Finite element analysis of long-term performance of buried high density polyethylene pipes

Buried pipes are utilized for various applications such as sewers, water conveyance, and highway drainage systems. Advantages such as lightweight, ease of installation, low cost, higher impact strength and durability have resulted in the extensive use of High Density Polyethylene (HDPE) pipes during the past few years. Time dependent properties such as creep associated with HDPE material may reduce the expected design life of high density polyethylene pipes under field conditions. The objective of this research work was to investigate the time dependent nature of buried high density polyethylene pipes using the finite element analysis. The influence of trench width on the performance of 24 inch (600 mm) and 48 inch (1200 mm) single-wall and double-wall corrugated pipes under different loading conditions were also investigated. Pipes buried up to a depth of 60 feet were considered. Results show approximately 60 to 80% of the creep deformation within one year of the pipe installation. Pipe deformations observed over 50 years were not more than 30% of the initial pipe deformations. Finite element results also show that 24 inch (600 mm) and 48 inch (1200 mm) HDPE pipes can be buried successfully at depths up to 20 feet by using a trench width ratio as low as 1.5