The Galecopper Bridge is a 326m long steel cable stayed bridge that was built in 1970. The bridge carries a strategic motorway for the Netherlands. In addition, the bridge spans the Amsterdam Rijnkanaal which is one of the most intensively used shipping canals in the Netherlands.
Solving fatigue problems
Heavy freight traffic caused fatigue problems in the orthotropic deck. Strengthening involved the addition of a layer of high strength concrete to the top of the deck.
Together with our joint venture partners Royal HaskoningDHV and Greisch we have worked on this project as technical manager, site engineer, project and contract manager and managing contractor.
The structural design was challenging because of the correlation between the existing structure and the new designed elements. One of the design goals was to ensure that the profile of the strengthening beams matched that of the existing bridge, allowing future widening of the motorway. This formed a challenge for the camber calculations that had to allow for the changes in shape and stiffness of both the existing bridge and the strengthening girders throughout the construction steps. Careful monitoring of the shape of the girders during execution was necessary to ensure the correct camber of the girders. The measurements and monitoring gave opportunities for direct validation of the design calculations and required close collaboration with the steel fabricators.
The strengthening design allows for future widening of the motorway in combination with an increased clearance profile of the Amsterdam Rijnkanaal to allow passing of higher ships. After the strengthening the bridge will have an extended service life of 30 years.
The bridge is part of a large scale renovation project of eight steel bridges, also known as the Managing Contractor project, carried out in a joint venture with Royal HaskoningDHV.
Strengthening involved the addition of a layer of high strength concrete to the top of the deck. The main deck structure is strengthened by the addition of 2 large steel box girders (grade S460) recently installed alongside the full length of the bridge. The installation of the strengthening girders and the jacking of the bridge has been a spectacular process with large floating cranes, pontoons and mobile cranes all in action at the same time.
Each girder weighs 1500 tons and was installed in three pieces. First the side spans where installed, followed by the central section. The strengthening girders are connected to the existing bridge at two discrete locations. After the connection, the girders are individually jacked to transfer self-weight from the existing bridge. In this spectacular nightly operation the existing bridge deck is pushed upwards 250mm, relieving the existing cables and pylons of loads.
The high strength steel box girders strengthens the existing bridge by supporting the bridge’s self weight and the added stiffness further relieves the existing bridge from traffic loads.