Effective Area of Bridge Pier to Small Boat

Abstract

The width of effective area of bridge pier, which is an important factor to calculate possible capacity of a fair-way, is obtained for small boats from observation, made on the Sumida River, Tokyo. Statistical manipulation is made for frequency data of separation of boats and the edge of bridge Pier. The width of effective area is obtained to be about 2a+3Lpp for small boats. Such value for tnain barges is 2a+80m, where 2a is the width of bridge Pier. The speed of boats under the bridge (Eitaibasi) shows little change compared with that in ordinary condition.