Society of Manufacturing Engineers

Northern Piedmont Chapter 082

http://chapters.sme.org/082/

Requests your participation in our Middle & High School

National Engineers’ Week

2006 Popsicle Stick-Bridge Contest

 

Objective - To build the strongest bridge from Popsicle Sticks and white glue to these rules.

 

 The Awards are 1st - $100, 2nd - $50, 3rd - $25, One set for High School & one set for Middle School.

 

RULES:

1. The bridge is to be built from Popsicle Sticks 1/16” x 3/8” x 4 ½” and water-soluble white glue, such as Elmer’s “Glue-All” or “Tacky”.  Bridges using other than these materials and the loading platform materials will be disqualified. Painting or decorating the bridge is not permissible.

 

2. The bridge shall be freestanding and must span two level surfaces, which are 24” apart and 4” wide.  The ends of the bridge must extend at least 3” on each end past the span opening and be 4” or less in width.  The bridge will be about 30” total length.

 

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

 

4. The bridge must include a decking of Popsicle sticks to provide a suitable road surface at least 2” wide across the full span of the bridge. Three conditions must be met:

a) Gaps in the bridge deck are not to exceed 1/16”.

b) A block of wood 2” x 2” x 4” representing a car must be able to move along the length of the decking unobstructed from end to end,

c) The deck of the bridge must not be more than 3” above or below the ends of the bridge at any point along its length.

 

5. You must incorporate a "loading platform" consisting of a 1½” U-bolt secured to a piece of plywood 1/4” x 2” x 4.5” max. This platform is to be attached at the center of the bridge such that the bottom of the U-bolt is no more than 2” from the top of the bridge decking. All loads will be suspended from this U-bolt, and there must be a clear space directly below it to allow loads to be attached. Loads will be attached using an S-hook & chain.

 

6. The maximum vertical height of the bridge, from the highest point in its structure to the lowest cannot exceed 8”.

 

7. The maximum weight of the bridge including the loading platform must not exceed 500 Grams.

 


8.  The bridge will be hydraulically loaded at mid-span until a maximum load has been determined.  That amount will be divided by the total bridge weight before testing. Bridges at maximum load may not always fall apart.  The higher the ratio the better the strength to weight ratio.  Highest ratio wins!  Example 200 p.s.i / 500 grams = 0.4, or 200 p.s.i. / 300 grams = 0.67