Abstract
Soundproof walls are installed on railway concrete viaducts to reduce the noise from running trains. Recently, the soundproof plates made of transparent polycarbonate have been additionally installed on the present soundproof walls on concrete viaducts. However, the higher the soundproof plate is, the larger is the wind load which acts on the viaduct. Then it is almost impossible to install high soundproof plates without reinforcing the viaduct sufficiently. Therefore, we have developed new soundproof equipment which is composed of polycarbonate of 8mm in thickness for noise insulation and metal frames. The soundproof plate of this equipment is supported by rotating shafts on the both sides and fixed by magnetic force at its bottom. The plate opens in case where the wind load exceeds the threshold value of the design of the viaduct, which results in reducing the load transmitting to the viaduct to less than its design wind load. Heretofore, it was verified in a tunnel test that the plate opened as expected in the case of strong wind and reduced the wind load acting on itself. Train operators demand that the plate should close immediately after the wind weakens below a certain level. In this paper, a new closer was introduced to obtain non-linear torque to close the plate. Wind tunnel test and exposure test in a heavy storm ware carried out to confirm the effectiveness of the closer.
