FATIGUE TESTS OF WELDED 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 AND WEB DEPTH 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 FILLER WELD AND NEAR THE END OF THE TRANSVERSE STIFFNER. 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:
  • Res Rept No 77-2F, VIII & 65 PP, 39 FIG, 5 TAB, 7 REF
• Corporate Authors:

  University of Texas, Austin

  Center for Highway Research, 200 West 21st Street
  Austin, TX  United States  78712

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590

  Bureau of Public Roads /US

  400 7th Street, SW
  Washington, DC  United States  20590

  Department of Transportation

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Lew, H S
  • Toprac, A A
• Publication Date: 1967-1

Subject/Index Terms

• TRT Terms: Accelerated tests; Cracking; Fatigue tests; Flanges; Girders; Joints; Plate girders; Repeated loads; Specimens; Steel; Stresses; Tension; Test procedures; Thickness; Webbing; Welds; Yield point
• Uncontrolled Terms: Membranes; Welded joints
• Old TRIS Terms: Hybrid girders; Membranes (Biology); Tension cracks
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00208363
• Record Type: Publication
• Files: TRIS, USDOT
• Created Date: Feb 6 1994 12:00AM