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Unformatted text preview: ices, each splice shall be thoroughly
visually checked by twisting the ring through 360°.
Splices showing visible separation or cracks shall be
rejected. Not more than two splices in each ring shall
be permitted. All sealing rings shall be protectt?d from
direct rays of the sun and stored in dry place. 5.3.2 Internal Diameter
For pipes of length less than 4 m, the tolerance shall
be *5 mm for diameter upto and including 350 mm.
For diameter above 350 mm, the tolerance shall be
2 .. . IS 784:2001 diameters shall be furnished by the manufacturer for
inspection. The indicative dimensions of socket and
spigot are given in Annex B. For pipes of length 4 m and above, the tolerance shall
be as given below:
Tolerances Internal Diameter 7 DESIGN A
% / Up to 900 mm
Over 900 mm and
upto 1 600 mm
Over 1600 mm In areas within
600 mm c)fan
end of the pipe
*6 Over rest
of the pipe +9 in Annex C.
7.2 All pipes shall be designed to withstand the combined effects of internal water pressure and external loads. mm
* 12 + 12 7.1 Information to be supplied by purchaser is given + 12 7.3 The design of the prestressed concrete pipes shall
cover all such stages, which may induce stresses in
any section of the pipe. For investigation of these design stages, the likely extreme conditions of stresses
shall be considered in the order of their occurrence,
during the process of manufacture, handling, erection
and under service. Table 1 Nominal Internal Diameter and
Minimum Core Thickness of Pipes (Clause 5.1)
mm Nomianl Internal
mm (1) (2) (3)
1300 7.4 Design
2500 Criteria for Non-Cylinder Pressure The pipes shall be designed to meet the requirements
given in subsequent clauses.
7.4.1 Longitudinal Prestressing Requirements 75
85 The permissible stresses for various load combinations
shall be as follows:
Description of Loading
130 a) Longitudinal
losses) in barrel NOTES
I Internal diameter of pipes other than those mentioned in this
table may be suppliedby mutualagreementbetween the purchaser
and the manufacturer.For higherpressure the core thickness have
to be increase~ in such cases:
a) the diameter will be correspondingly reduced (This is to
enable use of same moulds), and
b) multiple layers of circumferential prestressing wire shall be
2 This standardincludesprovisionupto 2500 mm diameterpipes.
Pipes of diameter beyond 2500 mm maybe supplied in special
cases by mutual agreement between purchaser and manufacturer
subject to additional precautions taken in design, manufacture,
testing and construction of the pipe. b) Longitudinal
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This document was uploaded on 10/01/2013.
- Fall '13