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Pile foundation for motorway cover (First BA), Hamburg

Facts and Figures
Company PORR Spezialtiefbau GmbH
Principal DEGES
Location Hamburg - Germany
Type Foundations
Runtime 02.2017 - 07.2017

Pile production with flowing traffic on the A7

Three noise protection tunnels are planned along the A7 motorway in Hamburg. The aim is to "merge" the Schnelsen, Stellingen, Othmarschen and Bahrenfeld neighbourhoods and protect residents from road noise. The motorway will be widened to eight lanes to improve traffic flow. The bidding consortium PORR Spezialtiefbau/Hochtief Infrastructure GmbH won the public tender organised by DEGES for the 1,970 m long Stellingen section of the motorway.


2,620 piles for motorway cover in Hamburg-Stellingen

Contrary to the original planning with jacket-grouted large bored piles (d = 120 cm), the PORR special civil engineering special proposal will be realised with Partial displacement bored piles. In the area of the 900 m long tunnel section, sands and boulder clay are present in varying layer thicknesses and heights. The piles are set in the sands. In order to optimise the embedment length in the sands, several static test loads were carried out in advance. This resulted in a minimum embedment depth of one metre in the load-bearing sands. The so-called cover in Stellingen is deeply founded with a total of 2,583 piles. In order to be able to absorb horizontal loads during construction, the piles are inclined.

Special challenge due to construction site location

Construction site logistics and occupational safety posed a particular challenge during construction. In addition to the construction site traffic, the activities of other trades and subcontractors also had to be taken into account on the closed carriageway. However, motorway traffic with a distance of just two metres in front of the equipment was also not a daily occurrence. In July 2017, work on the northbound carriageway was completed on time and without any accidents. 

Some large bored piles were installed at a limited working height due to a culvert and an existing bridge.

Services 1st construction phase:

1,300 Partial displacement bored piles d = 78 cm, Nd ≤ 2,811 kN, L ≤ 14.0 m    
7 static test loads       
37 large bored piles d = 120 cm, L ≤ 8.0 m