At one time, low or pony truss bridges were popular for their economy and ease of construction. With the tremendous increase in commercial vehicle weights, especially after World War II, 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 Structural Research Section of the Ontario Ministry of Transportation and Communications on a pony truss bridge in 1969 indicated that these bridges posses an inherent strength that far exceeds the value predicted 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, will provide bridge engineers with a better assessment of the load-carrying capacity of pony truss bridges than has been possible in the past. Since there are several hundred pony truss bridges in Ontario alone, it is economically important to determine the extent to which these bridges can usefully serve their purpose. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; Photos; References;
  • Pagination: pp 14-18
  • Monograph Title: Bridge design, testing, and evaluation
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00157808
  • Record Type: Publication
  • ISBN: 0309025826
  • Files: TRIS, TRB
  • Created Date: Sep 28 1977 12:00AM