How Skyscrapers Work ( Introduction)

Throughout the history of architecture, has been a constant search for the height. Thousands of workers working in the pyramids of ancient Egypt, the cathedrals of Europe and a host of other towers, all trying to create something impressive. People build skyscrapers primarily because they are convenient - you can create a lot of real estate a relatively small land area. But ego and grandeur often play an important role in the field of construction, as it did in earlier civilizations.

Until relatively recently, we could only go as high. After a certain point, it simply was not possible to continue building up. In the late 1800s, new technology is redefining the boundaries. Suddenly, it was possible to live and work in colossal towers, hundreds of feet above the ground.

The Twin Towers

When the twin towers of World Trade Center were hit on September 11, 2001, seemed at first that could remain standing. But in less than two hours, both towers had collapsed on the floor.

The fight against gravity

The main obstacle in building up the force of gravity. Imagine carrying a friend on his shoulders. If the person is fairly light, can help quite well for itself. But if I had to put someone else on the shoulders of his friend (build your tower higher), the weight would probably be too much for you to carry alone. To make a tower that is "high-multiple people," it takes more people at the bottom to support the weight of the world above.

The Empire State Building in New York. The view from the 86th floor observatory is building one of the main attractions of New York.

In normal buildings made of bricks and mortar, you have to keep a lower wall thickening as the construction of new upper floors. After reaching a certain height, this is very impractical. If there is almost no space on the lower floors, which is the point in making a tall building?

Using this technology, people are not building many buildings over 10 stories - was not feasible. But in late 1800, a number of converging developments and circumstances, and the engineers were able to break the upper limit - and then some. The social circumstances that led to the skyscraper were the growing metropolitan centers of America, especially Chicago. Businesses all wanted their offices near the city center, but there was enough space. In these cities, architects needed a way to extend the metropolis upward instead of outward.

The main technological advance that made skyscrapers possible was the development of mass iron and steel production (see How Iron and Steel Work for details). The new manufacturing process has helped produce long beams of solid iron. Essentially, this gave architects a new set of basic elements to work with them. Narrow, relatively lightweight metal beams could support much more weight than the brick walls in older buildings, while a fraction of the space. With the advent of the Bessemer process, the first efficient method for mass production of steel, the architects moved away from iron. Steel, which is even lighter and stronger than iron, has allowed to build even taller buildings.

Grids giant beam

The central support structure of a skyscraper is its steel skeleton. Metal riveted beams end to end to form vertical columns. At each floor level, these vertical columns are connected to the beam horizontal beams. Many buildings have diagonal beams running between the beams, as additional structural support.

This giant three-dimensional grid - called the super structure - all the weight on the building are transferred directly to the vertical columns. This concentrates the downward force caused by gravity in relatively small areas where the columns rest at the base of the building. This concentrated force is then spread out underneath the building infrastructure.

In a typical skyscraper substructure, each vertical column sits on an equal spread. The column rests directly on a cast iron plate that sits on top of a grid. The grid is basically a stack of horizontal steel beams, lined side by side in two or more layers (see diagram below). The grid rests on a thick concrete slab directly on the hard earth beneath the earth. Once the steel is in place, the whole structure is covered with concrete.

This structure expands out lower on the ground, in the same way a pyramid extending outward as you lower. This distributes the concentrated weight of the columns on a wide area. Ultimately, the full weight of the building sits directly on the hard clay material under the ground. In very heavy buildings, the basis of mass media other pillars of concrete footings that extend all the way to the rock layer of the earth.

An important advantage of the steel skeleton structure is that the exterior walls - called the curtain wall - just support its own weight. This allows the architects of the building open as much as they want, in marked contrast to the thick walls of traditional buildings. In many skyscrapers, especially those built in the 1950s and '60s, the curtain walls are made almost entirely of glass, giving the occupants a spectacular view of the city.

Making it functional

In the last section, we saw that the iron and steel making new process opened the possibility of tall buildings. But this is only half the picture. Before skyscrapers skyscraper could become a reality, engineers had to be practical.

73 The Empire State Building elevator can move 600-1400 feet (183-427 meters) per minute. A maximum speed, you can travel from the lobby to the 80th floor in 45 seconds.

Once you get more than five or six floors, stairs become a fairly inconvenient technology. Skyscrapers would never have worked without the coincident emergence of the technology of the elevator. From the passenger elevator was installed first in Haughwout department store in New York in 1857, elevator shafts have been an important part of designing skyscrapers. In most skyscrapers, the elevator shafts are the core of the building.

By deciphering the structure of the elevator is a balancing act of sorts. As you add more floors of a building to increase the occupancy of the building. When more people obviously need more elevators or the lobby will fill up with people waiting in line. But elevator shafts occupy much space, so you lose floor space for every elevator you add. To make more room for people, you have to add more plants. Deciding on the appropriate number of floors and elevators is one of the most important parts of a building design.

Building safety is also an important consideration in the design. Skyscrapers would not have worked so well without the advent of new building materials resistant to fire in 1800. These days, skyscrapers also equipped with sophisticated spray equipment that puts out most fires before they spread very far. This is extremely important when you have hundreds of people who live and work thousands of feet above a safe exit.

Architects also pay special attention to the comfort of building occupants. The Empire State Building, for example, was designed so that their occupants would always be within 30 feet (ft) from a window. The building of the Commerzbank in Frankfurt, Germany has tranquil indoor garden areas built in front of the building office areas, a climbing spiral structure. A building is only successful when the architects have focused not only on structural stability, but also usability and occupant satisfaction.

Wind Resistance

In addition to the vertical force of gravity, skyscrapers also have to deal with the horizontal force of the wind. Most skyscrapers can easily move several feet in any direction, like a swaying tree, without damaging its structural integrity. The main problem with this horizontal movement is how it affects the people inside. If the building moves a substantial horizontal distance, the occupants will undoubtedly feel.

The most basic method for controlling horizontal roll to just tighten the structure. At the point where the horizontal beams attached to the vertical column, bolts of the construction crew and solder them on the top and bottom and side. This move makes the whole steel super structure more like a unit, as a stick instead of a flexible skeleton.

The Chrysler Building in New York.

For tallest skyscrapers, tighter connections do not really do the trick. To maintain these buildings to sway in large measure, the engineers have to build particularly strong core through the center of the building. The Empire State Building, Chrysler Building and other skyscrapers of that time, the area around the central axis of the lift is reinforced by a sturdy steel frame, braced with diagonal beams. Most recent buildings have one or more cores of concrete built in the center of the building.

Making buildings more rigid also braces against earthquake damage. Basically, the entire building moves with the horizontal vibration of the earth, so the steel skeleton is not twisted and strained. While this helps protect the structure of skyscrapers, you can be pretty rough with the occupants, and can also cause much damage to furniture and loose equipment. Several companies are developing new technologies to counteract the horizontal movement to dampen the strength of the vibration. For more information on these systems, check out how smart structures will work.

Some buildings already use advanced shock absorbers compensating for wind. Citicorp Center in New York, for example, uses a tuned mass damper. In this complex system of hydraulic oil systems push a weight of 400 tonnes of concrete and back in one of the top floors, shifting the weight of the entire building from side to side. A sophisticated computer system carefully monitors how the wind is changing the building and moves the weight accordingly. Some similar systems of the building weight change based on the movement of giant pendulums.

The vertical variations

As seen in previous sections, the skyscrapers of all shapes and sizes. The concept of steel frame makes for a very flexible structure. The columns and beams are like a giant erector set pieces. The only real limit is the imagination of architects and engineers to put the pieces together.

Onward and upward

The world's tallest "title passes regularly from skyscraper to skyscraper. This is one of the most competitive contests in construction. Architects and engineers wholeheartedly embrace the challenges of building higher, and businesses and cities are a popular choice for the glory of dominating the competition. The current champion is the Petronas Towers in Malaysia (see box on previous section.)

In all respects, the race is far from over skyscrapers. More than 50 proposed buildings that would break the current record. Some of the most conservative structures already under construction. But the most ambitious buildings in the group are only theoretical at the moment. Is it possible? According to some experts in engineering, the real limitation is money, not technology. Super tall buildings that require heavy-duty materials and deep, fortified bases. The workers need to develop cranes and pumping systems to get materials and concrete to the upper level. In total, putting one of these buildings could easily cost tens of billions of dollars.

In addition, there would be logistical problems with the elevators. To make the upper floors of a building with 200 floors, easy access, you would need a large bank of elevators, which occupy a large area in the center of the building. An easy solution to this problem is to fix the elevators so that only up to cover part of the building. Passengers who want to go to the top will lift halfway down and then take another elevator the rest of the road.

Experts are divided about how high you can really go in the near future. Some say it could build a kilometer high (5,280 feet or 1. 609 m) development with existing technology, while others say they would need to develop lighter, stronger materials, faster elevators and advanced control dampers before these buildings were viable. Hypothetically speaking, most engineers will not impose an upper limit. Future advances technology could lead to sky-high cities, many experts say, housing a million people or more.

Whether it will actually arrive is another matter. We may be forced to build higher up in the future, just to keep their land. When it builds up, you can concentrate more on the development of an area, instead of distributing natural areas untapped. Skyscraper cities are also highly desirable: Most companies can be grouped in a city, reducing commuting time.

But the main force behind the skyscraper race could become the vanity base. When the height monumental, once the gods and kings honored, now glorifies corporations and cities. These structures come from a very basic desire - everyone wants to be the largest building in the block. This unit has been an important factor in the development of skyscrapers in the last 120 years and is a good bet to continue to push the buildings in the coming centuries.

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