Structures
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(A)
STRUCTURES

Anything that has shape has structure. A tree is larger at the bottom not only so that at it can support it's own weight, but to maximize it's ability to gather light by allowing the sunlight a chance to shine on the bottom leaves. It's leaves have their stems branch through out the leaf to support it's broad surface needed to catch the light. Nature provides us with many beautiful and complex structures such as spider webs and beaver dams, of which both combat great forces and provide habitat.
Man, like Mother Nature, builds many different types of beautiful and complex structures for various purposes. Each of these structure has to over come it's own type of barriers.
Some of the secretes that led to human engineering accomplishments have been lost. Often we learn from the lessons that Mother Nature has provided for us on how to deal with the forces and barriers that challenge us onward.
Sometimes Mother Nature challenges us with unforeseen problems.

The thing is, for so many of us; often we either take for granted, or simply donít take the time to consider, the enormous accomplishment and social impact the many structures of the world present. Perhaps if we were to consider the gigantuate amounts of material, enormous costs, time, manpower and ingenuity, let lone the risks or barriers to over come; perhaps then we might begin to consider how big-a-deal, how significant, how cool, these structures really are.

To view previous CBHA Structure building champs, click: http://www.cbhatech.ednet.ns.ca/teched9/

Lets test ourselves by guessing the answers to the following questions: (Write them down on a piece of paper)
Activity: Test Your Knowledge

a.) In 1776, the completion of an Underground Canal joining Lancashire County and Manchester, England for the purpose of transporting coal actually led to lowering the price of coal by half. How long do you think this over 250 year old, hand dug tunnel is?

b.) The Hoover (Hydroelectric power) Dam built in 1936, in Arizona and Nevada, USA has enough cement in it to build a four-foot-wide sidewalk that, if started at the Congo ( on the equator) at the east side of continent of Africa, and went westward towards Kenya ; Where would you end up?

c.) How many tons would you say the Toronto Sky Dome retractable roof weighs?

d.) How many windows do think are in the 88 story Petronas (twin)Towers Located in Kuala Lumpur, Malaysia which were completed in 1998 at a cost of $1.6 billion.

e.) The Akashi Kaikyo Suspension Bridge completed in 1988, joining Kobe and Awaji-shima, Japan, at a cost of $4.3 billion, by the way, has cables that, if put end to end, would go how many kilometers?
 

Did you imagine that a 250 year old underground canal was any where near 274,560 feet (52 miles) in length? Can you believe that the cement in the Hoover dam would build such a sidewalk that would rape around the earth's equator and bring you back to the Congo? Did you really think that the Sky Dome's roof weighs more than 11,000 tons, and that the roof panels slide at a whopping rate of 71 feet per minute? How would you like to clean the Petronas Tower's 32,000 windows. It takes window washers an entire month to wash each tower just once! The length of the cables used in the Akashi Kaikyo Bridge totals 300,000 kilometers. That's enough to circle the earth 7.5 times! Now that has to be impressive. for more impressive structures, click on the following link. Check out the fast facts at the bottom of each link.
http://www.pbs.org/wgbh/buildingbig/wonder/structure/browse.html

Exercise A: Let's try out the following scavenger hunt and hopefully gain a little more awareness and appreciation for structures in general. The answers can be found by clicking on the appropriate links below ( Tunnels Dams Domes Skyscrapers ), and searching through the related information.

Scavenger Hunt

Before you begin this exercise, you are to take a page, divide it down the middle into two columns . Then go through the questions below and in the left column; answer questions to the best of your ability. Once you "guess" them all, use the links below to find the correct answers, and record the correct answers in the right column. Finally, compare the results. You may be surprised at what you find.

Tunnels Dams Domes Skyscrapers

  1. What are the 3 different types of manmade tunnels?
  2. What are the 3 general stages of tunnel construction?
  3. How much 1" dia. reinforcement steel will be required to complete "The Big Dig".
  4. How long is the longest roadway tunnel in the world? The almost 32 mile long Euro tunnel joining France and England was quit an accomplishment, but there exists 4 railway tunnels in the world that are longer. What country holds the title for having the longest?
  5. What are the 4 main kinds of man made dams?
  6. What type of dam requires the least amount of material to build?
  7. What is done to the steel in pretension concrete that is different than regular reinforced concrete?
  8. When was the first masonry dome erected?
  9. When did metal ribs begin to replace masonry ribs?
  10. What type of dome is a partial sphere shape structured from a series of triangles, rather than a series of arches.
  11. How fast does the retractable roof at Sky Dome move?
  12. All told, what was the bill for Montreal's Olympic Stadium?
  13. What was the the first tall building to be supported by a steel skeleton?
  14. When was the installation of the first passenger elevator?
  15. How much paint does it take to paint the Eiffel Tower?
  16. Approximately how many times a year is the Empire State Building struck by lightning each year?
  17. How deep was the foundation of the World Trade Center?
  18. How many people were the elevators of The World Trade Center designed to carry?
  19. How much telephone wire is contained within the Sears Tower.
  20. The Empire State Building robbed The Chrysler Building of the title for being the tallest skyscraper in the world in 1931, World Trade Center quickly lost the title to The Sears Building in the 70's. Who holds the title now?

(B)

So, let's begin looking at structures from the ground up, or even below. In getting back to nature, we, like many rodents and other animals, dig tunnels and build dams to protect our habitat and food source.
Manmade dams may have more varied purposes for being built compared to the famous beaver, but the forces working on them are similar, as are some of the negative results of a new dam.

Man made dams are controversial because of the costs verses the benefits of any Dam. The costs are not always measured in dollars. Nova Scotia protects fertile land in the Canning area with dams called dykes. Holland's dykes keep over 1/2 the country protected from serious flooding. In Sept./05, New Orleans experienced the costs when the levees (a kind of dam), meant to protect the city, were not sufficient to hold back Mother Nature.

Tunnels are structures that are somewhat unique in comparison to above ground structures largely due to the barriers and forces they have to deal with. People also tunnel under ground like many animals do for various reasons. In our case it may be to mine ores and minerals, or simply to get from one place to another.

Exercise B:

1) List 4 major advantages as well as 4 disadvantages of manmade dams.

2) Dams don't last forever. Hot and cold weather makes them crack. Water erodes their foundations. They create environmental problems. Eventually, there becomes a time when difficult decisions have to be made; every dam must be repaired, removed, or replaced. On the surface, this may seem to be a simple decision to make, but if you investigate the 4 dam scenarios below, you will see that things always cut and dry. Click on the following link and solve the various dam problems, but make sure you check out all the possible answers: http://www.pbs.org/wgbh/buildingbig/dam/challenge/index.html

3) From what you have seen concerning tunnels, why do you think people build tunnels?

4) Digging tunnels is hot, dirty, and a risky business. Since ancient times, tunnel diggers have used different types of tools and techniques to carve through mountains and bore through oozing mud. We have seen the 3 types of tunnels and the 3 stages it takes to produce a tunnel. Now lets try solving the three tunnel challenges on this link: http://www.pbs.org/wgbh/buildingbig/tunnel/challenge/index.html
NOTE: Check out the different options for each condition, including the unlikely choices to learn some valuable and interesting information.

This is a good time to watch the Euro Tunnel video.

(C)

Most man made structures: bridges, towers, buildings such as skyscrapers and domes , are not only classified as structures, but also as works of art. They can be very complex and are all built to deal with great forces. . For the purpose of this program, we are going to concentrate on bridges as a means to better our engineering skills and our appreciation for the work and know how involved in producing the structures that we, perhaps, take for granted. Before we get into bridges, however, let's take a last quick look at skyscrapers and domes.
Many buildings , especially skyscrapers are built in earthquake zones, and are designed to handle these violent tremors, as a result.

http://www.glasssteelandstone.com/TheBuildings.php

Exercise C:

1) Watch or this series of videos: , (a segmented version, which has some over lap). Then answer the following questions.

a) How did skyscrapers get started? How do they differ from today?

b) What are 2 benefits to skyscrapers, and 6 major problems (3 structural & 3social) that skyscrapers present?

This is a summarized review of the above subject.

2) It's your job to investigate three damaged buildings and figure out how to fix them ... fast! Click on the following link and check out all the options for each one.
The Skyscraper Challenge


3) Follow the link below to solve the 3 different dome issues that will present themselves.
http://www.pbs.org/wgbh/buildingbig/dome/challenge/index.html

 

Complete the Following cross word puzzle based on the 4 challenges in the exercises above.
 

Complete the puzzle.
 

Down
 
1. an effective ancient tunnel digging technique where the tools are water and______.
2. This is used in under water or soft ground tunnel digging to prevent cave ins.
3. a brace that transmits a force from a roof or wall to another supporting structure or the ground
4. TBM's or tunnel boring machines work best when tunneling through which material?
  Across
 
2. This creature is often the subject of controversy when a major dam is being considered.
4. The type of roof found at the skydome.
5. A cheap,but heavy material used in different types of structures.
6. One of the biggest reasons dams are created.
7. The weight of the dome is distributed evenly throughout the series of triangles in this kind of dome structure.
8. A light, waterproof material for covering a steel framed roof , but very expensive.
9. A common, but powerful natural force that skyscrapers have to deal with .
10. Some of the strongest and stiffest structures in existence today.
11. Large buildings heavy buildings sometimes develop this type of problem.

 

Structure Glossary: http://www.pbs.org/wgbh/buildingbig/glossary.html#reincon

 

Structures

Bridging the Gap
A few facts about New York's Verrazano-Narrows Bridge, the longest suspension bridge in the world until 1998:
  • All the wire in the main suspension cables laid end to end would cover more than 143,000 miles. That's more than halfway to the moon or almost six times around the earth.
  • It takes 36,725 gallons of paint to coat the bridge.
  • The cable anchorage blocks on either end of the bridge weigh 400,000 tons each.

 

 
Fun & Learning About Bridges
http://www.bridgesite.com/funand.htm