Past observations have indicated that rusting has been rather prevalent in the large, un-paved metal drainage structures most of which have been installed since the opening of the Kentucky Rural Secondary Program in 1949. Since all of these structures are relatively new, and since rusting in any form can be considered a threat to the life of a structure, the Chief Engineer's Office, in 1954, requested that a study be made to determine the over-all frequency possible causes, and individual seriousness of this condition.

Altogether, a total of 86 of these un-paved structures were inspected. Although it would have been virtually impossible to inspect every one in the state, a pattern was followed which was believed to provide a representative and sufficiently large sampling. This pattern, by counties and by number of structures inspected per county, is shown in Fig. 1. Structures were located for inspection by use of the R. S. Final Estimate Forms.

Almost all of the structures inspected showed evidence of rusting in one form or another. Moverover, the condition was found in areas where testing for acidity, using methyl red and methyl orange pH indicators, indicated no serious acidity of the water, sometimes heretofore thought to be prerequisite to rusting.

A number of arches were found to be in need of immediate attention, and it was noted that the life of many others could undoubtedly be extended by a protective treatment of the inverts.

Report Date


Report Number

No. 121

Digital Object Identifier