Civil Engineering
2159
EARTHQUAKE PROOFING BRIDGES
Brian Sugarmann (bws15@pitt.edu), Benjamin Tyke (bjt31@pitt.edu)
Abstract—Engineers have struggled to design bridges that
can withstand the forces created by earthquakes due to the
inherent vulnerability that bridges hold to seismic energy.
Recently, there has been a push in bridge design to apply the
structural fuse concept, which saves the integrity of a bridge
by implementing devices that absorb the forces from an
earthquake. There are many types of structural fuses, but the
main focus of the paper will be on the Buckling Restrained
Brace (BRB), the most effective structural fuse.
This paper begins by looking at different sections of a
bridge that fail during an earthquake. This leads into an
explanation of the structural fuse concept, which will
provide a transition into the main topic of the paper, the
BRBs. The importance of BRBs will be described to help the
reader to gain an appreciation for the BRB technology. This
will continue into a description of the BRBs from a
structural and material standpoint, showing different factors
that make the BRBs more effective. The advantages and
disadvantages will be discussed, with an emphasis placed on
the costs of the BRBs. Next, the BRBs will be looked at from
a construction standpoint of new bridges and in the
retrofitting process. The BRBs will also be discussed from
an ethical prospective by looking at two sources of ethical
codes, The National Society of Professional Engineers and
The American Society of Civil Engineers, and then applying
these codes to the BRBs. The conclusion will emphasize the
possibilities of future research, such as bridges that are
earthquake proof.
The Superstructure is the deck of the bridge, which is the
area that is used to transport loads, which are most
commonly vehicles [1]. Superstructures are the easiest of
the three sections to fix after an earthquake and usually take
the shortest amount of time to replace, but they cannot be
fixed until the Bearing and Substructures are replaced. The
Superstructure does not collapse directly from seismic
energy; rather, it is a form of secondary damage caused by
the failure of the substructure to absorb the energy [2].
The Substructure is most important part of a bridge’s
infrastructure and consists of the foundation and the piers or
columns of a bridge [1]. The Substructure holds the bridge
into the ground with the foundation and then rises from the
ground with the columns or piers. The Substructure must be
capable of holding the vertical load of the bridge, while
having the elasticity to not fail due to lateral loads. A lateral
load is any force acting horizontally on the bridge, such as
wind or more damaging forces like seismic energy [1]. The
vertical loads are any forces acting vertically on the bridge,
such as the weight of a car.
The Bearings form the link between the Substructure and
the Superstructure and allow for lateral movement. Bearings
also have the ability to limit movement in certain directions
in order to prevent certain areas of the bridge to be
overloaded by forces, which can help limit damage to the
bridge [1]. Therefore, they are an important part of the
structure when discussing the affects that seismic energy has
on the lateral load.
Key Words—Bearings, Bridge Construction, Buckling
Restrained Braces, Earthquake Resistance, Structural Fuse
Concept, Substructure, Superstructure
BACKGROUND ON BRIDGE DESIGN
Bridges throughout the world are costly investments that
allow transportation systems to be efficient. They are built
around the general idea that they will never collapse,
however this assumption is not always correct. Whether it is
from old age, poor maintenance, or natural disasters, they
will eventually collapse. Preventing bridges from collapsing
due to natural disasters, such as earthquakes, is a
complicated process of determining what the best
technology is for the bridge, while still being cost effective.
Not only is determining the best technology for a bridge
important, but so is determining the best way to implement it
so that the resistance of a bridge to the seismic forces is
increased optimally. When a bridge is affected by seismic
energy, its three main sections, Superstructure, Substructure,
and Bearings are affected in different ways.
FIGURE 1
LOCATION OF THE SUPERSTRUCTURE, SUBSTRUCTURE, AND BEARINGS [2].
THE STRUCTURAL FUSE CONCEPT
The forces from an earthquake cause primary damage to the
substructure in areas like the piers, which in turn causes
secondary damage to the superstructure. This is because the
lateral forces from the earthquake overcome the lateral
elasticity of the columns, bearings, and superstructure [1].
However, there are ways to increase the strength of bridges
University of Pittsburgh
Swanson School of Engineering
March 1, 2012
1
Brian Sugarmann
Benjamin Tyke
by increasing the resistance to seismic energy through the
use of Structural Fuses.
The Structural Fuse Concept is the idea of absorbing
seismic energy by implementing sacrificial structural
elements [3]. The concept has been used in both bridges and
buildings. In bridges, the Structural Fuses are either built
internally or externally. The internal Structural Fuses are
built into the piers of the bridge. The external Structural
Fuses can be connected from the frame of the bridge to the
foundation or used to connect certain regions of the frame
together. Structural Fuses are designed to dissipate lateral
loads by breaking apart, which allows for less energy to
travel through the bridge, and ultimately limits the damaging
effects of the seismic energy. However, because structural
fuses are built to absorb the lateral forces by causing damage
to itself, they usually have to be replaced after a mild or
severe earthquake.
The Structural Fuses increase the lateral load of a bridge
by changing the structural composition of the piers or the
integrity of the frame. They also increase the strength and
stiffness of the pier and dissipate the majority of the seismic
energy and the hysteretic behavior, while keeping the bridge
piers elastic [4]. Hysteretic behavior is the movement or
shaking of the bridge after the seismic forces on the bridge
have ended.
as bad or worse than the ones typically reported in the
United States [5].
Another great aspect of the BRB’s is their ability to be
easily retrofitted into pre-existing structures. For bridges that
have costly maintenance or bridges that have sub-par safety
standards, the BRB’s are the perfect fix that would not only
be economically sound in reason, but also be safer in general
for the general population [6]. One of the more impressive
features of BRB’s is that when they do actually experience
seismic activity that is heavy enough to do actually structural
damage to the bridges, they can easily be repaired through
their designs, both cheaply and quickly, causing very little
disturbance to the everyday lives of people who use the
structures. Ethically, it is the duty of an engineer to hold the
safety, health, and welfare of the public through the skills
they possess [6]. Through the endorsement of BRB’s, all of
these promises are upheld.
BUCKLING RESTRAINED BRACES
One of the more prominent types of structural fuses is the
Buckling Restrained Brace (BRB). The Japanese engineer
Wakabayashi first conceptualized the concept of BRBs to
aid his earthquake prone nation [3]. The very first bucklingrestrained brace that was created used a flat steel plate
sandwiched between reinforced concrete panels. The BRBs
that first used the concept of placing steel inside concrete
left voids in between the elements to allow the seismic
energy to be dissipated through free movement, but this
caused hysteretic results. The hysteretic results left the
structures worse off than they originally would have been
without bracing [3]. Mochizuki, an engineer, tried to fill this
void between the concrete and steel with a shock absorbing
material, which worked very well in testing and in the field.
Even though this worked well in experimental use, the prices
of the BRBs with the shock absorbing material was too
costly to be used on a wide scale, which lead to the
development of an unbounded all-steel type of BRB [3].
This all steel version allowed for the same type of seismic
dissipation, and for a significantly reduced building cost
compared to the BRB with the shock absorbing material.
This BRB is even more cost effective if bolted connections
are used, which allows for easy installation and streamlined
maintenance, as well as easy access for repairs in the event
of an earthquake’s aftermath.
A BRB’s components consist of only a few major parts.
The restraining system must have a steel core, a void that is
either empty or filled with a shock absorbing material, and
an outside steel casing. The way BRB’s work shows that
there is always a fine balance between seismic energy
proofing and general stability engineering. The more the
BRBs are left unbound and free to absorb seismic energy,
the more likely they are to fail as a structural brace, which
leaves structures prone to local buckling [3]. The more focus
that is placed on giving your BRB’s general stability through
shock absorbing materials, they become more expensive, but
WHY BUCKLING RESTRAINED BRACES MATTER
When one watches the news, it is not uncommon to see news
reports of a recent earthquake’s aftermath. And very
frequently, these bridge collapses cause many injuries and
occasionally, even death. These casualties, coupled with
large sums of money for repairs and damages, make one
think about why any government would be unwilling to
make their bridge and highway codes for earthquakes as
rigid as they possibly can. In this world, there are limits to
the amount of safety precautions one can place on a structure
for it to be economically sound as an option. Although there
may be more structurally sound elements to add to a
structure that could potentially stop and accidental injury or
death, there is a certain point where the money spent would
have been better put to use on a different public project and
be more effective at saving lives [5].
BRBs are not only better suited to protect people than
systems that predate them, but they also have a strong
potential to be cheaper to produce and install if the
appropriate amount of interest is directed to the
technologies. If an appropriate amount of interest is taken in
BRB’s in a prominent country like the United States, there is
a great potential for the BRB system to become cheap
enough to install in countries that may not have the assets
nor the resources to fund research into BRB’s themselves.
Although the United States has relatively high safety
standards for bridges, and very low mortality rates from
bridge collapses, the same cannot be said for other countries
in the world that are subject to seismic activities that are just
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Benjamin Tyke
their ability to dissipate seismic energy increases. It all
comes down to the amount of money spent for stability of a
structure, not whether one type of BRB is more structurally
stable than another. Studies have shown that all steel BRB’s
may be the best BRB to use in terms of cost effectiveness
and stability, even though the lack of an actual medium to
absorb damage like concrete or similar materials leave
general stability issues unresolved [3].
TECHNICAL IMPLEMENTATION
In order to apply the BRBs to a bridge structure, engineers
must use a process to determine the effectiveness of the
BRB in a certain area of a bridge frame. They start by using
a pushover analysis of the bridge, which involves applying a
pattern force to the bridge structure [7]. These forces are
directed non-linearly as to simulate the effects of an
earthquake. Graphing the pushover analysis gives the yield
strength of the bare frame Vyf. Then the shear strength of the
bridge frame without a brace or fuse, Vi, is determined. The
shear strength test describes the strength of a material or
component against the yield or structural failure [4]. Next
the failure mode of the frame, µf, must be established. This
is the ratio of the shear strength to the results from the
pushover analysis. This ratio needs to be equal to one. If the
ratio is greater than one, the frame will fail in flexure. If the
ratio is less than one, the structure will fail in shear [7].
The average maximum permissible brace strain, εb, for a
BRB is 1.5%. However, this number changes depending on
the location of the bridge, how prone a bridge is to
experience seismic energy, and the likely magnitude of the
earthquakes the bridge will experience during its lifetime
[4]. The period, T, of the frame is measured and then used to
calculate the spectral acceleration of the bridge frame. The
spectral acceleration, Sa, is the peak or maximum
acceleration of the bridge frame under the influence of a
force [8]. Next, an engineer has to assume a spectral
acceleration for a frame that has been retrofitted with the
BRB [7]. This assumed value should be greater than the
bare frame spectral acceleration and it also needs to be
considered as a constant acceleration.
Next an estimate of the frame strength ratio is
determined, ξ. This is an estimate of the seismic demand on
the total bridge structure if the system behaved elastically to
the yield strength of the bare frame [7]. The angle at which
the BRB is being applied to the frame is calculated, using
(1), where H is the frame height and L is the frame width.
FIGURE 2
DIAGRAM OF THE MAIN COMPONENTS OF A GENERIC BRB: THE CASING,
THE CORE, AND THE VOID BETWEEN [3].
Currently, the most common BRBs are composed of a
steel core, which is encased by concrete. The concrete does
not come in contact with the steel; instead there is a small
space between the core and the surrounding concrete. This
is to allow the BRB to yield to compression, which prevents
buckling of the brace. The BRB’s steel core can be made
into different shapes, depending on the connection that is
being made and on the needed stiffness and strength of the
BRB to be effective at reducing the seismic energy [4].
Some different shapes of the BRBs can be seen in Figure 3.
There is no standard length or size of a BRB as those
measurements differ depending on many factors, which
change greatly for each individual bridge. However, in each
bridge multiple BRBs usually work together in a system to
make the bridge more resistant to the effects of the lateral
load. The system they create is called a Buckling Restrained
Brace Frame [4]. These are commonly used in buildings,
but recently they have been used in Bridges.
𝜃 = tan−1
2𝐻
𝐿
(1) [7]
Based on the values of 𝜃 and ξ, the maximum ratio
between the lateral stiffness of the BRB, αmax, and the
lateral stiffness, of the bare frame can be found, as well as
the maximum BRB strength ratio, ἠmax [7]. Lateral
stiffness is the resistance to flexing laterally and the strength
ratio of the BRB is the ratio of the base shear to the yield
base shear of the BRB [7]. The αmax and ἠmax values are
only theoretical values for the maximum BRB strength
required for the bridge and the minimum stiffness ratio
required to get the ductility for the bridge frame. Therefore,
these values can be changed later on if the stiffness of the
bridge or strength of a BRB is found to be too large or too
small [7].
FIGURE 3
DIAGRAM SHOWING THE INTERNAL STRUCTURE OF COMMON BRBS [5]
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Brian Sugarmann
Benjamin Tyke
In order to calculate the minimum required stiffness,
Kbmin, of a BRB for a structure, use of (2) is necessary.
Equation (2) uses the mimunimu ratio between the lateral
stiffness of the BRB and the lateral stiffness of the bare
frame, αmin, and the lastic lateral stiffness of the bare frame,
K f.
should be located [9]. However, these calculations are done
before the construction process so that the BRBs can be
precast before construction starts, but the final placement
cannot be done until they are tested on the bridge.
Kbmin═ αmin× Kf
In areas that are prone to seismic activity, not only are
BRB’s ethically the most logical choice for construction, but
they are also the most economically sound way of
earthquake-proofing a structure. The traditional technique
employed by construction companies in areas of seismic
activity is known as SCBF, the Special Concentrically
Braced Frame system [10]. BRB’s not only have more
favorable ductility compared to the traditional SCBF’S, but
are more economically sound, despite higher costs. This is
because the Buckling Restrained Brace Frames tend to last
longer than SCBFs. The BRB’s are also more flexible for
use in structure design, due the relatively small crosssectional area created by their use, as compared to the
relatively long unbraced SCFB lengths that result in rather
large areas. A study conducted by Dasse Design Inc. was
conducted to determine the economic viability of BRB’s
versus their SCFB counterparts [10]. The savings created by
BRB’s lies not in the braces themselves, but rather the
savings created by minimizing the need for other building
components like frame beams and pile caps. In the Dasse
Design experiment, it was shown that in a six-story building,
these savings could be as high as 34%. The study also
concluded that these saving dramatically increase as the
height of the structure increases [10]. The fact that the cost
effectiveness of BRB’s is very heavily influenced by height
and area of the structure is something that correlates very
well with bridge construction. The larger and more intricate
a bridge gets, the more money you can save by
implementing BRB’s.
IMPLEMENTATION IN CONSTRUCTION
(2) [7]
The minimum strength of the BRB,Vybmin, as seen in (3),
requires the use of the maximum BRB strength ratio, the
mass, m, of the bridge frame or pier, and the spectral
acceleration, Sa.
𝑉𝑦𝑏𝑚𝑖𝑛 =
𝑆𝑎 ×𝑚
ἠmax
(3) [7]
After calculating the minimum required stiffness and
strength, the area of the BRB connection to the pier and the
length of the BRB can be found [7]. The area and length are
necessary to determine the dimensions of the BRBs. The
area is found in (4), where the 𝑉𝑦𝑏 is the yield strength of the
BRB, which can be adjusted, and the ∅ is the angle from
(1). If the area is too large for the system to hold, the angle
∅ or the Kbmin has to be changed. However, in most cases
the angle ∅ is adjusted [7].
𝐴𝑏𝑚𝑖𝑛 =
𝑉𝑦𝑏𝑚𝑖𝑛
2×𝑉𝑦𝑏 ×cos ∅
(4) [7]
The maximum yield length, 𝐿𝑚𝑎𝑥 , of the BRB is
determined by (5). Es is the BRB elasticity modulus, which
is the BRB’s ability to be deformed elastically. If the
maximum yield length exceeds the compression length of
the BRB, then a new maximum yield must be obtained by
altering the area of the connection or the angle ∅ [7].
𝐿𝑚𝑎𝑥 =
2×𝐸𝑠 ×𝐴𝑏𝑚𝑖𝑛 ×cos ∅
𝐾𝑏𝑚𝑖𝑛
(5) [7]
If the Lmax and Abmin are appropriate for the frame or pier,
then the bridge can be retrofitted with the proposed BRB.
However, one further test must be done before it is
complete. The bridge must be tested to find if the BRB
strain, Ɛ𝑏 , is less than the average maximum permissible
brace strain, which is 1.5%. This is done in (6), where the µ𝑏
is the BRB displacement ductility.
Ɛ𝑏 =
𝑉𝑦𝑏 ×µ𝑏
𝐸𝑠
FIGURE 3
THE OUTCOMES OF THE DASSE DESIGN EXPERIMENT [10].
THE EFFECTS THAT BRBS HAVE ON
STRUCTURES
(6) [7]
Analyzing the effects that BRBs have on structures such as
bridges and buildings, reveal more about importance of this
technology. The hysteretic behavior of an unbraced bridge
frame is does not follow any pattern, which causes the
bridge to move in many different directions when being
influenced by seismic energy. Therefore the hysteretic
behavior of the unbraced frame causes more damage to
bridge [11]. With the implementation of the BRBs the
This process does not completely ensure that the BRB
will work to their maximum potential. As BRB are new to
retrofitting, many of the BRB are placed in areas based on
system of trial and error [9]. This is mainly due to the
unpredictable patterns of the seismic influence, but the
process does help engineers narrow down where each BRB
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Brian Sugarmann
Benjamin Tyke
hysteretic behavior becomes predictable and uniform. This
allows the bridge to move as one and therefore the damage
from the hysteretic behavior is limited [11].
bridge, but there is a general process that can be applied to
all bridges.
Since the BRBs can be implemented either in the pier
itself or outside of the pier, calculating the necessary
information, which is seen in the Technical Implementation
section, must be done first. In order for the BRB’s to be
implemented outside of the pier they have to be placed
underneath the Superstructure or on the outside of the pier so
that they are connected to the foundation.
FIGURE 4
THE HYSTERETIC BEHAVIOR OF A FRAME WITH A BRB [11].
The Ductility of a structure is the ability of the structure
to deform under stress from a force. When a bridge is
affected by an earthquake, the lateral load creates the stress
on the bridge. Bridges need to have a high ductility in order
to be overcome the lateral loads created by the seismic
energy. BRBs are able to give bridges high ductility because
they allow their steel core to yield to the lateral loads [11].
Another important feature of BRBs is their stiffness. The
stiffness of the BRB is its ability to resist movement caused
by forces, which would be the lateral load created from the
seismic energy. BRBs have a high stiffness which allows
them to dissipate more energy [9]. This means that there is
less energy to cause the bridge to move and therefore less
damage to the bridge. Also, the large stiffness of the BRB
allows the brace to last longer; therefore they do not need to
be replaced as frequently [9].
The deformation of the BRBs is an important
characteristic. In order for any structural fuse to be affective
it must have a large deformation value. BRBs have a large
deformation value, which provides the structure with
robustness for the uncertainties in BRB’s calculations [12].
Also, this makes bridges safer from collapse, in case there
are earthquakes larger in magnitude than what the BRBs are
designed to handle [12].
FIGURE 5
BRBS LOCATED INSIDE OF TWO PIERS [3].
Retrofitting a bridge that needs to have the BRBs on the
inside of the column is nearly impossible. In order for this
to be done, the bridge piers would have to be individually
replaced with the piers that have to BRBs already inside of
them [10]. However, to get around this, BRBs can be
attached outside of the piers and can still increase the
maximum lateral load that the bridge can handle from an
earthquake. This problem with BRBs located outside of a
pier is that they are not as effective as the in column BRBs
[12].
BRBs can be easily implemented in new bridges. They
work very well with the new type of bridge construction,
Accelerated Bridge Construction, which is being used more
frequently. This process uses prefabricated parts of a bridge
and assembles them at the construction site [13]. This
process greatly reduces the construction time and also the
cost, which is why it becoming more popular when new
bridges are being constructed [13].
The reason the BRBs work well in Accelerated Bridge
Construction is because the piers with BRBs located inside
cannot be precast on site, like common cement pier. Instead,
these columns must be manufactured beforehand, and then
shipped to the construction site [13]. The BRBs have to be
precast because of their steel and concrete composition, and
due to the complexity of the shape of the BRBs [3].
RETROFITTING AND ACCELERATED BRIDGE
CONSTRUCTION
Many bridges and overpasses in earthquake prone areas,
such as in California or other places around fault lines, that
could benefit from the implementation of BRBs. However,
these bridges must go through the process of being
retrofitted with the proper techniques to ensure they benefit
in the greatest way possible from the use of BRBs. The
equations used in the Technical Implementation section are
to determine whether a bridge could use BRBs, and if the
bridge can, it estimates where the BRB should be placed.
However, there is more to implementing the BRB’s than just
using the technical aspects and mathematical calculations.
The actual construction process varies depending on the
ADVANTAGES AND DISADVANTAGES
The BRBs offer many technical advantages compared to
other Structural Fuses in its class of seismic energy
dissipaters. The main advantage of the BRBs is that they do
not buckle because they can yield both to compression and
tension [14]. The reason why BRBs are able to yield to
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Brian Sugarmann
Benjamin Tyke
compression and tension is because the steel core of the
BRB is not bonded to the concrete casing. Another
advantage is that the BRBs have the highest ratio of
dissipated energy to added weight [14]. BRBs have a
relatively small mass compared to the rest of the bridge and
therefore the mass can be neglected from the total vertical
load on the bridge. Because the vertical load and the lateral
load are related, this leads to decreasing the lateral load from
an earthquake as compared to other structural fuses [12].
There is a direct relationship between the vertical load and
lateral load, so as the vertical load increases, the lateral load
increases. Also, the BRBs are a bracing system themselves
and therefore no additional braces are needed to connect to
the bridges structure, which helps reduce the cost of
construction of the bridge structure and easier to install [14].
The tests of BRBs have shown that they perform very
consistently, and as a result, they are being used in
earthquake prone areas throughout the world, but mainly in
the United States, Europe, and Japan [14]. Finally, the use of
BRB allows an engineer to calculate better estimates of the
seismic demands on the BRB and bridge, which allows the
engineer to find more accurate calculations of the size of the
BRB to bridge connections and of the size of the foundation
[15].
Economically, the BRBs have many important
advantages. In the long run, implementing BRBs in an
earthquake prone area would be economically beneficial as
they would be less expensive if an earthquake did occur
[14]. This is because the chance of a bridge being affected
by an earthquake, in an earthquake prone area, during its
average life span of seventy years is high [16]. If that bridge
does experience seismic energy, there will be damage done
to the Substructure and Superstructure, which would cost a
lot more money to fix or replace than replacing the BRBs.
Also, testing of the BRBs has shown that they do not need
replaced after every seismic event. Unlike other structural
fuses, the BRBs are able to withstand multiple earthquakes
without failing or the need to be replaced [6]. This helps to
save money in the long run. Furthermore, a collapsed bridge
would cause more economic problems than just replacing
the bridge. A collapsed bridge could cause certain areas of a
region to be completely cut off from transportation, which
would close down businesses and leave people stranded,
hurting the economy of the region.
There are few disadvantages of the BRBs, as many of the
disadvantages to using BRBs are due to the initial cost of
implementing them. However, there are some disadvantages
to using BRBs. As they are a newer technology in bridge
retrofitting, there is no calculation to let engineers optimize
the potential of the BRBs. Instead the calculations to
determine the location of the BRB give an estimate of where
they should be placed, the angle they should be connected to
the bridge frame, and the stiffness or ductility they should be
given [12]. Another disadvantage is that in some tests of the
BRBs, there have been cases where the BRB allocates the
seismic energy in critical areas of the bridge frame. This has
been seen to cause global failures in the system [12]. This is
a rare occurrence, but it could still potential cause significant
damage to a bridge’s Superstructure or Substructure.
However, the main problem with the BRBs is the cost of the
technology.
Even though the long term cost of
implementing the BRBs would mean less money spent on
repairing and replacing bridges, the initial cost creates an
opposition to their use. It is possible to make bridges remain
elastic and ultimately intact during an earthquake. The
problem is, it is not economically feasible for the seismic
upgrades, using the BRBs, which are necessary to make the
bridge elastic during the earthquake [12].
THE FUTURE OF BUCKLING RESTRAINED
BRACES
Further research should definitely be invested in bucklingrestrained braces. With further research, BRB’s could
become even more efficient at absorbing seismic energy, and
with any luck, become strong enough that there are no
structural repercussions when choosing to use seismic
resistant materials over ones built for general durability. If
BRBs become widely used, the amount of money needed to
be allocated to maintaining bridges will be severely reduced,
due to the sheer structural sturdiness that can be achieved.
Bridges will last even longer with the introduction of BRB’s
to mainstream construction practices, with structures that
could possibly last over a hundred years, eliminating the
need to constantly rebuild and do heavy repairs. Investment
in the concept would certainly pay off, for it is already more
economically sound to us the BRB’s in structures at this
time, and focus on mass producing the BRBs would ensure
that the prices would decrease over the time they are
produced, eventually leaving investors positive in profits.
Economic gains are undoubtedly important, but the other
ethical side of BRB’s also lends itself as support for
continued research in the technology. The amount of
personally injury and death that can be completely avoided
by the avoided structural collapses is more than enough of a
reason to invest time and money into the concept. Overall,
buckling-restrained braces are promising technology that is
completely ethically backed, in terms of engineering
dynamics, economics, and humanitarian ideals.
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Zealand Society for Earthquake Engineering Inc. [Online]. Availalbe:
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ACKNOWLEDGMENTS
We would like to thank the members of the writing center
who took time out of their schedules to give us advice in
writing our conference paper components, and the
grammatical advice they have given us. We would also like
to thank Stephen Bosela, our conference section co-chair, for
the advice that he has given us on the technical aspect of our
writing.
ADDITIONAL REFERENCES
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S. El-Bahey (2010). “Analytic Development and Experimental Validation
of a Structural-Fuse Bridge Pier Concept.” State University of New York at
Buffalo.
[Online].
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A. Fäcke1, M. Baur, and F.H. Schlüter. (2008, October 14). “Assessment of
Bridge Performance - Seismic Isolation Versus Ductility.” 14th World
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A. Ilki, F. Karadogan, S. Pala and E. Yurksel. (2009). “Seismic Risk
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