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I

 Registration:

1.

 Entry forms and fees must be received by February 1, 2007.

2.

 The completed bridge must be checked-in at IUPUI on February 18, 2007.  Bridges will be tested in order received.
II Dimensions: (See Diagrams)
1. Overall length must be greater than 26" but less than 30". (Figure 2)
2. Bridge must be capable of spanning 24". (Figure 2)
3. Maximum bridge height is 8". (Figure 1)
4. Maximum bridge width is 6". (Figure 2)
5. Minimum bridge width is 3".
6. Each individual balsa member shall be 1/8" wide by 1/8" thick.
III Rules:
1. All materials used for the bridge must be BALSA wood, which is readily available from hobby stores.  You will need approximately one sheet that is 3 feet long, 3 or 4 inches wide, 1/8 inch thick and cut into 1/8” members (refer to Section II Dimensions, #6).  NOTE: Be certain to use Balsa wood - not Bass wood.   (You can easily press your thumbnail into Balsa wood because it is soft and light.  Bass wood is harder and heavier).  You will need to use your own glue (see suggestions on Tip Sheet).
2. Loading will be applied at the center span using a block and hook (Figure 3).  All bridges should provide for adequate support of the loading block (Figure 10).  The block and hook will be furnished at the competition.  The block and hook do come apart if they need to be attached to the bridge.
3. Mechanical fasteners will not be permitted.
4. Glue may be placed on the face of the joint being glued and not on the side face (Figure 4).  Joints should not be surrounded by glue.  Glue may not be spread more than 1/4" beyond the glued joint.
5. The bridge may not be painted, coated, or treated in any way.
6. Individual members of the bridge cannot be laminated together (Figure 5). The allowable overlapping of one member to another is ½" (Figure 6). Parallel members may be connected to each other only where they contact cross members (Figure 7) or where spacers are permitted (Figure 12). Minimum spacing between parallel members is 1/8".
7. Bridges are not allowed to butt up against the support (Figure 8).
8. Coping of members for the purpose of making longer members is allowed only if the angle of cope is at least 45° (Figure 9).
9. Emergency balsa wood and glue will be available for repairs the day of the competition.
10. For safety reasons, bring your own safety glasses the day of the competition.  Each team member will be required to wear safety glasses during the testing of the bridge.
IV Judging:
1. Judging of the bridge will be based on an efficiency factor.
2. The bridge will be weighed and impounded until it is loaded.
3. Teams will have 10 minutes to set-up and load their bridges.
  4. The bridge is considered to have failed if it collapses and cannot support any weight, or the bridge deflects 4” or more from horizontal.
5. The efficiency factor is the applied load divided by the weight of the bridge.  The applied load is the load that causes the bridge to fail, or 20kg (44 lbs.), whichever occurs first.
6. The highest efficiency factor will be the winner.