InTrans / Aug 14, 2018

Field Performance of Timber Bridges: 20. Gray Stress-Laminated Deck Bridge

The Gray bridge was constructed in the fall of 1991 in Gray, Maine. The bridge is a single-span, two-lane, stresslaminated deck structure that is approximately 24 ft long and 23 ft wide. It was constructed from chromated-copperarsenate- (CCA-) treated eastern hemlock grown in Maine. This report presents information on the design, construction, and field performance of this bridge. The field performance of the bridge was monitored for 6å_ years, beginning shortly after construction. During the field monitoring program, data were collected related to wood moisture content, force level of stressing bars, behavior under static truck loading, and overall structural condition. With the exception of having to be retensioned approximately every 3 years, the bridge is performing well, with no structural or serviceability deficiencies.