Federal Highway Administration

The National Bridge Inventory Database (NBI) is the most extensive repository of data on highway bridges in the United States. Initiated in 1972, this database now contains detailed historical data on over 600,000 bridges for a span of 26 years. The archived and current NBI files contain more than 6.2 billion bytes of data. To efficiently utilize this information for research and analysis, the authors investigated and developed several different relational database management approaches and data warehousing techniques. From the resulting system, data mining methods were used to efficiently access this data and extract information on the Nation’s highway bridges. This has resulted in a significantly better understanding of the bridge inventory. Key descriptive statistical summaries of the NBI resulting from this work are presented. Although the NBI, in itself, is a tremendous resource, the true power of data mining methods was not realized until the data inherent in the NBI was expanded by implementing a spatial relationship capability utilizing a geographic information system (GIS). This facilitated extensive visualization of geographic patterns in the NBI data, several examples of which ar