STRUCTURAL DESIGN OF BURIED CORRUGATED POLYETHYLENE PIPES

Abstract

Test sections of corrugated polyethylene pipe (CPEP) were buried, as in typical drainage installation, in competent, compacted, granular backfill. Both dead load (soil cover) and surface live load (truck dual wheels) were applied. The objectives of the tests were to (a) observe performance of the pipes under load, (b) identify performance limits, (c) resolve some of the questions unanswered by present design methods, and (d) propose improved methods for the structural design of buried CPEP. The objectives were achieved. Experimenters agreed that tests confirmed the complementary interaction of pipe and backfill. Minimum soil cover was investigated under multiple passes of live loads. Conditions for structural stability of the pipe were identified. An analytical procedure was developed for predicting the minimum height of soil cover to assure ring stability under multiple passes of live loads. Maximum soil cover tests confirmed the ring compression analysis as the primary basis for design but also revealed a need to include the effects of ring deflection. An observable performance limit was identified, and a method of design was developed that combined the effect of ring deflection and ring compression on the performance limits of CPEP buried under maximum height of soil cover.