Sewer Rehabilitation in all Sizes and Shapes for Krakow’s old Sewer System

In 2007, the city council put rehabilitation of 5 km of sewer pipes under 13 roads out to tender. The concrete pipes dated back to 1900-1945 and showed considerable damage: leaks and cracks put the surrounding soil at risk and as most of the pipelines run under heavy traffic routes, the structural load capacity of the sewers also had to be ensured. A consortium PBG – INFRA – PBRSP Kielce won the contract to replace the pipes with a cross section of 800/1200 mm through 3000/2520 mm. Not only could the contractors draw on the very good experience they had already had with HOBAS Products, but also support and technical advice from the HOBAS Experts, particularly regarding the many special sections. Several special profiles were custom made to fit the sewers. The wall thicknesses of these sections were determined to WRc regulations. Installation work then began in May 2008. To rehabilitate the oval sewers, HOBAS NC Sections 1710/1810 mm were produced in three different lengths: 2.35 m long pipes were used in the straight parts and 0.5 – 1 m long ones in the curved parts. The sections were pushed into the old sewer from prepared entry shafts, joined and fixed in place to prevent them from floating or bending while the cement grouting was pumped in. The annulus be-tween the old sewer and HOBAS Profile was carefully filled in stages.