EA50JG Offshore Structural Design – Jacket Platforms
10 Computational modelling and design
By way of finite element analysis using SAP2000 package the jacket platform. introduced in Lecture 4 can be simulated through the steps illustrated as follows:
Modelling and analysis phase
Step 1. Defining the grid lines
Step 2. Defining the section properties for chords and braces
Step 3. Defining the auto selection lists for the chords and braces
Step 4. Drawing the chords, plan braces, face braces and the representative tope side structure members
Step 5. Drawing the conductors using replication technique
Step 6. Drawing the conductor box at plan elevations by editing and adding members
Step 7. Replicating the front row of the conductors
Step 8. Incorporating the leg batters by modifying the coordinates at the plan elevations
Step 9. Pinned supports at the jacket base
Step 10. Defining area at the top deck level
Step 11. Defining dead, live and wave load patterns
Step 12. Assigning dead and live area loads at the top deck level
Step 13. Assigning wave, current and wind load characteristics following SAP2000 documents
Step 14. Defining LRFD design load combinations
Step 15. Running analysis, displaying deformed shapes and capture the support reactions
Design phase
Step 16. Choosing the design code
Step 17. Choosing the design load combinations
Step 18. Overwriting the chords K-factor
Step 19. Start design iteration until the analysis sections are the same as the design sections