Validation and Application of a New Software Tool Implementing the PISA Design Methodology

Ronald Brinkgreve,Diego Lisi,Miquel Lahoz,Stavros Panagoulias

doi:10.3390/jmse8060457

Abstract

The PISA (Pile Soil Analysis) research project has resulted in a new methodology for the design of offshore wind turbine monopile foundations. A new software tool called PLAXIS Monopile Designer (MoDeTo) has been developed that automates the PISA design methodology. It facilitates the calibration of the so-called soil reaction curves by automated three-dimensional finite element calculations and it allows for a quick design of monopiles using the calibrated soil reaction curves in a one-dimensional finite element model based on Timoshenko beam theory. The monopile design approach has been validated for sand- and clay-type soils which are common in North Sea soil deposits. The paper presents a validation exercise based on the PISA research project proposal of a rule-based parametric model—General Dunkirk Sand Model (GDSM)—for Dunkirk sand as well as an application of the tool for a project involving an offshore wind turbine on a monopile foundation in sandy layered soil in which the PISA design is compared to the conventional API design. The paper concludes with a discussion of the results and the differences between the various methods.

Highlights

In the last decade, offshore wind has proven to become a viable option in the transition from fossil to renewable energy sources
The PISA method allows for the rule-based design (RBD), in which pre-calibrated soil reactions for different soil types are used; the latter is mostly used in concept design studies
The second part of this paper describes a practical application involving a wind turbine on a monopile foundation in a sandy layered seabed

Summary

Introduction

Offshore wind has proven to become a viable option in the transition from fossil to renewable energy sources. In contrast to conventional design methods, it takes account of the positive effects of large diameter piles when subjected to bending moment and lateral loading at the top. Within the PISA method distinction is made between numerical-based design (NBD) and rule-based design (RBD). In the former, three-dimensional (3D) finite element calculations are performed to calibrate soil reactions within a given design space or calibration space (range of lengths, diameters, and other design parameters). The calibrated soil reactions, representing particular soil types or ground profiles, are used alongside a one-dimensional (1D) Timoshenko beam model with Winkler spring supports, to perform site-specific design optimizations. The PISA method allows for the RBD, in which pre-calibrated soil reactions for different soil types are used; the latter is mostly used in concept design studies

Methods

Results

Conclusion