Subject and Keywords:
Load rating of corrugated metal (CMP) culverts with very low soil cover is poorly defined by AASHTO Load and Resistance Factor Rating (LRFR) procedures. Because of this the Ohio Department of Transportation (ODOT) developed a load rating procedure based on the AASHTO LRFD Design Specifications, National Corrugated Steel Pipe Association Design Data Sheet 19, and the stability method proposed by Galambos. A research study was recently completed in Ohio to evaluate the current load rating method, employed by ODOT, for load-rating corrugated metal culverts installed with soil cover less than the minimum specified by current LRFD specifications. Six corrugated metal culverts were fully instrumented and subjected to a series of static and dynamic live load tests. The field test data were analyzed to understand the response of shallow-installation CMP culverts to live loading. The sensor readings were also used to compute the thrust response of the culverts. Then, the current ODOT load-rating procedure using the field applied live load was utilized to calculate wall thrust. The field determined wall thrusts were then compared to the calculated wall thrusts. It was observed that the current ODOT procedure is very conservative, as the calculated thrust values were much higher than the field values for five of the six test structures.