Bridge Bash

I.  Purpose:

To increase awareness of careers in Engineering and encourage technical achievement among future Engineering students.

II.  Objective:

This Structural Engineering event provides an opportunity for students to demonstrate their ability to produce a model that will be destructively tested in order to determine efficiency. Weight will be applied to the completed bridge until it breaks or until the breaking apparatus reaches its maximum limit.  The bridge weight and breaking weight will be put into a formula that will determine the efficiency of the bridge.  Awards will be given to students who have the highest efficiency within their bracket (Middle School, or High School).

III.  Official Specifications and Rules:

IN ORDER TO OFFICIALLY PARTICIPATE,  ALL BRIDGE STRUCTURES MUST MEET THE FOLLOWING QUALIFICATION REQUIREMENTS.

      A.         All BALSA wood must be provided by TAME in kit form(16 sticks per kit).  You can not use any other type of wood and the maximum weight of the completed bridge can not  exceed 60 grams.  Only the 1/8" X 1/8" BALSA wood supplied in the kits may be used and it cannot be treated,  coated, or painted.   You must supply your own glue and all excess glue must be removed from around the joints and other parts of the bridge.  You may use all  the material provided in your kit; however, keep in mind that the weight of your bridge plays a big part in determining efficiency and can hurt you if it is too great. 

      B.         Pins, tape, string, paper, or any other materials used in the construction of the bridge must be removed before the bridge is registered.  Remove all excess glue and paper around the joints. 

      C.        The bridge must not exceed the following minimum and or maximum dimensions

1. Overall length-minimum of 22 inches, maximum of 24 inches.

2. Span must be a minimum of 20 inches long; therefore, overall length of sub-structure can only be 19 inches maximum with a 3 inch maximum depth.

3. Roadbed or width- minimum of 3 inches, maximum of 6 inches and cannot exceed a maximum height of 1/4 inch above road surface.

4. Overall height of combined roadbed and super-structure- 3 1/4 inches minimum to a  maximum of 15 inches high.

5. Bridges must be built in order to accommodate the test block  and hook at the center of the roadbed.   The sub-structure  must also be designed so that it can not utilize the bridge support system for added support during testing.

IV.  Definitions and Efficiency Formula

A. Definitions

1. Span- Distance between bridge supports

2. Sub-structure- The structure that extends below the roadbed

3. Roadbed- The part of the bridge that is normally traveled upon and on which the test block will be placed.

4. Super-structure- The structure that extends above the roadbed

B. Efficiency formula

Load (in lbs.) X 4.45 = Failure Weight

EFFICIENCY (E) =           ^{Failure Weight  
                                                                                 Weight of Structure (grams)}

NOTE: ALL BRIDGES MUST BE REGISTERED BY 10:30 A.M., IF THEY ARE TO BE ENTERED IN THE COMPETITION.