QUIZ Structural Design 1

Name Date

Science Class

PRACTICE QUIZ Structural Design—BridgesPart 1 Bridge Design

Study Guide

Review Five classic bridge types, and how they deal with forces of tension and compression.

Overview ideas of how to choose a bridge design for a particular location (e.g. span

distance, clearance requirements, etc).

Working use of bridge vocabulary

Understanding of how shapes contribute (or not) to structural stability (square,

triangle, arches).

Understanding of the tradeoffs encountered in using different building materials

(focus on concrete and steel)

Study Resources

Class activity and handout “Paper Bridges”

Handout “Corrugated Cardboard as a Truss Structure”

Reference handout “Bridge Design and Materials”

Applied understanding “Build a Bridge”

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Here is a portion of a cable stay bridge. How does this bridge design handle forces of tension

and compression? Use this diagram for questions 1-2.

Practice1. The forces that go down the piers are

a. compression forces

b. tension forces

Practice2. The cabling that connects the tower to the roadway is

a. under tension

b. under compression

Every bridge design has advantages and disadvantages. For each of the next two questions,

identify and correct the false statement.

Practice3. The beam bridge design

a. is a low-cost choice.

b. requires under support at close intervals.

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c. is suitable for spans that require a lot of clearance (e.g. passing ships). (NOT)

d. is perhaps the most ancient bridge structure.

Practice4. The suspension bridge design

a. uses some materials that can tolerate tension.

b. uses some materials that can tolerate compression.

c. is the bridge of choice for the longest spans.

d. is relatively heavy and stiff (LIGHT AND FLEXIBLE).

Practice5. Loads are forces applied to a bridge. These forces can be vertical or horizontal. One

vertical force is the weight of the bridge itself. Name two others.

Another vertical force is the weight of vehicles crossing the bridge.

Another vertical force is accumulated snow and ice.

Another vertical force can be the wind.

Another vertical force can be the settling of the ground under a bridge, either gradual, or

intense, like an earthquake.

The Golden Gate Bridge in

California is a famous landmark.

It was built to span a mile-wide

channel between San Francisco

Bay and the Pacific Ocean. The

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water here is very deep and fast flowing. The area is also known for its winds, intense fog, and

corrosive salt air. Construction began in 1933, and the bridge opened in 1937. The next two

questions are about this bridge.

Practice6. The Golden Gate Bridge needs a lot of attention; it has a fulltime maintenance crew.

Match each need with a maintenance strategy.

A. Need for waterproofing

B. Need to reduce the dead load

C. Need to reduce the twisting of the deck in high winds

D. Need to protect against earthquakes

A Strategy: Regular painting

D Strategy: Retrofitting the bridge with devices that distribute energy.

B Strategy: Replacing the road deck with a lighter material

C Strategy: Bracing the bottom of the deck

Practice7. Building the Golden Gate bridge was a dangerous task.

Match the safety equipment used with its purpose.

A. Need to see in dark, enclosed areas.

B. Need to protect against small pieces of falling debris.

C. Need to shield against the strong winds

B Equipment: helmets

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A Equipment: headlamps

C Equipment: goggles

The Millau Viaduct under construction. The finished bridge.

The Millau Viaduct in France was designed to last for 120 years. Construction began in 2001,

and the bridge opened in 2004. For several years, this cable stay bridge held the world record

as the tallest bridge in the world. There are seven piers supporting this bridge, each a different

height to match the sloping ground below. The next two questions are about this bridge.

Practice8. The roadway for the Millau Viaduct was built in two parts. Starting at each end of the

span, the roadway sections were launched slowly toward each other to meet in the middle.

When the non-stick Teflon surfaces on one of the launching systems ripped, this caused a

problem due to increased

a. Friction

b. Gravity

c. Mass

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d. Volume

Practice9. The roadway of the Millau Viaduct is made of steel. When it was first installed it was

rippling and sagging, due to its own weight. Which bridge part on a cable stay design like this

helps to straighten out the roadway?

a. The piers

b. The cables

c. The anchor

d. The keystone

The Anji Bridge in China was built over 1,400 years ago, over a river that carried a lot of boat

traffic, and that was also known for periodic flooding.

Practice10. What part of this structure enables it to withstand floodwaters? Explain your

thinking.

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The holes cut into the bridge enable water to pass through the bridge instead of against it.

This means that the force of the floodwaters will not have as much effect on the bridge.

Part 2. Scientific Method

Practice. Concrete is an important

building material. Its three key

ingredients are water, cement, and rock

material. Once mixed, a chemical

reaction called hydration occurs, and you

get concrete. The “recipe” you use

influences the resulting concrete’s

strength, permeability, and durability. The amount of water used can also influence how much

shrinking and cracking take place during drying. Ray and Felicia want to make some concrete

stepping blocks for their new garden path. They decide to do some test blocks first by changing

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the amount of water added. They will use the recipe that results in the least shrinking and

cracking.

Basic recipe 1 part water 2 parts cement 3 parts sand 3 parts gravel

Variation 1 ¾ part water 2 parts cement 3 parts sand 3 parts gravel

Variation 2 1-1/4 parts water 2 parts cement 3 parts sand 3 parts gravel

Practice11. What is the guiding question for this investigation?

Which amount of water results in concrete that has the least cracking and shrinking?

Practice12. What is a suitable hypothesis?

The basic recipe will result in the least cracking and shrinking.

Practice13. What is the independent variable?

The amount of water used

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Practice14. What is the dependent variable?

There are two dependent variables—amount of cracking, and amount of shrinking.

Practice15. What are two controls you should use to make this investigation fair?

Use all of the other same ingredients, use the same mold to make all the sample stepping

blocks, allow the same amount of drying time, etc.