bridge construction for class

7/29/2019 Bridge Construction for Class

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Bridge Construction


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Objectives

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

Without any aid, students will be able todescribe the 7 steps of the engineering processwith 100% accuracy.


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Table of Contents

Types of Bridges

Engineering Process

Quiz References

Means Link back to

this page here


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Types of Bridges

Introduction- A bridge is a structure that permits you to cross over an obstacle.- 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 fact, if it is too long, it will collapse.

This shows that you must consider the weight of a bridge itself---the deadload.- If you stand at the middle of the plank, it sags even more. So, you must

provide for the weight of whatever your bridge is designed to carry---the liveload.

- Also, when you walk across the plank, it bounces under you, illustrating the

effect of a moving live load.- Finally, there is a wind load. A strong wind pushes against the sides, lifts thedeck, shakes the whole structure. Certainly the force of the wind is somethingto keep in mind.

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

suspension and cable-stayed.


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Types of Bridges

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

inexpensive kind of bridge.

- In its most basic form, a beam bridge consists of ahorizontal beam that is supported at each end by piers. Theweight of the beam pushes straight down on the piers.

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

traffic.- When a load pushes down on the beam, the beam's top

edge is pushed together (compression) while the bottomedge is stretched (tension).


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Types of Bridges

Beam Bridge

Basic Beam BridgeActual Beam Bridge
http://www.pbs.org/wgbh/nova/bridge/meetbeam.html


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Types of Bridges

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

bridges and have great natural strength.

- Instead of pushing straight down, the weight ofan arch bridge is carried outward along the curveof the arch to the supports at each end.

- These supports, called the abutments, carry theload and keep the ends of the bridge fromspreading out.


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Types of Bridges

Arch Bridge

Basic Arch BridgeActual Arch Bridge

Bixby Creek Bridge, Monterey, CA
http://www.pbs.org/wgbh/nova/bridge/meetarch.html


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Types of Bridges

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

span distances from 2,000 to 7,000 feet -- far longer

than any other kind of bridge.- They also tend to be the most expensive to build.- True to its name, a suspension bridge suspendsthe

roadway from huge main cables, which extend fromone end of the bridge to the other.

- These cables rest on top of high towers and are securedat each end by anchorages.


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Types of Bridges

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

long distances.

- Most of the weight of the bridge is carried by the cablesto the anchorages, which are imbedded in either solidrock or massive concrete blocks.

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


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Types of Bridges

Suspension Bridge

Basic Suspension BridgeActual Suspension Bridge

Golden Gate Bridge, San Francisco, CA
http://www.pbs.org/wgbh/nova/bridge/meetsusp.html


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Types of Bridges

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

bridges -- both have roadways that hang from cables andboth have towers.

- Two bridges support the load of the roadway in verydifferent ways.

- The difference lies in how the cables are connected to thetowers. In suspension bridges, the cables ride freely across

the towers, transmitting the load to the anchorages at eitherend.- In cable-stayeded bridges, the cables are attached to the

towers, which alone bear the load.


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Types of Bridges

Cable-stayed Bridge- The cables can be attached to the roadway in a variety

of ways.

- In a radial pattern, cables extend from several points onthe road to a single point at the top of the tower.

- In a parallel pattern, cables are attached at different

heights along the tower, running parallel to one other.


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Types of Bridges

Cable-stayed Bridge

Basic Cable-stayed Bridge Actual Cable-stayed BridgeClark Bridge, Alton, IL
http://www.pbs.org/wgbh/nova/bridge/meetcable.html


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Types of Bridges

ReviewTo review for the types of bridges, go to

http://bridgepros.com/

Click on the Learning Center at the top of the screen.Click on the Build Bridge link. Complete the Bridge

game at the bottom of this page.
http://bridgepros.com/http://bridgepros.com/


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Engineering Process

Intro

The engineering process is an extension of the scientific method.Teaching students to use this process when they begin to buildtheir bridges will provide them with valuable skills to use when itcomes to solving problems or creating a project. The engineeringprocess includes basic procedures that engineers use to identify

the problem and determine an adequate solution to the challengethey have undertaken. The engineering process can be brokendown into the following eight simple steps.


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Engineering Process

Identify the Problem

Before the engineer can begin work, the problemor task that is going to be undertaken must be

known.


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Engineering Process

Determine Constraints

Constraints are the limitations that must beconsidered before you begin designing your

bridge. Even though they are not limited to the

materials, size, and money, you have to considerthem the problem or task.


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Engineering Process

Analysis of Design

During this step, the designs are studied based ontheir merit in relationship to strength, cost,market appeal, and manufacturability. Models,drawings and calculations can be presented at

this stage. A decision should be made at thispoint on which design to use or rather to begin a

new design.


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Engineering Process

Design Refinement

This step begins after a design has been analyzed. Anyproblems or unresolved considerations with the designshould have been made apparent by now. Each designteam should attempt to rectify the problems by making

improvements in the design. After the corrections havebeen made, then each team should go back and analyze

the design once again.


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Engineering Process

Implementation Plan

Once the final design has been approved, it must be translated froman idea on paper to the real thing. Before the plan can be

implemented, plans need to be made outlining the constructionprocess. The methods of construction together with the strategy

for scheduling involved a list of the tools; machinery andmaterials needed to complete the project. A listing of the partsand the dimension of the project are drawn up. The order iswhich the bridge is to be built is also written down and the

specifications are compiled.


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Engineering Process

Modify the Implementation

Any obstacles that may arise during the building ofthe bridge must be analyzed in order to find outif it is a big enough problem to cause a change

in the original plan.


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Engineering Process

Implementation

The final step is to manufacture the individual parts asprescribed in the implementation plans. Even thoughthe steps are listed in a specific order, in real life two or

more of these steps maybe combined or done in a

different order. In the field of engineering, sometimesone person may specialize in a certain step, but the

method is always followed in one respect or the other.


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Engineering Process

ReviewThe seven steps to the Engineering Process are:

- Identify the Problem

- Determine Constraints- Analysis of Design

- Design Refinement

- Implementation Plan- Modify the Implementation

- Implementation


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Quiz

Question 1:

What are the oldest type of Bridges?

A. BeamB. Arch

C. Cable-stayed

D. Suspension

Click after you get

right answer


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Quiz

Question 2:

Which type of bridge is normally the longest type?

A. BeamB. Arch

C. Cable-stayed

D. Suspension

Click after you get

right answer


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Quiz

Question 3:

Which type of bridge is the cheapest?

A. BeamB. Arch

C. Cable-stayed

D. Suspension

Click after you get

right answer


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Quiz

Question 4:

What is the fourth step of the EngineeringProcess?

A. Design Refinement

B. Implementation

C. Determine ConstraintsD. Implementation Plan

Click after you get

right answer


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Quiz

Question 5:

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

A. Identify Problems

B. Modify the Implementation

C. Determine Constraints

D. Analysis of Design


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Correct!

Go back and move on to next question!


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Sorry!

Go back and try a different answer!


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Congratulations, youve completed

the activity!


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References

http://bridgepros.com/

http://www.yale.edu/ynhti/curriculum/units/2001/5/01.05.04.x.html#b

http://www.mediaworkshop.org/ashs/cole/types.htm
http://bridgepros.com/http://www.yale.edu/ynhti/curriculum/units/2001/5/01.05.04.x.htmlhttp://www.yale.edu/ynhti/curriculum/units/2001/5/01.05.04.x.htmlhttp://www.mediaworkshop.org/ashs/cole/types.htmhttp://www.mediaworkshop.org/ashs/cole/types.htmhttp://www.mediaworkshop.org/ashs/cole/types.htmhttp://www.mediaworkshop.org/ashs/cole/types.htmhttp://www.yale.edu/ynhti/curriculum/units/2001/5/01.05.04.x.htmlhttp://www.yale.edu/ynhti/curriculum/units/2001/5/01.05.04.x.htmlhttp://bridgepros.com/

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