Werne

Gersteinwerk power station

Retrospective foundation works with micropiles

36 micro piles for the new turbine foundation

A total of 36 composite micro piles were installed as part of the retrofitting of the foundations. The piles have a diameter of 160 mm, a load-bearing member diameter of 50 mm and reach drilling depths of up to 18.60 m. The micro piles supplement the existing foundations and bear the loads of the new machinery foundation. They thus form the basis for the refurbishment of the technical installations within the power plant. Even before the turbine and generator could be brought back into operation, the necessary foundation elements were constructed beneath the turbine table.

Work within the existing building

The existing foundations of the power plant are based on Franki piles. Due to the structural conditions within the building’s basement, micro piles were used for the retrofitting foundations. The work was carried out in what were at times very confined spaces, with clear headroom of just 2.05 m in places. The foundation work was coordinated with the existing building structures as well as the technical installations within the power plant. This is how the additional foundation elements were created within an existing power plant building.

Specialised equipment for low working heights

Two different drilling rigs were used to install the micro piles. In areas with limited headroom, the HBR202-E drilling rig was used. In sections with more space, the work was carried out using the KR704-2E drilling rig, which can handle longer pipe sections. Both rigs were deployed inside the building and enabled the piles to be installed within the existing constraints of the power station site.

3D modelling for foundation design

The retrofitting foundations placed high demands on the positional accuracy of the piles. At the same time, existing foundation elements, building structures as well as technical installations had to be taken into account. A three-dimensional model of the construction site was therefore created before work began. The model served as the basis for the arrangement of the piles as well as for coordinating the drilling positions within the existing structure. Based on this planning, the foundation works were carried out in sections.

The foundation for the power plant’s modernisation

Even before the modernised gas turbine plant commenced operations, the foundation elements for the new turbine base were installed deep within the power plant’s subsoil. The installation of 36 micro piles laid the groundwork for the subsequent refurbishment work. This marked the completion of a further section of the site’s technical infrastructure at the Gersteinwerk power plant.