EFFECTS OF DIAPHRAMS IN BRIDGES WITH PRESTRESSED CONCRETE I- SECTION GIRDERS

THE RESULTS OF A STUDY OF THE EFFECTS OF THE NUMBER, stiffness, and locations of diaphragms in multi-beam simply SUPPORTED, HIGHWAY BRIDGES ARE PRESENTED. THE PARAMETERS STUDIED INCLUDED THE RELATIVE GIRDER STIFFNESS, H, THE RATIO OF GIRDER SPACING TO SPAN, B/A, THE GIRDER TORSIONAL STIFFNESS, THE GIRDER SPACING, AND THE LOCATION OF THE LOADS RELATIVE TO THE EDGE GIRDERS OF THE STRUCTURE. THE BEHAVIOR OF THE BRIDGES IS EVALUATED FOR SEVERAL TYPES OF LOADINGS, INCLUDING SINGLE LOADS AND GROUPS OF LOADS. THE BRIDGES STUDIED WERE DIVIDED INTO THREE GENERAL CATEGORIES ACCORDING TO THE UNIFORMITY OF LOAD DISTRIBUTION TO THE GIREDERS, AND DESIGN RECOMMENDATIONS REGARDING DIAPHRAGM ARRANGEMENTS AND STIFFNESSES ARE MADE. IN MOST STRUCTURES IN WHICH THE OUTER LINE OF WHEELS CAN FALL DIRECTLY OVER THE EDGE GIRDERS, DIAPHRAGMS SHOULD NOT BE USED, AS THEY WILL INCREASE THE CONTROLLING MOMENT IN THE BRIDGE. IN OTHER CASES, DIAPHRAGMS MAY BE EITHER HELPFUL OR HARMFUL, AND CRITERIA ARE DEVELOPED FOR DESIGN PURPOSES. THE INFLUENCE OF THE NUMBER OF DIAPHRAGMS WAS STUDIED, AND THE STRUCTURAL EFFECTS OF A SINGLE MIDSPAN DIAPHRAGM AND TWO DIAPHRAGMS LOCATED NEAR MIDSPAN WERE ABOUT THE SAME, THOUGH THE COST EFFECTIVENESS OF THE SINGLE DIAPHRAGM IS BETTER. THE CURRENT ARBITRARY PRACTICE OF DETERMINING LOCATION AND SPACING OF DIAPHRAGMS AS A FUNCTION OF SPAN LENGTH ALONE SHOULD BE CHANGED, AS MANY SHORT SPAN BRIDGES WHICH DO NOT INCLUDE DIAPHRAGMS COULD BENEFIT FROM THEM, AND MANY LONGER SPAN STRUCTURES which normally contain diaphragms either receive no benefit or are harmed by them. /TRRL/

• Authors:
  • Sithichaikasem, S
  • Gamble, W L
• Publication Date: 1972-2

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 287 p.
• Serial:
  • Ill Univ Hwy Res Lab Civil Eng Studies
  • Volume: 11
  • Issue Number: 383

Subject/Index Terms

• TRT Terms: Beams; Bridge superstructures; Design; Diaphragms (Engineering); Girders; Highway bridges; Load transfer; Prestressed concrete; Spacing; Stiffness; Torsion
• Uncontrolled Terms: Bridge spans; Design features
• Old TRIS Terms: Diaphragms
• Subject Areas: Bridges and other structures; Design; Highways;

Filing Info

• Accession Number: 00210242
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Files: TRIS
• Created Date: May 15 1974 12:00AM