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Recommended Minimum Angle between adjacent pipe centerlines in round (Alt. A) structure bottoms

  • Reference Table 6.4-6 from the FDOT Drainage Design Guide [handbook].
  • Numbers to the right of the degree values are the structure bottom inside diameters.
  • Values are based on a 2" (minimum) precast section along the inside structure wall between adjacent pipes, and precast openings for concrete pipe.
  • Reference Index 200 (Sheet 3 of 5) from the FDOT Design Standards.
  • PCSA and FDOT have proposed precast openings of O.D. plus 6".

Outside Pipe Diameter + 6"

Pipe
Size
Adjacent Pipe Size
18" 24" 30" 36" 42" 48" 54" 60" 66"
18" 45° 7' 49° 7' 54° 7' 59° 7' 69° 7' 75° 7' 83° 7' 92° 7' 114° 7'
52° 6' 58° 6' 63° 6' 70° 6' 84° 6' 94° 6'
64° 5' 71° 5' 78° 5' 87° 5'
82° 4' 90° 4' 105° 4'
24" 53° 7' 58° 7' 63° 7' 74° 7' 80° 7' 87° 7' 96° 7' 118° 7'
63° 6' 69° 6' 75° 6' 90° 6' 100° 6'
78° 5' 85° 5' 94° 5'
102° 4' 114° 4'
30" 63° 7' 68° 7' 78° 7' 85° 7' 92° 7' 101° 7' 123° 7'
75° 6' 81° 6' 95° 6' 105° 6'
93° 5' 101° 5'
127° 4'
36" 72° 7' 83° 7' 89° 7' 97° 7' 106° 7' 128° 7'
91° 6' 101° 6' 111° 6'
110° 5'
42" 90° 7' 100° 7' 107° 7' 117° 7' 138° 7'
116° 6' 126° 6'
48" 106° 7' 114° 7' 123° 7' 145° 7'
136° 6'
54" 121° 7' 130° 7' 152° 7'
60" 139° 7' 161° 7'
Pipe
Size
18" 24" 30" 36" 42" 48" 54" 60" 66"