Until 2019, around 55,000 vehicles, including 5,500 lorries, used Hamburg’s Wilhelmsburger Reichsstraße daily. The road was relocated with a railway line. Soft soils made the bridge-to-embankment transition critical, requiring reliable settlement control.
Until 2019, approximately 55,000 vehicles – including 5,500 lorries per day – crossed the Wilhelmsburger Reichsstraße, one of Hamburg’s most important north-south connections crossing river Elbe. The heavily congested route cut through the Wilhelmsburg district. The Federal Government of Germany and the City of Hamburg therefore decided to relocate the road in a major project and combine it with a railway line to create a new traffic artery. One of the biggest challenges here was the difficult ground with soft organic layers, peaty subgrade, subsoils and transitions to structures with different foundations.
The transition area between a deeply founded bridge and the adjoining embankment section was particularly sensitive. Here, large differences in settlement had to be reliably avoided in order to create a solution that would be fit for purpose in the long term.
An innovative foundation system was used to transfer the traffic loads safely and permanently into bearing capacity soil layers. It combines:
The foundation pad rests on a grid-shaped ground improvement by rigid inclusions, consisting of hydraulically bonded, unreinforced, slender pile-like load-bearing elements (Ø 32cm, centre distance 1.5m), which is precisely matched to the orthogonal alignment of the geogrids. It safely transfers the dead loads of the embankment (up to 140 kN/m²) and traffic loads (52 kN/m²) into the bearing capacity of the subgrade, subsoil – even with a construction height of up to 7.6m above the foundation level.
The two geogrid layers were laid crosswise (lengthwise and crosswise to the route axis). Special attention was paid to deformation compatibility and long-term stability. The long-term elongation was designed to be well below 0.5% – a prerequisite for long-term serviceability.
The system was installed efficiently despite the cramped conditions on site: Almost 32,000m² of the customised geogrid was delivered on time and laid quickly without creases. The high inherent rigidity of the Naue Secugrid® HS rolls made installation considerably easier – a clear advantage in complex construction conditions.
Ground improvement using rigid inclusions, in this case Controlled Modulus Columns CMC©, also proved to be economically and ecologically advantageous: there is no excavation that needs to be disposed of and the ground is improved through displacement and compaction.
After commissioning in 2019, around 67,000 vehicles have used the new route every day. The particularly critical transition area between the bridge and embankment will remain serviceable in the long term thanks to the optimised and consistently planned system.
A project that shows how geosynthetics and innovative foundation technologies can work together to create high-performance infrastructures.
Secugrid® HS distributed loads efficiently and reduced differential settlement at the critical transition between bridge and embankment.
The reinforced load transfer platform safely carried high embankment and traffic loads while maintaining long-term serviceability.
The high inherent rigidity of Secugrid® HS enabled quick, crease-free installation under challenging site conditions
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