LOAD RATING AND ULTIMATE CAPACITY EVALUATION OF COMPACT STEEL GIRDER BRIDGES

Slab-on-steel girder bridges are highly redundant structures and show significant redistribution capacity and a large reserve capacity in the inelastic range. To achieve consistent levels of safety over the bridge inventory, consideration should be given to the ultimate capacity of the system. First-hinge and inelastic limit rating methods for a single-span and a three-span composite bridge were examined. The rating methods were the AASHTO load factor rating maximum-strength operating level rating, the AASHTO Guide Specifications for the Strength Evaluation of Existing Steel and Concrete Bridges rating, and the single-girder and the system shakedown limit ratings. Examination of limits beyond the first hinge yielded insight into the available reserve capacity. A comparison of the methods showed that even simple-span bridges have significant reserve capacity beyond the first hinge. The additional capacity was attributed to transverse redistribution of forces. However, the total reserve capacity was not uniform for all bridges. The three-span bridge example shows that, in addition to this transverse component, longitudinal redistribution of forces adds even more to the reserve capacity. The first-hinge rating methods do not reflect the relative ultimate load-carrying capacities of one-span and multispan bridges.

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 1-7
  • Monograph Title: Steel, concrete, and wood bridges
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00711787
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Sep 25 1995 12:00AM