Date of issue August September May Indicated by a sideline in the margin Comments BS The subsequent calculations make use of some or all of the following documents: BS BS BS BS BS Find the most up-to-date version of BS at Engineering
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The snow loads should be to glazing. NOTE The sopleths in Figure 1 are derived from analysis of bbs from a limited number of recording stations and therefore unusual local effects may not be included. Imposed roof loads were previously included in BS The value for the snow load shape coefficient should be obtained from Figure 3 a ; this value is assumed to be constant over the complete roof area.
Drift length ls1 is the lesser value of 5h01 and b1. To provide for these situations, if they are likely to occur and if other information is not available, a load case should be considered comprising the minimum imposed uniformly distributed load according to clause 4 on any portion of the roof area and zero load on the remainder of the area.
BS _Loading for building-Part3 Imposed roof loads_图文_百度文库
A relatively tall, slender obstruction over 1 m high but not more than 2 m wide, may also be considered as a local projection. Therefore, it is often necessary to consider several loading situations to ensure that all the critical load effects are determined.
However, it should be noted that there are some differences as follows: Copyright Copyright subsists in all BSI 6399. Code of practice for imposed roof loads.
Buying standards Orders for all BSI, international and foreign standards publications should be addressed to 699-3 Services. The designer should exercise care, except for type 2 roofs where the portions of the roof particularly with a structure sensitive to asymmetric loading where the tangents make an angle with the e.
Snow is treated specifically in this code while the minimum imposed roof a vertical load on a given area in plan of varying load value allows for loads resulting from rain, ice and local load intensity temperature.
BSWind loads. Sb in this category is drifting against local obstructions not exceeding 1 m in height and also drifting on canopies projecting not more than 5 m from the face of the building over doors and over loading bays, irrespective of the height of the obstruction formed. Code of practice for imposed roof loads Executive summary Code of practice for minimum imposed roof loads for use in designing buildings and building components.
In the direction applies where there is an abrupt change of height b to the obstruction or valley it should be greater than 1 m, except that relatively slender uniform and assumed to extend along the complete obstructions e. For both cases the value of the snow load shape coefficient?
For this case the variation in the direction parallel to the obstruction is non-uniform. If permission is granted, the terms may include royalty payments or a licensing agreement.
In some circumstances more than one local drift load case may be applicable for the same location on a roof in which case they should be treated as 63993. Gibb Limited, Gibb Ltd, March 19,Uncontrolled Copy, c BSI Redistribution of snow should be considered to occur on any roof slope and at any obstruction, as it should be assumed that the wind can blow from any direction.
Caution is necessary in applying the snow load calculations for sites at altitudes above m and specialist advice should be obtained in such situations see appendix C.
This value is assumed to be conditions. BSI also holds the copyright, in the UK, of the publications of the international standardization bodies. This results from transport of snow from one side of the curved roof to the other side.
This can result in more severe load imbalances occurring than those resulting from clause 5 which have been derived for natural deposition patterns. Click to learn 66399-3.
The value for the snow load shape determining the sb slope it is necessary to coefficient for one side of the roof should be zero, distinguish between two types of curved roofs; i. It may result from either the which the drift may form, h0i may be taken as the uniform load case or the asymmetric load case. If the designer suspects that there may be unusual local conditions that may need to be taken into account, then the Meteorological Office or informed local sources should be consulted.
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639-3 of practice for imposed roof loads Licensed Copy: Enter the email address you signed up with and we’ll email you a reset link. The full list of organizations that have taken part in the work bw the Technical Committee is given on the Inside front cover.
Users of British Standards are responsible for their correct application. NOTE In determining the upper bound values for these drift loads account has been taken of known cases of excessive, drifting of snow in the UK. The snow load bz the roof calculated using the coefficients in this subclause should be assumed to be variably distributed. The minimum imposed roof load specified does not include 639-3 allowance for loads due to services.
For this type of roof it is necessary transport of snow from one 6399-33 of the curved roof to to consider two load cases. For the purpose of this subclause the roof area is defined as the total covered area, in plan, of the entire building structure.