STATIC AND DYNAMIC ELASTOMETRIC BRIDGE BEARING TESTS AT NORMAL AND LOW TEMPERATURES

INVESTIGATION WAS CONDUCTED TO ESTABLISH BY EXPERIMENTAL MEANS THE STRESS/STRAIN BEHAVIOR OF COMMERCIALLY AVAILABLE BRIDGE BEARING PADS UNDER CONDITIONS OF STATIC AND DYNAMIC LOADING IN COMPRESSION AND SHEAR AT TEMPERATURES DOWN TO MINUS 40 F. THE STATIC COMPRESSION AND SHEAR TESTS CONDUCTED ON NEOPRENE AND BUTYL AT NORMAL AND LOW TEMPERATURES REVEALED NO SERIOUS STRUCTURAL WEAKNESSES IN THE PADS. A LARGE STIFFENING EFFECT IS EXHIBITED BY NEOPRENE AND BUTYL AT LOW TEMPERATURES. BUTYL OFFERS LESS RESISTANCE TO STATIC SHEAR DEFORMATIONS THAN NEOPRENE. THE 1 INCH BUTYL ALSO SUSTAINS LARGER COMPRESSIVE DEFLECTIONS THAN NEOPRENE. THE LENGTH, WIDTH, THICKNESS AND HARDNESS OF EACH SPECIMEN WAS DETERMINED PRIOR TO THE DYNAMIC TESTS AND WERE REPEATED AFTER COMPLETION OF EACH TEST TO INDICATE CHANGES IN DIMENSIONS DUE TO TESTING. IT IS CONCLUDED THAT ALL ELASTOMERIC MATERIALS INVESTIGATED CAN SUSTAIN A LARGE NUMBER OF DYNAMIC COMPRESSION AND DYNAMIC SHEAR APPLICATIONS OF MAGNITUDES COMPARABLE TO THOSE FOUND IN PRACTICE WITHOUT SERIOUS SIGNS OF FATIGUE OR PHYSICAL DAMAGE. INTERNAL HEAT BUILD-UP DUE TO DYNAMIC COMPRESSION IS A CONTRIBUTING FACTOR TO THE INITIATION OF TENSILE CRACKS IN THE BULGING AREAS OF ELASTOMERIC BRIDGE BEARINGS. FOR BEARINGS OF THE SAME OVERALL PHYSICAL DIMENSIONS, A LAMINATED TYPE OF BEARING EXHIBITS MORE DESIRABLE STRESS/STRAIN PROPERTIES WITH RESPECT TO BOTH STATIC AND DYNAMIC LOADING THAN A HOMOGENEOUS BEARING. THE VERTICAL DEFLECTION OF ELASTOMERIC BRIDGE BEARINGS IS SUBSTANTIALLY INFLUENCED BY DYNAMIC LOADING IN COMPRESSION AND SHEAR. FOR SOME ELASTOMERS, INITIAL STATIC DEFLECTIONS /AS DEFINED IN THIS PAPER/ MAY BE INCREASED APPROXIMATELY BY AS MUCH AS 60 PERCENT DUE TO DYNAMIC COMPRESSION AND AS MUCH AS 100 PERCENT DUE TO DYNAMIC SHEAR.

• Supplemental Notes:
  • Ojhrp Rept NO 24, 101 PP, 55 FIG, 8 TAB, 12 REF
• Corporate Authors:

  University of Toronto

  Department of Geography, 100 St George Street
  Toronto, Ontario  Canada  M5S 3G3
• Authors:
  • Suter, G T
  • Collins, R A
• Publication Date: 1964-9

Subject/Index Terms

• TRT Terms: Bridge bearing pads; Compression; Compression tests; Deformation curve; Dynamic loads; Elastomers; Laminates; Low temperature; Neoprene; Rubber; Shear tests; Static loads; Tension; Volume changes
• Uncontrolled Terms: Tensile stress
• Old TRIS Terms: Butyl rubber; Compressive strength tests; Static loading
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00208295
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 11 1994 12:00AM