ADDITIONAL FATIGUE TESTS OF HYBRID PLATE GIRDERS UNDER PURE BENDING MOMENT

A SERIES OF FATIGUE TESTS OF HYBRID PLATE GIRDERS UNDER PURE BENDING MOMENT WAS PERFORMED. ASTM A441 STEEL WAS USED FOR THE FLANGES AND A36 STEEL WAS USED FOR THE WEBS. TWO GROUPS OF GIRDERS (THREE SPECIMENS FOR EACH GROUP) WERE TESTED. THESE TWO GROUPS DIFFER ONLY IN THE WEB THICKNESS; THE ONE HAD A WEB SLENDERNESS RATIO OF 144, AND THE OTHER HAD A WEB SLENDERNESS RATIO OF 192. ALTHOUGH THE OBJECTIVE OF THIS INVESTIGATION WAS TO COMPILE DATA ON THE FATIGUE STRENGTH OF HYBRID GIRDERS, SPECIAL EMPHASIS WAS PLACED ON ESTIMATING THE FATIGUE STRENGTH OF THE BENDING PANELS AT TWO MILLION CYCLES. TO ESTIMATE THE FATIGUE STRENGTH AT TWO MILLION CYCLES, A SEQUENTIAL SERIES OF RESPONSE TESTS WAS ADOPTED. THE MAXIMUM STRESS WAS KEPT AT 30 KSI (60 PERCENT OF SPECIFIED YIELD POINT OF A441 STEEL) AND THE STRESS RANGE WAS VARIED. (THE MAXIMUM STRESS AND THE STRESS RANGE IN THE FATIGUE TESTING IS EXPRESSED IN TERMS OF STRESSES IN THE FLANGES. FOR ALL THE SPECIMENS TESTED, THE FATIGUE CRACKS OCCURRED IN THE WEB ALONG THE TOE OF THE WEB-TO-STIFFENER FILLET WELD NEAR THE CUT-OFF END OF THE STIFFENERS. IT WAS NOTED THAT THE INITIATION OF THIS TYPE OF CRACK WAS IN CLOSE RELATION WITH THE TENSILE FIBER STRESSES IN THE WEB. THE DIFFERENCE IN WEB THICKNESS APPARENTLY WAS NOT SIGNIFICANT IN THE TESTS CARRIED OUT. THE STRESS MAGNITUDE AT THE POINTS WHERE THE CRACKS APPEARED WAS FOUND TO BE COMPARABLE WITH THE MEDIAN FATIGUE STRENGTH OF TENSION SPECIMENS WITH FILLET-WELDED ATTACHMENTS. FOR THE BENDING PANELS TESTED, THE MEDIAN FATIGUE STRENGTH AT TWO MILLION CYCLES WAS FOUND TO BE A STRESS RANGE OF 20 KSI AT A MAXIMUM STRESS OF 30 KSI. HOWEVER, MORE TESTS ARE CONSIDERED NECESSARY TO ESTABLISH THE FATIGUE STRENGTH MORE PRECISELY AND TO CARRY OUT A STATISTICAL ANALYSIS. THE S-N CURVE PRESENTED PROVIDES A SLIGHTLY CONSERVATIVE ESTIMATE OF THE FATIGUE STRENGTH OF THE GIRDERS IN THIS TEST SERIES. /AUTHOR/

• Supplemental Notes:
  • Hpr-1(6), NO 96
• 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:
  • Kurobane, Y
  • Fielding, D J
  • Toprac, A A
• Publication Date: 1967-5

Subject/Index Terms

• TRT Terms: Bending moments; Fatigue tests; Flanges; Girders; Plate girders; Stiffeners (Plates); Stresses; Tensile strength; Thinness; Webbing
• Uncontrolled Terms: Slenderness ratio
• Old TRIS Terms: Hybrid girders; Stiffeners
• Subject Areas: Bridges and other structures; Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00215855
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS, STATEDOT
• Created Date: Oct 23 1994 12:00AM