EFFORTS

“Effective operations in ports”SP2 – Ports & Environment

23 september 2009

SIXTH FRAMEWORK PROGRAMME

Contract n° FP6-031486Workshop

Cathodic protection

HAVRE PORT

Le HAVRE PortLe HAVRE Port ’’ss AuthorityAuthority

Etat des poutres transversales

Conditions de travail difficiles

-- 2020 kilometerskilometers ofof breakwatersbreakwaters-- 3030 kilometerskilometers ofof quay wallquay wall-- dolphinsdolphins, dry docks,, dry docks, warfswarfs,...,...

INVENTORYINVENTORY

--betweenbetween 55 andand moremore thanthan 150150 years oldyears old

-- DIFFERENTS DESIGNSDIFFERENTS DESIGNS

-- CONCRETE (CONCRETE (caissoonscaissoons,, diaphragm wallsdiaphragm walls,,……))

-- STEEL (pilesSTEEL (piles and sheetand sheet piles)piles)

-- WOOD (PILES) AND MASONRYWOOD (PILES) AND MASONRY

-- ROCKS (forROCKS (for breakwatersbreakwaters))

QUAY WALL

::

12%

13%

20%55%

3 600 mlParoi moulée

3 800 mlCaissons en béton

6 000 mlPalplanches pieux

16 600 mlMaçonnerie/divers

QUAY WALL

Specificity of maritime structure

• Longer lifetime than human life

- Great changes in theenvironment during the life ofthe structure

• Use of huge area

- Maritime structures aregreat (quays, breakwaters),quite impossible to bedestroyed and the area isquite definitively occupied

• It is necessary to take intoaccount the futureevolution in the design ofthe structure

• It is necessary to maintainthe structure and to adaptthe construction to theneeds

Importance of maintenance andprotection of the structures

maintenance of maritime structure

SLOW

• Ageing of the materials

– Corrosion– Drive of the materials– Physic or chemical

dissolutions– Compressing,

displacements

PREDICTABLE ACTIONS

BRUTAL

• Damages

• Storms, meteorologicalevents

UNPREDICTABLE ACTIONS

Corrosion

Steel for reinforced concrete Coating of concrete

(5 or 7 cm)

Quality of the concrete

(density, rate Water/Cement)

Piles excedent thickness (1/10

Sheet piles per year)protection (paint, cathodicprotection)

Protection of steel structures

In Le Havre, the tide is more than 8 meters high

Various protections

- over the level of high tide : paint ACQPA IM2

(condition of sea water)

- under the level of high tide : cathodic protection

sacrificial anodes

outside source of current

- after correctives action for existing structures:seeling of holes by welding-on plates

Cathodic protection

Lowering the electro chemical potential of the work under- 790 mV: two ways

Creation of electro chimicalpotential between the steeland a more electronegatismetal (Al ou Zn)

Use of outside source ofpower.

Cost of energy

parasite current with negativeseffect an other structures

require electrical continuity

In Port of Le HAVRE: sacrificial anodes inAluminium

Sacrificial anodes

5 to 6 Kg / m2

potential lowered to - 850 mV

lengh of anod life of 15 years

survey witl checking of potentiel (1 year, 5 years, 10 years, 15years

Sacrificial anodes

2790 meters of quay wall under protection between 1996and 2009 (piles, sheet piles and dolphins)

400 t of anodes

Situation: corroded cage anddamaged concrete

Etat des poutres transversalesConditions de travail difficiles

Cathodic protection forDamaged concrete beams

- Destruction of damaged concrete- Change of corroded pieces of steel cage

- Reconstruction of the bottompart of the beams with specificconcrete

Reinforced cage with sacrificialanodes