Numerical and Experimental Investigation of Ribbon Floating Bridges

This study investigates the dynamic behaviour of a hinge-connected ribbon floating bridge. A finite element program was used to simulate the displacement of the floating bridge when subjected to consecutive vehicles of varying weight, speed, and inter-vehicle spacing. A 1/25-scale experimental model was also constructed to physically examine bridge behaviour. For two vehicle crossings, results showed that the magnitude of the first peak vertical midpoint displacement primarily depended on vehicle speed, while the second peak depended on both vehicle speed and spacing. A Speed Ratio was defined to relate the frequency of vehicle-induced loads to the bridge frequency of vibration, and a resulting analytical equation proposed calculate the maximum displacement that would occur with vehicle weight increase at specified speeds. The bridge capacity at varying speeds and inter-vehicle spacing were determined numerically. For maximum vehicle-crossing capacity, inter-vehicle spacings were proposed for each specified vehicle speed to minimize vertical bridge displacements.