Hydraulics of Multibarrel Culverts Under Inlet Control
Journal of Irrigation and Drainage Engineering
The hydraulic characteristics of multi- and single-barrel circular culverts were compared in this study. One-, two-, and three-barrel culverts configurations, operating under inlet control, were tested in the laboratory with various approach conditions and barrel spacing (horizontal and vertical). The single-barrel head-discharge relationship was consistent with the average head-discharge relationship of the individual barrels in a multibarrel culvert configuration with a uniform upstream approach flow and uniform invert elevations. For the nonuniform approach flow condition, the single-barrel model overpredicted the average-barrel flow by up to 10%. With the middle barrel installed at a lower elevation than the outside barrels, in submerged flow the single-barrel head discharge relationship was consistent with the outside barrels, but the middle barrel was up to 7% more efficient than the single-barrel discharge. The flow rate variations are attributed, in part, to a reduction in approach flow contraction entering the center culvert in the three-culvert configuration and a nonuniform distribution of intermittently forming surface vortices at the culvert inlets. The results of a state (United States) Department of Transportation survey regarding multiple culvert use are also presented.
Haderlie, G. and B. Tullis (2008). “Hydraulics of Multibarrel Culverts Under Inlet Control.” J. Irrig. Drain. Eng., 134(4), 507-514.