Scrap Tire Culverts: Hydraulics and Design

Reusing whole scrap tires as a culvert is a cost-effective alternative to draining water from small drainage basins. The complete design of a scrap tire culvert must consider both structural and hydraulic performance. Hydraulic considerations are the focus of this report. The hydraulic capacity of a scrap tire culvert is largely affected by the limited size and the relatively rough barrel formed by scrap tires. In this analysis, the hydraulic capacities of culverts made of truck tires, at various slopes and lengths, were obtained by estimating Manning’s roughness coefficient and limiting the maximum flow depth in the culvert to 75 percent of the pipe diameter. The Manning’s roughness coefficient of a truck tire culvert was estimated to be 0.05 and 0.075, respectively, with and without sand ballast placed in the bottom of tires. The results show that a truck tire culvert can drain water up to 0.35 m3/s, and its hydraulic efficiency approaches that of conventional pipes of the same diameter when the slope is greater than 0.11 or 0.30, respectively, for culverts made of truck tires with or without sand ballast. The equivalent concrete and corrugated metal pipe sizes were obtained for corresponding flow capacities of truck tire culverts.