Abstract:
Sharp increases in prices and a concurrent decline in highway revenues have forced a re-evaluation of highway projects. Most seriously affected are the old bridges since, unlike the rest of the highway, their life cannot be indefinitely extended by maintenance. A national bridge survey reveals that 105,000 bridges in the U.S. are structurally deficient and/or functionally obsolete and 72,000 of these are on roads that are not on the federal-aid system. The needs on our low-volume roadway system far exceed program funds available. The potential economies suggested in this paper will hopefully lead to better utilization of the funds available. This paper investigates the economics of low-volume structures. It discusses the most economical bridge types being constructed in the Northwest. Although, not primarily addressed to the hydraulics involved in stream crossings, the paper discusses some of the hydraulic considerations that should be made. Attention is directed to actual practice of agencies constructing bridges on low-volume roads. The three principal structural materials of concrete, timber, and steel are discussed. Certain structural details are suggested for economy, as well as structural types. The comments and recommendations contained in this paper are based on a survey made in the Northwestern United States. /Author/
Supplemental Notes:
This paper appeared in Transportation Research Record No. 665, Bridge Engineering, Volume 2. Proceeding of a conference conducted by the Transportation Research Board, September 25-27, 1978.
