live load calculations as per is standards
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8/13/2019 Live Load Calculations as Per is Standards
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Wind Data
Wind Design Code IS:875
Base Elevation 4500 mm
Wind Zone Number 2
Basic Wind Speed 50 m/s
Risk Factor k1 1.08Terrain Category 2
Equipment Class 1
Topography Facto k3 1
Correction factor for natural frequency Cf 0.7
Wind Diameter Multiplier 1
Design Wind Spee Vz Basic Wind Speed *k1*k2*k3
Height Factor 0.6*Vz2 N/m
2
Element Wind Load Wind Area *Cf *Height Factor
From k1 k2 k3 Vz Cf
10 1.08 1 1 54 0.7
20 1.08 1.01784 1 54.9633 0.7
30 1.08 1.01784 1 54.9633 0.7
40 1.08 1.01784 1 54.9633 0.7
50 1.08 1.01784 1 54.9633 0.7
60 1.08 1.01784 1 54.9633 0.7
Wind Wind Wind Height
From To Height Diameter Area Factor
mm mm cm2
Kg/m2
10 20 7750 3624 235560 178.349
20 30 11000 25.4 0 184.768
30 40 11000 25.4 0 184.768
40 50 11000 1257.3 0 184.768
50 60 11000 38.1 0 184.768
60 70 11050.8 38.1 0 184.768
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Element Cumulative Distance of cg Wind
Wind Load Wind Shear to support Bending
kgf kgf mm Kg-m
294 82613 2940.82613 3250 9557 68492
0 6500
0 6500
0 6500
0 6500
0 6550.8
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From To Descritpion ID t L D Ρ W cg of segment
mm mm mm mm kg/m3
kg mm
10 20 Skirt 3600 12 6500 7833 6932.986 3250
20 30 Elliptical 0 12.7 0 7833 0.074298 0
30 40 Cylinder 0 12.7 0 7833 0 0
40 50 Cone 0 19.05 0 2438.4 7833 718.5994 0
50 60 Cylinder 0 19.05 0 7833 0 0
60 70 Elliptical 0 19.05 0 7833 0.250757 50.8
Parameters
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cg wrt to
bottom of shell
Distance
form Base
Height of
"From" Node k2 k2
mm mm m
3250 7750 4.5 0.976666 1
6500 11000 11 1.017838 1.017838
6500 11000 11 1.017838 1.017838
6500 11000 11 1.017838 1.017838
6500 11000 11 1.017838 1.017838
6550.8 11050.8 11 1.017838 1.017838
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Terrain Category
Category Description
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1 Exposed open terrain with few or no obstruction including open sea coasts a
2 Open terrain wih scattered obstruction having heights between 1.5 to 10 mtr
3 This is the terrain with numerous closely spaced obstructions which have buil
4 Terrain consisting of large obstructions. This includes large urban centres and
Equipment Class
1 Class A <20 m2 Class B >20 m and <50 m
3 Class C > 50 m
Topography Factor
1 Upwind slope < 3 °
1.36 Upwind slope > 3 °
K2 factors to obtain design wind speed variation with height in different terrains
Height (z)
(m)
Terrain
Category 1
Terrain
Category 2
Terrain
Category 3
Terrain
Category 4
0-10 10 1.05 1 0.91 0.8
10-15 15 1.09 1.05 0.97 0.8
15-20 20 1.12 1.07 1.01 0.8 Value
20-30 30 1.15 1.12 1.06 0.97 Height
30-50 50 1.2 1.17 1.12 1.1 10
50-100 100 1.26 1.24 1.2 1.2 15
100-150 150 1.3 1.28 1.24 1.24 10
150-200 200 1.32 1.3 1.27 1.27
200-250 250 1.34 1.32 1.29 1.28 10
250-300 300 1.35 1.34 1.31 1.3 10
300-350 350 1.37 1.36 1.32 1.31
300-400 400 1.38 1.37 1.34 1.32
400-450 450 1.39 1.38 1.35 1.33
450-500 500 1.4 1.39 1.36 1.34
Terrain and height multiplier (k2)
y = -9E-16x6 + 2E-12x5 - 1
y = -2E-15x6 + 3E-12x5 - 2
y = -9E-16x6 + 2E-12x5 - 1
0.4
0.6
0.8
1
1.2
1.4
1.6
H e i g h t M u l t i p l i e r ( k 2 )
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y = -1E-15x6 + 3E-12x5 - 2
0
0.2
0 100 20
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Zone
Number
Basic Wind
Speed (m/s) Risk Factor
6 55 1.08
5 50 1.08
4 47 1.073 44 1.07
2 39 1.06
1 33 1.05
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d treeless plains
. This categeroy is generally used for design purpose
dings up to 10 mtr in height. This include well wooded areas, towns and industrial areas fully or parrially develo
well developed industrial centres.
10 m
Category1 Category2 Category3 Category4
1.05 1 0.91 0.8
1.09 1.05 0.97 0.8
1.05 1 0.91 0.8
1.0610902 1.0118902 0.9271803 0.7613803 Polynomial
1.0610902 1.0118902 0.9271803 0.7613803
Interpolation Table
E-09x4 + 4E-07x3 - 8E-05x2 + 0.0075x + 0.9445
-09x4 + 6E-07x3 - 0.0001x2 + 0.0098x + 0.8386
-09x4 + 4E-07x3 - 7E-05x2 + 0.0065x + 1.0027
Category 2Category 3
Category 4
Category1
Poly. (Category 2)
Poly. (Category 3)
Poly. (Category 4)
Poly. (Category1)
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-09x4 + 7E-07x3 - 0.0001x2 + 0.0143x + 0.6277
300 400 500 600
Height
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ped
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Wind Vibration Calculations
Correction factor for natural frequency Cf
Average internal diameter of vessel D
Damping factor Df
Average internal diameter of top of vessel Dr
Natural frequency of vibration f
Natural frequency o bare vessel based on a unit value of (D / L2) ( 10 ^ 4) f1Total height of structure L
Total length o conical section (s) of vessel Lc
Uncorroded plate thickness at bottom of vessel tb
Design Wind Speed provided by user V30
Critical wind velocity Vc
Maximum Wind Speed at top of structure Vw
Total corroded weight of structure W
Cor. Vessel Weight excl. weight of parts which do not effect stiff. Ws
Macimum amplitude of vibration at top of vessel Z
Logarithmic decrement ( taken as 0.03 for welded structures ) D1
vibration Possibility , <= 0.32037 * 10^-6 (High); Vp
Wind pressure 30 feet above the base P30
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mm
mm
Hertz
mm
mm
mm
km/hr
km/hr
km/hr
kgf
kgf
mm
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Soil Factor β 3
Importance Factor I 5
Zone Number 2
Value of αo per table 2 and Zone 0.05
Horizontal Seismic Coefficient αh β * I * αo
0.06
Earthquake Element Load Earthquake Weight * αh
Earthquake Earthquake Earthquake Earthquake Earthquake
From To Height Weight Element load Shear Bending
mm kgf kgf kgf kg-m
10 20 3250 6932.9863 415.979179 459.11465 1632.313620 30 6500 0.0742982 0.00445789 43.135467 0.0007643
30 40 6500 0 0 43.131009 0.0007643
40 50 6500 718.5994 43.1159639 43.131009 0.0007643
50 60 6500 0 0 0.0150454 0.0007643
60 70 6550.8 0.2507566 0.0150454 0.0150454 0.0007643
Seismic Analysis Result per IS-1893 Seismic Coefficient Method
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Value
6.0
2.0
2.0
1.5
1.0
Type Value
I 1
II 1
1.2
III 1
1.5
Combined or Isolated Rcc footings with tiebeams 1.2
Sr. No. Zone
Number
i) V
ii) IViii) III
iv) II
v) I
Values of Basic Seismic Coefficients and Seismic Zone Factors in different Zones
Importance Factor
Soil Factor
0.04
0.40
0.250.20
Method
Response Spectrum
Method
0.05
Method
Seismic Coefficient
0.08
0.05
average acceleration
0.02
0.01
0.10
well foundations or isolated RCC footings without
tiebeams or unreinforced strip foundations
Description
Rock or Hard soils
Medium Soils
Soft Soils
spectra to be used, Foαo
Seismic Coefficient
Basic horizontal Sesimic zone factor for
Category
All others
Note: Per the IS:1893 code, the above values are for guidance, the
may chose and appropriate factor based on economy, strategy and
other considerations
well foundations or isolated RCC footings without
tiebeams or unreinforced strip foundations
Importance service an community structures suc ashospitals, water towers, tanks, schools, important
bridges, power houses, monumental structures,
emergency buildings like telephone exchange and fire
brigade, large assembly structures like cinemas,
assembly halls and subway stations
Containment structures for atomic power reactors
Dams of all types
Containers of inflammable or poisonous gases/liquids
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