• The condition of engineering structures must be checked every three or six years in accordance with a DIN standard.
• During the main inspection of the bank wall of the Inde in Kornelimünster, every part of the structure is examined in detail.
• The engineers also use an underfloor device to reach the highest point of the structure. 

In order to be able to successively view the up to ten meter high bank wall, the engineers drive along the historic gravity wall with an underfloor device. It intercepts the terrain jump between the Napoleonsberg road and the lower-lying Inde in Kornelimünster. Using a hammer, they tap the masonry over a large area, inspect and document hollow areas and loose natural stones in the masonry, and measure the length of cracks in the open masonry joints. The building has been strengthened time and again. Full renovation work is scheduled for next year. Before that, however, a main inspection will be carried out.

The City of Aachen is also responsible for construction within the Kornelimünster through road and is therefore also responsible for maintaining safety and order for the embankment wall along the Inde at Napoleonsberg. Engineering structures, including bridges and culverts, are subject to a general inspection and monitoring obligation. DIN 1076 regulates the obligation to carry out inspections in a cycle of three and six years as well as observations or inspections to ensure the stability, durability and traffic safety of the structures.

As part of the inspection, the entire structure will be inspected using a systematic procedure and any damage found will be assessed according to the criteria of stability, traffic safety and durability. On this day, the embankment wall from Steinkaulplatz to about 20 meters behind the Benediktusplatz pedestrian bridge will be inspected.

Re-examine documented damage

Critical points were already identified during a property-related damage analysis three years ago. As a resulting protective measure, a protective wall was installed in March 2023, as the stability of the brick parapet of the bank wall on Napoleonsberg is at risk. The existing structure can no longer absorb the horizontal loads to be verified from an impact, for example from a vehicle. The protective wall on the footpath is intended to deflect a potentially impacting vehicle.

"Even though we know at this point in time that the embankment wall will be extensively renovated in 2026, we have to fulfil our obligation to inspect it," emphasizes Barbara Siodmok, engineer in the road maintenance and bridge construction department at Aachener Stadtbetrieb. She will be supervising the inspection of the historic embankment wall on this day, which will be carried out by a contracted engineering firm.

During the main inspection, the damage already documented during the previous inspection is critically examined again and it is also documented whether it has progressed any further. "For example, we know that the steel profiles that tie into the retaining wall are showing signs of corrosion and rusting through, causing the masonry to loosen. This corrosion is so advanced that the cross-section of the steel profiles is weakened." Horizontal core drillings through the gravity wall from previous years have also shown that the wall thickness of the bank wall is no longer structurally sufficient. "We will therefore stabilize the masonry with a cement suspension and increase the statically effective wall cross-section," explains Siodmok.

The renovation of the wall section is similar to the renovation work that has been carried out since June on the natural stone retaining wall at the Abteigarten on both sides of the Inde. The maintenance work also involves repairing age-related damage. The renovation of the Inde retaining wall is being carried out in such a way that the characteristic appearance and the original natural stone appearance are preserved as far as possible. To repair the masonry, the base of the wall must first be renovated. To do this, the wall is underpinned and a scour protection is installed to protect the base of the wall from foundation damage. Later, the natural stone surfaces of the retaining walls will be renovated with a lime-based jointing material. The dilapidated parapets will also be replaced with new railings. This and other work is expected to be extended from June 2026.

All work to renovate and strengthen the wall contributes to flood protection and makes the embankment wall equally fit for the future.