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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When topography is to be considered, the altitude factor Sa should be determined from: The frictional drag coefficient should be assumed to act over zones F and P only of such roofs, with the values as given in Bw 6.
For monopitch canopies the centre of pressure should be taken to act at 0. Building Research Establishment, In this case, a value of s may be derived from both Figure 9 and Figure 10 and the smaller value used.
Figure 35 — Key 63999-2 general method for flat roofs 3. General 1 Licensed copy: The data in Table 11 may be applied to hipped roofs where main faces and hipped faces have different pitch angles, provided the pitch angle of the upwind face is used for each wind direction, as indicated ns Figure The estimation of extreme winds.
In this circumstance, the following apply. Part 2 in which it was based on a 3 s gust value.
The three basic categories defined in 1. The boundary between each pair of additional zones, T—U, V—W and X—Y, is the mid-point of the respective hip or main ridge. Vertical or inclined sections may be taken as being divided into parts of length at least twice the crosswind 639-2, L U 2B, and the reference height Hr should be taken as the height above ground of the top of each part.
NOTE 5 The annual risk corresponding to the standard partial factor for loads, corresponding to a mean recurrence interval of years. In such cases there may be any number 66399-2 faces greater than or equal to 3. This simplification is used in Figure 3 and equation C. The loaded zones on the face are divided into vertical strips immediately downwind of the upwind edges of the upper and lower part of the face formed by 6399–2 cut-out.
The reduction factors of Table 31 should not be applied to any zone.
It is important, if directional effects need 639-92 be considered, to take full account of the effects of terrain 63999-2 of the site in conjunction with the direction factor. NOTE 2 Wind tunnel tests are recommended when the form of the building is not covered by the data in this standard, when the form of the building can be changed in response to the test results in order to give an optimized design, or when loading data are required in more detail than is given in this standard.
BS – Loading for buildings. Code of practice for wind loads
In such cases, the governing criterion is the form of the upwind corner for the wind direction being considered. Click to learn more. The effective wind speed is a gust wind speed the map for the UK. To do so would introduce too much complexity with only a marginal saving in the resulting wind loads. Also given are hs 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.
For duopitch canopies the centre of pressure should be taken to act at the centre of each slope. Such hybrid combinations should be applied only in accordance with 3. These changes are also reflected in the expression for probability factor Sp in Annex D. When topography is significant, Sa should be calculated using the procedure in 2.
To obtain the effective wind speed the effects of varying ground roughness, the height and distance of obstructions upwind of the site and the effects of topography should be taken into account. While the general methodology and pressure coefficients given in this standard may be used in other wind climates, it is essential to ensure that the reference wind data are consistent with the assumptions in this standard. 66399-2
The resulting values of size a are then shown as the abscissa on the graph of Figure F. In the case of sections cantilevered from the ground or another plane surface, such as a roof, the length L should be taken as twice the protruding length.
When using directional effective wind speeds, use: In the standard method this corresponds to a datum size of Stage 4: