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Hirschhorn Lockage - Concrete Repair

Concrete repair with WEBAC PU resins

The lockage in Hirschhorn on the Neckar river in the South of Germany was built as early as 1927 during the extension of the waterways. In 1958, a second,left lock chamber was added. In the year 1991, the steel components of the right lock chamber that are in contact with water were renovated. Severe damage to the right chamber necessitated fundamental renovation work in 2005 and 2006. These measures comprised concrete repairs at the right lock chamber including the approach peer and the middle quay wall leading to the left lock chamber. Moreover, the access to the left lock platform was done up and partlyrebuilt.The entire shipping traffic had to move through the left chamber in order to prevent water-way obstruction.
The lock chamber was full of cracks in the area of the construction joints. There were numerous almost horizontal cracks on both sides of the chamber in the area of the waterfluctuation zone. The top corners in the area of the casting joints were affected by short, diagonal cracks. Water was emerging from the majority of the cracks.
Within the framework of the renovation concept, the thickness of the lock chamber walls was reduced by 40 and 30 cm respectively (approx. 1,200 m³ of concrete). The actual geometry was then restored by means of a concrete facing provided with bracing fastened by means of shear anchors installed in the existing concrete.
Water-bearing cracks under hydrostatic pressure became visible in the residual cross-section of the concrete between the partial demolition and the installation of the concrete facing. After determination of the respective drill-hole grids, these cracks were first pre-injected with PU injection foam resin WEBAC® 150 and then post-injected with PU injection resin WEBAC® 1405 under pressure according to ZTV-ING.
The old construction joints were also filled with WEBAC® 150 and WEBAC® 1405. All these procedures were implemented while the left lock chamber was in full operation. Due to the constantly changing water pressure at approx. 5.3 m height of fall, the WEBAC products used are exposed to specific permanent stress. Thanks to WEBAC and a successful renovation concept smooth operation of the Hirschhorn lockage is and will be ensured.