Jacking Pipes to Enlarge Sewer Main

Several floods proved that the capacity of the DN 1250 concrete sewer main of Doetinchen was not sufficient during heavy rainfalls. The municipality of Doetinchem therefore decided to insert a second main for a 304 m section next to the existing sewer. Since the existing pipe had to remain in service parallel to the new line and due to various other obstacles in the residential area, trenchless construction was found the best solution. Soil conditions – sand and medium to coarse gravel – would have made the drainage of ground water and sheet pilings necessary if the sewer would be constructed by open trench. This and to prevent disturbances to residents and traffic disruptions were further matters of consideration for the municipality. It was up to the engineering company Witteveen and Bos to choose an adequate material for the job and the unique attributes of HOBAS CC-GRP Jacking Pipes that are ideally and inherently suited for trenchless installation methods convinced them. The comparably light wall construction of HOBAS Products proved to be advantageous for the limited space on site. Their smooth outer surface creates little friction allowing lower jacking forces and their long service life were the main convincing factors in their decision making process.