03-08-2012, 01:42 PM
Fiber-Reinforced Polymer Composites for Construction—State-of-the-Art Review
FRP Composites for Construction.pdf (Size: 202.73 KB / Downloads: 135)
Introduction
In the last 200 years, rapid advances in construction materials
technology have enabled civil engineers to achieve impressive
gains in the safety, economy, and functionality of structures built
to serve the common needs of society. Through such gains, the
health and standard of living of individuals are improved.
Structural Shapes
Introduction
Constant cross-sectioned FRP composite structural shapes, also
commonly referred to as structural profiles, produced for use in
the construction industry for building and bridge superstructure
applications are discussed in this section. Pultruded sections for
highway bridge decks are described elsewhere. Pultrusion technology
used for manufacturing FRP structural shapes is briefly
reviewed. This is followed by a brief discussion of the development
and evolution of structural shapes from nonstructural commodity
applications to current structural applications. Significant
building and bridge superstructure developments are described.
Recent research on pultruded FRP shapes is described and comments
on the future of pultruded structural shapes are provided.
Evolution of Fiber-Reinforced Polymer Structural Shapes
Large-sized pultruded FRP structural shapes @defined herein as
having a cross-sectional envelope greater than 1503150 mm (6
36 in.)# for building and bridge superstructure construction applications
were developed from earlier advances in pultrusion
technology, which prior to the 1970s was primarily focused on
developing small-sized commodity products for nonstructural
building and electrical applications. A key application driver that
led to significant developments and standardization of the technology
was the FRP stepladder. The seminal paper by Werner
~1979! describes the development of statistically reliable design
property values for pultruded parts used in the pultruded ladder
rail industry. B-basis allowable property values for design were
developed for pultruded channels used as ladder rails following
the procedures of the U.S. military handbook 17 ~Composite
2001!. In the 1970s and early 1980s, advances in pultrusion technology
led to the ability to produce larger pultruded parts capable
of serving as structural members in load-bearing applications.
Current Developments in Pultruded Structural Shapes
Since the 1990s, there has been a significant increase throughout
the world in the use ~albeit still on a demonstration project basis!
of pultruded structural shapes in primary load-bearing systems for
general construction. This excludes the cooling tower market,
which is a well-established niche market for pultruded structural
shapes. Significant bridge and building structures have been designed
and constructed using pultruded profiles.
Future for Pultruded Structural Shapes
The increased acceptance of pultruded structural shapes for mainstream
building and bridge superstructure applications will depend
on three key developments. The first is the development of
an internationally accepted material specification for pultruded
materials that will allow users to determine material properties of
interest to designers in a rational and nonproprietary manner with
well-known reliability. The second is the development of a design
code for pultruded structures that is consensus based and incorporated
into building and bridge codes such as the International
Building Code and the American Association of State Highway
and Transportation Officials ~AASHTO! bridge code. The recent
paper by Zureick and Steffen ~2000! provides an example of what
is needed to develop these two items. The third development required,
as is to be expected, will be to reduce the cost of pultruded
shapes, which are currently not competitive with shapes made
from traditional materials for mainstream structural applications.