Overview - Each student will enter a Paper Bridge and Full Scale Drawing with Force Analysis Poster to compete in Physics Olympics.  Each student is to complete his or her project according the design requirements and due dates. Students may bring their project to class prior to competition day for approval and inspection by his or her teacher as well as to check their project for minimum supporting mass requirements.

Purpose - To construct a bridge from paper and glue that will support the heaviest load (minimum supporting mass requirment is 5 kilograms).

ATTENTION PARENTS AND STUDENTS

The bridge project requires the fabrication of bridge components which may require the use of hand or power tools. Common tools used are scissors, knife, electric drill and handsaw or power saw. Follow all manufacture safety guidelines and directions including the use of safety goggles. Tools should be used under adult supervision. The bridge project requires the fabrication of bridge components which may require the use of white glue. Follow all manufacture safety guidelines and directions.

CHECK BEFORE YOU START!
	Check with your teacher for any special allowances or exceptions before you begin designing and constructing your bridge.

Requirements
1. The bridge is to be constructed from white 8.5" X 11" or 8.5" X 14" computer/zerox paper
NO OTHER PAPER PRODUCTS ARE ALLOWED.

2. ONLY Elmer's glue (generic white glue) or Elmer's glue stick (generic glue stick) are allowed. Paper mache' is NOT allowed.
NOTE - White glue will not discolor or change the opaque characteristic of the paper. Any white glue or glue stick that discolors the paper is NOT allowed.

3. Tape of ANY type is NOT allowed except in the construction of bridge members as explained in the member and joint construction worksheet/link.

Allowed Glues

Only white paper is allowed. The pictures below use colored paper to more clearly illustrate the different methods of joint construction.

ONLY WOOD TOOTPICKS ARE ALLOWED.

Butt Joint
Two rolled members butted together and secured with an outer sleeve (green). The outer green sleeve and two inner members are secured together by four pins (wood toothpicks). There are two pins per inner member. Both members are under tension. The members are being pulled away from each other. One toothpick has been left extending beyond the sleeve to clearly illustrate the construction method. All toothpicks should be trimmed close to the sleeve.

Bent Butt Joint
Two rolled members secured with an outer sleeve (green) and bent to form a corner. The outer green sleeve and inner member are secured together by two pins (wood toothpicks). Only the lower member is pinned. The lower member is under tension while the upper member is in compression. Only the tension member needs to be pinned. The tension member is pulled away from the joint and the compression member is pushed towards the joint. Pin orientation is important.

Slip Tube (Tongue) Joint
One rolled member with an outer sleeve secured and extending beyond the end of the inner member. The outer green sleeve and inner member are secured together by two pins (wood toothpicks). The portion of the sleeve extending beyond the inner tuber is flattened. The flattened portion can be bent or wrapped around other members. The pinned member is under tension.

5. Glue restrictions and usages are as follows:
Allowed:
- Glue may be used to laminate sheets of paper together.
- Glue may be used to bond 2 or more members together.
- Glue may be used to bond the roadway to support members.
Disallowed:
- No more than 50% of the bridge's truss surface area and roadway may be covered/coated in glue.
- No facades may be used to hide excessive glue.

6. Member bonding restrictions are as follows:
- Glue used for the purpose of bonding two of more skew or perpendicular members together.may not extended more than 2 cm beyond the joint.
- There is no member bonding restriction for the joining of parallel members.

Member Construction

Butt Members

• Cut a piece of paper in half lengthwise. (Save the other half for the Slip Tube instructions.)
• Place 3 small pieces of tape (2 cm) along the edge of the table.
• Using a pair of scissors cut “tube #1” in half making sure to the cut along the middle of the center piece of tape.
• Measure and place a mark 6 cm from the UNCUT ends of the both tubes.
• Butt the uncut ends together. Center the cut piece of paper between the marks and wrap the piece of paper around the tubes lengthwise.
• Roll the tube away from yourself while applying a gentle downward force on the tube.
• Reposition the tube and your hands once the tube has rolled to the bottom of your palms.
• Repeat until the newly wrap tube is tightly wrapped around the butted tubes.
• Securely place three pieces of tape along the rolled edge the paper. Place two pieces very close to each end of the tube. Place one piece in the very center of the tube.

Slip Tube

• Find the saved half of lengthwise cut paper (see above).
• Place 3 small pieces of tape (2 cm) along the edge of the table.
• Measure and place a mark 6 cm from one end of “tube #2”.
• Center the cut piece of paper along the tube and wrap the piece of paper around the tube lengthwise.
• Roll the tube away from yourself while applying a gentle downward force on the tube.
• Reposition the tube and your hands once the tube has rolled to the bottom of your palms.
• Repeat until the newly wrap tube is tightly wrapped around the tube.
• Securely place three pieces of tape along the rolled edge the paper. Place two pieces very close to each end of the tube. Place one piece in the very center of the tube.
• Slide the newly wrapped tube towards the end with the mark. Continue sliding the newly wrapped tube until the mark has passed completely beneath the tube and appears on the other side.
• Approximately 5 cm of the newly wrapped tube should extend beyond the end of “tube #2”.
• Carefully flatten the extending end making sure not to damage to tube beneath the 6 cm of overlap.
  

7. The bridge shall be free-standing and must SPAN two level surfaces which are half a meter apart. It is recommended that the minimum length of the bridge be no less than 54 cm.

8. The bridge MUST incorporate a truss design. Students MAY select one of the basic truss designs illustrated below or DESIGN THEIR OWN unique truss design. If a student selects to design their own unique truss design, it is recommended that the design be reviewed by his/her teacher. NO inverted bridges (trusses are beneath the roadway).

Bowstring	Camelback	Howe
Pratt	Waddell "A"	Warren

9. All students are REQUIRED to use the bridge design simulation shown below. For the bridge design simulation, Click here.

10.The support for the bridge shall be from the top of the level surface. The edges of the level surface cannot be used in any way for support.

ACCEPTABLE (table provides only vertical support)	UNACCEPTABLE (table is providing horizontal support)

11. The bridge must include a decking of paper to provide a suitable road surface at least 5-cm wide across the full span of the bridge. Four conditions must be met:
- The deck may not have any gaps.
- A block of wood 5-cm x 5-cm x 1-cm representing a car must be able to move along the length of the deck unobstructed from end to end.
- The highest point of the deck may be no higher than 5 cm above the tabletop to allow for loading zone reinforcement.
- The deck of the bridge must either be flat across its entire span or inclined upwards towards the loading zone.

Key to Loading Zone Construction

Finally, consider reinforcing the loading zone. A poorly designed and reinforced loading zone may result in structural failure ONLY at the loading zone. This unfortunate over site may leave the rest of the bridge structurally intact. Loading zone reinforcement should not be limited to excess use of glue but may include the construction of additional members (i.e. layers and/or joint construction). Remember the entire weight supported by the bridge is applied at the loading zone. What will work best for you? Experiment and find out!

12. You must incorporate a "loading zone" at the midpoint of the span along the centerline of the bridge. The loading zone must be 5-cm x 5-cm and receive a flat block of wood called the loading platform. A half-inch hole must be located at the center of the loading zone and pass completely through the deck and all bridge supports beneath the deck. A bolt will be inserted through the hole from beneath the deck and attached to the loading platform. Your instructor will provide the bolt and loading platform.

13. The maximum vertical height of the bridge, from the highest point in the structure to the lowest point, cannot exceed 30-cm.

14. The MASS of the bridge shall not exceed HALF A KILOGRAM.

15. The bridge may not be COLORED in any fashion (paints, canyons, markers, etc.). The color of the bridge may reflect the color of the paper and tape/glue used.

16. Failure to meet these specifications will result in grade penalities. See grading rubric for details.

Helpful Hints
— How Stuff Works
— Force Lab
— ABC's of Bridge Design
— Topics on Bridge Construction

Bridge Testing
1. The load will be applied on the roadway surface at the mid-span along the centerline of the bridge by means of a loading platform.
2. A mass cradle will be attached to the loading platform and be suspended below the bridge.
3. Mass will be loaded into the mass cradle until structural failure is reached.
4. The final grade will be determined by the greatest mass held without partial or complete structural failure. Refer to the bridge rubric for details.

Poster - Simulation - Grading

This activity may be reproduced in any form for use in a classroom, but under no
circumstances may any portion be reproduced for publication without written consent.