THE EFFECTIVENESS OF DIAPHRAGMS IN STEEL STRINGER BRIDGES

THIS REPORT DESCRIBES AN EXPERIMENTAL STUDY TO EVALUATE THE ACTION OF STEEL DIAPHRAGMS AS LOAD DISTRIBUTING MEMBERS IN A STEEL STRINGER BRIDGE. TO CLARIFY THE ROLE OF THE DIAPHRAGMS, EACH TRANSVERSE STRUCTURAL MEDIUM, THE DIAPHRAGMS AND THE SLAB WERE CONSIDERED SEPARATELY AND THEN COMPARED TO FORMULATE AN UNDERSTANDING OF THE COMPOSITE BEHAVIOR. FIELD TESTS WERE MADE IN TWO PHASES ON A FULL SCALE BRIDGE . THE FIRST PHASE DEALT WITH TESTING THE BRIDGE AS A GRIDWORK OF STRINGERS AND DIAPHRAGMS ONLY, WHILE THE SECOND PHASE INCLUDED THE ADDITION OF AN UNBONDED SLAB ON THE GRIDWORK. THE RESULTS DERIVED FROM THIS RESEARCH WERE LIMITED TO A STUDY OF LOAD DISTRIBUTION WITH ALL MEMBERS PERFORMING ELASTICALLY. THE VARIABLES WHICH WERE STUDIED WERE THE NUMBER, POSITION AND SIZE OF THE DIAPHRAGMS, AND THEIR END CONNECTIONS. THE DATA IS SHOWN IN THE FORM OF INFLUENCE LINES FOR THE PERCENT OF TOTAL BRIDGE BENDING MOMENT THAT EXISTS IN EACH STRINGER. ANALYSIS OF THE DATA INDICATES THAT WHEN THE STRINGER DESIGN CRITERION IS BASED ON MAXIMUM MOMENT, DIAPHRAGMS SHOULD BE PLACED AT THE CENTERLINE ONLY. HOWEVER, ADDITIONAL DIAPHRAGMS MIGHT BE NEEDED AS SPACING MEMBERS DURING CONSTRUCTION. EXAMINATION OF DIAPHRAGM STRESSES SHOWS THAT THE STIFFNESS OF THE DIAPHRAGM RATHER THAN ITS MOMENT CARRYING CAPACITY IS THE GOVERNING FACTOR IN THE LATERAL DISTRIBUTION OF THE LOAD. /BPR/

• Supplemental Notes:
  • Hps-hpr1/1/, BPR-7, NCHC-J, JUN64
• Corporate Authors:

  University of North Carolina, Chapel Hill

  Chapel Hill, NC  United States  27514
• Authors:
  • Bramer, C R
  • Uyanik, M E
• Publication Date: 1965-6

Subject/Index Terms

• TRT Terms: Bending moments; Bridge design; Bridge members; Bridges; Center lines; Design; Diaphragms (Engineering); Evaluation; Experiments; Field tests; Load transfer; Location; Metal bridges; Physical distribution; Slabs; Steel; Steel bridges; Stiffness; Stresses; Stringers; Structural design
• Uncontrolled Terms: Design criteria; Lateral loads
• Old TRIS Terms: Diaphragms; Placement
• Subject Areas: Bridges and other structures; Design; Freight Transportation; Highways;

Filing Info

• Accession Number: 00207734
• Record Type: Publication
• Files: TRIS
• Created Date: Oct 1 1994 12:00AM