During the last decade fiber reinforced polymer (FRP) materials have gained wide acceptance
for repair and retrofit of existing infrastructures or to design new infrastructures
due to their desirable properties (high strength to weight ratio, light weight and
consequent ease of field placement, corrosion resistance, durability, and low maintenance
cost among others). There is a need to strengthen the deficient and aging civil infrastructure
or new structures that are identified with certain design flaws against sudden loads
including impact, blast, natural disasters, or increased traffic loads over time.
The addition of FRP materials to upgrade the deficiencies or to strengthen the structural
components prior to collapse can save lives and damage to the infrastructure, and
reduces the need for their costly replacement. Furthermore, due to their desirable
properties, the retrofit with the FRP materials provides an excellent replacement
for traditional materials including steel jacket to strengthen the damaged reinforced
concrete structural members that are repairable. Phase I is ongoing and involves a
literature review to gather information about FRP strengthening of bridge related
projects and to evaluate the benefits associated with the FRP strengthening as opposed
to any other alternatives . The review also includes the bridge damage due to the
impact lateral load. The project is on time and up to date investigation indicates
the use of FRP materials is very promising as oppose to traditional strengthening
techniques used for bridge repairs. Numerous DOTs including NYSDOT, CALTRANS, WSDOT,
VDOT, and PennDOT are adopting FRP materials for repair and strengthening of bridges.
However, comprehensive data on full-size FRP-strengthened bridge columns are still
limited. Nonlinear finite element analysis is a great tool to augment the limited
available data on full-size columns in need of retrofit and allow detailed understanding
and improvement of design parameters. Initial interview with local engineers also
indicates the growing interest for the use of noncorrosive durable materials such
as FRP for repair and strengthening of bridge components. In phase II of the project
an innovative, reliable, fast, durable, and cost efficient FRP retrofit technique
will be employed to strengthen the bridges that are in serious need of repair due
to deterioration or accidental damage. To control the concrete cover spalling and
subsequent rusting of steel bars, the FRP sheet can be wrapped around the column.
Finite element analysis software program will be used to simulate the behavior of
concrete bridge column models prior and after fiber composite wrapping retrofit. The
as-built and FRP-retrofitted columns will be compared to access the confinement effectiveness
of the retrofit technique necessary to overcome the loss in the column strength due
to the deterioration and concrete spalling. Variables considered are the configuration
and the amount of external reinforcement. Depending on retrofit configuration, the
FRP-strengthened column will be able to not only gain its original strength that was
lost due to deterioration, but also carry the increased traffic load that was never
designed for. Such solution can postpone the costly replacement of the bridge or bridge
components while insuring the safety of the structure. Additionally, use of fiber
reinforced polymers offers an excellent alternative rehabilitation technique as non-metallic
sustainable reinforcement with considerable savings relative to conventional strengthening
methods due to the low maintenance and life cycle costs.
