STATE-OF-THE-ART: TIMBER AS A BRIDGE MATERIAL

The author discusses development needs and research needs for the use of timber as a bridge material. Developments needed include a timber railing design which meets the vehicle impact requirements of AASHTO; AASHTO bridge standards specific to bridges on low-volume roads; synthesized information on the design, construction, rehabilitation, and economics of timber bridges; increased education on wood as a structural material and experience with timber bridges on the part of engineers; documentation of the initial in-place cost and eventual life cycle economy of timber bridges compared to bridges comprised of other materials; more flexible highway funding for bridge projects; and comprehensive standard timber bridge plans. Research needs are divided into the subject areas of loadings, structural analysis, experimentation and product development, in-place performance, and design.