Comparison of Liner Design Codes in Europe and Abroad

Abstract

The actual German design code DWA-A 143-2:2015 differentiates between four Host Pipe States: State I (sewer untight; no cracks), State II (sewers with longitudinal cracks; soil pipe system stable), State III (cracked sewer with large deformations; considerable risk to failure in the near future) and State IIIa (sewer no longer existent as it is totally corroded or cracked to pieces). In some foreign standards (e.g. ASTM F 1216 and EPS 203) two states are defined: Sewer structurally safe (intact pipe) or fully deteriorated (deteriorated pipe). The paper reports about common aspects and differences between different codes. a) The background of State I and II (intact pipe condition) is the liner in the host pipe subjected to water pressure, described either by an unsupported pipe applying a support factor K > 1 or by a rigidly bedded pipe applying reduction factors for different imperfection. b) The background of State III and IIIa (deteriorated pipe condition) is the liner, described either by a bedded liner-pipe-soil system or an elastically bedded pipe. Experimental results are helpful to get insight into the failure modes of stability and/or break and to create a basis for appropriate imperfections. New imperfection tables are presented in the code DWA-A 143-2 to regard different liner products that fail elastic and/or non-elastic. Some aspects of grouted liners are pointed out.

Techniques