products such as vinyl decking, vinyl fencing, window and door frames with new products being
introduced at every building show. There is obviously a growing confidence in the uses for
9. Degradation over time
9.1 Please reference our UV testing as indicated in Section 5 of this paper. also reference
additional studies as listed in Section 10.
9.2 We have not observed any measurable change in Modulus of Elasticity in any project
to date. Nearly all changes observed in a retaining wall structure can be quickly associated with
changes in loading, under design of the structure and/or construction failures.
9.3 Regarding long term creep, we have found that if designs are based on Creep Limited
Stress below 4,000 psi, the material creep actually decreases over time. With over 20,000 hours
of creep data to date, we show that incremental deflection is almost not measurable. We are
seeing (2.7 x 10 -7) % based on ongoing testing.
9.4 We have not experienced any long term changes in impact resistance. The hundreds
of miles of vinyl sheetpile installed in every possible climate has not experienced any measurable
change in impact strength; even in the colder regions. Contractors still install vinyl in frozen
conditions (usually above 20 degrees) with every possible tool, including drop hammers.
Other pertinent information.
Project Name / Agency
Shelter Island Causeway
Cantelevered seawall with Rip Rap to
USACE / NY District
protect roadway from storm erosion,
Ctc. D Rackmales
over 1,000 lin ft.
US Navy / San Diego Pierwall
San Diego, CA
Sheets driven as facia, then grout
pumped behind in order to create a new
wall with old wall in place.
Wallisville Reservoir Cut-off
Sheets driven in dense clays with steel
USACE / Galveston District
mandrel, creating a cut-off wall, 350 ft
long, protecting bearing piles
Sheets driven in channel to allow natural
US Fish & Wildlife, US Forest
plantings to take hold, establish root
Service, DEQ, Bureau of Land
system, with sheets removed in 3 -4
Management, Bureau of