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VIBRATING BARRIERS: THE FUTURE OF STRUCTURAL DEFENSE
AGAINST EARTHQUAKES
Sujay Murthy, [email protected], Lora, 3:00, Timothy Snyder, [email protected], Lora, 3:00
Abstract— Among the many different catastrophes that have
challenged humanity, earthquakes have been some of the
most devastating. In order to protect society from these
harmful and inevitable forces of nature, engineers and
seismologists have developed and implemented various
technologies to counteract the damaging effects that they
would otherwise inflict. Some past attempts at “earthquakeproofing” buildings have included the use of steel bracing,
buffering systems, and building materials that are less prone
to fracturing.
While these methods have had some success, they are not
effective on a large scale. Due to their designs, they are
limited to protecting individual buildings rather than wider
areas containing multiple structures. In recent years,
seismologists have been studying ways to disperse or absorb
tremors before they ever contact buildings. While older
techniques of limiting damage due to seismic activity were
usually specific to individual structures, vibrating barrier
(ViBa) devices would be able to protect entire cities and
surrounding areas. The spring-like design of ViBa would
allow it to reduce the magnitude of tremors to significantly
less harmful levels.
Earthquakes continue to pose a threat to humankind.
With further testing and studies, vibrating barriers can
become a more effective mechanism of protection against
earthquakes than previous technologies, making society
better equipped for any future calamities. In doing so, ViBa
would open doors for more sustainable methods for
protecting cities, the global economy, and the environment
for generations to come.
Key Words— Earthquake defense methods, Earthquake
engineering, Infrastructure, Seismology, Vibrating barriers
FACING THE CHALLENGE OF
EARTHQUAKES
As a global community, people around the world have
endured countless natural disasters. While we have been
faced with a myriad of such catastrophes, earthquakes
continue to be some of the most devastating. According to
an article published by National Geographic, an earthquake
University of Pittsburgh Swanson School of Engineering 1
31.03.2017
of magnitude 8.0 (considered to be major by the Richter
scale) occurs at least once per year. These seismic events
have contributed to the deaths of approximately 10,000
people annually, in addition to causing widespread
destruction to infrastructure [1]. Past earthquakes have
disrupted the lives of countless communities, prompting the
need for engineers to design methods of protecting our
people, our homes, and our society.
For a method of earthquake defense to be a truly viable
option, it must consider the positive and negative effects that
its construction and implementation will cause at both the
present time and in the future. The concept of sustainable
development pertains to acting responsibly in engineering
and construction projects, working to ensure that our actions
take into consideration any potential long-range
consequences. As discussed at the Rio+20 United Nations
Conference on Sustainable Development in 2012,
sustainability involves the examination of economic, social,
and environmental concerns in all endeavors in which our
present society’s actions affect future generations [2].
In order to accomplish this goal of sustainable
earthquake defense, a variety of solutions has been
developed and implemented in order to fortify cities in ways
that protect their inhabitants and the surrounding
environment.
As outlined in an article from The
Constructor, an online civil engineering resource, some
solutions have the goal of reducing vibrations due to
earthquakes and some are designed to physically reinforce
buildings, however they are all developed with the common
purpose of protecting our infrastructure [3].
While these methods have had some success, they are
not effective on a large scale. Due to the design of these
older mechanisms, they are limited to protecting individual
buildings rather than wider areas containing multiple
structures. In recent years, seismologists have been studying
ways to dissipate the effects of earthquakes before they ever
impact cities. To do this, earthquake engineers, as well as a
group of researchers from the University of Brighton, have
studied the use of vibrating barrier (ViBa) technology for
defense against earthquakes. With further testing and
studies, vibrating barriers can become a more effective
mechanism of protection than previous technologies, making
society better equipped for any future calamities [4].
Sujay Murthy
Timothy Snyder
incident upon the base, it shakes with an acceleration that is
proportional to the magnitude of the tremor. The weight,
however, remains motionless as the spring absorbs the
energy and motion of the seismic waves. The results
generated by the seismographs, known as seismograms, are
created when the displacement of the seismograph’s base
relative to the motionless weight causes a pen to plot the
displacement over time on a rotating drum [5].
EARTHQUAKES: THE SCIENCE BEHIND
THE DISASTER
The outermost layer of the Earth’s surface, known as
the lithosphere, is made up of an intricate network of
tectonic plates, which move very slowly relative to one
another. Over the course of many years, these plates have
broken apart and collided with other plates to form many of
earth’s geographical features including mountains,
volcanoes, and valleys [5]. Collisions between plates can
also result in earthquakes and other forms of violent seismic
activity, such as tsunamis. The boundaries of tectonic plates
consist of cracked, jagged edges which are known as fault
lines. When two plates pass each other along fault lines,
friction is created and there is an increase of stress on the
rocks and other solid materials contained within.
Once the applied stress overcomes the strength of the
plates and the friction between them, the plates begin to
fracture and grind past each other. As a result of tectonic
plate slippage, a tremendous amount of energy is released in
all directions in the form of seismic waves. Since seismic
waves carry energy at various amplitudes, they will travel
through structures and cause them to shake. This event,
known as an earthquake, damages buildings and causes them
to collapse when vibration due to the tremor results in the
affected buildings being accelerated laterally and thus
displaced from their foundations. The amount of damage
done to a building depends on the amplitude of the seismic
waves.
Seismologists have developed standard methods of
measuring their magnitudes in order to more thoroughly
understand the behavior of earthquakes, a process which has
been aided significantly by the introduction of the
seismograph.
FIGURE 2 [5]
Sample seismogram showing seismograph displacement
The zigzagging lines of the seismogram shown above
represent the oscillations of seismic waves below the earth’s
surface. The amplitude of these oscillations will indicate the
location of the earthquake’s emergence, the time it occurred,
and its magnitude. A seismic wave with greater amplitude
will cause the base of the seismograph to experience
increased horizontal displacement, which is shown by waves
of higher magnitude on a seismogram.
Using data gathered from seismographs, scientists have
invented various classification systems for earthquake
magnitudes. The earliest known system, which was first
implemented in 1935, is the Richter scale. Information from
the United States Geographical Survey (USGS) states that a
whole number increase in magnitude on the Richter scale
suggests a rise in amplitude of seismic waves by a factor of
10. This logarithmic change in amplitude roughly
corresponds to a release of 31 times more energy than the
previous value on the scale [6]. The scale is a quantitative
classification of earthquake magnitudes which places them
in categories on a range of “minor” to “great” quakes [7].
Due to eventual observance of the Richter scale’s
inability to adequately record the magnitudes of larger
earthquakes, it was necessary for seismologists to develop a
new approach in classifying tremors and their strength. The
Moment Magnitude scale was soon developed, which
proved to be far more precise than the Richter scale. In
contrast to its predecessor, which only accounted for the
magnitude of earthquakes, the Moment Magnitude scale
more thoroughly assesses earthquakes by considering
additional factors such as the total area of a fault’s rupture
and the extent of slippage along fault lines. Additionally, it
accounts for seismic wave oscillations that were measured
by the seismographs. Moment Magnitude relates the
distance that a piece earth moves along its fault line with the
area of the fault’s rupture [8]. It is calculated by multiplying
FIGURE 1 [5]
Simple seismograph diagram
As shown in the figure above, a seismograph consists
of a base, a heavy weight, and a spring. The instrument’s
base is placed firmly in the ground while the weight hangs
freely on the end of the spring. When a seismic wave is
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Sujay Murthy
Timothy Snyder
the two quantities. Its goal is to relate physical
characteristics of the earthquake with its magnitude and
other physically unobservable quantities [8]. Considering its
benefits, the Moment Magnitude scale continues to be
widely used today.
Communities continue to feel the effects of an
earthquake in its aftermath. Areas surrounding an
earthquake’s epicenter typically experience smaller tremors
known as aftershocks which follow as direct results of the
primary earthquake. An aftershock can occur days, or even
weeks, after an earthquake initially took place, causing
serious infrastructural damage which regularly results in
thousands of people losing their lives. To exacerbate the
situation, severe flooding, fires, mudslides, and avalanches
usually accompany earthquakes. These events complicate
the rescue efforts of first-response teams and disaster relief
organizations and make it much for difficult for people
fleeing danger to take refuge.
The failure of structural integrity in various structures
causes many fatalities during earthquakes. Due to poor
building practices or a lack of protective measures, buildings
often collapse when exposed to minimal amounts of
acceleration caused by earthquakes. According to Penn State
University’s Earthquake Seismology Department, the 1908
Messina Earthquake in southern Italy resulted in the death of
over 200,000 people, more than half of which perished due
to the collapse of largely unreinforced structures that were
found throughout the region [9]. In 1994, Los Angeles,
California was hit by the Northridge earthquake, one of the
worst seismic events that the city has experienced in its
entire history. The majority of the damage and death that
occurred was caused by the collapse of structures in a
Northridge apartment complex that were insufficiently
reinforced [10].
As illustrated by these and countless other tragedies,
the majority of people who die during earthquakes are killed
by buildings that collapse due to a lack of protection against
seismic activity and poor construction practices. In order to
prevent similar disasters from so easily taking the lives of
thousands in the future, civil engineers must dedicate effort
to developing effective mechanisms of earthquake defense.
Necessary factors which must be considered when
designing earthquake-proof buildings is the advantages of
using more durable materials during the construction process
in place of less-suitable alternatives. A primary
characteristic of building materials that earthquake engineers
are concerned with is their ductility. Ductility, a property of
most metals, is the ability of a material to be stretched under
tension. Taking this characteristic into consideration allows
for a determination of those building materials that are least
likely to fracture under the forces caused by earthquakes.
Substances such as glass, brick, and concrete are extremely
brittle and therefore are unable to withstand the stress and
strain that they are exposed to during an earthquake. As a
result of this lack of ductility, buildings that are constructed
primarily from these materials are very prone to collapse
during major seismic events [11].
In contrast, steel is more ductile and is thus a much
more effective option for reinforcement of infrastructure.
Steel, as used in modern construction, is found in a variety
of forms such as flat plates, rods, and beams. Buildings
which have steel integrated into their foundations and
structures are much more flexible than those that do not, and
are thus able to slightly bend under stress rather than simply
yielding.
STANDARD METHODS OF EARTHQUAKE
DEFENSE
FIGURE 3 [12]
Steel Moment Frame
As aforementioned, many of the fatalities that occur
during earthquakes have been attributed to the failure of
buildings to maintain their structural integrity. While it is not
feasible to entirely prevent future disasters, engineers can
better protect communities across the globe by “earthquakeproofing” infrastructure with a variety of defense methods
and technology. Civil engineers have employed various
earthquake defense techniques since the mid-1900s, some of
the most common of which being strengthened building
materials, base isolation systems, and damping devices [11].
Displayed in the image above, the steel moment frame
construction design is intended to make buildings more
earthquake-resistant by reinforcing their main structure with
an array of steel beams. However, events such as the
Northridge earthquake have revealed flaws in steel
reinforcement techniques, despite their theoretically
“earthquake-proof” design. Though certainly stronger than
structures that are primarily composed of brick or glass,
steel-reinforced buildings have shown varying degrees of
success when faced with major earthquakes [10].
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Another technique which earthquake engineers have
implemented for the protection of infrastructure is the base
isolation system. Base isolation involves the installation of
substantial amounts of physical padding between a structure
and its foundation. This isolation padding, or bearing pad,
can be produced from a variety of materials which are
designed to be capable of withstanding massive vertical
force while still being flexible when affected by horizontal
displacement forces [3].
effects of large tremors. Engineers have developed damping
devices, which are integrated into a building’s foundation
during initial construction and are intended to reduce the
chronic damage done on structures by subterranean
shockwaves.
The various types of damping devices can largely be
categorized into four major divisions: friction dampers,
metallic dampers, viscoelastic dampers, and viscous
dampers. These different varieties of damping systems
employ either a solid material or a viscous liquid. Dampers
work much like shock absorbers, whose purpose is to absorb
the energy of seismic waves prior to their collision with the
building’s foundation. The energy that is absorbed by the
dampers forces motion in the opposite direction of the
applied force and thus counteracts the seismic waves. As a
result, buildings that are protected by damping systems
oscillate when experiencing acceleration due to seismic
waves, rather than simply fracturing under the immense
force [3].
FIGURE 4 [3]
Comparison of ideal reactions between Fixed-Based
Structures and Base Isolated Structures
VIBRATING BARRIERS: PROTECTING
CITIES AT THE SUBTERRANEAN LEVEL
The above figure shows the horizontal displacement of
structures that occurs, comparing buildings which employ
base isolation systems with those that are directly contacting
their foundation. As the seismic waves of the earthquake
apply a force on the building in one direction, the inertia of
the building causes it to move in the direction opposite to
that of the applied force. The fixed-base building is damaged
when it skews into a parallelogram shape, as a result of its
inertial resistance to the force of the earthquake.
A building that has a base-isolation system
incorporated into its design maintains its rectangular shape
when exposed to the same force that majorly deforms fixedbase structures. The bearing pads at the base of the isolated
structure are deformed, however the building itself is not
deformed during the process. The insulating material within
the bearing pads contributes to this extreme reduction in
acceleration by dissipating the kinetic energy of the tremors.
This absorbed kinetic energy is released in the form of
thermal energy and thereby reduces the magnitude of
vibrations that enter the building. Base-isolation systems
increase the period of the vibrations that cause the building
to be displaced, which reduces the magnitude of acceleration
of the building to approximately one-fourth of its unbuffered
value [3].
Damping devices are another alternative method of
defending buildings during seismic events, whose goal is
similar to that of base-isolation systems. While both methods
seek to absorb the force that would otherwise be transferred
directly into buildings, damping systems dissipate the energy
of seismic waves to a much greater extent. While baseisolation systems have proven that buildings that are
insulated from their foundations experience less damage
during an earthquake, they are not adequate for limiting the
Despite the advantages of these technologies and
building methods, they have repeatedly failed at sufficiently
protecting infrastructure. In an attempt to prevent further
tragedies, civil engineers and other research teams have
recently been studying the use of ViBa technology as a more
effective solution for defense against earthquakes.
Pierfrancesco Cacciola and Alessandro Tombari, two
members of a research team from the University of
Brighton, explained in their 2015 article that the purpose of
ViBa is to minimize the effects on buildings that arise due to
earthquakes and other seismic activity [4].
In its design, ViBa greatly considers the effects of
Structure-Soil Interaction (SSI) as well as Structure-SoilStructure Interaction (SSSI). The basis of SSI involves
analyzing the interface between the ground and individual
buildings that occurs as a result of seismic activity [13]. In
their 2011 article in the journal Soil Dynamics and
Earthquake Engineering, Menglin Lou, Huaifeng Wang, et
al explained that SSSI is “the dynamic interaction problem
among the multi-structure system through soil-ground.”
SSSI studies the effects that the ground has on a cluster of
buildings, and vice versa, when under the influence of
seismic events such as earthquakes [13].
In their article regarding the structure and function of
vibrating barriers, Cacciola and Tombari explain that ViBa
consists of a solid, underground foundation that surrounds a
spring-like oscillator [4]. The device’s foundation could be
made out of concrete, however according to Cacciola it also
is able to be made from waste material produced by other
construction projects or the soil from an excavation site [14].
Producing enough concrete to be used for the ViBa’s
base would lead to the release of many different pollutants.
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Sujay Murthy
Timothy Snyder
The process of making concrete produces large quantities of
waste material and hazardous gases such as carbon dioxide
and sulfur dioxide, which would result in the contamination
of water sources and the release of destructive and toxic
substances into the atmosphere [15]. As the ViBa device
requires a massive frame in order to securely anchor the
oscillator, producing it from concrete would result in many
of these contaminants being released into surrounding
ecosystems, greatly endangering animal and human life.
However, Cacciola says that using recycled waste
materials or excavated soil for constructing ViBa’s
foundation can eliminate the generation of new pollutants
that would be caused by the production of massive amounts
of concrete or other similar materials [14]. In doing so, ViBa
would ensure that efforts to protect cities from earthquakes
are sustainably protecting ecosystems from preventable
harm by pollutants.
As per its proposed setup, the vibrating barrier device
would be placed below ground in close proximity to a
cluster of buildings, whereas other, more standard, methods
of earthquake defense typically have been integrated into
one particular building’s structure.
FIGURE 6 [4]
Prototype of ViBa device
The image above displays a prototype of a vibrating
barrier system. As shown, the oscillator in ViBa will vibrate
when seismic waves are incident upon it, which will result in
the dissipation of tremors before they are able to interact
with the building and the ground directly below it.
The intention of vibrating barriers is that they will
greatly limit, if not eliminate entirely, the effects of SSSI
that occur during earthquakes. In theory, any motion of the
ground due to tremors and shockwaves would be absorbed
or dispersed by the ViBa device, rather than being
transferred into the surrounding buildings. In order to meet
this challenge, ViBa’s oscillating design would essentially
absorb seismic waves and thus greatly minimize the
magnitude of earthquakes [4].
The ViBa device is designed to limit the displacement
of buildings due to earthquakes or other seismic events
according to the equation
𝑼𝒓,𝐦𝐚𝐱
= 𝐦𝐚𝐱(𝑼𝒊 − 𝑼𝒇,𝒊 ) ,
𝒊
in which Uir,max is the maximum displacement of a certain
building in the network. In this equation, the displacement
is derived from structural parameters such as the mass of the
ViBa (mViBa), and the stiffness (kViBa) and damping (ηViBa)
properties of the vibrating barrier’s foundation and oscillator
[4].
Combining a structure with ViBa has been shown to
significantly reduce the acceleration, and thus force, that the
building experiences due to an earthquake.
FIGURE 5 [4]
Basic arrangement of the ViBa device relative to
adjacent buildings
The above diagram displays the setup of the ViBa
system, where Ug is the displacement of the ground due to
tremors. The device would be placed at the subterranean
level, theoretically absorbing seismic activity before it ever
comes into contact with the buildings themselves. Since it is
not integrated into an individual structure, a single vibrating
barrier is capable of protecting a network consisting of
multiple different buildings [4]. If implemented in cities, a
single vibrating barrier has the potential to better protect a
larger area than that which is currently protected, less
effectively, by current methods of earthquake defense.
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Sujay Murthy
Timothy Snyder
COMPARING VIBRATING BARRIERS TO
PAST ATTEMPTS AT INFRASTRUCTURAL
PROTECTION
Although every method of protecting infrastructure
from earthquakes has both advantages and disadvantages,
ViBa has the potential to be significantly more successful
than past methods. Its widespread use would greatly
improve, and simultaneously simplify, the process of
sufficiently protecting our communities from the threat of
seismic activity.
One of the most significant benefits of using ViBa as
an alternative to past methods of structural defense is its
capability to serve as a protective barrier for multiple
buildings that are in proximity to each other. While
traditional methods, such as the use of stronger varieties of
concrete in construction or the installation of steel-reinforced
walls, have had to be incorporated into each individual
structure, the ViBa system would be able to protect an entire
city with only a few vibrating barrier devices.
As the ViBa device simply consists of an oscillator
within a subterranean foundation that is located apart from
buildings, it would not have to be installed at the time of
construction of buildings. This would particularly benefit
cities in which there are important historical buildings and
other older structures. Although many of these buildings
likely will have been constructed without any significant
defense against earthquakes, ViBa’s unique, detached design
would permit the protection of such structures, without
requiring any renovation to the edifice itself.
In addition to being more effective than physical
reinforcement methods, ViBa will prove to be an
advantageous alternative to buffering systems which also
serve to reduce vibrations that arise due to earthquakes and
other varieties of seismic activity. Although they have
shown success when implemented during the construction of
new buildings, using these older buffer technologies on
preexisting buildings would require extreme overhaul of the
structure, due to their need to be heavily integrated into the
building’s foundation in order to function properly [2].
As well as being more readily installable than other
damper devices, ViBa has the ability to be configured in
such a way so as to dampen all of the components of a
seismic wave, whereas past damping technology has not
been entirely successful in this area [2].
While the aforementioned standard methods of
earthquake defense aim to maintain the structural integrity of
a building affected by seismic waves, ViBa’s objective is to
prevent structures from ever experiencing the full effects of
earthquakes. Through its dissipative functions, ViBa will be
able to reduce seismic waves to a relatively miniscule
fraction of their original strength before they encounter the
nearby infrastructure.
FIGURE 7 [4]
Comparison of effects on a building with and without the
use of ViBa
The figure above displays a model building’s
acceleration as a function of time when under the influence
of simulated earthquake-like motion, both with and without
coupling with the ViBa system. As aforementioned, there is
a drastic reduction of the acceleration of a building due to
base motion of circular frequency 22.62 rad/s (simulated
seismic activity) when ViBa is used compared to when it is
not. For the case that is not protected by ViBa, the
acceleration of the structure was recorded to be very close to
20 m/s2 (approximately twice the acceleration due to earth’s
gravitational pull) [4]. An acceleration of this magnitude has
great potential to cause extensive destruction and loss of life
if it were to be incident upon an urban building. However,
when the ViBa system is used to protect the same structure,
the acceleration of the system is limited to a very low
intensity. Despite an initial spike in the acceleration shortly
after the “tremor” began, Cacciola and Tombari’s results
indicate that ViBa was shown to limit the acceleration of the
building-barrier system to a significantly less harmful level,
with a maximum of 87% acceleration reduction when using
this prototype [4].
Although not widely used at the present time because
they are still in the early stages of development, vibrating
barriers can excel as a defense against earthquakes.
Researchers from the University of Brighton who have been
studying its efficiency with prototypes on a smaller scale
believe that ViBa is capable of reducing violent seismic
activity by 40 to 80 percent [16]. This reduction of tremor
magnitude to a much less harmful level ensures its
effectiveness in preventing many injuries and deaths.
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Sujay Murthy
Timothy Snyder
A fringe benefit of using ViBa is that it also offers
protection from seismic waves caused by human actions.
Although the vibrations caused by mining, transportation
systems, and industry typically have much lesser magnitudes
than those caused by earthquakes, chronic exposure to even
moderate tremors will weaken a structure’s foundation over
time. With the ability to dissipate any vibration that takes
place in the ground, ViBa would protect buildings from
these regular occurrences and thus increase the longevity of
our infrastructure [17].
Benefits provided to society by the effective
earthquake defense of ViBa go beyond solely physical
protection to also the protection of our economy and
environment, reducing costs of repair and negative impacts
on the population [18]. In 2010, an 8.8 magnitude
earthquake struck Chile’s central region and had devastating
effects that were felt throughout the country. In addition to
the tragic deaths of hundreds of people, this event took a
great toll on the Chilean economy. As it struck some of
Chile’s most heavily populated and economically productive
areas, the nation suffered significant financial losses.
According to a 2010 article from the London-based
newspaper The Economist, rebuilding the infrastructure that
was destroyed by the quake was estimated to cost about 20%
of Chile’s 2009 gross domestic product (approximately $30
billion) [19].
The financial impact that this earthquake dealt on Chile
further shows the need for an effective method of earthquake
defense that is offered by ViBa. Along with preventing loss
of life as buildings collapse, equipping cities with this more
effective technology better protects economies for both
current and future generations. While some earthquake
defense technologies may have been used in Chile prior to
the 2010 earthquake, ViBa’s ability to reduce the
magnitudes of seismic waves more effectively than other
methods may have minimized the widespread damage and
loss of life that occurred.
ViBa technology has many clear advantages over
other, more common varieties of earthquake defense,
however, it is not completely lacking flaws. One primary
disadvantage of the vibrating barrier is that to be effective, it
must have a very large mass [4]. Were it not incredibly
massive, withstanding and suppressing the force acting upon
the system due to an incident shockwave would be nearly
impossible. In order to sufficiently defend against vibrations
caused by earthquakes, the ViBa system’s mass must be at
least 50% of that of the building that is being shielded [20].
Due to the great mass requirement, it would be necessary to
use a recycled source for the foundation, as previously
mentioned, in order to make the production of ViBa more
cost effective and environmentally sustainable on a wider
scale.
As previously stated, vibrating barriers can reduce the
magnitude of vibration that is transferred into buildings due
to seismic waves by tremendous levels. If the ViBa device
was free of any damping effects, and thus allowed to
oscillate with as high of a frequency as would be necessary
for vibration reduction, it would be able to reduce the
relative displacement of structures due to seismic events by
99.05% [4]. However, the internal oscillator would need to
move at an extremely rapid pace in order to accomplish this,
which would ultimately lead to the failure of the ViBa’s
mechanisms. In order for ViBa to maximize the reduction of
structural displacement, it is necessary to optimize certain
characteristics of the system.
FIGURE 8 [4]
Structural Displacement Reduction Factor relative to
mass ratios of ViBa
The graph above displays the degrees to which
different mass ratios of the ViBa device dictate the amount
that structures are displaced as a result of earthquakes. In
order to make vibrating barriers as effective as possible, it is
necessary that engineers and seismologists do further
research regarding these devices. To maximize the
displacement reduction, researchers working with ViBa must
find the optimal mass for the system along with determining
ideal values of damping and stiffness of the oscillator [4].
Once these studies and tests are completed and ideal
parameters are calculated, vibrating barriers will innovate
the field of earthquake engineering.
THE VERDICT ON VIBRATING BARRIERS
Due to the high frequency of earthquakes that occur
throughout our planet each year, it is imperative that we take
substantial measures to effectively protect our cities from
seismic events. The need for a new means of protection is
evident given the insufficiencies of previously used
technology. Despite having some amount of utility, the lone
use of structural reinforcement or buffering devices has
proven to be inadequate for protecting our communities.
While each method of earthquake defense has both
beneficial and disadvantageous aspects, it is certain that
further development of vibrating barrier technology would
be a worthwhile endeavor.
As the damage done to buildings in the event of an
earthquake arises as a direct result of SSI, it directly follows
that an effectual method of combatting seismic waves
accounts for these interactions. In doing this, such a
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Timothy Snyder
[8] “What is Moment Magnitude?” Esg Solutions. Undated.
Accessed
03.02.2017.
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[9] C. Ammon. “Earthquake Effects.” Penn State Earthquake
Seismology.
08.01.10.
Accessed
03.02.2017.
.http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/Intro
Quakes/Notes/earthquake_effects.html
[10] “Northridge Earthquake.” Southern California
Earthquake Data Center, Chronological Earthquake Index.
Undated.
Accessed
03.03.2017.
http://scedc.caltech.edu/significant/northridge1994.html
[11] “Stubborn Structures.” UMich.edu. Undated. Accessed
03.31.2017. http://dme.engin.umich.edu/stubbornstructures/
[12] K. Luttrell. “ConXtech’s ConXL™ Bi-Axial Steel
Connector has Been Formally Approved as a Special
Moment Frame (SMF) Connection by the American Institute
of Steel Construction (AISC).” Prweb.com. 04.14.2011.
Accessed
03.02.2017.
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89.JPG
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mechanism would exploit the physical interactions that
occur during seismic events and manipulate them in such a
way as to reduce the acceleration of buildings due to
subterranean shockwaves. ViBa is designed to exploit the
principles of SSI and SSSI to significantly reduce the
magnitude of vibration that is transferred into the buildings
themselves [4].
ViBa’s unique placement in an external location
relative to the buildings that it is defending makes it a more
efficient system. Rather than being solely capable of
protecting an individual building to which it is physically
attached, this system can serve as a protective barrier for a
network of buildings, which significantly simplifies the task
of making cities safer for their inhabitants.
While ViBa is not a faultless solution, it certainly has
potential to revolutionize the field of earthquake
engineering. Based on recent analysis of testing done on
prototypes of this system, ViBa technology will greatly
simplify the process of protecting cities against future
earthquakes and other seismic events, without sacrificing
utility, sustainability, and performance. If the civil
engineering community pursues the vibrating barrier as a
viable solution for earthquake defense, the threats imposed
by seismic events can be more effectively minimized than
ever before.
SOURCES
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Constructor.
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device for the passive control of structures under ground
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https://earthquake.usgs.gov/learn/kids/eqscience.php
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an Earthquake.” USGS.gov. 1989. Accessed 01.10.2017.
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8
Sujay Murthy
Timothy Snyder
https://nextcity.org/daily/entry/earthquake-protection-testviba
ACKNOWLEDGEMENTS
Researching our topic and writing our conference paper
has been a gargantuan task, and we would be remiss if we
did not thank the people who aided us in the process. Thank
you to Dr. Pierfrancesco Cacciola for taking the time to
detail to us some of his findings from his research of
vibrating barrier technology. Thank you to Dan McMillan
from the writing center and our writing instructor Michael
Cornelius for each assisting us with understanding the
assignment and helping us improve our writing skills. We
also thank our co-chair, Sara Zahorchak, who gave us
guidance based on her past experiences as a freshman
engineer and offered suggestions regarding our paper.
Finally, we thank our parents and family members for
providing us with their consistent love and support in all our
lives’ ventures.
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