Wind loading (BS6399).pdf

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WIND LOADING (BS6399)

TEDDS calculation version 3.0.04

30000 3 0 0 0 0 Plan 30000 2 0 00 0 0 Elevation Building data

Type of roof; Flat

Length of building; L = 30000 mm

Width of building; W = 30000 mm

Height to eaves; H = 200000 mm

Eaves type; Sharp

Reference height; Hr = 200000 mm

Dynamic classification

Building type factor (Table 1); Kb = 1.0

Dynamic augmentation factor (1.6.1); Cr = [Kb × ( H / (0.1 m) )0.75] / ( 800 × log( H / (0.1 m) ) ) = 0.11 Site wind speed

Location; Other

Basic wind speed (Figure 6 BS6399:Pt 2) Vb = 23.0 m/s

Site altitude ∆S = 20 m

Upwind distance from sea to site dsea = 50 km

Direction factor Sd =1.00

Seasonal factor Ss = 1.00

Probability factor Sp = 1.00

Critical gap between buildings; g = 3200 mm

Topography

Type of feature; Hills and ridges

Actual length of upwind slope in wind direction; Lu = 50000 mm

Actual length downwind slope in wind direction; Ld = 50000 mm

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Upwind slope in upwind direction; ψU = Z / Lu = 0.40

Effective slope of topographic feature; ψe = 0.30

Effective length of upwind slope (cl 2.2.2.2.4); Le = Z / 0.3 = 66667 mm

Horiz distance of the site from the top of the crest; x = -5000 mm Altitude of upwind base of topographic feature; ∆T = 2.000 m

Site altitude; ∆S = 20.000 m

Topographic location factor (Figure 9a); s = 0.46

Topographic increment (Table 25); Sh = 0.6 × s = 0.27

Altitude factor; Sa = 1 + 0.001 × ∆T/1m = 1.00

Site wind speed Vs = Vb × Sa × Sd × Ss × Sp = 23.0 m/s

Terrain category; Country

Displacement height (sheltering effect excluded); Hd = 0mm

The velocity pressure for the windward face of the building with a 0 degree wind is to be considered as 3 parts as the height h is greater than 2b (cl.2.2.3.2)

The velocity pressure for the windward face of the building with a 90 degree wind is to be considered as 3 parts as the height h is greater than 2b (cl.2.2.3.2)

Dynamic pressure - windward wall (lower part) - Wind 0 deg

Reference height (at which q is sought); Href = 30000mm

Effective height; He = max(Href – Hd, 0.4 × Href) = 30000mm

Fetch factor (Table 22); Sc = 1.243

Turbulence factor (Table 22); St = 0.159

Gust peak factor; gt = 3.44

Terrain and building factor; Sb = Sc × (1 + (gt × St) + Sh) = 2.26

Effective wind speed; Ve = Vs × Sb = 52.2 m/s

Dynamic pressure; qs = 0.613 kg/m3 × Ve2 = 1.669 kN/m2 Dynamic pressure - windward wall, (middle part) - Wind 0 deg

Dynamic pressure; qs = 0.613 kg/m3 × Ve2 = 2.236 kN/m2 Dynamic pressure - windward wall (upper part), other walls and roof - Wind 0 deg

Dynamic pressure; qs = 0.613 kg/m3 × Ve2 = 2.297 kN/m2 Dynamic pressure - windward wall (lower part) - Wind 90 deg

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Dynamic pressure; qs = 0.613 kg/m3 × Ve2 = 1.669 kN/m2 Dynamic pressure - windward wall, (middle part) - Wind 90 deg

Dynamic pressure; qs = 0.613 kg/m3 × Ve2 = 2.236 kN/m2 Dynamic pressure - windward wall (upper part), other walls and roof - Wind 90 deg

Dynamic pressure; qs = 0.613 kg/m3 × Ve2 = 2.297 kN/m2 Size effect factors

Diagonal dimension for gablewall; aeg = 202.2 m

External size effect factor gablewall; Caeg = 0.770

Diagonal dimension for side wall; aes = 202.2 m

External size effect factor side wall; Caes = 0.770

Diagonal dimension for roof; aer = 42.4 m

External size effect factor roof; Caer = 0.867

Diagonal dimension for top windward side; aeus = 42.4 m

External size effect factor top windward side; Caeus = 0.867

Diagonal dimension for middle windward side; aems = 143.2 m

External size effect factor middle windward side; Caems = 0.791

Diagonal dimension for bottom windward side; aebs = 42.4 m

External size effect factor bottom windward side; Caebs = 0.867

Diagonal dimension for top windward gable; aeug = 42.4 m

External size effect factor top windward gable; Caeug = 0.867

Diagonal dimension for middle windward gable; aemg = 143.2 m

External size effect factor middle windward gable; Caemg = 0.791

Diagonal dimension for bottom windward gable; aebg = 42.4 m

External size effect factor bottom windward gable; Caebg = 0.867

Room/storey volume for internal size effect factor; Vi = 0.125 m3

Diagonal dimension for internal size effect factors;ai = 10 × ( Vi )1/3 = 5.000 m

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Pressures and forces

Net pressure; p = qs × cpe × Cae - qs × cpi × Cai;

Net force; Fw = p × Aref;

Roof loadcase 1 - Wind 0, cpi 0.20, -cpe

Zone Ext pressure coefficient, cpe Dynamic pressure, qs (kN/m2₎ External size factor, Cae Net Pressure, p (kN/m2₎ Area, Aref (m2) Net force, Fw (kN) A (-ve) -2.00 2.30 0.867 -4.44 45.00 -199.87 B (-ve) -1.40 2.30 0.867 -3.25 45.00 -146.11 C (-ve) -0.70 2.30 0.867 -1.85 360.00 -667.12 D (-ve) -0.20 2.30 0.867 -0.86 450.00 _-385.92

Total vertical net force; Fw,v = -1399.01 kN

Total horizontal net force; Fw,h = 0.00 kN Walls loadcase 1 - Wind 0, cpi 0.20, -cpe

Zone Ext pressure coefficient, cpe Dynamic pressure, qs (kN/m2₎ External size factor, Cae Net Pressure, p (kN/m2₎ Area, Aref (m2) Net force, Fw (kN) A -1.30 2.30 0.770 -2.76 1200.00 -3308.75 B -0.80 2.30 0.770 -1.87 4800.00 -8992.71 wb 0.85 1.67 0.867 0.90 900.00 _806.50 wm 0.85 2.24 0.791 1.06 4200.00 _4435.74 wu 0.85 2.30 0.867 1.23 900.00 _1109.69 l -0.50 2.30 0.770 -1.34 6000.00 -8059.18 Overall loading

Equiv leeward net force for upper section; Fl =Fw,wl / Aref,wl × Aref,wu = -1208.9 kN

Net windward force for upper section; Fw = Fw,wu = 1109.7 kN

Overall loading upper section; Fw,u = 0.85 × (1 + Cr) × (Fw - Fl) + Fw,h = 2194.0 kN

Equiv leeward net force for middle section; Fl =Fw,wl / Aref,wl × Aref,wm = -5641.4 kN

Net windward force for middle section; Fw = Fw,wm = 4435.7 kN

Overall loading middle section; Fw,m = 0.85 × (1 + Cr) × (Fw - Fl) = 9535.6 kN

Equiv leeward net force for bottom section; Fl =Fw,wl / Aref,wl × Aref,wb = -1208.9 kN

Net windward force for bottom section; Fw = Fw,wb = 806.5 kN

Overall loading bottom section; Fw,b = 0.85 × (1 + Cr) × (Fw - Fl) = 1907.1 kN Roof loadcase 2 - Wind 0, cpi -0.3, +cpe

Zone Ext pressure coefficient, cpe Dynamic pressure, qs (kN/m2₎ External size factor, Cae Net Pressure, p (kN/m2₎ Area, Aref (m2) Net force, Fw (kN) A (+ve) -2.00 2.30 0.867 -3.29 45.00 -148.18 B (+ve) -1.40 2.30 0.867 -2.10 45.00 -94.43 C (+ve) -0.70 2.30 0.867 -0.70 360.00 -253.67 D (+ve) 0.20 2.30 0.867 1.09 450.00 489.28

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Walls loadcase 2 - Wind 0, cpi -0.3, +cpe Zone Ext pressure coefficient, cpe Dynamic pressure, qs (kN/m2₎ External size factor, Cae Net Pressure, p (kN/m2₎ Area, Aref (m2) Net force, Fw (kN) A -1.30 2.30 0.770 -1.61 1200.00 _-1930.58 B -0.80 2.30 0.770 -0.73 4800.00 -3480.04 wb 0.85 1.67 0.867 1.73 900.00 _1557.71 wm 0.85 2.24 0.791 2.17 4200.00 9130.63 wu 0.85 2.30 0.867 2.38 900.00 2143.32 l -0.50 2.30 0.770 -0.19 6000.00 _-1168.34 Overall loading

Overall loading bottom section; Fw,b = 0.85 × (1 + Cr) × (Fw - Fl) = 1639.8 kN Roof loadcase 3 - Wind 90, cpi 0.20, -cpe

Zone Ext pressure coefficient, cpe Dynamic pressure, qs (kN/m2₎ External size factor, Cae Net Pressure, p (kN/m2₎ Area, Aref (m2) Net force, Fw (kN) A (-ve) -2.00 2.30 0.867 -4.44 45.00 -199.87 B (-ve) -1.40 2.30 0.867 -3.25 45.00 -146.11 C (-ve) -0.70 2.30 0.867 -1.85 360.00 -667.12 D (-ve) -0.20 2.30 0.867 -0.86 450.00 -385.92

Total horizontal net force; Fw,h = 0.00 kN Walls loadcase 3 - Wind 90, cpi 0.20, -cpe

Zone Ext pressure coefficient, cpe Dynamic pressure, qs (kN/m2₎ External size factor, Cae Net Pressure, p (kN/m2₎ Area, Aref (m2) Net force, Fw (kN) A -1.30 2.30 0.770 -2.76 1200.00 -3308.75 B -0.80 2.30 0.770 -1.87 4800.00 _-8992.71 wb 0.85 1.67 0.867 0.90 900.00 806.50 wm 0.85 2.24 0.791 1.06 4200.00 _4435.74 wu 0.85 2.30 0.867 1.23 900.00 1109.69 l -0.50 2.30 0.770 -1.34 6000.00 -8059.18 Overall loading

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Overall loading bottom section; Fw,b = 0.85 × (1 + Cr) × (Fw - Fl) = 1907.1 kN Roof loadcase 4 - Wind 90, cpi -0.3, +cpe

Zone Ext pressure coefficient, cpe Dynamic pressure, qs (kN/m2₎ External size factor, Cae Net Pressure, p (kN/m2₎ Area, Aref (m2) Net force, Fw (kN) A (+ve) -2.00 2.30 0.867 -3.29 45.00 -148.18 B (+ve) -1.40 2.30 0.867 -2.10 45.00 -94.43 C (+ve) -0.70 2.30 0.867 -0.70 360.00 _-253.67 D (+ve) 0.20 2.30 0.867 1.09 450.00 489.28

Total horizontal net force; Fw,h = 0.00 kN Walls loadcase 4 - Wind 90, cpi -0.3, +cpe

Zone Ext pressure coefficient, cpe Dynamic pressure, qs (kN/m2₎ External size factor, Cae Net Pressure, p (kN/m2₎ Area, Aref (m2) Net force, Fw (kN) A -1.30 2.30 0.770 -1.61 1200.00 -1930.58 B -0.80 2.30 0.770 -0.73 4800.00 -3480.04 wb 0.85 1.67 0.867 1.73 900.00 _1557.71 wm 0.85 2.24 0.791 2.17 4200.00 _9130.63 wu 0.85 2.30 0.867 2.38 900.00 2143.32 l -0.50 2.30 0.770 -0.19 6000.00 -1168.34 Overall loading

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A B A C D 7500 15000 7500 3 00 0 1 2 0 0 0 1 5 0 0 0 30000 3 0 0 0 0 W in d 0 o

Plan view - Flat roof

A 24000 6 0 0 0 B 30000 2 0 0 0 0 0 Side face l w_b wu wm 30000 2 0 0 0 0 0 W indward face w 30000 2 0 0 0 0 0 Leeward face

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A A B C D 7 5 0 0 1 5 0 0 0 7 5 0 0 3000 12000 15000 30000 3 0 0 0 0 Wind - 90o

Plan view - Flat roof

A 24000 6 0 0 0 B 30000 2 0 0 0 0 0 Side face l w_b wu wm 30000 2 0 0 0 0 0 W indward face w 30000 2 0 0 0 0 0 Leeward face