Gentle Driving of Piles 2.0 (GDP2.0)

Publieke samenvatting / Public summary

Monopiles are the most common foundations for offshore wind turbines in the North Sea and the dominant method for installing them is by means of hydraulic impact piling. The main disadvantages of this method are (1) the generation of underwater noise, (2) the large loads transferred to the monopile, (3) relatively long pile driving time and (4) the fact that this method is not suitable for extracting piles again. The gradually increasing diameters of the monopiles are complicating all the aforementioned disadvantages.

The main goal of GDP2.0 is to design, build and test a large-scale GDP shaker in relevant conditions by means of an onshore/nearshore test campaign, focussing on engineering challenges related to the upscaling of the GDP technology. This is essential for continuation of the GDP development into a pre-commercial phase. The main innovations that will be developed are: 1. A novel shaker technology 2. A novel clamping system

Korte omschrijving
In the first development phase of the project, a conceptual design is made, and the novel shaker technology is developed on a small-scale. First, the design of an individual unit is partially tested. The results will be used for scaling up the shaker. Furthermore, the scaled units (at least two for the vertical vibrations and two for the torsional ones) are integrated in a small-scale shaker (1:100 lab scale) to test the novel technology. The next phase includes the integration of the array of shakers into the body of the shaker including a novel clamping system is made for the shaker. Figure 4 gives an overview of the activities conducted during the project. The third phase is the engineering, procurement & construction phase. In this phase a full-scale GDP shaker, designed for handling monopiles of 4 m in diameter, is developed. First, a novel clamping technique is developed and tested. This is accompanied by a detailed design of the scaled-up shaker, which is also tested. Finally, the newly developed clamping technique and the shaker are combined together with all support systems (electric, control) and integrated into a complete large-scale GDP shaker system.

The following results are expected to be delivered by the GDP2.0 project. 1. A novel design of a single units providing low-frequency vertical and high-frequency torsional vibrations. The design process of the array of units serves as a base of knowledge applicable in the pre-commercial GDP project. 2. A large-scale GDP shaker comprising an array of the aforementioned units, incorporating decoupled torsional and vertical vibrations control, including a shaker-to-monopile clamping system and including future proof up and down ending capabilities. 3. High quality GDP shaker test results in onshore/nearshore conditions, containing the GDP behavior in sand and measurements on the harmonic effects during installation and removal. 4. Detailed specifications for the commercial installation tool including the technology's area of application and its limitations. 5. A predictive model of the drivability of monopiles of the GDP technology.