BRIDGE BUILDING

Bridges are structures that carry people and vehicles across natural or man-made obstacles. There are many types of bridges. Based on the length of the barrier to be crossed, the amount and type of traffic as well as forces of nature, different materials and shapes of bridges are used. You and your partner(s) will be designing a bridge with a specific challenge. Enclosed in this booklet is all you need to know about the BRIDGE CHALLENGE!

Names of group members: ______

Your challenge is to build the lightest bridge that can hold the greatest load. But there are specific instructions that your group must follow:

  • The first 5 minutes of every class will be a check in time to discuss any problems and receive instructions and goals for the class period.
  • When check in time is complete you will be allowed to collect your materials and begin working on your bridge project.

How you will be assessed.

  • Task Management – Each day during the project you will earn a score from 0 to 4; ranging from no work done/constant distraction to excellent. Points will be lost for off task behaviors. You will receive 0 points for the day if your behavior results in dismissal from class or you are absent. Scores of 0 for absences may be made up at alternate times offered. Daily scores will be averaged and count towards 30% of your overall project grade.
  • Bridge Journal – Each week during the project a journal entry must be written. Each partner will be responsible for an entry every other week. The entry will have guiding questions to answer. Each entry must be at least 8 meaningful sentences long and completed by the due date assigned. The weekly scores from 0 to 4 will be averaged and count towards 20% of your grade.
  • Blueprints. You will design your bridge prior to building it. This is to prevent material waste and help guide the construction process. You will create two blueprints labeled side and roadbed view. A draft of the side view will be done first; the roadbed view is to be completed after it has been built. Lines must be straight! (RULER) You must indicate the dimensions: Length, width and/or height on the blueprint. Your final blueprint must be neat and outlined, worth 25% of grade.

Example: Side View

  • Bridge Construction. You will be provided with the following materials; 13 pieces of 1/8 x 1/8 inch balsa wood, wax paper, glue and masking tape.
  1. Criteria for bridge – 25% of grade
  • The bridge must span at least 30 cm.
  • The bridge must be 5 - 6 cm wide.
  • There is no height limit to the bridge.
  • You are not allowed to split or laminate the balsa wood.
  • Wood may only be bonded with glue at the joints.
  • Bridge must also have an opening in the center of the roadway for testing that is less than 5 cm wide and is easily accessible for the loading block. Model below:

  • Competition.On the day of the competition you will need to hand in yourfinal blueprints, this Bridge building packet, and rubric.
  • You will then mass your bridge and record in the scoring section below.
  • When your group is called you will center your bridge on the tests supports that contain the 30 cm opening.
  • You will then place the loading block with eyebolt in the center of the bridge.
  • A container will be suspended from the eyebolt.
  • Wearing safety goggles you will have a maximum of 10 minutes to add the sand. If the time expires, the bridge will be scored using the mass of the sand that has been loaded when the time expires.
  • You will add sand to the bucket until failure occurs. Failure is defined as the inability of the bridge to carry additional load or when any part of the bridge extends more than 2 cm below the top of the test supports.
  • The mass of the loading block, eyebolt, washer, wing nut, bucket, and sand are included in the Load Supported.
  • The score will be determined by the structural Efficiency equation:

Structural Efficiency = Load Supported (g) / Mass of Bridge (g)

Scoring

Mass of Bridge (g):______

Load Supported (g):______

Structural Efficiency (%): ______

Name:______Period:_____

BRIDGE BUILDING RUBRIC

Excellent (4) / Good (3) / Fair (2) / Unacceptable (1) / Missing (0) / Points Earned
Task Management
30% / Student remained on task for the entire project
(30) / Student remained on task at least 80% of the time
(24 - 29) / Student remained on task at least 70% of the time
(21 - 23) / Student remained on task less than 70% of the time
(15 - 20) / Student was absent or dismissed from class too often.
(0 - 8)
Blueprints
Drawings
25% / Blueprint of both views are neat and include labels and dimensions.
(25) / Blueprints include at least 80% of the required elements.
(20 - 24) / Blueprints include at least 70% of the required elements.
(17 - 19) / Blueprints include less than 70% of the requirements.
(13 - 16) / Final Blueprints are missing.
(0 - 6)
Bridge
Construction
25% / Bridge follows blueprints with no laminating or splitting of wood and meets the width (5-6cm) and span requirements (>30cm)
(25) / Bridge construction meets 80% of the required elements.
(20 -24) / Bridge construction meets 70% of the required elements.
(17 - 19) / Bridge construction meets less than 70% of the required elements.
(13 - 16) / Bridge construction not completed or meets less than 50% required elements.
(0 - 6)
Journal
20% / Journal entries are completed on time, have at least 8 meaningful sentences each, and follow RAPS
(20) / Journal entries meet 80% of the required elements and/or are consistently late.
(16 - 19) / Journal entries meet 70% of the required elements and/or are consistently late.
(14-15) / Journal entries meet less than 70% of the required elements and/or are consistently late.
(10-13) / Journal entries are not completed or missing more than half required.
(0-5)

Total Score: ______