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66 CHAPTER 4 Data Sources for NBMD NBMD collects data on bridge inventory, bridge conditions DOTs perform bridge maintenance with DOT crews and and bridge maintenance work. Sources for bridge inventory with contractors. Often, crews perform maintenance of lesser and condition data are standardized both by regulation and by cost or duration. Larger projects and longer durations are common use of the Pontis bridge management system. Main- executed through contracts. The two types of work use differ- tenance data formats, field names and content vary among ent data reporting systems. U.S. state DOTs. Crew work is reported though systems that are variously identified as crew-card, day-card, or work order systems. The usual record is a report for crew activities for one day. The Bridge Inventory Data record, typically, will contain a bridge ID, a date, a work activ- Bridge inventory data are standardized as the content and ity, and some information on costs. Costs may be presented format of the NBI Standards. Inventory data are available from as itemized lists of the equipment, materials, and personnel the U.S. FHWA website and also from the bridge and roadway used at the project, or only the hours for labor, or only as tables of the Pontis bridge database. The data sources, NBI overall costs. Expenditures are reported. Production, often, is and Pontis, are equally convenient for collection of bridge not. These are systems adapted to accounting for DOT bud- inventory data. gets for labor, materials, fleet equipment, etc. Contract work presents a different type of data record. Data for contracts are presented as sets of bid items. Poten- Bridge Condition Data tially, this is a great level of detail in work, and precise infor- mation on costs. Moreover, direct costs for materials and Bridge condition data, like inventory data, are standardized. installations can be separated from indirect costs for mobi- The NBI record contains condition ratings for deck, super- lization and traffic control. A common limitation is that con- structure, substructure, channel and culvert, as well as appraisal tracts cover all site, pavement, and bridge work required for ratings for bridge geometry, alignment, and railings. an overall project; bridge repairs are one part of a larger proj- Many DOTs collect element-level condition data com- ect. As a result, the identification of the bridge work among a patible with the Pontis bridge management system. State complete list of bid items, and the allocations of some quan- DOTs modify or add some bridge elements, and may mod- tities within bid items that provide for both bridge work and ify condition states. The general format, though, is uniform pavement work, is not apparent from the public records. That among DOTs. is, the list of bid items does not offer sufficient information to isolate bridge work quantities and costs. Bridge Maintenance Data Bridge staff at DOTs tracks contract maintenance on bridges. Many DOTs keep spreadsheets that list bridges, the Bridge maintenance data are not standardized. There has contracts that deliver work on bridges, and the cost alloca- been no federal regulation and no national-level development tions to bridge work. In addition, the type of work, and year of systems for bridge maintenance identification, recording, of work are recorded. NCHRP Project 14-15 uses the bridge and reporting. There is no dominant software package for work spreadsheet provided by Michigan DOT in preparation reporting maintenance activities and accomplishments. of the Michigan dataset for NBMD.