DESCRIPTION:

Students will design, construct, and test a wooden bridge spanning a space of 35.0 centimeters.

MATERIALS:

1. The bridge is to be a single structure constructed of wood bonded by glue.
2. No other materials shall be used.
3. Particleboard, plywood, wood products, or commercially laminated wood may not be used.
4. The entire bridge, including the road surface, must be constructed of pieces of wood no larger than ¼” high and ¼” wide. Any dowels used cannot have a diameter larger than ¼”.
5. There is no limit on the length of individual wood pieces used in construction.
6. Any type of bonding material (glue) may be used.

CONSTRUCTION:

1. Any type of bridge that meets the specifications below may be constructed. Sound engineering practices such as truss construction, gussets, and mitered joints are encouraged.
2. All construction must be completed prior to the competition.
3. The bridge may not be coated with any material, e.g., paint, stain, glue.
4. Bridge dimensions
   1. Span
      1. For final evaluation, the bridge will be supported by two vertical supports, 350 mm apart. There is no maximum length of the bridge.

      Width

      1. The inside dimension of the road surface must be greater than 80 mm so that an 80 mm wide loading block will fit between the sides of the road surface and so a piece of paper will fit on each side of the block. There is no maximum width of the bridge.

      No portion of the bridge may extend more than 10 mm below the top surface of the test supports.

5. Bridge mass limit is 0.68 kg.
6. The road surface is defined as a surface or surfaces that must allow the free passage of a rolling MatchboxTM or Hot WheelsTM model car along its entire length. The car must have an axle width of 30 + 5 mm. The surface does not have to be solid.
   1. a. Raised curbs, rails, or tracks are permitted and become an extension of the road surface on which the loading block may rest.

      b. Length- The length of the road surface must extend across the entire length of the bridge.

      c. Height- The height of the road surface must not exceed 10 mm above the top surface of the test supports at any point.

7. Loading
   1. a. The load point will be the midpoint of the centerline of the bridge.

      b. The bridge must accommodate a 50 mm long x 80 mm x 20 mm high loading block (provided at the testing site). A hole large enough to accommodate a ¼” rod must be provided through the road surface. The rod (provided at the testing site) is used to apply load to the bridge.

      c. The bottom surface of the loading block will be no more than 10 mm above the test supports when placed on the load point.

FINAL EVALUATION:

1. Bridges will be registered in the University of Cincinnati High School Bridge Building Competition.
2. Bridges will be assessed prior to the testing to determine if they meet the above specifications.
3. Test #1.

   a. The bridge will be inclined by placing a 50 mm high block under one end of the bridge.

   b. The model car will be placed on the elevated end of the road surface and allowed to roll down its length and exit the bridge. If the car gets stuck, the students may restart from that point. Two restarts will be allowed.

   c. The event supervisors will supply the model car, however the students may bring their own.

4. Test #2

   a. The bridge will be centered on the testing apparatus containing the 350 mm opening between the supports.

   b. The loading block will be applied to the bridge.

   c. A rod ¼” in diameter will be attached to the loading block, which will be used to apply force to the loading block.

   d. The test will be stopped when the applied force reaches a maximum and begins to decrease or the maximum vertical deflection reaches 25 mm.

5. Evaluation of Test Results
   1. Bridges are to be designed to maximize strength and stiffness while minimizing weight. See UC Bridge Competition information for scoring details and awards.

DESIGN PROCESS & TESTING REQUIREMENTS:

1. Your procedure must not involve any sort of safety hazard. Your procedure must not involve any safety hazard. Goggles must be worn during testing. Goggles and adult supervision are required while tools are being used.
2. A project proposal must be approved and signed by the teacher before construction begins.
3. Quantitative tests (strength of materials, strength of joints, etc.) must be used to inform decisions made (choice of materials, assembly, etc.) during the design process. These must be documented in the report.
4. Unless all testing data and the final evaluation are perfect (not likely), evidence must be shown that design changes were made based on quantitative tests.

REPORT:

Reports will be evaluated according to the following criteria:

Presentation of Physical Concepts

· Introduced the relevant physical principles (and historical background when appropriate) completely and clearly

· Kinematics and dynamics accurately represented throughout (symbols, graphs, text, data, equations)

· Accurately described/defined relevant quantities (d, v, a, F, etc.)

Design Process and Analysis

· Demonstrated careful and thorough planning

· Quantitative tests conducted during the design process

· Quantitative tests used to inform decisions made during the design process

· Used a logical method to effectively manipulate materials during design/construction

· Used a logical method to effectively manipulate materials and instruments during testing

· Interpreted/analyzed data logically and correctly

Communication

· Submitted a formal report containing all the required sections

· Submitted an attractively formatted, completely word-processed lab report

· Electronically inserted a picture or diagram into the report

· Presented and organized data in table (and graph, where appropriate) form

· Data collection/reporting was accurate and complete

· Showed complete quantities with units

· Presented information and analysis in an easy-to-follow format and writing style

· Gave a clear interpretation/analysis of test and data

· Clearly states the purpose of the work

· Proposed an appropriate and succinct concluding evaluation

· Followed rules of grammar, sentence construction, and punctuation; minimum of spelling errors

Teamwork and Cooperation

· Met intermediate deadlines set by the teacher; came to class prepared, used class time effectively

· All members were helpful and respectful to each other

· All members participated and made a significant input

 

2004 Competition Picture Gallery