Wind Loads

Wind loads are applied to all above ground pipe elements and fittings in global coordinate system. Load depend on angle between element axis and wind direction:

- uniform wind loads in global coordinate system on element

p - uniform wind load calculated according to selected code

ω - angle between element Xm vector and wind direction vector. When wind blow along the pipe the load is zero.  When wind blow perpendicular to pipe the load is greatest.

X,Y,Z - direction cosines of wind vector

To remove wind loads on some elements, set to zero the wind shape factor.

If wind and ice loads added simultaneously then diameter of insulation Dk (D) is increased by the ice layer thickness.

Available following codes for wind loads:

D – Insulation outer diameter (specified in pipe properties)

Cf – Wind shape factor (specified in pipe properties). If "Auto" option is on:

G=0.85

Kd=1

Kz – Velocity pressure exposure coefficient from table, depend on exposure (B,C,D)

D – Insulation outer diameter (specified in pipe properties)

GD=0.85

CD – Wind shape factor (specified in pipe properties). If "Auto" option is on:

D – Insulation outer diameter (specified in pipe properties)

Cp – Wind shape factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

– Wind shape factor (specified in pipe properties). If "Auto" option is on:

D – Insulation outer diameter (specified in pipe properties)

Cf – Wind shape factor (specified in pipe properties). If "Auto" option is on:

Dk – Insulation outer diameter (specified in pipe properties)

c - Wind shape factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

Cq – Wind shape factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

Cfig - Wind shape factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

Cp – Wind shape factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

Ca – Wind shape factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

Cp – Wind shape factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

Cf – Wind shape factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

Ca – Wind shape factor (specified in pipe properties)

Kre - correction factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

c - Wind shape factor (specified in pipe properties)

c – Wind shape factor (specified in pipe properties)

D – Insulation outer diameter (specified in pipe properties)

Property

Description

Insulation Outer Diameter

Insulation outer diameter is used for calculation of upwind surface area. If wind and ice loads added simultaneously then diameter of insulation is increased by the ice layer thickness automatically

Elevation of Start/End Node

Greatest elevation from ground surface is used for calculation of wind load

Wind Direction

Select wind direction in global coordinate system. If "other" option is selected, then angles between wind direction vector and global axes X, Y, Z should be entered.

Number of wind directions is unlimited

First Frequency, f1

First natural frequency of the piping system. Can be obtained from normal modes analysis

Wind Region

  • SP 20.13330.2016 (Russia)

Select wind region number from maps

  • AZ/NZS 1170.2:2011 (New Zeland)

A1, A2, A3, A4, A5, A6, A7, W, B, C, D

 

Basic Wind Speed

  • ASCE 7-16 (USA)

V, section 26.5

  • EN 1991-1-4:2005+A1:2010 (European Union)

Fundamental Value of Basic wind speed Vb,0

  • IS.875.3.1987 (India)

Vb

  • IBC 2012 (International)

V

  • UBC 1997 (International)

V

  • NSR-10 (Colombia)

V

  • AZ/NZS 1170.2:2011 (New Zeland)

  • NBC 2010 (Canada)

V

  • KBC 2016 (Korea)

Vo

  • NBR 06123-1988 (Brazil)

Vo

  • BS 6399-2 (Britain)

Vb

  • TKP EN 1991-1-4 2009 (Belarus)

Same as for EN 1991-1-4:2005+A1:2010

  • CNS (Taiwan)

  • CFE 2008 (Mexico)

VR

  • Wind Velocity vs Elevation

V

Basic Wind Pressure

  • GB 50009-2012 (China)

w0

  • NBC 2010 (Canada)

q

  • Wind Pressure vs Elevation

pN

Hill Type

  • ASCE 7-16 (USA)

  • IBC 2012 (International): Same as ASCE 7-16

  • CNS (Taiwan): Same as ASCE 7-16

  • NSR-10 (Colombia): Same as ASCE 7-16

  • CFE 2008 (Mexico): Same as ASCE 7-16

  • KBC 2016 (Korea):

Average slope,

  • KBC 2016 (Korea): Average hill slope

Height of Hill, H

  • ASCE 7-16 (USA): H - height of hill or escarpment

  • IBC 2012 (International): H - height of hill or escarpment

  • CNS (Taiwan): H - height of hill or escarpment

  • NSR-10 (Colombia): H - height of hill or escarpment

  • KBC 2016 (Korea): H - height of hill or escarpment

  • CFE 2008 (Mexico): H - height of hill or escarpment

Crest Distance, Lh

  • ASCE 7-16 (USA): Lh - distance upwind of crest of hill or escarpment to where the difference in ground elevation is half the height of the hill or escarpment

  • IBC 2012 (International): Same as ASCE 7-16

  • CNS (Taiwan): Same as ASCE 7-16

  • NSR-10 (Colombia): Same as ASCE 7-16

  • KBC 2016 (Korea): Lu - distance upwind of crest of hill to where the difference in ground elevation is half the height of the hill

  • CFE 2008 (Mexico): Same as ASCE 7-16

Distance from Crest to Site, x

  • ASCE 7-16 (USA): x - distance upwind or downwind of crest (+ upwind, - downwind)

  • IBC 2012 (International): Same as ASCE 7-16

  • CNS (Taiwan): Same as ASCE 7-16

  • NSR-10 (Colombia): Same as ASCE 7-16

  • CFE 2008 (Mexico): Same as ASCE 7-16

  • KBC 2016 (Korea): Same as ASCE 7-16

Importance factor, Iw

  • UBC 1997

  • NBC 2010 (Canada)

  • KBC 2016 (Korea)

Wind Exposure

Terrain Category

  • SP 20.13330.2016 (Russia): A, B, C

  • ASCE 7-16 (USA): B, C, D

  • IBC 2012 (International): Same as ASCE 7-16

  • NSR-10 (Colombia):

  • KBC 2016 (Korea):

  • CNS (Taiwan): A,B,C

  • UBC 1997: B, C, D

  • GB 50009-2012 (China)

  • IS.875.3.1987 (India)

  • AZ/NZS 1170.2:2011 (New Zeland)

  • NBC 2010 (Canada)

Open Terrain, Rough Terrain

  • EN 1991-1-4:2005+A1:2010 (European Union)

  • CFE 2008 (Mexico)

Pipe Surface Condition

  • GB 50009-2012 (China)

Smooth (0), Rough (0.02d), Very Rough (0.08d)

  • IS.875.3.1987 (India)

Smooth, Rough

  • NBR 06123-1988 (Brazil)

Smooth (0), Rough (0.02D), Very Rough (0.08D)

Total Wind Height, H

  • GB 50009-2012 (China): H

  • IS.875.3.1987 (India): h

  • NBC 2010 (Canada): H

  • NBR 06123-1988 (Brazil): h

  • BS 6399-2 (Britain)

Ho - upwind building height

  • CFE 2008 (Mexico)

Zt

Risk Factor, k1

Equipment class

  • IS.875.3.1987 (India)

Topography Factor

  • IS.875.3.1987 (India): k3

  • NBR 06123-1988 (Brazil): S1

Cardinal Direction

Hill Shape Multiplier, Mh

Lee Effect Multiplier, Mlee

Surface Roughness Height, hr

Shielding Multiplier, Ms

  • AZ/NZS 1170.2:2011 (New Zeland)

Cardinal direction: N, NE, E, SE, S, SW, W, NW, Any Direction

Site Elevation (Altitude)

  • AZ/NZS 1170.2:2011 (New Zeland)

Site elevation above mean sea level, in metres

  • BS 6399-2 (Britain)

  • CFE 2008 (Mexico)

hm

Surface Roughness, hr

  • AZ/NZS 1170.2:2011 (New Zeland)

hr, 0.003 mm - 15 mm

  • CFE 2008 (Mexico)

hr, 0.003 mm - 15 mm

Temperature

  • CFE 2008 (Mexico)

t - ambient air temperature

Statistical factor, S3

Roughness category

Dimension class

  • NBR 06123-1988 (Brazil)

Directional Factor

  • BS 6399-2 (Britain): Sd

  • EN 1991-1-4:2005+A1:2010 (European Union): Cdir

The value of the directional factor, Cdir, for various wind directions may be found in the National

Annex. The recommended value is 1,0

Seasonal Factor

  • BS 6399-2 (Britain): Ss

  • EN 1991-1-4:2005+A1:2010 (European Union): Cseason

The value of the season factor, Cseason, may be given in the National Annex. The recommended

value is 1.0

Building-type factor, Kb

Probability factor, Sp

Upwind Building Spacing, Xo

Upwind Building Height, Ho

Pipe Location

Closest Distance to Sea Upwind

Size Effect Factor, Ca

  • BS 6399-2 (Britain)

Pipe Location:

  • Site in country or up to 2 km into town

  • Site in town, extending < 2 km upwind from the site

Size Effect Factor Ca

Structural Factor CsCd

Turbulence Factor KI

  • EN 1991-1-4:2005+A1:2010 (European Union)

Turbulence Factor KI

The value of turbulence factor may be given in the National Annex. The recommended value is 1.0

Snubbers

Define the snubbers are active or not active for wind loads

Menu Access

Dialog window opens automatically when creating a new analysis file or opening an existing analysis file. To open this window in an open file, use  File > Project Settings