NEWS from Southwest MS Resource Conservation & Development (RC&D), Inc.

PO Box 3670 Brookhaven, MS 39603-7670

601-833-5539 Fax 601-835-0054 E-mail southwest@msrcd.org

For more information contact Bennie F. Hutchins, RC&D Coordinator

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12TH NATIONAL TIMBER BRIDGE DESIGN COMPETITION

RESULTS ANNOUNCED

Fourteen 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, Wood Protection Products, Inc., 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 www.msrcd.org

Winner of the Best Overall Design Award sponsored by Weyerhaeuser Company was University of Texas at San Antonio ASCE. Their design consisted of a transverse 2" x 4" deck supported by five longitudinal beams working with a half-through arch at each curb. The laminated arches each had five 1/4-inch suspension rods supporting the outside beams. This entry also placed second in Best Deck, judged by performance (deflection), weight, percent nonwood, practicality, innovation and aesthetics. The team received cash awards totaling $1,250 for their efforts, making it the top money-winner also.

The second place money winner was Clarkson University ASCE, taking home $1,050 in prizes. Their entry placed first in Most Innovative Design, second in Best Overall Design and third in Most Aesthetic. Their bridge support structure was two box girders designed with an internal cable truss system of two 9.5 mm steel cables placed between each girder's three webs.

Other first place awards went to University of Wisconsin-Platteville ASCE for Most Practical Design, to State University of New York-Environmental Science and Forestry FPS for Most Aesthetic Design, to Mississippi State University ASCE for Best Support Structure, and to Washington University at St. Louis ASCE for Best Deck. SUNY-ESF Forest Products Society Chapter also placed second in Most Innovative, taking $650 in awards, along with Washington University at St. Louis and Mississippi State University.

San Francisco State University ASCE was the third highest money-winner, receiving $725 for second place in Best Support Structure, third in Best Overall Design and third in Most Innovative Design. Their bridge featured epoxy resin glue and carbon fiber at all joints to maximize stiffness, use of Brazillian Ipe wood in the two parallel trusses due to its density and resistance to decay, and Simpson Skidguard coated 3/4-inch plywood decking.

Other entries receiving awards were University of Wyoming ASCE for third in both Best Overall Design and Best Support Structure, Ohio State University ASCE for second in Most Aesthetic and third in Best Deck, U.S. Military Academy ASCE for second in Most Practical Design, and University of Massachusetts-Amherst for third in Most Practical Design.

The test bridges were 13.1 feet (4.0m) long and 4.3 feet (1.3m) wide and were loaded with a test weight of approximately 4,500 pounds. Average weight of the bridge models was 856 pounds (389 kg). At full loading, maximum bridge deflection ranged from 2.39mm to 9.91mm. Maximum allowable deflection was 10.0mm. Percent non-wood materials in the bridges averaged 7.6%; maximum percent non-wood materials allowed was 25 percent, by weight.

For a complete review of 2004 Competition Results and each individual entry including drawings and photos, go to www.msrcd.org/bridge.htm and select from menu. Results of 1998-2003 competitions are also posted online. Rules for the 2005 competition will be the same as 2003 and are already posted online. For additional information contact Southwest Mississippi RC&D, Inc., competition coordinator, at southwest@msrcd.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.

Judges for the competition were Scott Groenier, P.E., National Wood in Transportation Program, USDA-Forest Service, and Dr. Rakesh Gupta and his Wood Engineering class at Oregon State University.