EFFECT OF TRUCKS UPON A FEW BRIDGE FLOORS IN IOWA IN 1922 AND IN 1948

INVESTIGATIONS FOR IMPACT WERE MADE DURING THE SUMMERS OF 1922 TO 1925 WHEN THE TRUCKS WERE ENTIRELY DIFFERENT FROM THOSE USED IN 1948. VARIOUS FACTORS DISCUSSED ARE: (1) THE RELATION OF THE FORCE OF A WHEEL BLOW UPON PAVEMENT TO THAT OF A SIMILAR BLOW UPON A MORE FLEXIBLE BRIDGE FLOOR AND (2) THE RELATION OF THE STRESS WHICH IS DEVELOPED IN THE STRINGERS AND FLOOR BEAMS BY A DYNAMIC BLOW AND BY A STATIC LOAD OF THE SAME WEIGHT AS THE FORCE OF THE BLOW. INITIAL STATIC READINGS FOR DEFORMATION WERE TAKEN PRIMARILY AS A BASIS FOR DYNAMIC READINGS. THESE READINGS SHOWED THE COMPARATIVE DEFORMATION OF THE VARIOUS LONGITUDINAL STRINGERS, OR IN OTHER WORDS, THE DISTRIBUTION OF LOAD AMONG THE STRINGERS. THEY ALSO POINTED DEFINITELY TO THE ACTION OF THE REINFORCED-CONCRETE FLOOR SLAB IN RELIEVING THE STEEL STRINGERS FROM MUCH OF THE STRESS WHICH WOULD HAVE BEEN DEVELOPED IF THEY ALONE HAD BEEN CARRYING ALL THE LOAD. BRIEF EXPLORATORY RESEARCH WAS UNDERTAKEN IN 1948 AS A MEANS OF OBSERVING WHETHER THE COMPOSITE ACTION BETWEEN THE CONCRETE FLOOR SLAB AND THE STEEL STRINGERS HAD REMAINED AFTER 28 YEARS OF SERVICE. THE RESULTS INDICATE THAT IN A 34-FT. I-BEAM SPAN THE COMPOSITE ACTION WAS STILL EFFECTIVE; AND THAT IN A PANEL OF A TRUSS BRIDGE, ALTHOUGH THE BOND WAS APPARENTLY BROKEN, THE DEFORMATIONS AND RESULTING STRESSES WERE LESS THAN IF THE STEEL ALONE WAS SUPPORTING THE LOAD. THE RESULTS ALSO INDICATE THAT IN THE 20'S AND IN 1948 THE LOAD TRANSFERRED TO THE MOST LOADED STRINGER WAS (FOR THESE CLOSELY SPACED STRINGERS) SOMEWHAT IN LINE WITH THE PROVISIONS OF THE AASHO SPECIFICATION. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrbresearchrpts/1952/14B-001.pdf
• Supplemental Notes:
  • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Corporate Authors:

  Highway Research Board (HRB)

  Washington, DC   
• Authors:
  • Fuller, Almon H
• Conference:
  • Thirty-First Annual Meeting of the Highway Research Board
• Publication Date: 1952

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 9p
• Monograph Title: Distribution of load stresses in highway bridges
• Serial:
  • Highway Research Board Research Reports
  • Issue Number: 14B
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Axle load force; Bridge decks; Bridges; Composite structures; Dynamic loads; Stringers; Trucks; Wheel loads
• Uncontrolled Terms: Composite bridges
• Old TRIS Terms: Truck effects (Bridges)
• Subject Areas: Bridges and other structures; Highways; Motor Carriers;

Filing Info

• Accession Number: 00209597
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: May 22 1972 12:00AM