Detailed engineering design was carried out in 2011-2012 for structural strengthening of an offshore tower to accommodate additional loading caused by higher metocean criteria.  

Project Scope

  • Analysis and design of strengthening for offshore flare tower, Goodwyn A-Platform.
  • The engineering works involved the assessment of load capacity increase by grouting of tower leg using Ultra High Performance grout.


  • About 30 scenarios were investigated to assess the load carrying capacity of the offshore tower.
  • The scenarios considered a composite case as well as various non-composite cases with different steel-grout interface bonds.
  • Also, different frictional coefficients and shrinkage effects were investigated.
  • Finally, the analysis considered different grouting heights and their corresponding load capacity improvements.
  • The engineering analysis was vetted in consultation with DNV and preparation for offshore implementation was then initiated.


  • The entire offshore tower was modelled with ABAQUS based on as-built structural drawings.
  • FEA was carried out using concrete damage material model for grout to understand the cracking or crashing of grout.
  • Steel was modelled as elastic-plastic material model.
  • Steel-grout interface was modelled as frictional bond.
  • The engineering approach also included a comparison of the analysis results derived from ABAQUS with those obtained from USFOS.

Client benefit

  • The analysis highlighted the load transfer mechanic between the steel and grout in the offshore tower
  • It was found that the load capacity of the tower may be increased up to 200% depending on the scenarios.

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