Affiliation(s)
Millan Engineering, San José, Costa Rica
ABSTRACT
In
Quepos, Pacific of Costa Rica, it was finished on 2010 the first phase of a
marina, including two mix breakwaters, with rubble mound (rocks and concrete
units), and 25 circular steel sheet piles cofferdam cells, filled with sand and
gravel. The maintenance plan, considers tracking sheet pile corrosion,
comparing 'actual' against expected rates, checking structural limits, and
programming countermeasures if accelerated corrosion is identified. Specific
control sections, along the breakwaters, both inside and outside the basin,
were established. In each section, thicknesses were measured every meter from
the top of the steel cell to seabed using an ultrasonic equipment, and an
underwater transducer. Both land crew, and divers for submerged portions, were used.
The measurements campaigns are for several years from 2011 to 2016. Sectors of
the breakwater with varied corrosion attack levels could be differentiated.
Also, corrosion rates and lifespans were estimated, both general for the
structures, and specific for each section and level. In turn, this allowed to
identify maintenance priorities, defining sites where measures of corrosion
protection should initiate, as well, to have confidence in the structural
capacity and safety of the breakwaters.
KEYWORDS
Monitoring of structures, maritime works, sheet piling, corrosion, ultrasonic thickness measurements.
Cite this paper
References
[1] Coburn, Seymour K. Corrosion Factors to be Considered in the Use of
Steel Piling in Marine Structures. Pile Buck, Inc, 2003.
[2] U.S. Army Corps of Engineers. EM 1110-2-2503 Design of sheet pile
cellular structures cofferdams and retaining structures. Washington, DC, 1989.
[3] Pile Buck, Inc, Cellular Cofferdams Jupiter, Florida.1990.
[4] Arcelor RPS (Rails, Piles & Special Sections), Arcelor Group.
Piling Handbook. 8th edition. 2005