Construction methods and costs of stress-laminated timber bridges

Modern timber bridges are being considered by several states as a cost-effective alternative to steel and concrete bridges for municipal and rural use. Before full-scale adoption of stress-laminated timber bridges can occur, a U.S. bridge specification needs to be developed incorporating research findings from experimental structures that have recently been built in this country. Although much attention has been focused on defining structural behavior and modeling prestress forces, little has been written about construction methods, engineering development, and the transfer of construction technology. This paper presents the results of an analysis of the construction process for a prototype stress-laminated timber-deck bridge. The constructibility, material specifications, projected maintenance, and life-cycle costs are addressed and compared to conventional bridge construction. This case study in Connecticut documents that a relatively short project duration was achieved (three months), along with significant cost savings, despite the experimental nature of the study.