tunnel's - Trenchless International

projects
HDD under
the Havel River
By Lutz Rau
SEE US AT
70
BOOTH NO.
When crews in Germany installed a pipe 17 m below ground in a limited-size area with strict angle
requirements, pipe-by-pipe assembly using Duktus DN700 ductile iron pipe allowed for high installation
rates, despite project constraints.
Berlin’s Havel River, measuring over
a kilometre in width, supports a series of
water wells on its banks. Berlin’s water
supply company, Berliner Wasserbetriebe,
pumps raw water from the Schildhorn Wells
and treats it in the Tiefwerder Waterworks,
producing drinkable water.
For the past three years the wells have
been under renovation. Open trench
excavation was utilised to replace a 2 km
section of raw water pipeline with ductile
iron pipes.
Fighting the slope
In a sloping region of Charlottenburg,
486 m of the pipeline runs approximately
17 m below the high river bank.
Because of this severe project constraint,
open-trench installation was immediately
dismissed, and the project proponent had
to consider alternative means of renovating
the ageing pipe.
The existing pipes lay in relatively short
lengths of 6 m, and had restrained joints
with angular deflections. Horizontal direction
drilling (HDD) was chosen as the preferred
technique as it provided an elegant way of
meeting these difficult requirements.
Instruction by the pipe supplier’s applications engineering department.
The installation crew quickly
gained momentum with
the drilling and installation
process, and the 486 m long
pipeline was assembled and
pulled in in just 34 hours.
Working with ductile iron
An order was placed for 504 m of Duktus
ductile iron pipes to EN 545 with TYTON
push-in sockets with BLS/VRS-T restraint
systems and associated fittings. This type
of pipe is lined with cement mortar and has
an outside zinc coating with a rugged outer
cement mortar coating of EN 15 542. This
coating can withstand very high mechanical
and chemical stresses.
The installation
The existing bore was enlarged to
850 mm, and then bored out to 1,100 mm.
TAKING CARE OF THE ENVIRONMENT!
Ductile iron pipe systems for trenchless laying.
Visit us at the No-Dig 2012 in São Paulo, pavilion F, stand 70
and at www.duktus.com
The steel assembly ramp – a shrink-on sleeve and protective cone being fitted.
The installation crew quickly gained
momentum with the drilling and installation
process, and the 486 m long pipeline was
assembled and pulled in in just 34 hours. In
this time frame the crews also managed to
finish installing joint protection, which had
been planned to take up to 60 hours.
projects
October 2012 - Trenchless International
Because of this severe
project constraint, opentrench
installation was
immediately dismissed, and
the project proponent had to
consider alternative means of
renovating the ageing pipe.
Fitting the traction head.
October 2012 - Trenchless International
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