(b) Shipped in 26" long half sections, with a 24-inch effective length due to 2 inch overlap. (c) Bolted in every hole, threaded end alternated. (d) Cradled to prevent pipe shifting during back fill. (e) Place exhaust end, at the same grade as ditch, degrees off centerline. (f) Multiple must all be the same diameter. (g) Multiple pipe spacing is ½ the diameter of the pipe. (ON SLIDE #83) (3) Concrete Pipe Culverts: When available, concrete-pipe culverts should be used instead of CMP. Concrete has two advantages; first it is stronger and requires less cover than CMP to support the same load. Second, the interior surface of a concrete pipe is smoother than CMP allowing for smoother flow of water and less problems with debris restricting the flow of water. Because of these advantages, concrete pipe of the same diameter will carry a higher flow of water. The concern is once the water exits the pipe at a higher velocity, good erosion control methods must be in place to reduce erosion along the ditch past the pipe’s exit. Here are some general rules of thumb for the concrete pipe: (a) Can be constructed in any length or size. (b) Requires a concrete sealant when adjoining two sections or more of pipe together. (c) Substantial headwalls and exhaust are required to diminish the potential for separation at the joint ends. (d) Transportability will be slightly more difficult do to the weight of the concrete. (ON SLIDE #84, 85) Maximum Allowable Culvert Diameter. b. Permanent culverts are selected based on their diameter. There are two equations for determining the maximum diameter (Dmax) of a culvert. Both
(b) Shipped in 26" long half sections, with a 24-inch effective length due to 2 inch overlap. (c) Bolted in every hole, threaded end alternated. (d) Cradled to prevent pipe shifting during back fill. (e) Place exhaust end, at the same grade as ditch, degrees off centerline. (f) Multiple must all be the same diameter. (g) Multiple pipe spacing is ½ the diameter of the pipe. (ON SLIDE #83) (3) Concrete Pipe Culverts: When available, concrete-pipe culverts should be used instead of CMP. Concrete has two advantages; first it is stronger and requires less cover than CMP to support the same load. Second, the interior surface of a concrete pipe is smoother than CMP allowing for smoother flow of water and less problems with debris restricting the flow of water. Because of these advantages, concrete pipe of the same diameter will carry a higher flow of water. The concern is once the water exits the pipe at a higher velocity, good erosion control methods must be in place to reduce erosion along the ditch past the pipe’s exit. Here are some general rules of thumb for the concrete pipe: (a) Can be constructed in any length or size. (b) Requires a concrete sealant when adjoining two sections or more of pipe together. (c) Substantial headwalls and exhaust are required to diminish the potential for separation at the joint ends. (d) Transportability will be slightly more difficult do to the weight of the concrete. (ON SLIDE #84, 85) b. Maximum Allowable Culvert Diameter. Permanent culverts are selected based on their diameter. There are two equations for determining the maximum diameter (Dmax) of a culvert. Both
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