EXPERIMENTAL STUDY ON EFFCTS OF WOODY DEBRIS LENGTH ON DRIFTWOOD ACCUMULATION AT BRIDGE

Abstract

 The driftwood accumulation tests at a single pier bridge were conducted. We evaluated the critical condituion for driftwood blocking by changing the woody debris length. We measured the backwater rise during the driftwood accumulation tests and evaluated the blocking ratio of the woody debris jam. The inclination angle of trapped log relative to the flow direction was measured using a camera placed above the flume and examined the effect of the wood debris length on the driftwood carper shape. During the experimets, the force exerted on the bridge increases due to the driftwood accumulation. We also measured the force exterted on the bridge using a force gage.