This article notes the present day trend to concentrate attention on short-term objectives in bridge design, and points out that while least first cost is desirable, long useful life should be the important long-term objective. Today's design specifications are geared to 'efficient' designs interpreted as least first cost. This means the design primarily provides sufficient initial strength to resist static design loads. Design codes should require consideration of endurability, inspectability, maintainability, reliability, and resistance to water, corrosion, temperature cycles and neglect. There should be no debate on how much further safety margins can be reduced, but rather how much safety margins should be increased. It is also noted that design live loadings for long-span bridges are higher than the actual loads, and concentrated design live loading for short-span bridges are lower than the actual loads. However, reduction in long-span bridge design loadings is not advocated. It is suggested that the alternative military loading specified for interstate and defence highways be extended to all new bridges. A better standard loading more representative of heavy commercial trucks might be developed. The concept of alternative designs is discussed, as well as the use of concrete box girder bridges in the United States.

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Filing Info

  • Accession Number: 00492206
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 31 1990 12:00AM