ABS - 308
GUIDANCE NOTES ON COMPOSITE REPAIRS OF STEEL STRUCTURES AND PIPING
|Publication Date:||1 September 2019|
This Chapter is applicable to the use of composite repairs on site-specific offshore units such as FPSOs and FSOs. It provides guidelines on adhesively bonded composite repairs of the steel structures. It covers assessment, design, qualification, installation and inspection of a bonded repair.
This Chapter does not cover aluminum structures, even though this guidance may also be applicable to aluminum structure repairs.
These Guidance Notes provide an alternative to regular hot work renewal, where the hot work is considered risky to the offshore unit´s operation. Instead of using hot welding, an existing degraded steel structure can be repaired to restore the integrity of the structure by utilizing patches of composite material, steel plates, or other structural materials that are bonded to the degraded steel structure.
1-1/Figure 1 illustrates the principle of a bonded patch repair. This repair technique can also be used for modification or upgrading of the existing structures by reinforcing structural elements to provide added strength.
Advantages of the bonded patch repair are that they are quick and simple with minimum preparation. Disadvantages are that the repaired section is thicker and heavier than the original, a very careful surface preparation is necessary for good adhesion and repair lifetime, and more frequent in-service monitoring and inspections may be required.