Comparative Dynamic Load Effects of Tracked and Wheeled Military Vehicles on Bridges

Abstract

The perceived and observed differences in the dynamic behavior between wheeled and tracked military vehicles should be considered when applying appropriate dynamic load effect values for bridge design and assessment. Based on available test data, tracked military vehicles appear to impose less severe dynamic load effects when compared with wheeled vehicles under similar crossing conditions. In exploring a range of crossing conditions, a review of test data was used to make a general comparison of the dynamic loading amplification between tracked and wheeled military vehicles. To expand the range of crossing conditions tested for an instrumented bridge, additional data were collected for an artificially induced roughness of the bridge surface. By combining the test results from previous studies with the results from this testing program, the relative dynamic loading amplification between tracked and wheeled military vehicles can be quantified for situations with similar crossing conditions. Given this comparison, it may be appropriate to use a dynamic load allowance (DLA) of as low as 70% of the code-specified DLA for wheeled vehicles when evaluating the capacity of bridges subjected to military tracked traffic. This is especially relevant when considering maneuver options for main battle tanks during military combat operations.