Large profiled plastic pipes: practical experience and test concepts
May 08, 2007
Besides the so-called classic materials concrete, reinforced concrete, vitrified clay and cast iron, plastic products are increasingly used for the construction, renewal and renovation of drains and sewers. Numerous surveys, research projects and product tests by the IKT - Institute for Underground Infrastructure (Gelsenkirchen, Germany) have dealt with the behaviour of single products under practical and laboratory conditions (cf. [1], [2], [3], [4]). Special emphasis was put on the rehabilitation of sewers, the investigation of special applications, the influence of quality as well as the determination of demands on the dimensioning and testing of pipes and construction methods.
For the new construction of drains and sewers, pipes of various materials are offered. Besides pipes made of concrete, reinforced concrete, vitrified clay and cast iron also plastic pipes are increasingly used. If the information by the DWA [6] is taken as a basis, between 2001 and 2004 the proportion of plastic pipes in the German sewer system has grown from around 3 % to around 6 %. In the range of nominal diameters ≥ ND 800 (large pipes) the proportion of plastic pipelines amounts to around 1 %.
To determine the actual state of plastic pipelines, which have already been installed, with regards to possible precarious features sewer inspections were carried out and inspection videos of non-accessible sections were sifted. In connection with the inspection of passages with large profiled pipes, 24 sections with a total length of around 1.5 km were inspected and additionally, the cross sections were comprehensively measured. The videos viewed contained TV inspections of altogether 248 sections with a total length of around 10 km. Weak points, cases of damage (such as leaks, for example) or other peculiarities that were found were identified as well as pictured and described. In the following substantial precarious features in the area of pipes, pipe joints, side inlets, manholes and manhole constructions are compiled.
- condition assessment in situ
- deformation of the cross section
- influence from operation loads
- (time-dependent) stability collapse
- local external loads (point loads).
DWA standard A 127 (cf. [12]) classifies pipes as flexible if, due to their deformation, the surrounding soil is part of the bearing system. Correspondingly, to verify long-term deformations a vertical change of diameter of 6 % (or 9 % when looking at additional verification) is permitted. Also regarding the effects of extreme deformations on the functional safety and water tightness, special importance is attached to assessing pipe deformations. Starting from the current state of experience with deformation measuring data, a method for acquiring and analysing deformation measuring data has been developed, which can be summarized as follows:
- Measuring is carried out by employing a telescopic measuring stick, by means of which the internal pipe diameter is measured in regular intervals or locations with precarious features in the horizontal and vertical direction (cf. Figure 5).
- The measuring data is processed and is recorded graphically (cf. Figure 6). Here, the horizontally and vertically measured diameter values are plotted on the y-axis; the stations are to be taken from the x-axis.
- A permissible deformation range (DR) is chosen, e.g. from the regulations in [12] or from the static calculation (DR = 2 x permissible δV), and is inserted into the diagram by means of two horizontal lines. Since the actual diameter of the undeformed pipe does not have to correspond to the target diameter according to the manufacturer, the deformation range is oriented at the mean value of all measuring values by especially taking into account extreme deformations (cf. [4]).
- Spots with extraordinary deformations or figures are identified as critical pipe cross sections for further observation and are correspondingly marked in the analysis of the measuring data. With regards to a possible long-term stability collapse in future inspections these cross sections should generally be assessed in detail and should be checked for possible changes or increase of deformation.
Basically, the stability behaviour of large pipes can also be determined by large-scale experiments of the scale 1:1. However these experiments, under hydrostatic external pressure at the IKT large-scale experimental rig, for example, hardly seem economically efficient. Usually a mathematical stability proof is advisable when verifying the calculation model by small-scale model experiments. A corresponding concept was developed by the IKT and the University of Applied Sciences in Münster (field of statics and constructional computing).
Against the background of the practical experience, laboratory tests and mathematical analyses the following conclusion can be drawn for practice:
Bibliography
[1] Bosseler, B.; Kaltenhäuser, G.: IKT-Warentest – Hausanschluss-Liner; final report of the IKT - Institute for Undergorund Infrastructure (November 2005), download on www.ikt.de.
[2] Bosseler, B.; Liebscher, M.: Erneuerung mit dem Berstverfahren: Bemessung, Prüfung und Qualitätssicherung von Abwasserrohren; final report of the IKT - Institute for Underground Infrastructure by order of the Ministry for Environment and Nature Protection, Agriculture and Consumer Protection of NRW (November 2003).
[3] Bosseler, B.; Schlüter, M.: Qualitätseinflüsse Schlauchliner; Stichproben-Untersuchung an sanierten Abwasserkanälen; final report of the IKT - Institute for Underground Infrastructure by order of the Ministry for Environment and Nature Protection, Agriculture and Consumer Protection of NRW (December 2003), download on www.ikt.de.
[4] Bosseler, B.: Beitrag zur Darstellung, Analyse und Interpretation von Verformungsmessdaten aus der Inneninspektion biegeweicher Abwasserleitungen. Technisch-wissenschaftliche Berichte, IKT-Bericht 97/4 (June 1997).
[5] Bosseler, B.; Sokoll, O.: Profilierte Großrohre aus Kunststoff - Praxiserfahrungen und Prüfkonzepte; final report of the IKT - Institute for Underground Infrastructure by order of the Ministry for Environment and Nature Protection, Agriculture and Consumer Protection of NRW (Oktober 2005).
[6] Berger, C.; Lohaus, J.: Zustand der Kanalisation, Ergebnisse der DWA-Umfrage 2004; KA -Abwasser, Abfall (2005), Issue 5, pp. 528-539.
[7] Company information bauku - Troisdorfer Bau- und Kunststoff GmbH, Wiehl-Drabenderhöhe.
[8] Company information Frank & Krah Wickelrohr GmbH, Schutzbach.
[9] Company information Henze GmbH, Troisdorf.
[10] Regulations of the Deutschen Vereinigung für Wasserwirtschaft, Abwasser und Abfall e.V. (DWA), Standard A 127: Statische Berechnung von Abwasserkanälen und -leitungen, 3rd edition, Hennef, GFA (August 2000).
[11] Falter, B.; Holthoff, F.: Statiken für profilierte Rohre; Report of the Münster University of Applied Sciences / Department of civil engineering by order of the IKT - Institute for Underground infrastructure; Münster (November 2004, unpublished).
[12] Regulations of the Deutschen Vereinigung für Wasserwirtschaft, Abwasser und Abfall e.V. (DWA), Standard A 127: Statische Berechnung von Abwasserkanälen und -leitungen, 3rd edition, Hennef, GFA (August 2000).
[13] Falter, B.; Holthoff, F.: FEM-Berechnungen zum Beulverhalten von außen profilierten Rohren der Nennweite DN 300; Report of the Münster University of Applied Sciences / Department of civil engineering by order of the IKT - Institute for Underground infrastructure; Münster (September 2004, unpublished).
[14] Falter, B.; Holthoff, F.: FEM-Berechnungen zum Beulverhalten von profilierten Rohren der Nennweite DN 2000; Report of the Münster University of Applied Sciences / Department of civil engineering by order of the IKT - Institute for Underground Infrastructure; Münster (September 2004, unpublished).
More News and Articles
Apr 26, 2024
News
Bothar’s cutting head innovation
The trenchless industry in Australia continues to grow and the need to provide customised solutions becomes vital for a leading subsurface contractor.
Recognising the need for advanced solutions to meet the growing …
Apr 24, 2024
News
Sustainable drainage solutions: German Start-up transforms urban water management.
Germany boasts a well-established infrastructure for managing rainwater and wastewater, yet many developing countries lack such systems. Addressing this gap, …
Apr 22, 2024
News
HDD tooling that gets the job done
Horizontal directional drilling is a dynamic process that constantly changes and adapts to suit a range of applications across utilities and infrastructure. Operators looking to get the most from their equipment …
Apr 19, 2024
News
WATCH: Overnight with SAERTEX-LINER H20 in São Paulo
Available through Pipe Core, high-quality liner SAERTEX-LINER H20 performed under pressure in São Paulo, Brazil.
Maintaining aging potable water pipe infrastructure is a constant challenge …
Apr 17, 2024
News
Immersive media provides wastewater experience in Denmark
An immersive media experience (IMX) may not be what most people want when they think about industrial wastewater, but that is exactly what visitors can expect when they visit a new installation …
Apr 15, 2024
News
Spotlight on gender diversity at Pipe Core
Since founding in 2008, Pipe Core’s team has grown across all areas of the business and is now in a position where there are more females than males across the organisation. Research published in Harvard …
Apr 12, 2024
News
New Wave of Startups Scale Innovation to Solve Global Water Challenges
Innovators from Around the World Join Xylem’s 2024 Accelerator Program to Deploy Breakthrough Innovations for Utilities and Industrial Users of Water
A new group of startups …
Apr 08, 2024
News
Integrated sustainable electricity and clean drinking water systems
Altitude Water and New Use Energy Solutions have partnered to create integrated, mobile solar-plus-water generation systems that produce sustainable electricity and clean drinking …
Apr 05, 2024
News
How to Evaluate Hydraulic Fracture Risk in HDD Design
The design of horizontal directional drill (HDD) installations often requires an evaluation of the potential for hydraulic fracture of the soil layers through which an HDD passes. Evaluating …
Apr 02, 2024
News
Historic Project Linking Rome and Vatican City Uses Advanced Technology and Local Knowledge to Keep Water Flowing
Relocation of Major Sewer Infrastructure Enables Construction of Pedestrian Link for 35 Million Visitors to the 2025 Jubilee
Water …
Mar 27, 2024
News
USU Study Looks at Water Main Break Rates in the U.S. and Canada
Report Highlights Correlation Between Material and Diameter
Utah State University (USU) has published new research on water main breaks in the United States and Canada, examining …
Mar 26, 2024
News
Update BE-21: New Material in Course and Modules on Trenchless Pipe Installation
Online training on the topic of pipeline installation in civil engineering: Trenchless technology for underground drainage construction can be a resource-efficient, …
Contact
IKT - Institut für Unterirdische Infrastruktur gemeinnützige GmbH
45886 Gelsenkirchen
Phone:
0209 17806-0
Fax:
0209 17806-88