Let's look at the FRP's closely
Fiber reinforced polymer (FRP) composites are materials made of fibers, such
as carbon or glass, embedded in a polymer matrix, such as epoxy. FRP
composites can be used to reinforce concrete structures by wrapping them
around columns, beams, and slabs. The wrapping process involves applying the
FRP material around the concrete element in multiple layers and then curing
the polymer to harden the composite.
The mechanism of how FRP
wrapping improves the seismic performance of concrete structures can be
explained as follows:
Increased strength: FRP composites
provide an additional layer of reinforcement to the concrete structure, which
increases its overall strength and stiffness.
Confinement:
The FRP wrapping acts as a confinement layer that helps to maintain the
integrity of the concrete structure and prevent it from cracking under seismic
loading.
Damping: FRP composites have a high damping
capacity, meaning that they can absorb a significant amount of energy during
an earthquake. This helps to reduce the level of damage to the concrete
structure and improve its overall seismic performance.
An example
of a building where FRP wrapping has been used to improve its seismic
performance is the San Francisco International Terminal. The terminal's
concrete columns were reinforced with FRP composites to provide additional
strength and increase their resistance to seismic loading. The project
involved wrapping over 800 columns with FRP composites, which helped to
improve the building's overall seismic performance and reduce the risk of
damage during an earthquake.