This section addresses the design of two types of glulam timber bridges : beam bridges with transverse decks and longitudinal glulam deck (slab) bridges. The material presented in the section is based on the 1992 edition of the AASHTO Standard Specifications for Highway Bridges (AASHTO specifications), including interim specifications through 1993. When specific design requirements or criteria are not addressed by that specification, recommendations are based on referenced standards and specifications or commonly accepted design practice. Because AASHTO specifications are periodically revised to reflect new developments in bridge design, the designer should refer to the latest edition for the most current requirements. This section is not intended to serve as a substitute for current specifications.