Press-Lam Timbers for Exposed Structures

by John A. Youngquist, Engr.; Forest Products Lab., Forest Service, U.S. Dept. of Agriculture, Madison, Wisc.,
John L. Tschernitz, Chemical Engr.; Forest Products Lab., Forest Service, U.S. Dept. of Agriculture, Madison, Wisc.,
Russell C. Moody, Engr.; Forest Products Lab., Forest Service, U.S. Dept. of Agriculture, Madison, Wisc.,
Ronald W. Jokerst, Forest Products Technologist; Forest Products Lab., Forest Service, U.S. Dept. of Agriculture, Madison, Wisc.,
David S. Gromala, (A.M.ASCE), Engr.; Forest Products Lab., Forest Service, U.S. Dept. of Agriculture, Madison, Wisc.,


Serial Information: Journal of the Structural Division, 1979, Vol. 105, Issue 7, Pg. 1405-1416


Document Type: Journal Paper

Abstract: Parallel Laminated Veneer (PLV) products are manufactured by adhesive bonding of rotary-peeled veneer. It has been estimated that a production line PLV process could convert green logs into a finished structural laminate in less than an hour. Press-Lam, a PLV product under investigation at the U.S. Forest Products Laboratory, has exhibited decreases in variability of mechanical properties and increases in chemical preservative penetration and retention when compared to solid-sawn lumber. A prototype highway bridge entirely of Press-Lam has been erected by the Virginia Department of Highways and Transportation. This bridge was field-tested to its AASHTO HS-20 design load. Preliminary allowable stresses were determined by data obtained from destructive laboratory tests on 18 full-scale stringers and 10 sections of decking made from Douglas-fir Press-Lam. In the face of dwindling supplies of large structural timbers, PLV products are attractive alternatives for exposed structural applications.

Subject Headings: Wood structures | Wood | Highway bridges | Laminated materials | Laminating | Chemical properties | Highway transportation | Bridge design

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