Dynamic Behavior of Ribbon Floating Bridges: Analytical and Experimental Studies

Floating bridges are economical means for crossing water bodies, especially in times of emergency or war. A special type of floating bridge, a ribbon pontoon floating bridge, is designed, built, and stocked by the military and emergency management organizations to be deployed in times of need. Lightweight and quickly erected, such bridges use the buoyancy of water to support their weight and imposed traffic loads. With increasing vehicular weights and the need for fast traversing times, analytical tools capable of designing and analyzing floating bridges are necessary. This development is ideal for optimizing vehicle weights and spacing to achieve greater economic efficiency. An analytical and experimental research program designed to study the dynamic behavior of ribbon pontoon floating bridges under two-axle vehicular loading is presented. This analytical method yielded maximum bridge displacements comparable to the experimental results. In most cases, analytical results were higher than experimental results; this difference provided a level of conservatism for design. Midspan displacements were accurately predicted as the vehicle traversed the floating bridge. However, at heavier vehicle weights, the analytical model failed to predict midspan displacement accurately at axle locations beyond midspan.