Institute of Fundamental Technological Research

Emergency bridges are used to restore the lifeline of damaged bridges after
disasters. However, the design specification of existing emergency bridges do not afford rapid
bridging. Therefore, a trial deployable bridge (Scissors Bridge) using a scissors structure that
folds compactly has been experimentally produced. But, the assembly process for the bridge has
not been considered and there are no practical design examples or design methods for scissors
bridges. In this paper, as for existing bridges, we established a design method of scissors bridges
when considering the live load. In addition, a general-purpose member cross-sectional dimension
optimization method, aimed at minimizing weight, was developed and proposed. Considering
the problem of insufficient strength of the scissors bridge, the optimum reinforcing pattern
and its cross-sectional dimensions were determined through two methods of reinforcement and
optimization of the cross-sectional dimension of the member. Finally, a trial of practical design
calculation was performed using the results of the study to determine whether a scissors bridge
satisfying the standard of the Specifications for Highway Bridges can be designed.