4. Introduction
Circular sewer pipe which are manufactured in factories
are joined after placing in proper position. This type of
joint depends on the material of pipe, external load,
internal pressure types of support and so many other
factor.
5. The following are the requirements of good sewer joints
1. It should be economical and easy in construction
2. It should be water tight and highly resistant to infiltration of
ground water and exfiltration of the sewage
3. It should be resistant to sewage gases and acids
4. It should be non-absorbent and should not absorb anything
5. It should be durable and have long life
6. It should be easily available in required quantity
7. It should not be easily broken or cracked by traffic
6. Bandage joints
This joints is mostly used for concrete pipes. At the
end of the pipes. A hollow is scooped out 25mm
deep,75mm under and 75mm ahead. This hollow is filled
with mortar to invert of the trench. Now netting is placed
on the mortar and scrim is placed on the netting. The face
of the pipe at the end are coated with mortar and butted
against each other now netting is tightly wrapped around
the pipe and the strands are hooked securely together.
Squeezing the mortar firmly on the pipes.
7.
8. Spigot and socket joint
This joint is used mainly for C.I. pipe of all sizes and
concrete pipes below 60cm. Spigot and socket joint are following
type
1. Rigid joint
2. Flexible joint
Semi-flexible type spigot and socket joint is composed of
specially shaped spigot and socket end of concrete pipe. A rubber
ring placed on the spigot which is forced into the socket of the
pipe previously laid . This compress the rubber ring as it rolls into
the annular spaced formed between the two surface of the spigot
and socket and forms a flexible and water tight joint
9.
10. Collar joints
Collar joints are following type
1. Rigid type collar joint
2. Semi flexible collar joint
11. 1. Rigid type collar joint
This is generally used for pipes over the 60cm dia
and for light hydraulic pressure. Collars are 15cm 20cm wide
caulking space varies from 1.3 to 2cm according to the diameter of
pipes. Caulking material is slightly dampened mix of cement and
sand rammed with caulking irons.
12. 2. Semi flexible type collar joint
This is generally used for the large diameter hydraulic
pipes the loose collar twin specially shaped pipes. Rubber rings
are provided on each end which when compressed between the
spigot and collar. Seals the joint
13.
14. Flush joint
flush joint is generally used for sever passing below the
culverts. Flush joint are following type.
1. Internal flush joint
2. External flush joint
1. Internal flush joint
the ends of the pipe are specially shaped to from a self-
centering joint with an internal jointing space of 1.3cm wide.
The finished joint flush with both inside and outside with the
pipe wall. Cement mortar is used for filling the jointing space
15. 2. External flush joint
This joint is suitable for pipe which to small for jointing
from inside. Great care should be taken in handling to ensure
that the projecting ends are not damaged as no repair can
readily from inside the pipe.
16.
17. Mechanical joint
In this type of joint, the mechanical devices such as flanged
rings, bolts, etc. are used to keep the two ends of sewer together
such type of joint is generally used for metallic sewers such as
cast-iron, steel, etc.
18. Filled joint
In this type of joint, the cement mortar of proportion 1:1 or
1:2 is inspired between the space bell and spigot end. In under
to maintain the alignment of sewers, the gasket or packing
pieces may be placed the mortar is filled in the annular space
formed between bell and spigot ends and the joint is finished
by applying cement mortar at an angle of about 45°on the outer
face.
the cement mortar joints are widely used in the
construction of sewers and they are found to be satisfactory.