A Closer Look at the Krammersluizen

Comprehensive inspections and assessments as the foundation for renovation

Through specialized inspections and in-depth material analyses, Nebest MOA Metaal, commissioned by the ZEEKR consortium, assessed components of the Krammersluizen complex, both above and below water. This provided a clear picture of the maintenance status and, based on targeted recommendations, offered concrete guidance for well-informed maintenance and renovation decisions.

Nebest’s involvement in the project began as early as 2018. “At that time, our diving specialists conducted extensive inspections below the waterline,” says Bart Vreugdenhil, project manager at Nebest MOA Metaal. “Concrete structures, steel components, and other objects were carefully examined to determine which parts required renovation. This information served as an important basis for the further preparation of the work.”

Structural safety

After the renovation contract was awarded to the ZEEKR consortium, additional issues arose that had not been identified during the initial inspections and preliminary investigation. “As a result, our concrete department was sent out into the field to examine, among other things, the lock chambers of the yacht locks and the push-boat locks,‘ says Bart. ’We determined the quality of the concrete through visual inspections, cover measurements, material testing, and laboratory analyses. In addition, we conducted remaining service life analyses and used test drilling to investigate what impact future modifications—such as the construction of the new spillway fish passage—would have on structural safety.”

Safe Use

Nebest MOA Metaal, in turn, focused on the steel components in the yacht locks. “One of our first assignments was to assess the maintenance gates used to drain sections of the lock chamber for inspection and maintenance,” Bart explains. “Although these gates have been in place at the complex for years, it wasn’t exactly clear when they had last been inspected. Based on structural inspections, measurements of material thicknesses, and an assessment of corrosion, we were able to determine that the gates were safe for use in the yacht lock.”

Blueprint

Nebest has now surveyed all the gates at the yacht locks, including the wall gates at the freshwater/saltwater separation point. “For a number of gates that show significant material loss, the manufacturer from the ZEEKR consortium is performing a recalculation based on our measurement results,” says Hein van den Hout, product group manager at Nebest MOA Metaal. “The gates are now safe to use, but any modifications could significantly extend their service life.” Nebest’s successful approach at the yacht locks led, at the request of the ZEEKR consortium, to a similar inspection approach for the barge locks. Hein: “We essentially created a blueprint of the inspection method used for the maintenance gates on the yacht locks and replicated it for the barge locks and the basin system.”

Proactive attitude

At the initiative of the ZEEKR consortium, Nebest MOA Metaal also conducted an additional assessment of the operation of various mechanical components in the lock chambers, because damage to the gears of the Panama wheel drive had been detected during a mechanical engineering inspection. “Using non-destructive testing techniques, we were able to rule out the presence of cracks,” says Hein. “However, we did identify a misalignment in the drive system. We then shared this information with Rijkswaterstaat, which indicated that it found such a proactive approach to be very valuable. After all, it wasn’t part of the scope of work. Thanks to this timely identification, we were able to propose targeted follow-up measures, resulting in Demako now including the realignment in the drive’s renovation.”

According to both gentlemen, what sets Nebest apart is its integrated approach. “Dive inspections, concrete testing, metal inspections, mechanical engineering analyses, coating recommendations, and document management are all carried out by a single organization. There’s no miscommunication along the line. Through a single point of contact, we ensure an efficient approach, a comprehensive overview, and concrete recommendations for action. Our collaboration with the client here at the Krammersluizen is so strong that whenever issues arise that require further investigation, the ZEEKR consortium knows where to find us.”