ANALYSIS AND TESTING OF A TRAPEZOIDAL BOX GIRDER BRIDGE

Bridge construction using open steel box girders and a concrete deck slab acting composite is aesthetically pleasing and ideally suited for grade separations and river crossings for spans varying between 21 m and 110 m (70 ft. and 360 ft.). Current design specifications for this construction, however, are considered to be incomplete and do not provide sufficient guidance during construction. In a number of cases, due to lack of bracings and/or diaphragms, excessive displacements have occurred during construction. To clarify this problem, a typical, single span, 2-lane bridge was extensively instrumented and tested. The purposes of the testing program was to investigate the behaviour of a torsionally stiff bridge during and after construction and to compare the experimental data with analytical results. The concrete deck, which was constructed with 0.3% isotropic reinforcement to comply with the AASHTO Specifications, was also monitored. Test data consisted of structural and reinforcing steel strains, deflections, reactions for construction, and live load and temperature effects. The experimental deck was constructed in two stages. A preliminary review of the data indicated that, for this bridge geometry, construction effects were within the predicted values as no excessive deflections or strains were observed. The concrete deck with the dramatically reduced reinforcement was adequate for modern highway traffic provided sufficient diaphragms were present. The overall structural behaviour can be accurately predicted by analysis and, with diaphragms present, can be analyzed by beam theory and proper load distribution factors.

Media Info

  • Media Type: Print
  • Features: Figures; Photos; References; Tables;
  • Pagination: pp 81-89
  • Monograph Title: Bridge Engineering. Volume 2
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00183783
  • Record Type: Publication
  • ISBN: 0309026970
  • Files: TRIS, TRB
  • Created Date: Dec 12 1978 12:00AM