Page 67 - การระบายน้ำ

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ตารางที่ 5.6 Capacity and critical slope of culverts*

(Manning’s n of 0.012, 0.018, and 0.024)

Manning’s = 0.012 concrete pipe excellent condition of
surfacing alignment

Manning’s = 0.018 Corrugated metal pipe (CMP) invert

paved to 50% of diameter

Manning’s = 0.024 Corrugated metal pipe (CMP)
standard unpaved

Culverts with free outlet with water surface at inlet same elevation as top of pipe and outlet unsubmerged