Embedded Files
RICHARDTON HIGH SCHOOL TECHNOLOGY DEPARTMENT RICHARDTON, NORTH DAKOTA
STRUCTURAL ENGINEERING – Bridge Design
OBJECTIVE:
To learn that the scientific method is not a linear process.
To learn the difference between potential and kinetic energy. To learn to use different forces of prime movers.
To learn the principles of forces like compression, torsion, strain, and shear.
Learn the principles of friction, in particular rolling friction.
To work independently or cooperatively. To learn to brainstorm (lens smashing) and develop problem solving skills. Make decisions using trial and error. Work within a given amount of time. Work with only materials given. Deal with competition with your peers.
OVERVIEW:
Participants design and construct a model structure that is destructively tested to determine design efficiency.
CONTEST PURPOSE
The purpose of the Structural Engineering Contest is to provide a means for using TSA rules to demonstrate their ability to design and fabricate a structure after having been assigned span and width specifications.
LIMITATIONS:
SPECIFIC REGULATIONS:
Bridges must be constructed according to specifications and only utilize 1/8” x 1/8” balsa. Bridges must be constructed according to the following definitions and graphic illustrations which are an integral part of the contest regulations.
BRIDGE LENGTH: The overall length of the bridge may not exceed 14” (span + 1” minimum, 2” maximum). All bridges must be between 12”-14” long.
SUPER-STRUCTURE: The structure of the bridge which extends above the roadbed. The maximum width of the super-structure is 5 inches.
SUB-STRUCTURE: The structure of the bridge which extends below the roadbed. The substructure may be no longer than 9”, 3” tall, and 5” wide, and must be centered crosswise under the roadbed.
SPAN: The distance between bridge supports (see test stand).
TEST BLOCK: That piece of test apparatus to which the testing rod (1/4” Diameter) is attached to a testing bucket. The test block is approx.1" x 1 1/2" x 6".
ROADBED: The part of the bridge that is meant to be traveled upon. The roadbed must be maintained at a minimum width of 3" inside the supports. The bridge must be constructed to allow the test block and testing rod to pass through the bridge opening on the roadbed from one end to the other. Roadbed will be represented by a length of tissue paper.
FAILURE: Once the test load is placed upon the bridge, failure is determined by when the bridge collapses.
LAMINATION: Two pieces of 1/8" x 1/8" or 3/32” x 3/32” stock glued together surface-to surface with the wood grain running parallel. Refer to the below for examples of correct and incorrect laminations.
Bridges must be constructed in such a manner as to accommodate the test block and rod at the bridge's center. The roadbed of the bridge must be free of obstructions. Coating of laminated beams with glue will not be permitted.
EVALUATION:
CRITERIA FOR JUDGING:
Method to be used with a bridge testing machine. Richardton High School will use water as its measure of weight.
Bridge efficiency shall be determined by the following formula:
Dividing the failure weight (Load) by the bridge weight
The structure will be weighed and the weight entered into the formula as "Weight of Structure (grams)."
The bridge with the highest efficiency number is the winning bridge.
All efficiency ratings shall be calculated to three (3) decimal places. The highest efficiency rating will be the winner. In the event of a tie, the efficiency rating will be calculated to the next decimal point until a winner is decided. An increasing load will be applied to the bridge via the test hook (Diagram C) until the bridge fails. The load will be weighed and the weight entered in the formula as the "Failure Weight
Page updated
Google Sites
Report abuse