This tri-level hood bridge system uses pressure-treated glu- laminated timbers and is designed to give an aesthetic look that would blend into the natural setting of a scenic area. The Keystone bridge is made up of 2 wood glu-laminated bridges: one arch bridge, and one timber girder bridge. It is designed so that each bridge carries 1-way traffic; however, each is constructed to be able to serve 2 lanes. The top arch bridge is 290 feet long and has a 26 foot mile roadway. The timber bridge is 170 feet in length and constructed with a horizontal curve radius of 381.97 feet. A construction problem which was successfully solved was the design of the longitudinal beams of the girder bridge spanning the roadway to give a reasonable depth for vertical clearance and provide the proper composite action between concrete slab and timber girders. Approximately 180,000 feet of glu-laminated material was used in addition to sawn timber for the fabrication of the component structurals. All timber used in the laminated beams was pressure treated (with pentachlorophenol bourne in a liquid gas medium which left the wood with a natural appearance) prior to fabrication.

  • Corporate Authors:

    American Wood Preservers Institute

    1651 Old Meadow Road
    McLean, VA  United States  22101
  • Publication Date: 1969-4

Media Info

  • Features: Figures; Photos;
  • Pagination: 11 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00153014
  • Record Type: Publication
  • Report/Paper Numbers: Report No. HD:0.25
  • Files: TRIS
  • Created Date: Jul 19 1977 12:00AM