The competition will consist of the construction and testing of a model timber bridge on the home site of each team.


The competition is open to all student chapters of American Society of Civil Engineers and Forest Products Society in the United States and Canada. Joint and multiple entries from one school will be accepted.


Each contestant (team) will be required to design, build and test a bridge constructed from wood structural members. The wood used in this project must be from a commercially available species.


All wood members must be treated to AWPA standards for "above ground use". See www.awpa.com for details on ordering publications or click here for Western Wood Preservers Institute site, click on "retentions" at bottom of menu to left, then select preservative type for standards tables .


Design Span: 3.3 meters from center line to center line of supports. The maximum length of an individual piece in any member shall not exceed 1.6 meters. There is no length limitation on built-up and laminated members provided that the individual pieces, including plywood, used in making the member do not exceed the specified maximum length. Maximum width of supporting base plates is 60 mm.

Horizontal and Vertical Clearances: 1.40 m and 0.90 m, respectively (see sketch).

Test Load: 20 kN for 1 hour. (See test setup for location of loading blocks.)

Load Application and Deflection Measurements: Load to be applied at 4 equal increments of 5 kN each. Deflection readings to be collected at each load increment. Then, four deflection readings to be collected at 15-minute intervals during the 1-hour load duration.

Maximum Vertical Bridge Deflection: Maximum allowed bridge deflection is eight (8) mm as recorded at midspan of the longitudinal beam receiving the greatest loading. Subtraction from deflection due to compression of supports will not be allowed.

Maximum Vertical Deck Deflection: Maximum allowed net deck deflection is maximum deck span length ¸400. Deck deflection shall be measured under the centroid of the loading point where the deck is calculated to experience maximum deflection under full loading. Deck deflection shall be adjusted by subtracting the average of the deflections recorded in the two longitudinal beams immediately transverse to each side of the selected loading point. See "Test Setup" sketch for details on placement of the four loading points. Note that the loading points must be moved as a 4-point unit transversely as needed to assure that the above monitored load point (for deck deflection) is over the point where maximum deck deflection is expected.

The selected loading point must be at the deck's weakest point. It must be halfway between any transverse members such as floor beams, deck stiffeners, cross-bracings, diaphragms, etc. that make contact with the deck's underneath surface. It must also be halfway between any adjacent longitudinal support members. Required photographs and drawings of test setup, both from a side and end view, must be adequate to confirm this.

Bridge Deck: The bridge deck does not have to be wood, but note 25% by weight nonwood restriction on total bridge weight. Any material can be used as long as: it is designed to effectively transfer loads at all locations on its surface to the support structure, is not an open grid, can be treated to withstand weather-related deterioration, can withstand repetitive traffic loading and wear, and is capable of supporting the complete 4-load combination moved anywhere on the deck surface. In other words, it must work in real-life application! The maximum length per piece limit (1.6 meters) still applies to deck materials.

Prestressing: Prestressing will be allowed provided it is done 48 hours before testing.

Bridge Weight: Bridge must be weighed before testing and must include all bridge parts forming a part of the bridge as a structural system.

Curb: The curb does not need to resist a force but must be connected to the bridge. The curb may be a part of arch or truss members. Curb material must meet same requirements as Deck except for load-bearing.

Contestants will be required to submit by Mail:

  1. A VHS color video (maximum of 5 minutes) documenting all phases of bridge construction, weighing, loading, and test results at each loading increment and at the 15-minute intervals until the end of the one hour load duration. It is recommended to include within the frame of all video shots a labeling sign stating the significance and sequence of the picture in the testing procedures.

  2. Photographs (ideally 4" x 6" color prints, not color copies)
           a. one side view from above plan of bridge deck
           b. one end view from above plane of bridge deck
           c. one end view of loading setup
           d. one side view of loading setup
           e. one group picture of bridge design team either on the bridge or with bridge in
          foreground f. (optional) no more than 4 pictures of the bridge construction process that show details
              not evident in above completed photos

              Note: In pictures "a, b and e" above, try to avoid background and foreground clutter
              and negatives, be sure to save as an 8" x 10" enlargement may be requested of award winning entries.

  3. Drawings - Mail a hard copy of bridge drawings entered online. Must be in adequate detail to show spacing and size of longitudinal stringers, floor beams, and deck members and must show their relation to selected loading points, especially the selected deck evaluation load point, from both end and side views.

A technical report must be submitted online (via Internet) using templates provided and will include:
  1. Abstracts: Using maximum of 500 words, explain the bridge design concept and explain what was done to optimize stiffness while attempting to minimize weight of the structure. This abstract will weigh heavily on the "Judges" portion of the ranking (20 percent of total score).
  2. Table of all recorded test results of deflection measurements.
  3. An itemized materials list showing weight of each item and total weight of bridge. The total weight of non-wood material must be less than 25% of the total weight of the bridge. Glue is non-wood.
  4. A short summary (max. 500 words) describing the bridge and its behavior under load.
  5. Drawings: Must be adequate to inform judges of design dimensions; should include longitudinal and transverse cross-sections.
           NOTE: Drawings should be sent as e-mail attachments in .gif, .jpg, or other standard file format.

A panel of three independent judges not affiliated with any contestant institutions will select the winners. Entries that do not meet all rules and performance criteria will be disqualified for consideration for Performance Awards but will be eligible to compete for Special Awards and Best Design. No single entry shall be eligible to receive more than three (3) awards.

  1. Willamette Industries Best Overall Design (1st-$1500, 2nd-$1000, 3rd-$500). This award is intended to reward intellectual effort, regardless of how the design meets the performance-related standards. Judged using following points:
    • Design is a configuration of structural elements that can be optimized through normal engineering methods (20%)
    • Design makes efficient use of structural materials (20%)
    • Design is based on structural concepts that have broad applications (20%)
    • Design shows intellectual effort (20%)
    • Judges' Review/Report (20%) (adequate documentation, clarity, neatness, content, abstract, photos, video)
  2. Performance Awards
    a. Best Support Structure (1st-$1000, 2nd-$750, 3rd-$500) Judged based on weighted criteria:
    • Maximum Bridge Deflection 50%
    • Total Bridge Weight 25%
    • Percent Nonwood (total bridge) 15%
    • Practical 5%
    • Economical 5%
    • Innovative 5%

    b. Best Deck Design (1st-$750, 2nd-$500, 3rd-$250) Judged based on weighted criteria:
    • Net Deck Deflection 50%
    • Total Bridge Weight 10%
    • Percent Nonwood (total bridge) 10%
    • Practical 10%
    • Economical 10%
    • Innovative 10%

  3. Special Awards: (Each category: 1st-$500, 2nd-$350, 3rd-$200)
    • Most Practical Design - Design that can be practical to implement in real-life design and construction; low-tech and easy to construct (low materials and labor costs).
    • Most Aesthetic Design
    • Most Innovative Design (In the use of new and non-traditional materials and/or construction methods).


Deadline for online entry (www.msrcd.org) is April 21, 2000. Deadline for receipt of mailed material (video, photographs, and drawings) is also April 21, 2000. Mail to SW Mississippi RC&D, 747 Industrial Park Rd., NE, Brookhaven, MS 39601. Enclose following information with mailed material:

    College or University
    Student Chapter name, address, phone, fax, e-mail
    Faculty advisor
    Contact person.

All materials received by RC&D will become the property of RC&D.


Winners will be announced online by May 5, 2000. In addition, the full entries of all participants will be released online and available for all contestants as well as any Internet user to review. Each can learn from the successes and failures of others! The results will also be publicized through various publications.


Submit questions by e-mail to southwest@msrcd.org, or contact Bennie Hutchins, SW MS RC&D, phone 601-833-5539, fax 601-835-0054. Check Q & A/Updates regularly for valuable competition updates, rules clarifications, etc.

©2017 Mississippi Association of Resource Conservation and Development Councils.
Report errors to: Keith Mazer.