P.O. Box 577
Yosemite, CA 95389
www.nps.gov/yose/news

209 372-0529 phone
209 372-0371 fax

October 24, 2002
For Immediate Release

Yosemite National Park Uses Historic Methods to Restore and Repair Wawona Covered Bridge

Extensive restoration is underway on the Wawona Covered Bridge in Yosemite National Park. The bridge, in the southern portion of the park, is a historical structure listed on the National Register of Historic Places. It is one of two covered bridges located in a national park and one of 13 in the state of California. The original bridge was built by Galen Clark as a truss bridge in 1868 and was later converted to a covered bridge in 1878 by the owners of the Wawona Hotel.

Wawona Covered Bridge and access across the south fork of the Merced River has been temporarily closed for structural repairs. The bridge is in poor condition due to extensive deterioration of the timber superstructure elements, which has resulted in an 8" sag in the superstructure. For safety reasons the bridge will remain closed to all traffic until December 13 2002.

Preservation of the structure will involve replacement of deteriorated timbers by National Park Service Preservation Specialists utilizing 19th century crafts to replicate the handiwork of yesterday's craftsmanship. The lost of art of hewing round logs into square timbers with specialty axes will be used to craft the new timbers. Mortice and tenon joints typically used in the 19th century timber framing to join the timbers will be utilized to restore the structure. Craig Struble, Park Restoration Specialist, is overseeing the project.

Work will include the following preservation tasks:

• Construct shoring to support 115,000 lb timber frame bridge
• Remove 8" defection from superstructure and level bridge
• Remove and replace all 7 deteriorated 14" by 14" by 30' transverse floor beams
• Repair river undermining of bridge pier masonry in stream bed
• Restore structural stability to upstream and downstream timber frame truss assemblies
• Replace undersized timber components with structural rated components to resist wind and snow load conditions
• Replicate hand hewed timbers utilizing broad axes and ancient craftsmanship from 19th century practices.

National Park Service photo
(click photo for larger version)

-NPS-