Statistics reveal a large number of short-span bridges in this country, many of which are, or soon will be, in need of replacement. Timber has traditionally been used as a low-cost building material for short-span bridges on low-volume roads. With the development of superhighways during the past 3 or 4 decades, timber use in bridge construction has declined. Timber has good strength characteristics aswell as being resistant to impact loading and damage from road salts. Proper preservative treatment can make wood a durable, long-term building material. Development of engineered timber products and systems has made modern timber bridges practical, reliable, and often the lowest-cost alternative. Products such as glued laminated beams and panels, laminated veneer lumber, and stressed deck systems have increased durability and feasible span lengths. Experience on usda forest service roads has shown that the costs of timber bridges are consistently competitive for shorter spans, up to 30 ft, particularlyon low-volume roads. Timber should be considered as a viable building material for many of the nation's deteriorating bridges. This paper appears in transportation research record no. 1291, Fifth international conference on low-volume roads, may 19-23, 1991, raleigh, north carolina, volume 1
Abstract