ELASTOMERIC BRIDGE BEARINGS

TESTS WERE MADE TO DETERMINE THE ADEQUACY OF ELASTOMERIC BEARINGS IN BRIDGE CONSTRUCTION AND TO ESTABLISH BEARING DESIGN CRITERIA. SAMPLES OF NEOPRENE, 6 IN. BY 12 IN. OF VARYING THICKNESS, MOLDED OR IN BONDED LAYERS, WERE TESTED. TEST EQUIPMENT INCLUDED A 500,000-LB SOUTHWARK-EMERY TENSION COMPRESSION MACHINE, A 40,000 LB HYDRAULIC JACK AND VARIOUS RECORDING GAUGES. THE REQUIRED COMPRESSIVE AND SHEAR LOADS WERE APPLIED DIRECTLY, ALTERNATELY AND IN COMBINATION FOR VARYING PERIODS. TEST PHASES INCLUDED VERTICAL DEFLECTION UNDER COMPRESSION HORIZONTAL AND VERTICAL DEFLECTION IN COMBINED COMPRESSION AND SHEAR, SHAPE EFFECTS, TIME-CREEP RELATIONSHIPS AND FATIGUE. ALL BEARING TYPES TESTED BORE CLOSE STRESS-STRAIN RELATIONSHIPS. WITHIN THE LIMITS OF THE TEST PROCEDURES IT IS ASSUMED THAT NEOPRENE-BASED BEARING PRODUCTS MEETING CURRENT SPECIFICATIONS HAVE SIMILAR PHYSICAL PROPERTIES. IT WAS FOUND THAT VERTICAL DEFLECTION INCREASED INVERSELY WITH DUROMETER READINGS, AND WITH TIME AND DYNAMIC LOADING, AND WERE PROPORTIONALLY GREATER WITH ADDED THICKNESS. TESTS FOR ADDITIONAL VERTICAL DEFLECTIONS SIMILAR TO INTERMITTENT LIVE BRIDGE LOADS OR DYNAMIC CREEP, INDICATE THAT STATIC DEFLECTIONS SHOULD BE INCREASED BY 50 PERCENT. BEARINGS TESTED INDICATED, IN EACH INSTANCE, SIMILAR HORIZONTAL DEFLECTIONS DUE TO HORIZONTAL SHEAR LOADS. RESISTANCE TO SHEAR DISTORTION INCREASED WITH THICKNESS AND STIFFNESS BUT WAS NOT AFFECTED BY DIRECT COMPRESSIVE LOADING OR BY SHAPE OR ORIENTATION OF BEARING. THE ABSENCE OF FATIGUE IN THE 3-HR ALTERNATING PHASE OF THE TESTS INDICATED THE NEED FOR A LONGER TESTING PERIOD IN THIS RESPECT /AUTHOR/

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/HRBBulletin/242/242-001.pdf
• Supplemental Notes:
  • No 242, pp 1-19, 22 FIG, 6 REF Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • Pare, R L
  • Keiner, E P
• Discussers:
  • McCready, S D
• Publication Date: 1960

Media Info

• Media Type: Digital/other
• Monograph Title: Bridges: bearing pads, foundations, scour and waterways
• Serial:
  • Highway Research Board Bulletin
  • Issue Number: 242
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Bridge bearings; Compression tests; Construction; Creep; Deformation curve; Design; Dynamic loads; Elastomers; Fatigue (Physiological condition); Neoprene; Shape; Shear strength; Testing equipment; Time
• Uncontrolled Terms: Design criteria
• Old TRIS Terms: Compressive strength tests; Shape factor; Time factor
• Subject Areas: Bridges and other structures; Construction; Design; Highways;

Filing Info

• Accession Number: 00208820
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Sep 16 1994 12:00AM