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南非土木工程施工标准 L部分 屋顶 英文原文节选 20100079 3-12 |
GENERAL
The regulations contained in Part L of the National Building Regulations shall
be deemed to be satisfied where -
(a) any roof or rooflceiling assembly is the subject of a rational design in accordance
with the requirements contained in Parts B and C and such roof
or rooflceiling assembly complies with deemed-to-satisfy rules contained
in provision LL4 and LL5 of this Part; or
(b) the construction of any roof contemplated in provision LL2 complies with
the requirements contained in that rule.
EMPIRICAL RULES FOR THE CONSTRUCTION OF ROOFS
Where any roof is to be supported on the walls of any building, contemplated
in rule KK2 of this code, such roof shall be constructed in accordance with
rules LL3, LL4 and LL5.
CONSTRUCTION AND FIXING OF STRUCTURAL ROOF COMPONENTS
The location and dimensions of any part of any roof shall be such that the minimum
height requirements contained in Part C are satisfied.
Roof timbers shall comply with the requirements of the relevant of SABS 563,
SABS 653, SABS 876, SABS 1089 or SABS 1245. ~
SABS 0400-1990 86
1
LL3.3 The requirements of subrules LL3.4 and LL3.5 shall apply only to single or double
pitched Howe-type trusses, with a span of not more than 10 m, supported at
heel joints only and having bays of equal lengths of not more than 1,5 m .
2 3
LL3.4 (a) Where the roof covering is of the class given in column 1 of Table 1 the
size of rafter (top chord), tie-beam (bottom chord) and the grade of timber
to be used shall be selected from such table in such a way that the desired
truss span does not exceed the relevant figure for maximum truss span
given in column 4, 5 or 6, as the case may be.
(b) All web members shall be not less than 38 mm x 114 mm Grade 4 timber.
(c) Where rafter and tie-beam sizes are to be determined from Table 1, the
slope of the roof shall -
(i) be not less than 1 5 O nor more than 30° for Class A or Class C covering;
and
(ii) be not less than 17O nor more than 35O for Class B covering.原件下载： 
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