Discussion on SI strategy for the Foundation design and installation assessment for pre-investigated sites

1. Home
2. Publications
3. Online Library
4. Discussion on SI strategy for the Foundation design and installation assessment for pre-investigated sites

 Recent advancements in geotechnical design for the offshore wind industry primarily result from the adoption 
of 3D Finite Element Method (FEM) modelling. Key innovations include the PISA approach for monotonic loading, as well 
as advanced cyclic methods such as the Capacity Degradation Model (CDM) and Stiffness Degradation Model (SDM) by 
Achmus et al. (2003, 2009), and NGI's Cyclic Contour Diagram models (Anderson, 2015). However, these models have not 
been comprehensively tested across diverse soil conditions, leading to their cautious application and resulting in conservative 
designs by engineers. A significant consideration in 3D FEM-based design is the use of robust constitutive models and 
accurate parameter assignments. This has necessitated a re-evaluation of site investigation strategies, given that the new 
design methods are more sensitive to laboratory testing, thereby increasing geotechnical investigation costs. It remains 
uncertain whether the still- high costs, particularly for in-situ testing (such as CPT), will lead to cost savings or de-risking 
during construction, including in foundation sizing and installation. This uncertainty, combined with higher expenses and 
extended timeframes required for obtaining detailed soil data, poses challenges for developers, particularly in the context of 
minimizing development costs. In this paper, the inherent uncertainty in geotechnical design methodology, irrespective of 
the availability of in-situ soil data, is compared with the uncertainty associated with predicted CPTs resulting from a high-
quality inversion exercise. This comparison aims to provide a basis for optimizing site investigation campaigns for pre-
investigated wind parks. 

5th International Symposium on Frontiers in Offshore Geotechnics (ISFOG2025)

1 - Site investigation strategies, geohazards and integrated studies