The dynamic behavior of an armored vehicle launched Bridge

This paper reports the findings of a modal test targeted to study the dynamic behavior of an Armored Vehicle Launched Bridge (AVLB). Forced vibration tests using shaker excitation were used to excite the vertical bending modes of the AVLB while 120 accelerometers were used to measure the bridge response in the vertical direction. The results indicate that the bridges' four girders behave like lightly damped and coupled girders that exhibit complex vibration modes. An additional modal test was also conducted to study the dynamic behavior of the AVLB with one of the pins from one of the girders removed. The results from this test show significant stress redistribution and a different dynamic behavior. This paper also reports AVLB testing under both simply supported conditions and free-free conditions. The results were also compared to finite element testing results.