Page 30: of Offshore Engineer Magazine (Jun/Jul 2013)

29 31

EPIC

Corrosion problems solved with composite materials preserve steel structures, but over

Repairs of corroded supports are quick and effective when years, the constant exposure can lead composite materials are used; Victor Schmidt explains.

to exterior pitting and penetration. orrosion in the marine environ- waves. Corrosion weakens structures In addition, caissons for fre support, ment is a process constantly and can lead to buckling or complete which are open internally to move sea-

C acting on offshore structures, due to failure of supporting members and water, and drainage pipes are subject to immersion in salt water and constant attached cross-bracing. hidden damage. If corrosion weakens exposure to oxygen through wind and Routine maintenance will help pipes carrying crude or natural gas in the processing system, there is the potential for burst pipe and fre.

Replacing the weakened components is one option, albeit an expensive one. Another option is to clean and reinforce the affected supports with exterior protection: welding additional metal to cover and seal the corroded area, or applying a reinforcing clamp for added structural strength. Both increase dead weight on the structure and can change load dynamics. Clamps often must be custom built, have limited length, and may not be strong

Constant exposure to enough to hold wave loads.

saltwater or salt spray

Replacement or clamping strate- can lead to exterior gies work well on simple cylindrical pitting and penetration members, but become problematic of any steel support where complex joins bring two or more structure or piping.

support members together. They can

Source: Trac Oil & Gas.

also be problematic for process pip- ing with complex bends, and clamps

Repairing corroded piping are not adaptable for fanges or other using fber-reinforced protrusions.

polymers combines the

Another option is to use an easily strength of fbers with applied composite material that can the mold-ability and be shaped to the compromised com- corrosion resistance of plex structure. Composites combine the resins. two or more materials to form a new

Source: Trac Oil & Gas.

material with the strengths of both.

Fiber-reinforced polymers combine the strength of fbers (glass, carbon etc.) with the mold-ability and corrosion resistance of polymer resins. It is best to use glass fber where internal pres- sure retention is important and carbon fber where structural loads are critical.

Composite materials can be used in a wide variety of environments due to their service range. Workers can apply them in temperatures from

OE | June 2013 oedigital.com 32 032OE_0613_epic.indd 32 5/25/13 12:18 AM