摘要: |
Bridges are a cultural resource that must be considered for historic significance under the Historic Preservation Act of 1966. The Virginia Transportation Research Council conducted pioneering studies of Virginia's early metal truss bridges and concrete and masonry arch bridges during the 1970s and 1980s. However, no comprehensive evaluation of nonarched concrete bridges in Virginia had been undertaken, and it had become standard practice to evaluate these bridges on a case-by-case basis as projects arose that might affect them. Most of these studies were done by outside consultants, a time-consuming and expensive method. The Virginia Transportation Research Council's "Survey of Non-Arched Historic Concrete Bridges in Virginia Constructed Prior to 1950" has rectified the lack of information and analysis of these bridges (1950 was chosen as a cutoff date because structures generally must be at least 50 years old to be considered historically significant under National Register criteria). A field survey and data tabulation were completed, and criteria for the evaluation of historic significance were developed and applied to the results of the survey and analysis. Of 1,420 nonarched concrete bridges built before 1950, fewer than a dozen were found to be individually eligible for the National Register of Historic Places. The project identified Virginia's few significant bridges of this type for appropriate management, and cleared more than 1,400 bridges, the great majority of Virginia's nonarched concrete bridges, for maintenance and upgrade as needed. It is estimated that this project has already saved the Virginia Department of Transportation $500,000 and eliminated a typical 3- to 4-month delay for each project. Projected savings arising from this project are estimated at approximately $2.5 million over the next 10 years. |