Alternative Pipe Material Choice Provides Trenchless Solution: Fid-Bau Portal

Alternative Pipe Material Choice Provides Trenchless Solution

Vandaelle, Craig / LeBlanc, Jeffrey

This is a case study presented on the Big Lake (W14) Gravity Sewer Microtunneling Project in Edmonton, Alberta. The gravity sanitary sewer project was designed as a direct bury application with PVC and RCP pipe. It was expected that the subsurface conditions were to vary considerably within the proposed depth of proposed pipeline. The subsurface conditions within the pipe zone were expected to include water bearing peat, fill, and saturated silt and silty sand, all of which were extremely soft, with blow counts as low as 2. To address these conditions, the design included special bedding and embedment envelops to ensure the installed pipe is adequately supported to prevent pipe settlement and structural failure of the pipe. This design component was more essential to the longevity of the PVC Pipe than the Concrete Pipe. As an alternative, Michels Pipeline proposed to install the pipe by means of microtunneling in lieu of direct bury. In addition they proposed the use of fiberglass jacking pipe for this installation method. The project construction began utilizing 48” diameter FRP jacking pipe, but due to the unfavorable subsurface soil conditions the project was not able to be completed with this pipe material. As a solution to the installation difficulties, the pipe material was changed to 48” FRP Lined Reinforced Concrete Jacking Pipe. This is the first installation of FRP Lined Reinforced Concrete Jacking Pipe in North America.