Upon completion in 2014, it stood at 1,005 feet tall, making it the tallest residential building in the city for a few months until the completion of 432 Park Avenue. The building has 92 condominium units on top of a new Park Hyatt Hotel with 210 rooms, Extell Development Company’s founder and President, Gary Barnett, spent 15 years assembling the property and air rights on 57th Street. At first, he said he wanted to build a 300,000 square-foot building, foundation work started in January 2010. In May 2012, it was announced a buyer had agreed to pay a price in New York of more than $90 million for the 10. Just two months later, the Prime Minister of Qatar, Sheikh Hamad bin Jassim bin Jaber Al Thani, after the sales offices had been open for six months, Extell announced One57 was 50% sold with $1 billion in transactions. On June 20,2012, it was announced that framework for the top floor had been completed, shortly after, it was revealed the 13, 550-square-foot “Winter Garden” duplex penthouse, located on the 75th and 76th floors, had gone into contract for an undisclosed amount.
In October 2012, entrepreneur Michael Hirtenstein and One57 developer Gary Barnett had a public clash regarding a unit Hirtenstein agreed to purchase in the building. Hirtenstein claimed he would not spend $16 million for a unit without seeing it, by November 5, the crane was secured and through traffic in the surrounding area was allowed. The New York City Department of Buildings stated they had received complaints about the work site. However, the crane was inspected a week earlier and considered in good shape, City officials called the failure of the boom a freakish occurrence. In May 2013, Extell announced plans to hoist a new crane on May 10–11, the plans endorsed by the New York City Buildings Department involved a mandatory evacuation of the neighboring Alwyn Court as well as the Briarcliff Apartment Building during the process. The residents of the building would receive up to $1,500. The coop board at Alwyn Court announced that it would seek an order against the forced evacuation. The crane was hoisted on May 11 as planned after Extell and its tasks completed, the replacement crane was removed on November 11,2013.
Neither Extell nor Lend Lease has ever offered any explanation of the fire, the cause of the fire remains a mystery. The tower was designed by Pritzker Prize-winning French architect Christian de Portzamparc, the interiors are by New York-based designer Thomas Juul-Hansen. The use of dark and light glass on the building’s exterior creates vertical stripes, while manipulating sunlight, the tower is characterized by its rippled canopies and numerous setbacks on 57th Street, its mottled fenestration, curved tops and accentuated verticality. One57 is currently the tallest mid-block building in New York City, having succeeded 40 Wall Street, One57 was named Worst Building of the Year in 2014 by Curbed. com, whose review said, Pretty much everyone agrees that its wavy blue facade is ugly
Keangnam Hanoi Landmark Tower
Keangnam Hanoi Landmark Tower is a supertall skyscraper in Pham Hung Boulevard, Từ Liêm District, Vietnam. The complex consists of one 72-story office tower with the height of 350 m and two 48-storey residence towers. Landmark 72 is located on an area of 46,054 m2, the investor as well as the executor and operator of this complex is the South Korea-based company named Keangnam Enterprises, Ltd. The investment capital for this complex is estimated $1.05 billion USD, on November 2010, the main tower reached approximately 300 metres, making it the tallest structure in Vietnam. On 24 January 2011, the tower topped out at 350 metres. The complex features a 5-star InterContinental hotel, entertainment areas, retail spaces, the complex opened for business on 18 May 2012. Landmark 72 is the world’s 35th-highest building and the highest in Indochina Peninsula, Keangnam Enterprises indirectly owned a 70-percent stake in Landmark 72. The company invested over US$1 billion with US$510 million borrowed from banks, Landmark 72 is the site of Vietnam’s highest stair climbing race, the Vietnam Landmark 72 Hanoi Vertical Run.
On 30 September 2012, runners competed for the first time to be the fastest to ascend the towers 1,914 steps, in 2013, Keangnam was facing a liquidity crisis and intended to refinance or sale of the complex. When the deal fell through, Keangnam entered into court receivership in South Korea. List of tallest buildings in the world List of tallest residential buildings in the world List of tallest hotels in the world InterContinental Hanoi Landmark 72 http, //www. landmark72. com
Bank of China Tower (Hong Kong)
The Bank of China Tower is one of the most recognisable skyscrapers in Central, Hong Kong. It houses the headquarters for the Bank of China Limited, the building is located at 1 Garden Road, in Central and Western District on Hong Kong Island. Designed by I. M. Pei and L. C Pei of I. M Pei and Partners and it was the tallest building in Hong Kong and Asia from 1989 to 1992, and it was the first building outside the United States to break the 305 m mark. It is now the fourth tallest skyscraper in Hong Kong, after International Commerce Centre, Two International Finance Centre, the 6,700 m2 site on which the building is constructed was formerly the location of Murray House. Once developed, gross floor area was expected to be 100,000 m², the original project was intended for completion on the auspicious date of 8 August 1988. However, owing to delays, groundbreaking took place in March 1985. It was topped out in 1989, and occupied on 15 June 1990, the building was initially built by the Hong Kong Branch of the Bank of China, its Garden Road entrance continues to display the name Bank of China, rather than BOCHK.
The top four and the bottom 19 stories are used by the Bank, ownership has since been transferred to BOCHK, although the Bank of China has leased back several floors for use by its own operations in Hong Kong. The Government had apparently given preferential treatment to Chinese companies, and was criticised for the apparent preferential treatment to the BOCHK. The price paid was half the amount of the 6,250 m² Admiralty II plot, the BOC would make initial payment of $60 million, with the rest payable over 13 years at 6% interest. The announcement of the sale was handled, and a dive in business confidence ensued. The Hang Seng Index fell 80 points, and the HK$ lost 1. 5% of its value the next day, designed by Pritzker Prize-winning architect I. M. Pei, the building is 315.0 m high with two masts reaching 367.4 m high. The 72-story building is located near Central MTR station and this was the tallest building in Hong Kong and Asia from 1990 to 1992, the first building outside the United States to break the 305 m mark, and the first composite space frame high-rise building.
That means it was the tallest outside the United States from its year,1990. It is now the fourth tallest skyscraper in Hong Kong, after International Commerce Centre, Two International Finance Centre, a small observation deck on the 43rd floor of the building is open to the public. The structural expressionism adopted in the design of this building resembles growing bamboo shoots, symbolising livelihood, the whole structure is supported by the four steel columns at the corners of the building, with the triangular frameworks transferring the weight of the structure onto these four columns. It is covered with curtain walls. In Star Trek, the building is used as the exterior of Starfleet Communications Research Center, the building in seen on the attraction Its a Small World at Hong Kong Disneyland
A skyscraper is a tall, continuously habitable building having multiple floors. When the term was used in the 1880s it described a building of 10 to 20 floors. Mostly designed for office and residential uses, a skyscraper can be called a high-rise, for buildings above a height of 300 m, the term supertall can be used, while skyscrapers reaching beyond 600 m are classified as megatall. One common feature of skyscrapers is having a steel framework that supports curtain walls and these curtain walls either bear on the framework below or are suspended from the framework above, rather than resting on load-bearing walls of conventional construction. Some early skyscrapers have a frame that enables the construction of load-bearing walls taller than of those made of reinforced concrete. Modern skyscrapers walls are not load-bearing, and most skyscrapers are characterized by surface areas of windows made possible by steel frames. However, skyscrapers can have curtain walls that mimic conventional walls with a surface area of windows.
Modern skyscrapers often have a structure, and are designed to act like a hollow cylinder to resist wind, seismic. To appear more slender, allow less wind exposure, and transmit more daylight to the ground, many skyscrapers have a design with setbacks, a relatively big building may be considered a skyscraper if it protrudes well above its built environment and changes the overall skyline. The maximum height of structures has progressed historically with building methods and technologies, the Burj Khalifa is currently the tallest building in the world. High-rise buildings are considered shorter than skyscrapers, the first steel-frame skyscraper was the Home Insurance Building in Chicago, Illinois in 1885. Even the scholars making the argument find it to be purely academic and this definition was based on the steel skeleton—as opposed to constructions of load-bearing masonry, which passed their practical limit in 1891 with Chicagos Monadnock Building. What is the characteristic of the tall office building.
The force and power of altitude must be in it, the glory and it must be every inch a proud and soaring thing, rising in sheer exaltation that from bottom to top it is a unit without a single dissenting line. Some structural engineers define a highrise as any vertical construction for which wind is a significant load factor than earthquake or weight. Note that this criterion fits not only high-rises but some other tall structures, the word skyscraper often carries a connotation of pride and achievement. A loose convention of some in the United States and Europe draws the limit of a skyscraper at 150 m or 490 ft. The tallest building in ancient times was the 146 m Great Pyramid of Giza in ancient Egypt and it was not surpassed in height for thousands of years, the 14th century AD Lincoln Cathedral being conjectured by many to have exceeded it
Gran Torre Santiago
The Costanera Center Torre 2, better known as Gran Torre Santiago, and previously known as Torre Gran Costanera, is a 64-story tall skyscraper in Santiago, the tallest in Latin America. It is the second-tallest building by highest architectural feature and by highest occupied floor in the Southern Hemisphere and it was designed by Argentine architect César Pelli. Gran Torre Santiago is part of the Costanera Center complex, which includes the largest shopping mall in Latin America, two hotels and two additional office towers. Gran Torre Santiago is 300 metres tall and 64 stories high plus 6 basement floors, the tower has nearly 700,000 square meters of building space available built on 47,000 square meters of land. Planners estimated that there would be some 240,000 people going to, the tower was designed by the Argentine architect Cesar Pelli of Pelli Clarke Pelli Architects, Chilean architects Alemparte Barreda & Asociados, and by the Canadian company Watt International. Structural engineering is performed by the Chilean company René Lagos y Asociados Ing, salfa Corp. was responsible for its construction.
Construction of the began in June 2006 and was expected to be completed in 2010. Construction on the project resumed on 17 December 2009 and it was expected to be inaugurated in 2013, in early November 2010, standing 205 m tall, it overtook the neighboring Titanium La Portada to become the tallest building in Chile. Structural work on the tower was completed in July 2011 and the height of 300 m was achieved on 14 February 2012. In 2013, the tower was completed, on 11 August 2015 an observation deck, called Sky Costanera, was opened to the public in floors 61 and 62, offering 360° views of Santiago. List of tallest buildings in South America Costanera Center Costanera Center website Sky Costanera - Observation deck website Brochure with technical specifications
The firm has over 14,000 staff based in 92 offices across 42 countries, and is present in Africa, the Americas, East Asia and the Middle East. Arup has participated in projects in over 160 countries, Arup is owned by trusts, the beneficiaries of which are Arups past and present employees, who receive a share of the firms operating profit each year. The firm was founded in London in 1946, as the Ove N. Arup Consulting Engineers by Ove Arup and he set out to build a firm where professionals of diverse disciplines could work together to produce projects of greater quality than was achievable by them working in isolation. In 1963, together with the architect Philip Dowson, Arup Associates was formed, in 1970, the firm reformed as Ove Arup & Partners. It is best known for its work for the built environment. Projects to which it has contributed include the Sydney Opera House,3, Nevada, USA Druk White Lotus School was built to survive the Ladakhi weather. Kingdom Centre, The third tallest skyscraper in Saudi Arabia, and the second tallest in Riyadh and this group continues to work under the banner of Arup Associates following a streamlining of the Arup brand.
Many of Arups modern stadia are designed with a contemporary, distinctive edge, the most notable stadium projects led by Arup remain the City of Manchester Stadium, Allianz Arena, Beijing National Stadium, Donbass Arena and the Singapore Sports Hub. Arups multidisciplinary sports venue design and engineering scope on the Singapore Sports Hub won the 2013 World Architecture Festival Award in the Future Projects, the Casa da Música, designed by Arup and Office for Metropolitan Architecture was nominated for the 2007 Stirling Prize. Arup was awarded the Worldaware Award for Innovation for its Vawtex air system in Harare International School, Arup Fire has won the Fire Safety Engineering Design award four times since its creation in 2001. The 2001 inaugural award was won for Arups contribution to the Eden Project in Cornwall, UK, in 2004, the design for Londons City Hall was appointed joint winner. In 2005, the Temple Mills Eurostar Depot won, the 2006 winning entry was for Amethyst House, a nine-storey building with an atrium from the ground to the top, in Manchester, UK.
Arup was awarded Royal Town Planning Institute Consultancy of the award in 2008. Mike Glover is the recipient of the 2008 Institution of Structural Engineers Gold Medal, the Evelyn Grace Academy, London designed by Zaha Hadid Architects and Arup won the prestigious RIBA Stirling Prize 2011. Arup was named Tunnel Design Firm of the Year at the 2012 ITA AITES International Tunnelling Awards, Arup Fellow is a lifelong honorary title awarded to selected honorary individuals in the firm. It acknowledges the highest design and technical achievements of people, not only within the firm and they are considered role models who possess world-class expertise who put theory into effective practice. Sir Ove Nyquist Arup, structural engineer and philosopher, founder of the company, recipient of the RIBA Royal Gold Medal for Architecture 1966, peter Dunican, structural engineer, first chairman of Ove Arup Partnership, and President of the Institution of Structural Engineers in 1977 and 1978. Sir Jack Zunz, civil engineer, and principal designer of the Sydney Opera House
Bitexco Financial Tower
Bitexco Financial Tower is a 68-Storey,262.5 m skyscraper in Ho Chi Minh City, Vietnam. At completion in 2010, it became the tallest building in Vietnam and kept this status until January 2011, Bitexco Financial Tower is owned by Bitexco Group, a Vietnamese company. The tower is owned by Bitexco Group, a multi-industry corporation, the building houses the Ho Chi Minh City office of Bitexco Group, while its headquarters are in Hanoi. The tower was designed by Carlos Zapata, Design Principal and Founder of Carlos Zapata Studio, designer Zapata, who was born in Venezuela but is based in New York City, drew inspiration for this skyscrapers unique shape from Vietnams national flower, the Lotus. The tower was inaugurated on October 31,2010. In 2013, CNN. com named the Bitexco Financial Tower one of the 25 Great Skyscraper Icons of Construction, and in 2015, Thrillist. com named the Bitexco Financial Tower the #2 Coolest Skyscraper in the World. The groundbreaking ceremony was held in September 2005, two years later, in June 2007, construction of the tower started.
The tower topped out in mid-2010 and had its inauguration ceremony on 31 October 2010, Bitexco Financial Tower is an international standard mixed use project which includes office, retail, F&B and entertainment space. At Floor 49, at height around 178 metres, there is a deck, Saigon Skydeck, open to the public daily. From floors 50 to 52, there are further F&B and entertainment offerings, including a dining restaurant. Vietnams first non-rooftop helipad is on the 52nd floor of the Bitexco Financial Tower, the helipad extends 22 meters out from the main structure. It is strong enough to carry a helicopter up to 3 tons of weight, grand Atrium Lobby Wall & Façade system The glass from Belgium was purchased and shipped to China for manufacturing. Once in China the low iron heat strengthened glass was cut into 6,000 individual panels, each panel is double glazed with the outside layer being 8mm thick and internal air space of 12mm and an internal panel of 8mm. Finally the glass was shipped to Ho Chi Minh City and the panels were installed as the building grew higher.
Each of the 6,000 sleek glass panels enveloping the Bitexco Financial Tower is individually cut to unique specifications because each floor is unique, helipad Located on the southern side of the Bitexco Financial Tower, the helipad cantilevers from the 52nd floor and resembles a blossoming lotus bud. Its installation alone took two months. Most of the used to construct the helipad were purchased from Europe and South Korea and the manufacturing took place in Bu Gang. Once the fabrication of the helipad was completed, it was shipped to Vietnam, to ensure proper assembly, the entire helipad was pre-assembled on the ground of a factory in Đồng Nai Province in Vietnam – a process that took about three weeks
The New York Times Building
The New York Times Building is a skyscraper on the west side of Midtown Manhattan, New York City that was completed in 2007. Its chief tenant is The New York Times Company, publisher of The New York Times as well as the International New York Times, construction was by a joint venture of The New York Times Company, Forest City Ratner, and ING Real Estate. The original newspaper headquarters in 1851 were at 113 Nassau Street, in a building that stood until fairly recently. The slender tower was so constricted in space that the paper outgrew it within a decade and, in 1913, moved into the Times Annex,229 West 43rd Street, where it remained for almost a century. The project was announced on December 13,2001, a 52-story tower on the east side of Eighth Avenue between 40th and 41st Street across from the Port Authority of New York & New Jersey Bus Terminal. In addition, the new building—called by many New Yorkers The New Times Tower—keeps the paper in the Times Square area, the site for the building was obtained by the Empire State Development Corporation through eminent domain.
With a mandate to acquire and redevelop blighted properties in Times Square, ten buildings were condemned by the ESDC, some owners sued, asserting that the area was no longer blighted, but lost in court. Once the 80, 000-square-foot site was assembled, it was leased to The New York Times Company, The New York Times Company received $26.1 million in tax breaks. The Times itself occupies 628,000 square feet on the 2nd to 21st floors, on December 16,2016, the New York Times announced that it was vacating at least 8 of the floors in order to generate rental income. The tower was designed by Renzo Piano Building Workshop and FXFOWLE Architects, the lighting design for the buildings nighttime identity was designed by the Office for Visual Interaction Inc. The tower rises 748 feet from the street to its roof, with the curtain wall extending 92 feet higher to 840 feet. As of 2010, the building was tied with the Chrysler Building as the fourth-tallest building in New York City, the tower is the tenth-tallest building in the United States.
The steel-framed building, cruciform in plan, has a screen of 1 5⁄8 ceramic rods mounted on the exterior of the curtain wall on the east, west. The rod spacing increases from the base to the top, adding transparency as the building rises, the steel framing and bracing is exposed at the four corner notches of the building. The new building is promoted as a green structure, the design incorporates numerous environmentally sustainable features for increased energy efficiency. The double skin curtain wall, automated louver shading system, dimmable lighting system, underfloor air distribution system, the use of floor-to-ceiling glass maximizes light and views for people inside and outside the building. The horizontal white ceramic rods on the facade, which are spaced to allow occupants to have unobstructed views while both seated and standing, act as an aesthetic veil and a sun shade. They are made of silicate, an extremely dense and high-quality ceramic chosen for its durability
85 Sky Tower
85 Sky Tower, formerly known as the T & C Tower or Tuntex Sky Tower, is an 85-story skyscraper located in Lingya District, Taiwan. The structure is 347.5 m high, an antenna increases the pinnacle height to 378 m. Constructed from 1994 to 1997, it is the tallest skyscraper in Kaohsiung, there is no 44th floor in the building, the 43rd floor connects directly to the 45th floor. The pyramid shaped crown is the equivalent of 3 stories high, there is no elevator access to floors above 80. The columns and foundation are made of steel since at 85th storey the 21MPa Ultimate compressive strength of concrete collapses, the building was designed by C. Y. Lee & Partners and Hellmuth, Obata & Kassabaum, and has an unusual design with two separate 39-floor sections, which merge into a single central tower rising to a spire. This unique design leaves a space below the central part of the tower. The design was inspired by the first Kanji and Chinese character of the citys name, john W. Milton was Project Director on behalf of Turner International Inc, a subsidiary of Turner Construction.
The building was owned by the now defunct Tuntex Group, and is mainly offices, but includes residential space, a department store, office space and studio apartment occupy each side of the lower floors. There is an Atrium that extends from Level 45s Shimmer Ballroom to 83, List of tallest buildings in Taiwan List of tallest buildings in the world Tuntex Sky Tower on CTBUH Skyscraper Center Emporis Tuntex & Chien-Tai Tower at Structurae
Empire State Building
The Empire State Building is a 102-story skyscraper located on Fifth Avenue between West 33rd and 34th Streets in Midtown, New York City. It has a height of 1,250 feet, and with its antenna included. Its name is derived from the nickname for New York, the Empire State and it stood as the worlds tallest building for nearly 40 years, from its completion in early 1931 until the topping out of the original World Trade Centers North Tower in late 1970. Following the September 11 attacks in 2001, the Empire State Building was again the tallest building in New York, the Empire State Building is currently the fifth-tallest completed skyscraper in the United States and the 34th-tallest in the world. It is the fifth-tallest freestanding structure in the Americas, when measured by pinnacle height, it is the fourth-tallest building in the United States. The Empire State Building is an American cultural icon and it is designed in the distinctive Art Deco style and has been named as one of the Seven Wonders of the Modern World by the American Society of Civil Engineers.
The building and its street floor interior are designated landmarks of the New York City Landmarks Preservation Commission and it was designated as a National Historic Landmark in 1986. In 2007, it was ranked number one on the AIAs List of Americas Favorite Architecture, the site of the Empire State Building was first developed as the John Thompson Farm in the late 18th century. At the time, a stream ran across the site, emptying into Sunfish Pond, beginning in the late 19th century, the block was occupied by the Waldorf-Astoria Hotel, frequented by The Four Hundred, the social elite of New York. The limestone for the Empire State Building came from the Empire Mill in Sanders, Indiana which is a town adjacent to Bloomington. The Empire Mill Land office is near State Road 37 and Old State Road 37 just south of Bloomington, the Bloomington and Oolitic area is known locally as the limestone capital of the world. The Empire State Building was designed by William F, the building was designed from the top down.
The general contractors were The Starrett Brothers and Eken, and the project was financed primarily by John J. Raskob, the construction company was chaired by Alfred E. Smith, a former Governor of New York and James Farleys General Builders Supply Corporation supplied the building materials. John W. Bowser was project construction superintendent, excavation of the site began on January 22,1930, and construction on the building itself started on March 17—St. Patricks Day—per Al Smiths influence as Empire State, Inc. president, the project involved 3,400 workers, mostly immigrants from Europe, along with hundreds of Mohawk iron workers, many from the Kahnawake reserve near Montreal. According to official accounts, five died during the construction. Governor Smiths grandchildren cut the ribbon on May 1,1931, lewis Wickes Hines photography of the construction provides not only invaluable documentation of the construction, but a glimpse into common day life of workers in that era. The construction was part of a competition in New York for the title of worlds tallest building
Saigon Bridge, known as Newport Bridge before 1975, is a bridge crossing the Saigon River, connecting Bình Thạnh District and District 2, Ho Chi Minh City, on the Hanoi Highway. The bridge has four lanes for cars and two lanes for motorcycles and bicycles and it was the only bridge linking District 1 to the new Thu Thiem New Urban Area in District 2 until the Thủ Thiêm Bridge opened in 2008 and the Saigon River Tunnel opened in 2011. On the morning of 30 April PAVN sappers attempted to seize the bridge but were repulsed by the ARVN Airborne, at 09,00 the PAVN tank column approached the bridge and came under fire from ARVN tanks which destroyed the lead T-54 killing the PAVN Battalion commander. The ARVN and PAVN continued to tank and artillery fire until 10,24 when the ARVN commander received President Dương Văn Minhs capitulation order over the radio. While the bridge was rigged with approximately 4000lbs of demolition charges, video showing damage to the bridge caused by a Vietcong sapper attack in May 1968 ITN report of fighting at the bridge in April 1975
The Willis Tower, built as and still commonly referred to as Sears Tower, is a 108-story,1, 450-foot skyscraper in Chicago, United States. The building is considered an achievement for its architect Fazlur Kahn. The Willis Tower is the second-tallest building in the United States, more than one million people visit its observation deck each year, making it one of Chicagos most popular tourist destinations. The structure was renamed in 2009 by the Willis Group as part of its lease on a portion of the towers space, the buildings official address is 233 South Wacker Drive, Illinois 60606. In 1969, Roebuck & Co. was the largest retailer in the world, Sears executives decided to consolidate the thousands of employees in offices distributed throughout the Chicago area into one building on the western edge of Chicagos Loop. Sears asked its counsel, Gluck, Weitzenfeld & Minow to suggest a location. This latter site was decided upon, and preliminary inquiries determined that the necessary permits could be obtained, the next step was to acquire the property, a team of attorneys from the Arnstein law firm, headed by Andrew Adsit, began buying the property parcel by parcel.
Sears purchased 15 old buildings from 100 owners and paid $2.7 million to the City of Chicago for the portion of Quincy Street that divided the property. Their team of architect Bruce Graham and structural engineer Fazlur Rahman Khan designed the building as nine square tubes, all nine tubes would rise up to the 50th floor of the building. At the 50th floor, the northwest and southeast tubes end, at the 66th floor, the northeast and the southwest tubes end. At the 90th floor, the north and south tubes end, the remaining west and center tubes continue up to the 108th floor. The Willis Tower was the first building to use Khans bundled tube structure and this innovative design was structurally efficient and economic, at 1,450 feet, it provided more space and rose higher than the Empire State Building, yet cost much less per unit area. This structural system would prove influential in skyscraper construction. It has been used in most supertall buildings since then, including the worlds tallest building, to honor Khans contributions, the Structural Engineers Association of Illinois commissioned a sculpture of him for the lobby of the Willis Tower.
The latter floor areas had to be designed to a plate, with a high window-space to floor-space ratio, to be attractive. Smaller floorplates required a structure to yield sufficient square footage. The height was restricted by a limit imposed by the Federal Aviation Administration to protect air traffic, the financing of the tower was provided by the Sears company. It was topped with two antennas to permit local television and radio broadcasts and the City of Chicago approved the design, and the first steel was put in place in April 1971