Buxtehude

A26

Frankipile NG® for two bridge structures

Bridge structures along the A26

The two engineering structures form part of the section of the A26 motorway near Buxtehude. Deep foundations were required for the abutments and supporting structures in order to transfer the loads from the structures into load-bearing soil layers. The client for the pile foundation works was Fritz Spieker GmbH & Co. KG.

Subsoil in marshland

The project site is characterised by the marsh soils typical of the region. Beneath a thin topsoil layer, peat layers up to four metres thick were encountered. These are followed by sands, which in turn are underlain by layers of clay and silt. Based on the geotechnical investigations, a pile foundation using cast-in-place concrete driven piles was specified. In the area of the peat layers, the work was carried out using casing pipes to stabilise the fresh concrete column.

Frankipile NG® with casing pipe

A total of 192 Frankipiles NG® were manufactured for the foundations of the two bridge structures. The piles reached lengths of up to 11.40 m and were designed for design loads of up to 3,400 kN. The pile toe was designed in accordance with the existing ground conditions of the load-bearing sand layers. The pile system was tailored to the geological conditions of the site.

Pile load tests to verify bearing capacity

Before the actual pile fabrication began, test piles were driven and subjected to static loading. A total of four static pile load tests were carried out. The load tests served to verify the bearing capacity of the proposed foundation system and formed the basis for the construction of the final pile foundation.

Foundation for the bridge structures

The installation of the 192 Frankipiles NG® laid the groundwork for the construction of structures BW 8091 and BW 8092a. The pile foundation transfers the loads from the bridge structures and forms part of the infrastructure works associated with the construction of the new A26 motorway.