Conference Session A11
Paper #2266
BRIDGE-IN-A-BACKPACK: SAVING THE NATION’S BRIDGES ONE
BACKPACK AT A TIME
Stephanie Fleck (saf68@pitt.edu), Greg Kuzy (ghk3@pitt.edu)
Abstract—Every day, millions of Americans rely on the
nation’s 600,000 bridges to commute to work and school
[1]. However, the nation’s bridges are falling into
disrepair. At the end of 2010, the U.S. Department of
Transportation deemed nearly 25% of the National Bridge
Inventory (NBI) to be functionally obsolete or structurally
deficient [2]. Through the use of fiber reinforced polymer
(FRP)
composite
materials,
Bridge-in-a-Backpack
technology presents an innovative solution to this crisis. The
Bridge-in-a-Backpack system combines FRP composite
tubes and decking with a concrete fill to create a
lightweight, yet powerful, corrosion-resistant system. First,
the paper will investigate, describe, and evaluate the use of
FRP composite materials in Bridge-in-a-Backpack, a
technology that will repair the aging road systems of
America. The paper will then delve into the detailed process
by which these unconventional composite bridges are
constructed. Next, the paper will explain how Bridge-in-aBackpack technology develops a “greener” attitude towards
the environment with the use of sustainable technology.
Finally, the paper will demonstrate the economic and social
benefits of this technology and will evaluate the ethics of the
bridge system. Abiding by the principles established by the
American Society of Civil Engineers (ASCE), the civil
engineers associated with Bridge-in-a-Backpack technology
apply their knowledge and skills to enhance human welfare
and the environment, with tangible results: a more
economical project, costing approximately 20% less than
steel and concrete bridges; one that inflicts less damage on
the environment; and one with fewer inconvenient detours
and delays [3], [4]. With advantages including strength,
longevity, and cost effectiveness, Bridge-in-a-Backpack
offers an attractive alternative to conventional steel bridges.
conditions contribute significantly to the United States’ nearfailing infrastructure grade of a D [2]. These unsafe bridge
conditions are a direct result from both age and insufficient
funding to repair them. Only about two fifths of the funding
required to maintain, renovate, and reconstruct these
deficient bridges are being invested; a total of about $930
billion is needed for these repairs, while only $380 billion is
being supplied [2]. Not only is the nation impeded by an
economic crisis, concerns of finite natural resources and
environmental impacts exacerbate the situation. In order to
accommodate for these environmental concerns, civil
engineers must take a more “sustainable” approach and
should thus consider energy and resource consumption,
social factors, and economic budgets in the life-cycle
analysis of the construction of bridges. Sustainable
development is a process of growth in which resources are
allocated in an efficient manner that meets the needs of the
current human population while preserving the environment
so that these needs can be met without compromising the
ability of future generations to meet their own needs [5].
With a limited budget and environmental concerns in mind,
civil engineers face the challenge of finding an economical
and sustainable solution to the nation’s decaying
infrastructure.
With both of these concerns in mind, researchers and
engineers at the University of Maine’s AEWC Advanced
Structures and Composites center have recently developed a
solution to this pressing issue: the Bridge-in-a-Backpack.
These bridges are constructed quicker than conventional
steel bridges with lighter, stronger, longer-lasting, and
corrosion-resistant materials known as fiber-reinforced
polymers (FRP). Such advantages offer a promising solution
to the decaying infrastructure.
Key Words—Bridge-in-a-Backpack, Bridge systems,
Composite materials, Deck replacement, Fiber-reinforced
polymer (FRP), Infrastructure, Sustainability
WHAT IS BRIDGE-IN-A-BACKPACK?
Bridge-in-a-Backpack (BIAB) technology was first
introduced in 2001 by the University of Maine’s AEWC
Advanced Structures and Composites Center. The University
partnered with Advanced Infrastructure Technologies, LLC,
a company devoted to using new materials and technologies
to improve bridge construction, and Maine Department of
Transportation to research and develop the new
technology. In lieu of conventional concrete and steel
bridge technologies, the main technology utilized in a BIAB
bridge is fiber-reinforced polymer (FRP) composites. These
FRP composite materials replace much of the corrosionprone steel used in the construction of a traditional bridge
spanning similar distances. Hollow FRP composite tube
arches that are filled with self-consolidating concrete
OUR DECAYING WORLD
Each day that aging bridges remain in a state of disrepair,
the infrastructure threatens the quality of life of every citizen
in the nation. Concrete supporting bridges’ entire structures
is crumbling away, and steel rebar reinforcements are
constantly deteriorating due to corrosion. One in four
bridges in the nation are structurally deficient and have
weight limits due to limited structural capacity or are
functionally obsolete, meaning that they cannot
accommodate current traffic volumes and weights [2].
According to the U.S. Department of Transportation, these
University of Pittsburgh
Swanson School of Engineering
April 14, 2012
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Stephanie Fleck
Greg Kuzy
function as the basic structure of a BIAB bridge. The ends
of the arches are secured in concrete abutments on either
side of the span. Then, the arches are covered with one of
two composite deckings: a lighter (thin) decking if a
concrete deck will be applied, or a heavier (thick) deck that
will be directly covered with gravel and earth [6]. If the
lighter decking is used, the structure will be covered with
gravel and earth after the concrete sets. Lastly, the road
surface can be completed on the level surface left from the
gravel and earth.
Since BIAB bridges are a relatively new development
that needed to be researched intensively before any
construction could go underway, they have just started being
constructed in 2008. Built in Pittsfield, Maine in late 2008,
the Neal Bridge was the first BIAB bridge ever to be
constructed for public use [6]. Constructed in a mere two
weeks, this bridge contains 23 of the FRP arches and has a
span of 32.5 feet over a stream [6]. The McGee Bridge, the
second bridge of its kind, was completed and opened to
traffic in August of 2009, just two weeks after its
construction began. Costing a low price of $89,350, this
bridge spans 28 feet across a small stream [6]. Both bridges
accentuate BIAB’s most innovative feature: FRP composite
arches.
and high-alloyed materials. Conventional steel rebar
embedded in bridge-deck concrete lies exposed to road salt
and water containing chloride ions that seep through cracks
in pavement. As seen in the picture below, this causes the
steel to corrode and expand, causing concrete to break off of
the bridge deck, which ultimately lowers the functionality of
the bridge [8].
FIGURE 1
CONCRETE CORROSION CYCLE [9]
However, FRP composite materials do not react with
chloride and are thus impervious to corrosion.
Furthermore, FRP materials are able to withstand higher
amounts of stress than steel. FRP materials have a tensile
strength of 1-1/2 to 2 times that of steel and weigh only 1/4
the weight of equivalent-sized steel rebars [7]. As described
previously, the thermoset resin of FRP materials causes it to
become permanently rigid and brittle, thus lowering its
ductility, or the malleability—the ability of a material to
deform. On the other hand, steel is a more ductile and
malleable metal. Due to this ductility, steel is prone to bend
and deform from high amounts of applied stress, whereas
brittle FRP materials can withstand higher amounts of
applied stress. However, because FRP materials are
extremely brittle, they are prone to immediate failure once it
reaches brittle shear failure [10]. This stress-strain
relationship is seen in the figure below.
FIBER-REINFORCED POLYMERS
An Overview of Fiber Reinforced Polymers
FRP composite materials are constructed through the process
of pultrusion with a polymer matrix, typically including
materials such as epoxy or polyester [5]. The pultrusion
process begins with a fiber-bundle of these materials that is
reinforced by “pulling” the bundle through a wet bath of
resin, including materials such as carbon, glass, or aramid.
FRP materials are considered a composite plastic, meaning
that two or more homogeneous materials with varying
material properties are combined to derive a product that
mechanically enhances the strength and elasticity of the
plastic base materials. Once the FRP becomes thoroughly
saturated with the resin mixture, it is then heated. These
thermoset resins have the property of becoming permanently
rigid once heated and cured, causing the FRP material to
have a high tensile strength while being lightweight [6]. This
process allows the FRP materials to be versatile and can be
constructed to any variety of sizes and shapes.
Advantages over Conventional Materials
FRP composite materials have numerous advantages over
conventional steel rebar. For example, because FRP
composite materials are composite plastics as opposed to
metals, they are thermal insulators, electrically nonconductive, electromagnetically neutral, and, most
importantly, noncorrosive [7]. Polymer plastics, a nonmetallic material, are resistant to chloride ions, which are the
main cause for pitting corrosion of metals, including steels
FIGURE 2
STRESS-STRAIN CURVE FOR FRP COMPOSITES AND STEEL [10]
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Not only are FRP composite materials becoming a more
popular material in construction due to their high strengthto-weight ratio and noncorrosive attributes, they are also
popular because of their ease of installation and costeffectiveness [11]. Because FRP materials are lightweight,
they do not require heavy machinery to move and install
them. As a result, transportation, labor, and equipment costs
are much less. According to Louis Triandafilou, a civil
engineer of the Federal Highway Administration, FRP
materials “have the potential to create cost-effective,
durable, and longer-lasting bridge structures… resulting in
lower life-cycle and maintenance costs” [6]. BIAB
exemplifies these promising attributes of FRP composite
materials.
heavy machinery or equipment is necessary. Installation of
the arches can be completed in a single working day [13].
Eliminating the need for temporary formwork and rebars,
these arches function as permanent forms for selfconsolidating concrete (SCC). Seen in the figure below, the
FRP reinforcement tube arches provide structural
reinforcement in the longitudal direction, in shear, and as
confinement.
Application in Bridge-in-a-Backpack
With the economy in a slump and environmental hazards
posing an imminent threat to the well-being of humankind,
researchers at the University of Maine set about developing
a low-cost, low-impact bridge: the BIAB. True to its name,
the BIAB’s core component of bridge construction, carbon
and glass FRP composite arches, can fit into a mere duffle
bag. The BIAB’s FRP composite arches, along with a
polymer composite decking, set the standards for the future
of bridge building.
BIAB’s FRP composite tube arches are manufactured
using a process called vacuum infusion molding process
(VIMP). In order to form a hollow composites shell in the
form of an arch, VIMP applies similar methods to the resin
transfer technique used to synthesize most FRP structures;
however, in VIMP, a polymeric film, commonly referred to
as the “vacuum bag,” replaces the stiff mold cover [12].
First, the film is sealed against the lower portion of the arch
mold at the periphery, and air is vacuumed from the mold
cavity. This causes compaction of the fiber-reinforcement
material of the arch due to atmospheric pressure exerted on
the outer side of the film. The final step of the process is to
impregnate a resin mixture into the mold cavity. Pressure
pulls the resin mixture through the fiber-reinforcement
material, which allows the arch to obtain a “high fiber, high
laminate” strength [12]. The arches must then cure, which
takes a matter of hours. Using the VIMP technique, the
resulting FRP arch has a fiber to resin ratio of about 60%,
which is higher than similar techniques [12]. In addition,
VIMP has little to no negative effect on the life-cycle of
BIAB; VIMP offers a short cycle time, low equipment costs,
low labor requirements, and allows complete elimination of
volatile organic compounds. Also, the forming and infusion
process can be performed in a shop or in the field. If
manufactured in a shop, the FRP arches can be flattened,
rolled up into a bag, and transported to the construction site
in the bed of a pickup truck.
Once on site and inflated to the proper geometry, the FRP
composite arches can be lowered into a shallow concrete
footing using a single boom and placed by hand labor—no
FIGURE 3
THREE COMPONENTS OF FRP REINFORCEMENT [9]
After the arches are in place, they are covered with a
corrosion-resistant FRP corrugated decking, which is
attached using screws that become “concrete anchors” once
the arches are filled with SCC [13].
To ensure structural integrity, BIAB’s FRP composite
arches have been subjected to various types of testing.
Before the bridge-system was implemented, researchers at
the University of Maine subjected FRP arches of varied
diameter and shell properties to static and fatigue tests to
predict non-linear load-deflection responses and capacities
of the FRP arches. As seen in the figure below, the behavior
of the arches were tested to within 3% of the finite element
modeling predictions [6].
FIGURE 4
BRIDGE-IN-A-BACKPACK’S FRP COMPOSITE ARCH EXPERIMENTAL AND
PREDICTED DEFLECTION SHAPE [9]
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In addition, the FRP arches were also subjected to twostage static load tests. The first test determined the initial
tensile rupture at the crown, at a load corresponding to the
pinnacle strength of the arch. It was found that the arch
maintained stability along with a significant portion of its
initial strength. The second experiment tested post-damage
behavior until tensile rupture at the shoulders of the arches,
signifying complete instability and failure of the arch [6].
Even though the strength of FRP materials is commendable,
their brittle nature is a disadvantage. FRP materials can
handle exceptional amounts of stress and pressure, but once
the pressure on the bridge reaches a certain point, the FRP
arches snap without any signal or warning. Unless each
structure is tested for this rupture point, this presents an issue
that threatens the public safety and welfare. When
considering the construction of a BIAB, this issue must be
taken into account.
Despite the drawbacks due to the brittle nature of FRP
materials, the FRP composite arches in BIAB provide
favorable solutions to the aging infrastructure. This
technology accelerates bridge construction and promises
long-term durability with low maintenance costs and
construction expenditures.
filling proceeds [6]. A continuous pour of concrete is
required on each arch to ensure structural integrity. Once all
of the arches are full, the concrete is allowed to set for 48
hours.
After the concrete has set, the decking process begins
with one of two options: a light composite decking that will
then be covered with concrete or a heavy (thicker) composite
decking. The light decking weighs approximately 150
pounds per panel and can placed without a crane, while the
heavy decking weighs approximately 500 pounds per panel
and requires a crane for panel placement [6]. In either case,
the positioning of the first panel is crucial to ensure that the
other panels are placed correctly. The panels are attached to
the arches using stainless steel fasteners. For the light
decking, once the decking is in place, steel rebar is placed
and a low slump (stiff) concrete is used to cover the decking
and reinforcement. With either decking option, gravel and
earth are used to fill and create a level surface above the
arches. The last step is the construction of the road itself. In
the image below, each component of the bridge can be seen.
CONSTRUCTION OF THE BRIDGE-IN-A-BACKPACK
SYSTEM
The construction of a BIAB bridge is fast and requires
hardly any heavy equipment to build. A small hydraulic
crane and a concrete pump truck are typically all that is
needed for the on-site installation of the bridge; however,
some excavation equipment may be required to prepare the
site for the abutments [13].
When the FRP composite arches arrive on site, they are
unloaded and placed. The arches are lowered onto the
abutment frames using a crane and, due to their light weight,
are placed in their final position by only a few men. A 12”
diameter arch spanning 50 feet weighs approximately 200
pounds, and a 15" diameter arch of the same length would
weigh approximately 250 pounds [7]. Once the arches are in
their final position, they are secured to the abutment frame
using wire fasteners, and are temporarily braced using
wood. When all of the arches are secured, the abutment
frames are filled with concrete, and the ends of the arches
become permanently secured in the concrete. After the
concrete sets, the wooden braces are removed from the
arches and the filling of the arches can begin. Filling the
arches requires a self-consolidating concrete (SCC). The
SCC mix includes a shrinkage compensating admixture, a
viscosity modifying admixture, a hydro-stabilizer (to
increase the workable life of the concrete), and a
superplastisizer (to reduce the water to cement ratio) [6]. To
minimize overflow and spillage, a fill box is used to
“funnel” the concrete from the pump truck into the apex of
the arch. Used for filling, vent holes located approximately
24 inches on either side of the hole allow air to escape as the
FIGURE 5
CROSS SECTION OF THE BRIDGE DECKING SYSTEM [14]
For BIAB bridges, the entire process takes approximately
two weeks to complete—which is much less than
conventional bridges. Positioning and securing the arches to
the abutment frames typically can be completed by a six
man crew in an eight hour shift [6]. Pouring the concrete for
the abutments takes several hours, but 48 hours are required
for it to set. The arches can also be filled within several
hours, but they require the same 48 hour setting time. After
the concrete is set, the decking process can usually be
finished in one day. In the case of the light composite
decking option, another day is required for rebar placement
and concrete pouring with an additional 48 hours for
setting. Next, the process of covering the structure with
gravel and earth fill can take one to two days. Lastly, the
road surface takes an additional day to complete.
Because of the low environmental impact, short
construction time, and less costs, the construction process
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can be considered one of many sustainable features of
BIAB.
stress and pressure. As a result, less resources, such as steel,
timber, and even oil and gasoline, are used, and less waste is
produced. Moreover, the FRP composite in the arches
protect bridges from corrosion and deterioration. Mentioned
previously in the paper, FRP composites are plastic, which
means they have a higher resistivity to corrosion and erosion
caused by the intrusion of water into the concrete structure.
This physical feature of FRP composite produces bridges
that are more resistant to the effects of aging, weathering,
and degradation, which allows bridges to last longer in
“severe exposure environments,” which results in lower life
cycle and maintenance costs [6].
The construction process of BIAB also has several
sustainable attributes. Like the production of the composite
arches themselves, the construction of BIAB lasts a
relatively short time—about two weeks. During the
construction phase, only small machinery and equipment is
needed to move, construct, and secure the components of the
bridge; FRP composite tubes only weigh a range of 200-250
pounds and can be placed by hand, rather than a crane.
Taking this one step further, the short construction time
decreases detours and delays that would cause problems
with commuting. Because society benefits from the short
construction time, this could be considered yet another
sustainable feature of BIAB.
Unfortunately, although BIAB offers many advantages,
challenges in developing and implementing the technology
exists. Experimental tests described in previous sections
have proven that FRP composite arches are stronger than
steel reinforcement; however, due to FRP’s brittle nature,
they are prone to complete and sudden failure under a
specific load capacity. At this rupture point, the pressure on
the structure becomes too great, the FRP frame can no
longer support the load, and the structure collapses due to its
inelasticity. Therefore, even though the FRP material
possesses high strength, the sudden failure threatens the
safety of society. However, engineers developing BIAB
have not overlooked this issue. According to the BIAB Fact
Sheet distributed by the University of Maine, sensors have
been installed on each bridge to continue monitoring of the
bridge, including load testing and instrumentation to
measure arch strains and deflections [13]. Testing will
document any changes in the response of the structure,
allowing engineers to closely monitor and control bridge
activity in case of bridge failure.
Another issue stems from the lack of ability to recycle and
reuse this technology. Unlike steel or timber, FRP composite
materials cannot easily be recycled. Once a FRP thermoset
composite is formed, the process is irreversible; they cannot
be melted and reformed to be reused to perform a similar
function in different structures. Because these materials
cannot be reproduced from existing materials, new products
have to be created for every project. This has a negative
impact on the environment, as more and more resources are
used and not recycled.
THE SUSTAINABILITY FACTOR
As mentioned previously in this paper, sustainable
development is the process of change in which resources are
used in an efficient manner that meets the needs of the
present without compromising the ability of future
generations to meet their own needs. Various methods can
be used to evaluate the sustainability of a project; one
evaluation involves Life Cycle Assessment (LCA) that
weighs the inputs and outputs for every phase of the
construction process, from conception and construction to
maintenance and recycling. The measure of the
sustainability of a project is centered on minimum resource
use, low environmental impact, low human and
environmental health risks, sustainable site design strategies,
and higher performance [5]. In order to achieve overall
sustainability, integration and an optimal balance of all of
these dimensions is needed.
Analysis of Potential Benefits and Challenges
An ideal sustainable project would have a closed life cycle
that has a minimal impact on the environment and society
while exhibiting a higher level of performance. Like any
other structure, BIAB has both advantages and
disadvantages.
Benefits of BIAB can be seen in its physical
characteristics, primarily in its FRP composite arches and
decking. First of all, the vacuum infusion process to
manufacture the FRP composite arches poses few negative
effects on the life cycle of BIAB. For example, the process
does not require a lot of machinery to produce the arches.
Instead, the process can be completed with a small crew of
workers in a mere couple of hours. This greatly reduces
equipment costs and labor costs, and it shortens the overall
construction time of BIAB. Furthermore, the vacuum
process allows for complete elimination of volatile
compounds, which reduces negative effects on the
environment, such as air pollution and acidification.
Aside from the manufacturing process of the FRP arches,
the arches themselves possess sustainable characteristics.
These benefits can be realized from the arches’ physical
attributes as well as their potential to enhance structural
systems’ service lives. FRP composite materials generally
have a high strength-to-weight ratio, which is true in the
FRP composite arches used in BIAB. In fact, FRP composite
materials consistently exceed the bridge design code
requirements for strength specified by AASHTO’s Load and
Resistance Factor Design guidelines [6]. As mentioned
previously, the lightness of FRP materials lowers
construction costs and speeds up the construction process,
which, in effect, results in reduced environmental impacts
[6]. In addition, the arches’ high strength and durability
require less materials to achieve similar performance under
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BIAB is a relatively new technology; therefore, the longterm effects of the life cycle of an actual bridge have yet to
be quantified. However, certain aspects of the life cycle have
immediate benefits to society, including shorter construction
times, lower initial cost, higher durability, and fewer
maintenance costs.
barrier from de-icing chemicals or salty environments. BIAB
has many benefits to offer society.
AN ETHICAL CHOICE
NSPE Code of Ethics for Engineers
According to the NSPE Code of Ethics for Engineers,
“engineering has a direct and vital impact on the quality of
life for all people” [15]. NSPE’s Code of Ethics provides
fundamental guidelines that every engineer should adhere to
in order to ensure a project’s success and to ensure public
safety. The first fundamental canon of the NSPE Code of
Ethics for Engineers states that engineers shall “hold
paramount the safety, health, and welfare of the public”
[15]. By utilizing BIAB technology as a tool to restore and
improve infrastructure, engineers strive to replace
structurally deficient bridges and ensure public safety while
using new money saving technologies. Bridges built with
FRP composite materials offer construction cost savings and
reduced maintenance costs as well as structural and
environmental strength. These BIAB bridges create a
smaller initial carbon footprint compared to other bridges
due to the requirement of less machinery during both the
production of the materials and the construction process
itself. On the other side of this ethical debate, FRP materials
have a somewhat unpredictable rupture point, which
presents an issue that threatens the public safety and welfare.
The rupture point of the FRP used in each bridge is different;
however, this issue has been minimized by placing
monitoring sensors on the bridges. With BIAB technology,
engineers serve public interest and “hold paramount the
safety and health and welfare of the public” [15].
Furthermore, no other bridge like BIAB has been
constructed before; therefore, the education and knowledge
of the components and techniques required to build this type
of bridge are critical. Given the specialization of the
technology, engineers involved with the BIAB system must
“perform services only in the area of their competence” and
thereby follow the second fundamental canon of the NSPE
Code of Ethics for Engineers [15]. More specifically, “only
when qualified by education or experience” should engineers
undertake assignments “in the specific technical field
involved,” such as BIAB bridge construction [15].
However, if engineers do not have the knowledge or
education necessary to positively contribute to the bridge
construction, they are in a direct violation of the
fundamental ethics of engineering.
SOCIETAL BENEFITS
The benefits of the BIAB system are not limited to the
sustainability and environmental aspects; they also
encompass numerous societal benefits. For example, the
BIAB system creates the opportunity for a much shorter
construction time than a conventional bridge, such as a
spread box beam bridge. Construction time for a BIAB
bridge averages at approximately two weeks from start to
finish. Even the first bridge of its kind, the Neal Bridge in
Pittsfield, Maine, was completed in less than two weeks. A
comparable spread box beam bridge would have taken two
to three months to complete. This comparatively drastic
difference in construction times correlates to shorter periods
of traffic due to construction or even road closures and
detours. Also, for citizens living near the site of the bridge
construction, the period of construction vehicle traffic to and
from the site decreases as well as noise coming from the site
itself.
Moreover, due to shorter construction times, BIAB allows
for a lower initial construction cost. In 2008, the Neal
Bridge cost just under $600,000; on the other hand, a precast
bridge built at the same time to bridge the same gap was
estimated to cost $770,000, producing a difference of
expenses around $170,000--a whole 20% more [3]. BIAB’s
cost saving of just over 20% poses a significant savings to
the government and in turn tax payers.
The projected life span of the BIAB system also seems to
be a benefit to the public. Although not proven, the life span
has been estimated at or greater than 100 years after testing
of the materials used in the bridge and simulations of 75
years of truck traffic on a bridge by repeatedly applying and
removing a load on a single arch. The average life span of a
typical bridge using steel and concrete, not FRP composites
ranges from 50 to 75 years, significantly shorter than that of
a BIAB type bridge. This difference means savings for
society and the environment. When the demand for bridges
decreases, tax payers surrender less money to the
government, and the environment is no longer negatively
affected by the consumption of resources and production of
toxins.
Another factor benefiting society is the fact that a BIAB
bridge requires less maintenance. Unlike a bridge with steel
beams, a BIAB never needs to be painted because it is not
made of metal. Since the concrete is fully encased in the
FRP composite tubes, maintenance due to cracked and
deteriorated concrete is eliminated. Without a path to the
concrete, water cannot cause cracking during freeze and
thaw periods. The FRP case also creates a corrosion resistant
ASCE Code of Ethics
The civil engineers associated with Bridge-in-a-Backpack
technology uphold the civil engineering profession by “using
their knowledge and skill for the enhancement of human
welfare and the environment,” ASCE’s first fundamental
principle of the code of ethics for civil engineers [2]. Two
fundamental canons in the ASCE Code of Ethics further
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qualify this civil engineering principle to civil engineers
involved with BIAB technology [2]. Like all engineers, civil
engineers “shall hold paramount the safety, health and
welfare of the public,” and civil engineers “shall perform
services only in areas of their competence” [2]. First, civil
engineers meeting transportation needs by replacing
structurally deficient bridges under 75 feet with BIAB
bridges help to ensure public safety and enhance human
welfare as well as recognize that their “engineering
judgments, decisions and practices incorporated in
structures” directly affect the public [2]. With advantages
including cost effectiveness, strength, and longevity, BIAB
offers an attractive alternative to conventional steel and
concrete bridges. Composite bridges using only concrete,
not concrete and steel, reduce effects of corrosion in the
environment. Additionally, at BIAB construction sites, the
technology utilizes customized bridge geometry that respects
water hydraulics of the specific environment [14]. Civil
engineers working with Bridge-in-a-Backpack technology
respect the ASCE Code of Ethics canon that details
improving the environment and enhancing public welfare
[2]. If they fail to follow the canon, they endanger the
current and the future health, safety, and welfare of the
public.
Not only do civil engineers associated with Bridge-in-aBackpack technology strive to comply with the principles of
sustainable development in the performance of their duties,
they also perform services only within their areas of
competence [2]. The new technology requires a level of
competency for civil engineers to “perform engineering
assignments only when qualified by education or experience
in the technical field of engineering involved,” the second
canon of the ASCE Code of Ethics [2]. Accordingly, the
first bridge to use the technology opened in Pittsfield,
Maine, fifty miles from the Advanced Structures and
Composites Center that developed the design [16]. Seven
years of lab testing at the Center qualified the assignment for
application [16]. Additionally, as researchers at the center
continually monitor the FRP composite material bridge, they
learn more about the technology and comply with the last
fundamental canon of the ASCE Code of Ethics [2],
[16]. This canon states that “engineers shall continue their
professional development throughout their careers . . .” and
details keeping current in specialty fields by participating in
continuing-education courses, reading technical literature,
and attending professional seminars [2]. Civil engineers that
develop or even follow new technologies like BIAB
understand the importance of continuing professional
development. They write or read technical literature
and “increase the competence and prestige of the
engineering profession” [2].
environment, and the infrastructure. With all these forces
fluctuating between a stable and unstable state, society needs
a lasting solution that will relieve pressure and bring society
closer to a state of equilibrium. Considering the rapidly
decaying state of the infrastructure, engineers must work to
derive such a solution that will benefit current and future
generations. One step towards this large scale solution is the
implementation of a new technology: Bridge-in-a-Backpack.
The BIAB system promises a viable means of replacing the
nations’ structurally deficient bridges up to a span of 75 feet.
This system features technologies such as FRP composite
arches and decking, which are stronger, longer-lasting, and
corrosion resistant--an overall more sustainable technology
than conventional steel bridges. In addition, the system
offers benefits ranging from faster construction times, lower
initial costs, longer lifespans, and less maintenance
expenses. Since this is a newer technology, certain
disadvantages appear to be a barrier to its feasibility as a
sustainable material, such as unexpected brittle rupture and
lack of recyclability; however, long-term effects of the
systems’ life cycle impact on society and the environment
have yet to be assessed. Immediate benefits, such as short
construction time and higher durability, present a positive
outlook for this technology. BIAB and its innovative
components set the standard for modern bridge technology,
bridging the gap to the future of infrastructure.
REFERENCES
[1] T. Barbaccia. (2010, Nov. 1). “The State of Your Bridges.” Better
Roads. [Online website]. Available: http://www.betterroads.com/betterbridges-2010-bridge-inventory/
[2] (2009). “Report Card for America’s Infrastructure.” ASCE American
Society
of
Civil
Engineers.
[Online].
Available:
http://www.infrastructurereportcard.org/
[3] J. Bloch. (2009, Feb. 21). “Giving shape to ‘bridge-in-a-backpack’
idea.”
Bangor
Daily
News.
[Online
Source]. Available:
http://www.lexisnexis.com/hottopics/lnacademic/?shr=t&csi=144564&sr=H
LEAD(Giving+shape+to+%27bridge-in-abackpack%27+idea)+and+date+is+February,%202009
[4] (2011). “Code of Ethics.” ASCE American Society of Civil Engineers.
[Online Web Site]. Available: http://www.asce.org/Leadership-andManagement/Ethics/Code-of-Ethics/
[5] L. Lee and R. Jain. (2009, Aug. 12). “The role of FRP composites in a
sustainable world.” Clean Technologies and Environmental Policy.
[Online]. Available: http://dx.doi.org/10.1007/s10098-009-0253-0
[6] L. Triandafilou. (2011, July). “Emerging Bridge Applications.” Public
Roads.
[Online].
Available:
http://go.galegroup.com/ps/i.do?id=GALE%7CA264014532&v=2.1&u=upi
tt_main&it=r&p=AONE&sw=w
[7] J. Busel. (2011, Sept.). “FRP Composites: Advancing Sustainable
Solutionf for Infrastructure.” Rebuilding America’s Infrastructure. [Online].
Available:
http://www.rebuildingamericasinfrastructure.com/magazinearticle-rai-9-2011-frp_composites-8502.html
[8] S. Mraz. (2006, Feb. 23). “Corrosion-resistant Rebar Builds Better
Bridges.”
Machine
Design.
[Online].
Available:
http://machinedesign.com/article/corrosion-resistant-rebar-builds-betterbridges-0223
[9] H. Dagher. “Bridge-in-a-Backpack Inflatable Composite-Concrete
Bridges.”
AEWC.
[Online].
Available:
http://www.nesmea.uconn.edu/pdf/09_frp_arches-dagher.pdf
[10] G. Asachi. (2008, Feb. 1). “Fiber Reinforced Polymer Composites As
Internal and External Reinforcements for Building Material.” Technical
BRIDGING THE GAP TO THE FUTURE
The world is constantly changing, being pushed and pulled
by the major forces driving society: the economy, the
7
Stephanie Fleck
Greg Kuzy
University.
[Online].
Available:
http://www.ce.tuiasi.ro/~bipcons/Archive/105.pdf
[11] W. Palmer. (2010, Feb. 19). “Strengthening Concrete Members With
Carbon Fiber Fabric and Epoxy Composites.” Concrete Construction.
[Online].
Available:
http://www.concreteconstruction.net/concretestrength/wrapping-it-up.aspx
[12] P. Zhang, H. Zhu, G. Wu, S. Meng, and Z. Wu. (2011). “Vacuum
Infusion Molding Process to Produce FRP Shell Used in an Innovative
FRP-Concrete Composite Structure.” Advanced Materials Research.
[Online]. Available: http://www.scientific.net/AMR.163-167.2147
[13] (2011, May 4). “Bridge-in-a-Backpack Fact Sheet.”University of
Maine Advanced Structures and Composites Center. [Online Web Site].
Available:
http://www2.umaine.edu/aewc/images/stories/bridge_in_a_backpack_flyer_
web.pdf
[14] H. Dagher (2011). “Bridge-in-a-Backpack.” AEWC. [Online Web Site].
Available: http://www2.umaine.edu/aewc/content/view/185/71/
[15 ] (2011). “NSPE Code of Ethics for Engineers.” NSPE. [Online Web
Site]. Available: http://www.nspe.org/Ethics/CodeofEthics/index.html
[16] H. Fountain. (2009, Oct. 13). “Building a Bridge Of (and to) the
Future.”
New
York
Times.
[Online
Source].
Available:
http://go.galegroup.com/ps/retrieve.do?sgHitCountType=None&sort=DASORT&inPS=true&prodId=ITOF&userGroupName=upitt_main&tabID=T0
04&searchId=R1&resultListType=RESULT_LIST&contentSegment=&sea
rchType=AdvancedSearchForm&currentPosition=1&contentSet=GALE|A2
09507439&&docId=GALE|A209507439&docType=GALE&role=
ADDITIONAL RESOURCES
J. Harrison. (2010, Nov. 20). “Bridge-in-a-backpack likely going to Russia;
Firm eyes technology for construction related to ‘14 Winter Olympics in
Sochi.”
Bangor
Daily
News.
[Online
Source].
Available:
http://www.lexisnexis.com/hottopics/lnacademic/?shr=t&csi=144564&sr=H
LEAD(Bridge-in-abackpack+likely+going+to+Russia+Firm+eyes+technology+for+constructi
on+related+to+%2714+Winter+Olympics+in+Sochi)+and+date+is+Novem
ber,%202010
ACKNOWLEDGMENTS
We would like to thank the University of Pittsburgh’s
School of Engineering for creating this assignment, for it has
given us a deeper insight into and appreciation for the field
which we would like to study. We would like to further
thank the University for providing an excellent online
Library System, which enabled us to easily research
different topics for this paper.
8
Stephanie Fleck
Greg Kuzy
ANNOTATED BIBLIOGRAPHY
V. Anumandla, G. Fu, R. Gibson, K. Warnemuende, H. Wu, and A. Yan. (2006, July). “Durability of FRP
Composite Bridge Deck Materials under Freeze-Thaw and Low Temperature Conditions.” ASCE Journal of Bridge
Engineering.
[Online].
Available:
https://sremote.pitt.edu/10.1061/,DanaInfo=dx.doi.org+(ASCE)10840702(2006)11:4(443)
This article, published by ASCE, details freeze-thaw and low temperature performance of fiber-reinforced polymer
(FRP) composites. The article describes how flexibility strength tests as well as modal vibration tests were
performed on FRP samples and presents the test results. Tables and graphs of the test results are included in the
research. Information from this article will help to better explain the properties of FRP composites and why they are
a viable material for building bridges.
G. Asachi. (2008, Feb. 1). “Fiber Reinforced Polymer Composites As Internal and External Reinforcements for
Building Material.” Technical University. [Online]. Available: http://www.ce.tuiasi.ro/~bipcons/Archive/105.pdf
This article, written for a construction and architecture journal, examines the advantages and disadvantages of using
FRP as an alternative and sustainable material in the construction of new and existing structures. The article
evaluates the strength of FRP paired with concrete elements and compares the strength of FRP reinforcements to
steel. This article will help evaluate the overall quality of FRP as a stronger, sustainable alternative to traditional
materials.
J. Bloch. (2009, Feb. 21). “Giving shape to 'bridge-in-a-backpack' idea.” Bangor Daily News. [Online]. Available:
http://www.lexisnexis.com/hottopics/lnacademic/?shr=t&csi=144564&sr=HLEAD(Giving+shape+to+%27bridgein-a-backpack%27+idea)+and+date+is+February,%202009
This newspaper article includes a short description of “Bridge-in-a-Backpack,” a recent bridge technology designed
by the University of Maine. The article presents a report of the materials used, the process by which the bridges are
constructed, and some benefits of employing this technology to replace deficient bridges. The information in this
article will provide the framework for the entire paper by providing an overview of the bridge technology on which
will be elaborated.
(2011) Bridge-in-a-Backpack. [Online Web Site]. Available: http://www2.umaine.edu/aewc/content/view/185/71/
The University of Maine’s website provides a fact sheet about the technology and the locations of the bridges that
have been constructed in Maine. The fact sheet provides a more in-depth description of the construction process and
advantages of Bridge-in-a-Backpack technology, and it introduces the environmental benefits of the bridges. This
source will help explain the construction process of the bridges, and it will help incorporate the environmental
advantages of using Bridge-in-a-Backpack technology.
(2011). “Code of Ethics.” ASCE American Society of Civil Engineers. [Online Web Site]. Available:
http://www.asce.org/Leadership-and-Management/Ethics/Code-of-Ethics/
The ASCE code of ethics presents civil engineers with a set of guidelines to work by. It is important for engineers to
recognize that that the lives, safety, health, and welfare of the general public depend on their engineering judgments,
decisions and practices. The policies of the code of ethics will help evaluate the ethical aspect of using FRP
materials for bridge construction.
(2012). “Composite Bridge
http://www.aitbridges.com/
System.”
Advanced
Infrastructure
Technologies.
[Online].
Available:
From the partners of the creators of Bridge-in-a-Backpack, this professional website offers resources that describe
the unique process of the newly developed Bridge-in-a-Backpack system. The website includes diagrams of the
stages of construction, a detailed illustration of the components, and project profiles of recently constructed bridges.
9
Stephanie Fleck
Greg Kuzy
These diagrams and project profiles will help illustrate the explanation of the bridge-building process while
providing concrete examples to support the analysis of the bridge-building process.
H. Dagher. (2009). “Bridge-in-a-Backpack: Inflatable Composite-Concrete Bridges”. AEWC Advanced Structures
and Composites Center. [Online]. Available: http://www.nesmea.uconn.edu/pdf/09_frp_arches-dagher.pdf
This PowerPoint, presented by the director of the AEWC, details the specific functions of the FRP reinforcement
tubes in the Bridge-in-a-Backpack system, including how FRP is a sustainable and economical way of building
bridges. To support this claim, the PowerPoint includes experimental data of load and pressure tests with graphical
data and qualitative explanations. This will determine the particular uses of FRP as a practical alternative
construction material in bridge building.
H. Fountain. (2009, Oct. 13). “Building a Bridge Of (and to) the Future.” New York Times. [Online Source].
Available:
http://go.galegroup.com/ps/retrieve.do?sgHitCountType=None&sort=DASORT&inPS=true&prodId=ITOF&userGroupName=upitt_main&tabID=T004&searchId=R1&resultListType=RES
ULT_LIST&contentSegment=&searchType=AdvancedSearchForm&currentPosition=1&contentSet=GALE|A2095
07439&&docId=GALE|A209507439&docType=GALE&role=
This article from The New York Times’ Material World details the construction of the Neal Bridge, the first of the
Bridge-in-a-Backpack bridges. The article describes how FRP are used in the construction of the bridges and the
advantages of the concrete being completely encased by the FRP. Information from this article will help better
explain what FRP is and why it is so important to the construction of Bridge-in-a-Backpack bridges.
L. Lee and R. Jain. (2009, Aug. 12). “The role of FRP composites in a sustainable world.” Clean Technologies and
Environmental
Policy.
[Online].
Available:
http://dx.doi.org/10.1007/s10098-009-0253-0
This scholarly article, written for the Clean Technology Environmental Policy, evaluates the feasibility of FRP
composites within a sustainable environment. The authors examine the life cycle of FRP composites, expressing
environmental, social, and economic concerns as well as its potential benefits. This evaluation will help predict the
impact of FRP composites on the environment as well as any long-term advantages or disadvantages of using this
alternative material.
W. Palmer. (2010, Feb. 19). “Strengthening Concrete Members With Carbon Fiber Fabric and Epoxy Composites.”
Concrete Construction. [Online]. Available: http://www.concreteconstruction.net/concrete-strength/wrapping-itup.aspx
This article, from a concrete construction website, provides a testament to the strength of FRP composite
materials. The article describes how FRP wraps are being used to strengthen existing bridges in California to make
them more resistant to earthquakes. These FRP wraps are lighter, cheaper, and stronger than traditional methods of
bridge strengthening. This article will help to emphasize the strength and value of using FRP and Bridge-in-aBackpack technology.
L. Triandafilou. (2011, July). “Emerging Bridge Applications.” Public Roads. [Online]. Available:
http://go.galegroup.com/ps/i.do?id=GALE%7CA264014532&v=2.1&u=upitt_main&it=r&p=AONE&sw=w
This article, from Public Roads (a U.S. Department of Transportation publication), details both FRP tube arches and
hybrid composite beam technology. The article explains how both the tube arch bridge and the hybrid composite
beam bridges are constructed. The hybrid composite introduces the concepts of compression arches and tension
reinforcement. This article will help illustrate the many applications of FRP materials in bridge construction.
10