開発途上国の未改修河川でのコーズウエーと潜り橋の実用性に関する現地資料に基づく考察

抄録

In rivers without levees mainly seen in developing countries, bridges and the embanked roads suffer from damages since embanked roads constructed on the flood plains strengthen the flood flow. This is because such bridges are constructed over only dry season’s flow width, which extends during floods. In order to prevent such disasters, length and height of bridges should be determined by design flood of larger scales. However, this may result in unreal construction cost. In such cases, bridge planning methodology that balances with financing capability is required. To present solutions to this issue, in the previous papers, authors proposed submersible bridges and causeways as realistic countermeasures rational for natural and socio-economic conditions of the developing countries. In this paper, causes of flood damages on bridges are further analyzed, and the practicability of the proposed idea is studied based on data which were obtained at the localities where the idea had been actually applied, from many regions of the world over past years.