ABSTRACT
The Federal Highway Administration of the United States uses its National Bridge Investment Analysis System (NBIAS) to develop needs estimates and report on the conditions and performance of the nation’s 600,000 bridges and culverts. The system’s deterioration model was recently updated to be consistent with the most recent bridge element inspection standards. A data set containing nearly 3 million element inspection records was stratified into nine climate zones according to average temperatures and moisture in each county of the United States. Algebraic methods developed in research for Florida and Virginia were used to process the element inspection data into transition probability matrices. The resulting models were then transformed for compatibility with the latest inspection manuals used in federal bridge condition reporting requirements. The product represents the first time there has been a true nationwide element level deterioration model for bridges in the United States.
