Stress-laminated timber bridges were introduced into the United States in the late 1980s. Since then this concept has been used for more than 500 bridges constructed on roadways throughout the United States. To evaluate the performance of these bridges, the Forest Products Laboratory of the U.S. Department of Agriculture Forest Service and FHWA initiated a nationwide bridge-monitoring program. A field evaluation and the results obtained through that monitoring program for stress-laminated bridges that have been continuously monitored for 2 or more years after installation are presented. Included are discussions related to bridge design and construction, moisture content, stressing bar force, vertical creep, load test behavior, and condition evaluation. On the basis of the monitoring program results, the performance of stress-laminated timber bridges is generally satisfactory, although there are areas in which performance can be improved.
Live load deflection criteria for glued-laminated timber bridges
