AGRU HDPE pipe used to support trunk sewer upgrades at Three Mile Creek
In 2018 , Mobile , Alabama , began a project to upgrade an existing 36 ’’ and 42 ’’ trunk sewer into a new 11,000 ft , 60 ’’ diameter gravity trunk sewer main . The upgrade would involve a segment of the pipe that starts on the south side of Three Mile Creek before crossing over ending at a Severe Weather Attenuation Tank . The upgrade was essential to provide the needed transmission and storage capacity to reduce the occurrence of sanitary sewer overflows during rain events .
The proposed upgrades posed design challenges due to the size of the pipe and structures . Additionally , project site constraints limited the length of installed pipe and reduced the available working space .
To overcome installation constraints , engineers utilized two sizes of AGRU HDPE pipe , which provided enough flexibility to allow the contractor to complete the installation while also managing the site constraints . HDD was the installation method .
Additionally , because the existing pipe segments had a limited diameter , the engineer designed a solution that utilized sections of 48 ” and 63 ” diameter pipes in SDR 11 . AGRU was the only manufacturer that could provide products that met this requirement .
The contractor successfully installed the pipes . Furthermore , the engineering team ’ s choice of piping product and installation approach has provided time savings as the alternative would have been tunneling under the creek . Once completed , this project will become the largest diameter HDPE HDD project in North America .