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OOO ХЮСКЕР
Ленинградское шоссе 69-1
125445 Москва
Россия

Geogrid-reinforced bridge abutments: report on a full scale test and executed projects

Abstract

Due to their economical, technical and ecological advantages, geosynthetic reinforced soil (GRS) walls and slopes have become a very popular and common solution. Realized projects show that there are hardly any limitations concerning height, inclination and shape. The gained experiences in the last years and the wide range of available geosynthetic reinforcements resulted in the use of the first geosynthetic reinforced earth structures as bridge abutments. Bridge abutments experience very concentrated and heavy Ioads and have to fulfil stringent limitations of deformation. To gain more information about the capability of reinforced earth structures as bridge abutments a real scale loading test was performed. The paper deals with the study of a geogrid-reinforced soil (GRS) solution for bridge abutments. A 4.5 m high geogrid reinforced vertical soil wall was directly loaded, near the top front edge, using a reinforced concrete block and hydraulic jacks, simulating the sill beam and Ioad from the bridge. Loading and unloading cycles were performed, where the Ioad was increased up to 3 times the normal Ioad for this kind of structure. Settlements and horizontal facing deformations were measured during the test. The paper will describe the full scale test in detail and present the important results and findings from the test. Furthermore a short summary of an executed project will be given.

Conclusion

A new direct connection (A74) between the Dutch A73 and the German Bundesautobahn 61 (BAB 61) in the area of Venlo, the Netherlands was constructed. Part of the construction consists of two 'ecoducts' that guarantee the ecological connection between the north and south side of the road. The left abutment of the viaduct was constructed as geogrid reinforced retaining wall with a max. height of around 10 m. After finishing the retaining wall, but before installing the sill beam and the bridge deck, a preload is applied to activate the initial deformation of the retaining wall. After preloading and finishing the construction of the viaducts, the retaining wall is covered by the Muralex® facing system (gabion like facing) for protection and aesthetical reasons. The horizontal and vertical deformation of the wall were monitored by 26 markers until two months after installation of the bridge, see Figure 7.

The figures show that all vertical deformations are nearly in the same order, both in the top as in the bottom of both embankments. This means that the settlements below the retaining walls dominate. The vertical and horizontal deformations are within in the expected range.