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Publication Number: FHWA-RD-06-138
Date: October 2006

Effects of Inlet Geometry on Hydraulic Performance of Box Culverts

APPENDIX A. EXPANDED TEST MATRIX

This appendix is an expanded description of the test matrix. The expanded matrix includes sketches, more detailed information about test conditions, and extra tests that were conducted in response to questions posed during the study. The matrix was posted in the lab and used as a checklist during the experimental phase.

Figure 30 in chapter 5 contains the seven different bevel edge configurations that were tested in the miniflume to determine the best edge configuration. The criterion to determine the best edge configuration was the contracted distance outside the viscous boundary layer (effective flow depth at the vena contracta, also illustrated in figure 30). PIV data were used to analyze the flow at the culvert entrance and to quantify the effective flow depth.

Tables 13 through 16 summarize tests performed in the culvert test facility to analyze the effects of bevels, multiple barrels, span–to–rise ratios, and skewed headwalls. Two extra inlet geometries—an FC–S–0 hybrid and a PC–A hybrid—were tested in response to questions on the draft final report regarding the wingwall bevels and are included in table 16. The FC–S–0 hybrid was a combination of the field cast top bevel with the precast wingwall bevels, and the PC–A hybrid was a combination of the precast top bevel with the field cast square edge wingwalls.

Table 13. Tests to analyze the effects of bevels for wingwalls and top edges.
InletModel IDSketchWingwall flare angleBevelsCorner fillets (inches)Barrel size (feet)Culvert slopesTailwater
1.1FC–S–0View Alternate Text4–inch–straight top bevel, no WW bevel06 × 60.03, 0.007High,Low
1.2FC–S–0View Alternate Text4–inch–straight top bevel, no WW bevel66 × 60.03, 0.007High,Low
1.3FC–S–0View Alternate Text4–inch–straight top bevel, no WW bevel126 × 60.03, 0.007High,Low
1.4PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels06 × 60.03, 0.007High,Low
1.5PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels66 × 60.03, 0.007High,Low
1.6PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels126 × 60.03, 0.007High,Low
1.7PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels66 × 120.03High,Low
1.8PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels126 × 120.03High,Low
1.9FC–S–0 HybridView Alternate Text4–inch–straight top bevel, 4–inch–radius WW bevels06 × 60.03High,Low
1.10PC–A HybridView Alternate Text8–inch–radius top bevel, no WW bevels06 × 60.03High,Low
1 inch = 2.54 cm; 1 ft = 0.305 m
Notes: Target discharge intensities for unsubmerged flow, Q⁄AD0.5 = 0.5, 1.0, 2.0, 3.5, and 4.0 (ft0.5⁄s). Target discharge intensities for submerged flow, Q⁄AD0.5 = 4.5, 5.0, 5.5, and 6.0 (ft0.5⁄s). One ft0.5⁄s equals 0.552 m0.5⁄s. Contraction ratio of headbox width to total span of culvert model was held constant at 2.67. WW is wingwalls.
Table 14. Tests to analyze the effects of multiple barrels.
InletModel IDSketchWW flare angleBevelsBarrel size (feet)Culvert slopesCorner fillets (inches)BarrelsInner Wall
2.1FC–S–0View Alternate Text4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00761None
2.2FC–S–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00761None
2.3FC–D–0View Alternate Text4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00762Not extended
2.4FC–D–0–EView Alternate Text4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00762Extended
2.5FC–D–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00762 Not extended
2.6FC–D–30–EView Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00762Extended
2.7FC–T–0View Alternate Text4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00763Not extended
2.8 FC–T–0–EView Alternate Text4–inch–straight top bevel, no WW bevel6 × 60.03, 0.007 63Extended
2.9 FC–T–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 60.03, 0.007 63Not Extended
2.10FC–T–30–EView Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00763Extended
2.11FC–Q–0View Alternate Text4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00764 Not extended
2.12FC–Q–0–EView Alternate Text4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00764Extended
2.13FC–Q–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00764Not extended
2.14FC–Q–30–EView Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00764Extended
2.15PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 60.03, 0.007121None
2.16PC–BView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 60.03, 0.007122Not extended
2.17PC–B–EView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 60.03, 0.007122Extended
2.18PC–CView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 60.03, 0.007123Not extended
2.19PC–C–EView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 60.03, 0.007123Extended
2.20PC–DView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 60.03, 0.007124Not extended
2.21PC–D–EView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 60.03, 0.007124Extended
1 inch = 2.54 cm; 1 ft = 0.305 m
Notes: Target discharge intensities for unsubmerged flow, Q⁄AD0.5 = 0.5, 1.0, 2.0, 3.5, and 4.0 (ft0.5⁄s). Target discharge intensities for submerged flow, Q⁄AD0.5 = 4.5, 5.0, 5.5, and 6.0 (ft0.5⁄s). One ft0.5⁄s equals 0.552 m0.5⁄s. Contraction ratio of headbox width to total span of culvert model was held constant at 2.67. WW is wingwalls.
Table 15. Tests to analyze the effects of the span–to–rise ratio.
InletModel IDSketchWW flare angleBevelsBarrel size (feet)Culvert SlopesCorner fillets (inches)Span–to–rise
3.1FC–S–0View Alternate Text4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00701:1
3.2FC–S–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 60.03, 0.00701:1
3.3PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 60.03, 0.00701:1
3.4FC–S–0View Alternate Text4–inch–straight top bevel, no WW bevel6 × 12 0.03, 0.00702:1
3.5FC–S–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 120.03, 0.00702:1
3.6PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 120.03, 0.00702:1
3.7FC–S–0View Alternate Text4–inch–straight top bevel, no WW bevel6 × 180.03, 0.00703:1
3.8FC–S–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 180.03, 0.00703:1
3.9PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 180.03, 0.00703:1
3.10FC–S–0View Alternate Text4–inch–straight top bevel, no WW bevel6 × 240.03, 0.00704:1
3.11FC–S–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 240.03, 0.00704:1
3.12PC–AView Alternate Text8–inch–radius top bevel, 4–inch–radius WW bevels6 × 240.03, 0.00704:1
1 inch = 2.54 cm; 1 ft = 0.305 m
Notes: Target discharge intensities for unsubmerged flow, Q⁄AD0.5 = 0.5, 1.0, 2.0, 3.5, and 4.0 (ft0.5⁄s). Target discharge intensities for submerged flow, Q⁄AD0.5 = 4.5, 5.0, 5.5, and 6.0 (ft0.5⁄s). One ft0.5⁄s equals 0.552 m0.5⁄s. Contraction ratio of headbox width to total span of culvert model was held constant at 2.67. WW is wingwalls.
Table 16. Tests to analyze the effects of skew.
InletModel IDSketchWW flare angleBevelsBarrel size (feet)Culvert slopesCorner fillets (inches)BarrelsSpan–to–riseSkew
4.1FC–T–0View Alternate Text4–inch–straight top bevel, no WW bevel6 × 60.03,0.00703
4.2FC–T–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 60.03,0.00703
4.3 FC–T–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 6 0.03,0.007 0 3 15°
4.4 FC–T–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 6 0.03,0.007 0 3 30°
4.5 FC–T–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 6 0.03,0.0070345°
4.6 FC–S–30View Alternate Text30°4–inch–straight top bevel, no WW bevel6 × 18 0.03,0.00703:130°
1 inch = 2.54 cm; 1 ft = 0.305 m
Notes: Target discharge intensities for unsubmerged flow, Q⁄AD0.5 = 0.5, 1.0, 2.0, 3.5, and 4.0 (ft0.5⁄s). Target discharge intensities for submerged flow, Q⁄AD0.5 = 4.5, 5.0, 5.5, and 6.0 (ft0.5⁄s). One ft0.5⁄s equals 0.552 m0.5⁄s. Contraction ratio of headbox width to total span of culvert model was held constant at 2.67. WW is wingwalls.

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The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT).
The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT). The hydraulics and hydrology research program at the TFHRC Federal Highway Administration's (FHWA) R&T Web site portal, which provides access to or information about the Agency’s R&T program, projects, partnerships, publications, and results.
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