Institute for Transportation

Structural glued laminated timber has been successfully used as a highway bridge material in the United States for approximately 50 years. From the mid 1940’s to the mid 1980’s,
virtually all of these bridges were longitudinal girder or arch type glulam superstructures with a nail-laminated wood deck or some form of composite concrete deck. The next evolution of
these bridges occurred between the early 1970’s and the late 1980’s, when the large majority of these bridges were constructed using longitudinal glulam girders and transverse glulam decks or longitudinal glulam deck superstructures manufactured from conventional softwood lumber species. Recently, highway bridge applications employing glued laminated timber have been expanded to include alternative wood species and new designs utilizing the concept of stress-laminating. Additionally, current research using composite plastic materials in injunction with glulam may lead to future innovations in timber highway bridges.