Field applications of prestressed laminated wood bridge decks

Abstract

The concept of prestressing laminated wood bridge decks was conceived in Ontario in 1976 as a method of upgrading existing deteriorated nailed laminated wood decks. The success of this technique as a method of rehabilitation prompted considerable research and development aimed at introducing it into new construction. This work led to the formation of a comprehensive set of design specifications, which have since been adapted into the Ontario highway bridge design code and were included in the 1983 edition.Since its inception in 1976, the prestressed wood concept has been used many times, and by 1985, more than 16 bridges incorporated the concept in various ways. The objective of this paper is to discuss a number of these field structures in order to demonstrate the flexibility of the prestressed wood deck system. In new construction, the system has been applied to both longitudinally and transversely laminated decks including on-site deck assembly as well as a preassembled deck panel system.The paper describes the applicability of the system, construction sequence, and field problems. In addition, construction costs for some of the applications, as derived from field data, are discussed. Key words: wood, bridges, prestressed wood decks, laminated decks, preassembled deck panels.