Designing Installations with High Density Polyethylene: Open Cut Construction

High density polyethylene (HDPE) pipe is increasing in popularity for installation in municipal water and wastewater systems. HDPE has been widely used for trenchless technology installations, such as horizontal directional drill (HDD), pipe bursting, and sliplining. Installation of HDPE through traditional open cut construction is increasing as municipal use of the material continues to grow. Pipe installation references provide typical design parameters as to which extensive design analysis is not required. Some installations fall outside of these parameters, and this paper will highlight areas of installation as to which the designer should perform the detailed analysis. This paper will provide detailed information on calculating important design installation equations. Project examples calculating wall buckling and compressive stress, pipe deflection, allowable external pressure for unconstrained pipe, allowable tensile stress during trenchless pull-ins, and more. Available references providing detailed information on calculations and installation procedures will be provided. Actual project examples will be provided in order to help the audience translate the analysis from equations to field installation conditions. While the focus on the paper is HDPE, the presentation of unique installation conditions requiring additional pipe installation calculations would be useful for any pipe material and engineering analysis.