Introduction
During the
past 20 years, FRP composite pedestrian bridges have provided
walkway solutions for both industrial and public applications.
Due to increased demand in backcountry locations for
recreational activities such as hiking, biking, horseback
riding, and off-road vehicles, FRP composite pedestrian bridges
have expanded trail and greenway uses into areas where
traditional bridge building has been more difficult. Over 100
FRP pedestrian bridges for public use have been installed
worldwide. Hundreds more have been installed in industrial
applications as walkways or catwalks. Most FRP composite
pedestrian bridges installed for public use have spans ranging
from 15 ft. (5m) to 100 ft. (30m). However, spans in excess of
200 ft. (65m) have been built.
FRP pedestrian
bridge framing system components are manufactured by the
pultrusion process
in a quality-controlled environment. High-strength FRP materials
such as glass or carbon fiber reinforcements provide the bridge
system with a
strength-to-weight ratio greater than steel, offering
significant design and erection advantages. The FRP pedestrian
bridge system uses typical structural
profiles including wide-flange beams, channels, angles, and
tubes. The FRP structural profiles can be prefabricated
offsite, and transported in lightweight component assemblies to
the site.
FRP composite materials are
inherently corrosion-resistant. This unique FRP materials
quality eliminates the ongoing maintenance concerns from
moisture, salt air, and termites that pose problems for typical
pedestrian bridges constructed in steel, wood and concrete. This
life-cycle performance of a pedestrian bridge is important on
most projects in remote sites, as access to the site for
inspection and repair is often not readily available after
initial construction.
Features and Benefits
-
High
Strength – Standard
components have strengths ranging between 30,000 - 60,000 psi.
-
Light
Weight – Standard components can be easily carried. The
bridge spans can be erected in most locations.
-
Modular Construction
–
Bridge
spans can be shipped fully assembled, partially assembled or
completely disassembled depending on site or project
requirements.
-
Easy
Installation –
Bridge spans are designed for quick and easy installation and
assembly.
-
Low
Maintenance – The FRP materials perform well in harsh
environments that quickly deteriorate more traditional
materials. Wet locations, termites, salt, and most chemical
environments have no effect on the material. FRP composites
are electrically non-conductive and easy to clean.
-
Attractive Appearance
– The bridge system can be specified in any color. The color
is pigmented in the resin. Therefore, painting is not
necessary.
Design
FRP structural profiles are
designed using traditional framing systems to produce the FRP
pedestrian bridge. The selection and design of the framing
system is dependent on the owners’ needs, loading, and site
conditions. The walkway wearing surface could be designed using
wood, concrete, or FRP composites in the form of panels or
open-hole grating, depending on the bridge owner’s requirements.
Consult the FRP bridge supplier for design guidance. Examples of
FRP composite pedestrian bridge structural configurations are,
but not limited to:
-
Pratt Truss
-
Howe Truss
-
Pony Truss
-
X-Braced Truss
-
Arch Truss
-
Cable stayed
-
Suspension
Connections
FRP
structural framing components are connected with mechanical
bolts. All bolted connections are designed as bearing type
connections. In some cases, use of adhesive bonding could be
used but only in conjunction with bolted connections. Separate
mounting clips may be required by the design. Clips are securely
attached to the foundation as required to provide adequate
vertical and horizontal support.
Assembly and Installation
Bridge installations used in
remote locations benefit from the high-strength and lightweight
characteristics of FRP composite materials. FRP pedestrian
bridge systems can be transported and installed without use of
the typical construction machinery, and without causing damage
to fragile ecosystems at the bridge site. The FRP structural
components are designed into an efficient system providing for
an extremely cost effective solution. FRP pedestrian bridges
are often located over existing high-volume traffic zones or in
recreational areas with limited access. In these circumstances,
bridge owners desire to have minimum impact on traffic patterns or
the site’s natural surroundings.
FRP pedestrian bridges can be
assembled and installed in a variety of ways. Spans can be
shipped to the site previously assembled, partially assembled or
in component parts. If shipped partially assembled or
unassembled, the spans can be assembled using standard hand
tools. The FRP materials lightweight characteristic allows for
quick installation on site with a small work crew. Assembly of
the FRP structural components on site might require temporary
supports and/or rigging depending on the job requirements. The
system can also be easily installed using a small crane,
helicopter, or even a forklift truck. For applications where FRP
bridges are attached to existing bridge structures, FRP
composite brackets can be used to support the bridge structure
to provide easy installation. The FRP pedestrian bridge system’s
easy assembly and installation is an important benefit compared
with other traditional systems constructed in steel, concrete or
wood.
Conclusion
FRP
composite pedestrian bridges offer a cost effective alternative
to traditional construction materials. The added benefits of low
maintenance / life cycle costs offset any higher initial project
cost. Given today’s concerns with replacement costs, FRP
pedestrian bridges become an attractive option when compared to
steel, concrete, and wood. Further, for existing vehicular and
railway bridges where there is a need to add pedestrian access,
FRP bridges offer the lightest and most easily installed
solution to the problem.
Go to pedestrian bridge supplier: E.T. Techtonics, Inc.
á
Top
|
Print
Entire Section
