Session C7
Paper #121
Disclaimer — This paper partially fulfills a writing requirement for first year (freshman) engineering students at the University
of Pittsburgh Swanson School of Engineering. This paper is a student, not a professional, paper. This paper is based on
publicly available information and may not be provide complete analyses of all relevant data. If this paper is used for any
purpose other than these authors’ partial fulfillment of a writing requirement for first year (freshman) engineering students at
the University of Pittsburgh Swanson School of Engineering, the user does so at his or her own risk.
CARBON FIBER ELEVATOR CABLES: ENABLING INCREASED
STRUCTURE HEIGHT
Alex Enzman, [email protected], Budny, 10:00, Nathanael McGuire, [email protected], Budny, 10:00
Abstract—Traditional steel elevator cables have an effective
height ceiling that limits their use in buildings over 500m tall,
as they become increasingly energy inefficient and
mechanically unstable as the height increases. Additionally,
problems arise with the steel cables due to their resonance
frequency, as elevators in some skyscrapers must be shut down
during high winds. To counteract these problems, carbon fiber
has been introduced as a potential replacement for traditional
steel wire in elevator cables, an advancement that promises to
help cities continue to build taller structures in a safe and
environmentally friendly way.
Carbon fiber has long been known to possess highly
desirable properties, such as a high tensile strength in
proportion to density. Replacing steel with carbon fiber in
elevator cables increases the potential height of skyscrapers
through its greater durability, higher energy efficiency, and
reduced resonance during high winds. The Finnish company
KONE has demonstrated this with Ultrarope™, the first
iteration of a commercial carbon fiber elevator cable.
The benefits of carbon fiber elevator cables will be
analyzed using material property comparisons with steel (e.g.
tensile strength). In addition, the specific design of current
carbon fiber cables using the KONE Ultrarope™ patent,
which provides diagrams and schematics, will also be
thoroughly examined. Through compiling and analyzing
relevant information and specifics available for Ultrarope, the
goal of this paper is to determine the cable’s viability in the
commercial market. The authors hypothesize that carbon fiber
is beneficial for elevator cable technology because its
implementation will promote increased energy efficiency,
durability, and stability.
fall behind. Traditional steel elevator cables fall victim to their
own weight in elevator shafts spanning over 500m, where they
are susceptible to necking and breaking, and become
increasingly energy inefficient as the height increases [2].
Additionally, problems arise with the steel cables due to their
resonance frequency, as elevators in some skyscrapers must be
shut down during high winds [3]. To counteract these
problems, carbon fiber has been introduced as a replacement
for traditional steel wire in elevator cables, an advancement
that promises to help cities continue to build taller towers in a
safe and environmentally sustainable way [2].
Carbon fiber has long been known to possess highly
desirable properties, such as a high tensile strength in
proportion to density. Replacing steel in elevator cables has
been demonstrated to increase the potential height of
skyscrapers through its greater durability, higher energy
efficiency, and reduced resonance during high winds [4].
Ultrarope, a current example of a commercial carbon fiber
elevator cable, is to be used in the construction of the world’s
tallest structure, the Kingdom Tower in Jeddah, Saudi Arabia
[5]. Patented by KONE, Ultrarope is the first iteration of
carbon fiber elevator cables; it shows the potential to raise the
altitude limit of tall structures, and provides a means to create
more energy sustainable cities. Ultrarope proves to be a
significant advancement in the capabilities of elevator
technology [4].
This paper will analyze the benefits of carbon fiber
elevator cables through several perspectives. First comparing
properties of the cable materials, such as their specific
strength, tensile strength, and resonance frequency, utilizing
known scientific information, as well as data from technical
journals. It will then thoroughly analyze the specific design of
current carbon fiber cables using the KONE Ultrarope patent,
which provides diagrams and schematics. Finally, it will
present how this information will be useful in determining that
carbon fiber is beneficial for elevator cable technology, since
its implementation will promote increased energy
sustainability, durability, and stability.
Keywords—Carbon fiber, Composites, Matrix, Polyurethane,
Resonance, Ultrarope™, Tensile strength
RAISING THE ROOF
As populations continue to grow rapidly, many agree that
building cities vertically will help save urban areas from
extensive traffic, while helping lower carbon emissions [1].
However, with the increasing height of accommodating
structures, the current technology for elevator cables begins to
University of Pittsburgh Swanson School of Engineering
03/03/2017
PROPERTIES OF STEEL CABLE VS.
CARBON FIBER CABLE
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Alex Enzman
Nathanael McGuire
are increased, the functioning capability of steel rope likely
surpasses that of carbon fiber composite rope.
Material Properties
Known data clearly states that, for any given weight,
carbon fiber is much stronger than steel, which supports our
reasoning for implementing carbon fiber cables instead of
traditional steel cables [4].
Most steel used for cabling has an ultimate tensile
strength of around 2000 MPa (300 ksi) [6]. While this number
is relatively high, it must be associated with its density, which
is 8.0 g/cc, which results in a specific strength (tensile strength
divided by density [N-m/kg]) of approximately 2.5x105 Nm/kg. This data can then be compared with the properties of
carbon fiber. Continuous carbon fiber has a tensile strength of
4900 MPa—well over twice that of steel [7]. In addition, its
density is only 1.8 g/cc, resulting in a specific strength of
2.7x106 N-m/kg, nearly 11 times the specific strength of steel.
These numbers indicate that, given steel rope and a
carbon fiber rope of equal lengths and diameters, the carbon
fiber rope will have less mass and greater strength. This is
important because it clearly shows that carbon fiber allows for
elevator cables with high strength and low weight. This, in
turn, becomes significant not only when considering structure
height, but also energy usage, which will be discussed further
on.
Audio-mechanical Properties
In addition to simple mechanical limitations, the
resonance properties of steel cables have also become a
problem in tall structures. High winds cause buildings to sway,
with the effect becoming significant especially in extremely
tall structures. Occasionally, this frequency at which the
building sways due to the wind matches the natural resonance
frequency of the steel elevator cables. When this occurs,
elevators must often be stopped due to turbulence until the
winds subside [3]. Carbon fiber elevator ropes provide a
potential method for counteracting this issue.
The equation relating wave speed along a cable and the
wavelength is given by,
𝑇
√ = 𝑓𝜆
𝜇
where T is the cable tension,  is the linear density, 𝑓 is
frequency, and  is the wavelength [17]. The above equation
simplifies to
Considering the Effects of a Matrix
√𝑇
=𝜆
𝑓 √𝜇
Keeping this data in mind, it is also important to analyze
the mechanical properties of the other materials that
accompany carbon fiber rope. The leading iteration of carbon
fiber rope is Ultrarope; it is a composition of multiple material,
specifically a carbon fiber reinforced composite [8]. Each
individual rope is comprised of carbon fiber within a flexible
and high-friction polymer matrix (e.g. polyurethane).
According to KONE, the resin or plastic matrix optimally
binds and separates each individual fiber, preventing damage
from friction and mechanical wear while keeping them
oriented to the direction of the load [8]. This results in a
significantly longer service life. Also, a woven fabric is
incorporated into the outside of the matrix to ensure that,
should cracking of the core occur, the matrix would remain
intact, thereby increasing its durability [8].
While the main structural component of the rope is its
carbon fiber core, the matrix can also have an effect on the
overall integrity of the rope. Carbon fiber itself has an
extremely high melting point (>6000 F), but most resin
matrices experience failure at around 250 F [9]. In comparison,
steel rope has a working temperature limit of about 750 F [10].
Thus, in a situation (e.g. a structure fire) where the temperature
inside an elevator shaft reaches a critical temperature (~250
F), steel has the potential to outperform a carbon composite
rope, due to the degradation of its matrix.
In perspective, the net effect of the matrix on the carbon
fiber rope is that under normal working conditions, carbon
fiber rope will mechanically outperform steel. As temperatures
Assuming for the purposes of this paper, that tension and
frequency would be the same for any given rope, the above
equation reveals that the resonance frequency  varies with
1/√𝜇. This means that the ideal wavelength for resonance will
decrease with increasing linear density.
Relating this data to elevator cables, this simple math
implies that ropes having a lower linear density will have a
longer natural resonant wavelength, and, thus, will be able to
be used over longer distances without resonating. As was
stated previously, carbon fiber has a density of about 22% of
the density of steel. This means that based on these equations,
carbon fiber will be less prone to adversely resonate than steel
for a given height because of its much lower mass per unit
length. Thus, carbon fiber is able to be used more effectively
in extremely long elevator cables compared to steel.
ANATOMY OF THE CABLE
Understanding the design and composition of Ultrarope
is critical to establishing it as a superior means of elevator
travel. KONE’s elevator cable design and development are
examined and evaluated through looking at the patent
application for Ultrarope. This application includes exact
blueprints and schematics of the elevator systems [8]. A
schematic of a generic elevator system is displayed in Figure
1 [11].
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FIGURE 2 [7]
Side by side comparison of Ultrarope (stacked-left) and
traditional steel rope (braided-right).
Also seen in Figure 3 are grooves, labeled G, that
separate each load bearing section [8]. These grooves only
measure 0.5mm in depth, but they act as an important
component of the cable, as they provide a degree of flexibility,
while improving its mechanical properties [8]. These grooves
are implemented into the cable through pultrusion, where
fibers are saturated in polyurethane, heated, and molded into
their desired shape [8]. The primary load bearing “P” sections
are coated in epoxy due to its ability to reinforce and bind the
carbon fibers, while the outer region is coated in polyurethane
due to its high coefficient of friction and resistance to wear [8].
The two sections are then coated in a final layer of
polyurethane, labeled “C” in figure 3 [8]. The high coefficient
of friction of polyurethane helps eliminate slippage as it passes
over the hoisting machine shown in figure 1 [11].
Damage Sensing
FIGURE 1 [7]
Schematic of elevator system.
KONE also has constructed mechanisms and sensors
within Ultrarope to monitor the integrity of the cable. Each “P”
section of the cable has a sensor fiber and reference fiber
bundle passing through its center [8]. The reference bundle is
installed such that no structural strain from the elevator load
can be felt on it, and it is then used as a base comparison of the
amount of strain felt on the sensor fibers [8]. These sensor
fibers are then connected to a condition monitoring device
labeled “R” in figure 3 [8]. This device is a small computer
containing, “a laser transmitter, receiver, timing discriminator,
a circuit measuring a time interval, a programmable logic
circuit and a processor,” which are used to monitor the wear
on the cable [8]. This built-in durability sensor puts Ultrarope
bounds ahead of current cable technology, bypassing the need
for routine maintenance checkups.
Mechanical Components
As seen in Figure 2, Ultrarope has a rectangular crosssection, unlike traditional steel cable’s circular profile [11].
This design can be further analyzed in Figure 3, where the
components of a slice of Ultrarope are displayed in a cross
section [8]. Ultrarope is comprised of four main composite
sections, labeled P1, P2, P3, and PM [8]. These sections are
made of carbon fiber, reinforced in an epoxy resin matrix [8].
These four sections act as the primary load-bearing component
of the cable, with most of the gravitational force and tensile
stress acting on these sections parallel to the orientation of the
carbon fiber [8]. It is possible to increase the number of these
load-bearing sections, which gives Ultrarope the capability of
adjusting the cable strength according to the elevator shaft
height [8]. This option gives KONE the ability to optimize the
cable strength to weight ratio for each elevator shaft.
Analyzing the Overall Design
Ultrarope is designed both to outperform and outlast
current cable technology [12]. The distinct sections of carbon
fiber allow for tremendous strength and flexibility that exceed
the capabilities of steel wire cable [8]. Also, its high friction
polyurethane coating allows it grip hoisting devices to a
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Nathanael McGuire
greater extent than its traditional counterparts [8]. Finally, the
inclusion of cable wear sensors places Ultrarope as
mechanically and technologically superior to current elevator
cable [8].
benefit society both through their civil engineering
implications and energy efficiency [13].
Structure Height
It has already been stated that carbon fiber would allow
for increased structure height through decreasing the restraints
caused by elevator cable length limit. Thus, a clear societal
impact is that, due to its strength and resonance properties,
buildings could be constructed to a greater height with
continuous elevator shafts, meaning few transfers, if any. An
example of this the Kingdom Tower, which will have the
longest continuous elevator in the world, with a height of 1 km
[5]. In contrast, the current tallest building in the world, the
Burj Dubai in the United Arab Emirates, uses traditional steel
rope, and requires several elevator transfers to reach upper
floors [5]. Thus, it is apparent, from material property data and
from demonstration, that carbon fiber elevator rope
technology allows for simplified construction of taller
structures. This would evidently have the potential to cause an
increase in the average height of new structures, and, hence,
could increase usable space in metropolitan areas, allowing for
improved traffic flow and lower pollution [1].
FIGURE 3 [6]
Elevator hoisting mechanism using Ultrarope.
SOCIETAL IMPACT AND
SUSTAINABILITY
The societal impact of carbon fiber elevator rope
technology and concerns about its sustainability are indelibly
intertwined. Sustainability is defined in several distinct ways:
First, as “involving methods that do not completely use up or
destroy natural resources.” Second, something sustainable has
the “ability to last or continue for a long time [15].” Both of
these definitions become useful in determining whether carbon
fiber elevator technology will be viable. They imply that, for a
technology to be practical and beneficial, its implementation
must not create an eventual loss in energy efficiency, savings,
or environmental integrity. Any of these conditions would
cause the eventual costs to outweigh the potential benefits,
leading to a condition that is unable to continue indefinitely,
and, thus, is not sustainable. This important concept controls
the parameters of what technology could have a beneficial
societal impact.
Examining this technology, then, in light of these
considerations is key to determining whether carbon fiber
cable technology would be both sustainable and beneficial to
society. The following subsections detail and analyze the
impact this technology could have in four specific ways,
namely, structure height, energy efficiency, cost, and carbon
footprint.
To effectively investigate the actual effects that
implementing carbon fiber rope into elevator cables would
have on society, we will focus our analysis on Ultrarope, the
leading iteration of carbon fiber in this use. This will provide
a real-world cost-benefit analysis. The possibilities of
Ultrarope’s impact extend beyond its mechanical superiority
to steel cable. Through understanding Ultrarope’s practical
applications and societal effects, its true value can be
measured. Carbon fiber elevator cables offer the potential to
Energy Efficiency
Reducing energy consumption is a huge drawing factor
for Ultrarope, especially in taller buildings such as the
Kingdom Tower [5]. The much lower density of carbon fiber
compared to steel results in less mass having to be moved by
the elevator’s hoisting device. By reducing the amount of
moving mass, Ultrarope is able to significantly decrease the
amount of energy consumed per elevator trip.
The data in the following paragraph examines the energy
savings and mass reduction statistics provided by KONE.
Figure 4 clearly expresses that as the height of the elevator
shaft increases, the amount of moving mass (of steel elevator
cables) increases exponentially [4]. Ultrarope, however,
shows a much less dramatic, nearly linear change to mass in
relation to shaft height [4]. KONE boasts a 15% energy saving
in elevator shafts spanning 500 meters, but these savings grow
to 45% in shafts spanning 800 meters [12]. These findings
clearly indicate that carbon fiber rope shows potential to
greatly decrease energy consumption costs in future
skyscrapers, providing an increasingly sustainable platform
for lifting elevators.
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Nathanael McGuire
result in an overall decrease in the total costs surrounding
elevator use, providing a more sustainable alternative to
traditional steel. Thus, the author’s hypothesis that carbon
fiber use will decrease costs is clearly justified.
Carbon Footprint Reduction
Many agree that more cities should be constructed taller
instead of wider because this would result in a substantially
more energy efficient city, with reduced traffic and carbon
emissions [1]. Carbon fiber elevator ropes promise to aid in
the implementation of vertical city design. Although the
development does not directly cause skyscrapers to be built
taller, it gives civil engineers the opportunity to design taller
structures without being limited by the performance of
elevator cables [2]. Thus, using carbon fiber for elevator ropes
allows for a more effective construction of vertical cities
which results in a reduced carbon footprint. These construction
implications enable more sustainable cities through a greatly
reduced carbon footprint [1]. An effective example would be
the Kingdom Tower, which will be discussed in detail in the
following section.
Additionally, the increased energy efficiency resulting
from the use of carbon fiber correlates to decreasing a
building’s fuel consumption, and therefore a much greater
energy sustainability. The much lower density of Ultrarope as
compared to steel clearly indicates a potentially large
reduction in the amount of energy required to move mass
through the elevator shaft [4]. Thus, because less energy is
consumed during elevator operation, the energy needed from
power plants is also reduced. This means that less fossil fuels
and natural resources will need to be consumed for electricity
output.
Thus, based on the data, carbon fiber rope provides a
means for cities to become more energy efficient, and to
significantly decrease carbon footprint through taller
structures and less energy consumption [4]. Ultrarope offers
multiple paths for cities to take towards sustainability,
lowering energy dependencies and enabling a large cut in
emissions [4].
FIGURE 4 [4]
Comparison of moving masses between traditional steel
cable and Ultrarope as shaft height increases.
Cost Analysis
In addition to the savings which would result increased
energy efficiency, it is important that the advantages of carbon
fiber are put in perspective of its initial costs as well. Carbon
fiber is significantly more expensive than steel, so this section
will analyze the costs of each type of cable with respect to the
amount of money which could be saved long term.
While the specific figures for the cost per unit length of
Ultrarope have not been released, the initial cost gap is
estimated to be around a 20% greater expense for Ultrarope;
however, exact installation prices range substantially based on
factors such as building layout and shaft height [14]. KONE
indicated that the cost is decreasing as the scale of production
continues to increase [12]. President of KONE Matti Alahuhta
has stated that, “the price of [Ultrarope] is a bit more costly
than steel, but it works out much cheaper over the lifetime of
an elevator” [12]. Thus, although Ultrarope has a greater initial
cost than traditional steel cable, it has the potential to
compensate itself through its energy efficiency and durability.
Specifically, the 20% initial cost increase in compared with the
45% cost savings through increased energy efficiency. Using
this reasoning, it is clear that Ultrarope allows for a net cost
reduction. The speed of this payoff varies depending on
elevator shaft height, as displayed in Figure 4, as energy
savings increase exponentially over height [4].
Additionally, Ultrarope is expected to decrease the
frequency of required cable replacements, as it has an
estimated cable lifetime of 15-20 years. This is in contrast to
the 8-10 year lifetime of traditional steel cables [12]. Thus, due
simply to its increased expected lifetime, Ultrarope use would
result in a marked decrease in the frequency of replacement
costs.
Drawing information from this analysis of Ultrarope, it
is evident that utilizing carbon fiber in elevator cables would
FOCUS: ENABLING THE KINGDOM
TOWER
The commercial debut of carbon fiber elevator ropes (i.e.
Ultrarope) is scheduled to be in 2018, with the construction of
the Kingdom Tower in Jeddah, Saudi Arabia [5]. Set to be the
world’s tallest building at 1000 meters tall, the Kingdom
Tower fits perfectly into KONE’s target market for Ultrarope
[16]. The tower’s elevators are designed to break the current
records for the tallest elevator shaft, and for fastest doubledecker lifts [16]. The stronger and lighter carbon fiber cable
also allows for the elevators to reach the maximum vertical
speed that is safe for human travel, boasting speeds of 10
meters/second [5].
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Additionally, Ultrarope was a great fit for the Kingdom
Tower, as it’s developer stated, “[due to the lower density of
Ultrarope] we will be able to fit the DoubleDeck elevators with
normal machines, a huge advantage that will enhance the
sustainability of the Kingdom Tower by consuming much less
power” [5]. Designing a functional elevator system for
buildings spanning over 500 meters in height has been shown
to be nearly impossible with steel cables, but is becoming a
reality through the advancement of Ultrarope [5].
The actual implementation of carbon fiber elevator ropes
in what is planned to be the tallest building in the world clearly
demonstrates its potential. This technology allows buildings to
be constructed with continuous elevators with heights that
could not previously be attained by using steel rope. Thus, it
is clear that carbon fiber for use in elevator ropes is not only
beneficial from a material perspective, but is also a viable
alternative to traditional steel.
become the standard elevator cable for elevator shafts reaching
high heights.
SOURCES
[1] E. Glaeser. “How Skyscrapers Can Save the City.” The
Atlantic.
3.2.2011.
Accessed
1.12.2017.
http://www.theatlantic.com/magazine/archive/2011/03/howskyscrapers-can-save-the-city/308387/
[2] J. Sloan. “In super-tall buildings, carbon fiber elevator rope
rides to the rescue.” CompositesWorld. 12.1.2015. Accessed
1.11.2017.
http://www.compositesworld.com/blog/post/insuper-tall-buildings-carbon-fiber-elevator-rope-rides-to-therescue
[3] “Building Conditions Affecting Elevator Performance.”
National Elevator Industry, Inc. Accessed 1.12.2017.
http://www.neii.org/search_content_file.cfm?filename=%2Fn
eii-1%2Fpage5-26.pdf&apptype=application/pdf&vdata=y
[4] “The Next Step: KONE High-Rise Solutions.” KONE.
Accessed
1.11.2017.
http://download.kone.com/ultrarope/assets/download/KONE
_high-rise_solutions.pdf
[5] N. Ames. “Elevator installation prep begins at Kingdom
Tower.” ConstructionWeekOnline. 5.10.2010. Accessed
1.12.2017. http://www.constructionweekonline.com/article33617-elevator-installation-prep-begins-at-kingdom-tower/
[6] “Sandvik Sanicro 36Mo logging cable Precision Wire.”
Matweb. Material Property Data. 2017. Accessed 3.3.2017.
http://www.matweb.com/search/DataSheet.aspx?MatGUID=
c140b20b165941c7a948e782eeced4ea&ckck=1
[7] “DowAksa AKSACA™ A-49 24K Continuous Carbon
Fiber.” Matweb. Material Property Data. 2017. Accessed
3.3.2017.
http://www.matweb.com/search/DataSheet.aspx?MatGUID=
25a76e74d1c54a98a5946d68f20719c7&ckck=1
[8] “Patent application title: ROPE OF A LIFTING DEVICE,
AN
ELEVATOR
AND
A
METHOD
FOR
MANUFACTURING THE ROPE.” KONE. 8.15.2013.
Accessed
1.11.2017.
http://www.patentsencyclopedia.com/app/20130206516
[9] “Insulation Materials-Temperature Ranges.” Engineering
Toolbox.
Accessed
3.3.2017.
http://www.engineeringtoolbox.com/insulation-temperaturesd_922.html
[10] “Steel Rope Technical Information.” Bridon Oil and Gas.
3.2009.
Accessed
3.3.2017.
http://www.bridon.com/china/x/downloads/steel_technical.pd
f
[11] “Carbon-Fiber Elevator Rope – Innovation Description.”
Construction Innovation Forum. Accessed 1.11.2017.
http://www.cif.org/awards/2014/19_-_CarbonFiber_Elevator_Rope.pdf
[12] “Discover the revolutionary KONE Ultrarope.” KONE.
Accessed 1.11.2017. http://download.kone.com/ultrarope/
[13] M. Wembridge. “Kone reaches for the skies with carbon
cable for lifts.” Financial Times. 06.10.2013. Accessed
INCREASING THE HEIGHT OF NEW
STRUCTURES WITH CARBON FIBER
This paper has clearly shown that carbon fiber used in
elevator cables allows for increased structure height, and
decreased energy consumption, costs, and carbon footprint.
Thus, the authors conclude from the data that the hypothesis
presented at the start of this paper is justified.
The sum of the benefits of utilizing carbon fiber in
elevator cables can be most clearly seen through KONE’s
Ultrarope. Ultrarope has demonstrated a means for architects
to construct taller buildings, while keeping elevators safe,
durable, and efficient. Additionally, it has been stated that,
although Ultrarope may be more initially expensive than
traditional cable, it promises to decrease future costs and
proves to be superior to traditional steel cables over its lifetime
[12]. Ultrarope has been designed to be mechanically and
technologically superior to steel cable through its tensile
strength, durability, traction, and wear sensing [12][6]. While
commercial examples of Ultrarope are still in development,
the design specifics of the cable show that it has the
mechanical potential to be a viable option to replace current
steel cable in skyscrapers [5].
The long term economic benefit of carbon fiber elevator
ropes increases significantly with taller building heights [12].
It has the ability to connect with a niche market of skyscrapers,
enabling practical means of elevator transportation at higher
speeds and greater heights [6]. As the production of carbon
fiber rope continues to increase, the costs are expected to
decrease, thereby eliminating one of the only advantages steel
cable currently holds over carbon fiber [13]. As elevator shafts
continue to grow over 500 meters in height, carbon fiber
becomes an attractive and economically viable option for safe
and efficient elevator travel [5]. Thus, in compiling the known
data regarding carbon fiber rope, the authors conclude that,
through its mechanical, technological, and long-term
economic advantages, carbon fiber shows the potential to
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Nathanael McGuire
2.13.2017. https://www.ft.com/content/cf1f1a3e-d1c1-11e29336-00144feab7de
[14] Nick. Conversation. KONE Elevators and Escalators
Pittsburgh Branch. Accessed 2.18.2017.
[15] “Sustainable.” Merriam-Webster. 2017. Accessed
3/30/2017.
https://www.merriamwebster.com/dictionary/sustainable
[16] D. Carrington. “Real high tech: How will the elevators
work in the world’s tallest building?” CNN. 07.02.2014.
Accessed
03.01.2017.
http://www.cnn.com/2014/07/01/world/meast/kingdomtower-how-will-the-elevators-work/
ACKNOWLEDGMENTS
We would like to extend our thanks to the ENGR 0012
staff who have encouraged us in our pursuits. In addition, we
would like to thank our writing instructors, Libby Ferda and
Janet Zelleman, and to our co-chair Dan Sauder, for their
constructive input. Additionally, we would like to thank Dr.
Natasa Vidic for helping us make the paper flow together, and
understand our role in compiling relevant literature.
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Nathanael McGuire
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