STUDY ON TRAP OF DRIFT WOOD AND LONGITUDINAL PROFILE OF WATER LEVEL IN A BRIDGE AND A MEASURE FOR DRIFT WOOD

Abstract

Blockages of drift woods can seriously increase the danger of flood events. However, the mechanisms of drift wood capture process are hardly studied and therefore, the possible countermeasures are not taken in the design of bridges. The aim of this study is to understand the basic mechanisms of drift wood capture process and water surface profile variations before and after the drift wood captures. Laboratory experiments with a model bridge in an open channel was carried out for that purpose. It was concluded that the number of driftwoods captured in the bridge has high correlation with increase of the water surface in upstream of the bridge. Water surface profiles due to driftwoods captured in the bridge seem to be intermediate between a sluice gate and radial gate.