From Espelkamp to Utrecht. All motorways in the Netherlands, regardless of whether they are numbered with single or doubledigits, are called Rijksweg. Those are the roads that the Dutch transportation ministry constructs and maintains. The A2 is one of these Rijksweg roads; it runs from Amsterdam via Utrecht and Eindhoven down to the Belgian border at Maastricht. Between Amsterdam and Utrecht, the A2 is the same as the European Road 35, which runs via Frankfurt am Main (Germany) to Rome (Italy). In the course of the expansion of the A2 motorway the connection near Utrecht was rebuilt. Both directions of this major European road now have five lanes each. Reinforced noise protection barriers were part of the project. The Dutch authority Rijkswaterstaat and Trajectum Novum managed the project in an alliance of equals. “Rijkswaterstaat” was founded in 1798 as the Office of Water Architecture and today is a department of the Dutch Ministry of Transport, Public Works and Water Management. This ministry, in general, is responsible for the construction and maintenance of streets and waterways. The alliance was jointly responsible for the budget of the total construction measures and, thus, both participants are committed to its success. “The Netherlands has never before seen anything like this,” says Lars Vollmert, managing director of BBG Bauberatung Geokunststoffe GmbH & Co. KG, headquartered in Espelkamp (Germany). Short coordination and decisionmaking processes allow for planning during construction and swift implementation. In the qualification phase, Trajectum Novum, a project-related conglomerate of several construction companies and planning offices, made the decision to have NAUE supply the geogrids that are needed for the reinforced noise protection barriers and to have BBG Bauberatung Geokunststoffe supply the technical support for the planning department of the alliance. “We were able to gain ground due to the comprehensive delivery program, sophisticated reference projects and the cost effectiveness of the products,” says civil engineer Walter Ewert, NAUE’s sales director for Germany and boardered countries “The total package, consisting of the preliminary design, delivered product and services as well as the promised technical support during the planning and execution phase made all the difference.”.
Reinforcing the Future
In cooperation with the technical department of Trajectum Novum, the BBG Bauberatung Geokunststoffe worked out the technical drafts and execution details. For guaranteeing the stability of street on-ramps and in the construction of noise protection barriers, geosynthetics play a key role. Engineers planned a unique, 4-km-long noise protection barrier and numerous steep embankments, all of which are being constructed with geosynthetic reinforced mechanically stabilized earth (MSE) structures. These structures were built in part on solid ground but ground that is prone to subsidence. Partial areas thereof would have to be preconsolidated ahead of construction by means of hydraulicfill sand and vertical drains. Lars Vollmert from BBG explains: “The MSE will be constructed using either the wrap-around method and planted with grass or vegetation, or it will receive an outer skin comprised of steel grid elements that is backfilled with stones. Upon request of the designer, the steel grid elements were not galvanized, and the diameters of the steel elements had to be adjusted to meet the required service life”. In order to achieve the required stability, geosynthetics from NAUE were being used, such as Secugrid® geogrids, to create a long-term, secure and economical MSE structure. This project phase included the entire infrastructure measures, from draft to construction of the part of the A2 between Leidsche Rijn Tunnel and the Autobahn cross at Oudenrijn.