Geogrid-reinforced load distribution layers with Secugrid® HS high-tensile geogrids stabilize the new Wilhelmsburger Reichsstrasse, Hamburg
Location of work/project:
NAUE GmbH &Co.KG
At the future Wilhelmsburg-Centre junction in Hamburg/Germany, the transition between road embankment and bridge was achieved with a geogrid-reinforced load-distribution layer over vertical CMC columns (controlled modulus columns). Therefore high-tensile Secugrid® HS 1200/100 R6 was laid crosswise in two layers above the CMC columns.
The Hanseatic city decided to relocate the road and to combine it in a traffic artery with the railway line some distance away. Construction began in 2013. One of the challenges was the very weak subsoil. In particular, the transition between an engineering structure with deep foundations and the adjacent route made it necessary to compensate for the different settlement behaviors. At the future Wilhelmsburg-Centre junction, this transition between road embankment and bridge was achieved with a geogrid-reinforced load-distribution layer over vertical CMC columns. The design verification showed that the high-tensile Secugrid® HS 1200/100 R6, laid crosswise in two layers above the CMC columns, fulfilled the requirements for the structure.
For optimum execution, installation plans were drawn up for the individual areas which laid down the exact lengths of the individual geogrids. Secugrid® HS was produced in accordance with these lengths. The handling of the rolls on site was seen as being very positive. The relative stiffness of Secugrid® HS 1200/100 R6 compared to woven materials allowed a fast, taut and fold free installation on the formation, and the required wraparound length of the geogrids, which were laid at right angles to the axis of the structure at the edge of the load-distribution layer, was problem-free. In the difficult and challenging environment of the construction process, the installation of Secugrid® HS thus proved to be both safe, and easy to plan. In combination with the CMC columns, the reinforced load-distribution layer forms a safe base for the new Wilhelmsburger Reichsstrasse. After completion in 2019, the predicted traffic volume is 67,000 vehicles per day. Thanks to its high tensile strength, Secugrid® HS 1200/100 R6 will then permanently transfer the loads from the road embankment and the traffic to the load-bearing CMC columns, and will thus bridge over the soft subsoil.