TECHNIQUES FOR MEASURING EXISTING LONG-TERM STRESSES IN PRESTRESSED CONCRETE BRIDGES. VOLUME 1: ANALYTICAL, LABORATORY, AND FIELD STUDIES

This volume summarizes the state-of-the-art, analytical, laboratory, and field studies performed to evaluate the feasibility of the flat-jack direct stress measurement technique to be used on prestressed concrete bridges. Several strain relief methods, including boring and slitting techniques, were evaluated by performing analytical studies. The flat-jack slitting technique was determined to be the most promising. Laboratory studies indicated that concrete internal stress could be measured to within +/- 125 psi with a 90% confidence level. Laboratory tests were performed on unreinforced, reinforced, and prestressed concrete specimens. Additional variables included member thickness, magnitude of stress, and stress distribution. Various linear regression analyses were performed to determine the best relationship between flat-jack canceling pressure and internal concrete stress. Direct stress measurements taken on a 25-year-old prestressed concrete highway girder were similar to those determined from laboratory testing on companion girders.

• Record URL:
  https://ntlrepository.blob.core.windows.net/lib/15000/15600/15677/PB2000100278.pdf
• 
• Corporate Authors:

  Construction Technology Laboratories, Inc.

  5400 Old Orchard Road
  Skokie, IL  United States  60077-1030

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Overman, T R
  • Hanson, N W
  • Rabbat, B G
  • Morgan, B J
  • Zwiers, R I
  • SHIU, K N
• Publication Date: 1999-9

Language

• English

Media Info

• Pagination: 288 p.

Subject/Index Terms

• TRT Terms: Field tests; Laboratory tests; Linear regression analysis; Measuring methods; Nondestructive tests; Prestressed concrete bridges; State of the art studies; Stresses
• Uncontrolled Terms: Flat jack slitting
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00795276
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: FHWA-RD-99-178,, CR-4995-4321-1,, Final Report
• Contract Numbers: DOT-FH-61-82-C-00020
• Files: NTL, TRIS, USDOT
• Created Date: Jul 13 2000 12:00AM