Consider a rough asphalt roadway with 17 cm curbs and one 3.75 m lane in each direction and a 1.45 m shoulder on each side. The road has a longitudinal slope of 0.75% and is crowned in the center with a transverse slope of 2.25%. The local ordinance requires no ponding in the roadway (only on the shoulders) for a storm with an intensity of 90 mm/hr. A) Determine the maximum distance between curb inlets.

Question

Kallie Mathews

Physics

23 September, 21:16

Consider a rough asphalt roadway with 17 cm curbs and one 3.75 m lane in each direction and a 1.45 m shoulder on each side. The road has a longitudinal slope of 0.75% and is crowned in the center with a transverse slope of 2.25%. The local ordinance requires no ponding in the roadway (only on the shoulders) for a storm with an intensity of 90 mm/hr. A) Determine the maximum distance between curb inlets.

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Jace Kline · Answer 1

Half width - 3.75 m

Rainfall intensity - 90 mm/hr

Longitudinal slope - 0.75%

Cross slope - 2.25%

Allowable limit of gutter flow, Q road = (Design constant x Intensity of rain x Area) / 360

= (0.91*90 * (9*L1*10∧-4) / 360 = 0.000204 L1

Using the standard design chart, allowable limit of gutter flow = 0.018 m3/s

Therefore, 0.018 = 0.000204 L1

L1 = 0.018 / 0.000204 = 88.24

Inlet spacing to be adapted is 88m