Fermilab LInC Online

The Bridges of Adams County

Scenario-1

Introduction:

Mr. Richard Kuhn is a Vocational Drafting Instructor at the Ohio Valley Vocational School. The Ohio Valley Vocational School is part of the Adams County/Ohio Valley Local School District. The school district is the largest school district geographically in the State of Ohio, encompassing more than six hundred square miles. Small towns and villages dot the primary rural area the area. The Drafting class is made up of juniors and seniors from throughout the district. Mr. Kuhn is constantly looking for ways to impress upon his students the practical aspect of the Drafting Industry. Due to the recent flooding that has occurred in the area, many of the bridges within the county were either destroyed or damaged. With this in mind, Mr. Kuhn is instituting a third trimester project which is an Engaged Learning, student driven project. The project will provide the class with an opportunity to work on the project as a team. Through the use of computer software and basic drafting fundamentals, the students will study the engineering concepts needed in bridge design and apply those concepts to hopefully help the community plan for the replacement and improvement of the county's bridge system. Through this project the students will demonstrate the ability to:

• Use the scientific process.
  
• Apply their understanding of bridge design to a real-world problem.
  

It is the hope of the author that this project will have a positive impact on the students and that the community will recognize their work.

Scenario:

In an effort to introduce the Senior Drafting class to practical engineering applications and to help build their skills in team work, the teacher introduces the class to the Bridge Building Project.

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The Computer Lab has ten IBM compatible computers connected to the lab's server, which in turn is connected to the communication server of the school and to the Internet via a T-1 line. Students have had the opportunity during the school year to complete Internet activities that familiarized them with the Internet and the use of its technology.

The teacher begins the class by showing several videos about the basic concepts of bridge design. Following the viewing of the videos the teacher shows the video "The Flood of 97". This video shows flood damaged bridges from around the local area. After the videos have been shown, the teacher ask the students to try to explain why the local bridges suffered so much damage during the spring flood of 1997.

After brainstorming, the teacher asks the students to list the possible causes of the bridge failures. The students choose a member of the class to record their ideas. The students listed several possible causes that they believe contributed to the failures of the bridges. Before the end of class, the juniors divide up into teams with a senior who will act as a project coordinator. Due to early placement opportunities, team make-up and assignments will be determined by the number of student members that remain in class.

The next day the students are given a list of some of the web sites that the teacher has found that deal with bridges and bridge design. (Student Pages) The students are also introduced to basic structural strengths of materials and the associated math that will be used to analyze their bridge designs. The students begin to investigate further their reasons for the bridge failures during the floods.

Over the next several days, class is held in the computer lab. The students are given a sheet on which to record the web sites and e-mail addresses dealing with bridge design that they discover during their time on the Internet. This is done so that the students will have a record of the sites that they have visited and that this record may be used to develop a bibliography page for the project's web site.

During this time, the teacher has been arranging for a speaker to come into the class and talk to the students about basic bridge design. The speaker is Mr. Gerald Wallingford, Adams County Engineer. During Mr. Wallingford's talk, he explains to the students what factors his office must consider when design or replacing a bridge. He tells the students that many of the county bridges were design in the early nineteen hundreds and they were not designed to take the punishment of today's traffic. He tells the students that many of the bridges are in locations that subject them to not only abusive traffic but also to the forces of nature. This problem became much more evident during the floods, when several of the county's bridges were either heavily damaged or destroyed. The bridges are located in areas that are receiving more water run-off then when the were first built. This run-off is coming from the development of the surrounding farmlands that is occurring throughout the county. He explains to the students that the bridge supports are being undercut by the water flowing through the streams and creeks that the bridges transverse. Mr. Wallingford tells the students that his office is currently reviewing better that half of the bridges within the county for structural soundness.

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Following his talk Mr. Wallingford invites the students to visit his office and some of the bridge sites that his office is currently checking and sites where bridges are being repaired or replaced. The students accept his offer and a time for the following Monday is set to visit some of the bridge sites.

The students visit the sites on Monday, during their visit they examine the bridge footings and supports that are being worn away by the constant flow of water. Pictures are taken of the bridge damage and of the repairs that are being made. Pictures are also taken of the roadway leading to and from the bridges.

Following the return to school, one of the students is assigned the task of having the pictures developed and then scanned for insertion on to the project's web page.

The students continue their work covering the math and design concepts. As part of the design concepts, the students are introduced to a computer software package that will help them with their design analysis. The computer program allows the student to determine the span of a bridge, the type of foundation for the bridge, the type of materials (balsa or basswood) used to construct a model of the bridge, and the weight applied to the bridge.

As part of their assignment, the students are required to design a bridge. This bridge is to be designed by using the information that they have gained from the Internet sites that they have visited along with the information that they have been able to receive through their discussions with local and distant experts via e-mail. By using the computer program for analysis, the students are able to check their bridge designs for structural soundness. Once the bridge design meets the requirements that the students have set for themselves, they submit their design to the software company for analysis and enter the design in the companies design contest. As the students complete their computer bridge designs, they begin work on drawing a scale model of their bridge. The students are drawing plans for their model at a scale of 3/4 inch equals 1 foot.

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After their plans have been drawn and check by the teacher, the students begin to work on the actual scale model of their design. The model is being built out of balsa wood that is cut to scale. The students are using only balsa wood and wood glue to build their model. They work in teams with each team responsible for a different component of the bridge. Several students are responsible for cutting the wood to the proper size while others are putting the pieces together to form the super structure of the bridge. The bridge is taking shape as the pieces are put together. The super structure is tied together and the glue is allowed to dry before the "road" deck is placed on the bridge.

After allowing the whole structure to dry completely, the bridge is tested. Students from the Principles of Technology class have brought their bridge models into the Drafting Lab to see which class has designed the best bridge. The students examine the bridge structures and analyze each other's work.

The students test their bridge by placing standard size bricks on the center of the "road" deck. The students weigh each brick before it is placed on the bridge, this is so an accurate record of the amount of weight placed on the bridge can be kept. The tension mounts as each brick is placed on the bridge. The students listen intently for the first sounds of failure, that first crack.

As part of their final project, the students of the Drafting class, through the use of a Powerpoint presentation that has been prepared by the project coordinators, will present to the County Engineer their findings as to the possible location and design of new highway bridges and overpasses for the county.

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