Civil Engineering Reference
In-Depth Information
failure occurs when the fibers exhibit the extreme, often sudden and dramatic,
lateral or sideways deflection called fiber buckling.
The base fiber matrix is available in many forms, from random mixed fibers
to woven fiber blankets consisting of either glass fibers or carbon fibers. The
woven matrix provides the necessary bidirectional fiber strength, depending
on the strength requirements and application.
FRP
s response to transverse tensile stress is very much dependent on the
properties of the fiber and matrix, the interaction between the fiber and matrix
and the strength of the fiber-matrix interface. Generally, however, tensile
strength in the direction perpendicular to the fiber direction is very poor, so
the greatest tensile strength is in the direction of the fibers. The shear strength
of FRP is difficult to quantify. To avoid that, some products on the market have
the fiber in two directions, while other products have fiber in two diagonal
directions so that it can carry the load in the four directions. This type of
FRP composite will be used for repair on site, but prefabricated FRP used as
grating usually has fiber in one direction.
Besides FRP
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s high strength, its most relevant features include excellent
durability and corrosion resistance. Furthermore, the high strength-to-weight
ratio is of significant benefit; a member composed of FRP can support larger
live loads, since its dead weight does not contribute significantly to the loads
that it must bear. Other features include ease of installation, versatility, electro-
magnetic neutrality, excellent fatigue behavior, fire resistance and possible
maintenance-free use. So, FRP has increased reliability due to good corrosion
resistance and structural superiority because of weight savings, higher stiffness
and ability to better tailor the structure to the load.
The composite repair method takes less time offshore and involves light
material handling. The method often proves to be more cost-effective than
other repair solutions.
FRP has the following limitations, which can be easily overcome through
design and application and search for advanced products on the market:
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Brittle behavior
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Susceptibility to deformation under long-term loads
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UV degradation and photodegradation (from exposure to light)
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Temperature and moisture effects.
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s previous experience. How-
ever, the number and experience of contractors are increasing and are paral-
leled by continuous research and development aimed at enhancing the
properties of FRP.
Limitations are also related to the contractor
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7.12.13 Example: Using FRP
Davy and Bessemer are two shallow-water monopod platform structures located
in the southern North Sea that commenced production in 1995. These two
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