A key milestone is already scheduled for April: With the first handover of the excavation pit (Dock 4), the specialized civil engineering team will transfer responsibility for its work to the civil engineering team. The handover includes a partial acceptance inspection by the client and the local construction supervision team and marks the start of further tunnel construction work.

Underwater Work, Traffic, and High Voltage

The ongoing work places high technical demands on the team. In particular, the installation of grouted anchors to counteract groundwater pressure requires the utmost precision. In Dock 4, water columns of up to eight meters exert pressure on the excavation pit. This is a challenge that can only be overcome with extensive experience and meticulous execution.

At the same time, the final diaphragm wall work is underway in the so-called Island Dock 8 under extremely cramped inner-city conditions. The heavy equipment used here operates directly between moving street traffic and the light rail system with its 600-volt DC overhead lines. Safety and concentration are the top priorities here.

Multiple trades working in parallel

While the final diaphragm wall panels are being constructed in Dock 8, already completed excavation walls in Docks 4 and 10 are being back-anchored with grouted anchors. Additionally, dewatering measures and diving operations are underway.

At the same time, PORR Ingenieurbau is preparing for the start of tunnel construction work. Currently, head beams are being installed on the excavation walls, which will serve as foundations for construction cranes and concrete pumps in the future. Consortium partner Hagedorn is handling the excavation work in dry docks 4 and 6 as well as dredging operations from a pontoon in dock 2. Additionally, embankment widening is being carried out in the western construction zone.

Important milestone reached ahead of schedule

A significant milestone was already achieved at the beginning of the year. During a light rail service suspension from January 30 to February 3, the tracks were swung back into their original position via a temporary track bridge. The temporary bridge is supported by previously constructed excavation walls of Construction Dock 8 East.

This first milestone of the second schedule agreement with the client was the result of close collaboration among all consortium partners as well as the local construction supervision team. It was made possible by intensive day-and-night work in specialized civil engineering and continuous 24/7 operations in earthworks and track construction.

Digital planning supports complex construction processes

To manage the complex construction processes, the project team relies on digital planning and coordination tools. PORR Ingenieurbau has created a BIM-based 3D model that depicts, among other things, the temporary bridge, the tunnel structure, and the DB trough. Construction phases were simulated and processes optimized based on this model. In addition, construction progress is monitored via a detailed schedule that includes work items, quantities, and resources.

With the successful completion of the specialized civil engineering work in the first construction phase, PORR demonstrates its strength as a full-service provider: technical excellence, efficient processes, consistent quality standards, and genuine customer benefits—all from a single source.