Rehabilitation using GRP, PE, PVC, and PP segment pipes

Segmental pipe sliplining consists in the introduction of short pipe segments into a host pipeline. Depending on the type of rehabilitated network and pipeline, the lining is slipped in through existing manholes or dug out pits.
The lining segments reflect the shape of the host pipeline: thus, they can be circular or non-circular.

TECHNICAL EVALUATION OF THE SEWER

Before the rehabilitation the pipe is jet-cleaned with a sewer cleaning machine placed on a truck. After that the pipeline is inspected with a remote-controlled camera. The analysis of the video from the sewer inspection forms the basis to create a detailed computer report on the technical condition of the pipe. On the basis of report data a specific sewer is classified.

SELECTING THE REHABILITATION METHOD

Depending on how the sewer is damaged or destroyed and its classification to a specific group, an appropriate rehabilitation method is selected. After the evaluation of the sewer’s technical condition one should analyze geodetic data, groundwater level with respect to the base of the sewer, road traffic exposure, and other ratios that have influence on the selection of parameters of the liner that is to be used.

STORAGE AND TRANSPORTATION TO THE CONSTRUCTION SITE

The segmental pipe liner is delivered to a stacking yard and from there it is delivered to the construction site in appropriate batches.

Individual lining segments are slipped inside the rehabilitated sewer through existing manholes (for segments up to 0.5 m and diameter up to DN 600 mm) or through an installation pit whose dimensions fit the size of the segments, using a crane with a carrying capacity matching the weight of the segment.
Following that, manually, using a slide or appropriate carriage, the segments are moved to the assembly place. The segments are connected using seals placed in pipe sockets. The new pipeline should be aligned centrally, along the host sewer’s axis.
Rehabilitation lining segments shorter than 500 mm can be joined using manual devices. Larger segments should be joined using levers, manual hoists, or presses. During the process segment surfaces in the area where the connection is made should be protected against damage. Force must not be applied to any point of the spigot segment end.
Before the connection, one should check the required depth of inserting the spigot end into the socket, and mark it around the pipe end. Only a full insertion of the spigot segment end into the socket ensures a secure and tight connection. As the sealing elements in the sockets are subject to high pressure forces the joining should be made using mechanical devices.
Before the connection each segment should be appropriately prepared by cleaning, drying, and degreasing both the socket and spigot on which the seal is inserted. If glued connections are made the adhesive must be applied with an appropriate tool, e.g. brush, while any excess should be wiped off with a cloth or scraper.
The response time depends on the type of adhesive and ambient temperature. The adhesive manufacturer’s instructions should be observed at all times.

CONNECTING A HOUSE DRAIN – FOR MAN-ACCESSIBLE SEWERS
At the place of connecting the house drain to the segment pipe lining, holes should be made with a pneumatic hole saw, and then openings of an appropriate diameter should be cut out in the house drain using a pneumatic jigsaw. Then:
– create a packer of a length of 1000 mm in the house drain,
– connect the packer with the segment pipe by way of lamination.
Surfaces to be laminated should be dry, degreased, and free of dirt. Such work should be performed at an ambient temperature of at least 10°C and air humidity under 70% (ventilation using sewer fans should be used to obtain such conditions).

GROUTING
Grouting is carried out in n-stages, in the sections between manholes. In the downstream manhole the space between the host pipe and the segment pipe should be sealed; at levels 1/n; 1/n +1/n;… control tubes should be installed, while the stub for feeding the grout should be installed at the topmost point. At the topmost point in the seal of the upstream manhole a venting pipe must be installed to allow free escape of air, and a stub through which grouting will be fed.
Grout must be fed at such a pressure so as not to exceed permissible buckling pressure i.e. so that the pipe does not collapse. This is crucial during rehabilitation of large diameter sewers with low circumferential rigidity. Use struts inside the segment lining while filling the space between the pipes to ensure the segment lining does not deform due to the pressure exerted by the grout.

CCTV INSPECTION

Once the installation is finished and house drains are opened a CCTV acceptance inspection is made and recorded on a DVD or another storage medium. At the same time an inspection report is prepared.

TESTS

In accordance with PN-EN ISO 11296-1, PN-EN 13566-5, and PN-EN 1610

Any defects are made good with the help of a camera-controlled robot and/or by patching with short sections of the pipe liner.