bridge construction. objectives given pictures of bridges, students will be able to identify the...

Bridge Bridge ConstructionConstruction

ObjectivesObjectives

Given pictures of bridges, students Given pictures of bridges, students will be able to identify the basic will be able to identify the basic types of bridges.types of bridges.

Without any aid, students will be Without any aid, students will be able to describe the 7 steps of the able to describe the 7 steps of the engineering process with 100% engineering process with 100% accuracy.accuracy.

Table of ContentsTable of Contents

Types of Bridges Engineering Process Quiz References

Means Link back to this page here

Types of BridgesTypes of Bridges

IntroductionIntroduction- A bridge is a structure that permits you to cross over an A bridge is a structure that permits you to cross over an

obstacle. obstacle. - Suppose you lay a plank across a brook. You have a bridge. Suppose you lay a plank across a brook. You have a bridge.

If the plank is thin in relation to its length, it will sag. In If the plank is thin in relation to its length, it will sag. In fact, if it is too long, it will collapse. This shows that you fact, if it is too long, it will collapse. This shows that you must consider the weight of a bridge itself---the “dead must consider the weight of a bridge itself---the “dead load”.load”.

- If you stand at the middle of the plank, it sags even more. If you stand at the middle of the plank, it sags even more. So, you must provide for the weight of whatever your So, you must provide for the weight of whatever your bridge is designed to carry---the “live load”.bridge is designed to carry---the “live load”.

- Also, when you walk across the plank, it bounces under Also, when you walk across the plank, it bounces under you, illustrating the effect of a “moving live load”.you, illustrating the effect of a “moving live load”.

- Finally, there is a “wind load”. A strong wind pushes Finally, there is a “wind load”. A strong wind pushes against the sides, lifts the deck, shakes the whole against the sides, lifts the deck, shakes the whole structure. Certainly the force of the wind is something to structure. Certainly the force of the wind is something to keep in mind. keep in mind.

- Bridges help us to connect to each other and the world. Bridges help us to connect to each other and the world. - There are four main types of physical bridges. They are There are four main types of physical bridges. They are

arch, beam, suspension and cable-stayed.arch, beam, suspension and cable-stayed.


Beam BridgeBeam Bridge- A beam or "girder" bridge is the simplest and most A beam or "girder" bridge is the simplest and most

inexpensive kind of bridge.inexpensive kind of bridge.- In its most basic form, a beam bridge consists of a In its most basic form, a beam bridge consists of a

horizontal beam that is supported at each end by horizontal beam that is supported at each end by piers-vertical structures at the end of a bridge piers-vertical structures at the end of a bridge which support the weight of the bridge. The which support the weight of the bridge. The weight of the beam pushes straight down on the weight of the beam pushes straight down on the piers.piers.

- The beam itself must be strong so that it doesn't The beam itself must be strong so that it doesn't bend under its own weight and the added weight bend under its own weight and the added weight of crossing traffic. of crossing traffic.

- When a load pushes down on the beam, the beam's When a load pushes down on the beam, the beam's top edge is pushed together (compression) while top edge is pushed together (compression) while the bottom edge is stretched (tension). the bottom edge is stretched (tension).


Beam BridgeBeam Bridge

Basic Beam BridgeActual Beam Bridge


Arch BridgeArch Bridge- Arch bridges are one of the oldest types of Arch bridges are one of the oldest types of

bridges and have great natural strength. bridges and have great natural strength. - Instead of pushing straight down, the Instead of pushing straight down, the

weight of an arch bridge is carried weight of an arch bridge is carried outward along the curve of the arch to the outward along the curve of the arch to the supports at each end. supports at each end.

- These supports, called the abutments, These supports, called the abutments, carry the load and keep the ends of the carry the load and keep the ends of the bridge from spreading out. bridge from spreading out.


Arch BridgeArch Bridge

Basic Arch Bridge Actual Arch Bridge

Bixby Creek Bridge, Monterey, CA


Suspension BridgeSuspension Bridge- Aesthetic, light, and strong, suspension bridges Aesthetic, light, and strong, suspension bridges

can span distances from 2,000 to 7,000 feet -- can span distances from 2,000 to 7,000 feet -- far longer than any other kind of bridge. far longer than any other kind of bridge.

- They also tend to be the most expensive to They also tend to be the most expensive to build. build.

- True to its name, a suspension bridge suspendsTrue to its name, a suspension bridge suspends the roadway from huge main cables, which the roadway from huge main cables, which extend from one end of the bridge to the other. extend from one end of the bridge to the other.

- These cables rest on top of high towers and are These cables rest on top of high towers and are secured at each end by secured at each end by anchoragesanchorages. .


Suspension BridgeSuspension Bridge- The towers enable the main cables to be draped The towers enable the main cables to be draped

over long distances. over long distances. - Most of the weight of the bridge is carried by the Most of the weight of the bridge is carried by the

cables to the anchorages, which are imbedded in cables to the anchorages, which are imbedded in either solid rock or massive concrete blocks. either solid rock or massive concrete blocks.

- Inside the anchorages, the cables are spread Inside the anchorages, the cables are spread over a large area to evenly distribute the load over a large area to evenly distribute the load and to prevent the cables from breaking free.and to prevent the cables from breaking free.

- What is the difference between an abutment and What is the difference between an abutment and an anchorage?an anchorage?


Suspension BridgeSuspension Bridge

Basic Suspension BridgeActual Suspension Bridge

Golden Gate Bridge, San Francisco, CA


Cable-stayed BridgeCable-stayed Bridge- Cable-stayed bridges may look similar to Cable-stayed bridges may look similar to

suspensions bridges -- both have roadways that suspensions bridges -- both have roadways that hang from cables and both have towers. hang from cables and both have towers.

- The two bridges support the load of the roadway The two bridges support the load of the roadway in very different ways. in very different ways.

- The difference lies in how the cables are The difference lies in how the cables are connected to the towers. In suspension bridges, connected to the towers. In suspension bridges, the cables ride freely across the towers, the cables ride freely across the towers, transmitting the load to the anchorages at either transmitting the load to the anchorages at either end. end.

- In cable-stayeded bridges, the cables are In cable-stayeded bridges, the cables are attached to the towers, which alone bear the attached to the towers, which alone bear the load.load.


Cable-stayed BridgeCable-stayed Bridge- The cables can be attached to the roadway The cables can be attached to the roadway

in a variety of ways. in a variety of ways. - In a radial pattern, cables extend from In a radial pattern, cables extend from

several points on the road to a single point several points on the road to a single point at the top of the tower. at the top of the tower.

- In a parallel pattern, cables are attached at In a parallel pattern, cables are attached at different heights along the tower, running different heights along the tower, running parallel to one other. parallel to one other.


Cable-stayed BridgeCable-stayed Bridge

Basic Cable-stayed Bridge Actual Cable-stayed BridgeClark Bridge, Alton, IL


ReviewReviewTo review for the types of bridges, go to To review for the types of bridges, go to

http://bridgepros.com/

Click on the Learning Center at the top of Click on the Learning Center at the top of the screen. Click on the Build Bridge link. the screen. Click on the Build Bridge link. Complete the Bridge game at the bottom Complete the Bridge game at the bottom of this page.of this page.

Engineering ProcessEngineering Process

IntroIntro

The engineering process is an extension of the scientific The engineering process is an extension of the scientific method. Teaching students to use this process when method. Teaching students to use this process when they begin to build their bridges will provide them they begin to build their bridges will provide them with valuable skills to use when it comes to solving with valuable skills to use when it comes to solving

problems or creating a project. The engineering problems or creating a project. The engineering process includes basic procedures that engineers use process includes basic procedures that engineers use to identify the problem and determine an adequate to identify the problem and determine an adequate solution to the challenge they have undertaken. The solution to the challenge they have undertaken. The

engineering process can be broken down into the engineering process can be broken down into the following eight simple steps. following eight simple steps.


Identify the ProblemIdentify the Problem

Before the engineer can begin work, Before the engineer can begin work, the problem or task that is going to the problem or task that is going to

be undertaken must be known. be undertaken must be known.


Determine ConstraintsDetermine Constraints

Constraints are the limitations that Constraints are the limitations that must be considered before you begin must be considered before you begin designing your bridge. Even though designing your bridge. Even though they are not limited to the materials, they are not limited to the materials,

size, and money, you have to size, and money, you have to consider them the problem or task. consider them the problem or task.


Analysis of DesignAnalysis of Design

During this step, the designs are studied During this step, the designs are studied based on their merit in relationship to based on their merit in relationship to

strength, cost, market appeal, and strength, cost, market appeal, and manufacturability. Models, drawings manufacturability. Models, drawings and calculations can be presented at and calculations can be presented at this stage. A decision should be made this stage. A decision should be made at this point on which design to use or at this point on which design to use or

rather to begin a new design. rather to begin a new design.


Design RefinementDesign Refinement

This step begins after a design has been This step begins after a design has been analyzed. Any problems or unresolved analyzed. Any problems or unresolved

considerations with the design should have considerations with the design should have been made apparent by now. Each design team been made apparent by now. Each design team

should attempt to rectify the problems by should attempt to rectify the problems by making improvements in the design. After the making improvements in the design. After the corrections have been made, then each team corrections have been made, then each team should go back and analyze the design once should go back and analyze the design once

again. again.


Implementation PlanImplementation Plan

Once the final design has been approved, it must be Once the final design has been approved, it must be translated from an idea on paper to the real thing. translated from an idea on paper to the real thing. Before the plan can be implemented, plans need to Before the plan can be implemented, plans need to

be made outlining the construction process. The be made outlining the construction process. The methods of construction together with the strategy methods of construction together with the strategy

for scheduling involved a list of the tools; machinery for scheduling involved a list of the tools; machinery and materials needed to complete the project. A and materials needed to complete the project. A

listing of the parts and the dimension of the project listing of the parts and the dimension of the project are drawn up. The order is which the bridge is to be are drawn up. The order is which the bridge is to be built is also written down and the specifications are built is also written down and the specifications are

compiled. compiled.


Modify the ImplementationModify the Implementation

Any obstacles that may arise during Any obstacles that may arise during the building of the bridge must be the building of the bridge must be

analyzed in order to find out if it is a analyzed in order to find out if it is a big enough problem to cause a big enough problem to cause a

change in the original plan. change in the original plan.


ImplementationImplementation

The final step is to manufacture the individual The final step is to manufacture the individual parts as prescribed in the implementation parts as prescribed in the implementation

plans. Even though the steps are listed in a plans. Even though the steps are listed in a specific order, in real life two or more of these specific order, in real life two or more of these steps maybe combined or done in a different steps maybe combined or done in a different order. In the field of engineering, sometimes order. In the field of engineering, sometimes one person may specialize in a certain step, one person may specialize in a certain step,

but the method is always followed in one but the method is always followed in one respect or the other. respect or the other.


ReviewReviewThe seven steps to the Engineering Process The seven steps to the Engineering Process

are:are:- Identify the ProblemIdentify the Problem- Determine ConstraintsDetermine Constraints- Analysis of DesignAnalysis of Design- Design RefinementDesign Refinement- Implementation PlanImplementation Plan- Modify the ImplementationModify the Implementation- ImplementationImplementation

QuizQuiz

Question 1:Question 1:

What are the oldest type of Bridges?What are the oldest type of Bridges?A. Beam BeamB. Arch ArchC. Cable-stayed Cable-stayedD. Suspension Suspension

Click after you get right answer

QuizQuiz


Which type of bridge is normally the Which type of bridge is normally the longest type?longest type?

A. Beam BeamB. Arch ArchC. Cable-stayed Cable-stayedD. Suspension Suspension


QuizQuiz

Question 3: Question 3:

Which type of bridge is the cheapest?Which type of bridge is the cheapest?A. Beam BeamB. Arch ArchC. Cable-stayed Cable-stayedD. Suspension Suspension


QuizQuiz

Question 4: Question 4:

What is the fourth step of the What is the fourth step of the Engineering Process?Engineering Process?

A. Design Refinement Design RefinementB. Implementation Implementation

C. Determine ConstraintsC. Determine Constraints

D. Implementation PlanD. Implementation PlanClick after you get right answer

QuizQuiz


During this step, the designs are studied During this step, the designs are studied based on their merit in relationship to based on their merit in relationship to strength, cost, market appeal, and strength, cost, market appeal, and manufacturability. manufacturability.

A. Identify ProblemsA. Identify Problems

B. Modify the ImplementationB. Modify the Implementation

C. Determine ConstraintsC. Determine Constraints

D. Analysis of DesignD. Analysis of Design

Correct!Correct!

Go back and move on to next Go back and move on to next question!question!

Sorry!Sorry!

Go back and try a different answer!Go back and try a different answer!

Congratulations, you’ve completed Congratulations, you’ve completed

the activity!the activity!

ReferencesReferences

http://bridgepros.com/http://bridgepros.com/ http://www.yale.edu/ynhti/http://www.yale.edu/ynhti/

curriculum/units/curriculum/units/2001/5/01.05.04.x.html#b2001/5/01.05.04.x.html#b

http://www.mediaworkshop.org/http://www.mediaworkshop.org/ashs/cole/types.htmashs/cole/types.htm

bridge construction. objectives given pictures of bridges, students will be able to identify the...

Documents

girder bridge

inexpensive kind of

basic types of bridges

oldest types of bridges

horizontal beam

main types of physical

suspension bridges

wind load