Civil Engineering Reference
In-Depth Information
1.0
0.9
0.8
0.7
(documented)
CP systems in NL
ultimo 2004
> 1 year old
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0
2
4
6
8
10
12
14
16
Age (years)
diamonds cumulative, triangles per year.
any more. Two of them have required moderate or major interventions. Nine
operate satisfactorily. Out of eight systems aged 8 or 9 years, the performance
of one is unknown and seven operate well. The youngest of these date from
1996, the year in which a CUR Technical Recommendation was published.
So, these 24 oldest systems were designed and installed without a regulating
document in place. Nevertheless, these old systems perform well: 16 out of
24 aged 8 to 16 years operate well without significant maintenance.
The inventory included 38 CP systems based on conductive coating
anodes, aged 2 to 14 years. In six cases the anode failed to some extent,
which was reported as:
•
local disbonding (in one case at 3 years old, which may not have been
working properly from the start; one after 9 years)
•
poor condition, one at 6 years and one at 7 years old
•
anode replacement, one at 7 and one at 10 years old.
In one case out of the total of 52 systems, anode-copper connections and
reference electrodes failed after about ten years. This was the first CP project
in The Netherlands, a bicycle path on a bridge installed in 1987. These items
were repaired for a modest amount of money in 1999 (Schuten et al., 2007).
Since then, it worked properly for at least several years (no recent information
available). In a total of nine cases (including the bridge mentioned above),
