A45: Second use for metal polymer at the Lennetal bridge
Bridge bearings one hundred percent form and force-locking connected
For the second time, a special metal polymer played a major role in the construction of the Lennetal bridge in the course of the A45: the bridge bearings of the bridge section towards Dortmund were now permanently connected to their metal trough – the support frame for the concrete runway. Of particular importance here is the one-hundred-percent form and force-locking gap compensation between the bearings and the bridge trough.
After around 50 years of service and continuous load, the new Lennetal bridge was built in September 2013 as part of the A45. The new bridge will consist of two structures resting on two pillars each with a span of almost 1,000 meters. The superstructure is formed by a closed steel box with laterally arranged struts and a solid concrete slab of reinforced concrete.
The new bridge construction is being built using the so-called cycle shift method. Here, prefabricated bridge components are welded together on site in the so-called clock cellar and advanced piece by piece until they meet the already standing centerpiece of the Lennetal bridge. They then have to be connected to it with millimeter precision, guaranteeing the 100 percent power connection between the bridge bearings and the supporting metal trough.
Due to the process, deviations in the final positional tolerance of the contact surfaces occur during welding in the clock cellar as well as due to the size and weight of the individual bridge components. These can neither be planned nor foreseen in advance and only appear after the final position. Common methods for gap compensation, such as the insertion of shim plates are then possible, but associated with high time and cost in surveying, manufacturing and installation.
The solution was provided by the metal polymer MM1018 of the German Diamant Metallplastic GmbH, which has proven itself in the bridge construction industry. This product is a two-component reaction resin system that combines steel-steel and steel-concrete joints securely and with 100% strength. After 24 hours it is fully cured and fully loadable. In 2016, MM1018 had already frictionally connected the bridge bearings of the first part of the Lennetal bridge with the steel trough.
In contrast to the old Lennetal bridge, the new one consists of two structures whose lanes in the course of the A45 run parallel to the one in the direction of Frankfurt and the other in the direction of Dortmund. Therefore, in the first construction phase west of the existing bridge provisional pillars were built, which already carry a lane of the new bridge. Thus, in addition to the old structure, the new superstructure west (direction Frankfurt) was built temporarily. This superstructure will later be completely moved to the new abutments in the planned end position.
Diamant Metallplastic GmbH, based in Mönchengladbach in the Rhineland, develops, formulates and produces metal polymers and coatings for the metalworking industry, casting, steel and bridge construction and shipbuilding. Founded in 1886 and still managed as a family business, Diamant Metallplastic GmbH has a global sales network with over 40 foreign representations in major industrial centers around the world.