DYNAMIC TESTS OF TWO CANTILEVER TYPE, DECK STEEL GIRDER BRIDGES

A CONDENSED VERSION OF A 1960 REPORT ON FIELD STUDIES CONDUCTED COOPERATIVELY BY THE STATE AND THE BUREAU OF PUBLIC ROADS IS PRESENTED. THE PRIMARY OBJECTIVE WAS TO MEASURE, AND COMPARE WITH DESIGN ASSUMPTIONS, THE DYNAMIC AMPLIFICATION OF STRAIN AND DEFLECTION IN TYPICAL CANTILEVER TYPE BRIDGES PREVALENT IN NEBRASKA. STRAIN AND DEFLECTION GAGES AT CRITICAL POINTS WERE LOCATED SUCCESSIVELY ON TWO STRUCTURES AT WIDELY SEPARATED LOCATIONS IN THE STATE. ACCURATELY WEIGHED AND MEASURED TEST VEHICLES WERE DRIVEN ACROSS EACH OF THE BRIDGES OVER A BROAD RANGE OF SPEEDS AND LATERAL LANE POSITIONS WHILE THE SIMULTANEOUS DYNAMIC RESPONSES AT ALL GAGE POINTS ON THE BRIDGE WERE RECORDED. COMPARABLE LIVE LOAD STRAINS AND DEFLECTIONS WERE LESS THAN CALCULATED DUE TO THE PARTIAL COMPOSITE ACTION USUALLY INDUCED IN NON-COMPOSITE DESIGN BRIDGES BY FRICTION BETWEEN SLAB AND GIRDER AND TRANSVERSE STIFFNESS. THE MAGNITUDE OF TORSIONAL VIBRATIONS OBSERVED ON THE WIDER OF THE TWO BRIDGES INDICATED THAT A DANGEROUS RESONANT TORSIONAL RESONANCE MIGHT DEVELOP AT HIGHER VEHICLE SPEEDS THAN WERE ATTAINED IN THE TEST. IMPACT PERCENTAGES ASSOCIATED WITH THE HIGH VALUES OF LIVE LOAD STRAIN INDICATED THAT THE DESIGN SPECIFICATIONS WERE ADEQUATE AT LEAST FOR THE SMOOTH ROADWAY CONDITION ENCOUNTERED IN THE TESTS.

• Supplemental Notes:
  • Hpr-1/2/, AUG64
• Corporate Authors:

  Nebraska Department of Roads

  1500 Highway 2, P.O. Box 94759
  Lincoln, NE  United States  68509
• Publication Date: 1964-8

Subject/Index Terms

• TRT Terms: Alternatives analysis; Cantilevers; Deflection; Deflection tests; Design; Dynamic loads; Dynamic tests; Field studies; Friction; Girder bridges; Live loads; Measurement; Metal bridges; Steel bridges; Strain (Mechanics); Strain gages; Studies; Testing; Torsion tests; Traffic speed; Vehicles
• Uncontrolled Terms: Design criteria; Dynamic response
• Geographic Terms: Nebraska
• Old TRIS Terms: Speed studies; Strains
• Subject Areas: Bridges and other structures; Design; Highways; Vehicles and Equipment;

Filing Info

• Accession Number: 00207727
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS, STATEDOT
• Created Date: Sep 1 1994 12:00AM