THE EFFECT OF MIDSPAN DIAPHRAGMS ON LOAD DISTRIBUTION IN A PRESETRESSED CONCRETE BOX-BEAM BRIDGE, PHILADELPHIA BBIDGE

THE FIELD TESTING OF AN EXISTING BEAM-SLAB BRIDGE CONSTRUCTED WITH PRESTRESSED CONCRETE SPREAD BOX GIRDERS IS DESCRIBED. THE MAIN PURPOSE OF THIS STUDY WAS TO EXPERIMENTALLY INVESTIGATE THE EFFECT OF MIDSPAN DIAPHRAGMS ON DISTRIBUTION OF VEHICULAR LOADS TO EACH OF THE LONGITUDINAL BEAMS. THE BRIDGE WAS TESTED FIRST WITH THE DIAPHRAGM IN PLACE, AND THEN AGAIN AFTER THE DIAPHRAGMS HAD BEEN REMOVED. IT WAS FOUND THAT THE MIDSPAN DIAPHRAGMS DID TRANSMIT LOAD LATERALLY. THE DISTRIBUTION CONEFFICIENTS AND DEFLECTIONS FOR GIRDERS DIRECTLY UNDER THE VEHICULAR LOADS WERE SLIGHTLY REDUCED BY THE USE OF THE DIAPHRAGMS, WHEN THE BRIDGE WAS LOADED WITH ONE TRUCK. HOWEVER, OWING TO THE COMPENSATING EFFECTS WHEN SEVERAL LANES WERE LOADED SIMULTANEOUSLY, THE DISTRIBUTION FACTORS WERE NOT APPRECIABLY AFFECTED BY THE USE OF THE DIAPHRAGMS. IT WAS ALSO FOUND THAT THE EXPERIMENTALLY DETERMINED DISTRIBUTION FACTORS FOR INTERIOR GIRDERS WERE CONSIDERABLY LESS THAN THE PDH DESIGN VALUES, WHILE FOR EXTERIOR GIRDERS, THE EXPERIMENTAL VALUES WERE GREATER THAN THE DESIGN VALUES. THE EFFECT OF GIRDER SPACING WAS STUDIED BY COMPARING THE TEST RESULTS WITH THOSE FROM THE STUDY OF ANOTHER BRIDGE OF SIMILAR CONSTRUCTION (DREHERSVILLE BRIDGE - 1965). IN ADDITION, AN EVALUATION OF THE APPLICABILITY OF THE GUYON- MASSONNET LOAD DISTRIBUTION THEORY WAS INVESTIGATED BY COMPARING THE RESULTS WITH THE VALUES PREDICTED BY THE THEORY. /AUTHOR/

• Supplemental Notes:
  • Hpr-1(5), 315, 045
• Corporate Authors:

  Lehigh University

  Bethlehem, PA  United States  18015

  Pennsylvania Department of Highways

  400 North Street
  Harrisburg, PA  United States  17120-0095

  Bureau of Public Roads /US

  400 7th Street, SW
  Washington, DC  United States  20590
• Authors:
  • Lin, C
  • VanHorn, D A
• Publication Date: 1968-6

Subject/Index Terms

• TRT Terms: Beams; Box girders; Diaphragms (Engineering); Field tests; Girder bridges; Girders; Highway bridges; Load tests; Load transfer; Motion; Motor vehicles; Prestressed concrete; Prestressing; Spacing; Theory
• Uncontrolled Terms: Lateral loads; Moving vehicles
• Old TRIS Terms: Diaphragms; Midspan
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00207890
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS
• Created Date: Oct 28 1994 12:00AM