TPi October 2009

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developmentsproducts &
October 2009 Tube Products International 33
Pressure jacking pipes for sewers
Rehabilitation of potable water pipes
THE municipality of Groningen in the
Netherlands has extended its existing
sewer main, sized DN 1000 and DN 1200.
The gravity sewer main could not
cope with high flow rates, for example
those occurring during heavy rainfall.
To prevent sewage from overflowing
and polluting the environment, the
authorities decided to convert it into a
closed pressure system. With this, and
its extension by 2.4km Hobas CC-GRP
sewer systems, a capacity of 3,000m3 /h
could be achieved, allowing the line to
easily cope with future needs as well as
the connection of a further village.
Since the line crosses a busy part of the
town of Groningen, Hobas proposed the
use of CC-GRP pressure pipe systems,
which can be installed by open as well
as trenchless construction. As Hobas
GRP pressure pipes can be jacked,
local engineers placing an order for the
company’s CC-GRP, worth €1,222,000
for the complete line. This included five
jacking sections with Hobas CC-GRP
jacking pipes DN 1000 to 1500 and
pressure pipes PN 6, DN 1000 and 1600
m DN 1200, as well as flanges, elbows,
reducers and tees with stainless steel
locked joints.
Several obstacles along the pipe route,
such as roads and a channel, were
overcome by microtunnelling. Due to the
requirements of the road authorities, two
jacking sections running beneath the
highway were realised with cover pipes,
which were delivered by Hobas Benelux,
and the Hobas CC-GRP pressure pipes
were consequently inserted. The largest,
THE shortage of clean drinking water is
a worldwide problem. It is claimed that
more than 55% of drinking water never
reaches the home, due to leaking and
run-down supply pipes. This situation
can be solved at low expense, without
digging and without large investment in
costly equipment.
Tube-In, from MultiLining Products, is a
complete system for the rehabilitation
of potable water pipes and pressure
pipes. Pipes are reconditioned by
pulling an armoured polyethylene
with an outer diameter of 1,500mm, was
positioned beneath highway A7.
The three other microtunnelling sections
were implemented using CC-GRP
pressure jacking pipes PN 6 and flush
FWC couplings. These ran beneath a gas
pipeline, several streets and a navigable
channel, where the installation was
conducted in 12m depth. A 275m long
section with CC-GRP pressure jacking
pipes of 1,280mm outer diameter was
jacked in a curve radius of 1,300m. The
contractor installed an intermediate station
that is required for jacking with over
4,000kN. However, due to the smooth and
non-absorbing outer surface of Hobas
pipes the maximal jacking force did not
exceed 1,800kN, and the intermediate
station was never in operation.
Hobas Engineering GmbH – Austria
hose through the leaking water pipe,
extending the life of the pipe.
Tube-In has a wall thickness of 2-3mm
and is constructed of a polyethylene
inside layer, a strong armour layer and
an outside layer of polyethylene. This
construction gives a very strong pipe
with a clean and smooth inner surface.
Tube-In fits most pipe dimensions and
may be installed in lengths up to 500m
(1,640ft). It can be used in pipes with
a pressure up to 20 bar (280 psi), and
The Hobas flush couplings used for jacking S S
are leak tight and facilitate assembly
accurately follows the shape of the old
pipe, even through bends.
The system is installed by using simple
and inexpensive equipment. The pipe
is first cleaned to remove any deposits,
either with a steel scraper or a Polly-
Pig, a cylinder shaped plug that is
pressed through the pipe several times
by means of water or air. Tube-In is
then pulled through the old pipe, and
when water pressure is restored, Tube-
In will inflate and take the shape of the
host pipe.
MultiLining Products ApS – Denmark
Several obstacles along the S S
pipe route, such as roads and
a channel, were overcome by
microtunneling