πŸ“‹ Case Study

Offshore Wind Turbine Transition Piece

Fatigue-driven design of thick-walled RC transition piece exposed to cyclic wave loading and corrosion

πŸ—οΈ Project Overview

Monopile-supported 15 MW turbine in North Sea with 30-year design life

🎯 Challenge

Fatigue-driven design of thick-walled RC transition piece exposed to cyclic wave loading and corrosion

πŸ”§ Design Approach

High-performance concrete (HPC) with 12% slag, dual-layer cathodic protection, and fatigue-resistant detailing per EN 1992-1-1 Annex C

πŸ“ Design Diagram

Offshore Wind Turbine Transition PieceThick-walled RC HPC (12% slag)Δσₛ = 124 MPat_corr = 42 yrsFatigue-drivenCorrosion riskDual-layer cathodic protection β€’ EN 1992-1-1 Annex C

AI-generated project design illustration

πŸ“ Key Calculations

Fatigue Stress Range (Δσ_s)

Δσ_s = Οƒ_max βˆ’ Οƒ_min
Result: 124 MPa
Must remain below 140 MPa for 2Γ—10⁢ cycles

Chloride Ingress Time-to-Corrosion

t_corr = (x_c/2)^2 / D_eff
Result: 42 years
Validates 30-year service life with safety margin

πŸ“Š Results

Successfully passed scaled wave basin testing; certified for Class S4 exposure per EN 206

πŸ’‘ Lessons Learned

  • β€’Aggregate grading affects chloride diffusion coefficient more than cement type
  • β€’Embedded reference electrodes must be placed at critical tensile zonesβ€”not just cover depth

βœ… Key Takeaways

  • 1Aggregate grading affects chloride diffusion coefficient more than cement type
  • 2Embedded reference electrodes must be placed at critical tensile zonesβ€”not just cover depth