canal hurricane protection wall, installed by the Corps of Engineers (Wright, 2003), is a good
example of such accomplishment. Since its installation in 1998, it has survived three hurricanes
and five years of weathering without any visible structural damage, despite the accumulation of a
foot of flood-deposited sediments at the toe. A photograph of the wall shown in Figure 49 clearly
shows the verticality and alignment still well maintained. The only damage that occurred was the
accidental destruction of a foot of stickout in the high ground.
Conclusions
Field inspection showed no significant degradation even in ten-year-old sheet piles
Published research has shown that in five years of weathering very little degradation
happened in tensile strength and a slight improvement occurred in the flexural properties.
However, impact properties degraded with time.
The basic material, PVC, is well investigated, and exhaustive data are available from
organizations like Vinyl Institute, Vinyl by Design, etc
Corrosion degradation of steel pile was observed to be much faster than any degradation
of PVC sheet pile.
The four U.S. manufacturers of PVC sheet piles have different design approaches in
structuring the materials and profiling the shapes of the PVC sheet piles.
No ASTM standards or other standards were found to assess the performance of PVC
sheet piles.
Laboratory accelerated aging studies showed insignificant degradation in flexural
properties with aging.
UV exposure may cause discoloration after prolonged exposure.
UV exposure reduces notched impact strength, but the reduction rate can be quantified.
UV exposure tends to harden the surface. As a result, flexural properties tend to improve.
It provides better penetration resistance under low- and high-velocity projectile impacts
Recommendations
A solid design approach based on well-defined functional requirements needs to be
developed.
Functional requirements in addition to maintenance of long-term integrity must also
include the degrees of expected resistance to various hazards, such as accidental
overload, fire, impact, vandalism, etc.
Functional requirements should also take into consideration the special maintenance
requirements (such as frequent inspections, replacing damaged sheets, maintaining grass-
free footing, etc.) that may be necessary for using non-metallic sheet piling.
Life safety and other risks can be addressed by including them in the functional
requirements. The design must address the installation and maintenance requirements.
Manufacturers need to certify material specifications based on standardized testing
conducted by independent test labs.
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