Predicting Performance of Large-Diameter Buried Flexible Pipes: Learning from Case Histories

Analytical approaches to predicting pipe deflections are based on the predetermined pipe properties, the anticipated soil properties and on the assumption that the specified installation configuration can be met. However, in-place pipe deflections do often deviate from the predicted. This paper summarizes the observations made from more than twenty case histories of entrenched large-diameter flexible high density polyethylene pipes and discusses the effects of construction methods and site conditions on pipe performance. Procedures are also presented on how site conditions and construction methods can be accounted for when using the TAMPIPE (Texas A&M PIPE) method and the Spangler\u27s method. Procedures are given for predicting the variability of pipe deflections in the field. The TAMPIPE method is also shown to be accurate in predicting the long-term deflection of the pipe