Skyscraper! Achievement & Impact, Liberty Science Center – Jersey City, New Jersey
Recently we had the pleasure to visit the Skyscraper! exhibition at the Liberty Science Center in Jersey City, New Jersey. A few key excerpts from the exhibit follow.
What is a skyscraper?
Tall buildings are forged from human aspiration, science and engineering. They change peoples’ perceptions of their world and are part of our sustainable future.
It’s more than just a structure
What is it about a building that earns it the name “skyscraper”? Experts don’t always agree. It could be the technology, such as the elevators or steel frame. Or perhaps it’s the structure’s most recognizable feature – the height.
Elevators: Perhaps these are the key to skyscrapers. A building needs them to have lots of floors. But as early as 1850, short buildings had elevators. Is that enough to take elevators out of the skyscraper definition?
Height: Everybody agrees on this distinctive feature. These buildings got their name because their tops scrape the sky! But who decides what’s tall enough to make a skyscraper?
Interior space: Here’s something else people agree on. A skyscraper has interior space where people live or work.
Frame: A frame is one key feature. The frame, made of steel, concrete and other materials, supports the floors and walls. It also allows thin materials like glass to be used on the exterior. But experts say that some heavy masonry buildings are skyscrapers, too.
Sky-High Style
A skyscraper’s style is all in the details
Skyscrapers have style. Each one is a product of the culture, tastes and technologies of its time. You’ll see these reflected in the building’s shape, materials and ornamentation. If you can identify the style, you can guess when a skyscraper was built.
One example is Art Deco, with its sleek lines, bold geometric shapes and mix of colors. Identify these details and you know the building probably dates from the 1920s or 1930s. See if you can pick out the unique styles of some skyscrapers the next time you visit a city.
Chicago School, 1880s-1920s: This style features large windows in a grid pattern and little exterior ornamentation.
Art Deco, 1920s-1930s: This building has the bold streamlined look of the Art Deco style.
Modernism, 1940s-1970s: Simple designs and lots of glass identify this skyscraper style.
Curtain Wall
This innovation has changed the face of skyscrapers
A curtain wall is an external surface that hangs from a skyscraper’s steel or concrete skeleton the way a curtain hangs from a rod. It’s decorative, but it also protects the building from outside weather.
Before steel skeletons, tall buildings were made by piling up heavy stone or brick walls to support the weight of many floors. A curtain wall doesn’t support the building, so a designer can make it any shape, size or material imaginable. A smooth glass curtain wall is a hallmark of many skyscraper.
Modular panels: Because the curtain wall doesn’t support the building’s weight, it can be hung on the framework like this one on The New York Times office building. Some panels are built piece by piece right onto the skyscraper, while others are manufactured with windows in a frame of mullions, shipped to the site and attached.
Infill: Large, flat panels called infill made upn most of a curtain wall. Sometimes these are thin sheets of brick, stone, metal or plastic. The most popular infill is glass, because it fits the clean design favored by many architects. Glass lets people see out and sunlight stream in.
Mullions: Long, thin strips called mullions form a grid to hold the infill. Aluminum and other metals are most often used. However, metals expand and contract when heated or cooled. This can make the curtain wall change size or deform with changes in weather. Expansion joints, or spaces in the mullions, let the metal move without affecting the curtain wall.
Beams and Columns
The strongest beams and columns have I, T and C shapes
Just as you have a skeleton to support your muscles and organs, a skyscraper has a rigid frame to support all its floors and materials. Beams and columns made of steel or concrete attach to each other and hold the building upright.
Forces of nature constantly push and pull on a skyscraper. The frame has to be strong enough to resist them. There’s a beam, or column to withstand every force, from wind to weight to earthquake.
Flat beams are weaker: Apply pressure to these beams and the upper part gets squeezed (compressed) while the bottom part gets stretched (). The thinner the beam, the more it buckled and bends. A frame made with simple beams wouldn’t be strong.
Shaped beams are strong.
Power and Data
These utilities are vital to skyscraper life
Power and data from the city come into the building through the basement. Pipes called conduits support and protect the electrical and data cables that run up through the core. At electrical and data closets on each floor, the cables are connected to branch lines that reach all the spaces where people live or work.
Because skyscrapers use so much electricity, many architects and engineers look for renewable alternatives that cause less pollution than power plans burning oil or coal. These include photovoltaic cells, fuel cells and wind turbins, which turn sunlight, gas and wind into electricity.
Electrical closets: The conduits connect to electrical closets on each floor. The power is distributed to each floor through a set of transformers.
Data closets: The data conduits come to this closet on each floor. From there, conduits beneath the floor or above ceilings distribute data cables to offices and apartments.
Power: Conduits distribute power up and down the core.
Data: Conduits distribute data up and down the core.
Source: Power and data from the city enter the building’s basement.
Electrical room: Here, transformers and switches connect the power and data lines from the street to the rest of the system.
Newer skyscrapers use this precious resource more efficiently
No one could live or work in a skyscraper for long without water. Bottom to top, these giants pump in clean water, pump out wastewater and maintain fire-fighting sprinklers.
Green skyscrapers manage water better than older buildings. Their systems are designed to waste less water and clean it more thoroughly before it returns to the city’s water system.
Water tower: Clean water collects in the tower for use in the upper floors. Gravity helps the water reach sinks, toilets and showers.
Tanks: Several tanks halfway up the building collect water and distribute it to lower floors.
Pipes: These distribute water throughout the building. There are different groups of pipes for clean water, wastewater and sprinkler systems.
Wastewater: Wastewater from sinks is often used to flush toilets. All the water used in the building eventually ends up in the city sewer system.
Waste pipes: Wastewater leaves the building through pipes that are ventilated wide and especially strong. The partially solid waste carried by this water could block narrower pipes. The ventilation reduces pressure that could pull or push wastewater back out of the pipes.
Sewer: Wastewater from upper floors empties directly into city sewers…
Heating, ventilating and air-conditioning (HVAC) systems keep occupants comfortable
A curtain wall isolates a skyscraper’s interior from the outside. This makes it easier to control the inside temperature but harder to keep fresh air flowing through the building. The HVAC system helps inhabitants stay comfortable and breathe easily.
Ventilation is key to keeping a building livable. Plenty of fresh air and good circulation keep fumes from concentrating and bacteria from spreading. Improper airflow can make people sick. With “sick building syndrome,” the germs from one ill person travel through the ventilation system to infect people throughout the building.
Cooling tower: Warm water carrying heat out of the building is sprinkled through outside air. As some water evaporates, the rest is cooled, ready to accept more waste heat.
Supply and return ducts: These distribute the cold or hot air through each level of the building.
Chiller: This cools the water used in the air-conditioning system.
Boiler: The boiler heats the water used to keep the building interior warm.
Fans: These push hot or cool air in and out of the ducts.
Pumps: These push water up the building.
Elevators
Innovative designs move people up and down more efficiently
All skyscrapers need elevators. Very tall buildings need complex computerized systems to move people as quickly as possible. These often include express elevators and multi-deck cabs.
In the most advanced skyscrapers, people who ride on one of the shuttle elevators can go from ground floor to top floor in about half a minute. That’s over 37 mph! Double-deck cabs carry twice as many people as regular cabs, taking up less space in office buildings.
Mechanics: The main elevator equipment is located above the shaft.
Crossover: Local elevators start and end on the floors where express elevators stop. This way one can take the express half way and then a short local to the final destination.
Decks: Multiple decks, or cabs, can move more people at a time.
Local: These cabs can stop at each floor. They start and end on floors where the express elevators stop.
Core
All the mechanical systems branch out from here
Like a vertical tunnel, the core runs up the building’s center from basement to roof, it helps support the skyscraper and moves people, air, water and electricity between floors. Look here for stairs, elevators, plumbing pipes, electrical conduits and fire and safety devices.
Plumbing ‘Risers’: These pipes run up inside the core. They bring water to branch lines on each floor.
Embedded Energy
Each phase of work adds to the total energy required to build a skyscraper
Source: Extracting material from its original source, such as mining, can be expensive. Recycled materials require no mining and result in less pollution.
Shipping: It costs something to ship materials. A long journey adds more to the cost of the product. All methods of transportation give off polluting emissions, some more than others.
Manufacturing: Materials are turned into products at factories. Production processes can sometimes be environmentally harmful which increases the embodied energy of the material.
Assembly: Products get assembled either in factories or at the construction site. The transportation cost and the assembling processes can add to the cost.
Durability: The longer a material lasts, the less new material has to be produced. Durable materials have lower embodied energy costs.
Lumber
Brick
Glass
Recycled Steel
Recycled Aluminum
Concrete
Plastic
Steel
Aluminum
“Skyscrapers will be a crucial part of a much needed sustainability strategy for… a reduced carbon footprint. Tall buildings will need to respond to variable conditions around them. The building and its systems will change at different times of the day and with the seasons; it will adjust to the amount of people and activity in it. Rather than standing in opposition to nature, the skyscraper of the future will blur and meld the natural and built environments.” – Dan Kaplan, FXFowle Architects