Pattern Design of Manhole Cover and Its Influence on Skid Resistance

The number of manholes appeared on urban streets has increased significantly in the last decade in Taiwan. Due to the material characteristic, manhole surface is rather slippery in the raining days if no good skid resistance design is provided. Based on the findings of the literature review, sample collection of the Taiwan existing manhole pattern, and skid tests on all collected manhole surfaces, this study created a series of experimental design of patterns and conducted the British Pendulum Tester and Dynamic Friction Tester tests on the specimens. The design factors of the pattern include bump spacing, bump area, bump shape, bump height, and the bump alignment. Dozens of specimens were designed, cast, and tested; and it was found that the manhole surface pattern with the following characteristics gives the best performance: spacing between bumps- 15 mm; shape and area of each bump- 15 mm x 15 mm square; minimum height of bump: 3mm; alignment of the bumps: chessboard. Full scale manhole covers were cast and tested. Manhole cover design with chessboard pattern indeed can provide a significant improvement in skid resistance, increases of 11.8% of BPTwet value and 47% of DFT60 value, compared with the ones available in the market. Micro-texture and macro-texture are two major factors that affect skid resistance of a surface. On a road surface, micro-texture is a function of time (wearing). Testing only new manhole cover may not represent the long term effect of the new design.

並列關鍵字

British pendulum tester ； Dynamic friction tester ； Nodular graphite cast-iron manhole cover ； Skid resistance

參考文獻

Fwa, T.F., Choo, Y.S., Liu, Y. (2003). Effective of aggregate spacing on skid resistance of asphalt pavement, Journal of Transportation Engineering, 129(4), pp. 420-426.

Smartstream Technology Pty Ltd, (2009). http://www.smartstream.net.au/