EFFECTS OF DIAPHRAGMS IN CONTINUOUS SLAB AND GIRDER HIGHWAY BRIDGES

THE RESULTS OF A STUDY OF THE EFFECTS OF DIAPHRAGMS ON LOAD DISTRIBUTION OF CONTINUOUS, STRAIGHT, RIGHT SLAB AND GIRDER HIGHWAY BRIDGES ARE PRESENTED AND DISCUSSED. THE PARAMETERS FOR THE STUDY ARE: THE RELATIVE GIRDER STIFFNESS, H; THE RATIO OF THE GIRDER SPACING TO SPAN, B/A; THE BEAM SPACING, B; AND THE POSITION AND THE STIFFNESS OF THE DIAPHRAGMS. LOAD DISTRIBUTION CHARACTERISTICS OF BRIDGES SUBJECTED TO A SINGLE LOAD, 4-WHEEL LOADINGS ALIGNED IN THE TRANSVERSE DIRECTION AND TWO TRUCK LOADINGS WERE STUDIED. IN GENERAL, THE CRITERION FOR COMPARISON IS THE MAXIMUM MOMENTS, BOTH POSITIVE AND NEGATIVE, IN THE BEAMS DUE TO 4-WHEEL LOADINGS. THE VARIATIONS OF THE MAXIMUM MOMENTS WITH DIAPHRAGM STIFFNESS WERE STUDIED, AND THE CONCLUSIONS OF THIS INVESTIGATION WERE BASED ON THE ANALYSES OF A THREE-SPAN CONTINUOUS BRIDGE AND VARIOUS TWO-SPAN CONTINUOUS BRIDGES ALTHOUGH DIAPHRAGMS MAY IMPROVE THE LOAD DISTRIBUTION CHARACTERISTICS OF SOME BRIDGES WHICH HAVE A LARGE B/A RATIO, THE USEFULNESS OF DIAPHRAGMS IS MINIMAL AND THEY ARE HARMFUL IN MOST CASES. ON THE GROUND OF COST EFFECTIVENESS, IT IS RECOMMENDED THAT DIAPHRAGMS NOT BE INSTALLED IN HIGHWAY BRIDGES. THE COMPARISON OF THE DESIGN MOMENT COEFFICIENTS AS OBTAINED IN THIS INVESTIGATION AND THE AASHO RECOMMENDED DESIGN VALUES SHOWS THAT THE AASHO DESIGN COEFFICIENTS ARE UNCONSERVATIVE IN MANY CASES AND UNDULY CONSERVATIVE IN OTHERS.

  • Supplemental Notes:
    • Contract IHR-93 UILU-ENG-73-2006
  • Corporate Authors:

    University of Illinois, Urbana-Champaign

    Urbana, IL  USA  61801
  • Authors:
    • Wong, A Y
    • Gamble, W L
  • Publication Date: 1973-5

Media Info

  • Pagination: 123 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00208085
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: Interim
  • Files: TRIS, USDOT
  • Created Date: Apr 27 1974 12:00AM