Introduction Structural Engineering - Wikispacessciencelearningcommunity.wikispaces.com/file/view/... · · 2012-01-21Introduction – Structural Engineering ... the many factors

Introduction – Structural Engineering

Structural engineering is a field of engineering dealing with the

analysis and design of structures that support or resist loads.

Structural engineers are most often involved in designing buildings

and other large structures such as bridges. When structural

engineers develop their plans, they must take into account safety,

performance, as well as the cost of materials used.

In this unit, we have included activities that will simulate what

structural engineers do on a small scale. In almost all of the

activities, the students must not only consider how sound the

structure is but also how many resources are needed for building

the structure. Students will build earthquake-proof structures,

bridges out of straws, and domes out of gumdrops. The students

will test various parameters of each structure they build, such as

how fast a marble can roll through their foam roller coaster and

how long they can make their Popsicle stick structure last through

an earthquake. These activities will help the students understand

the many factors structural engineers must analyze and evaluate in

order to build a successful structure.

Grade Level:

All

Activity – Marble Roller Coaster

Introduction: In this activity, students will use pipe insulation to

build roller coasters for marbles to travel on.

Key Scientific Terms: gravity and velocity

Learning Targets:

I can use the engineering design process to design and build

a model roller coaster.

I can explain how roller coasters work.

I can calculate the average speed of my roller coaster.

Materials:

For each group, you will need:

1) Pipe insulation (2 three-foot long tube half pipes)

2) Masking tape

3) Stopwatch

4) Calculator

5) Cup

6) Marble

7) Ruler

8) String

9) Marble Roller Coaster Handout

Introduction (5 mins):

1. Explain to the students that today they will be roller coaster

engineers and will need to use their design and engineering skills to

build a roller coaster that fits a certain criteria using only the

materials provided.

2. Review the goal of today’s activity (to make the fastest roller

coaster).

3. Review definitions of design and engineer through the following

questions:

Can you recall what types of things an engineer works on? How does design relate to what engineers do?

Can you recall something that you designed?

Brainstorm and Design (10 mins):

4. Give each group their materials and the Marble Roller Coaster

Handout.

Grade Level:

All

Activity Time:

1 hour

Preparation Time:

5 minutes

Grouping:

2-3 students per

group


5. Ask students to sketch a drawing of their roller coaster within their groups. Roller

coasters should include at least 2 hills and 1 loop (maybe modified for younger ages- i.e.

1 hill/1 loop, or just 2 hills).

6. As students are working as open ended questions about their designs.

How does your design work? Why did you decide to make your design that way? What things do you think will affect your design works?

Are there other ways to design this? Explain.

Build:

7. Once students have finished design of their roller coaster provide them with the

materials to build their roller coasters.

8. Instruct them to use their environments (i.e. desks, chairs, the floor) to build their

roller coasters.

9. Check in with groups throughout the building phase with these questions:

Can you describe the different parts of the roller coaster and their purpose? Predict how you think your roller coaster is going to work. Does this activity remind you of something else you have build or experienced?

Test:

10. When they have finished building their roller coaster, have them test out the

worksheet. They will need to do the following:

a. Time how long the marble takes from the start of the roller coaster to the end.

Take a total of 5 time trials.

b. Find the average of the 5 time trials.

c. Figure out how far the marble traveled, by measuring the tubing they have been

given.

d. Use the average time and the distance traveled to calculate the average speed of

the marble.

e. Make a drawing/diagram of their marble roller coaster and label specific points.

Reflection and Discussion:

11. Once students have completed challenge, spend some time discussing the roller coaster

design/engineering process. Some possible discussion questions include:

Which designs worked best and why? What elements from other roller coasters could be combined with your design to

improve it?

What other types of engineers and careers do you think are involved in the process or designing and building a roller coaster?

Redesign (if time allots)


12. Have students redesign their roller coasts to try to make the marble travel faster.

Have them incorporate their new understandings from the reflection and discussion.

Science Connection:

When the marble is at the top of a hill, gravity is the force that acts upon it to put it into

motion. Steeper and longer roller coaster hills will result in an increase in the marble’s

velocity, or speed.


Today you will be a roller coaster engineer and will get to design your very own

marble roller coaster. Here are some guidelines for building your marble roller

coaster:

Your marble must not fall off until it gets to the end of the track.

The marble must land in the cup at the end of the run.

You may only use the materials provided (exception: if you need to, you may tape

your roller coaster to classroom furniture).

Challenge 1: Work with your team to build a roller coaster that has 2 hills (including the initial hill) and 1 vertical loop.

Sketch some ideas for how you might want your roller coaster to look:

Once you have completed your roller coaster answer the questions below:

Time Trial

Time the marble from start to finish five

different times. Start the time when the

marble is released at the beginning of your

track and end when it lands in the cup.

Trial Time (in seconds)

1

2

3

4

5


Average Time: Calculate the Average Time.

A) Add all your trials:

+ + + + =

Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial Total

B) Take the Trial Total time and divide by the number of trials (5) to get the average:

÷ 5 =

Trial Total Average Time

Average Speed: Calculate the Average Speed of your marble.

A) How far did your marble travel?

Using a piece of string measure out the length of the track. Track Length

B) To calculate speed, you need the distance the marble traveled (the length of the track)

and the time it took to travel:

÷ =

Track Length Average Time Average Speed


Diagram: Make a drawing of your roller coaster.

Label the highest point.

Label the point where the marble goes slowest.

Label the point where the marble goes fastest.

If you are finished with Challenge 1, you can move onto Challenge 2. You will have to

dismantle your previous roller coaster to make the next one.

Challenge 2: Join another team and combine your materials. Build a roller coaster that has

3 hills (including the initial hill) and 2 vertical loops.

Activity – Gumdrop Dome

Introduction: In this activity, students will use gumdrops and

toothpicks to build the structure that can hold the most weight.

Key Scientific Terms: compression and tension

Learning Targets:

I will be able to explain the engineering design process.

I will collaborate with my partner to design a structure.

Materials(per pair): 1) 50 toothpicks

2) 30 gumdrops

3) 1 paper plate

4) Gumdrop Dome handouts (optional)

5) Weights to test the strength of the dome structures (weights,

books, etc. Something that can hang from the structure)

Directions:

Introduction

1. Explain how forces can act differently on different shapes.

2. Have students make some simple shapes out of toothpicks

and gumdrops and test how strong they are. Have students make a

square and a triangle and then compare each ones’ strength. The

students should see that the triangle is the strongest.

3. Explain how and why dome structures are built the way they

are. Show some pictures of real domes. Make sure to include

pictures of geodesic domes (those built from a network of

triangles).

How would you describe the structures in the pictures? What types of shapes do you see in the pictures?

Give examples of some of your favorite structures that you have seen?

Brainstorm/Design

4. Introduce the challenge to the students. Explain to them

that they will be given 30 gumdrops and 50 toothpicks to build the

strongest dome that can hold the most weight.

5. In pairs, have the students brainstorm ideas about how they

might build their domes.

Grade Level:

All

Activity Time:

30 minutes

Preparation Time:

10 minutes

Grouping:

Pairs

Adapted from http://pbskids.org/zoom/activities/sci/gumdropdome.html


How could you apply what you have seen in structures to how you would build your dome?

Can you identify the different parts of your structure?

How does your design work? Why did you decide to make your design that way?

Build and Test

6. Pass out materials.

7. If the students seem stuck, pass out the Gumdrop Dome handout. Let students use

this handout as a resource guide.

8. Allow 30 minutes for students to design and build their domes.

9. Once finished, students can test the strength of their dome design by adding weights

until their structure fails (collapses).

What things do you think will affect how many weights your structure will hold?

What other materials would be helpful for building your structure?

What do you think will happen as you add more weights to your structure?

Reflection and Discussion

10. Once students have completed the challenge, spend some time discussing the design

process. Some possible discussion questions include:

Which structures held the most weights and why do you think so? How could you improve your design? What elements from other structures could be

combined to improve your structure? How would you apply what you learned to develop a structure using straw and

string?

Science Connection:

Trinagles are more stable shapes than squares. When you push down on a triangle the two

forces that act on it are balanced. Those two forces are compression and tension. In a

triangle, the compression in the two sides (as you push down on the point of a triangle) is

balanced by the tension in the piece along the bottom, which pulls the sides back together.


How to Build a Gumdrop Dome

Step 1

Build a pentagon with 5 gumdrops and 5

toothpicks. Lay it flat on the table.

Step 2

Build a triangle above each toothpick in

the pentagon. The triangles should stick

up into the air.

Connect the top gumdrops of each

triangle all the way around the pentagon.

Step 3

Stick one toothpick in the top of each

triangle. Lean the toothpicks together

towards the center and join them with a

gumdrop.

Test how strong this dome really is!

Use this basic structure to build an even bigger dome. Just make the base larger and

build the same triangle pattern all the way around. You can make it taller by adding

another row of triangles, too!

Activity – Building for the Big One

Introduction: In this activity, students will use limited materials to

build a structure on a type of simulated soil that can withstand an

“earthquake.”

Key Scientific Terms: center of gravity

Learning Targets:

I can work effectively as part of a team to brainstorm and

solve a problem.

I can describe the characteristics of a stable structure.

I can explain how soil type affects a building’s ability to

withstand an earthquake.

I understand the concept of limited resources and time

constraints.

Materials:

(per class) Rectangular pie pan or box lid (something that is large enough

to hold an 8in circular baking pan and to serve as the Shake Table)

Golf balls or similar balls

Stop watch

Playdough (2 containers)

Grape nuts (1 box)

Water

Oobleck (cornstarch and water)

Measuring cup

(per group) 20 popsicle sticks

1 roll of masking tape

1 golf ball

1 aluminum 8in circular baking pan

1 ruler

Several sheets of scratch paper and a pencil

Soil Types Handout

A set of Job Description Tags

Preparation:

Set up the Testing Zone by placing golf balls in a rectangular pie

Grade Level:

All

Activity Time:

1 hour

Preparation Time:

Grouping:

3-4 per group

*Adapted from: The Tech Museum of Innovation, San Jose, CA


pan to make the shake table. The structures built by students will be placed in a pie pan

on the shake table, which will be agitated back and forth for 15 seconds to simulate an

earthquake. Lay out the stop watch and paper towels (for cleanup).

The Shake Table

Directions:

Introduction:

1. Start a discussion about earthquakes.

Who has experienced an earthquake? What was it like?

What causes earthquakes?

What kind of damage can earthquakes cause? What can be done ahead of time

to reduce how much damage will take place?

2. Explain that the design challenge today is to build a structure that can withstand a

major earthquake using only a limited amount of materials.

3. Review definitions of design and engineer through the following questions:

Can you recall what types of things an engineer works on? How does design relate to what engineers do?

Can you recall something that you designed? 4. Explain the different careers involved in building an earthquake-proof structure.

Today the students will be taking on these roles.

The Geologist researches soil types by reading the Soil Types handout. Each

geologist will be given a different type of soil to work with. Based on that

information, he or she advises the architect and structural engineer on the

structure design. The geologist is the lead in the making of the soil inside of

the aluminum pan.

The Architect designs the structure based on the required specifications. He

or she works with the geologist to determine if the design will work with the

group’s specific soil type.

The Structural Engineer(s) builds the structure based on the architect’s design

and the geologist’s recommendations.

Brainstorm and Design:

5. Divide the students up into group of 3 or 4.


6. Pass out the Job Description Tags to each group and have each student in the group

take on one of the three roles (geologist, architect, or structural engineer). If there

are 4 students in the group, have two of the students be structural engineers.

7. Each team of students will be building their structure on a different type of soil and

will need to adapt their structure in order to be as stable as possible on that particular

type of soil.

8. Explain the following rules & specifications for their structures:

The structure can only be built with 20 popsicle sticks and masking tape

The structure must be at least 2 popsicle sticks tall

The structure must hold a person (represented by a golf ball) without shaking

them off or out of the structure

The base of their structure must fit into their aluminum baking pan

The structure must be able to withstand 15 seconds of shaking in the Testing

Zone without falling or collapsing.

9. Assign each group one of the four soil types (bedrock, alluvium, gravel, or landfill).

Provide all of the necessary materials listed below and pass out the Soil Types handout

to the geologist so they can research their particular type of soil.

Bedrock – fill a pie pan with Playdough

Alluvium – fill a pie pan with Grape Nuts and enough water to soak them, but not

to fill the pan

Gravel – fill a pie pan with dry Grape Nuts

Landfill – fill a pie pan with Oobleck (1 ½ cup of cornstarch + 1 cup of water)

10. Give students 5-10 minutes to brainstorm and design. During this period, the geologist

will research their group’s soil type and how to make the soil mixture. The architect

consults the geologist and draws up a design of the structure based on the required

specifications. The structural engineer plans ahead of time how he/she will construct

the structure.

Build and Test:

11. Give each group 15-20 minutes to build their structures.

12. Have all of the groups gather around the testing zone and call up each group to test

their structure. The entire group should participate in testing their structure.

Structures should be placed into their pan (filled with the correct soil type), placed

within the testing zone, and shaken for at least 15 seconds.


13. Follow up the activity with a discussion using the following questions.

What issues did you consider when designing your structure?

Which structures held up the best? Why? What features did you incorporate

to make your structure more stable? What types of features affect building

stability?


Foundation, shear force, support/reinforcement, triangles, wide to narrow (wide at base, narrow at top), low center of mass. How does what the structure is built on affect how much damage it takes?

What design changes or modifications will you consider for your next design?

What determines the magnitude of an earthquake?

Magnitude is a measure of the amount of energy released during an earthquake. The force is proportional to the amount of the energy released. This force travels spherically away from the point where energy is released (the focus).

Redesign (if time permits):

14. Have each group re-design and build their structure to be more stable. Emphasize

learning from testing and using ideas other groups used that were effective during

testing.

15. After each group has finished redesigning their structure, test each structure again.

Make sure to highlight the improvements the second time around.

16. Lead a discussion on the engineering design process and explain that the design

challenge they just completed is an example of utilizing this process to solve a problem.

Variations on this lesson plan:

In addition to testing whether a structure is earthquake-proof, you can challenge students

to see if their structure holds up to a rainstorm (simulated by spraying water from a spray

bottle) and windstorm (simulated by blowing a hairdryer).

Science Connection:

Having a low center of gravity (the point at which all of the weight of an object appears

to be concentrated) is essential for building a stable structure. This translates to

creating a structure, which is bottom heavy (i.e., wide at the base and narrow at the top).


Bedrock is the solid unweathered

rock that makes up the Earth’s

crust. The Earth’s outermost

surface is called the crust. Bedrock

may be composed of various

elements from region to region.

There are three major groups of

bedrock: sedimentary, metamorphic,

and igneous, each made of different

sets of minerals.

Alluvium is young sediment—

freshly eroded rock particles

that have come off the hillside

and been carried by streams.

Alluvium is pounded and ground

into finer and finer grains each

time it moves downstream.

Alluvium is typically made up of

a variety of materials, including

fine particles of clay and larger

particles of sand and gravel.

Gravel is any loose rock that is at

least 2mm and no more than 75mm.

It can be a mixture of sand, clay,

and small pieces of rock. It is

sedimentary rock and usually found

where there is, or were, rivers,

lakes, and glaciers. It happens

where rocks have been weathered

by wind or water or eroded.

A landfill is a site for the

disposal of waste materials by

burial such that it will be

isolated from groundwater and

will not be in contact with air.

Under these conditions, trash

will not decompose much.

Unless landfills are stabilized,

these areas may experience

severe shaking in a large

earthquake.


Directions: Cut-out and laminate the cards below and then attach them to a lanyard.

Geologist

The Geologist in the group will research and create the

group’s soil type: bedrock, alluvium, gravel, or landfill.

Soil Recipes:

Bedrock = Playdough

Alluvium Pan = Grapenuts + enough water to soak

them, but not fill the pan

Gravel Pan = Dry Grapenuts

Land fill = Oobleck (1 ½ cups of cornstarch + 1 cup

water)

Architect

The Architect in the group will design a structure that

meets the following parameters:

Parameters:

Structures must be at least two Popsicle sticks tall.

Structures must hold a golf ball without shaking it out

of the structure.

Structures must fit in a pan.

Structures must be able to withstand 15 seconds of

shaking without falling or collapsing (on shake table).

Structural

Engineer

The Structural Engineer(s) will build the

structure using popsicle sticks and 2 hot glue

sticks. Their structure must be based on the

Architect’s design and the Geologist’s

recommendations.

Structural

Engineer

The Structural Engineer(s) will build the

structure using popsicle sticks and 2 hot glue

sticks. Their structure must be based on the

Architect’s design and the Geologist’s

recommendations.

Activity – Paper Structures

Introduction: In this activity, students will try and build the

strongest structure using a limited amount of paper.

Key Scientific Terms: center of gravity

Learning Targets:

I can collaborate with my group members and listen to each

other’s ideas to complete a challenge

I can explain how to manipulate paper to make it hold more

weight

I can describe the types of careers involved in designing and

building a structure

Materials:

(per group) 1) 30 sheets of 8½” X 11” color paper (Give each group a different

color, if possible.)

2) One roll of masking tape (per class) 3) A class set of textbooks

Introduction:

1. Introduce the activity to the students by asking them to

describe some of the tallest or unique buildings or structures that

they have ever seen.

2. Lead a discussion about the types of careers that could be

involved in the process of designing and building a structure or

building.

3. Tell them that today they will be structural engineers who must

design and build the strongest structure using a limited amount of

paper and time. Their challenge is to build a structure at least 6

inches high which can support a book. They will have 5 minutes and

30 sheets of paper. They may not tape the structure to a table or

any other fixed structure.

Brainstorm:

4. Divide the class into teams.

5. Have each team brainstorm for 3 minutes possible designs for

their structures. As groups are brainstorming, ask open-ended

questions about their designs.

What types of designs do you think would be the strongest?

Grade Level:

All

Activity Time:

20 minutes

Grouping:

Groups of 2 – 3

*Adapted from SWE.org

Activity – Paper Structures

How can you manipulate paper to make it hold more weight?

Build and Test:

6. Give each team a stack of paper and a roll of masking tape. They will have 5 minutes to

build their structure.

7. Once the time is up, test each structure by placing a book on the structure. Continue

to add books until the structure collapses.


8. Once students have completed the challenge, spend some time discussing which

structures worked the best and ways to improve their group’s structures. Use the

following questions to guide the discussion.

Which structure was strongest and why? How did having a time limit affect your end product? How would you redesign your structure?

Some ways you can make a structure more stable is by:

Making the base wider

Taper the structure (Make the top skinny and the base wide)

Make the base heavier

Lower the center of gravity. The center of gravity is the point at which all of the

weight of an object appears to be concentrated.

Add more support points

Science Connection:

Having a low center of gravity (the point at which all of the weight of an object

appears to be concentrated) is essential for building a stable structure. This

translates to creating a structure, which is bottom heavy (i.e., wide at the base and

narrow at the top).

Activity – Straw Bridges

Introduction: In this activity, students will design and build the

strongest bridge using only straws, tape, and paper clips.

Key Scientific Terms: force, compression, and tension

Learning Targets:

I can work with my teammates to build the strongest bridge.

I can work with available resources to complete a challenge.

I can explain how engineers have to design structures using

limited resources (materials, money, manpower, and time).

Materials:

(per group) 25 straws

5” of tape

15 paper clips

Small weights

Directions:

Introduction:

1. Introduce the challenge to the youth. Imagine you are a

structural engineer and must design and build the strongest bridge

using the available resources. The goal of this activity it to build a

bridge that can hold the most weights before breaking.

2. Lead a discussion about how and why bridges are built the

way they are. Show pictures of real bridges or have students recall

how different bridges they have seen look like.

Describe what you notice about the various bridges in the pictures or bridges that you have seen

What are things that you think affect how strong a bridge is?

What types of careers are involved in designing and building a bridge?

Brainstorm and Design

3. Give each group their materials.

4. Have each group brainstorm possible designs for their

bridge using the available materials.

Grade Level:

All

Activity Time:

15 minutes

Preparation Time:

None


5. Have each group sketch out their design on a sheet of paper. As they are working, ask

them open ended questions about their design.

Summarize the parts of your design Have you ever done anything like this before?

Build:

6. Give each group 15 minutes to construct their bridge. As they are building, ask open-

ended questions about the design.

What are the different parts of your bridge and what is their purpose? How many weights do you think your bridge will hold and why?

What do you think will happen as we add weights to your bridge? What part do you think will begin to collapse first?

Test:

7. After all the groups have finished building their bridges, test the strength of each

bridge by placing one weight at a time until the bridge collapses. Record the number of

weights each group’s bridge can hold on a white board or chart paper.


8. Follow up the activity with a discussion using the following questions.

What elements would you change about your design and why? Suppose you could choose one additional material to use, what material would

you choose and why?

What was the most challenging aspect of this design challenge? How did you overcome this challenge?

Redesign:

9. If time permits, allow each group to go back and redesign their bridge. Emphasize

learning from testing and using ideas other groups used that were effective during

testing.

10. After each group has finished redesigning their bridge, test each bridge again. Make

sure to highlight the improvements the second time around. Record the number of

weights each group’s bridge can hold on a white board or chart paper.

11. Lead a discussion on the engineering design process and explain that the design

challenge they just completed is an example of utilizing this process to solve a problem.


What approach would you use to design the tallest structure using the same materials?

How do engineers work together to solve a problem? Defend the need for a process like the engineering design process to solve problems and design new products.

Science Connection:

The design of a bridge affects the amount of force that you can place on the bridge. Two

forces that every bridge has are tension and compression. Compression occurs when

something is being squeezed together. For example, as you sit in a chair, the legs of the

chair are experiencing compression because they are being squeezed between you and the

floor. Tension occurs when something is being pulled apart. A rope in a tug-o-war

experiences tension.

Handout – Engineering Design Process

©2011 by Techbridge. All rights reserved.

Printed in the United States of America.

This work may not be reproduced by mechanical or electronic means without the express written

permission of Techbridge. For permission to copy portions of this material for other purposes, please

email or call:

Techbridge

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Introduction Structural Engineering - Wikispacessciencelearningcommunity.wikispaces.com/file/view/... · · 2012-01-21Introduction – Structural Engineering ... the many factors

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