PURPOSE: To improve noise-decreasing effect and efficiency of work execution by installing sound wave-refracting devices having a plurality of through passages, each different in length, to openings of floor slabs and to upper end of soundproof wells of an elevated structure for railway tracks or the like.
CONSTITUTION: Sound control devices 17 and 18 having a plurality of through passages 19, each of which is different in length in consecutive order, are constructed of high- density materials such as metals, inorganic materials, plastics or the like. The devices 17 are installed along openings 16 of a floor slab 14 of an elevated structure and, at the same time, the devices 18 are installed at the upper end of soundproof walls 15 and in the direction along the walls. As noises emitted from contact of rails 13 and wheels run through each of the through passages 19, lines of sound waves are refracted in the direction toward the side of bridge piers 15 and dispersion of the sound wave to the outside is curbed thereby. The sound wave control device may be constructed in a lens-like-shaped hollow structure so that the sound wave may be focused on a prescribed sphere of convergence. Thereby noise-decreasing effect can be improved, while work efficiency for installation can be improved as the device can be made compact and lightweight and available for mass procution.
NIIYAMA JUNICHI
TOMITA HISATAKA
MURASE MASANORI
IIDA KAZUYOSHI
BRIDGESTONE CORP