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

_____________________________________________________________________

14TH NATIONAL TIMBER BRIDGE DESIGN COMPETITION

RESULTS ANNOUNCED

Twelve 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 Washington University at St. Louis ASCE. Their design consisted of a longitudinal, vertical-laminated, post-tensioned redwood deck over transverse stringers supported by steel rods suspended from a trapezoidal arch outside each curb. This entry also placed first in Best Deck Design and first in Most Innovative Design. The team received cash awards totaling $1,700 for their efforts, making it the top money winner.

The second highest money winner was one of two teams from Oklahoma State University (ASCE #158), taking home $1,050 in prizes. Their entry took first place in Most Practical Design, third place in Best Overall Design, and second place in Best Deck Design. Their simple 2 x 6 lumber deck laid transversely over three built-up I-beams was the lightest bridge entered in 2006, weighing in at 308 kilograms, and was built with only 4% (by weight) non-wood materials. All wood members were treated to ground-contact specifications using Copper Azole.

Other first-place winners were the second Oklahoma State University team (ASCE #149) taking Best Support Structure and the Forest Products Society team from University of Arkansas at Little Rock capturing Most Aesthetic Design.

Other bridges scoring well were the ASCE entries from University of Texas at San Antonio and United States Military Academy, each receiving $800 in award money. Additional entries in the 2006 Competition included teams from University of Missouri-Columbia, Oregon State University, University of Tennessee at Martin, Ohio University, Ohio State University and Clarkson University.

For a complete review of 2006 Competition Results and each individual entry including drawings and photos, go to www.msrcd.org/bridge.htm and select from menu. Results of 1998-2005 competitions are also posted online. Rules for the 2007 competition will be similar to 2005 Rules that are already posted online. For final 2007 Rules or additional information contact Southwest Mississippi RC&D, Inc., competition coordinator, at southwest@msrcd.org.

The test bridges were 13.1 feet (4.0m) long and 51 inches (1.3m) wide and were loaded with a test weight of approximately 4,500 pounds. Average weight of the bridge models was 1,136 pounds (516 kg). At full loading, maximum bridge deflection ranged from 3.06mm to 9.01mm. Maximum allowable deflection was 10.0mm. Percent non-wood materials in the bridges averaged 8%; maximum percent non-wood materials allowed was 25 percent, by weight.

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., Missoula Technology and Development Center, USDA-Forest Service, and Paul Gilham, P.E., Western Wood Structures, Inc., Tualatin, Oregon.