ABSTRACT
Bridge owners are routinely faced with the challenge of rating bridges or culverts that are missing information. Concrete bridges and culverts make up the largest percentages of bridges with missing information. While some guidance is provided in the AASHTO Manual for Bridge Evaluation for load rating bridges with missing information, it is limited. Consequently, states have developed varied procedures for load rating this subset of bridges. In this investigation, U.S. concrete bridges and culverts that were rated using “engineering judgement”, per National Bridge Inventory (NBI) data, were rated using four different state procedures, those of Idaho, California, Oregon, and West Virginia. This dataset of almost 17,000 bridges and culverts were rated and compared. Results show that, on average, Results show that, on average, the inventory and operating rating factors for the almost 17,000 bridges were from 14 to 21% apart, however, the range of results is quite varied—the COV varied from 6 to 24%. The Idaho procedure, on average, is the most conservative of the four.
