Live Load Calculations as Per is Standards

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



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



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



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



Terrain Category

Category Description



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 )



y = -1E-15x6 + 3E-12x5 - 2

0

0.2

0 100 20



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



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)



-09x4 + 7E-07x3 - 0.0001x2 + 0.0143x + 0.6277

300 400 500 600

Height





ped



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



mm

mm

Hertz

mm

mm

mm

km/hr

km/hr

km/hr

kgf

kgf

mm



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



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



Documents

Live Load Calculations as Per is Standards