Hydraulic Efficiency of Grate and Curb Inlets - Urban Drainage and ...

Headbox
Pipe
Network
Inlets
Street
Section
Pumps
Flume
Section
Tailbox
Sharpcrested
Weirs
Sump
Inlet
Figure 3-1: Photograph of model layout
Contained within the flume section were the model’s road surface and all curb and inlet
components. Sufficient laboratory space allowed for construction of a two-lane street surface. A
cross section of the flume including the street section, gutter panel, and sidewalk is presented in
Figure 3-2. The street section was constructed as a 2-by-4 in. tubular steel framework and
decked with 1/8-in. thick sheet steel. Slope adjustment was achieved by the use of eight scissor
jacks placed under the street section, and adjustment ranged from 0.5% to 4% longitudinally and
from 1% to 2% laterally. Upstream of the street section, an approach section was constructed to
allow flow to stabilize after exiting the headbox. A diffuser screen was installed at the junction
between the headbox and the approach section to minimize turbulence and to distribute flow
evenly across the width of the model. The long horizontal approach section provided stabilized
flow. Prototype dimensions and characteristics are presented in Table 3-1, which can be directly
compared to Table 2-1 for the FHWA model. The physical model used provided a broader range
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