May 04, 2001 09:00 ET|
Southwest MSRCD Announces 9th Annual Timber Bridge Competition Results
BROOKHAVEN, MS--(May 04, 2001) - Southwest Mississippi Resource Conservation and Development Council, Inc. today announced the results of it's 9th annual National Timber Bridge Competition.
Nine 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 Willamette Industries. 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 "2001 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 Willamette Industries was Mississippi State University ASCE Chapter. Their design used multiple members in both tension and compression to minimize weight and deflection. A 1" x 4" T&G deck was supported by 7 glue-laminated longitudinal stringers. Four steel cable assemblies were added to limit tension in the bridge. All wood members were southern yellow pine treated with bromated copper arsenate at 0.40 pounds per cu. ft. This entry also placed second in Best Deck Performance and second in Most Aesthetic Design. The team received cash awards totaling $2,350 for their efforts.
Top money winner was United States Military Academy ASCE Chapter with awards totaling $2,500. Their entry placed first in Best Deck Performance and Most Practical Design while winning second place in Best Support Structure Performance and The Willamette Industries Best Design. Their design featured a transverse deck of 2" x 6" CCA-treated southern yellow pine ship-lapped and edge-glued. The deck was supported by 3 longitudinal parallel trusses built of SYP 2 x 4s using standard nail plates. Their goal was practicality and speed of construction, combined with strength and light-weight.
The ASCE Chapter of Washington University at St. Louis was another big winner, receiving $2,000 for first place in Best Support Structure Performance, second in Most Practical Design and third places in Best Design and Best Deck Performance. Their twin composite I-beam structure used CCA-treated SYPine with eight 2" x 6" transverse stiffeners spanned by a longitudinal deck of SYPine 2" x 6" planks.
The final first-place entry was produced by San Jose State University's ASCE Chapter. Their above-deck parallel-chord trusses combined with longitudinal 2" x 6" Douglas fir deck caught the eyes of all three judges to win first place as Most Aesthetic. Adding two third place awards in Most Practical Design and Best Support Structure brought their total awards to $1,350.
Virginia Tech's Forest Products Society Chapter was the only other first place winner, capturing Most Innovative Design for their arch-suspension bridge. Clarkson University and Oklahoma State settled for a second place tie in this category. Other teams competing included Merrimack College ASCE and Rose-Hulman Institute of Technology ASCE.
For a complete review of Competition Results and each individual entry, go to http://southwest.msrcd.org/timberbridge and follow links. Results of 2000, 1999 and 1998 competitions are also posted online. Rules for the 2002 competition will be posted online by mid-August 2001. 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 for pedestrians, horses, snow mobiles, etc.
The test bridges were 13 feet long and 4 feet wide and were loaded with a test weight of approximately 4,500 pounds. Average weight of the bridge models was 722 pounds. At full loading, maximum bridge deflection ranged from 4.42 mm to 9.91 mm. Maximum allowable deflection was 10 mm. Net deck deflection for the three bridges that met the maximum allowable deflection of deck span divided by 400 averaged 74% of maximum allowable. Percent non-wood materials in the bridges averaged 8.5%; maximum percent non-wood materials allowed was 25 percent, by weight. A total of 68 students spent 1,583 hours on the competition, competing for $10,000 in prizes. Judges were Bert Lovell, Willamette Industries; Nelson Hernandez, USDA Forest Service; and Shannon McCarty, USDA-Natural Resources Conservation Service.
Bennie F. Hutchins