Steel structure research paper

Sustainability in Efficient Steel Structure Skyscrapers Arc 406c/406c Fall 2013 Marry Ben Research Paper in Installments + Research Poster By: Ethan Taing

1.

Abstract

The steel industry is rapidly growing in skyscraper construction because of steel capability to be recycled. Skyscrapers are made possible by the invention of the elevator. The first skyscraper was in Chicago from the invention of the Chicago steel frame structure. Today buildings are so tall they must take special rigid form to encourage structural integrity due to wind and other factors of nature’s limitation. As we continue to achieve higher heights encounter exponential growth in the amount of wind forces.

Putting a limit on a skyscraper height should not be done but understood. After the 50th floor the building becomes unsustainable even though people are willing to pay for a beautiful view and a iconic building its not right to be such large consumers in a unsustainable way. Tall buildings also require higher construction cost wind bracing, decreasing floor area, building components and elevators take up more room. As we become environmentally conscious, yet still bond by economic efficiency we are now creating buildings with diagrid, which is a more efficient steel structure. The structure of a skyscraper is similar to the I beam, buildings structure should be sized properly to ensure its materials capability. It’s important to understand that our skyscrapers structures are ever changing. In order to understand the development of structure this research compares factors influencing the structural sustainability of 7 well known steel incorporated structure skyscrapers dating from 1930s-Today. In order to determine how sustainable a structure is it will be calculated by the lbs of material needed to support each sq’ of usable space. As technology and construction methods continue to change the heights of a sustainable skyscraper is ever-increasing.

2.

A forever-changing world

The ideals of a skyscraper and definitions are changing dramatically as the demand increases for skyscrapers. The structure of a skyscraper is the highest expense of a project (typically 15-20% of budget). “Steel is a large embodied energy consumer due to the high heat needed to form steel into shapes we can build with”.(FSH) The Home Insurance Building in Chicago built in 1884, was the first skyscraper back in its time, but today its height is not considered a skyscraper.

“Steel as a material is 100% recyclable, and still retains a high capacity under compression and tension even after being recycled as long as its ratio of iron, carbon, sulfur, manganese, and nickel remains A992 Steel. “ (FSH)

Behind the scene work of a skyscraper

The foundation of a building is not only about the cost of materials but the amount of excavation needed to produce a mold for concrete and steel reinforcement. The comparison of Chicago and New York is a good example of two different soil compositions impacting the budget. Fig.1 shows the difference in depth in order to hit bedrock. All skyscrapers require a solid foundation, and the only way to root itself into a stable foundation is to drill piles below the bedrock line. As shown in Fig. 1 it requires much more excavation and more material to produce its structural system. We will be looking at the amount of steel used in order to produce a skyscraper so we must take into consideration that sites also impact that amount of Steel used in a building.

Clients may have a range of ecological awareness because they are primarily focusing on their needs. The clients are the ones who make the final decision, so it’s the job of the architect to help them understand what we do to make judgment calls. Architects are known for their logical reasoning behind a decision. Clients are typically concerned about the budget, profits and aesthetics so its our job to help them understand the parts that make a skyscraper such as structural systems.

The competition is high due to the economy and if someone won’t build the skyscraper they want, they will go to the next architect.

Typically in a dense area it makes a lot of sense to build a tall building because you are able to charge a lot due to limited space and demand. There is also an idea of iconic tall buildings that break the world record due to economic reasons.

Sometimes we need people to be cutting edge with technology but at the same time be aware of our environmental impacts because it’s the architect’s job to do no harm to humanity. The people deciding the heights of skyscrapers today are ignoring the amount of steel need to construct these buildings they imagine and dream of, due to the demand of breaking world records and the availability of our natural resources.

The site is uncontrollable in most cases because skyscrapers will only work in high density and high land value areas. The site can impact a skyscraper economic and sustainable heights of the skyscraper. Sites at various locations have different soil composition and ecological challenges. Old dense cities never took into consideration of sustainable sites to buildings on. They were more concerned about the views and location.

For example the three largest cities in the US, New York, Los Angeles, and Chicago all are located by water because they are old cities that depended on hydroelectricity to keep a city functioning. There are many more reasons such a transportations and air quality but the list doesn’t stop.

Figure 1

3.

Locations such as Taipei have seismic zones must be resistance to shear loads when earthquakes occur. Chicago and New York must build considering wind loads from Tornados and Hurricanes. In order to design for a building to survive high ground movements and wind loads, engineers must over load our structure. By doing so more steel is used then actually needed for its daily wind loads. Designing for the maximum load of a skyscraper that occurs within that 1% out of every 100 years requires a substantially heavier structure.

As the appetite for skyscrapers is in high demand, skyscraper structure advanced as engineers learn from experience. Regardless of what type of structural frame you have it will be located on the inside or outside of the building. Typical in steel buildings it’s better to keep steel on the inside to prevent rust. Starting at the simplest and lightest weight capacity frame is a tube structure by just having an exterior structure. “The Framed tube-in-tube was developed because of the the need for a fire exit which is in the center core and could be easily being doubled down as a structural system. As buildings became taller shear was the highest concern so architects designed a trussed tube-in-tube system for example the John Hancock tower in Chicago. Then after the need to create taller buildings the framed tube and hat/belt trusses helped double down as structural systems by buttresses with diagonal shear bars that don’t disturb the windows.” (Kyoung) Today we use similar structural systems and manipulated them to a more efficient structures like the diagrid.

The diagrid is essentially a trussed tube-in-tube at a micro level. The more points to help diverge forces into the ground the less weight and more efficient structure.

Another way of designing a more efficient structures today is to calculate a lighter structure by sizing accordingly and not over building structures. There is only two ways of advancing steel structures today and it’s either the way we use it or the material itself.

The form of the building will effect a structures efficiency. Wind is strong at higher elevations so the more laminar air and less disturbance in wind direction the lower the coefficients is. (Fig. 2) To understand the type of forces a skyscraper will face, the angle the wind is directed by the building can dramatically increase the capacity of the building. The higher you’re building the more these coefficients will impact the weight capacity due to higher wind speeds.

Figure 2

Skyscrapers in the 1930s

Back in the 1930s a 40-story building would not be sustainable due weaker material and construction methods.

Most of them actually used a large amount of steel to be cladded with heavy masonry, compared to our glass facades today. Elevators were less efficient and needed more space. “The steel capacity per cubic inch back in the 1930s was also 10ksi lower then the capacity we have today meaning more steel was used in order to hold its capacity requirements.” (W.Bates) The taller the building the more expensive the foundation will cost. Fig. 3 shows how foundations increases dramatically once climbing over 22 stories. Structural Steel is increased and no longer sustainable after 37 stories. Elevators are also similar to structural steel in how they tend to need more per sq.’ as buildings grow taller. The profits per sq. feet will also increase as they go higher due to views of the city skyline, as long as there is a demand in the market. Concrete floors will get cheaper cause of less floor area as the building becomes taller, and so with exterior, interior materials, and mechanical equipment. In Fig.4 The total floor area back in the 30’s are substantially smaller after 15 stories.

The demand for prime real estate at these heights were high so the economic side of things out weighed the most logical sustainable height back then. “The most efficient height back then would be around 8-20 stories thinking of the amount of steel needed per sq. feet.” (Clark) In order to build the most efficient building the building must be produced keep in mind the amount of material per sq. foot. The tables don’t get us the amount of materials but the proportions of dollars to materials was accurate cause the profits were not in the calculation.

4.

The tallest building in the 1930s was the Chrysler building, which is still the tallest brick building in the world.

It is albeit with an internal steel skeleton. The 1,195,000 sq. Ft. building that reaches 1,046 feet and, contains 21,000 tons of steel. The buildings use about 17.57 lbs of steel per sq. ft. The building is located in New York City and has a efficient form structurally by tapering, each time levels tier off they become a buttress for the building.

During the construction of these buildings a series of economic studies were done in order to understand the economics of a skyscraper due to their limitations of nature. The building understands that the higher you go the less gross floor area usable because of elevators, mechanical and floor area. Fig. 4 shows you a table of an average floor area being deducted as skyscrapers becomes taller.

Figure 3

As buildings become taller more material and labour is needed can be summed up by the Total Direct Labor and Material Cost column. The calculation is not including inflation since the 1930s.

Figure 4

At the 75th story the buildings gross floor area is reduced dramatically due to the limitations of the construction method and material available in the 1930s.

5.

The Carew Tower in Cincinnati, OH was considered a mid range building in the 1930s. The 1,377,780 sq. Ft. building that reaches 547 feet and contains 15,000 tons of steel. The building is cladded with a brick exterior with a steel structure, and uses about 10.89 lbs of steel per sq. ft. The building is located in Cincinnati which bedrock depth is similar to Chicago. The foundation had to touch bedrock to prevent the building from sinking into the soil. Reaching 547 feet this building wind loads is not a main concern because of its capability to resist wind from its wide base acting as a buttress. Its form is also tiered so it’s able to reach its maximum efficient form.

Comparing the two buildings will determine the economical height with the building construction knowledge we had back then it would have been. Cincinnati land value is much cheaper then New York’s, so they were able to build about the same amount of sq. ft. spread throughout 54,960 sq. Ft. on the ground level, where as the Chrysler building uses 31,266 sq. Ft. on the ground level. The Economics of a skyscraper is typically a higher priority then sustainability of efficient structures. The client’s primary concern is the amount of square footage needed in a building specified. The embodied energy in a material hinders the cost, but as of today we are able to construct both the buildings with a fraction of the steel used due to better design and strengths of steel.

Chrysler Building New York City 17.57 lbs of steel per sq ft.

Carew Tower in Cincinnati, OH 10.89 lbs of steel per sq ft.

Figure 5 Carew tower understands the economic height every well and split its required sq footage into one mid night skyscraper and a low one.

The Chrysler building marks the end of heavy facades and understand how much bulkier a structure can be by being cladded in brick.

6.

Skyscrapers in the 1970s

During the 1970s the American Institute of Steel created a new book using the Enhanced capacity A992 steel the guide facilitated structural design without guess work . With the new guide it also made calculations more efficient because buildings were allowed lower capacity from experience of over built structures. The new capacity for this steel was 60ksi compared to the old 50ksi steel before the 1970s. There were much more specifications and new technology to help us design. Engineers are able to design parametrically for complicated structures, which helped lower the design time and errors. “The first programmable computer called the Colossus designed in 1943

by Tommy Flowers to help link the computer to be used in all fields including architecture & engineering. Not until 1970 when the Intel 4004 microprocessor was invented was it affordable for large companies. New and innovative designs such as the diagrid were invented during this time.” (Nano) The united steelworks building in Pittsburgh is a low rise building that uses 3 different strengths of steel and, a space frame diagrid structure for its façade. This made it an extremely efficient structure but, was expensive due to custom fabrication and labor, making it only available to small-scale buildings. The reason architects are able fabricate structural parts precisely is because of the digital modeling world. A digital model is very helpful in estimating the amount of materials needed and size of parts because, it simulates an real world way of constructing the building.

The Willis tower was innovative in using the framed tube and hat/belt trusses and bundled them together to create larger buttresses. The large buttresses help create an efficient steel structure within the form of the building itself against wind. The 4,560,000 sq. Ft. building reaches 1,450 feet and contains 76,000 tons of steel. The building is cladded with a glass curtain wall system which, is much lighter then a brick facades in the 1930s. The building uses about 16.67 lbs. of steel per sq. ft. including over sizing the structure due to possible wind loads. Being built in Chicago the site needed a deep foundation systems with large amount of steels to insure safety to its occupants.

The Twin Tower NYC WTC was a framed tube-in-tube building. It was sustainable because it split its needed square footage into 7 buildings with two towers reaching for the skies. The Twin towers did not want to occupy all the available land to allow for an outdoor area for occupants. Tower one itself was 4,759,040 sq. Ft. building that reached 1,368 feet and contained 100,000 tons of steel. Tower one was cladded with glass in between its exterior structure and uses about 21.02 lbs. of steel per sq. ft. Being built in New York, it had a site advantage because bed rock was easy and deep excavation was not needed. The site itself is sustainable and the idea of splitting the amount of sq. ft. needed into 7 buildings at different heights but the two tallest were twins. If 7 buildings were built into one absorbing the same amount of land much more steel would have been used to be able because the building would of needed to be taller which means higher wind velocities.

Comparing the Willis tower to the Twin towers is evident that the Willis tower is much more efficient, with the amount of steel used per sq. ft.. The Willis tower save about 4.35 lbs. of steel per sq. ft. In the 70s steel cost $60 per ton which the two towers at 9,512,080 sq. ft. would save 41,377.5 tons of steel and $2,482,652.88 which is $37,500,000 in 2012. The reason why the solid rectangle form was chosen was to maximum amount of sq. ft., due to such high land value and demand in the center of the economic hub of Manhattan. At the same time it can be argued that the twin towers could of used more of their site to allow a wider base for wind resistance. The Willis tower was able to expand on a 50,176 sq.’ ground level compared to Tower one had a limited 40,000 sq.’ on the ground level. Being able to have a wider base on skyscrapers allow them to use less steel in order to stabilize its foundations and also means shallower foundations needed.

The World Trade Center was probably value engineered, we can presume the developers figured that the 2.4 million dollars was worth sacrificing to allowing more sq.’ for the higher levels. The Willis towers top-level only has 11,175 sq.’ while in the twin towers they had 40,000 sq.’. Both towers are site specific and innovative, the Willis tower has a sustainable efficient steel structures. The twin tower uses its knowledge of a typical tier building and shattered the stereotypes of a skyscrapers allowing it to have the same out of sq.’ on the ground floor as the top floor. The reason for both the buildings have different intentions is because of its site and economic reasons.

7.

As Skyscrapers become taller, load capacites become more of an issue. At 100 stories 65lbs. per sq. ft. was deducted from its floor plate weight capacity meaning it will cost substantially more than its average for higher floors. The twin towers has 40,000 sq. ft. at its 100th level losing 2600 tons of capacity to react to the wind loads.

Compared to the Willis tower has 11,175 sq. ft. at its 100th level losing 726.37 tons of capacity to react to wind loads. The Willis tower has a more efficient steel structure because its bundle tube form allows more rigidity in the structure. The data was taken from fig. 2 as you can see the coefficient of amount of capacity loss is changed at different levels due to different wind velocities.

An efficient structure doesn’t always mean an efficient skin. The Willis tower and the Twin towers are similar in weather in the fact that heating is its dominating energy user while in operation. The Willis tower is painted black to help its heat gain because the coefficient of the absorption of black is much higher then white. While the color is helping the Willis tower regain loss heat it has much more surface area of its skin exposed to the weather.

The twin tower has a great thermal envelop because there is no extra roof to account for and surface area meaning the operational cost of heating and cooling is much less then the Willis tower. There are always trade-offs and to estimate a whole building life cycle is a very complex and continual study that is outside the scope of this paper.

Willis Tower Chicago, IL 16.67 lbs. of steel per sq. ft.

Tower One NYC 21.02 lbs. of steel per sq. ft.

Figure 6 The Twin Towers used a framed tube steel frame because it allows an infinite amount of interior configurations. by actually having fewer point loads the structure is larger taking up more floor area then the sears tower.

The Sears Tower is the icon of Chicago and will always be due its history of the innovative Bundle Tube steel frame making skyscrapers extremely efficient due to the amount of buttresses possible within the grid. Even till today we build skyscrapers with similar form concepts for efficiency.

8.

Skyscrapers from 2000-Today

Skyscrapers are in a high demand then ever due to the over populating world, and the need to condense our footprint to allow for enough land to keep us alive. As technology continues to grow the development of structures will continue to grow exponentially. We now have learned more then ever about the properties of concrete.

Before concrete was not standardize because we never imagined to work in tall skyscrapers. We are now able to keep concrete at a consistent mixture to ensure a specific capacity of design. Concrete as a material is much cheaper then steel and, is the reason why we have and are able to develop so many more structures then we can.

Steel Structures are still the only 100% recyclable resource for structures. Structures that are concrete is not as easily recyclable but the steel reinforcement is. It is not a big deal because in order to disassemble a steel skyscraper it would cost just as much, if not more to put it up. We now understand how the hybrid of steel and concrete helps creates a more efficient structure. Concrete acts as a fire retardant but at the same time works in compression. Steel works well in tension countering wind loads and natural disaster. The down fall with concrete is that when the building fails it fails instantly compared to steel, due to its ductility and tension capabilities its able to retrieve extra strength even though it has failed it would not collapse. Steel Structure is much safer then Concrete reinforce buildings before but now that we understand the properties of concrete we are able to insure the safety of its occupants.

Building and computing technology plays a big roll in the future of architecture. Engineers are now able to analyzing the wind loads and specifics better then ever. In every firm today employees are provided to everyone.

With a powerful computer capable of designing a full out skyscraper architects and engineers are able to incorporate and integrate our knowledge without having to extensive education in each field. The forms of skyscrapers also became more complex and less rectilinear because the capability of designing buildings parametrically reducing hand based calculations of the structure. By creating non-rectilinear buildings we are able to receive wind at a low angle allowing for less impact of wind loads of the building.

Currently the tallest building in the world is the Dubai Burj Khalifa. “The 5,000,000 sq. Ft. building reaches 2,722 feet and requires 431,600 cu. Yd. of concrete and 43,000 tones of steel.” (The Tower) The Burj Khalifa is able to reduce its consumption of steel to 8.6 lbs. Per sq. ft., due to the use of 1.55 cu. ft. per sq. ft. of concrete. The concrete cost about $11.97 per cu. sq. ft. and the steel cost about $4.82 per sq. ft.

The Burj Khalifa has a innovative knife edge corners at 5 degrees to help cut wind loads down by 5.77 x, meaning at the 100th it will receive 11.27 lbs. Per sq. ft. That means at 12,351.5 sq.’ it saves 663.645 tons of capacity in the concrete reinforced steel structure, allowing a much more efficient form compared to a rectilinear shape building. The 3 wings act as buttresses and so does the tearing affect. This building looks at a much more macro level in the form of the design to encourage structural integrity. There was no site limitation allowing for a expansive amount of land to be used in Dubai. Ironically this building was designed by SOM located in Chicago who is knowledgeable of skyscrapers due to home base advantage Chicago, where the invention of the skyscraper took place.

A similar building to the Burj Khalifa would be the Trump International Tower in Chicago. The 2,600,000 sq.’ building reaches 1,170 feet and required 180,000 cu. yd. of concrete. The building uses 2,630 tones of steel. The Trump Tower uses 1.01 lbs. Of steel per sq.’ and 1.24 cu. ft. per sq. ft. of concrete. Some of the complex structural problems of this project was that it is cantilevered into a section of a 420 million year old lime stone bed rock.

The foundation reached about 110’ underground and requiring the structure to be over sized. The Trump tower uses a round diamond shape allowing for the wind loads be taken at 20 degrees, cutting down ½ the amount of steel needed saving the building about 383.500 tons of capacity in the concrete reinforced steel structure on the 96th floor.

9.

The most current all steel skyscraper today is Taipei 101. The 2,081,700 sq.’ building reaches 1,671.3 feet required 106,000 tons of steel. Taipei 101 uses 50.92 lbs. of steel per sq. ft.. The building uses an expansive amount of steel then any precedent talked about in this paper due to the fact that the form doesn’t taper, which means no buttresses created within the form and making it susceptible to typhoons with very high wind loads. Due to its square shape and 90 degrees angle its 38,021 sq.’ 100th level floor plate required 2,471.37 more tons of capacity in order to reduce wind loads. In order to lower this number there is a dampening system, which is a steel ball in the center of the building that will tilt a specific direction in order to reduce its capacity need to fight against wind loads. Even with this steel ball damper the structure still need to be overloaded for safety. Due to the amount of technology today we are able to build buildings like the twin tower in places we would never imagine. Taipei 101 proposes a challenging question to ask about what is the sustainable height for the site given limitations.

After reviewing the 3 projects of 2000-Today there is a big difference from the 1970s, as forms get more complex because we have the technology capable of computing complex forms, they can be used to help make a skyscraper more efficient. All 3 buildings show an innovative mark in how they approached technology into helping them become efficient with its limitations of the site. The Burj khalifa focused on cutting wind loads by 570% with its knife-edge form allowing for a wind dynamic form that reduces the size of the structure. The Trump Tower’s deep foundation proposed a inefficiency factor but bounced back by the efficient of the tier effect and form. The Trump Tower’s bed rock at 110’ compared to the Twin Tower bed rock at 10’ will increase the cost and materials. Taipei 101 was able to use technology and incorporated into their buildings such as the wind damper to make a steel structure in a seismic and typhoon zone more sustainably efficient. With out technology a skyscraper as large as Taipei 101 would of been even more so unsustainable.

Dubai Burj Khalifa 8.6 lbs. Steel per sq. ft. & 1.55 cu ft. concrete per sq. ft.

Taipei 101 Taiwan 50.92 lbs. of steel per sq. ft.

Trump Tower Chicago ,IL 1.01 lbs. steel per sq.’ & 1.24 cu ft. concrete per sq. ft.

10.

Chicago

Taipei

Dubai

On the 163rd Floor Burj Khalifa 7564 Sq. Ft.

On the 101th Floor

Trump Tower 11,210 Sq. Ft.

Taipei 101 5548 Sq. Ft.

12995 Sq. Ft.

34,408 Sq. Ft.

56,307 Sq. Ft.

Figure 7 The 3 most recent buildings of today are quite different in site, culture and design concept. In the structure of the three are all bundled tube frame. Taipei 101 with steel and Trump/Burj with concrete steel reinforce material. Dubai was the most conscious of wind and should be due to its height but the other two did not consider wind as a big factor. There could be many reasons but here is one. Taipei 101 had the same issue as the Twin Towers and wanted to maximize floor sq footage. Trump Tower wanted to also use its build on its entire site due to land value similar to New York and with its setback requirements also maximized its sq footage but at the same time was cut short due to its need of a deep foundation.

On the 98th Floor

11.

The Future of Skyscrapers

As we continue to learn from our mistakes skyscrapers will become more efficient and, understand the positive and negative impacts. It is proven that there are positive ecological reasons behind a mid height building (about 50 stories). Fig.8 shows a 40 story high building with the most updated standard building methods and materials. The 40 story building is much more efficient in the amount of land and materials it uses to build something similar in a suburban sprawl environment.

While looking at this issue it doesn’t take into consideration of human impacts and the idea of biophilia the need to be connected to nature. Having a lifestyle and being in a building all day can really impact the human aspect of architecture the health and happiness. Matter how much we try to put gyms and green plants in a building it wont replicate being outdoors. As the worlds population exponentially grows it might be a possibility that we have to live in skyscrapers and high density urban areas.

Steel should be used as efficiently as our knowledge will allow us. Site, form, technology, and material should all be taken into consideration and that its not acceptable to build because that what we in vision. As clients have a point of view architects must pitch to them that sustainable efficiency of the structure will also impact economically that require a type of aesthetic in its form. We know so much more about the material today then yesterday.

Skyscrapers are already as tall as they should be due to its limitations of wind forces. The higher we go the more we need to develop materials and construction methods to feed our appetite for being the highest skyscraper in the world. Its morally incorrect to consume materials because we can understand that the ideal building is really a mid height building not taller then 50 floors. The 50 floors take into consideration of land usage, materials, operational/maintenance cost and the construction.

We are able to get stronger steel today and we are able to use it more efficiently because of all these growing computers and more complex ways of sizing steel members. For instance the American Institute of Steel has doubled in its book size to help people make the better choice of sizing steel. Currently the diagrid is the cutting edge.

Innovative structures are prototypes and hard to standardize due to its little life experience invested into the prototype. We will soon see a development of the tensegrity steel structure and the hybrid of concrete and steel after the diagrid has been standardize. In order to build a skyscrapers structure it must be standardize and proven to due to the amount of energy and materials it consumes.

Looking from an ecologist standpoint its good to have that much soil depth like Chicago even thought it means deeper and larger foundation systems because it will mean less water run off and capable of growth of mature tall trees. Skyscrapers propose a complex problem that must be analyzed for a long period of time due to its scale.

The paper only analysis the standpoint of an efficient structure and ignores the other multi variables into creating a skyscraper. The only way for architects to multi task and dip into many different categories of sustainability in a skyscraper is computers. Technology is key to our survival until the end. As Fig. 9 shows our growth of nano technology. Nano technology focuses 34% in Hybrid Materials 20% in Information Technology which is the two main factor into sustainable skyscrapers.

An ideal Efficient Skyscraper today would be one that uses a hybrid material that understands the need to resist tension, compression and shear loads. Today the most efficient material would be a concrete reinforced building.

Methods of making steel has also improved allowing for less energy to be used but, the cost of material goes up because steel is a non replenishable. Technology will be inevitable as they become more realistic to understand its condition when built at a certain location. Taipei 101 have showed how technology can be incorporated to help the efficiency of the structure of a building. Now that we understand sites better there is a sustainable height and the cities with bed rock at shallow depth will allow the most sustainable buildings. In the end wellness and happiness is the limits of how high we can go. Humans are a part of nature and should not be separated into a box somewhere high up in the skies limiting human interactions. We will continue to learn from our mistakes until the end of civilization and today ideals wont be tomorrows.

12.

Figure 8

Figure 9

13.

“You must make a decision that you are going to move on. It wont happen automatically.”

- Joel Osteen “Tonight, we gather to affirm the greatness of our nation not because of the height of our skyscrapers, or the power of our military, or the size of our economy. Our pride is based on a very simple premise, summed up in a declaration made over two hundred years ago.”

-Barack Obama

Tower One NYC 21.02 lbs. of steel per sq. ft.

Trump Tower Chicago ,IL 1.01 lbs. steel per sq.’ & 1.24 cu ft. concrete per sq. ft.

Chrysler Building New York City 17.57 lbs of steel per sq ft.

Carew Tower in Cincinnati, OH 10.89 lbs of steel per sq ft.

Figure 10

14.

We must limit to ourselves to what we consume to fulfill our dreams. Skyscrapers are no longer a game of who can have the tallest but, who can be the most sustainable reaching highest of a skyscraper.

Willis Tower Chicago, IL 16.67 lbs. of steel per sq. ft.

Taipei 101 Taiwan 50.92 lbs. of steel per sq. ft.

Dubai Burj Khalifa 8.6 lbs. Steel per sq. ft. & 1.55 cu ft. concrete per sq. ft.

15.

Appendix/Calculations Building

Carew Tower Cincinnati, OH

Chrysler Building New York City

Trump Tower Chicago ,IL

Tower One New York City

Willis Tower (Sears Tower) Chicago, IL

Taipei 101 Taiwan

Data from various sources Height: 547 feet Size: 1,377,780 Sq. Ft. Structure: 15,000 tons of steel Source: ”Carew Tower Remains One of City’s Signature Buildings.” Visitor’s Guide: Cincinnati.Com. N.p., n.d. Web. <http://www.cincinnati.com/visitorsguide/stories/022701_ carewtower.html>.

Height: 1,046 feet Size: 1,195,000 Sq. Ft. Structure: 21,000 tons of steel Source: Chrysler Building - Piercing the Sky.” Cbsforum.

N.p., n.d. Web. <http://www.cbsforum.com/cgi-bin/articles/ partners/cbs/search.cgi?template=display>.

Height: 1,170 feet Size: 2,600,000 Sq. Ft. Structure: 180,000 cu yd. of concrete 2,630 tones of steel.

Source: Trump Tower.” Case Foundation. N.p., n.d. Web. <http://www.casefoundation.com/projects/Trump_Tower. aspx>.

Height: 1,368 feet Size: 4,759,040 sq ft Structure: 100,000 tons of steel.

Source: Johnson, David, and Shmuel Ross. “World Trade Center History.” Infoplease. Infoplease, n.d. Web. <http:// www.infoplease.com/spot/wtc1.html>.

Height: 1,450 feet Size: 4,560,000 sq ft Structure: 76,000 tons of steel Source: Comprehensive - Fact Sheet about Willis Tower | Willis Tower.” Comprehensive Fact Sheet about Willis Tower | Willis Tower. N.p., n.d. Web. <http://www.willistower.com/ building-information/history and-facts>.

Height: 1,671.3 feet Size: 2,081,700 Sq. Ft. Structure: 106,000 tons of steel.

Source: Taipei 101 - A Case-study.” Archinomy. N.p., n.d.

Web. <http://www.archinomy.com/case-studies/671/taipei101-a-case-study>.

Per Sq. Ft.

(15,000 tons x 1000 lbs/ton)/ 1,377,780 Sq. Ft. =10.89 lbs of steel Per Sq. Ft.

(21,000 tons x 1000 lbs/ton)/ 1,195,000 Sq. Ft. = 17.57 lbs of steel per sq ft.

(2,630 tons x 1000 lbs/ton)/ 2,600,000 Sq. Ft. 1.01 lbs of steel Per Sq. Ft. (180,000 cu. yd. x 1/18 Ft./yd)/ 2,600,000 Sq. Ft. = 1.24 cu. Ft. of concrete per Sq. Ft.

(100,000 tons x 1000 lbs/ton)/ 4,759,040 Sq. Ft. =21.02 lbs of steel per Sq. Ft.

(76,000 tons x 1000 lbs/ton)/ 4,560,000 Sq. Ft. =16.67 lbs of steel per Sq. Ft.

(106,000 tons x 1000 lbs/ton)/ 2,081,700 Sq. Ft. = 50.92 lbs of steel per Sq. Ft.

16.

Appendix/Calculations Cont.

Data from various sources

Building

Burj Khalifa Dubai, United Arab Emirates

Height: 2,722 feet Size: 5,000,000 Sq. Ft. Structure 43,000 tones of steel

431,600 cu. yd. of concrete Source: The Tower | Facts & Figures.” The Tower | Facts & Figures. N.p., n.d. Web.

Per Sq. Ft. (43,000 tons x 1000 lbs/ton)/ 5,000,000 Sq. Ft. 8.6 lbs of steel Per Sq. Ft. (431,000 cu. yd. x 1/18 Ft./yd)/ 5,000,000 Sq. Ft. = 1.55 cu. Ft. of concrete per Sq. Ft.

Work Cited

Ascher, Kate, and Rob Vroman. The Heights: Anatomy of a Skyscraper. New York: Penguin, 2011. Print.

(Ascher) (Figure:1&8) Broto, Eduard. High Density: Environments for the Future. Barcelona, Spain: Carles Broto I Comerma/Links, 2010.

Print. (Broto) Clark, W.C. The Skyscraper: A Study in the Economic Height of Modern Office Buildings. N.p.: n.p., n.d. Print. (Clark) (Figure: 3-4) “Fact Sheet Energy.” Worldsteel Association. N.p., n.d. Web. <http://www.worldsteel.org/dms/internetDocumentList/ fact-sheets/Fact-sheet_Energy/document/Fact%20sheet_Energy.pdf>. (FSH) Kyoung Sun, Moon. “19.” Structural Developments in Tall Buildings: Current Trends and Future Prospects. By Ali Mir M. Vol. 50. N.p.: n.p., n.d. 205-23. Print. (Kyoung) ”NanoTechnology and the Fight Against Terrorism.” - Directions Magazine. N.p., n.d. Web. <http://www.directionsmag. com/articles/nanotechnology-and-the-fight-against-terrorism/123894>. (Nano) (Figure:9) W. Bates CEng FIStructE. Historical Structural Steelwork Handbook. N.p.: British Constructional Steelwork Association, n.d. Steel Construction. Web. (W.Bates) (Figure:2)

Sources of Figures

Created by Ethan Taing: Figure 5,6,7,10,11 From Clark W.C: Figure 3,4 From Ascher Kate: Figure 1,8 From W Bates: Figure 2 From Nanotechnology: Figure 9