Purchase your copy of BS as a PDF download or hard copy directly from the official BSI Shop. All BSI British Standards available. The use of BS part 2:wind loads, for design of temporary structures (English ) Wind loading: a practical guide to BS , wind loads on buildings. PROFESSIONAL. Welcome. IP51S0LUTIONS. Thank you and welcome to ‘ BS Wind Loading – Practical Design, an IStructE seminar presented by.
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Similar percentage changes would apply for different sizes and heights. Strong winds in the atmospheric boundary layer. NOTE 2 For sites in towns less than 0. This general method also accounts for the variations in high local suction around the periphery of the roof caused by various bss forms of eaves detail.
The reduction factors of Table 31 should be used for upwind eaves and verge zones A to D and H to J, with the parapet height h determined at the upwind corner of each respective zone. In this case, a value be s may be derived from Figure 9a and Figure 9b and Figure 10a and Figure 10b, and the smaller value used.
Determines the effective wind speeds required by Stage 3: Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. Vertical or inclined sections may be taken as being divided into parts of length 6399-22 least twice the crosswind breadth, L U 2B, and the reference height Hr should be taken as the height above ground of the top of each part.
Before any reduction in wind speeds is considered specialist advice should be sought. In this circumstance, the following apply.
When topography is to be considered, the altitude factor Sa should be determined from: NOTE For all sites inside towns except exactly at the upwind edge or at a distance of 2 km from the upwind edge the simplifications of the standard method produce a larger value of Sb than the directional method.
The shape of the roof in Figure 35 represents a typical arbitrary roof plan. Ridge zones on all other downwind faces should be excluded. NOTE 1 The annual mode, corresponding to the most likely annual maximum value. The terrain and building factor Sb should be determined from 3. This applies to the sea, but also to inland lakes which are large enough and close enough to affect the wind speed at the site. If these details are to be used for any other purpose than implementation then the prior BSI written permission of BSI must be obtained.
For monopitch canopies the centre of pressure should be taken to act at 0. NOTE In the directional method, topographic effects are determined separately from altitude effects. British Constructional Steelwork Association Ltd. The value of the site wind speed Vs should be obtained from the relevant meteorological authority. When considering low rise buildings which are close to other tall buildings the rules for effective height will not necessarily lead to conservative values and specialist advice should be sought.
BS Loading for buildings. Part 2 Wind loads | José García –
Also given are tables which have been derived directly from the equations which will be useful as an accuracy check to those wishing to implement the equations into computer software.
The displacement height Hd is given by: It is important, if directional effects need to be considered, to take full account of the effects of terrain upwind of the site in conjunction with the direction factor. This shows the stages of the standard method, together with the relevant clause numbers, as the boxes outlined and connected by thick lines. The definitions of loaded zones and pitch angles are given in Figure General 1 Licensed copy: Electronic books The e-book database EBC.
Where the upwind edge of the wall is flush, or inset a distance of less than 0. NOTE Instead of calculating the crosswind breadth B and inwind depth D for the complex building plan, these dimensions may be determined from the smallest rectangle or circle which encloses the plan shape of the upwind wing or of the whole building, respectively.
For any part vs the roof that is above the top of the parapet, i. However, due to contributions from other sectors, the overall risk will be greater than the required value. NOTE 3 Bx figures in this table have been derived from reference . Kh and Kb are parameters depending on the building height and location and on the form of construction of the building see C.
However, the value of ns gust factor in terms of the gust period t is not of direct application to design. However, the reference height Hr is taken as the actual height of the top of the wall above ground.
NOTE 5 The annual risk corresponding to the standard partial factor for loads, corresponding to a mean recurrence interval of years. In practice, option b will not produce significantly lower values than a unless the combination of location, exposure and topography of the site is unusual.
Buying standards Orders for all BSI, international and foreign standards publications should be addressed bw Customer Services. NOTE 3 Where both positive and negative values are given, both values should be considered. Over a smooth surface such as open country the wind speed is higher near the ground than over a rougher surface such as a town.
The reference height Hr is the height above ground of the ridge. For porous walls and fences with solidity less than 0.
The equation for this family of curves is: This gives further confidence that the year period of the original analysis was representative. The scaling length b is 3699-2 from the height H and crosswind breadth B of the windward face. Directional method 3 Licensed copy: The resulting frictional forces should be applied in accordance with 3.
External pressure coefficients are given in 2.