Germany's Hamburg A7 Viaduct Completes Eight-Lane Expansion and Officially Opens to Traffic

en.Wedoany.com Reported - On September 28, the K20 Elbmarsch Viaduct (Hochstraße Elbmarsch) on the A7 motorway south of the Elbe Tunnel in Hamburg, Germany, completed its eight-lane expansion and officially opened to traffic. A completion ceremony was held on September 26, followed by the removal of the central median barrier, acceptance inspections, and traffic management conversion during the weekend closure period, with vehicular traffic resuming in the early morning of the 28th. The K20 main structure is approximately 3.8 kilometers long and has been expanded from the original six lanes (three in each direction) to eight lanes (four in each direction), making it the longest road bridge in Germany.

The project was commissioned by Die Autobahn GmbH des Bundes and managed by DEGES for planning and construction. The main expansion began in 2020, with a total investment of approximately 605 million euros, of which 142 million euros came from Germany's special infrastructure fund. The project was completed approximately 7 months ahead of schedule. During construction, the A7 — a major north-south traffic artery — had to remain in operation, and the builders in principle always maintained three lanes in each direction. New structures were added within the reserved space in the middle of the existing bridge, widening the bridge deck inward by approximately 4 meters on each side.

The original K20 bridge was put into service in 1975, with a bridge area of approximately 166,000 square meters, including 110 rows totaling 660 columns. Rather than completely demolishing the existing viaduct, the project added new bridge deck sections while retaining the original main structure, and simultaneously reinforced and renewed the existing superstructure, support system, and locally damaged large columns. Prior to construction, a 100-meter test section was specifically built to verify deep foundations, the connection between the existing bridge and new structures, and construction methods under heavy traffic conditions. Bored pile deep foundations were ultimately adopted, and the test section was directly incorporated into the formal works.

Implemented in parallel with the K20 was the reconstruction of the K30 ramp connecting to the Elbe Tunnel. The K30 has a total length of 418 meters. Its original bridge structure was demolished due to aging and damage and replaced with a new embankment-type structure composed of reinforced concrete retaining walls and fill structures. This section was put into service ahead of schedule in 2023. Together, the K20 and K30 form an approximately 4.2-kilometer A7 reconstruction section, which will connect to the future Hamburg-Hafen motorway interchange. This interchange will also connect to the A26 West line currently under construction.

This section of the A7 runs directly through the Port of Hamburg. According to DEGES data, the daily traffic volume on the section south of the Elbe Tunnel currently exceeds 116,000 vehicles, with heavy vehicles accounting for approximately one-fifth in historical traffic forecasts. With the eight-lane K20 in operation, the motorway between the Elbe Tunnel and the future Hamburg-Hafen interchange now provides continuous eight-lane traffic conditions.