Zollkanal, Hamburg

The Hannover branch has been deployed to one of Germany’s most beautiful locations: the southern Zollkanal in the Hamburg’s Speicherstadt district, which is also a UNESCO World Heritage Site. The construction project aimed to install a new 145m water-side sheet-pile wall with reinforced concrete waling, positioned in front of the historic quay wall. Aug. Prien Bauunternehmung Hamburg commissioned PORRs specialist civil engineering team to secure the sheet-pile wall. The back-anchoring involved 101 micropiles measuring up to 40m in length. The planning experts were responsible for execution planning, including structural engineering calculations for the grouted micropiles.

New structure following historic design

Around 2,600m of listed quay walls in the world’s largest historical warehouse complex are currently undergoing repairs, along with a further 1,650 m along the Zollkanal, which separates the Speicherstadt and Altstadt districts. Bacterial decomposition of the foundation piles and tidal effects had damaged the complex of structures built between 1880 and 1920.

One sub-project was to repair a stretch of quay wall measuring around 145m in front of the Speicher P building, along the southern Zollkanal between Kornhausbrücke and Jungfernbrücke. Significant cracks, deformation and damp areas had developed in the water side of the wall; bricks were also missing and the waling for the existing timber sheet piling had come loose in some areas

Innovative 3D modelling prevents collisions

Before the sheet piling was installed, the historic quay wall was anchored in place with micropiles. A district heating tunnel and the micropiles for the nearby Wandrahmsfleet building protruded into the ground where the back-anchoring was to be installed. A 3D model produced by the Stump-Franki planning team made it easier to coordinate work by different trades and avoided anchor collisions. As is the case almost everywhere in the Hanseatic city, tidal conditions presented certain challenges in this project. At high tide, the micropiles’ insertion points were underwater. At low tide, the working platform beached on the riverbed and could not be moved to the next drilling point. Despite this, all core drilling was completed precisely and on schedule. This was absolutely essential in this project because, once the sheet piling was in place, the micropiles were extended with a sleeve coupling on the water side and connected to the chord wall. Once the repairs were complete, the employer added a reinforced concrete quay head with a facing wythe to restore the quay wall’s original appearance.