The
Harkers Island Bridge replacement is North Carolina’s first bridge in which all
primary load-carrying components use internal fiber-reinforced polymer (FRP)
reinforcement. The project combines carbon FRP (CFRP) prestressing strands and
spirals with glass FRP (GFRP) bars in piles, girders, substructure, and deck.
This
companion research program documents bridge construction, characterizes the FRP
materials, and develops practical recommendations for project-level quality
assurance/quality control (QA/QC), detailing, and future code development. An
extensive material-testing program showed that all CFRP strands from 73
production lots exceeded the specified minimum strength and tensile modulus. Bent
bar tests on CFRP spirals confirmed substantial strength reduction at bends,
while GFRP bar tests verified compliance with ASTM D7957 but exposed gaps in
sampling and traceability. Statistical analyses indicate that 2 to 5 tension
tests per lot can provide acceptable confidence levels for project-level QA/QC.
Field observations informed recommendations on end-region detailing, lifting
systems, handling practices, and tagging. Overall, the project demonstrates
that all-FRP reinforced, prestressed concrete bridges are technically feasible
within conventional schedules and highlights where specifications, standards,
and QA/QC practices must evolve to support broader implementation.
