A 143 Motorway Western Relief Road
Ing.-Büro WBI, Aachen
Walter-Heilit, Verkehrswegebau GmbH, ZNL, Magdeburg
Part of the German Government’s post-reunification transportation infrastructure renewal project “Verkehrsprojekte Deutsche Einheit”, VDE Road Project No. 13 comprises the A38 motorway connection Göttingen-Leipzig and includes the A143 western relief road at Halle. The scheme involves the construction of interchanges on the A7 at Göttingen and the A14 at Leipzig as well as the western relief road around Halle between the A38 and A14 motorways. As it approaches the residential suburb of Halle-Neustadt, the route crosses an area of former brown coal workings prone to the formation of sinkholes.
The most economic solution was chosen from the range of different options for ensuring the safety of the road. The geogrid used for this project was made-to-measure in accordance with the placing drawings. When a sinkhole forms, the geogrid bridges the resulting void and ensures the safety of the traffic above. The geogrid was placed in one layer longitudinally. The transfer of force was ensured by overlapping the geogrid longitudinally and transversely by the specified amounts. In order to mobilise the load capacity of the geogrid as quickly as possible in the event of a sinkhole forming, it was given a certain amount of pre stress during installation. To do this, there is a special placing beam, which applies a known pre stress related to the setting of its unrolling resistance. Fill was then placed over each length of geogrid, working forward progressively to fix the tensioned geogrid in position. This was followed by compaction of the gravel bedding layer. Thus 2.6 km of the A143 road in the Teutschenthal valley were protected. The all-purpose road L 164 crosses the A143 motorway here. A 280 metre length of this road was also protected by geogrid reinforcement against sinkhole formation in this area.