The Design, History, Interesting Facts and Havoc of Really Tall Buildings

Tall Tales

By definition a ‘Skyscraper’ is a building that reaches up past those around it and changes the skyline. People often describe a very tall building as a skyscraper but the definition can actually apply to a structure as low as four stories – as long as it reaches past the surrounding built environment and changes the skyline, it is considered a skyscraper. These buildings can also be incredibly tall and can be used for anything, commercial or residential; these are the types of skyscrapers that will be focused on in this piece.

Most post-1960’s skyscrapers are made of a heavy steel frame, dropped into place and welded by iron workers. Rather than load bearing concrete walls, the steel frame bears the load and simple concrete curtain walls or windows are hung in place. Not only does this provide a very flexible yet strong end product, it makes the construction of these beautiful masterpieces a quick process. The problem is that the higher you get when building a structure of this type, the more support material you need for the building to maintain its strength, leaving less floor space in the process. These buildings do not often reach past 40 stories.

In 1960, an architect named Fazlur Rahman Khan designed the world’s first building to use a tube system, which is a building designed to resist lateral loads by acting as if it is a three-dimensional hollow tube anchored to the ground. This world’s first was the 43 storey Dewitt-Chestnut Apartment Building in Chicago, Illinois, USA, and it was completed in 1963. The exterior is designed with squares and triangles to will resist any pressure that may be pushing on it from the outside environment, while the inside floors and walls do not need to provide any structural support whatsoever. These buildings can be straight up and down, or they may consist of many tubes of different heights tied together like the Willis Tower (formerly Sears Tower) which was the world’s tallest building from its completion in 1973 through to 1998 when the cylindrical Petronas Towers were built.

From here we will begin a journey into some of the world’s most extraordinary buildings starting from the not-so-tall to the very tallest building ever built by man. We will explore design, history, interesting facts and what can go wrong.

One of the most well-known structures in the world is The Empire State Building which is named after New York’s nickname ‘The Empire State.’ It was completed in 1931 and was the tallest building in the world at 102 stories. It has a roof height of 1,250 feet and with the pinnacle included, 1,454 feet. The building was designed by William F Lamb and was drawn up in two weeks by modifying earlier designs already built in other parts of the United States. This building was designed from the top down as opposed to foundation to sky, and involved 3,400 workers, five of whom died during the construction. The building took 18 months to build and cost $24.7 million – the equivalent of $372.8 million USD today.

Inside, there are 85 stories of commercial and office space, and on the 86th floor is an observation deck from which one can see most of New York City. The rest of the building is dedicated to an Art Deco tower and capped with another observatory on the 102nd floor. Atop the tower is a 203 foot pinnacle, largely covered with broadcast antennas and a lightning rod that sits at the very top. This building, the first in the world to have over 100 floors, has 6,500 windows, 73 elevators and 1,860 steps from ground level to the 102nd floor. It has a total floor area of 2,768,591 square feet and the base is two acres across. This building is so big, in fact that it has its own post code, 10118. The Empire State building houses 1,000 businesses which employ about 21,000 employees.

Upon entering the Empire State Building and finding an elevator, it takes under a minute to reach the gift shop on the 80th floor. The building has 113 kilometres of pipe, 760,000 meters of electrical wiring and just over 9000 faucets. It is heated by hot steam that flows to the very top of the building to keep occupants toasty warm. In the 1933 film, King Kong this was the building climbed by the giant lovesick ape. It has recently been given a $550 million dollar face lift to improve its eco-footprint, and now boasts a more eco-friendly and energy efficient structure.

Even though this building was built before the tube system was first used to increase tall building stability, it was so well built that it survived a B-25 Mitchell airplane crash at 9:40am on Saturday, July 28, 1945 that destroyed the 79th and 80th floors. One of the plane’s massive engines shot clear through the building, out the opposite side and landed two blocks away on the roof of another building, starting a fire that destroyed an entire penthouse. The other engine and part of the landing gear flew into the core of the building, where they fell down an elevator shaft. This incident killed 14 people which could have easily been 15; an elevator operator named Betty Lou Oliver somehow survived a 75 storey plunge inside an elevator. The building was open for business the following Monday.

The International Finance Centre is a commercial development on the waterfront in Hong Kong’s Central District. It was designed by Cesar Pelli who is known for designing a few other very tall buildings, including the World Trade Center towers that once stood in New York City. Completed in 2003, this building has a tapered look and is shaped like a javelin that stretches 88 floors above the ground. It is covered in lightly reflective glass panels and pearl coloured mullions. The floor plan is wide open, with few columns to take up space with most of the building’s structure and services situated within its central core. This building was built equipped with everything needed to be a fully functional business powerhouse. There are fibre-optics, wifi, satellite networks and trading floors. Another interesting feature is that the building is actually cooled by sea water. Its 62 high-speed, double-decker elevators will come and get you in an average of 30 seconds. IFC Two was built during the aftermath of 9/11 and the event sparked a plan to inspect the building and revamp the plans such that it could be evacuated in under 30 minutes. As a result, the building is not only one of the tallest buildings in the world, but also one of the safest.

Back in New York City, there are, of course, a couple of ghosts that stand tall in everyone’s memory – the remnants of two giant buildings that were the site of a devastating terrorist attack.

Designed in the early 1960s by an architect by the name of Minoru Yamasaki and Associates of Troy, Michigan and Emery and Sons of New York, the twin World Trade Center towers used the tube system design that allowed them to stand taller than any building around at a giant 110 stories. The first shovel of dirt was sunk into the ground on August 5th, 1966 and it took until December 1972 to complete the North building; a few months later, in July of the next year, the South building was completed. These buildings cost $400 million USD to build, about $2.3 billion in today’s USD. These buildings were located right in the heart of the financial district and offered 13.4 million square feet of office space. On the 106th and 107th floors of the North Tower was a restaurant aimed at tourists, and in the other building there was an observation deck on the 107th floor. Together, the WTC buildings had 95 express and local elevators that were designed in such a way that more than one elevator could use the same shaft; this design was to limit the amount of space used up by elevators.

The design called for 18 inch windows all along the building’s walls. The structural engineering firm Worthington, Skilling, Helle & Jackson worked to implement Yamasaki’s design, developing the tube-frame structural system used in the twin towers. The tube-frame design, earlier introduced by Fazlur Khan, was a new approach that allowed more open floor plans than the traditional design that distributed columns throughout the interior to support building loads. The World Trade Center towers used high-strength, load-bearing perimeter steel columns called Vierendeel trusses that were spaced closely together to form a strong, rigid wall structure, supporting virtually all lateral loads such as wind forces, and sharing the gravity load with the core columns. The perimeter structure containing 59 columns per side was constructed with extensive use of prefabricated modular pieces, each consisting of three columns, three stories tall, connected by spandrel plates. The spandrel plates were welded to the columns to create the modular pieces off-site at the fabrication shop. Adjacent modules were bolted together with the splices occurring at mid-span of the columns and spandrels. The spandrel plates were located at each floor, transmitting shear stress between columns and allowing them to work together in resisting lateral loads. The joints between modules were staggered vertically so the column splices between adjacent modules were not at the same floor.

The core of the towers housed the elevator and utility shafts, restrooms, three stairwells, and other support spaces. The core of each tower was a rectangular area 87 by 135 feet and contained 47 steel columns running from the bedrock to the top of the tower. The large, column-free space between the perimeter and core was bridged by prefabricated floor trusses. The floors supported their own weight as well as live loads, providing lateral stability to the exterior walls and distributing wind loads among the exterior walls. The floors consisted of four inch thick lightweight concrete slabs laid on a fluted steel deck. A grid of lightweight bridging trusses and main trusses supported the floors. The trusses connected to the perimeter at alternate columns and were on six foot, eight inch centres. The top chords of the trusses were bolted to seats welded to the spandrels on the exterior side and a channel welded to the core columns on the interior side. The floors were connected to the perimeter spandrel plates with ‘viscoelastic dampers’ that helped reduce the amount of sway felt by building occupants.

Hat trusses (or “outrigger trusses”) located from the 107th floor to the top of the buildings were designed to support a tall communication antenna on top of each building. Only 1 WTC (north tower) actually had an antenna fitted; it was added in 1978. The truss system consisted of six trusses along the long axis of the core and four along the short axis. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower.

Another cool idea was that the tube frame design using steel core and perimeter columns protected with sprayed-on fire resistant material created a relatively lightweight structure that would sway more in response to the wind compared to the Empire State Building with its thick, heavy masonry for fireproofing of steel structural elements. During the design process, wind tunnel tests were actually done to establish design wind pressures that the World Trade Center towers would be subjected to and the structural response to those forces. Experiments were also conducted to evaluate how much sway occupants could comfortably tolerate; however, many subjects still experienced dizziness and other ill effects. One of the chief engineers, Leslie Robertson worked with Canadian engineer Alan G. Davenport to develop viscoelastic dampers that would absorb some of the sway.

On Feb 13th, 1975 the North Tower survived a three alarm fire that burned the 9th, 11th and 14th floors by spreading up and down insulated telephone cables that ran up and down the core. In 1992, a Ryder rental truck loaded with 1500 pounds of explosives was detonated in the underground parking lot. The blast opened a 100 foot hole through five sublevels, with the greatest damage on B1 and B2 as well as some significant structural damage on level B3. Six people were killed and 50,000 people were forced to evacuate down unlit stairwells that contained no emergency lighting, some taking nearly two hours to reach safety. In January 1998 the Bank of America was robbed by a three man crew that made off with two million dollars. These buildings were destroyed in 2001 when a well trained terrorist crew hijacked two planes and flew them into the sides of each building, hitting important structural elements and igniting natural gas and jet fuel that burned uncontrollably. These buildings were not designed for evacuation, though they had been designed with plane crashes in mind; even so, the buildings both collapsed, killing at least 2,753 individuals.

For more in our continuing Tall Buildings series, look for next month’s issue of Construction in Focus.

Home Automation

Call it ‘domotics,’ and you are likely to receive a blank stare, but refer to it as ‘smart home’ or ‘home automation,’ and you will get a nod of acknowledgement. For the past few years, consumers have heard the word ‘smart’ attached to countless products and services, from food and drink to snacks like popcorn and mobile phones, which no one seems to refer to as a ‘cellphone’ anymore. Yet what, exactly, constitutes ‘smart’?

January 17, 2019, 6:11 AM AEDT