Alferink
Non-Pressure Pipes Systems # 2001 Munich
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 installation turned out to be the most important parameter, and contrary to many design methods, burial depth and traffic load is not a real issue for buried flexible pipes. Based on these results, physics of pipes buried in soils were discussed. This was followed by some additional work, with the aim to further back up the results and try to find and propose improvements for the existing design approaches. The work consisted of a few extra field tests and several model tests. Some of these model tests have been performed first in 1999 and were discussed with the European design experts in a workshop. Based on these discussions more sophisticated tests have been performed and extensively documented. This paper shows part of the results and explains that the soil-pipe interaction process is primarily a volume process in case of flexible pipes. It illustrates the mistake that will be made when geometrical non-linearity is included in load steered methods for flexible pipes and the soil changes are neglected. Finally it proposes a model that can be applied to all existing theories and that will better reflect the actual performance of flexible pipes. Furthermore, it also gives some recommendations for the design of the more rigid pipes. Finally it advocates the use of simple transparent and understandable design methods, as these give by far the most reliable results.
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) : 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) : 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, 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...
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) : 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) : 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) : Alferink, Blom, Venema, Wolters
Joints in PE casings of district heating pipelines are made by extrusion welding, butt welding or sleeves in which sealing is obtained by an adhesive. To set up guidelines for making these joints a lot of research has been performed, part of which is described in this paper. Joints of a good quality are obtained if...
Author(s) : Alferink
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