At one time "low" or, as generally referred to, "pony" truss bridges were popular for their economy and ease of construction. With the tremendous increase in the weights of commercial vehicles, especially after the second world war, the load carrying capacity of these bridges became suspect and many were taken out of service or replaced by modern structures. An ultimate load test carried out by the Ministry's Structural Research Section on a pony truss bridge in 1969 indicated that these bridges possess an inherent strength that far exceeds the value obtained by elementary structural theories. The complex problem of lateral buckling of truss compression chords, which in the past has led to oversimplifying assumptions resulting in underestimation of the bridge strength, has been solved by a computer program based on a modified version of Bleich's method. The program, whose validity has been checked against experimental results, is expected to provide bridge engineers with a better assessment of the load carrying capacity of pony truss bridge than has been possible in the past. Since there are several hundred existing pony truss bridges in Ontario alone, it is economically important, especially in the present inflationary financial situation, to determine the extent to which these bridges can usefully serve their purpose. /Author/

  • Corporate Authors:

    Ontario Ministry of Transportation & Communic, Can

    1201 Wilson Avenue
    Downsview, Ontario M3M 1J8,   Canada 
  • Authors:
    • Csagoly, P F
    • Bakht, B
    • Ma, A
  • Publication Date: 1975-10

Media Info

  • Features: Appendices; Figures; References;
  • Pagination: 24 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00139204
  • Record Type: Publication
  • Report/Paper Numbers: RR 199
  • Files: TRIS
  • Created Date: Sep 4 1977 12:00AM