FATIGUE STRENGTH OF HYBRID PLATE GIRDERS UNDER CONSTANT MOMENT

TWO SERIES OF FATIGUE TESTS ON WELDED HYBRID PLATE GIRDERS ARE DESCRIBED. THE FIRST SERIES CONSISTED OF FOURTEEN PANEL SPECIMENS AND THE SECOND SERIES CONSISTED OF SIX FULL LENGTH SPECIMENS. IN BOTH SERIES, THE CENTER TEST PANEL /OR PANELS/ WAS SUBJECTED TO PURE BENDING MOMENT. THE TEST SPECIMENS HAD ASTM A514 STEEL FLANGES AND ASTM A36 STEEL WEBS. FLANGE DIMENSIONS WERE KEPT CONSTANT IN ALL TEST SPECIMENS. THE WEB THICKNESSES USED WERE 1/8, 1/4, AND 3/8 INCH. THE MAXIMUM STRESSES APPLIED TO EACH OF THE TWO GROUPS OF SPECIMENS WERE 20, 30, 40 AND 50 KSI WITH STRESS RANGES OF 10, 15, AND 25 KSI. THE PRIMARY OBJECTIVES OF THE INVESTIGATION WERE' /1/ TO DETERMINE THE MANNER IN WHICH THIN WEB HYBRID GIRDERS FAIL WHEN SUBJECTED TO REPEATED LOADS, AND /2/ TO DETERMINE WHAT FACTORS INFLUENCE THE FATIGUE STRENGTH OF THIN WEB GIRDERS. THE TEST SETUP AND TEST PROCEDURES ARE DESCRIBED AND THE TEST RESULTS ARE ANALYZED AND DISCUSSED. IT IS CONCLUDED THAT, REGARDLESS OF THE WEB THICKNESS, FOR THE SPECIMENS SUBJECTED TO APPLIED STRESS BELOW THE YIELD POINT OF THE WEB MATERIAL, NO CRACKS WERE FOUND WITHIN TWO MILLION CYCLES. HOWEVER, WHEN APPLIED STRESSES EXCEEDED THE YIELD POINT OF THE WEB STEEL, THE WEB FLEXING ACTION COUPLED WITH THE MEMBRANE STRESS CAUSED THE DEVELOPMENT OF FATIGUE CRACKS ALONG THE TOE OF THE COMPRESSION FLANGE TO WEB FILLET WELD AND NEAR THE END OF THE TRANSVERSE STIFFENER. VARIOUS FATIGUE CRACKS CAUSED BY FABRICATION IRREGULARITIES WERE ALSO FOUND IN THE SPECIMENS STRESSED BEYOND THE WEB YIELD POINT. IN ALL CASES THE FINAL FAILURE OF THE SPECIMEN WAS ACCOMPANIED BY A FRACTURE IN THE TENSION FLANGE. /AUTHOR/

• Supplemental Notes:
  • Hpr-1/5/, 77-2F
• Corporate Authors:

  University of Texas, Arlington

  Arlington, TX  United States  76010

  Texas State Department of Highways & Public Transp

  11th and Brazos Streets
  Austin, TX  United States  78701
• Authors:
  • Toprac, A A
  • Lew, H S
• Publication Date: 1966-6

Subject/Index Terms

• TRT Terms: Accelerated tests; Analysis; Bending moments; Fatigue (Mechanics); Fatigue tests; Flanges; Flexure; Fracture mechanics; Girders; Panels; Plate girders; Repeated loads; Specimens; Steel; Stresses; Tension; Test procedures; Webbing; Weldments
• Uncontrolled Terms: Fatigue life; Membranes
• Old TRIS Terms: Flexing; Full scale specimens; Hybrid girders; Membranes (Biology); Test results
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00207820
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS, STATEDOT
• Created Date: Feb 20 1994 12:00AM