This report contains a description and analysis of data on precast, prestressed concrete spans. Two spans having the same type section were investigated, one span was 33 ft-6 in. in length and the other 40 ft-6 in. The spans were composed of six box beams each, 3 ft wide and 3 ft-6 in deep for a total width of deck of 18 ft. Each beam has a rectangular void. The purpose of this investigation was to determine static and dynamic strains in the beam spans over a full range of speeds by a test train. Stresses shown in the report had been calculated from the measured strains using an assumed modulus of elasticity, E equal to 5,000,000 psi for the concrete. The static and dynamic effects of a test train operating over a speed range of from 5 to 60 mph on two prestressed concrete spans were measured, and from the analysis of the test data, it can be concluded that; 1. The distribution of the live load to the six beams which comprised each span varied widely, the inside beams carrying up to three times as much load as the outside beams. This may be attributed to the extreme width of the deck, and the arrangement of the tie bars. 2. The maximum recorded live load and impact stresses in the bottom fiber were very low as compared to the calculated precompression of the bottom fibers based on Cooper's E 72 loading. 3. All maximum recorded live load plus impact stresses were lower than the calculated values based on the test locomotive loading. 4. The recorded impacts, except for a very few values for the outside beams which carried only a small proportion of the live load, were considerably lower than the values computed on the basis of the current AREA impact formula. 5. Recorded live load stresses and recorded maximum impacts were larger for cars than for locomotives. 6. For a speed range from 10 mph to 60 mph there was no appreciable increase in recorded impact.

  • Supplemental Notes:
    • Conducted under sponsorship of AREA Committee 30 - Impact and Bridge Stresses.
  • Corporate Authors:

    Association of American Railroads Research Center

    3140 South Federal Street
    Chicago, IL  United States  60616
  • Publication Date: 1966-3

Media Info

  • Features: Figures; Tables;
  • Pagination: 8 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00095871
  • Record Type: Publication
  • Source Agency: Association of American Railroads
  • Report/Paper Numbers: ER-64
  • Files: TRIS
  • Created Date: Jul 24 1975 12:00AM