wind_load definition (1)

Calculate wind pressure (qz) according to american code ASCE 7-05METHOD 2-ANALYTICAL PROCEDURE

Calculation ReferenceASCE 7-05 Minimum design loads for buildings and other structuresChecked against calculated examples in Guide to the use of the Wind load provisions of ASCE 7-02 (Kishor C. Mehta and James M. Delehay)

Calculation Validation

Calculation Units1

select metric system

Remark: user input

Parameters

Velocity pressure exposure coeficient Kz (select category in combo-box)EXPOSURE B 1

Kz 1.1302605086z 160 ft

zg 1200 fta 7

Topographic factor Kzt

Kzt 1 0

K1 0.475 Lh 100K2 0.99 m 1.5K3 0.040762204 g 4

H 100H/Lh 0.5

Hill shapeUpwind / Downwind

3 2

Directionality factor KdKd 0.85 1

Purpose of calculation:

Wind Speed-Up over Hills, Ridges, and Escarpments

C17

orange cell requires user's input

B26

Height above local ground level, in feet (meters).

C26

input height where the pressure is acting

B34

Factor to account for shape of topographic feature and maximum speed-up effect

F34

Distance upwind of crest to where the difference in ground elevation is half the height of hill or escarpment, in feet (meters).

B35

Factor to account for reduction in speed-up with distance upwind or downwind of crest.

F35

Horizontal attenuation factor.

B36

Factor to account for reduction in speed-up with height above local terrain.

F36

Height attenuation factor.

F37

Height of hill or escarpment relative to the upwind terrain, in feet (meters).

input basic wind speed

Wind speedV 120 mph

Importance factor I I factor 1

2

2

Velocity pressure, qz evaluated at height z

qz 35.416034882 psf

= lookup(b12,l14:l15,o14:o15) = lookup(b12,l14:l15,o14:o15)

Checked against calculated examples in Guide to the use of the Wind load provisions of ASCE 7-02 (Kishor C. Mehta and James M. Delehay)

Units used in calculations

wind speed length pressure1 US mph ft psf2 EU m/s m N/m2

Exposure categor a zg [ft] zg[m]1 B 7 1200 365.762 C 9.5 900 274.323 D 11.5 700 213.36

2 dimensional 2-dimensio3-dimensional axisym. Hilsm 1 2 3

Upwind 1.5 1.5 1.5Downwind 1.5 4 1.5

K1 gB C D

1 2 dimensional 1.3 1.45 1.55 32 2-dimensional es 0.75 0.85 0.95 2.53 3-dimensional axi 0.95 1.05 1.15 4

Kd1 Buildings (MWFR and C&C systems) 0.852 Arched roofs 0.854 Chimneys, Tanks, and similar structure 0.9

Wind Speed-Up over Hills, Ridges, and Escarpments

5 Chimneys, Tanks, and similar structur 0.956 Chimneys, Tanks, and similar structur 0.957 Solid signs 0.858 Open Signs and Lattice Framework 0.859 Trussed Towers-Triangular, square, rec 0.85

10 Trussed Towers-All other cross section 0.95

1 2 3 4

0.87 1 1.15 1.150.77 1 1.15 1.15

IIIIIIIV

Non-Hurricane Prone Regions Hurricane Prone Regions

B C DCase 1 Case 2 Case 1&2 Case 1&2

0 0.715 0.720 0.730 0.7405060708090

100120140160180200250300350400450500

wind_load definition (1)

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