CREEP OF CONCRETE UNDER NON-UNIFORM STRESS DISTRIBUTION AND ITS EFFECT ON CAMBER OF PRESTRESSED CONCRETE BEAMS

A TEST PROGRAM WAS INITIATED TO GATHER DATA ON THE CREEP DEFORMATION OF CONCRETE OF THREE DIFFERENT CROSS SECTIONS /TEE, TRIANGULAR AND SQUARE/ SUBJECTED TO THE FOLLOWING FOUR STRESS DISTRIBUTIONS' 2000 PSI COMPRESSION UNIFORM, LINEAR DISTRIBUTIONS VARYING FROM 150 PSI TENSION TO 2000 PSI COMPRESSION AND FROM ZERO TO 2000 PSI COMPRESSION, AND A TRAPEZOIDAL DISTRIBUTION FROM 200 PSI TO 1200 PSI IN COMPRESSION. A REVIEW WAS MADE OF THE FOUR ACCEPTED THEORETICAL METHODS FOR THE ANALYSIS OF CREEP IN CONCRETE AND AN ANNOTATED BIBLIOGRAPHY ON CREEP WAS PREPARED. A RHEOLOGICAL MODEL WAS FORMULATED FROM THE EXPERIMENTAL DATA TO PROVIDE A SIMPLE, WORKABLE ANALYSIS OF THE CREEP OF CONCRETE WHICH EXPRESSES THE OBSERVED BEHAVIOR MATHEMATICALLY. IT WAS CONCLUDED THAT THE SPECIFIC CREEP FOR UNIFORM STRESS DISTRIBUTION DETERMINED FROM THE EXPERIMENTAL MEASUREMENTS COULD BE SATISFACTORILY SIMULATED BY THE MATHEMATICAL MODEL AND THAT THE SPECIFIC CREEP FOR NON- UNIFORM DISTRIBUTION COULD BE CALCULATED BY MULTIPLYING THE UNIFORM STRESS VALUE BY AN EXPERIMENTALLY DETERMINED FACTOR. THE FACTORS VARIED WITH TIME AND A LONG TERM VALUE WAS SUGGESTED FOR DESIGN USE. THE RESULTS OF THE RESEARCH WERE APPLIED TO A THEORETICAL ANALYSIS OF THE EFFECT OF CREEP ON CAMBER OF A PRECAST PRESTRESSED CHANNEL BEAM. THE CONSIDERATION OF THE NON- UNIFORM STRESS DISTRIBUTION RESULTED IN A CALCULATED UPWARD INCREASE OF CAMBER AT 100 DAYS OF 2.26 TIMES THE INITIAL CAMBER.

• Supplemental Notes:
  • JUN64
• Corporate Authors:

  North Carolina State University, Raleigh

  Raleigh, NC  United States  27695
• Authors:
  • Zia, P
  • Stevenson, J F
• Publication Date: 1964-6

Subject/Index Terms

• TRT Terms: Beams; Bibliographies; Compression; Concrete; Creep; Cross sections; Curvature; Data collection; Deformation curve; Frames; Loads; Mathematical models; Precast concrete; Prestressed concrete; Prestressing; Rheology; Shape; Specimens; Standardization; Structural design; Structural members; Theory; Time
• Uncontrolled Terms: Structural shapes
• Old TRIS Terms: Concrete creep
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00207730
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Report/Paper Numbers: Hps-1/27/
• Files: TRIS
• Created Date: Oct 1 1994 12:00AM