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南非土木工程施工标准 LC:电缆导管 英文原文节选 20100079 1-28 |
CONCRETE ENCASEMENT. Where so required, ducts shall be encased in concrete in accordance with the
requirements of the project specification.
LAYING OF CABLES WITH OTHEK SEKVICES. Where one or more cables are to be laid in a trench containing
other services, the Contractor shall lay the cable duct(s) along one side of the trench with the other
services occupying the other side but, before comnencing excavation for such a trench, the Contractor
s h a l l , unless the requirements are given in the project s p e c i f i c a t i o n , or on the drawings, or in the
schedule, obtain from the Engineer instructions on whether the requirements of 5.1.1 and 5.7 and the
requirements of Subclauses 5.4 and 8.2.3 of SABS 1200 DB are applicable, or whether some other
requirement is applicable to the trench width.
CROSSINGS OF TELEPHONE AND ELECTRICITY CABLE DUCTS.
supply cable ducts, strict precautions and care shall be taken and close supervision given to the
laying of the ducts.
Except where it is acceptably encased, no e l e c t r i c i t y supply cable shall be laid within a distance of
600 mm measured horizontally, nor shall any such cable cross within a distance of 300 mm measured
v e r t i c a l l y . from any telephone cable.
Where an e l e c t r i c i t y supply cable and a telephone duct are laid in a common trench the horizontal
distance between the cable and the duct shall be as directed by the Engineer.
A t each crossing the Contractor shall provide and i n s t a l l an approved type of s p l i t sleeve consisting
of two half-round pipe sections firmly fastened together with robust s t a i n l e s s steel straps. The
sleeve s h a l l extend a t l e a s t 1,0 m on each side of the crossing and shall be effectively sealed a t the
ends.
The material used for the s p l i t sleeve shall be as specified in the project specification.
ROAD CROSSINGS. A t each road crossing a duct or ducts, of size s u f f i c i e n t to receive the cable or
cables t o be laid, shall be i n s t a l l e d under the road. The duct(s) shall be laid to the same line and
level as that a t which the cable(s) are to be l a i d , with due regard for the requirements of minimum
cover under the road. The duct(s) shall extend a distance of a t l e a s t 0,s m beyond each kerb face or
the edge of the road, as applicable.
DUCT ROUTE MARKERS.
d i r e c t i o n , and a t intervals not exceeding 60 m along the s t r a i g h t .
approximately 25 mm above the finished ground level, except where they a r e l i k e l y to cause obstruction
or be i n the way of moving t r a f f i c , in which case the Contractor shall ask the Engineer for instructions
i n t h i s regard.
In addition to marking the route, the Contractor shall submit to the Engineer a record s e t t i n g out the
position of a l l route markers.
POSITION TO BE MARKED.
crossing shall be indicated by the letters "GPO" or "ESC", as applicable, painted by means of an
approved s t e n c i l with red paint on the kerb face d i r e c t l y above the position of the duct.
Where there is no kerb face, as in the case of unconstructed roads, route markers shall be i n s t a l l e d at
such crossings.
REPAIRS AND REINSTATEMENT OF SURFACES.
required in terms of Subclauses 5.9 and 5.10 of SABS 1200 1)B.
TOLERANCES
ALIGNMENT AND GRADE.
ordered, the deviation from a straight l i n e joining the ends of any s t r a i g h t section of ducting shall
not at any point along a duct exceed 35 mm.
MOISTURE CONTENT AND DENSITY.
the actual density shall be nowhere less than the specified density.
TESTING
ACCESS FOR ENGINEER.
necessary, for the inspection and testing of the ducts during manufacture, the Contractor shall arrange
for the Engineer to have free access a t a l l reasonable times to the place where the ducts and other
materials are manufactured.
charge, every f a c i l i t y , including properly calibrated and maintained test apparatus, and a l l labour
required for such inspection and testing (including sampling) and for the marking of the ducts before
delivery.
COMPACTION TESTS.
of the backfilling. I f t h e test r e s u l t s show that the density of the backfill does not comply with the
relevant requirements, the costs of the testing and any reconipaction and r e t e s t i n g t h a t may be ordered
by the Engineer shall be borne by the Contractor.
PROVING.
shall be thoroughly cleaned by twice drawing a cylindrical cleaning brush through each duct, once in
each direction. The ducts shall then be proved by drawing through them a polished hardwood mandrel
having spherical ends and of length 300 mm. The diameter of the mandrel shall be less than the
internal diameter of the duct by
a) 2 nun i n the case of ducts of diameter up to and including 75 mm;
b) 3 mm in the case of ducts of diameter greater than 75 mm.
Wherever telephone cable ducts cross e l e c t r i c i t y
E l e c t r i c i t y supply cable ducts shall cross below telephone cable ducts.
Duct route markers (see 3.4) shall be placed above the cable a t a l l changes of
Duct route markers shall protrude
I f required in terms of the project specification, the position of each duct
Existing paved surfaces shall be repaired and reinstated as
Except where a change of direction or other alignment is shown on the drawings or
The permissible deviation from OMC during f i e l d compaction is 22 %, and
For the purpose of examining and sampling the ducts and other materials and, i f
The Contractor shall also arrange for the manufacturer to supply, free of
The Engineer may order density t e s t s to be carried out to determine the compaction
After the laying of ducts and the backfilling have been completed, the i n t e r i o r of the ducts
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