Main Differences in the Static Calculation Methodology for Flexible Pipes 1. INTRODUCTION 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.e. Between the method given by the ATV A127 standard ('Guidelines for Static Calculations on Drainage Conduits and Pipelines') and the method established by the American Water Works Association (AWWA) more specifically in its manual M55 ('PE Pipe Design and Installation'). BRIEF REVIEW ABOUT THE RELATED METHODOLOGIES The ATV A127 is a standard of German origin and its latest version dates from the year 2000. It is widely used in Europe and its content exclusively covers the methodology for calculations of all kinds of pipes. AWWA M55 is not a standard, but rather a design manual according to the recommendations of the American Water Works Association (AWWA) covering all relevant aspects of the design and installation of HDPE pipes.

• Awwa M55

HDPE Potable Water Industry Standards: AWWA, ASTM, CSA, NSF. AWWA M55: Manual for the Design and Installation of Polyethylene Pipe in water. Awwa Manuals of Water Supply Practices Set - Download as Word Doc (.doc /.docx). M55 PE PIPE—DESIGN AND INSTALLATION This manual describes the.

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 to the AWWA manuals of other types of pipes). The methodology basis used in this manual is the most used, almost exclusively, in the Americas. COMPARISON 3.1. BASIC DIFFERENCES IN THE METHODOLOGY OF CALCULATION For the main basic differences between both documents, it can be mentioned:. The ATV A127 methodology aims to be universal, i.e. For any kind of pipe, regardless of the material or its status as 'rigid' or 'flexible'.

Awwa M55

The AWWA M55 methodology, on the other hand, stands exclusively for the case of flexible pipes. Soil load calculation is more conservative in AWWA, due to the fact that this manual does not consider, as ATV does, the “arc” effect that usually takes place for flexible pipes (reducing the weight of the soil prism right above the pipe).

Another important difference is the way in which each methodology analyses the distribution of the filling soil load around the pipe. Both methodologies are based on the theory of M.G.

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 A127 ATV standard does take into account the influence of this horizontal active pressure. The ATV methodology is much more detailed regarding trench-pipe interaction and does a deeper analysis about the intervention of each of the variables.