BS 6399-3 PDF
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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Depending upon the pattern being considered the snow load on the roof should be treated either as a uniformly distributed load or as a variably distributed load over all or part of the roof. NOTE However, where, for example, on a lower roof area sheltered from all wind directions, there is the possibility of redistribution of snow from a higher roof to form a local drift on top of a uniform snow load distribution on this lower roof, it would be appropriate to consider the local drift load acting in combination with the uniform snow load on the lower roof.
No loads incidental to maintenance are appropriate to glazing. For this case, the local drift from 7. 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.
The designer should be aware that the deposition and redistribution of snow on roofs are very complex phenomena.
If permission is granted, the terms may include royalty payments bd a licensing agreement. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover.
Drift length ls1 is the lesser bbs of 5h01 and b1. These include local shelter from the wind, which may result in increased local snow loads, and local configurations in mountainous areas, which may funnel the snow and 639-3 increased local loading. The appropriate snow load shape coefficient at the face of the obstruction and the drift length should be obtained from Figure 9 or the following in which all parameters are as defined in Figure 9.
The type and record length of the ground snow data available and the paucity of observational data on roof snow loads make it extremely difficult to estimate snow load distributions reliably.
For this type of roof it is necessary complete roof, e. It should be the most onerous value arising than 2 m wide, may also be considered as a local from uniformly distributed snow on the roof slope projection. This will be indicated in the amendment table on the inside front cover. The values for the snow load shape coefficients are assumed to be constant in the direction parallel to the eaves.
Enter the email address you signed up with and we’ll email you a reset link. These are flat, monopitch, pitched or surrounding roofs or obstructions. Several snow load cases may have to be considered in design to check adequately for the different snow load patterns that can occur.
In general, load cases should be considered to act 7. Ensure use of the most current version of this document by searching British Standards Online at bsonline. The value for the snow load shape determining the equivalent slope it is necessary to coefficient for one side of the roof should be zero, distinguish between two types of curved roofs; i.
The correction is based on limited information which shows that the snow density is increased when the snow forms in drifts.
However, it should be noted that there are some differences as follows: General 1 Scope This Part of BS gives minimum imposed roof loads for use in designing buildings and building components which are to be constructed and used in the UK and the Channel Islands. For parapets, see 7. This value is assumed to be conditions. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services.
This can be caused by following symbols apply. May Replaced By: It should be assumed to act vertically and refer height of the building.
BS _Loading for building-Part3 Imposed roof loads_图文_百度文库
In some circumstances more than one of the load cases will be applicable for the same location on the roof. The value for the snow load shape coefficient for the other slope should be obtained from Figure 3 b ; this value is assumed to be constant over the loaded slope of the roof.
In the direction parallel to the obstruction or valley it should be uniform and assumed to extend along the complete length of the obstruction or valley, except where stated otherwise. This value is assumed to be constant over the complete roof area. The type and record length of the ground snow data available and the paucity of observational data on roof snow loads make it extremely difficult to estimate snow load distributions reliably. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained.
To determine the uniform and asymmetric snow load cases, these structures may be divided into the single-span basic elements considered in 7. It presents the UK view on standards in Europe and at the international level. Table 1 — Values of salt for 6 Snow load on the ground corresponding values of sb 6.
NOTE However, where, for example, on a lower roof area sheltered from all wind directions, there is the possibility of The value vs the snow load shape coefficient for the redistribution of snow from a higher roof to form a local drift on other slope should be obtained from Figure 3 b ; this top of a uniform snow load distribution on this lower roof, it value is assumed to be constant over the loaded would be appropriate to consider the local drift load acting in combination with the uniform snow load on the lower roof.
For sites whose altitude is above m specialist advice should be sought see clause 1 and appendix C. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Users of British Standards are responsible for their correct application.
For both cases the value the other side. The snow load on the roof calculated using the coefficients in this subclause should be assumed to be variably distributed.
BSLoading for buildings. This British Standard applies to: Included in this category is drifting 6399–3 in metres ; against local obstructions not exceeding 1 m in height and also drifting on canopies projecting not a is the angle of pitch of the roof measured from more than 5 m from the face of the building over the horizontal.
The correction is based on Snow is naturally deposited in many different limited information which shows that the snow density is patterns on a roof depending upon the wind speed, increased 63999-3 the snow forms in drifts.
The bss should be aware that the deposition and redistribution of snow on roofs are very complex phenomena. The recommendations of this clause may also be used where a ladder is permanently fixed to allow access to a roof for cleaning and maintenance only.