PRESTRESS LOSS AND CREEP CAMBER IN A HIGHWAY BRIDGE WITH REINFORCED CONCRETE SLAB ON PRETENSIONED PRESTRESSED CONCRETE BEAMS

A NUMERICAL PROCEDURE USING A STEP-BY-STEP METHOD IS USED FOR COMPUTING BOTH ELASTIC AND TIME DEPENDENT STRAINS, DEFLECTIONS, AND PRESTRESS LOSSES IN FULL SIZE PRETENSIONED PRESTRESSED CONCRETE HIGHWAY BRIDGE BEAMS. BOTH LIGHTWEIGHT AND NORMAL WEIGHT STRUCTURAL CONCRETES ARE USED. THE METHOD USES CREEP AND SHRINKAGE FUNCTIONS, DERIVED FROM CONTROL SPECIMENS, FOR MAKING PREDICTIONS. THE COMPUTED STRAINS, DEFLECTIONS, AND PRESTRESS LOSSES AGREED WELL, FOR THE MOST PART, WITH MEASURED VALUES DURING THE TIME INTERVAL FROM DATE OF CASTING OF THE SLABS TO END OF TESTS. THE BEAMS WERE ABOUT 320 DAYS OLD WHEN THE SLAB WAS CAST, AND TESTS TERMINATED AT 660 DAY BEAM AGE. MEASURED ELASTIC BEAM DEFLECTIONS UNDER THE WEIGHT OF THE PLASTIC SLAB WERE A LITTLE OVER 50% OF THE DEFLECTIONS COMPUTED BY THEORY. PRESTRESS LOSSES WERE ABOUT 15% IN 40 FT. LONG LIGHTWEIGHT CONCRETE BEAMS AT 660 DAYS. THE 56 FT. LW BEAMS LOSS AT THE SAME AGE WAS ABOUT 21% AND THE NW BEAM 14-1/2%. THE CHANGES IN CAMBER AND PRESTRESS LOSSES AFTER THE SLAB WAS CAST WERE MINOR. /BPR/

• Supplemental Notes:
  • Hpr, 69-3f
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011

  Texas State Department of Highways & Public Transp

  11th and Brazos Streets
  Austin, TX  United States  78701

  Bureau of Public Roads /US

  400 7th Street, SW
  Washington, DC  United States  20590
• Authors:
  • Furr, H L
  • Sinno, R
  • Ingram, L L
• Publication Date: 1968-10

Subject/Index Terms

• TRT Terms: Beams; Bridge construction; Bridge foundations; Bridges; Concrete; Construction; Curvature; Deflection; Elastic analysis; Highway bridges; Lightweight concrete; Numerical analysis; Prestressed concrete; Prestressing; Pretensioning; Reinforced concrete; Slabs; Strain (Mechanics); Structural materials
• Old TRIS Terms: Elastic analysis (Structural); Strains
• Subject Areas: Bridges and other structures; Construction; Highways;

Filing Info

• Accession Number: 00207903
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS, STATEDOT
• Created Date: May 19 1994 12:00AM