Which Building Design Withstands Earthquake Pressures Best?
Researched by Jordan P. 1999-2000	PURPOSE HYPOTHESIS  EXPERIMENT DESIGN  MATERIALS  PROCEDURES  RESULTS  CONCLUSION  RESEARCH REPORT  BIBLIOGRAPHY ABOUT THE AUTHOR

The objective of this experiment was to determine which type of structural design and building would better withstand the effects of differing levels of pressure, strain, force and magnitude resulting from an earthquake. It will also determine how well they do in differing seismic waves.

I became interested in this idea while in 4th grade when I learned that the Seattle space needle was probably the safest place in Seattle during an earthquake because of its flexibility. I followed it up with much passion, interest and research on earthquakes and especially on building construction in earthquake zones. I also have family in California at the present time and the National Geological Society predicts that a tremendous earthquake will strike California in the next 30 years.  I also learned that the most damage done in an earthquake is due to faulty building design and engineering. So by this experiment it will help them determine which type of building would benefit them during an earthquake.

The information gained from this experiment will benefit geologists, engineers, businesses, and other groups determine what type of building structure will help prevent the most damage and be cost efficient as well as appropriate for their needs.

I believe that the structure design that has a base isolator will withstand the most pressure until extremely high levels of strain from the earthquake.  The other construction include a normal building, a building that contains a diagonal cross-bracing and with an interior center or shear core that is made out of toothpicks, and a building that is held up by stilts all will collapse at earlier levels of force. I will be using the same materials to construct them.

I base my hypothesis on the fact that in "earthquake games", by Mario Salvadori and Matthys Levy, it quotes that  " inertia will prevent the building from moving and the building will not feel the earthquake". Meaning that a building isolated from the ground won’t feel the earthquake inertia.  I believe that this will sustain my hypothesis.  Inertia is like mass and acts like mass.

The constants in this study were:
* The levels of velocity, pressure, and magnitude emitted from the earthquake simulated by the conductor I produced and the point I pulled it back which I used a ruler to help me record I. 
* Three different seismic waves that were produced by the shaker table that each building was subject to. 
* The waves used: shear waves also called (secondary waves), love waves and Rayleigh waves. 
* Where the building was located on the shaker table. 
* The amount of buildings for each design. 
* The material used to build them. 

The manipulated variable was the different structural and engineering designs being tested and the way they were built. Another manipulated variable included the different types of seismic waves being produced by the earthquake simulation and the increase of pressure until the building design crumbles or collapses. This was done so that it enabled me to see the level of pressure that it was at in order to record and determine at how much pressure made it collapse. 

The responding variable was distances the springs of the model earthquake simulator were stretched to produce the force necessary to destroy the model building. 

To measure the responding variable I used a metric ruler to determine how far I stretched the springs on the shaker table to simulate the waves. 

QUANTITY	ITEM DESCRIPTION
1	4.445cm x 47.625cm Plywood Board
4	10.16 cm high spring
1	hammer
8	nails
2	30.48cmx7.62cm of base cove rubber
1	package of hard spaghetti
1	Ruler 12 inches
1	package clay

1. Buy all materials indicated and listed on the materials list. You may proceed to buy them a local hardware store where these items may be sold. To construct the shaker table you will have to find or order a scientific guide or a scientific catalog or guide. After purchased, take your plywood board and if it doesn’t meet these measurements, 1.75 inches, 4.445centimeters thick and 24 by 18.75 inches, 60.96 by 47.625 centimeters in length then prepare to cut to make it this exact size.  Then find two plywood pieces each four feet long.

2. Then take your four flexible springs 4inches, 10.16 centimeters in length and attach them by nailing them to the left and right corners of the board then take the board and place it in a safe place between two desks, chairs or tables so the bottom part hangs down.

3. Once all this is placed you must then buy wooden coffee sticks used to stir coffee these can be about 4 inches, 10.16 centimeters to about .5 of an inch or 1.27 centimeters. You will also need to buy base cover rubber at about 2 feet, 30.48 centimeters long. Cove rubber can be purchased at most local hardware store and stir sticks can be purchased at almost any craft warehouse.

4. Take you’re your rubber and cut it to make four sides each 2 inches, 5.08 centimeters tall and make them 4 inches, 10.16 centimeters long and make the roof 3 by 3 inches, 7.62 by 7.62 centimeters. This will act as your base isolator. 

5. Then take out the package of stir sticks their should be a thousand. 

6. You will begin constructing your first building. The building design will be a simple building with no interior fortifications preventing earthquake damage. It will not include exterior fortifications such as a base isolator reverting ground damage. Take your stir sticks and place them together to make an exterior wall that is not protected by anything else but framework. To hold the building together use play dough and in small quantities. Make sure the building is 6 inches, 15.24 centimeters in height and make the base 3 inches, 7.62 centimeters in length. If the framework does not meet these measurements prepare to cut them to make them the correct size.

7. Repeat step 7 two more times and do not do anything different.

8. Then create a building that is an exact replica of the last one but with but attach the rubber base this will act as the base isolator.

9. Repeat step 9 2 more times but use the same base isolator.

10. Make the next building as the same as the last one except add stilts to it of about 7 stir sticks each to every corner.

11. Repeat step 10 two more times.

12. Then you will begin the experiment. Make sure to place the buildings in a safe place.

13. The first trial will then begin. Place the first building on the bottom of the shaker or the part that is hanging down. Place the building there carefully.

14. The first wave you will be conducting will be love waves. Love waves travel and shake buildings by a side way motion. Take a ruler and have someone hold the ruler on the side of the shaker table. If no one is available then tape the ruler so the markings are visible to a chair or table that goes directly under the shaker table and place it on either side of the hanging part. Then make sure that the ruler is visible. Then pull the table back to the one-inch mark and let go. 

15. Record the results. If the building fell then record that it fell on the 1 inch line and record it in centimeters. If the building does not crumble then pull it back 1inch or 2.54 centimeters each time. Then record the measurement it collapsed at.

16. Repeat this step with one model of the building types each. Record the results.

17. The next wave replicated was Rayleigh wave. To replicate this you must do the exact same with the ruler as the last experiment but this time hold it up horizontally and tip one of the ends so the other end is higher. Then conduct it the exact same way. 

18. Record the results and do the experiment with one model of each structural design.

19. The next wave produced was shear. Take the ruler and make it horizontal place it on one side and pull down with equal force on both sides down to the 1 mark or the 2.54 centimeter mark and let up do the same as the previous trials and record the results.

20. Then do the same with one model from each group this should deplete the rest of your models. Remember to record the results for each of the tests.

21. Record all the data, place and organize it onto a graph on Microsoft excel.

The original purpose of this experiment was to determine which type of building design would withstand earthquake pressures best. These buildings included a building without any earthquake defenses, a building with a base the buildings did opposed to differing types of seismic waves which included shear waves, Love waves and Rayleigh waves.

The results of the experiment showed that the building that withstood the most earthquake pressure on average was the building with interior fortifications allowing it to maintain its shape and position. The building held up by stilts also performed the best out of the buildings and was as effective as the building with interior fortifications.  The building that did the worst was the building with no earthquake defenses whatsoever and without anything to isolate the seismic waves. It is difficult to conclude which building design was best overall because certain buildings had varying results with different seismic waves.

See the graph below.
 

My hypothesis was that the structure designed with a base isolator would withstand the most pressure. 

The results indicate that this hypothesis should be rejected. The building with the base isolator did not perform as well as the building with interior fortifications and the building held up by stilts when subjected to Rayleigh waves. It did not do as well as the building with stilts and it performed the same as the building with interior fortifications when subjected to shear waves.

Because of the results of this experiment, I wonder if buildings that are in a certain spot on my model earthquake simulator would change the way the seismic wave affected it. I also wonder if a building combination, such as buildings with stilts as well as interior fortifications, would do better than buildings without a combined design. If I changed the topography (even if I placed a tank of different soils, landscapes, topography and water levels on the shaker table) would it affect the way the seismic waves were created and worked and how much pressure the building could withstand. I also wonder if I put a group of different building s together (like in a mall or condominium), would they last longer than a similar number of lone buildings. I also wonder if I made the buildings out of the same material used in true buildings would theylast longer.

If I were to conduct this project again I would have added more structural designs and buildings that would have included buildings with wings on them, tall buildings with a ground-level lobby, and sky scrappers. I would also use a better model earthquake simulator perhaps with a vibrating machine that would make the shaker table more powerful. I would use a scale truer to that of the Richter scale and use my own observations as the Mercalli scale. I would have also done more trials. 
 
 

RESEARCH REPORT INTRODUCTION Natural disasters are some of the worst, most horrible, and intriguing events that take place in history. And one of these is the earthquake. An amazing natural phenomenon. Millions strike each year most hardly even felt. But there are the occasional big ones that strike at the heart of the human populace sometimes in a large metropolitan area, like San Francisco. This is when these natural phenomenon turn deadly. These large quakes, besides killing lives and causing mass destruction, allow scientists a rare window into the earth and its geology. In an attempt to safe guard the human populace, engineers have developed many ways to "earthquake proof" our buildings. Plates and plate-tectonics The earth is divided into layers like that of an apple. It has a crust or hard outer layer. It has a mantle or large molten layer of the earth with molten rock and lava. It has a core and an outer core both of boiling hot metal. On top of this sea of magma is floating the crust. It is the only habitable place on earth for humans. The crust is 35 kilometers and 60 miles thick on average on the continental crust and 5 kilometers 3 miles thick in the ocean basins. The continental crust is made of granite and the ocean basins are made of basalt. Along with the upper mantle it forms the lithosphere. This is divided into 7 large plates that are constantly moving on this sea of magma. Their pace is slow but constant and over time they will collide into each other in what is called plate tectonics. Plate tectonics occurs when two plates slide past each other grinding past one another or pushing into one another. Some times the plates will subduct or the larger plate will slide into the magma and the lighter plate slides over the larger one. Or, over a period of time the plates will slide past each other building up pressure and just one slippage could cause a huge amount of energy to be released culminating in major destruction. The plate tectonics also create mountain ranges.  Faults These places where the ruptures occur are called faults. These deep ruptures occur due to plate tectonics. The faults can move up, down, sideways or horizontal past each other. Faults are usually located underground but some like the San Andreas Fault are above ground.  There are 3 types of fault movements. They are strike and slip faults which occur due to a deep rupture and the plates slide horizontally past each other. Normal faults occur when the upper rock slides down. Reverse faults occur when the rocks are tightly compressed and one is forced upward and the other downward. When faulting occurs it releases immense amounts of energy up to 10,00 atomic bombs when the fault slippage is great. The area where the rupture occurred is called the focus the are right above it on the surface of the ground is called the epicenter.  Most earthquakes occur on the alpide belt or the circum pacific belt. The alpide belt runs from Portugal to Australia and the circum pacific belt runs around the pacific. The fault releases the energy, as seismic waves, which travel outward from the epicenter, like ripples on a pond.  Seismic Waves These waves have helped scientists who study earthquakes, called seismologists, who study the geology of the inner earth by time lapses in seismic wave arrivals. These waves also cause much damage, but the farther from the focus they are the weaker they occur. Stations have been built world wide to follow the movements of the seismic waves. It takes only three stations to find the epicenter of an earthquake using seismic waves. Each station measures the time each seismic wave type came in and then using this data they can draw a line on a map from each station where these lines intersect is the epicenter or focus. These also help seismologists determine what rocks lie beneath the Earth’s surface because certain waves travel faster in certain rocks and so they measure time elapses to determine this. Seismic waves that occur under the sea create tsunamis or tidal waves these cause much damage and swamp coastal villages and towns but boats on the sea can’t feel them because it takes the waves a considerable amount of time to get momentum. There are two types of waves they are body waves and surface waves. Body waves are quicker than surface waves and cause more damage they also travel underground. Surface waves are slower, weaker and travel on the surface of the ground.  Body waves include compression waves and shear waves. Compression waves are also called primary waves because they are the fastest wave type traveling at 7-10 MPS (miles per second) and they are able to go through gases, liquids and solids because they are sound waves. Primary waves shake buildings by compressing and expanding, ripping the buildings apart. Shear waves also called secondary waves travel about half as fast as primary waves. They are confined to travel through solids. They shake buildings instead of pulling them apart and move rock from side to side. Surface waves include Love waves and Rayleigh waves named after two 19th century English scientists. Rayleigh waves are the third fastest waves and shake the ground like waves on the ocean. Love waves are the slowest and least dangerous they shake the rocks from side to side. Two scales exist for rating earthquakes they are the Richter scale named after its founder and the Mercalli scale, which was also named after a person. The Richter scale rates an earthquake on its strength and the Mercalli rater it on the effect it has on the populace and the buildings.  Building Designs Building designs are very important to understand to try to "fool proof" your city or populace in case of an earthquake. People dwell, eat, sleep, and conduct there lives from within shelters that usually come as buildings. When an earthquake occurs it can devastate lives. That is why it is vital to protect buildings and work towards a building design that is almost earthquake "proof". Two extremely important principles exist when constructing a building designed to be earthquake "proof". They are the flexibility of the buildings and the ductility of them. The building must not be too rigid or it will collapse during an earthquake. It must also be durable enough to cope with earthquake pressures. That is why concrete, which is brittle, is embedded with steel bars. Buildings are also built using many different techniques. These are cross-bracing's or steel bars built to hold up walls, base isolators built underground to isolate the building from the earthquake pressures, shear walls or walls embedded with steel bars, and a shear core or a central concrete pillar that surrounds an elevator or stairwell. Skyscrapers are built with deep foundations and flexible joints. Summary Earthquakes are natural phenomenon. They are also deadly killers and can occur any time anywhere and cause mass destruction and deaths. The only way to prevent mass damage until we develop a way to detect them before they happen is to begin to prepare our buildings and vital public services and our lives for them. BIBLIOGRAPHY  "Earth", exploring your world. 1989  "Earthquake loads", The new encyclopedia Britannica. 1993  "Earthquakes" Encarta encyclopedia 2000 Isachson, Y.W., Landing, E., Lauber, J.M., "What are seismic waves?" Avail3faqs/seiswave.html, December 8,1999 Hays, Walter H., "Nature on rampage", UNESCO Courier.  Pp. 1, October, 1997 Lambert, David Field Guide to Geology New York, New York: Facts on file, 1988 Page Robert A. "Earthquake", World Book Encyclopedia.1991. Vol. 6. Pp. 33-34 Pakiser, Louis and Shedlock, Kaye M. "Where do earthquakes usually occur?" Salvadori, Mario and Levy, Matthys Earthquake Games New York, New York: Simon and Schuster children's publishing, 1997 Varley, Carol and Miles, Lisa The Usborne Geography Encyclopedia America: Usborne Publishing, 1992

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