National Bridge Inventory
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The National Bridge Inventory (NBI) is a database, compiled by the Federal Highway Administration, with information on all bridges and tunnels in the United States that have roads passing above or below. This is similar to the grade crossing identifier number database compiled by the Federal Railroad Administration which identifies all railroad crossings. This bridge information includes the design of the bridge and the dimensions of the usable portion. The data is often used to analyze bridges and judge their conditions. The bridge inventory is developed with the purpose of having a unified database for bridges, including identification information, bridge types and specifications, operational conditions, bridge data including geometric data and functional description, inspection data, etc.
[edit] NBI components
Identification information addresses the bridge location uniquely and classifies the type of the routes carried out on and/or under the structure and locates the bridge within the spatial location. Each bridge is given a number by the highway department of the respective state or the agency that maintains the bridge. The method of assigning numbers differs from one state to the next, but provides a unique number for each bridge in the state.
The bridge inventory is developed for having a unified database for bridges including the identification information, bridge types and specifications, operational conditions, and bridge data including geometric data, functional description, inspection data, etc. Identification information addresses the bridge location uniquely and classifies the type of the routes carried out on and/or under the structure and locates the bridge within the spatial location. Bridge type and specifications classify the type of the bridge. This part provides defined standard categories for classification of the bridges. It also identifies the material of the bridge components, deck and deck surface. Operational conditions provide information about the age of the structure as well as construction year, rehabilitation year, type of services and traffic carried over and/or under the structure number of the lanes over and/or under the bridges, average daily traffic, average daily truck traffic and information regarding to bypass, detours. Furthermore, the bridge inventory contains information regarding to inspection data, ratings assigned by inspectors and appraisal results.
[edit] Issues and usage
The NBI was subjected to scrutiny and questions, after new actions revealed it might be outdated or inaccurate. Federal officials attempted to order emergency inspections of all steel truss bridges after a major bridge collapse in Minneapolis in 2007. However, it was found that many records within the NBI were inaccurate or out of date. [1]
[edit] External links
- msnbc.com's Bridge Tracker interactive map based on the newest National Bridge Inventory
- msnbc.com investigation: Late inspections of bridges put travelers at risk
- National Bridge Inventory (Data available in ASCII)
- National Bridge Structural Deficiency Data by State/Year Built (Data Available in Excel)
- National Bridge Inventory search
- Navigating the National Bridge Inventory
- ^ Bridge collapse revealed holes in federal data By Bill Dedman, msnbc.com, Friday, August 1, 2008.
