Glulam Timber Deck Bridges: Final Report

About the report:

This report discusses the construction and initial condition of the Virginia Department of Highways and Transportation's first three bridges built with glulam panels on steel stringers. The data show that superstructures with glulam deck panels are more expensive than the conventional alternative of solid plank on steel stringers. It is felt that in some instances the higher cost may be justified because the data indicate that the glulam superstructures can be constructed about 45% faster than the conventional alternative and because it is anticipated that maintenance will be less. In general, the bridge superstructures were assembled quickly and easily but many of the panels were wider at the ends than in the middle, which resulted in obvious gaps between the panels and decks which were longer than were specified in the plans. The panels were more than adequately treated with creosote and the excess creosote bleeding from them was undesirable. Panels on two of the three bridges exhibited an initial moisture content in excess of the 16% considered to be the upper limit for assuming a dry stress condition and a further evaluation of the in-service moisture condition is recommended. Cracks developed in the bituminous concrete wearing surface on one of the bridges within four weeks after it was installed.

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