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A DN 500 trunk water main
Zweckverband Gruppenwasserwerk Dieburg
supply utility – Southern trunk water main
from Hergershausen to Gross-Zimmern
by Heinz-Jörg Weimer
1 Introduction
The Zweckverband Gruppenwasserwerk
Dieburg utility supplies water to more than
120,000 people in the region. The water is distributed
to customers through its pipeline network
of around 1,000 km via trunk mains, local
mains and house connection pipes. Of this total
of around 1,000 km, the Zweckverband replaces
about 2 % a year with the latest generation of
ductile iron pipes.
2 Planning
In the southern part of its distribution network,
the renovation of a difficult section had been put
off in the past because of the demanding technical
requirements. Along a very short stretch, the
pipeline crossing below an important section
of German Federal Railways (DB) track and a
federal highway similar to an autobahn needed
to be replaced. The existing protective casing
tubes could not be used because the supply of
drinking water had to be maintained throughout
the whole of the replacement phase.
3 Description of the route
The site of the replacement operation was on
the south-eastern edge of the Dieburg group
of municipalities. At this point, the route runs
along the Altheimer Strasse for about 385 m
in a north-south direction between the Darmstadt-Aschaffenburg
railway line and a valveequipped
manhole containing a needle valve
which is situated on district road K 128.
The route to be followed by the new pipeline
due for installation began on the northern side
of the Darmstadt-Aschaffenburg railway line
48
Fig. 1:
Path followed by the route
and crossed below it. It then continued for a
length of 30 m along the foot of the embankment
carrying federal highway B 45 and then crossed
below it (Fig. 1). Where it continued, there was
a DN 1500 overflow sewer below which a crossing
had to be made by culvert.
4 Crossings below
DN 900 protective casing tubes were installed by
steered pipe jacking for the crossings below the
railway embankment and federal highway B 45
(Fig. 2). The lengths of the stretches of casing
tube were 20 m (to cross the railway embankment)
and 65 m (to cross the federal highway).
Retained seepage water and an intersecting gas
pipeline allowed only slight variations in height
(Fig. 3). The jacking of the tubes having been
completed, the ductile iron pipes were pulled in
(Figs. 4 and 5).
FGR® / EADIPS® 46