Design & Testing
Plastic Pipes Conference Association # 1998 Gothenburg
Alferink, Janson, Olliff
Extensive field trials are being performed in a project sponsored by TEPPFA and APME,to obtain well documented information about the behaviour of buried thermoplastics pipes. as outlined in the paper by Alferink, Bjorklund and Kallioinen (Ref 1). This information is of vital importance to obtain a workable design method for buried pipes. Tests were carried out using different pipe materials (PVC,PE,Steel), different pipe stiffness, buried at depths varying between 1.15 and 3 metres, using clay as well as sand as sidefill, and by installing them in a compacted as well as in a dumped way. Pipe detlection and strain measurements were carried out, when the pipes were loaded by soil, traffic and internal hydrostatic pressure. European design experts were put to work with the soil and pipe parameters, and asked to carry out the design using their own or their national design method. Afterwards, they were provided with the results of the measurements carried out on the pipe as well as on the soil, allowing them to asses their design. Then in December 1997 a workshop took place with those experts to discuss the results and with the intention to obtain a good basis for establishing an unified design method for all buried pipes, and by that assisting current CEN work on the same subject. This paper presents a first glance of the results of the work carried out so far. The results show that consistency between installation and design practice is one of the major factors to be considered. Based on the results as found in the field studies, the authors recommend a design approach which safely predicts the behaviour of buried pipes.
Related papers
Author(s) : Anders Andtbacka, Frans Alferink, Peter Sejersen
The behavior of buried plastic pipes is already well described in standards and technical specifications and as well as proven in real life conditions. Plastics pipes in diameters up to around 400 mm are already in use for more than 60 years and pipes with larger diameters for more than 20 years now. All with good...
Author(s) : Frans Alferink
PVC pipes for buried applications for water, sewer and gas, has developed an excellent track record. PVC is very inert, has a high resistance against permeation of soil contaminations and gas components and meanwhile has a long proven lifetime. Next to that, the lifecycle costs of buried PVC pipe systems are amongst...
Author(s) : André Nijland, Frans Alferink
PVC-U is used around the globe for potable water supply and sewer applications. This is due to its strength and stiffness as well as to its excellent flow properties. PVC-U shows an excellent performance in protecting the potable water quality. And it is registered that failure rates of PVCU pipelines are very low....
Author(s) : Frans Alferink and Jos Oosterik
PVC-O pipes were already introduced in the mid-seventies, but why did it take until the beginning of this century before this high quality pipe product really expanded successfully into the water markets? The second part of this paper will present an answer to that question. Feedback from various pipe markets around...
Author(s) : Alferink
Plastics pipes products are more and more appreciated in sewer schemes throughout the world. The advantages of thermoplastics, like the good resistance against sewer environments and the possibility to built complete tight systems are many times the drivers to use thermoplastic pipes and chambers. Plastics chambers...
Author(s) : Hojer, Janson, Oderkerk, Venator
For nearly three decades two technology processes have been available for production of PEX piping by moisture induced silane crosslinking (PEX-b). The first technology, the Sioplas™ process, was invented and patented by Dow Corning. This process requires extruding pipe from a reactive compound composed of silane...
Author(s) : Bassewitz, Janson, Liebel
From Jan 6th 2001 until March 31st 2005 a research project, funded by the German Ministry for Economy and Research had been carried out in order to investigate technical details not yet researched. The results of the project have shown that polymer flexible pipes for district heating are fit for purpose. The research...
Author(s) : Janson, Alferink, Wolters
This paper presents the results of work that was performed at the request of TEPPFA , The European Plastics Pipes and Fittings Association, on the issue of “Combined loading” (external and internal loading) of buried thermoplastics pressure pipes. The work is of great importance for users and designers of...
Author(s) : Janson, Bergstroem, Baeckman, Blomster
When performing strength quality control of PE pressure pipes made of new grades it is important to take the creep vs. time into consideration and not only the common stress vs. time behaviour. Thus, it is just the relation between linear strain and logarithmic time, which will within a reasonable testing time help...
Author(s) : Alferink
When starting with the application of buried thermoplastics pipes in the fifties, Wavin started to gain a lot of experimental experience with these pipes, which later formed a solid base for the correct application of thermoplastics pipes. In analogy, a lot of experimental experience is gained now with buried manholes...
Author(s) : Alferink
Two papers dealing with the intermediate results of the TEPPFA / APME project on design of thermoplastics pipes has been published at the 10th Plastics Pipes Conference in Gothenburg in 1998 by Alferink et al.1, 2 Meanwhile the study has been almost completed and the results discussed with several experts. Pipe...
Author(s) : Olliff, Rolfe, Wijeyesekera, Reginold
Soil-pipe interaction studies generally recognise the significance of deformations in the pipe due to soil loading, but not differential ground and structure movements, which can induce excessive stress concentrations in the pipeline. Plastics pipes can suffer failure due to such movements, though their flexibility...
Author(s) : Janson
Sustainable Development’ is a concept which is often used today, particularly when discussing necessary efforts for preventing persistent environmental problems. It came up as a result of the findings already by the Rome Club et al in the early 70s’, implying that the natural resources of the earth are limited and in...
Author(s) : Alferink, Bjoerklund, Kallioinen
Over the last 15 years several attempts have been undertaken to establish a design method for plastics pipes (IS0 TC138 WG13) and over the last ten years to establish an unified design method for all buried pipes (CEN TC1641165 JWGI). Several national methods are available and it is shown over the last ten years that...
Author(s) : Janson
At the International Conference on Plastics Pipes W in Bath 1988, a paper was presented by the Author called : "Physical ageing of buried PVC sewer pipes as affecting their long-term behaviour". The tests performed on constantly deflected pipes referred to at that time had been running for approximately one year....
Author(s) : Alferink, Guldback, Grootook
Wavin gained a lot of experience with operational PVC sewer pipes by monitoring installations and measuring pipe deflections over a period of about 35 years, as reflected in the database "PiPer". Some of the oldest pipes have been measured and dug up now to study the durability of these pipes. Furthermore the results...
Author(s) : Alferink, Wolters
Results of deformation measurements carried out on buried plastics pipes installed at six different tests sites are discussed in this paper. The results show that the deflection of buried pipes is usually rather small and the time dependence is limited to a few years after installation. Traffic loading does not result...
Author(s) : Janson
New research and development particularly concerning the long-term strain of modern PE resins have created a basis for a simple and adequate method for tightness testing of plastics pressure pipelines. Thus, it is shown that for plastics pipes subjected to constant internal hydraulic pressure, it is quite possible to...
Author(s) : Alferink, Wolters
Knowledge about the behaviour of buried flexible pipes has become more and more important in the Netherlands. It serves several objectives, for instance, to evaluate stress corrosion, installation techniques and new materials, as well as drawing up new design codes and test procedures for pipes and components. This...
Author(s) : Janson
The investigation has indicated that deflected uPVC pipes are subjected to a physical aging process, which gives rise to a lower rate of decrease in the E-modulus than has previously been assumed. Based upon these findings the long term ring stiffness of PVC sewer pipes is determined. Concerning the bending strength...
Members of the Association
