Earthquake Proof Housing8th grade

OverviewStudents will learn what concepts earthquake engineers suggest when designing a structure that is safe in an earthquake. They will then apply those concepts in designing and testing their own earthquake proof model.

Enduring Understanding: Technology can help man adapt to his changing environment

Overarching Question: Can structures be designed to be earthquake-proof?

Supporting Questions:1. What do engineers know about designing buildings to make them

earthquake-proof?2. What would an earthquake proof structure look like?

Science StandardsEarth and Space SciencesBenchmark B, Indicator 9: Describe the interior structure of Earth and Earth’s crust as divided into tectonic plates ride on top of the slow moving currents of magma in the mantle.Benchmark B, Indicator 10: Describe evidence of changes on Earth's surface in terms of slow processes and rapid processes Benchmark B, Indicator 11: Use models to analyze the size and shape of Earth, its surface and its interior (e.g., globes, topographic maps, satellite images).

Science and TechnologyBenchmark A, Indicator 1: Explain how technology from different areas has improved human lives Benchmark A, Indicator 2: Investigate how technology and inventions change to meet people's needs and wants Benchmark B, Indicator 3: Describe, illustrate, and evaluate the design process used to solve a problem

Technology StandardsNature of TechnologyBenchmark B, Indicator 1: Classify material by property

DesignBenchmark A, Indicator 1: Apply the design process to purposefully solve a

problem

Benchmark A, Indicator 2: Generate solutions for solving a problem using the design process, using information collected about everyday technological problems

Benchmark A, Indicator 3: Make sketches and paper models to visualize possible solutions to a technological problem.

Benchmark B, Indicator 1: Describe how models are used to communicate and test design ideas and processes

Benchmark B, Indicator 2: Describe the structural needs to be met when designing an object

Benchmark B, Indicator 3: Identify different types of engineersBenchmark C, Indicator 2: Apply the process of experimentation to solve a technological problem

Materials and Resources*Shake table (see Attachment A: Shake Table)Bowls for mixing "cement"Drawing paperEarthquake Proof Structure RubricFood materials (pretzels, graham crackers, marshmallows, licorice sticks, uncooked lasagna, spaghetti, etc.)Information sheets on earthquake engineering conceptsNewspaper for table coveringPopsicle sticks (for reinforcement only)StarchWater

Savage Earth Websitehttp://www.thirteen.org/savageearth/index.html

US Geological Survey Education Resources – Earthquakeshttp://education.usgs.gov/common/secondary.htm#earthquakes

Web sites on Earthquake engineeringhttp://school.discovery.com/lessonplans/programs/earthquakeproof/

US Geological Survey: Earthquake Science Explained: Article 9: How do we make buildings and roads safe?http://mitigation.eeri.org/files/USGS.eq.science.expl.pdf

Latest Earthquakes in the World, last 7 dayshttp://earthquake.usgs.gov/eqcenter/recenteqsww/

Photos of earthquake damage to buildingshttp://web.ics.purdue.edu/~braile/edumod/eqphotos/eqphotos1.htm

Build a simple model of slip-stick movement at a fault linehttp://tremor.nmt.edu/activities/stick-slip/home.htm

Procedure:Pre-Assessment1. Ask students to discuss:

What an earthquake is What causes an earthquake Where earthquakes frequently occur in the world What type of damage can a building withstand during an earthquake Why earthquake proof housing is important.

Scoring the pre-assessmentFrom the students’ answers, the teacher should have an idea of what students know about earthquakes and what damage they can cause. It also will pique their interest in the project.

Post-AssessmentUse the rubric (Attachment B) to assess students on their understanding of earthquake engineering concepts, the design and construction of their project, and their presentation.

ProceduresDay 11. Do the pre-assessment with the students.

2. Discuss earthquakes and their causes. Important concepts about earthquakes the students need to understand in order to design earthquake-resistant structures would include:

a.

3. Observe and discuss earthquake engineering ideas that will help reduce the effect of earthquakes on structures.

4. Make a detailed drawing of your planned house on graph paper. Include both a side and a front drawing, materials used, and include three ideas you learned about earthquake engineering to make your house earthquake proof.

5. Construct your house using food material (uncooked spaghetti, pretzels, uncooked lasagna, graham crackers, etc.) and a starch/water "concrete".

6. Make a presentation of your house to the class. Explain the materials and ideas you used in building your house.

7. Test your house on the shake table.

8. Complete the evaluation sheet on your project. See Earthquake Proof House Evaluation Form (Attachment B).

Attachment A: Shake Table for the Earthquake Proof Building Project

1. Shaker Board 1

Materials: Marbles coffee can lid piece of wood (or wooden platform) box lid (about 1/2" depth)

Procedure:1. Staple plastic lid to wooden block2. Put marbles under the lid. Experiment with varying amounts and sizes.3. Place marbles, plastic lid, block of wood in card board box lid to contain

amount of movement.4. Place structures on the wooden block and simulate an earthquake.5. First do back and forth motion to imitate P waves (more accurate if very

rapid). Next do vertical or side to side motions to imitate S waves (more accurate if very rapid). Surface waves with a gentle, rolling motion-arrive later.

Attachment B: Earthquake Proof HouseEvaluation Form

Name:

Class period:

Teacher and Student: Rate the following according to the following scale:

1 = poor, 2 = good, 3 = excellent

Student Teacher1. Plan contained 3 ideas involving

earthquake engineering _____ _____

2. Plan was original _____ _____

3. Drawing was neat and accurate _____ _____

4. House was neatly constructed _____ _____

5. House had a roof and door _____ _____

6. House was made of appropriate materials _____ _____

7. House was built within size constraints _____ _____(5" wide X 8" long)

8. House survived earthquake simulation _____ _____on the shake table

9. Presentation was well-organized _____ _____and clearly understood

10.Presenter indicated understanding _____ _____of earthquake engineering concepts

11.Presenter shared presentation time _____ _____

12.Group member solved problems _____ _____in an appropriate manner

13.Group member shared responsibilities _____ _____and contributed equally to the project

Total: _____ _____

Evaluation (p. 2)

1. The part of this project I liked was:

2. The part of the project I was unhappy with was:

3. I learned these three things from doing this project (facts on earthquakes, methods of building, communication skills, etc.)

4. If I were to redesign my house, I would:

5. If I were to change anything about this project, I would:

6. If I were to tell my friends about this project, I would say:

Earthquakes and Seismograph StationsIn Ohio

Earthquake Proof Architecture

1. The building should be anchored to the base rock foundation

2. The walls and joints should be reinforced

Base rock

Foundation of house

anchors

This house was not securely fastened to its foundation.

3. There should be metal wraps around columns

4. Short

distances between wall supports

5. Buildings and materials should be light

wall

support

These columns were not designed to correctly support the weight of the road above

6. Buildings should be simple, symmetric

7. Stiffness is important in construction. Walls and joints need to be reinforced.

Cross bracing

Reinforced corners

8. Shear walls, made of reinforced concrete (concrete with steel rods or bars embedded in it), help strengthen the structure and help resist rocking forces. Shear walls in the center of a building, often around an elevator shaft or stairwell, form what is called a shear core.

Builders also protect medium-sized buildings with devices that act like shock absorbers between the building and its foundation. These devices, called base isolators, are usually bearings made of alternate layers of steel and an elastic material, such as synthetic rubber.

Building skeleton

Shear wall with reinforcing rods

Base of building

steel

rubber

1. Each floor should be the same in stiffness. The first floor should not be “soft”, that is, open with lots of windows or for a first floor car garage.

The Science of Earthquakes

From the U. S. Geologic Survey site: http://earthquake.usgs.gov/learning/kids/eqscience.php

(originally written by Lisa Wald for "The Green Frog News") What is an earthquake?An earthquake is what happens when two blocks of the earth suddenly slip past one another.  The surface where they slip is called the fault or fault plane.  The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter. (figure 1)Sometimes an earthquake has foreshocks.  These are smaller earthquakes that happen in the same place as the larger earthquake that follows.  Scientists can’t tell that an earthquake is a foreshock until the larger earthquake happens.  The largest, main earthquake is called the mainshock. Mainshocks always have aftershocks that follow.  These are smaller earthquakes that occur afterwards in the same place as the mainshock.  Depending on the size of the mainshock, aftershocks can continue for weeks, months, and even years after the mainshock!

What causes earthquakes and where do they happen?The earth has four major layers: the inner core, outer core, mantle and crust.  (figure 2) The crust and the top of the mantle make up a thin skin on the surface of our planet.  But this skin is not all in one piece – it is made up of many pieces like a puzzle covering the surface of the

earth. (figure 3)  Not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other.  We call these puzzle pieces tectonic plates, and the edges of the plates are called the plate boundaries.  The plate boundaries are made up of many faults, and most of the earthquakes around the world occur on these faults.  Since the edges of the plates are rough, they get stuck while the rest of the

plate keeps moving.  Finally, when the plate has moved far enough, the edges unstick on one of the faults and there is an earthquake.

Why does the earth shake when there is an earthquake?While the edges of faults are stuck together, and the rest of the block is moving, the energy that would normally cause the blocks to slide past one another is being stored up.  When the force of the moving blocks finally overcomes the friction of the jagged edges of the fault and it unsticks, all that stored up energy is released.  The energy radiates outward from the fault in all directions in the form of seismic waves like ripples on a pond.  The seismic waves shake the earth as they move through it, and when the waves reach the earth’s surface, they shake the ground and anything on it, like our houses and us! (see P&S Wave inset)

How are earthquakes recorded?Earthquakes are recorded by instruments called seismographs. The recording they make is called a seismogram. (figure 4)  The seismograph has a base that sets firmly in the ground, and a heavy weight that hangs free.  When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the

hanging weight does not.  Instead the spring or string that it is hanging from absorbs all the movement.  The difference in position between the shaking part of the seismograph and the motionless part is what is recorded.

How do scientists measure the size of earthquakes?

The size of an earthquake depends on the size of the fault and the amount of slip on the fault, but that’s not something scientists can simply measure with a measuring tape since faults are many kilometers deep

beneath the earth’s surface.  So how do they measure an earthquake?  They use the seismogram recordings made on the seismographs at the surface of the earth to determine how large the earthquake was (figure 5).  A short wiggly line that doesn’t wiggle very much means a small earthquake, and a long wiggly line that wiggles a lot means a large earthquake.  The length of the wiggle depends on the size of the fault, and the size of the wiggle depends on the amount of slip. The size of the earthquake is called its magnitude.  There is one magnitude for each earthquake.  Scientists also talk about the intensity of shaking from an earthquake, and this varies depending on where you are during the earthquake.

How can scientists tell where the earthquake happened?Seismograms come in handy for locating earthquakes too, and being able to see the P wave and the S wave is important.  You learned how P & S waves each shake the ground in different ways as they travel through it.  P waves are also faster than S waves, and this fact is what allows us to tell where an earthquake was.  To understand how this works, lets compare P and S waves to lightning and thunder.  Light travels faster than sound, so during a thunderstorm you will first see the lightning and then you will hear the thunder.  If you are close to the lightning, the thunder will boom right after the lightning, but if you are far away from the lightning, you can count several seconds before you hear the thunder.  The further you are from the storm, the longer it will take between the lightning and the thunder.P waves are like the lightning, and S waves are like the thunder.  The P waves travel faster and shake the ground where you are first. Then the

S waves follow and shake the ground also.  If you are close to the earthquake, the P and S wave will come one right after the other, but if you are far away, there will be more time between the two.  By looking at the amount of time between the P and S wave

on a seismogram recorded on a seismograph, scientists can tell how far away the earthquake was from that location.  However, they can’t tell in what direction from the seismograph the earthquake was, only how far away it was.   If they draw a circle on a map around the station where the radius of the circle is the determined distance to the earthquake, they know the earthquake lies somewhere on the circle.  But where?Scientists then use a method called triangulation to determine exactly where the earthquake was (figure 6).  It is called triangulation because a triangle has three sides, and it takes three seismographs to locate an earthquake.  If you draw a circle on a map around three different seismographs where the radius of each is the distance from that station to the earthquake, the intersection of those three circles is the epicenter!

Can scientists predict earthquakes?No, and it is unlikely they will ever be able to predict them.  Scientists have tried many different ways of predicting earthquakes, but none have been successful.  On any particular fault, scientists know there will be another earthquake sometime in the future, but they have no way of telling when it will happen.

Building Structure ExerciseDesigning Structures To Perform Well During an EarthquakeDid you ever notice that after an earthquake some structures have a lot of damage while others have little? There are different factors that affect how structures perform during an earthquake.

Important Design Considerations

When you design buildings, there are a number of factors you need to consider:

Shape of the building: different shaped buildings behave differently. Geometric shapes such as a square or rectangle usually perform better than buildings in the shape of an L, T, U, H, +, O, or a combination of these.

Various materials used to construct the building(s) can be used (alone or in combination): steel, concrete, wood, brick. Concrete is the most widely used construction material in the world. It is comprised of sand, gravel, and crushed stone, held together with cement. Each material behaves differently. Ductile materials perform better than brittle ones.

Examples of ductile materials include steel and aluminum.

Examples of brittle materials include brick, stone and unstrengthened concrete.

Height of the building different heights shake at different frequencies.

Soil beneath the building.

Regional topography.

Magnitude and duration of the earthquake.

Direction and frequency of shaking.

The number of earthquakes the building has previously had and the kinds of damage suffered, if any.

Intended function of the building (e.g. hospital, fire station, office building).

Proximity to other buildings.

What Can You Learn by Constructing Buildings?

The effect of the different variables on building performance during a simulated earthquake.

Ways to strengthen the buildings

What physical forces are at work during an earthquake.

Making Wood Frame Structures

Materials:

Popsicle sticks, clay, styrofoam piece, and a shake table for testingProcedure:

Construct one or two story frame buildings using popsicle sticks with clay for jointing. Let the building sit until the clay is cool and stiff. If desired, use the styrofoam piece to make a foundation for the building. Cut the styrofoam the same size as the external perimeter of the house with a cutout for a basement. Try setting the building on the styrofoam or fastening the building to the styrofoam with clips, tacks, or an adhesive. Test your model structure, like engineers often do, on a shake table or seismic simulation equipment to see how it performs during a simulated earthquake.

Strengthening Your Building: Try cross or diagonal bracing to further stabilize your building. Cross-bracing means you put in vertical "X' shaped braces between the popsicle stick walls. Try different materials for your crossbraces and see which works best: popsicle sticks, kite string, straws.

Simulating Masonry (Brick, Stone or Adobe Structures)

Materials:

Sugar cubes (1 box per structure), peanut butter, frosting or doublesided tape, piece of Styrofoam, cardboard, and aluminum window screen scraps

Procedure: Construct one and two story rectangle and L-shaped buildings on Styrofoam bases, using sugar cubes for bricks, cardboard for the floor and roof, peanut butter, and frosting or double-sided tape for mortar. Again, try setting the building on the Styrofoam or somehow connecting it to the Styrofoam. Then test your model structures on shake tables to see how they perform during a simulated earthquake. Which are more stable, one

or two story structures? How did the right angle in the Lshaped building effect the stability of the structure?

Strengthening Your Building: Carefully cut pieces of screen smaller than the size of each of the walls. Spread a very thin layer of peanut butter or frosting on each screen and carefully attach the screen to each of the inside walls of the first story. Reinforce the corners with extra peanut butter from inside. This is a model of a one story reinforced masonry structure. Try different sized screen fine and widely spaced. How do the buildings respond now when shaken?

Steel Frame Structures

Materials:

Pipe cleaners, t-pins, Styrofoam piece, cardboard/ paper pieces (optional) Procedure:

Construct a model of a modern high-rise steel framed city building using pipe cleaners. Bend the end of one pipe cleaner around the end of the other. Do not twist the ends together. Attach each model to a Styrofoam base with T pins. Test it on a shake table to see how it performs during a simulated earthquake.

Adding the Walls: A steel frame structure looks sort of like a jungle gym. However, the finished building has walls and windows. Make cardboard or paper walls and add them to your structure. How does it perform on the shake table? Try other materials for the walls and cross-bracing to strengthen the structure.

Additional Resources:

Levy, M., & Salvadori, M. (1992). Why buildings fall down: How structures fail. NY: W. W. Norton.

Salvadori, M. (1990). The art of construction: Projects and principles for beginning engineers and architects. Chicago: Chicago Review Press.

Steinbrugge, K. V. (1982). Earthquakes volcanoes, and tsunamis: An anatomy of hazards. NY: Skandia America Group.

Models developed by: Gary Dargush, Kathy Donnatin, Donna Lico and Tori Zobel.

 ©2006 the Research Foundation of the State of New York. All rights reserved.

Stick-Slip MovementRationaleStudents will operate a model to observe the type of motion that occurs at a fault during an earthquake and explore the effects of several variables.Focus QuestionsHow much energy will a fault store before it fails?

1) Is this quantity constant for all faults?

Objectives

Students will:

1. Model the frictional forces involved in the movements of a fault.

2. Measure movement, calculate averages, and plot this information on a graph.

3. Explore the variables of fault strength vs. energy stored.

MaterialsFor each small group

1 copy of Master Stick-Slip Data Sheet

4 sandpaper sheets, 60, 120, and 400 grit

Scissors

Strapping tape

1-lb weight

8 thumbtacks

A box of rubber bands

2 large paper clips

Yardstick or meter stick

2 m of string

Large dowel

Marking pen

Scales

Pine board, approx. 2.5cm x 30cm x 1.8m

Several books to support one end of the board

Protractor for measuring angles

 ProcedureTeacher PreparationTo assure success, construct the model ahead of time and rehearse the activity. Then arrange materials for student models in a convenient place.

Introduction

Elicit a definition of fault from the class, supplementing students’ information as necessary until the essential elements have been covered.

Explain to students that when an earthquake occurs and movement begins on a fault plane, the movement will not proceed smoothly away from the focus. Any change in the amount of friction along the fault will cause the fault movement to be irregular. This includes changes along the length of the fault and with depth, changes in rock type and strength along the fault, and natural barriers to movement, such as changes in the direction of the fault or roughness over the surface of the fault plane.

Rupture along a fault typically occurs by fits and starts, in a type of sporadic motion that geologists call stick-slip. As energy builds up, the rock on either side of the fault will store the energy until its force exceeds the strength of the fault. When the residual strength of the fault is exceeded, an earthquake will occur. Movement of the fault will continue until the failure reaches an area where the strength of the rock is great enough to prevent further rupture. In this manner, some of the energy stored in the rock, but not all of it, will be released by frictional heating on the fault, the crushing of rock, and the propagation of earthquake waves.

Lesson Development

1. Divide the class into working groups of at least four students each. Distribute one copy of Master 2.1a, Stick-Slip Data Sheet, to each group. Tell students that the are going to model a process, record data for each trial, and then vary the process, changing only one variable at a time.

2. Allow groups to assemble their materials, then give these directions:

a. Fold each piece of 120-grit sandpaper in half lengthwise and cut, to produce eight strips of sandpaper, each 11.5 cm x 28 cm (4.5 in. x 11 in.) in size.

b. Wrap one of the strips around the box and secure it around the sides (not the top and bottom) with two rubber bands. (See diagram.) Weigh and record box mass.

c. Tape the seven remaining strips of 120-grit sandpaper into one long strip. (Be sure to use tape only on the back of the sandpaper.) Now attach the sandpaper lengthwise down the center of the pine board, using two thumbtacks at each end and being sure the sandpaper is drawn tight.

d. Attach one paper clip to one of the rubber bands around the box.

e. Tie one end of the string onto another paper clip and place a mark on the string about 1 cm from the clip. Use one rubber band to join the paper clip on the box with the paper clip on the string. Tie the free end of the string around the dowel or paper towel roll.

f. Tape the meter stick onto the sandpaper strip on the board.

g. Position the box at one end of the board so it is centered on the sandpaper. Use books to raise the other end of the board approximately 10 cm (4 in.). Measure and record the height.

h. Gently roll the string onto the dowel until the string lifts off the paper and becomes taut. Note the location of the mark on the string relative to the meter stick. Take care to keep the dowel in the same position during rolling and measurement.

i. Continue to roll the string onto the dowel until the box moves. The box should move with a quick, jumping motion. Record the new location of the mark on the string (the distance the box moved) on the data table. Continue rolling up the string and recording jump distance until the box hits the meter stick. The meter stick can be pulled upwards to allow the box to continue to be pulled.

j. Subtract the beginning measurement from the ending measurement or add up the jump measurements to find out how far the box moved. Divide by the number of jumps to calculate an average jump distance.

2. Instruct other students in the same group to change one variable, repeat the procedure, and average the distance of the jumps. Students may vary the model by adding one or more rubber bands, adding more books to change the angle of the board, substituting the brick for the box, or using sandpaper of a different grit. If time allows, give every student a chance to operate the model with each of the variations.

3. Ask students to complete their data sheets.

Conclusion

Ask the class:

What might the different variables represent in terms of earthquakes and landscape conditions? (Number of rubber bands – different amounts of energy released; angle of the board – steepness of the

fault; sandpaper grit size – differences in the amount of force required for a fault to move – the amount of friction.) Emphasize that different faults can store different amounts of energy before they fail. Some faults have the potential for generating larger earthquakes than others.

Do the rubber band and string go totally slack after each movement? (No.) What does this tell you about the release of stored energy on a fault when an earthquake occurs? (No earthquake ver releases all the energy stored in the Earth at a particular point. It is because some stored energy always remains that one quake may have numerous foreshocks and aftershocks, and earthquakes recur frequently in some active areas.)

 

Created By Dave Love, Chris Durand and John Van Der Kamp

last modified: 9 January, 2007