Separate analyses of reinforced concrete pipe durability data collected by the Ohio Department of Transportation were conducted by the Ohio Department of Transportation and another research agency. There was a large discrepancy in the service life predicted for culverts installed in nonacidic sites between the two models. This study was initiated to establish which model was the most accurate. An inventory of older reinforced concrete pipe installations was compiled. The age of many of these culverts approached the very conservative service life predicted by the linear model developed by the other agency. The total number of 196 culverts inspected included 70 culverts installed before 1940, 89 culverts installed from 1940 to 1949, and 37 culverts installed from 1950 to 1969. The culverts were evaluated using a revised, more detailed rating system and predicted service lives extrapolated from the rating and age at the time of inspection. It was found that the linear model significantly underpredicted service life of reinforced concrete pipe for a flow pH range above 4.5 and that the Ohio Department of Transportation model provided a reasonable estimate of projected service life for the entire pH range studied.

In 1982, the Ohio Department of Transportation (ODOT) published a comprehensive research report (J) that provided information on the durability of various culvert materials. As part of this report, predictive equations for the service life of reinforced concrete pipe culverts were presented. These equations were developed from data collected in 1972 at 545 concrete pipe culvert sites throughout Ohio. These sites encompassed a wide range of topography and environmental conditions. The condition of the concrete pipe culverts was evaluated by means of the following visual rating system: