BACKGROUND: A "decked" concrete girder is a precast, prestressed concrete I-beam, bulb-tee, or multi-stemmed girder with an integral deck that is cast and prestressed with the girder. These girders are manufactured in precast concrete plants under closely controlled and monitored conditions, transported to the construction site, and erected such that flanges of adjacent units abut each other. Load transfer between adjacent units is provided using specially designed connections. Sections that are not too long or too heavy for transportation by truck can be used to construct long-span girder bridges. This type of bridge construction provides the benefits of rapid construction, improved safety for construction personnel and the public, and improved structural performance and durability.
In spite of their benefits, the use of decked precast, prestressed concrete girders has been limited because of concerns about certain design and construction issues that are perceived to influence the structural integrity of the bridge system. These issues include connections between adjacent units, longitudinal joints, longitudinal camber and cross slope, live load distribution, continuity for live load, lateral load resistance, skew effects, maintenance, replaceability and other factors that influence constructibility and performance.
Research was needed to address the issues that significantly influence the performance of long-span decked precast, prestressed concrete girder bridges and to develop guidelines for their design and construction. These guidelines will provide highway agencies with the information necessary for considering a bridge construction method that is expected to reduce the total construction time, improve public acceptance, reduce accident risk, and yield economic and environmental benefits.
OBJECTIVE: The objective of this research was to develop design and construction guidelines for long-span decked precast, prestressed concrete girder bridges.for consideration and adoption by the American Association of State Highway and Transportation Officials (AASHTO) as part of the AASHTO LRFD Bridge Design Specifications.
Status: The research is now complete althouh the planned full-scale testing of a longitudinal joint was not conducted. As a result, transverse continuity for moment and shear was not addressed and the recommendations developed in this project for future full deck replacement were not evaluated. No further work is planned under this project.
Product Availability: A 2-part un-reviewed “wrap-up” final report on the completed work was prepared. One part of the report, referred to as Final Report, describes the completed research and includes 7 appendices that provide details on the literature review, test results, and data analysis. The other part, referred to as Final Report: Guidelines, provides guidelines for the design and construction of decked precast, prestressed concrete girder bridges.