マンホール鉄ふた模様におけるすべり抵抗係数の影響因子の研究

摘要

濡れたマンホール鉄ふた上では二輪車のスリップ転倒事故が発生し易いとされ，多くのマンホーrnル鉄ふたの性能仕様書にはスリップ防止性能が要求されている。本研究では，マンホール鉄ふた用スリップ防止性能試験装置を用い，マンホール鉄ふたの表面模様がスリップ防止性能に及ぼす影響度の定量化を行った。従来から経験的に，独立した小突起がスリップ防止に有効であると言われていた。本研究ではデザインが異なる数種類の鉄ふたの測定を行い，それぞれの特徴的模様が及ぼす影響を検討し，マンホール鉄ふたにおけるスリップ防止性能の影響因子の研究を行った。さらに，多くの自治体で採用されているデザインマンホール鉄ふたにおいても，スリップ防止性能を向上させる研究も行い，デザインマンホール鉄ふたであってもすべり抵抗係数向上の可能性が確認された。%It has been reported that it is easy for motorcycles to slip on wet manhole covers, thus causing accidents, and in many property specifications for manhole covers, slip prevention capability is required. In this study, a slip prevention capability testing device for manhole covers was used to quantify the influence which a pattern on the upper surface of a manhole cover has on its slip prevention capability. According to reports, experience shows that small independent projections distributed on the surface are effective in preventing slips. In this study, several types of manhole covers with different designs were measured, the influence of each of these distinctive patterns was considered, and the factors influencing the slip prevention capability of manhole covers were investigated. Further, research to improve the slip prevention capability of manhole covers with designs adopted by many local governments was carried out, and it was confirmed that improvement of the slip resistance coefficients of these manhole covers with specified designs also is possible.