May 03, 2002 09:00 ET|
Southwest MSRCD Announces 10th Annual Timber Bridge Competition Results
BROOKHAVEN, MS--(May 03, 2002) - Southwest Mississippi Resource Conservation and Development Council, Inc. today announced the results of it's 10th annual National Timber Bridge Competition.
Sixteen teams of students from universities across the US matched wits in the recently completed National Timber Bridge Design Competition. Open to student chapters of American Society of Civil Engineers (ASCE) and Forest Products Society (FPS), the competition was made possible by a grant from the US Forest Service through its Wood In Transportation Program. Additional financial support was provided by the Southern Pine Council of the Southern Forest Products Association, Unit Structures LLC, and Weyerhaeuser Company. Southwest Mississippi Resource Conservation and Development (RC&D), Inc., coordinates the annual competition.
Each team designed, constructed and tested their bridges on their home campus, then submitted documentation of their activities and results to a panel of judges for review. The competition is conducted online via the Internet. Each team is required to post design drawings, test results, and project highlights on the Web at http://southwest.msrcd.org/timberbridge. Click on "2002 Competition Results" to view complete details of competition results and to access each entry in its entirety.
Winner of the Best Overall Design Award sponsored by Weyerhaeuser Company was Virginia Tech FPS Chapter. Their design used 2 two-dimensional, moment-resisting trusses positioned at outside curbs with ledger beams supporting 5/4-inch thick transverse deck boards. A 2 x 8 stringer added additional support down the bridge center. All wood members were CCA-treated southern yellow pine, with trusses joined by resorcinol phenolformaldehyde adhesive. This entry also placed second in Best Support Structure. The team received cash awards totaling $2,250 for their efforts.
The second place money winner was University of Missouri-Rolla ASCE Chapter with awards totaling $2,000. Their entry placed first in Best Support Structure and second in Best Overall Design. Their design featured two above-deck trusses at each curb supporting a deck designed to act as multi-celled box beams at the positive and negative moment regions and as T-beams near the areas of contra-flexure. The deck was built in two sections, a concept allowing one traffic lane to be replaced while the other remains open.
The Rose-Hulman Institute of Technology ASCE Chapter was another big winner, receiving $1,500 for first place in Most Aesthetic Design, second in Best Deck and third in Best Support Structure. Their twin-arch suspension bridge used 2-inch T&G deck placed diagonally over a system of 2 x 8 girders and 2 x 4 transverse joists. Unique tension connections between chords and arches took advantage of the natural tensile strength of wood.
The Best Deck first place award went to University of Alabama at Birmingham ASCE Chapter for their CCA-treated southern yellow pine longitudinal deck of 2 x 4s on 2 x 6 transverse beams, all supported by 2 outside trusses. The entry also received third place in Most Practical Design. A second team from UAB placed second in Most Practical Design.
The Most Innovative Design was submitted by the U.S. Military Academy ASCE Chapter, fully illustrating the viability of timber in an innovative design and demonstrating the compression strength and sleek design potential of timber. Two arches supported a transverse beam-longitudinal deck design in suspension and compression. Their entry also received third place in the Most Aesthetic category.
The final first place award went to Clarkson University for Most Practical Design. Their variation of through truss design allowed the use of smaller members that can be fabricated from lumber species and grades that have a relatively low modulus of elasticity.
Other teams capturing top-three awards were Cal State-Fresno ASCE (second in Most Aesthetic and third in Most Innovative), University of New Hampshire ASCE (second in Most Innovative), San Francisco State University ASCE (third in Best Deck), and Mississippi State University ASCE (third in Best Overall Design).
Other teams competing were State University of New York – College of Environmental Science and Forestry FPS Chapter and ASCE Chapters from Clemson University, Washington University in St. Louis, University of Louisiana at Lafayette, and Oklahoma State University.
For a complete review of Competition Results and each individual entry, go to http://southwest.msrcd.org/timberbridge and follow links. Results of 1998-2001 competitions are also posted online. Rules for the 2003 competition will be posted online by mid-August 2002. For additional information contact Southwest Mississippi RC&D, Inc., competition coordinators at firstname.lastname@example.org.
The competition's objectives are to promote interest in the use of wood as a competitive bridge construction material, to generate innovative and cost-effective timber bridge design techniques, and to develop an appreciation of the engineering capabilities of wood among future transportation and forest products engineers. Following the competition, most of the bridges were placed into use as trail bridges.
The test bridges were 11.8 feet (3.6m) long and 4.6 feet (1.4m) wide and were loaded with a test weight of approximately 4,500 pounds. Average weight of the bridge models was 683 pounds. At full loading, maximum bridge deflection ranged from 1.39mm to 8.67mm. Maximum allowable deflection was 9 mm. Percent non-wood materials in the bridges averaged 5.3%; maximum percent non-wood materials allowed was 25 percent, by weight. A total of 111 students spent 3,360 hours on the competition, competing for $10,000 in prizes. Judges were Bobby Briggs, Weyerhaeuser Company; Scott Groenier, USDA Forest Service; and Chad Fowler, Unit Structures LLC.
Bennie F. Hutchins