Vehicle–Track–Bridge Interaction Modeling and Validation for Short Span Railway Bridges

Railway bridges are critical in the transportation network and vital to the profitability of the industry. Thousands of U.S. bridge spans of more than 50 years of age are still in service. Transportation Technology Center, Inc.’s current work under the Association of American Railroads Strategic Research Initiatives Program on bridge life extension focuses on the effects of increased axle loads, on extending the safe service life of existing steel bridge spans, and on onboard inspection of bridge structural integrity. The program includes various tests at the Bridge Deflection Test Facility (BDTF) at the Transportation Technology Center, Pueblo, Colorado, as well as vehicle–track–bridge interaction modeling. This paper presents simulation and test results of a freight car and locomotive running on a railway bridge located at the BDTF. Simulation and test results of an onboard system installed on an instrumented freight car indicated that it is a useful tool for identifying some bridge condition issues. The BDTF provides adjustable bridge strength and geometry conditions. Various tests were conducted on the BDTF to investigate the potential for using onboard technology to detect bridge impairment or changes in bridge behavior. Test results were used to validate the NUCARS three-layer track model of the BDTF. Experimental and analytical case studies were conducted to develop onboard systems for dynamic inspection of bridges under varying loads.