wind load calculations per india std(with vortex shedding)

8/3/2019 Wind Load Calculations Per India Std(With Vortex Shedding)

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PV Elite 2011 SP1 Licensee: MABEL ENGINEERING PVT LTD

FileName : O2 REACTOR 2 (rev-4) --------------------------

Wind Load Calculation : Step: 8 10:28a Nov 14,2011

Wind Load Calculations per India Std. IS-875 (Part-3) - 1987, Amd. 1&2 (2003):

Actual Vessel Height to Diameter ratio 10.947

Force Coefficient per IS:875 Table 23, Cf 0.909

User Entered Basic Wind Speed 180.0 km/hr

Base Elevation 0.00 m

Wind Zone Number 6Risk Factor (k1) 1.0800

Terrain Category 2

Equipment Class B

Topography Factor (k3) 1.0000

Use Gust Response Factor (Dynamic Analysis) Yes

User entered Beta Value ( Operating Case ) 0.0100

Checking the requirement for Dynamic Effect of wind (7.1):

Vessel Operating Natural Frequency 0.839 Hz

Vessel Height to Diameter ratio 10.947

Warning: Vessel Natural frequency is < 1 Hz.

Warning: Vessel height to diameter ratio (10.947) is > 5.

Note: As per Section 7.1, Dynamic effects of wind should be considered. TheCross-Wind dynamic effects can be considered using the Vortex Sheddingwhich can be invoked from Design Constraints tab. While the Along-Windeffects can be considered using Gust Response Factor method, which can beinvoked from the Wind Load tab.

Computation of Gust Response Factors per IS-875

Breadth of the structure (average vessel diameter) b 3328.66 mm

Total Height of the structure (including base elevation) h 37144.50 mm

Lateral Correlation constant, Cy 10.0

Longitudinal Correlation constant, Cz 12.0

Peak factor gf times the roughness factor r from Fig. 8 gfr 1.2143A measure of turbulence length scale from Fig. 8 L(h) 1195.73

Background Factor from Figure 9 B 0.7854

Lambda for use in Figure 9 which is Cy/Cz * b/h Lambda 0.0062

Abcissa value for use in Fig. 9 Czh/L(h) 0.3728

phi which is gfr*sqrt(B)/4 (may be 0 in some cases) phi 0.0000

Abcissa value (fo)L(h)/Vh used in Figure 11 (non-constant) fo`

Abcissa value Cz(fo)(h)/Vh used in Figure 10 (non-constant) Fo

Gust Factor - Operating Case, G(ope):

= 1.0 + gfr * (B * (1 + phi) + (Sope * Eope) / ope)**

Gust Factor - Empty Case, G(emp):

= 1.0 + gfr * (B * (1 + phi) + (Semp * Eemp) / emp)**

Gust Factor - Hydrotest Case, G(tst):

= 1.0 + gfr * (B * (1 + phi) + (Stst * Etst) / tst)**

From fo` fo` fo` FO FO FO E E

(ope) (emp) (tst) (ope) (emp) (tst) (ope) (emp)

-----------------------------------------------------------------------

10 27.74 72.90 28.60 8.62 22.65 8.89 0.0563 0.0297

20 27.74 72.90 28.60 8.62 22.65 8.89 0.0563 0.0297

30 27.74 72.90 28.60 8.62 22.65 8.89 0.0563 0.0297

40 27.74 72.90 28.60 8.62 22.65 8.89 0.0563 0.0297

50 27.55 72.43 28.42 8.56 22.50 8.83 0.0565 0.0299

60 26.76 70.34 27.60 8.31 21.85 8.57 0.0576 0.0304

70 26.01 68.37 26.83 8.08 21.24 8.33 0.0587 0.0310


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80 25.61 67.31 26.41 7.96 20.91 8.20 0.0593 0.0313

90 25.29 66.49 26.09 7.86 20.65 8.10 0.0598 0.0316

100 24.89 65.42 25.67 7.73 20.32 7.97 0.0604 0.0319

110 24.59 64.63 25.36 7.64 20.08 7.88 0.0609 0.0322

120 24.33 63.95 25.09 7.56 19.87 7.79 0.0613 0.0324

130 24.08 63.29 24.83 7.48 19.66 7.71 0.0618 0.0326

140 23.88 62.76 24.63 7.42 19.50 7.65 0.0621 0.0328150 23.72 62.36 24.47 7.37 19.37 7.60 0.0624 0.0330

160 23.56 61.93 24.30 7.32 19.24 7.55 0.0626 0.0331

170 23.39 61.49 24.13 7.27 19.10 7.50 0.0629 0.0333

180 23.22 61.03 23.95 7.21 18.96 7.44 0.0633 0.0334

190 23.05 60.58 23.77 7.16 18.82 7.38 0.0636 0.0336

200 22.90 60.20 23.62 7.11 18.70 7.34 0.0638 0.0337

From E S S S G G G

(tst) (ope) (emp) (tst) (ope) (emp) (tst)

--------------------------------------------------------------------

10 0.0551 0.2499 0.1030 0.2426 2.7974 1.0000 1.0000

20 0.0551 0.2499 0.1030 0.2426 2.7974 1.0000 1.0000

30 0.0551 0.2499 0.1030 0.2426 2.7974 1.0000 1.0000

40 0.0551 0.2499 0.1030 0.2426 2.7974 1.0000 1.0000

50 0.0554 0.2514 0.1039 0.2442 2.8034 1.0000 1.000060 0.0564 0.2580 0.1076 0.2510 2.8301 1.0000 1.0000

70 0.0575 0.2642 0.1112 0.2574 2.8560 1.0000 1.0000

80 0.0581 0.2676 0.1131 0.2609 2.8702 1.0000 1.0000

90 0.0586 0.2702 0.1146 0.2636 2.8815 1.0000 1.0000

100 0.0592 0.2736 0.1166 0.2671 2.8962 1.0000 1.0000

110 0.0597 0.2761 0.1180 0.2697 2.9073 1.0000 1.0000

120 0.0601 0.2783 0.1192 0.2719 2.9169 1.0000 1.0000

130 0.0605 0.2804 0.1204 0.2741 2.9264 1.0000 1.0000

140 0.0608 0.2821 0.1214 0.2758 2.9341 1.0000 1.0000

150 0.0611 0.2833 0.1221 0.2771 2.9399 1.0000 1.0000

160 0.0614 0.2847 0.1229 0.2785 2.9463 1.0000 1.0000

170 0.0617 0.2861 0.1237 0.2800 2.9527 1.0000 1.0000

180 0.0620 0.2875 0.1245 0.2815 2.9596 1.0000 1.0000

190 0.0623 0.2890 0.1253 0.2830 2.9664 1.0000 1.0000

200 0.0625 0.2902 0.1260 0.2842 2.9721 1.0000 1.0000

Design Wind Speed (Vz):

= Basic Wind Speed * k1 * k2 * k3

Note: As Gust Response Factor Method is used, K2 is read from table 33.

Height Factor :

= 0.6 * Vz

Element Wind Load (ope):= Wind Area * Cf * Height Factor * G(ope)

Element Wind Load (emp):

= Wind Area * Cf * Height Factor * G(emp)

Element Wind Load (tst):

= Wind Area * Cf * Height Factor * G(tst)

From Height k1 k2 k3 Vz Cf

m m/sec

------------------------------------------------------------

10 3.47 1.0800 0.6700 1.0000 36.18 0.9095

20 7.19 1.0800 0.6700 1.0000 36.18 0.9095

30 7.47 1.0800 0.6700 1.0000 36.18 0.9095

40 8.47 1.0800 0.6700 1.0000 36.18 0.9095

50 10.44 1.0800 0.6744 1.0000 36.42 0.9095

60 12.44 1.0800 0.6944 1.0000 37.50 0.9095

70 14.44 1.0800 0.7144 1.0000 38.58 0.9095


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80 15.94 1.0800 0.7256 1.0000 39.18 0.9095

90 17.44 1.0800 0.7346 1.0000 39.67 0.9095

100 19.44 1.0800 0.7466 1.0000 40.32 0.9095

110 21.44 1.0800 0.7558 1.0000 40.81 0.9095

120 23.44 1.0800 0.7638 1.0000 41.24 0.9095

130 25.44 1.0800 0.7718 1.0000 41.67 0.9095

140 27.07 1.0800 0.7783 1.0000 42.02 0.9095150 28.32 1.0800 0.7833 1.0000 42.29 0.9095

160 29.69 1.0800 0.7888 1.0000 42.59 0.9095

170 31.44 1.0800 0.7943 1.0000 42.89 0.9095

180 33.44 1.0800 0.8003 1.0000 43.21 0.9095

190 35.44 1.0800 0.8063 1.0000 43.54 0.9095

200 37.14 1.0800 0.8114 1.0000 43.81 0.9095

Note: Vortex shedding loads have been applied at the usersrequest, even though the vessel was determined to bestable and not susceptible to vortex shedding.

Vortex Shedding Loads, per NBC 1990 Supplement, pages 149-150

Compute the critical wind speed using the weighted averagediameter of the top one-third of the vessel [Vh(ope)]= Fn(ope) * Davg / 0.2 * 0.6818

= 0.8391 * 10.4987 / 0.2 * 0.6818

= 30.034 mile/hr ; 48.334 km/hr

Compute the aspect ratio (gamma) for the entire structure [Gamma]= (Total Height) / Sum of the Wind Area

= 36440.00 / 1255256 = 10.5785

Determine the Velocity Pressure Qh(ope) (English Units only)= 0.5 * 0.0668 * Rho * Vh(ope)

= 0.5 * 0.0668 * 0.0749 * 30.034 = 2.259 psf ; 11.0273 kgf/m

Compute the equivalent force per unit area which will act on the topone-third of the vessel [F/area]:= (qh(ope)*C1)/[(Gamma)*(Beta(ope)-(C2*Rho*Davg/M3))]

=(2.259*2.4)/[(10.58)*(0.0100-(0.60*0.0749*266.6667/10.2))]

= 85.8687 kgf/m

In a similar manner, the values of F/area for the Empty and Testcases are computed.F/area(empty) = 2184.2981 , F/area(test) = 0.0000 kgf/m

The following table contains results for Vortex Shedding Case (Ope).

Wind Load Calculation

| | Wind | Wind | Wind | Height | Element |

From| To | Height | Diameter | Area | Factor | Wind Load || | mm | mm | cm | kgf/m | kgf |

---------------------------------------------------------------------------

10| 20| 3470.00 | 4008.00 | 278155. | ... | ... |

20| 30| 7190.00 | 3998.40 | 19992.0 | ... | ... |

30| 40| 7465.00 | 2385.60 | 1192.80 | ... | ... |

40| 50| 8465.00 | 3998.40 | 77968.8 | ... | ... |

50| 60| 10440.0 | 3998.40 | 79968.0 | ... | ... |

60| 70| 12440.0 | 3998.40 | 79968.0 | ... | ... |

70| 80| 14440.0 | 3998.40 | 79968.0 | ... | ... |

80| 90| 15940.0 | 3998.40 | 39984.0 | ... | ... |

90| 100| 17440.0 | 3993.60 | 79872.0 | ... | ... |

100| 110| 19440.0 | 3993.60 | 79872.0 | ... | ... |

110| 120| 21440.0 | 3993.60 | 79872.0 | ... | ... |


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120| 130| 23440.0 | 3993.60 | 79872.0 | ... | ... |

130| 140| 25440.0 | 3993.60 | 79872.0 | 85.8687 | 623.762 |

140| 150| 27065.0 | 3993.60 | 49920.0 | 85.8687 | 389.852 |

150| 160| 28315.0 | 3993.60 | 49920.0 | 85.8687 | 389.852 |

160| 170| 29690.0 | 3988.80 | 59832.0 | 85.8687 | 467.260 |

170| 180| 31440.0 | 3988.80 | 79776.0 | 85.8687 | 623.013 |

180| 190| 33440.0 | 3988.80 | 79776.0 | 85.8687 | 623.013 |190| 200| 35440.0 | 3988.80 | 79776.0 | 85.8687 | 623.013 |

200| 210| 37144.5 | 3984.00 | 51943.1 | 85.8687 | 405.651 |

The following table contains results for Vortex Shedding Case (Empty).



From| To | Height | Diameter | Area | Factor | Wind Load |

| | mm | mm | cm | kgf/m | kgf |

---------------------------------------------------------------------------

10| 20| 3470.00 | 4008.00 | 278155. | ... | ... |

20| 30| 7190.00 | 3998.40 | 19992.0 | ... | ... |

30| 40| 7465.00 | 2385.60 | 1192.80 | ... | ... |

40| 50| 8465.00 | 3998.40 | 77968.8 | ... | ... |50| 60| 10440.0 | 3998.40 | 79968.0 | ... | ... |

60| 70| 12440.0 | 3998.40 | 79968.0 | ... | ... |

70| 80| 14440.0 | 3998.40 | 79968.0 | ... | ... |

80| 90| 15940.0 | 3998.40 | 39984.0 | ... | ... |

90| 100| 17440.0 | 3993.60 | 79872.0 | ... | ... |

100| 110| 19440.0 | 3993.60 | 79872.0 | ... | ... |

110| 120| 21440.0 | 3993.60 | 79872.0 | ... | ... |

120| 130| 23440.0 | 3993.60 | 79872.0 | ... | ... |

130| 140| 25440.0 | 3993.60 | 79872.0 | 2184.30 | 15867.0 |

140| 150| 27065.0 | 3993.60 | 49920.0 | 2184.30 | 9916.90 |

150| 160| 28315.0 | 3993.60 | 49920.0 | 2184.30 | 9916.90 |

160| 170| 29690.0 | 3988.80 | 59832.0 | 2184.30 | 11886.0 |

170| 180| 31440.0 | 3988.80 | 79776.0 | 2184.30 | 15848.0 |

180| 190| 33440.0 | 3988.80 | 79776.0 | 2184.30 | 15848.0 |

190| 200| 35440.0 | 3988.80 | 79776.0 | 2184.30 | 15848.0 |200| 210| 37144.5 | 3984.00 | 51943.1 | 2184.30 | 10318.8 |

End of Vortex Shedding Calculations

Wind Vibration Calculations

This evaluation is based on work by Kanti Mahajan and Ed Zorilla

Nomenclature

Cf - Correction factor for natural frequency

D - Average internal diameter of vessel mm

Df - Damping Factor < 0.75 Unstable, > 0.95 Stable

Dr - Average internal diameter of top half of vessel mmf - Natural frequency of vibration (Hertz)

f1 - Natural frequency of bare vessel based on a unit value of (D/L)(104)

L - Total height of structure mm

Lc - Total length of conical section(s) of vessel mm

tb - Uncorroded plate thickness at bottom of vessel mm

V30 - Design Wind Speed provided by user km/hr

Vc - Critical wind velocity km/hr

Vw - Maximum wind speed at top of structure km/hr

W - Total corroded weight of structure kgf

Ws - Cor. vessel weight excl. weight of parts which do not effect stiff. kgf

Z - Maximum amplitude of vibration at top of vessel mm

Dl - Logarithmic decrement ( taken as 0.03 for Welded Structures )

Vp - Vib. Chance,


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P30 - wind pressure 30 feet above the base

Check other Conditions and Basic Assumptions:#1 - Total Cone Length / Total Length < 0.5

4155.000 / 36439.996 = 0.114

#2 - ( D / L ) * 104

< 8.0 (English Units)- ( 10.92 / 119.55 ) * 10

4 = 7.641

Compute the vibration possibility. If Vp > 0.400E-06 no chance. [Vp]:= W / ( L * Dr)

= 315134 / ( 36440.00 * 3200.000 )

= 0.84454E-06

Since Vp is > 0.400E-06 no further vibration analysis is required !

The Natural Frequency for the Vessel (Ope...) is 0.83915 Hz.



From| To | Height | Diameter | Area | Factor | Wind Load |

| | mm | mm | cm | kgf/m | kgf |

---------------------------------------------------------------------------

10| 20| 3470.00 | 4008.00 | 278155. | 80.1110 | 7367.27 |

20| 30| 7190.00 | 3998.40 | 19992.0 | 80.1110 | 529.512 |

30| 40| 7465.00 | 2385.60 | 1192.80 | 80.1110 | 31.5927 |

40| 50| 8465.00 | 3998.40 | 77968.8 | 80.1110 | 2065.10 |

50| 60| 10440.0 | 3998.40 | 79968.0 | 81.1666 | 2150.55 |

60| 70| 12440.0 | 3998.40 | 79968.0 | 86.0521 | 2301.71 |

70| 80| 14440.0 | 3998.40 | 79968.0 | 91.0805 | 2458.51 |

80| 90| 15940.0 | 3998.40 | 39984.0 | 93.9690 | 1274.57 |

90| 100| 17440.0 | 3993.60 | 79872.0 | 96.3144 | 2619.84 |

100| 110| 19440.0 | 3993.60 | 79872.0 | 99.4866 | 2720.01 |

110| 120| 21440.0 | 3993.60 | 79872.0 | 101.932 | 2797.51 |

120| 130| 23440.0 | 3993.60 | 79872.0 | 104.101 | 2866.49 |

130| 140| 25440.0 | 3993.60 | 79872.0 | 106.294 | 2936.39 |

140| 150| 27065.0 | 3993.60 | 49920.0 | 108.092 | 1871.16 |

150| 160| 28315.0 | 3993.60 | 49920.0 | 109.485 | 1899.06 |

160| 170| 29690.0 | 3988.80 | 59832.0 | 111.028 | 2313.22 |

170| 180| 31440.0 | 3988.80 | 79776.0 | 112.599 | 3134.73 |

180| 190| 33440.0 | 3988.80 | 79776.0 | 114.306 | 3189.67 |

190| 200| 35440.0 | 3988.80 | 79776.0 | 116.026 | 3245.13 |

200| 210| 37144.5 | 3984.00 | 51943.1 | 117.503 | 2143.99 |

Note: The Wind Pressures in the table above have been modifiedby the Wind Force Scalar value defined in the input.

PV Elite is a trademark of Intergraph CADWorx & Analysis Solutions, Inc. 2011

wind load calculations per india std(with vortex shedding)

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