LOAD DISTRIBUTION IN A COMPOSITE STEEL BOX GIRDER BRIDGE

FIELD TESTS WERE PERFORMED TO ASSESS THE BEHAVIOR OF A STEEL BOX GIRDER BRIDGE HAVING A COMPOSITE, CONCRETE, ROADWAY DECK SLAB. THE STRUCTURE WAS INSTRUMENTED AT ONE MIDSPAN CROSS-SECTION AND A SECTION NEAR THE SUPPORT OF SPAN 20, ONE OF THE SIMPLE APPROACH SPANS, TO PERMIT STUDIES OF BENDING AND SHEAR STRAIN DISTRIBUTIONS. LIVE LOAD WAS APPLIED WITH A SIMULATED AASHO DESIGN TRUCK AND A DOUBLE GOOSE-NECK, LOWBED HAULER BALLASTED TO A GROSS LOAD OF 220,000 POUNDS. THEORETICAL ANALYSES WERE PERFORMED WITH A FINITE ELEMENT PROGRAM CALLED FINPLA. LIVE LOAD MEMBRANE STRAINS WERE ACCURATELY PREDICTED BY THE PROGRAM, BUT FIBER STRAINS, ESPECIALLY IN THE TRANSVERSE DIRECTION, WERE GREATLY INFLUENCED BY PLATE WARPAGE AND INITIAL, LOCAL, DEAD LOAD DEFLECTIONS. MEASURED DEAD LOAD STRAINS WERE LARGER THAN THEORETICAL AND MAY HAVE BEEN INFLUENCED IN SOME DEGREE BY FALSEWORK. DEAD AND LIVE LOAD DEFLECTIONS WERE APPROXIMATED BY THE THEORETICAL ANALYSIS, BUT THE PROGRAM OVER-ESTIMATED THE TORSIONAL STIFFNESS OF THE SUPERSTRUCTURE. LIVE LOAD STRAINS WERE NEGLIGIBLY CHANGED BY THE ADDITION OF CONCRETE BARRIER RAILINGS. LIVE LOAD SHEAR STRESSES NEAR THE SUPPORT WERE CORRECTLY PREDICTED BY THE PROGRAM ON THE UNLOADED SIDE, BUT THE MEASURED STRESSES DIFFERED IN MAGNITUDE AND VERTICAL DISTRIBUTION ALONG THE WEB FROM THOSE PREDICTED BY THE PROGRAM ON THE LOADED SIDE; HOWEVER, THE STRUCTURE HAD BEEN MATHEMATICALLY MODELLED FOR ACCURATE PREDICTION ON MIDSPAN STRAINS RATHER THAN SHEAR STRESSES. /FHWA/

• Corporate Authors:

  California Department of Transportation

  Bridge Department, P.O. Box 1499
  Sacramento, CA  United States  95807

  California Department of Public Works

  1120 N Street
  Sacramento, CA  United States  95814

  Calif Business & Transportation Agency

  ,    
• Authors:
  • Davis, R E
  • Castleton, G A
• Publication Date: 1973-6

Subject/Index Terms

• TRT Terms: Bending; Box girders; Bridges; Composite construction; Computer programs; Deflection; Deformation curve; Field tests; Finite element method; Forecasting; Load transfer; Mathematical models; Slabs; Theory
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00208125
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: Res Rpt
• Files: TRIS, USDOT, STATEDOT
• Created Date: Jun 5 1974 12:00AM