INVESTIGATION OF A FULL-SIZE CONTINUOUS CONCRETE HIGHWAY BRIDGE PART I & II-DEAD LOAD EFFECTS AND LIVE LOAD EFFECTS

A THREE-SPAN CONTINUOUS REINFORCED CONCRETE BRIDGE WAS BUILT NEAR AUBURN UNIVERSITY FOR THE SOLE PURPOSE OF TESTING. THE BRIDGE IS OF A STANDARD DESIGN BY THE ALABAMA HIGHWAY DEPARTMENT, WITH THE MAJOR EXCEPTION BEING THAT THE TEST BRIDGE IS ONLY HALF-WIDTH (TWO GIRDERS INSTEAD OF FOUR). VARIOUS MEASUREMENTS MADE WERE: REACTIONS, DEFLECTIONS, SURFACE STRAINS, STEEL STRAINS, LONGITUDINAL MOVEMENTS, AND INTERNAL AND AMBIENT TEMPERATURES. LIVE LOAD TESTS AND DEAD LOAD TEST ARE REPORTED. THE DEAD LOAD TEST SHOWED THAT THERMAL CHANGES EXERTED THE STRONGEST INFLUENCE ON THE BEHAVIOR OF THE BRIDGE. NO DIRECT RELATIONSHIP BETWEEN THE MAGNITUDE OF THE CHANGES AND TEMPERATURE COULD BE ESTABLISHED. THE SUM OF THE REACTIONS OF THE GIRDERS WAS SUBJECT TO CONTINUOUS VARIATION, INCREASING WITH RISING TEMPERATURE, AND VICE VERSA. THE DIRECT EFFECTS OF DIFFERENTIAL SHRINKAGE COULD NOT BE ASSESSED AND NO DISCERNIBLE FLUCTUATIONS OF THE REACTION COULD BE ATTRIBUTED TO SHRINKAGE. SHORT-TERM DEFLECTIONS IN THE END SPANS WERE MUCH SMALLER THAN PREDICTED. ABNORMAL OR UNSIGHTLY CRACKING OF THE TEST SPANS DID NOT OCCUR. THE CHANGES IN THE REACTIVE FORCES WERE OF SUCH MAGNITUDE THAT, IN CONJUNCTION WITH LIVE AND IMPACT LOADING, VERY SEVERE CRACKING WOULD BE POSSIBLE BECAUSE OF THE INCREASES OF STRESS. THE LIVE-LOAD STUDY SHOWED THAT ELASTIC ANALYSES BASED UPON THE ASSUMPTION THAT CONCRETE HAS NO TENSILE STRENGTH IS HIGHLY CONSERVATIVE WITHIN THE RANGE OF LOADS APPLIED. FOR TRANSIENT LOADS TENSION OF THE CONCRETE APPEARS TO CONTRIBUTE SIGNIFICANTLY TO THE FLEXURAL STRENGTH OF THE BRIDGE. THE DISTRIBUTION OF THE REACTIVE FORCES AMONG THE SUPPORTS WAS IN CLOSE AGREEMENT WITH THAT PREDICTED BY TRADITIONAL MEANS. LIVE- LOAD DEFLECTIONS CAN BE PREDICTED WITH FAIR ACCURACY BY CLASSIC THEORY AND SIMPLIFYING THE ASSUMPTION THAT THE GROSS CONCRETE SECTION ALONE IS RESPONSIBLE FOR THE STIFFNESS OF THE STRUCTURE. ATTEMPT WAS MADE TO DEVELOP A MATHEMATICAL APPROACH TO THE PROBLEM OF STRESS DISTRIBUTION BUT THIS DID NOT PROVE FEASIBLE. INSTRUMENTATION LEFT MUCH TO BE DESIRED.

• Supplemental Notes:
  • Hpr Report NO 24, 87 PP, 40 FIG, 13 TAB, 2 APP
• Corporate Authors:

  Auburn University

  Department of Civil Engineering, Harbert Engineering Center
  Auburn, AL  United States  36849

  Alabama State Highway Department

  11 South Union Street
  Montgomery, AL  United States  36130

  Bureau of Public Roads /US

  400 7th Street, SW
  Washington, DC  United States  20590
• Authors:
  • Hudson, F M
• Publication Date: 1967-6

Subject/Index Terms

• TRT Terms: Concrete bridges; Continuously reinforced concrete pavements; Deflection tests; Deformation curve; Highway bridges; Live loads; Load tests; Shrinkage; Static loads; Strain (Mechanics); Testing
• Uncontrolled Terms: Longitudinal movement
• Old TRIS Terms: Continuous reinforcement; Strains
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00208401
• Record Type: Publication
• Files: TRIS, STATEDOT
• Created Date: Feb 13 1994 12:00AM