PE Pipe – Design and Installation MANUAL OF WATER SUPPLY PRACTICES M55, First Edition AWWA MANUAL M55 First Edition American Water Works. AWWA M PE Pipe – Design and Installation. Document Language: English; Published By: American Water Works Association (AWWA); Page Count: Find the most up-to-date version of AWWA M55 at Engineering
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AWWA methodology verification for long term buckling in the presence of groundwater was also defining in most cases, but without reaching the magnitudes of ring stiffness of ATV. The influence of groundwater, especially for long term buckling verification, probed to be very important in the ATV, resulting pipes of a very high ring stiffness for big cover depths in the presence of groundwater pressures.
In each case the most appropriate Krah pipe the one that verified all conditions was selected and its ring stiffness was registered, observing the following: However, these considerations are not taken into account by AWWA at any time.
– ATV A Standard vs. AWWA M55 manual
However, what should be the choice of one or another methodology for calculating is the accuracy of each in terms of its correlation with reality. Another important difference is the way in which each methodology analyses the distribution of the filling soil load around the pipe.
Generally this is because of the differences in the treatment of buckling verification between both methodologies. wawa
The ATV A methodology is more conservative when coming to the treatment of the “long term” analysis, especially in the case of thermoplastic materials, as it considers that the pipe will be permanently loaded in time and, therefore, it has to be always verified for every long term load using the materials long term properties creep module, ultimate stresses.
The methodology basis used in this manual is the most used, almost exclusively, in the Americas. The ATV methodology is much more detailed regarding trench-pipe interaction and does a deeper analysis about the intervention of each of the variables.
It is widely used in Europe and its content exclusively covers the methodology for calculations of all kinds of pipes. While AWWA methodology does not distinguish between vertical or sloping trench walls, in the ATV methodology the inclination angle of the walls of the trench is an important variable.
This is based on zwwa theory that, if the pipe behaves like flexible and it is well installed i. In the figure below an example can be seen of the obtained results i.
When applying each method in performing static calculations of pipes, the following differences can be observed: The ATV A methodology aims to be universal, i. In the ATV the use of sheet piling or coatings to contain the walls of the trench, and its removal methodology once installed the trench fill, acquires importance.
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However, while the M55 AWWA manual takes this theory without modification assuming, as Spangler, that no horizontal active pressure will develop on the pipe, the A ATV standard does take into account the influence of this horizontal active pressure.
On the other hand, AWWA requires less and easier to estimate data. Both methodologies are based on the theory of M. The purpose of this article is to set up the main differences between two popular methods worldwide for performing static verifications of HDPE flexible pipes, i.
This does not happen in AWWA, where, despite the fact that the bedding angle is actually considered, its real influence on the final results is very low.
The main difference in the trench scheme that analyzes each methodology is based on the consideration of awww different zones of ground: The recommended methodology of structural calculation is one of the ten chapters that the manual contains and is exclusive for HDPE pipes although the guidelines are common aww the AWWA manuals of other types of pipes. However, what can be analyzed are the results that occur in one or another case. For the main basic differences between both documents, it can be mentioned: