Hydraulic Tests on Concrete Culvert Pipes

Abstract

Included in an experimental program conducted at the St. Anthony Falls Hydraulic Laboratory of the University of Minnesota on full-scale culverts was a series of tests on concrete pipes up to 3 ft in diameter. The primary purpose of these tests was to obtain pipe friction and entrance loss coefficients which would be more accurate and dependable than those currently recommended in culvert design literature. the studies were begun in 1946. This paper is confined to a discussion of the concrete culvert test program and the results of the studies.

The test series included three concrete culvert pipes, 18 inches, 24 inches, and 36 inches in diameter, respectively. Each pipe was 193 ft long and laid on a slope of 0.20 per cent, except that the 24-in. pipe was on a slope of 0.224 per cent. the pipes tested were all manufactured by the cast-and-vibrated process. Details of the pipe sections are shown on page 22.

Friction and entrance loss coefficients were established for the culverts under the usual conditions of field operations: (a) Full flow with submerged inlet and outlet. (b) Part-full flow at uniform depth.

The 18-in. and 36-in. diameter pipes were tested for each of the two types of flow with two different entrance conditions; namely, (a) pipe projecting 2 ft into the headwater pool, (b) pipe entrance flush with the headwall. The 24-in. pipe was tested with the projecting entrance only.