.98

105 12.33 85.01106 12.2 84.12107 12.07 83.22108 11.94 82.32109 11.81 81.43110 11.67 80.46111 11.54 79.57112 11.4 78.60113 11.26 77.63114 11.13 76.74115 10.99 75.77116 10.85 74.81117 10.71 73.84118 10.57 72.88119 10.43 71.91120 10.28 70.88121 10.14 69.91122 9.99 68.88123 9.85 67.91124 9.7 66.88125 9.55 65.84126 9.41 64.88127 9.26 63.85128 9.11 62.81129 8.97 61.85130 8.84 60.95131 8.7 59.98132 8.57 59.09133 8.44 58.19134 8.32 57.36135 8.19 56.47136 8.07 55.64137 7.96 54.88138 7.84 54.05139 7.73 53.30140 7.62 52.54141 7.51 51.78142 7.41 51.09143 7.3 50.33144 7.2 49.64145 7.1 48.95146 7.01 48.33147 6.91 47.64148 6.82 47.02149 6.73 46.40150 6.64 45.78151 6.55 45.16152 6.46 44.54153 6.38 43.99154 6.3 43.44155 6.22 42.89156 6.14 42.33157 6.06 41.78158 5.98 41.23

159 5.91 40.75160 5.83 40.20161 5.76 39.71162 5.69 39.23163 5.62 38.75164 5.55 38.27165 5.49 37.85166 5.42 37.37167 5.35 36.89168 5.29 36.47169 5.23 36.06170 5.17 35.65171 5.11 35.23172 5.05 34.82173 4.99 34.40174 4.93 33.99175 4.88 33.65176 4.82 33.23177 4.77 32.89178 4.71 32.47179 4.66 32.13180 4.61 31.78181 4.56 31.44182 4.51 31.10183 4.46 30.75184 4.41 30.41185 4.36 30.06186 4.32 29.79187 4.27 29.44188 4.23 29.16189 4.18 28.82190 4.14 28.54191 4.09 28.20192 4.05 27.92193 4.01 27.65194 3.97 27.37195 3.93 27.10196 3.89 26.82197 3.85 26.54198 3.81 26.27199 3.77 25.99200 3.73 25.72