EXPERIMENTAL STUDY ON EFFECT OF STONE ARCH BRIDGE ON FLOOD FLOW AND ITS STABILITY AGAINST FLOOD PRESSURE

Abstract

The region of Nagasaki, Kyushu, Japan was inundated by heavy rainfall on the 23rd of July, 1982, and water flow of the River Nakajima and other rivers increased remarkably in this area. Many rivers in Kyushu are spanned by stone arch bridges.To study on the effect of flood flow on a stone arch bridge and to measure fluid pressure that may damage the bridge, a solid model of Fukuro bridge and a model stone masonry arch were prepared in the experimental water channel at Nagasaki University.The experiment was performed for two cases: in the first case the model stone arch was set in the water channel and in the second case no model arch was used. For each case, the hydraulic data and the resultant drag and down-pull forces working on the arch stones, were measured. Using the external forces obtained in the both tests, the stability of the stone arch bridge was calculated for the flood flow. The calculation confirmed that the arch stones of the Fukuro bridge could withstand the flood.