UNITRACC - Underground Infrastructure Training and Competence Center

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Process description

Mar 16, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Preparatory works

Preparatory works for lining with continuous pipes with annular space

(Image: Cleaning)

(Image: Inspection)

(Image: Damages)

Old sewer

Taking out of operation (securing of drainage capability)
Cleaning
Optical inspection
Removal of roots, deposits and other drainage obstacles
Probable sealing of groundwater infiltrations
Measurement and calibration of the section that is to be rehabilitated
Probable creation of an excavation for installation (dependent on process variant and nominal size)

Mar 16, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Preparatory works

Condition acquisition for lining with continuous pipes with annular space

(Image: Inspection)

The following aspects are to be considered during inspection:

Deviations in the inner diameter
Direction changes
Displaced joint
Laterals
Ground water infiltrations
Flow obstacles
Deformations
Cracks, fragments, break

Mar 16, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Preparatory works

Condition acquisition for lining with continuous pipes with annular space

Obstacle elimination

Pipe reductions, expansions or slight direction changes are obstacles that do not necessarily impede the installation of a lining pipe or put the operating safety at risk. The contracting parties have to agree on whether a correction is needed or not [RSV3].

(Image: Determining the minimum cross section with inflatable calibration measuring apparatus)

Calibration

For the correct use of lining processes, it is necessary to obtain …

Mar 16, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Preparatory works

Mar 16, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Excavations for pulling-in the continuous pipe

(Image: Conventional sliplining process with annular space [FI-Teerb] - View of the pulling-in excavation with continuous pipe)

(Image: Bursting of the to be replaced pipeline and simultaneous pulling-in of the HD-PE continuous pipe - view into the insertion pit (Grundoburst process))

Mar 16, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Excavation preparation for pulling-in a continuous pipes

(Image: Attention!) The length of the pulling-in excavation is determined by the permissible pipe bending radii.
If a plastic pipe is bent, the outer fibres of the outside pipe are strained. When the pipe is pulled-in, it is additionally strained by the tensile strength.	(Image: Loads of outer fibres of the continuous pipe when pulled in)

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Excavation dimensioning according to Zimmermann

(Image: Calculating the dimensions of the pulling-in excavation with elastic fixation [Zimme91] - Freely bent continuous pipe with elastic fixation)

(Image: Calculating the dimensions of the pulling-in excavation with elastic fixation [Zimme91] - Continuous pipe with elasitc fixation at sewer)

The dimensions of the pulling-in excavation are calculated as follows [Zimme91] :

Length of the pulling-in excavation of the non-raised, force-inserted continuous …

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Excavation dimensioning according to Zimmermann

(Image: Calculating the dimensions of the pulling-in excavation - Bending curve of the continuous pipe raised by the amount H [Zimme91])

Generally it is recommended, in order to shorten the pulling-in excavation, to lift the continuous pipe by the dimension H above ground level with the aid of roller blocks or stands.

In this way the required excavation length is reduced to the dimension lG2 :

l_G2 = âˆš3HR [mm]

Length of the pulling-in excavation …

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Excavation dimensioning

(Image: Excavation for the bilateral pulling-in of a continuous pipe)

If a road bed of the whole length of the excavation is dug out, the excavation can be pulled-in in two directions.

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Permissible bending radii

(Image: Attention!)

If the pulling-in procedure is interrupted for a longer period, the continuous pipe has to be secured in the pulling-in excavation so that the bending radii do not fall below the maximum permissible bending radii.

Mar 16, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Excavation preparation

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Principle of procedure

(Image: Conventional sliplining process with annular space with reference to [FI-Teerb] - Depiction of principle [Image: S&P GmbH])

In this process, a correspondingly long, flexible continuous pipe of HD-PE with a circular cross section is pulled from an excavation into the pipe sector to be rehabilitated in one operation with the help of a winch . The remaining annular space between the liner and the inner wall of the sewer is grouted.

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Application areas

(Image: Limiting conditions)

(Table: Application areas of the conventional lining with continuous pipes [FI-Steina])

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Necessary tensile force

Tensile force is necessary for the pulling-in of lining-pipes.

(Formula: Calculation of the tensile force for pulling-in a continuous pipe)

(Image: Tensile force F and gradient reference to [Koch85] [FI-Hoech] [Image: S&P GmbH])

The necessary tensile force is determined by the following factors:

the weight of the continuous pipe (q_R [N/mm²]*l [mm]),
the coefficient of friction of the ground (Î¼) and
the ascending or downward slope of the old line (…

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Permissible tensile stress for conventional lining with continuous pipes

(Image: Tensile stress with reference to [FI-Hoech] [Koch85] [Image: S&P GmbH])

(Formula: Tensile stress)

The tensile force F with the cross section A creates the tensile stress , which must be smaller than the permissible tensile strength Ïƒ_tension,perm.

The permissible stress depends on

the ambient temperature,
the duration of the pulling-in process and
the permissible extension of the pipe.

(Image: Attention!)

Only winches with tensile stress …

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Permissible tensile force

(Table: Maximum permissible tensile forces for pipes made of PE 80 at pipe-wall temperatures of 20 °C (40 °C), rounded values [DVGWGW320-1])

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Permissible tensile force

(Table: Maximum permissible tensile forces for pipes made of PE 100 at pipe-wall temperatures of 20 °C (40 °C), rounded values [DVGWGW320-1])

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Maximum pulling-in length

(Formula: Maximum permissible length that can be pulled-in)

For HD-PE-pipes (PE 80), the following maximum pulling-in length can be obtained Â– independent of pipe diameter and wall thickness Â– given that the permissible strain is 2% for lines with an ascending slope of up to 10°:

680 m at 20°C
the pulling-in length reduces to 425 m when continuous pipes are heated to 40°C in the summer

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Pulling-in of the continuous pipe

(Image: Conventional sliplining process with annular space with reference to [FI-Teerb] [Image: S&P GmbH] - Design of pulling heads for pipes DN 140 to DN 1200)

The forces are transferred from the tension head to the pipe either by means of

a welded connection (with a welded-on insertion cone) or
a flanged connection with weld-on flange or
bolts [FI-Hoech].

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Pulling head connections

(Image: Pulling head with pin connection - external view)	(Image: Pull head with pin connection with reference to [FI-Hoech] [Koch85] [Image: S&P GmbH])
(Image: Pulling head with pin connection - internal view)

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Limiting conditions

(Image: Temperature)

Very important when working with HD-PE pipes are alterations in length due to changes in temperature, which, especially on hot summer days, can lead to problems.

In order to avoid this, the slip linings should be inserted in the early hours of the morning, as the temperature of the material and the ambient temperature in the section of the sewer to be rehabilitated are nearly equal at this time [Vogt90].

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Practical examples

(Image: Lining with continuous pipes – pulling-in excavation [FI-KMG])	(Image: Lining with continuous pipes [FI-KMG] - Heating element butt welding)
(Image: Lining with continuous pipes – target excavation [FI-KMG])

Mar 23, 2006

Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space

Practical examples

(Image: Conventional sliplining process with annular space [FI-Teerb] - View of the pulling-in excavation with continuous pipe)

(Image: Conventional sliplining process with annular space [FI-Teerb] - Pulling-in opening provided with slides to protect the pipe run)

(Image: Conventional sliplining process with annular space [FI-Teerb] - Welding of HD-PE pipes outside the excavation with the heating element butt-welding process)

(Image: Conventional …

Mar 23, 2006