Dynamic Load Effects of Wheeled and Tracked Military Vehicles on a Steel Girder Composite Bridge

Abstract

The perceived and observed differences in the dynamic behavior between wheeled and tracked military vehicles should be accounted for in the application of appropriate dynamic load effect values for bridge design and assessment. No current North American bridge design or assessment code provides guidance on methods to differentiate between the dynamic loading effects of wheeled and tracked vehicles. Civilian codes and the Military Load Classification (MLC) system used by the North Atlantic Treaty Organization (NATO) typically use the same dynamic loading effects values for both wheeled and tracked vehicles that can significantly impact and limit the mobility of tracked vehicles. Bridge load testing was carried out to compare the dynamic loading effects between three wheeled military vehicles and a main battle tank, Leopard 2. Results indicate that it may be appropriate to reduce the dynamic load allowance (DLA) used for military tracked vehicles by one-third of that used for military wheeled vehicle analysis. A review of several nations' DLA values was carried out, and application of a reduced DLA for tracked vehicles could result in an increase to the predicted bridge capacity of 5%–13% for tracked vehicles.