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Unformatted text preview: s plus beam
e) Transport and
unloading 5.3.3 Core Thickness
The core thickness shall not be less than the design
thickness by more than 5 percent. The manufacturer
shall declare the core thickness and the above tolerance
shall be applicable to that core thickness. Permissible Stresses
2.5 N/mm* for
upto and including pipe dia
600 mm and
1.0 N/mmz for
600 mm. 0.56fi0s o.5~ ().34fik0”5 0.5 fik 0.67 N/mmz 0.5fi
().56 fik0”5 O. S&k Characteristic compressive strength of
concrete at p days in N/mm*, and
strength of concrete in N/mm*. 6 JOINT DIMENSIONS
Joint dimensions with tolerances for socket and spigot
,., i ” IS 784:2001
1 Longitudinal stresses induced in the core during circumferential prestressing shall be treated as temporary and shall be equal
to 0.284 times initial compressive stress induced in core.
2 Forlongitudinal tressdue to beam action, a pipe shall be
assumed to span its full Iengtb and suppost a total load per meter
in Newtons equal to the self weight, the weight of the water in the
pipe and earth load equivalent to 2.2 times the outside diameter
of pipe (in r@.
3 For calculation of number of Iongitudinalsfor tnmsport and unloadingconditiorw followingbendingmoment shallbe considered
foreffectivelengthofpipcs upto 5mcterand dismctcrupto600mrw
250 Description of Loading
Combination e) Operating condition + Live load
(with impact) 3.04X 10’
3.78 x 107 0.45 &k 1 The total tensile stress in the core shall be consideredas the sum
of the hoop stress and flexrmdstresses, without the application of
any reduction factor.
2 When calculating hoop stress, only core thickness should be
cmrsidemd. When calculating ovalization flexw.alstress,the sum
of the core and coating thickness should be considered.
3 For calculating bending moments and thrusts forextemal loads,
Olandm’scoefficientsareto be used.The valuesforbidding angles
from 30” to 180° are given in AnnexE.
4 When submitted to factory test, the mortar or concrete coated
pipe shall not have cracks in the coating wider than 0.1 mm for
more than 300 mm length. 7.4.2 Typical calculation for the design of longitudinal
for pipe diameter 600 mm and below is given in
7.4.3 Circumferential Prestressing Requirements
The permissible stresses for various load combinations
shall be as given below: 7.5 Loss of prestress in circumferential and longitudinal wires shall be calculated as per Annex F.
7.6 Typical design of prestressed concrete pipe, with
winding by process of counter weightheak is given
in Annex G. Permissible Stresses
o a) Circumferential
(Self weight +
b) Site test condition
(Site test pressure +
Self weight +
Weight of water +
Earth fill + Final
c) Factory test condition...
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- Fall '13