Aarsleff Grundbau GmbH, the German part of the Aarsleff Ground Engineering Group, has successfully completed the installation of 4468No. precast piles for the bearing structure of a large photovoltaic project in Holland. The client, IB Vogt GmbH in Berlin, is a highly experienced and pronounced developer within the renewable energy segment with a firm focus on photovoltaic worldwide. As Aarsleff also has a long tradition delivering ground-engineering solutions for renewable energy projects (for instance, in Germany alone more than 5000 wind turbine foundations stand secure on Centrum precast piles), the client-supplier-fit is excellent: both parties are determined to contribute to the energy transition. In this project, the client is realising this innovative project in an unusual setting -the photovoltaic panels cover a very large 3m deep water retention basin, placed on lattice beams, and then mounted on the pile head in a grid of 6 x 12m. Due to poor ground conditions a deep foundation is a necessity. Being prefabricated, the Centrum precast piles enables this needed double function. The precast piles both serves as a mounting basis and a 3m high standing column, and as the deep foundation element. In comparison to in situ pile systems, this is a strong argument for the chosen pile system.
Before starting installation on site, some product development and additional soil investigations were carried out due to high demands for pile installation accuracy: +/- 5cm horizontally and +/- 3cm vertically. In the pile head a M42 threaded sleeve, provided through PFEIFER Bautechnik, is centrally positioned for a quick assembly of the beam connection. The transition piece between pile head and beam allows the necessary tolerance. To be certain about pile drivability and consequently reaching the planned pile toe depths and securing the vertical tolerance, additional CPTs were executed through FUGRO.
The team on site, consisting of the project manager Rainer Scharrel and his rig operators and banksmen, has performed very well – meeting all expectations to accuracy, quality, speed and health and safety standards. The two dispatched JUNTTAN rigs – PMx22 with a SHK5 hammer and PM25 with a HHK7 hammer – were ideally suited for the task.
Peter Wardinghus, Managing Director at Aarsleff Grundbau GmbH said:
“Our experience with this project has been very positive, especially the very partner like and professional cooperation with the client and his consultants. The suitability of the pile system has received a strong confirmation and more opportunities to plan, design and deliver smart ground engineering solutions within the renewable energy segment are in sight.”