A DYNAMIC STRESS STUDY OF A COMPOSITE SPAN BRIDGE WITH CONVENTIONAL AND ELASTOMERIC BEARINGS

AN EXPERIMENTAL STUDY IS DESCRIBED OF THE EFFECTS OF DYNAMIC LOADING ON THE VERTICAL COMPRESSIVE DEFLECTIONS OF ELASTOMERIC BEARINGS AND THE INFLUENCE OF THE FLEXIBLE BEARINGS ON THE RESPONSE OF THE SUPPORTED SPAN. THE PRIMARY TEST STRUCTURE WAS AN ACTUAL STEEL BEAM COMPOSITE HIGHWAY BRIDGE SPAN DYNAMICALLY LOADED BY A TEST VEHICLE CLOSELY SIMULATION AN AASHO HS20-44 STANDARD TRUCK. THE BEARINGS INVESTIGATED INCLUDED ONE SET OF CONVENTIONAL STEEL ROCKER PLATE ASSEMBLIES AND FIVE SETS OF ELASTOMERIC PADS REPRESENTING A WIDE RANGE OF PRACTICAL DESIGN PARAMETERS. A SURVEY OF THE FINDINGS OF PRIOR LABORATORY STUDIES OF THE BEHAVIOR OF ELASTOMERIC BEARINGS UNDER VARIOUS ENVIRONMENTAL AND LOADING CONDITIONS IS BRIEFLY PRESENTED, AND THE COMMONLY USED COMPRESSION-DEFLECTION RELATIONSHIP AND DESIGN PROCEDURE ARE REVIEWED. THE THEORY AND CONCLUSIONS OF TWO ANALYATICAL STUDIES OF THE INFLUENCE OF FLEXIBLIE SUPPORTS (BY OTHERS) ARE SUMMARIZED AND COMPARED WITH THE RESULTS OF A STUDY OF A MODEL BRIDGE SPAN ON ELASTOMERIC BEARINGS. THE ANALYTICAL AND MODEL STUDIES INDICATED THAT ELASTOMERIC BEARINGS WOULD REDUCE BOTH THE FREQUENCY OF VIBRATION OF THE SUPPORTED SPAN AND THE FLEXURAL STRESS IN THE STRUCTURAL MEMBERS AT RESONANCE. WHILE THE ACCEPTED COMPRESSION-DEFLECTION RELATIONSHIP FOR ELASTOMERIC PADS WAS VERIFIED EXPERIMENTALLY IN THE SUBJECT STUDY FOR BOTH STATIC AND DYNAMIC LOADING, IT WAS CONCLUDED THAT DEFLECTIONS OF ACTUAL BEARINGS UNDER EITHER TYPE OF LOADING WOULD BE LESS THAN THOSE PREDICTED BY THE STANDARD DESIGN CURVES. THE EFFECT OF THE BEARINGS IN REDUCING THE FREQUENCY OF VIBRATION OF THE SPAN WAS FOUND TO BE SLIGHT. UNDER THE REALISTIC LOADING CONDITION UTILIZED, NO PRACTICAL ADVANTAGE WAS INDICATED IN REDUCED FLEXURAL STRESSES OR INCREASED DAMPING OF VIBRATIONS. HOWEVER, A TREND TOWARD INCREASED DEFLECTIONS OF THE SPAN ON ELASTOMERIC BEARINGS WAS NOTED AT ALL SPEEDS OF THE TEST VEHICLE. GENERAL FINDINGS ON THE EFFECTS OF DYNAMIC LOADING, UNRELATED TO THE NATURE OF THE BEARINGS, ARE ALSO PRESENTED. /AUTHOR/

• Supplemental Notes:
  • 0554, 4322-022
• Corporate Authors:

  Virginia Highway Research Council

  Charlottesville, VA  United States 

  Virginia Department of Highways

  Richmond, VA  United States  23219

  Bureau of Public Roads /US

  400 7th Street, SW
  Washington, DC  United States  20590
• Authors:
  • McKeel, W T
  • Kinnier, H L
• Publication Date: 1970

Subject/Index Terms

• TRT Terms: Bridge bearings; Bridge construction; Bridge decks; Bridge foundations; Bridge superstructures; Bridges; Composite materials; Composite structures; Compression; Construction; Deflection; Dynamic loads; Elastomers; Steel; Stresses; Vibration
• Uncontrolled Terms: Bridge spans; Model tests
• Subject Areas: Bridges and other structures; Construction; Highways;

Filing Info

• Accession Number: 00207939
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS, STATEDOT
• Created Date: Jul 14 1970 12:00AM