http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Effect of voids in grouted, post-tensioned concrete bridge construction
41 pages : digital, PDF file (3.19 MB) with color illustrations
Post-tensioned (PT) bridges have several advantages over other bridge types: they can span longer distances, can be constructed relatively fast, and are economical. The tendons of PT bridges are critical components, essentially the backbone of the PT bridge system. Tendons consist of strands, ducts, and grout that fill the interstitial space between the strands and ducts. Grout is intended to protect the strands from corrosion, especially when the duct is damaged or water or other deleterious substances infi ltrate the tendon. However, past construction practices and materials have resulted in voids in tendons. Corrosion of the strands in these tendons has resulted in bridge failures in Europe. More recently, voids have been detected in PT bridges in the United States with some of the strands in these voids exhibiting corrosion. In fact, tendon failures have been reported on PT bridges, especially in Florida, that are exposed to aggressive environments. This history has raised concerns about conditions in PT bridges in Texas. A recent inspection of tendons in PT bridges in Texas identified voids. However, all environments in Texas may not be classified as aggressive. Research was needed to assess how the environmental and other conditions, especially the conditions inside the voids in tendons, affect the corrosion of strands and how this corrosion influences the structural reliability of PT bridges. In addition, economical and high-performance grout materials and effi cient inspection and repair methods needed to be defined.
Title from PDF title screen (November 2, 2009).
Project performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration 0-4588
Seminar (Texas Transportation Institute) ; 0-4588-P2