Kilian successfully repairs complex stream culvert

Special challenge: The box profile

It was clear from the start that this rehabilitation would be complex – simply due to its location. The narrow, trafficked Bachgasse runs through the center of Hemsbach, a town of 12,000 residents in the Rhein-Neckar district. A 150-meter section of the Hemsbach stream, culverted beneath the street, was affected by corrosion and required rehabilitation. But logistics weren’t the only challenge for Kilian Kanalsanierung GmbH from nearby Fürth in the Odenwald, the company commissioned to carry out the work: the box profile, 85 cm high and around 100 cm wide, is crossed at three points by ceiling-mounted utility lines, reducing the cross-section by up to 20%.

In early October, the Kilian team began on-site rehabilitation. For three weeks, the hand-rehabilitation crew handled all liner preparations. In the fifth week, the liner installation crew joined the project.

UV light and peroxide for consistent curing

After reprofiling the culvert and creating access pits, the critical phase of the project began. The plan: to reline the Bach culvert with a minimal-invasive liner flexible enough to adapt to the angular profile and dry-weather channel while also navigating the crossing pipes as smoothly as possible. These crossings were to be covered with custom-made stainless steel plates. To structurally reinforce the culvert, the liner needed to have a particularly high wall thickness (15.4 mm). The team opted for the BB 2.5 Flex liner from Brandenburger Liner, delivered slightly undersized for extra flexibility.

Working closely with application engineers from Brandenburger Inliner, the Kilian team installed the liner in the final week of October over three days—150 meters in total, weighing 15 tons and divided into three sections. Time pressure was intensified not only by the confined workspace but also by the need for precise curing: in addition to UV light, peroxide was used to ensure the thick-walled Flex liner cured quickly, evenly, and without wrinkles. This combination required great finesse and technical know-how. “Coordinating the curing technique with the liner and profile was the most attention-demanding aspect in both planning and implementation,” explains site manager Daniel Steinbrenner.

“We showed that we embrace challenges”

By mid-November, Kilian Kanalsanierung successfully completed the rehabilitation of the culvert under Bachgasse. A total of 150 meters has now been restored—ready for the next 50 years. “This project called for experienced, level-headed team players,” says Steinbrenner. “Its successful completion motivates us to stay open to rehabilitating unconventional profiles or pipe runs using liners.”

Sven Barth, Managing Director of Kilian Kanalsanierung, also sees the project as a success: “With this successfully completed and technically demanding measure, we demonstrated that we’re eager to tackle challenges—because they help us grow as a team.