BAD VIBRATIONS

Key Question In earthquake prone areas what features do you think are incorporated in the design of houses, buildings, and infrastructure (subways, sewer systems, water pipes, electrical pipes etc.). Discuss this with your group and write your answer in your notebook.

True or False When an earthquake strikes, more people are killed by things such as falling debris than by the earthquake itself. True

The reason that so many structures are damaged during an earthquake is due to the fact that typical buildings are not designed to take the type of stresses that earthquake waves produce.

For the most part, standard buildings-especially skyscrapers-are designed to withstand the forces of gravity and wind shear.

When the earth starts to shake, however, the vibrations traveling through the ground are often amplified by the building structure itself. These hefty buildings may apply pressure to the ground, causing a strain so great that the building may eventually collapse.

In an attempt to minimize earthquake damage, many buildings in “high risk” areas have been built to be “earthquake resistant.”

In this activity, you are to observe how different types of structures stand up to vibrational forces.

Video http://www.youtube.com/watch?v=HB2jgJJG2is&feature=related http://www.youtube.com/watch?v=lVsBF_YJXZQ http://www.bing.com/videos/search?q=video+of+poor+earthquake+construction&view=detail&mid=95042B3B36C714407C9195042B3B36C714407C91&first=81

What to Do! You and your group are to construct a building using pasta and marshmallows. Your building must be at least 20 cm tall. Each structure will be placed on a “shaker table” The winning structure will be the structure that withstands the most amount of shakes without tipping or breaking.

If there is a tie… The taller structure will win!

First… In your notebook, design your earthquake proof structure. Explain the special feature that your structure has that will help it survive an earthquake. How will your special feature “save” your structure from an earthquake? Be prepared to discuss your groups design. Use the worksheet to list example from each group

Class Discussion List an item from each group that makes it earthquake proof. Use the earthquake design sheet.

After your teacher has approved your design, you may begin.

Observe the winning structures In your groups, list and discuss the special features of the winning structures. How did these features help the structure to withstand an earthquake?

Additional Information After every earthquake, engineers rush in to study why buildings crack and crumble and what can be done to make structures safer.

At the University of California at San Diego, scientists are recreating the force of the 1994 Northridge, California earthquake that killed dozens and caused considerable damage to wood-framed buildings and $2.5 billion of damage overall.

What they learn will help them improve building codes.

The reason some earthquakes are so deadly is a matter of magnitude and depth. An earthquake which occurs in a underdeveloped country will do more damage than an earthquake that occurs in a developed nation The construction of the buildings is what proved to be the difference.

Most buildings in the underdeveloped country are constructed of unreinforced masonry which crumbled under the strength of the quake, causing increased injury and even death.

Future Quakes Experts predict that a large earthquake can occur in Seattle, Washington resulting in great devastation.

Most buildings in the Seattle area are not earthquake proof. Old homes are often made of brick. Many of the brick structures are not reinforced with steel bars. In addition, older buildings are not attached to their foundations.

Buildings need… Reinforced structures Attachment to a foundation

Ancient Cultures People in ancient cultures who lived in earthquake areas built earthquake-resistant buildings.

Buddhist Pagoda in Japan Central shaft is sunk into the ground Flexible joints attach the roof sections to the central shaft The shaft sways during an earthquake, but the roof doesn't fall

Chinese architects Designed tent like structures Building has a sloping, tiled roof Central wooden beam supports the length of the roof Each end of the beam has vertical shafts driven deep into rock Lightweight bamboo walls hang from the roof almost like curtains

The walls absorb energy by swaying

American Southwest and Central America Adobe buildings Adobe walls are made of clay bricks with a crisscross network of twigs Gives flexibility to each wall The walls absorb the energy of the earthquake waves

Post Questions What did you learn from this activity? How would you change your design?

Hagia Sophia Enrichment The Byzantine Church of Hagia Sophia stands atop the first hill of Constantinople at the tip of the historic peninsula, surrounded by the waters of the Sea of Marmara, the Bosphorus and the Golden Horn on three sides. Research the Hagia Sophia. What did the early architects do to build a structure that has lasted and withstood earthquakes?