19 June 2001
TR 6: REPAIR OR RETROFIT TIMBER PILES WITH
AN UNDERWATER CURING EPOXY AND FIBER-REINFORCED WRAP
: Pile deterioration
by marine borers has occurred. Load requirements
preclude resolving the problem by using PVC or PE wraps or an increase in
strength (retrofitting) of intact piles is desired. In either case, deterioration cannot
be so extensive as to require replacing the pile.
Description of Repair: Remove rotted or damaged wood and all sharp or
protruding objects that could penetrate or deform the fiber wrap of the pile to be
repaired or retrofitted (see Figure 6-6). Fill in any holes and gaps with material
recommended by the system manufacturer. Saturate the wrap with the
underwater curing epoxy before applying. Apply vertical layers of the fiber wrap
with a 15-cm (6-inch) overlap. In most cases, it is advisable to wrap the fabric
around the pile from below the mudline to above the high water mark. Apply
horizontal layers of the fiber wrap with a 15-cm (6-inch) overlap. Additional
vertical and horizontal wraps are applied as required for sufficient strength and
as recommended by the manufacturer.
Application: This technology is designed to increase pile strength
characteristics, but may be limited by cost and confidence levels. In most cases,
PE or PVC wraps or pile replacement will be more cost effective for damaged
piles. In addition, because this is a relatively new technology option, long-term
performance has not yet been demonstrated. Environmental issues related to the
use of underwater curing epoxies must be considered.
Future Inspection Requirement: Basically the same as for a PVC-wrapped pile.
Any damage to the fiber wrap, however, could reduce the pile's load bearing