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.
Challenges
- 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.
Services
- 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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