Geogrid-reinforced bridge abutments
Solid bridge abutments made of reinforced concrete have been used in bridge construction for many decades. These are designed to be robust and low-settling. However, these advantages are offset by the technical and economic disadvantages of the in-situ concrete construction method, such as the comparatively long construction time and the possible differences in settlement between the almost rigid abutment and the adjoining, settlement-friendly dam structure. This can lead to a lack of ride comfort and damage to the expansion joint structures.
The international experience gained over more than three decades with the construction of plastic reinforced earth (KBE) allows this construction method to be used today as bridge abutments. This offers both economic and ecological advantages over conventional construction methods. By using KBE structures as earth pressure absorbers behind load-bearing components, solid concrete structures can be made significantly slimmer and more cost-effective. The “geogrid floor” composite body distributes the applied loads over a larger area, which leads to a high ductility of the structure. This minimizes differential settlements between the embankment fill and the bridge abutment.
In Japan, the high ductility has led to KBE constructions being established as the standard construction method for high-speed railroad lines due to their extraordinary robustness in the event of earthquakes. When suitable outer skin systems are used, the KBE construction retains its robustness even as a result of impact loads or in the event of fire. It can be easily repaired in the event of damage. The almost 100% recyclability of the construction and the approximately 85% reduction in greenhouse gas emissions compared to a technically equivalent steel-reinforced concrete wall speak for the ecological advantages of this construction method.