The Bridge Competition: The Bridge Competition


Agenda: Agenda Introduce concepts of bridge structures Introduce Bridge Competition Assignment Description


What is a bridge?: What is a bridge? A bridge is a structure that spans a divide such as: A stream Railroad track The traffic that uses a bridge may be limited to: Pedestrian or cycle traffic Vehicular or rail traffic A combination of all the above


Bridge Components: Bridge Components Deck Pier Span Abutment


Bridge types: Bridge types Girder Truss Rigid Frame


Bridge types (continued): Bridge types (continued) Arch Cable Stayed Suspension


Essential Elements of a Bridge: Essential Elements of a Bridge Stability: subcomponents should not move excessively Strength: members should be able to withstand applied forces


Stability Examples: Stability Examples Stable structures Unstable structures


Forces in a simple Truss: Forces in a simple Truss Tensile forces tend to lengthen a member Compressive forces tend to shorten or compress a member


Common Forms of Failure: Common Forms of Failure Buckling or crushing for members in compression Pulling apart in the middle for members in tension Pulling apart at the joints


Project Description Handout: Project Description Handout Assignment Materials Testing Procedure Grading Criteria Report Requirements Timeline Construction Hints


Assignment: Assignment Construct a balsawood bridge using the approved materials according to the competition rules Compose a lab memo See project description for further information on contents and point distribution for the memo


Materials Supplied: Materials Supplied 4 No. 3/16”x3/16”x36” balsa wood 4 No. 1/8”x1/8”x36” balsa wood 1 No. 1/16”x3”x36” balsa wood 1 No. Light Duty Hobby precision knife 1 No. sheet 400 gauge SA4 sanding paper 1 No. 4Fl. Oz Elmer’s Glue Will be supplied in the Team Building Workshop!


Some examples of past bridges…: Some examples of past bridges…


Some examples of past bridges…: Some examples of past bridges…


Some examples of past bridges…: Some examples of past bridges…


Some examples of past bridges…: Some examples of past bridges…


Some examples of past bridges…: Some examples of past bridges…


Bridge Testing Procedure: Bridge Testing Procedure Please note the Bridge Testing procedure outlined here: Inspection of Bridges 15 minute period for making amendments Weigh-in and submission of Bridges Testing to failure


Bridge Testing Apparatus: Bridge Testing Apparatus


Grade Assessment Criteria: Grade Assessment Criteria The grade is based in part on: Balsawood Bridge Use of approved materials Aesthetics Strength to weight ratio Memo Description of the team dynamic in respect to this project Design description and suggestions on how the bridge could have been improved within the context of the competition rules


References: References Balsawood Competitions Physics Balsa Wood Bridge Competition (lots of reference links) Ocean Community College’s Bridge Competition Bridge Sites How Bridges Work Balsawood Construction Information ABCD's Bridge Design Tips


Assignment: Assignment Create balsawood bridge and present the final model for the Bridge Competition to be held during Lab 4. Prepare a report memo due at the beginning of Lab 5 which includes a Team Working Agreement (see workshop handout for details) Read all bridge materials and be prepared to discuss possible ideas in the Team Building Workshop.