A three span (20'-25'-20') reinforced concrete slab bridge was loaded to its collapse load. The slab was 32' wide and 12" thick, however, there was a 2'-10" wide by 10" thick curb cast on each edge of the slab. Loading consisted of a line load across the midspan. This loading was produced by hydraulic rams which were reacted by overhead steel beams that were attached to the piers with tension rods through the slab. The load was increased by intervals until collapse. At each load interval measurements were made on deflection and strains on the concrete surface. Strength of the concrete and steel materials were in excess of the design minimum values with an average 6865 psi cylinder strength compared to a design value of 3000 psi compared to a design value of 40,000 psi. The results indicated: (a) measured concrete stresses were much below the calculated values, (b) the load causing first permanent set was accurately predicted by calculating the yield moment in the slab, (c) the collapse load was accurately predicted by considering the formation of yield moments along the centerline and over the piers of the bridge for a channel section loaded about its weak axis, and (d) based on the center span line load it would take eight H20S16 trucks placed in the center of the bridge to cause any permanent deflection and twenty H20A16 trucks to cause the bridge to collapse.

  • Supplemental Notes:
    • Sponsored by North Dakota State Highway Department in cooperation with Federal Highway Administration.
  • Corporate Authors:

    North Dakota State University, Fargo

    Engineering Experiment Station
    Fargo, ND  United States  58105
  • Publication Date: 1974-12-28

Media Info

  • Pagination: 48 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00084697
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: Final Rpt.
  • Contract Numbers: (1)72
  • Files: TRIS, USDOT
  • Created Date: Jul 2 1975 12:00AM