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HY-8 User Manual (v7.3)

1. Ratio of roughness element height divided by the diameter of the culvert opening at the roughness element Range 005 to 1 L P Ratio of the roughness length to inside perimeter Range 0 0 to 1 0 Diameter of roughened section Opening D The following figure shows the flow regimes and variables for an increased resistance energy dissipator implemented in a circular culvert C Le j ki u a Quasi smooth Flow b Hyperturbulent c Isolated Flow Roughness Flow Variables from the figure L Length from beginning of one roughness element to the beginning of the next roughness element h height of roughness element D diameter of roughened section opening Tumbling Flow in Box Culverts 91 Tumbling Flow in Box Culverts The input variables required for this calculation is the following Roughness Spacing to Height Ratio The user must select a value of either 8 5 or 10 for the ratio of roughness element spacing divided by roughness element height If after calculations the flow through the roughened section of the culvert impacts on the culvert roof then the minimum enlarged section height needed to correct this problem will be given and the user will be prompted to enter a value equal to or larger than this minimum value Height which must be equal to or greater than the height of the culvert The following figures show two configurations of tu
2. 2 Building a Project Building a Project Building a Project An HY 8 project involves the design and analysis of single or multiple culverts at one or more crossings The process of building a culvert project involves the following steps Locate Project Culvert Crossing Data Run Analysis Report Generation Crossings may be added to the project as needed Locate Project Locate Crossing The first step in building a project is to identify the location of the crossing The project contains all of the crossings while the crossings are the locations at which the culverts are placed If desired not required the map viewer tool may be used to locate the crossing by entering latitude longitude coordinates or the address of the crossing as shown in the figure below Virtual Earth Map Locator Map Style Map Options Jump Map Location Map Controls Road 46 0 bea v Show labels Uinta National Forest Springville Mapieton Spanish Fork 10 miles 749 D 2006 Microsoft Corporation 2006 NAVTEQ AND Harris Corp Earttstar Geographics LLC Culvert Crossing Data 11 Culvert Crossing Data Input Crossing and Culvert data The user may choose up to 99 barrels for each culvert that is defined by the same site conditions shape configuration culvert type and n and or up to 6 independent culverts In both cases the culverts share the same headwater pool tailwa
3. Polynomial Coefficients 61 Table 8 User Defined Open Bottom Arch Low Profile Arch High Profile Arch and Metal Box HW D Values Q A D 5 05 1 2 3 4 5 6 7 8 9 HY 8 Interpolation Coefficients Inlet Configuration KE SR 1 AQ A 3 A 4 5 A 6 ACD A 8 AQ 10 1 Thin Edge Projecting 0 9 0 5 0 31 0 48 0 81 1 11 1 42 1 84 2 9 3 03 3 71 4 26 2 Mitered to Conform to Slope 0 7 0 7 0 34 0 49 0 77 1 04 1 45 1 91 2 46 3 06 3 69 4 34 3 Square Edge with Headwall 0 5 0 5 0 31 0 46 0 73 0 96 1 26 1 59 2 01 2 51 3 08 3 64 4 Beveled Edge 0 2 0 5 0 31 0 44 0 69 0 89 1 16 1 49 1 81 2 23 2 68 3 18 Reference for User defined interpolation coefficients FHWA HDS 5 Appendix D Chart 52B References 1 http etd byu edu 2 http fhwicsintO1 fhwa dot gov publications research infrastructure hydraulics 06138 62 5 2 2 Outlet Control Outlet Control Computations Outlet Control Flow Types Outlet control means that the amount of water the culvert barrel can carry is limited by the barrel and or tailwater conditions downstream As a result the flow in the barrel is subcritical and the energy equation may be used to find the upstream headwater depth Several flow profiles are possible as are shown below and as described in HDS 5 HY 8 flow type
4. e 2 al z ii aum S z w gt s m e m e E 620 N us od z 2 E 560 N E M04 wr S z E450N 7 E 420 N 0 E30N 5 E350N d d 3 L 2 a E300N z n m 20 E20N a E 150 a Micron E100N W d Virtual Earth E ul AES Cornutus 8 8 After defining the culvert properties the analysis including overtopping of the roadway is completed and the performance output can be evaluated graphed and summarized in reports A sample of the first output screen is shown below E Summary of Flows at Crossing Kiwanis 109 57 Display _ __ Geometry Plot mmary Table Inlet Elevation 100 50 ft Crossing Su Outlet Elevation 100 00 Ft Crossing Rating Curve Culvert Summary Table aasan i Culvert Length 60 00 ft Water Surface Profiles Culvert Performance Curve Culvert Slope 0 0083 Improved Inlet Table Inlet Crest 0 00 ft C Selected Water Profile Customized Table Options Inlet Throat 0 00 ft Help Flow Types Outlet Control Profiles This is the general work flow of a HY 8 project The rest of this help file document provides more detailed information about data input analysis and reporting Differences from DOS HY 8 Differences from DOS HY 8 Differences Between DOS 8 and 8 7 0 An important objective of the conversion of the HY 8 program to a Windows
5. 0 0447052 0 00343602 8 96610E 05 2 Mitered to Conform to Slope 0 7 0 7 0 107137 0 757789 0 361462 0 1233932 0 01606422 0 00076739 3 Square Edge with Headwall 0 5 10 5 10 167433 0 538595 0 149374 0 0391543 0 00343974 0 000115882 Steel Aluminum Corrugated PE 4 Grooved End Projecting 0 2 0 5 0 108786 0 662381 0 233801 0 0579585 0 0055789 0 000205052 5 Grooved End in Headwall 0 2 0 5 0 114099 0 653562 0 233615 0 0597723 0 00616338 0 000242832 6 Beveled Edge 1 1 0 2 0 5 0 063343 0 766512 0 316097 0 0876701 0 009836951 0 00041676 7 Beveled Edge 1 5 1 0 2 0 5 0 08173 0 698353 0 253683 0 065125 0 0071975 0 0003 12451 8 Sq proj 0 2 0 5 0 167287 0 558766 0 159813 0 0420069 0 00369252 0 000125169 9 Square Edge with Headwall 0 5 0 5 0 087483 0 706578 0 253295 0 0667001 0 00661651 0 000250619 Concrete PVC HDPE Polynomial Coefficients 55 10 end sect 0 4 0 5 0 120659 0 630768 0 218423 0 0591815 0 00599169 0 000229287 EQ s REFERENCE 1 9 Calculator Design Series CDS 3 for TI 59 FHWA 1980 page 60 1 10 Hydraulic Computer Program HY 1 FHWA 1969 page 18 Table 2 Polynomial Coefficients Embedded Circular HY 8 Equation Inlet Configuration KE SR A BS DIP
6. 0 0557401882 0 4998819105 0 1249164198 0 0219465031 0 0015177347 0 0000404218 Mitered to Conform to Slope amp 1 coefficients are used if the span rise ratio is greater than 3 1 4 1 45 Degrees 0 5 0 0 0 0465032346 0 5446293346 0 1571341119 0 0312822438 0 0024007467 0 000070401 1 E 45 degree B Wingwall amp 1 coefficients are used if the span rise ratio is greater than 3 1 4 1 90 Degrees 0 5 0 0 0 0401619369 0 5774418238 0 1693724912 0 0328323405 0 0024131276 0 0000668323 Square Edge uil with Headwall essen Eis amp 1 coefficients are used if the span rise ratio is greater than 3 1 References for Concrete Open bottom Arch polynomial coefficients Thiele Elizabeth A Culvert Hydraulics Comparison of Current Computer Models pp 121 126 Brigham Young University Master s Thesis 2007 Chase Don Hydraulic Characteristics of CON SPAN Bridge Systems Submitted Study and Report 1999 Polynomial Coefficients 59 Table 7 Polynomial Coefficients South Dakota Concrete Box Description KE SR A BS C DIP EE F Diagram Notes Sketch 1 30 degree flared wingwalls top edge beveled at 45 degrees 0 5 0 5 0 0176998563 0 5354484847 0 1197176702 0 0175902318 0 0005722076 0 0000080574 A Z Sketch 2 30 degree flared wingwalls top edge beveled at 45 d
7. 110 000 105 000 98 000 105 000 110 000 Figure 1 Irregular Channel Tailwater Editor Manning s n is defined as shown in the figure below n value is assigned for each segment of the cross section beginning at the left looking downstream coordinate below If the n value is the same throughout the cross section the user may copy the value be dragging the value from the first cell Irregular Channel 25 Tailwater Cross Section gt eo 106 c 9 S 104 102 100 98 0 20 40 60 80 100 120 Station ft Irregular Channel Error When the capacity of an irregular channel is not sufficient to convey the range of discharges version 6 1 of HY 8 spilled excess water into an infinitely wide floodplain see drawing below The rating curve shows a constant tailwater elevation cross section velocity and computed shear stress for all discharges exceeding the channel capacity In HY 8 the spill concept is not used If the irregular cross section cannot convey the range of discharges entered by the user the following error message is displayed Irregular tailwater channel is not big enough to convey flow The user has two options to correct this error The first option is to enter additional data points for the purpose of extending the cross section horizontally and vertically based on field surveys or best judgment This option could be used to simulate the spill
8. Units Culvert Shape Box Froude Number 1 3 4229 Depth 1 0 7778 ft Length of Jump 18 77 ft Station 1 46 0 ft Station 2 64 8 ft Hydraulic Jump Calculations 75 Culvert Combined Profiles Figure 5 Water Profile with Hydraulic Jump with Calculated Jump Length When HY 8 finishes computing the hydraulic jump length and has applied it to the profile HY 8 trims the profile to stay within the culvert barrel The completed profile is shown in Figure 6 Culvert Completed Profile Figure 6 Completed Water Surface Profile Hydraulic Jump Calculations 76 References Lowe N J 2008 THEORETICAL DETERMINATION OF SUBCRITICAL SEQUENT DEPTHS FOR COMPLETE AND INCOMPLETE HYDRAULIC JUMPS IN CLOSED CONDUITS OF ANY SHAPE Provo Utah Brigham Young University Bradley J N and Peterka A J The hydraulic design of stilling basins hydraulic jumps on a horizontal apron Basin I Journal of the Hydraulics Division ASCE 83 HY5 1401 1 24 1957 Hager W H Energy Dissipators and Hydraulic Jump Kluwer Academic Publishers Dordrecht Netherlands 1992 References 1 http contentdm lib byu edu u ETD 1623 77 5 3 Tables and Plots Tables and Plots After analyzing the culvert crossing the user can view the following tables and plots Crossing Summary Table Culvert Summary
9. nlet Control Depth Inlet control headwater depth above inlet invert Outlet Control Depth Outlet control headwater depth above inlet invert Flow Type USGS flow type Full Flow HDS 5 is shown if full flow outlet control option is selected Crest Control Elevation Headwater elevation calculated assuming crest control Face Control Elevation Headwater elevation calculated assuming face control Throat Control Elevation Headwater elevation calculated assuming throat control Tailwater Elevation Tailwater elevation at culvert outlet from downstream channel The tapered inlet table also provides the option of plotting and viewing the culvert performance curve Customized 81 Customized The customized table is set up by the user by clicking on the options button when the customized table feature is selected The figure below shows the different variables that can be displayed in the culvert summary profile and tapered inlet tables 7 Total Discharge V Culvert Discharge 4 Headwater Elevation V Inlet Control Depth V Outlet Control Depth V Flow Type Normal Depth Critical Depth Outlet Depth Tailwater Depth Outlet Velocity Tailwater Velocity PROFILE TABLE E Length Full E Length Free TAPERED INLET TABLE Crest Control Elevation Face Control Elevation Throat Control Elevation Tailwater Elevation Controlling Plot Display Options 82 Controlling Plot Display Options
10. than culverts with a 2 1 span to rise ratio Because of this separate polynomial coefficients were determined for culverts with each of these span to rise ratios Dr Chase s study determined the K c M and Y NBS coefficients described in HDS 5 and these coefficients were fitted to a 5th degree polynomial equation so they can be used in HY 8 In HY 8 the 2 1 coefficients are used if the span rise ratio is less than or equal to 3 1 and the 4 1 coefficients are used if the span rise ratio is greater than 3 1 If the culvert you are modeling has less than a 2 1 or greater than a 4 1 span to rise ratio you will see a note in HY 8 saying that your culvert is outside of the tested span to rise ratios Concrete Open Bottom Arch 32 Further testing may be required to account for these large or smaller span to rise ratios but it is likely that your computed headwater will be higher than the observed headwater if your span rise ratio is greater than 4 1 and your computed headwater will be less than that observed if the span rise ratio is less than 2 1 For information on the exact coefficients used and to view diagrams showing the different culvert wingwall configurations see the help describing the HY 8 polynomial coefficients References 1 http hy8 aquaveo com ConspanCoordinates pdf South Dakota Concrete Box HY 8 Version 7 3 and later has coefficients for computing inlet control depths using research contained in FHWA
11. EE 1 20 Embedded Projecting End Pond 1 0 0 0608834861787302 0 485734308768152 0 138194248908661 0 027539172439404 0 00214546773150856 0 0000642768838741702 4096 Embedded Projecting End Pond 1 0 0 0888877561313819 0 431529135749154 0 073866511532321 0 0159200223783949 0 00103390288198853 0 0000262133369282047 5096 Embedded Projecting End Pond 1 0 0 0472950768985916 0 59879374328307 0 191731763062064 0 0480749069653899 0 00424418228907681 0 00014115316932528 2096 Embedded Square Headwall 0 55 0 5 0 0899367985347424 0 363046722229086 0 0683746513605387 0 0109593856642167 0 000706535544154146 0 0000189546410047092 4096 Embedded Square Headwall 0 55 0 5 0 074298531535586 0 4273662972292 0 0849120530113796 0 0157965200237501 0 0010265 1687866388 0 0000260155937601425 5096 Embedded Square Headwall 0 55 0 5 0 212469378699735 0 511461899639209 0 174199884499934 0 0410961018431149 0 00366309685788592 0 00012308539522765 1 20 Embedded 45 degree Beveled End 0 35 0 5 0 0795781442396077 0 3733 19755852658 0 082 1508852481996 0 0148670702428601 0 00121876746632593 0 00004068961 11847521 40 Embedded 45 degree Beveled End 0 35 0 5 0 0845740029462746 0 389113662011417 0 068509065498
12. The second report type is Summary which includes the crossing and culvert summary tables along with the site tailwater roadway and culvert data Custom is the final report type in which the user designates which topics to include in the report Report Content This section is divided into available fields and included fields The available fields section comprises a list of all possible report topics the user can include in the report Topics found in the included fields section are what will be displayed in the final report These fields will appear in the report in the same order they appear here but they may be moved up or down in the list by selecting the desired topic and clicking on the button describing the direction the user wants the topic to move To add or remove topics the user selects the appropriate topic and clicks the right or left arrow button depending on the desired result Report Generation 15 Report Generator m Choose crossing s to include BOX Format Report Type standard Report File Format File name RTF HY8Report Formatting Options eal Report Content Choose fields to include Available Fields Project Motes Project Plan View Image Project Units Project Outlet Control Option Crossing Summary Table Crossing Rating Curve Plot Culvert Summary Tables Culvert Performance Curve Water Surface Profile Table Water Surface Profile Plot Improved
13. a Use HY8 Equation Number 2 b HDS5 Chart Number 2 2 Plastic Pipe Materials 30 c Equation for Corrugated Metal pipe culvert Mitered to conform to slope 2 Smooth HDPE a Manning s n From HDS 5 0 009 0 015 use 0 012 b Inlet Configurations 1 Square Edge with Headwall 1 Notes a Use HY8 Equation Number 9 b HDS5 Chart Number 1 1 c Equation for Concrete Pipe Square Edge with Headwall ii Beveled Edge 1 1 1 Notes a Use HY8 Equation Number 6 b HDS5 Chart Number 3 A c Equation for Circular pipe culvert with beveled edge 1 1 iii Beveled Edge 1 5 1 1 Notes a Use HY8 Equation Number 7 b HDS5 Chart Number 3 B c Equation for Circular pipe culvert with beveled edge 1 5 1 iv Thin Edge Projecting 1 Notes a Use HY8 Equation Number 1 b HDS5 Chart Number 2 3 c Equation for Corrugated Metal pipe culvert Thin edge projecting v Mitered to Conform to Slope 1 Notes a Use HY8 Equation Number 2 b HDS5 Chart Number 2 2 c Equation for Corrugated Metal pipe culvert Mitered to conform to slope 3 Corrugated PE a Manning s n From HDS 5 0 009 0 015 use 0 024 b Inlet Configurations i Square Edge with Headwall 1 Notes a Use HY8 Equation Number 3 b HDS5 Chart Number 2 1 c Equation for Corrugated Metal pipe culvert with Headwall ii Beveled Edge 1 1 1 Notes Plastic Pipe Materials 3l a Use HY8 Equation Number 6 b HDS5 Chart Number 3 A c Equation for Circular pipe culvert wi
14. dco Compute normal depth dno Compute fullflow if nomograph solution assumed 6 FFt or FFc If dno gt 95 rise assume fullflow 6 FFn If dno dco assume mild slope SEE OUTLET DAT If dno lt dco assume steep slope A If twh is gt So L rise assume fullflow 4 FFt ON B If twh is gt rise outlet submerged assume inlet unsubmerged C If twh is rise outlet is unsubmerged assume inlet unsubmerged i Assume headwater oh inlet control headwater ih Calculate S2 curve 1 S2n for outlet depth If oh gt rise inlet submerged 5 S2n ii If twh gt headwater tailwater drowns out jump Calculate curve 3 MIt If culvert flows part full 7 Mit FLOW SUBMERGED CONTROL rer T OUTLET 1 inet No No None GS2n Normal Na S2n Template loop detected WMS HY 8 Flow Types Exit Loss Options 67 Exit Loss Options Introduction HY 8 version 7 1 incorporates an alternative modified equation for defining culvert exit loss The method described in HDS 5 uses the energy equation and several assumptions to compute the exit loss for a culvert The equation that is given in HDS 5 ignores the velocity head downstream from a culvert barrel and is given as the following Ho 29 where ko 1 0 Where H is the exit loss V is the velocity inside the culvert barrel and g is gravity However exit losses obtained from this expressi
15. 23 0 22 0 22 0 20 0 31 6 0 38 0 36 0 34 0 36 0 34 0 32 0 34 0 32 0 30 0 30 0 28 0 48 12 0 45 0 42 0 25 0 40 0 38 0 36 0 36 0 34 0 32 0 30 0 28 0 37 12 0 52 0 50 0 18 0 48 0 46 0 44 0 44 0 42 0 40 0 38 0 36 Riprap Basin and Apron 108 Riprap Basin and Apron Riprap Basin and Apron The input variables required for this calculation is the following Condition to compute Basin Outlet Velocity The user can select Best Fit Curve or Envelope Curve The user should choose Best Fit Curve if the flow downstream of the basin is believed to be supercritical If the flow downstream is believed to be subcritical the user should choose Envelope Curve D50 of the Riprap Mixture Mean diameter by weight of the riprap to be used DMax of the Riprap Mixture Maximum diameter by weight of the riprap to be used The design criteria for this basin was based on model runs in which D50 YE ranged from 0 1 to 0 7 values outside this range are rejected by the program The following figures show riprap basins and aprons DISSIPATOR POOL APRON CHANNEL 10hs or 3Wo 5hs or Wo TOP OF RIPRAP 7 Variables from the figure hy Dissipator pool depth Wo Culvert width TW Tailwater depth E rem Equivalent brink outlet depth Median rock size by weight 50 d Max rock size
16. Depth at the culvert outlet Approach depth at two culvert widths downstream of the culvert outlet s Depth at exit W Culvert width at the culvert outlet 0 L Total basin length Colorado State University CSU Rigid Boundary Basin 107 e L Longitudinal spacing between rows of elements Wp Ws 4 Wap Wy 5 Wp Wo 6 Wal Wo 7 Eu L PSY a Wpg Wo 8 6 E 21 28 5 5 5 4 4 L 4 3 L 3 fe 2 L 2 gt 2 1 L 1 1 2Wo Nr i i Nr Ei lw Wo Variables from the a W Width of basin W Culvert width at the culvert outlet e L Longitudinal spacing between rows of elements N Row number W Wo 2 to 4 5 6 8 w w 0 57 0 63 0 6 0 58 62 Rows N 4 3 6 4 5 6 4 5 6 5 6 6 Elements N 14 17 21 15 19 23 17 22 27 24 30 30 Rectangular h y x L h Basin Drag Coefficient C 91 6 10 32 0 28 0 24 0 32 0 28 0 24 0 31 0 27 0 23 0 26 0 22 0 22 71 6 0 44 0 40 0 37 0 42 0 38 0 35 0 40 0 36 0 33 0 34 0 31 0 29 0 48 12 0 60 0 55 0 51 0 56 0 51 0 47 0 53 0 48 0 43 0 46 0 39 0 35 0 37 12 0 68 0 66 0 65 0 65 0 62 0 60 0 62 0 58 0 55 0 54 0 50 0 45 Circular 0 91 6 0 21 0 20 0 48 0 21 0 19 0 17 0 21 0 19 0 17 0 18 0 16 0 71 6 0 29 0 27 0 40 0 27 0 25 0 23 0 25 0
17. HF2 THEN HF1 FACE CONTROL FOR SLOPE TAPERED INLET 1 ZZ Q BF SQR RISE 3 2 Calculate UNSUBMERGED 1 5 RISE ZZ 66667 A For bevels 0378 ZZ ZZ 7 RISE IF 1 gt RISE THEN HF IF HFI lt RISE THEN HF 1 IF HFI gt THEN HF 1 B For other edges HF2 0446 ZZ ZZ 64 RISE IF gt RISE THEN HF HF2 IF HFI lt RISE THEN HF 1 IF HFI gt HF2 THEN HF 1 CREST CONTROL 1 HC 2 5 Q CW 66667 OUTLET CONTROL PROCEDURES THAT PRODUCE AN INLET CONTROL PROFILE STEP Compute critical depth dco Compute normal depth dno Compute fullflow if nomograph solution assumed 6 FFt or FFc If dno gt 95 rise assume fullflow 6 FFn If dno dco assume mild slope SEE OUTLET DAT If dno lt dco assume steep slope A If twh is gt So L rise assume fullflow 4 FFt Inlet Control Computations 53 B If twh is gt rise outlet submerged assume inlet unsubmerged C If twh is rise outlet is unsubmerged assume inlet unsubmerged 1 Assume headwater oh inlet control headwater ih Calculate S2 curve 1 S2n for outlet depth If oh gt rise inlet submerged 5 S2n ii If twh gt headwater tailwater drowns out jump Calculate curve 3 MIt If culvert flows part full 7 Mit FLOW CONTROL Template loop detected WMS HY 8 Flow Types Pol
18. REGRESSION EQUATIONS Q between Q at 5D and Q at 3D 1 CIRCULAR A See Straight inlet equations B SIDE TAPERED ELLIPTICAL TRANSITION THROAT CONTROL ZZ Q SQR RISE 5 Y LOG ZZ 2 30258 i IF n lt 015 THEN SMOOTH PIPE IMPROVRD INLET ii If n 22 015 then ROUGH PIPE IMPROVED INLET iii Calculate THROAT CONTROL iv Calculate FACE CONTROL v IF Depression Then CW CWF calculate CREST control C SIDE TAPERED RECTANGULAR TRANSITION or SLOPE TAPERED i Calculate THROAT CONTROL ii Calculate FACE CONTROL iii IF Depression Then CW CWF calculate CREST control 2 BOX CULVERTS A See Straight inlet equations B SIDE TAPERED RECTANGULAR TRANSITION or SLOPE TAPERED i Calculate THROAT CONTROL ii Calculate FACE CONTROL iii IF Depression Then CW CWF calculate CREST control 3 PIPE ARCHES AND ELLIPSES A See Straight inlet equations 4 IRREGULAR SHAPE Inlet Control Computations 48 A See Straight inlet equations Straight Inlet Equations 1 For IRREGULAR shape X Q AC SQR RISE IF X lt 5 THEN IH A 1 X 5 RISE ELSE IH AQ 1 AQ AG D X J 2 INO RISE 2 For all others shapes X Q SPAN SOR RISE 3 SR SR IC C D E F X X X X X SR SO RISE 3 Headwater elevation IHD IH if no Depression 4 For Depression CREST headwater is checked THROAT CONTROL TAPERED INLET 1 X Q SPAN SQR RISE 3 2
19. The available plots in HY 8 are managed by the user through right clicking in the plot window Because the same plot library is used for all plots culvert profiles front views performance curves etc they can all be controlled in the same fashion but the menus are slightly different depending on the plot For example the right click menu for the front and side views of the main HY 8 window include menus for editing the culvert crossing data analyzing the culvert crossing and defining culvert notes The right click menu for a performance curve would not include these menus However it should be emphasized that changing the display options of a plot window DOES NOT alter the hydraulic computations it only modifies the display of currently computed values Culvert Stations Crossing EX MIF Design Discharge 1000 0 cfs Culvert EX MIF Culvert Discharge 1000 0 cfs Culvert Crossing Data Analyze Crossing Culvert Notes Display Options Axis Titles 4 i M Set s Display Defaults Legend Se ees TELET Frame Plot Maximize Plot View values 2 E 4 4 Export Print I I 45000 45200 45400 45600 45800 46000 46200 46400 46500 Station ft The right click menu provides options for the user to control the Display Options of the plot These options include the
20. The various flow type properties may be found in HY 8 by selecting the Flow Types button from the Culvert Summary Table and are shown below Because the flow in the barrel is supercritical outlet losses and friction losses are not reflected in the headwater elevation The headwater elevation is a function of the entrance size shape and culvert type The computed inlet control headwater elevation is found by accessing the results of scaled physical model tests The logic for determining what inlet flow control type prevails is shown below from the original HY 8 help file UNSUBMERGED INLET SUBMERGED INLET r ee Flow Type 1 Flow Type 5 Inlet Control Computations 47 Inlet Control Logic DETERMINE APPLICABLE INLET CONTROL EQUATION 1 IF circle or box with IMPROVED INLETS then use INLET equations 2 For Straight previously called conventional INLETS A If Q is Q at 5D then assume LOW FLOW INLET CONTROL i calculate CRITICAL DEPTH DCO ii calculate Section Properties iii VH Q 2 64 4 iv IH DCO LMULT 1 KELOW VHCOEF IF no Depression THEN IH For Depression HF IH and check head on CREST B If Q Q at 5D but Q at 3D then use INLET REGRESSION EQUATIONS C If Q Q at 3D then assume HIGH FLOW INLET CONTROL i IH Q CDAHI 5 RISE ii IF no Depression THEN IHI IH For Depression HF IH and check head on CREST INLET
21. ability to modify fonts symbols colors axis ranges and titles legends exporting and more as shown in the Display Options dialog below Controlling Plot Display Options 83 Performance Curve Customization General Plot Axis Font Color Style Main Title Performance Curv si Sub Title Culvert EX MIF Border Style r Numeric Precision No Border C Line C0 3 Shadow C 3D Inset C 4 S LE Miewing Style r Grid Lines Color Both CY CX C None Monochrome Grid in front of data C Monochrome Symbols Font Size Large C Medium C Small OK ppli Help Export Maximize Some of the more commonly used options like axis titles legends and exporting are available directly from the right click menu Controlling Plot Display Options 84 Exporting and Printing The plot may be exported to three different locations the system clipboard a file or printer You can also export to the following formats MetaFile BMP JPG PNG Text The text format is a table of the values that are plotted These can be viewed by right clicking on the plot and selecting View Values If you are exporting a MetaFile BMP JPG or PNG You can select the size of the image you wish to export Exporting Crossing EX M1F Design Discharge 1000 0 cfs MetaFile C BMP JPG C PNG C Text 2 Data Only z Export Destinat
22. each section HY 8 determines starting conditions for each section of a broken back culvert so the direct step method can be computed The starting conditions HY 8 determines include the Broken Back Culverts 37 water depth at the beginning and end of each section the computation direction for each section and whether the water surface increases or decreases in depth in the downstream direction for each section The starting conditions for steep broken back culvert sections are initialized based on the flowchart below Once HY 8 computes a profile for one section it updates the water surface profile depth for the section s that it is next to HY 8 pieces the profiles for each section together to create a seamless water surface profile through the broken back culvert Broken Back Culverts 38 Broken Back Culvert Results When analyzing broken back culverts in HY 8 the normal and critical depth in the Culvert Summary Table is not shown because it can vary by section The flow type reported is the flow type of the upper section The option to display the Tapered inlet table is not available and instead there is a Broken Back Section option After selecting this option select Upper or Runout if it is a single broken back culvert or select Upper Steep or Runout This option displays a table that is similar to the Culvert Summary Table displaying the flow type normal depth and critical depth of the selected culvert
23. environment was maintaining the basic philosophy and simplicity model input and operation While we feel this has been largely achieved there were obviously some things that we wanted to change and add in order to take advantage of the more modern Windows operating system This page outlines these changes and new features and will serve as a road map to users who have longed used the DOS version of HY 8 Crossings Previous versions of HY 8 allowed for a single crossing to be designed Multiple culverts and barrels could be defined but in a given project only the culvert design information for a single roadway crossway could be defined and analyzed If in the context of a larger design project multiple crossings needed to be analyzed then each one was defined in a separate input file In HY 8 version 7 0 any number of crossings can be defined within the same project While it is just as simple to have a single crossing mimicking older versions of HY 8 you also have the option of performing an analysis on several crossings and grouping them together The new mapping feature described below helps you to create a map identifying each crossing that can be included in your report The concept of multiple crossings can also be used to represent separate design alternatives of the same crossing within the same project file In previous versions of HY 8 you would either have to load them as separate files or make the incremental changes and reevaluate In vers
24. menu or from the culvert toolbar During the analysis the program completes the necessary hydraulic computations after which the overtopping performance table will be displayed A summary of flows at the crossing will be displayed including any overtopping flows if they occur While viewing the analysis the user will also be able to view individual culvert summary tables water surface profiles the tapered inlet table as well as a customized table made up of any of the parameters computed during the analysis HY8 HY8 Project gl Project i 1 Culvert Crossing Data Dg w azi Add Culvert Delete Duplicate Rename Report Generation 14 Report Generation Report Generation Once a culvert project is completed and analyzed you have the option of creating a report A report can be created for just one or multiple crossings The user can also select from the available fields which data to include and reporting what order The report file type is a rich text file rtf which can be opened in Microsoft Word for editing The report generation window is divided into the following sections Choose Crossing s to Include All crossings in the project appear here The user may select a single multiple or all of the crossings to include in the report Format Three report types are available The user may select the default standard report which includes the results in the figure below
25. oldid 65718 Contributors Cmsmemoe Jcreer Roadway Profile Source http www xmswiki com xms index php oldid 65719 Contributors Cmsmemoe Jcreer Tailwater Data Source http www xmswiki com xms index php oldid 65720 Contributors Cmsmemoe Jcreer Channel Shape Source http www xmswiki com xms index php oldid 65721 Contributors Cmsmemoe Jcreer Rating Curve Source http www xmswiki com xms index php oldid 65722 Contributors Cmsmemoe Jcreer Constant Tailwater Elevation Source http www xmswiki com xms index php oldid 65723 Contributors Cmsmemoe Jcreer Irregular Channel Source http www xmswiki com xms index php oldid 65724 Contributors Cmsmemoe EJones Jcreer Irregular Channel Error Source http www xmswiki com xms index php oldid 65725 Contributors Cmsmemoe Jcreer Culvert Data Source http www xmswiki com xms index php oldid 65727 Contributors Cmsmemoe Jcreer Shapes Source http www xmswiki com xms index php oldid 65728 Contributors Cmsmemoe Jcreer Material Source http www xmswiki com xms index php oldid 65733 Contributors Cmsmemoe Jcreer Plastic Pipe Materials Source http www xmswiki com xms index php oldid 65732 Contributors Cmsmemoe Concrete Open Bottom Arch Source http www xmswiki com xms index php oldid 65731 Contributors Cmsmemoe Jcreer South Dakota Concrete Box Source http www xmswiki com xms index php oldid 65734 Contributors Cmsmemoe Jcreer Culvert Type Source http www xmswiki com
26. outlet stations at the same elevation the program will automatically assign a slope value of 0 000001 ft ft m m for computational purposes The slope will be shown as zero in all output tables Embankment Toe Data 42 Embankment Toe Data Embankment toe data are used to describe the fill into which a culvert will be placed No culvert dimensions are provided at this point and the goal of the designer is to fit the culvert in the designed roadway cross section when geometry is provided from design drawings Once the culvert height has been entered the program will calculate the culvert invert station and elevation data see the diagram below The following parameters are defined by the user and are shown in the figure below Upstream Station Station m or ft of the upstream intersection of the stream bed or drainage channel and embankment slope Upstream Elevation Stream bed elevation m or ft at upstream station Upstream Embankment Slope Embankment slope on the upstream side of the roadway m m or ft ft Downstream Station Station m or ft of downstream intersection of the stream bed or drainage channel and embankment slope Must be greater than the upstream station Downstream Elevation Stream bed elevation m or ft at downstream station Downstream Embankment Slope Embankment slope on the downstream side of the roadway m m or ft ft Number of Barrels Program default is 1 barrel although the
27. proper relationship to the roadway in the front view When the irregular profile shape is selected the user is prompted to enter between 3 and 15 points defining the station and elevation of each point along the roadway profile The user is prompted to enter a beginning station for the roadway when viewing the culvert from the front using the Views toolbar v raAength vr ar V Roadway Elevation Length The length for a horizontal roadway is somewhat arbitrary but should reflect the top width of the water surface in the channel upstream from the culvert at the roadway elevation Roadway width includes the shoulders traffic lanes and median 21 3 3 Tailwater Data Tailwater Data Tailwater Data HY 8 provides the following options for calculating the tailwater rating curve downstream from a culvert crossing Channel Shape e Irregular Channel Rating Curve Constant Tailwater Elevation Uniform depth is used to represent tailwater elevations for both a defined channel shape and an irregular channel The cross section representing these two options should be located downstream from the culvert where normal flow is assumed to occur downstream from channel transitions for example The calculated water surface elevations are assumed to apply at the culvert outlet Channel Shape There are three available channel shapes to define the downstream tailwater channel rectangular
28. s REFERENCE Polynomial Coefficients 57 27 30 Calculator Design Series CDS 4 for TI 59 FHWA 1982 page 20 31 33 Calculator Design Series CDS 4 for TI 59 FHWA 1982 page 22 Table 5 Polynomial Coefficients Pipe Arch HY 8 Equation PIPE Inlet Configuration KE SR A BS C DIP EE F 12 CSPA proj 0 9 0 5 0 08905 0 71255 0 27092 0 07925 0 00798 0 00029 13 CSPA proj 0 9 0 5 0 12263 0 4825 0 00002 0 04287 0 01454 0 00117 14 CSPA proj 0 9 0 5 0 14168 0 49323 0 03235 0 02098 0 00989 0 00086 15 CSPA proj 0 9 0 5 0 09219 0 65732 0 19423 0 04476 0 00176 0 00012 16 CSPA mitered 0 7 0 7 0 0833 0 79514 0 43408 0 16377 0 02491 0 00141 17 CSPA mitered 0 7 0 7 0 1062 0 7037 0 3531 0 1374 0 02076 0 00117 18 CSPA mitered 0 7 0 7 0 23645 0 37198 0 0401 0 03058 0 00576 0 00045 19 CSPA mitered 0 7 0 7 0 10212 0 72503 0 34558 0 12454 0 01676 0 00081 20 CSPA headwall 0 5 0 5 0 11128 0 61058 0 19494 0 05129 0 00481 0 00017 21 CSPA headwall 0 5 0 5 0 12346 0 50432 0 13261 0 0402 0 00448 0 00021 22 CSPA headwall 0 5 0 5 0 09728 0 57515 0 15977 0 04223 0 00374 0 00012 23 CSPA headwall 0 5 0 5 0 09455 0 61669 0 22431 0 07407 0 01002 0 00054 24 RCPA h
29. singleitem collection ETD id 1623 rec 2 Getting Started HY 8 automates culvert hydraulic computations As a result a number of essential features that make culvert analysis and design easier HY 8 enables users to analyze The performance of culverts Multiple culvert barrels at a single crossing as well as multiple crossings Roadway overtopping at the crossing and Develop report documentation in the form of performance tables graphs and key information regarding the input variables New to HY 8 is the ability to define multiple crossings within a single project A crossing is defined by 1 to 6 culverts where each culvert may consist of multiple barrels In previous versions this defined the entire project However with HY 8 any number of projects may be defined within the same project The diagram below illustrates the hierarchy of a HY 8 project 0 Project Kiwanis Main Relief 1 Seven Peaks Main Within a project new crossings can be created and then for each crossing up to six culverts can be defined The Microsoft Virtual Map Locator tool has been included within HY 8 so that a roadway map or aerial photograph can be displayed and culvert crossing locations mapped as shown below Getting Started z UI Bich Ld 5 fa 5 9 m a pe 5 Oy e 5 E 1060 N pov E Dr o 5 Campus 820 N E 820 N be x E 800 N e cu X d
30. user may place multiple barrels with the same characteristics Station and Elevation Station and Elevation 5 Analysis 44 5 1 General Project Units The user has the option of entering data in US Customary or SI units HY 8 performs all calculations in US Customary units but the user may enter data and view results in SI units HY 8 will perform the necessary conversions When switching the units control all existing input parameters are converted appropriately Roadway Overtopping When the headwater elevation exceeds the elevation of the roadway overtopping will occur as shown below When overtopping is simulated the program computes the discharge for each culvert and for the roadway that will result in the same headwater elevation An overtopping analysis will be completed for every crossing and if overtopping occurs the corresponding flow values will be displayed 5 2 Head Water Computations 46 5 2 1 Inlet Control Inlet Control Computations Inlet control means that the amount of water the culvert barrel can carry is limited by the culvert entrance Flow passes through critical depth at the culvert entrance and is supercritical in the barrel There are several flow profiles possible HY 8 simulates so called Type A B C and D conditions as shown below and as described in HDS 5 These profiles are known as Type 1 A C and Type 5 B D within HY 8
31. xms index php oldid 65735 Contributors Cmsmemoe Jcreer Broken Back Culverts Source http www xmswiki com xms index php oldid 65736 Contributors Cmsmemoe Jcreer Inlet Configurations Source http www xmswiki com xms index php oldid 65737 Contributors Cmsmemoe Jcreer Inlet Depression Source http www xmswiki com xms index php oldid 65738 Contributors Cmsmemoe Jcreer Embedment Depth Source http www xmswiki com xms index php oldid 65739 Contributors Cmsmemoe EJones Jcreer Site Data Input Option Source http www xmswiki com xms index php oldid 65740 Contributors Cmsmemoe Jcreer Culvert Invert Data Source http www xmswiki com xms index php oldid 65741 Contributors Cmsmemoe Jcreer Embankment Data Source http www xmswiki com xms index php oldid 65742 Contributors Cmsmemoe Jcreer Project Units Source http www xmswiki com xms index php oldid 65747 Contributors Cmsmemoe Jcreer Roadway Overtopping Source http www xmswiki com xms index php oldid 65748 Contributors Cmsmemoe Jcreer Inlet Control Computations Source http www xmswiki com xms index php oldid 65749 Contributors Cmsmemoe Jcreer Polynomial Generation Source http www xmswiki com xms index php oldid 65750 Contributors Cmsmemoe Jcreer Polynomial Coefficients Source http www xmswiki com xms index php oldid 65751 Contributors Cmsmemoe EJones Jcreer Outlet Control Computations Source http www xmswiki com xms index php oldid 65752 Contributor
32. 1 gif Source http www xmswiki com xms index php title File HY 8imageS 1 gif License unknown Contributors Eshaw Image HY8image54 gif Source http www xmswiki com xms index php title File H Y 8image54 gif License unknown Contributors Eshaw Image HYS8IrregularChannel png Source http www xmswiki com xms index php title File HY8IrregularChannel png License unknown Contributors Cmsmemoe Image HY8image22 jpg Source http www xmswiki com xms index php title File HY8image22 jpg License unknown Contributors Eshaw Image HY8CulvertShapes jpg Source http www xmswiki com xms index php title File H Y8CulvertShapes jpg License unknown Contributors Eshaw Image HY8SideTapered SMALL jpg Source http www xmswiki com xms index php title File HY8SideTapered SMALL jpg License unknown Contributors Eshaw Image HY8SlopeTapered SMALL jpg Source http www xmswiki com xms index php title File H Y8SlopeTapered SMALL jpg License unknown Contributors Eshaw Image SingleBrokenBackCulvert png Source http www xmswiki com xms index php title File SingleBrokenBackCulvert png License unknown Contributors Cmsmemoe Image DoubleBrokenBackCulvert png Source http www xmswiki com xms index php title File DoubleBrokenBackCulvert png License unknown Contributors Cmsmemoe Image BrokenBackSteepBoundaryConditions png Source http www xmswiki com xms index php title File BrokenBackSteepBoundaryConditions png License unknown Contributors Cmsmemoe Image BrokenBack
33. 1 m s 400 ft2 s and Velocity V lt 15 m s 50 ft s Culvert rise less than or equal to 1500 mm 60 in Drop lt 4 6 m 15 ft Drop lt 3 7 m 12 ft na not applicable 88 6 1 Scour Hole Geometry Scour Hole Geometry The scour hole geometry presented in this screen represents the local scour at the outlet of structures based on soil and flow data and culvert geometry Chapter 5 of FHWA publication HEC 14 Hydraulic Design of Energy Dissipators for Culverts and Channels dated July 2006 presents the general concept and equations used by the program to compute the scour hole geometry for cohesive and cohesionless materials NOTE A soil analysis should be performed prior to running this option of the program For Cohesive soils the program requires the following parameters Time to Peak Enter the value obtained in the HYDROLOGY option of HY 8 If unknown enter 30 minutes e Saturated Shear Strength Obtained by performing test no ASTM D211 66 76 Plasticity Index Obtained by performing test no ASTM D423 36 For Cohesionless soils the program requires the following parameters Time to Peak Enter the value obtained in the HYDROLOGY option of HY 8 If unknown enter 30 minutes D16 084 801 particle diameters which represent percent of particles finer Note on Time to Peak The time of scour is estimated based upon knowledge of peak flow duration Lacking this knowledge it is recommen
34. 3 1 1 Bevel Headwall 0 2 0 5 0 1666086 0 3989353 0 06403921 0 01120135 0 0006449 0 000014566 4 Square Edge 30 75 degree flare 0 4 0 5 0 0724927 0 507087 0 117474 0 0221702 0 00148958 0 000038 Wingwall 5 Square Edge 0 degree flare 0 7 0 5 0 144133 0 461363 0 0921507 0 0200028 0 00136449 0 0000358 Wingwall 6 1 1 Bevel 45 degree flare Wingwall 0 2 0 5 0 0995633 0 4412465 0 07434981 0 01273183 0 0007588 0 00001774 EQ s REFERENCE 1 6 Hydraulic Computer Program HY 6 FHWA 1969 subroutine BEQUA 1 4 5 Hydraulic Computer Program HY 3 FHWA 1969 page 16 1 3 4 6 Calculator Design Series CDS 3 for TI 59 FHWA 1980 page 16 Table 4 Polynomial Coefficients Ellipse HY 8 Equation PIPE Inlet Configuration KE SR A BS C DIP EE F 27 CSPE headwall 0 5 0 5 0 01267 0 79435 0 2944 0 07114 0 00612 0 00015 28 CSPE mitered 0 7 0 7 0 14029 1 437 0 92636 0 32502 0 04865 0 0027 29 CSPE bevel 0 3 0 5 0 00321 0 92178 0 43903 0 12551 0 01553 0 00073 30 CSPE thin 0 9 10 5 0 0851 0 70623 0 18025 0 01963 0 00402 0 00052 31 RCPE square 0 5 0 5 0 13432 0 55951 0 1578 0 03967 0 0034 0 00011 32 RCPE grv hdwl 0 2 0 5 0 15067 0 50311 0 12068 0 02566 0 00189 0 00005 33 RCPE grv proj 0 2 0 5 0 03817 0 84684 0 32139 0 0755 0 00729 0 00027 EQ
35. 3 4 Total Discharge cfs Culvert Summary The culvert summary table shows the performance table for each culvert in the crossing Each culvert s properties can be viewed by selecting the desired culvert from the drop down list The following properties are represented in the table Total Discharge Total discharge at the culvert crossing Culvert Discharge Amount of discharge that passes through the selected culvert barrel s Headwater Elevation Computed headwater elevation at the inlet of the culvert s Inlet Control Depth Inlet control headwater depth above inlet invert Outlet Control Depth Outlet control headwater depth above inlet invert Flow Type USGS flow type 1 through 7 is indicated and the associated profile shape and boundary condition Press the Flow Types button for a summary of Flow Types Normal Depth Normal depth in the culvert If the culvert capacity is insufficient to convey flow at normal depth normal depth is set equal to the barrel height Critical Depth Critical depth in culvert If the culvert capacity is insufficient to convey flow at critical depth critical depth is set equal to the barrel height Outlet Depth Depth at culvert outlet Tailwater Depth Depth in downstream channel Outlet Velocity Velocity at the culvert outlet Tailwater Velocity Velocity in downstream channel In the table bold values indicate inlet or outlet controlling depths Within the culvert summary option the user may plot th
36. 385201009 5 878983069 1 217423128 2 463842333 7 496921363 1 167423128 2 546662495 9 473726216 1 117423128 2 634078814 11 89752361 1 067423128 2 726576563 14 88838 1 017423128 2 824723925 18 61499626 0 967423128 2 929191151 23 32377651 0 917423128 3 040775386 29 3931714 0 867423128 3 160433253 37 44519272 0 817423128 3 28932425 1 48 60550709 0 767423128 3 42886946 65 23610698 0 717423128 3 580832395 93 76009585 0 667423128 3747432593 100 0 663122364 3 762533062 Computation Direction Downstream to Upstream Location ft S1 Water Depth ft 100 7 78884205 76 62538619 6 76 01536408 5 95 75 40596369 5 9 74 79697048 5 85 74 18839865 5 8 73 58026305 5 75 72 97257915 5 7 72 36536314 5 65 71 75863195 5 6 Hydraulic Jump Calculations 70 71 15240324 5 55 70 54669552 5 5 69 94152813 5 45 69 33692135 54 6873289638 5 35 68 12947544 5 3 67 52668185 5 25 66 92454003 52 66 3230756 5 15 65 72231547 5 1 65 12228788 5 05 64 5230225 5 63 92455054 4 95 63 32690478 4 9 62 73011975 4 85 62 13423177 4 8 61 5392791 4 75 60 94530208 4 7 60 35234323 4 65 59 76044741 4 6 59 16966197 4 55 58 58003695 4 5 57 9916252 4 45 57 40448266 44 56 81866848 4 35 56 23424533 4 3 55 6512796 4 25 55 06984171 4 2 54 49000634 4 15 53 911852
37. 6062 0 0117190357464366 0 000790440416133214 0 0000226453591207209 5096 Embedded 45 degree Beveled End 0 35 0 5 0 0732498224366533 0 426296207882289 0 0825309806843494 0 0158 108288973248 0 00103586921012557 0 0000265873062363919 10 2096 Embedded Mitered End 1 5H 1V 0 9 0 075018832861494 0 404532870578638 0 0959305677963978 0 0172402567402576 0 00121896053512953 0 000033825 1697138414 Polynomial Coefficients 56 11 4096 0 9 10 5 0 086819906748455 0 362177446931189 0 048309284166457 0 00870598247307798 0 000359506993503941 2 89144278309283E 06 Embedded Mitered End 1 5H 1V 12 50 0 9 10 5 0 0344461003984492 0 574817400258578 0 204079127155295 0 0492721656480291 0 00436372397619383 0 000144794982321005 Embedded Mitered End 1 5H 1V EQ s REFERENCE 1 12 NCHRP 15 24 report Table 3 Polynomial Coefficients Box HY 8 Inlet Configuration SR A BS C DIP EE F Equation 1 Square Edge 90 degree Headwall 0 5 0 5 0 122117 0 505435 0 10856 0 0207809 0 00136757 0 00003456 Square Edge 90 amp 15 degree flare Wingwall 2 1 5 1 Bevel 90 degree Headwall 0 2 0 5 0 1067588 0 4551575 0 08128951 0 01215577 0 00067794 0 0000148 1 5 1 Bevel 19 34 degree flare Wingwall
38. 85 4 1 53 33546552 4 05 52 76093401 4 52 18835372 3 95 51 61782627 3 9 51 04946001 3 85 50 48337049 3 8 49 91968113 3 75 49 35852381 3 7 48 80003962 3 65 Hydraulic Jump Calculations 71 48 24437962 3 6 47 69170569 3 55 47 1421915 3 5 46 59602356 3 45 46 05340235 34 45 51454362 3 35 44 97967983 33 44 44906168 3 25 43 92295991 32 43 40166723 3 15 42 88550053 3 1 42 37480328 3 05 41 86994835 3 41 37134098 2 95 40 87942233 2 9 40 39467334 2 85 39 91761912 2 8 39 44883402 2 75 38 98894719 2 7 38 53864914 2 65 38 09869903 2 6 37 66993312 2 55 37 25327445 2 5 36 84974393 2 45 36 46047324 24 36 08671965 2 35 3572988334 2 3 35 39152756 2 25 35 07340226 22 34 77747182 2 15 34 50594783 2 1 34 26132798 2 05 34 04644235 2 33 86450893 1 95 33 71920038 1 9 33 61472501 1 85 33 55592549 1 8 Hydraulic Jump Calculations 72 Culvert S2 Water Depth ft Sequent Depth ft S1 Water Depth ft Figure 1 HY 8 Water Surface Profile and Sequent Depth Calculations In Figure 1 the sequent depth shown by the red line crosses the S1 water depth shown by the purple line The point of intersection is where a hydraulic jump occurs and is located at approximately 46 downstream of the inlet of the culvert HY 8 creates a combined water surface profile
39. Arch South Dakota Concrete Box User Defined Figure 1 Culvert Shapes Circular Elliptical Pipe Arch Arch Metal Box Material 29 Material The following culvert materials are available Corrugated Steel Steel Structural Plate Corrugated Aluminum Aluminum Structural Plate Reinforced Concrete PVC Smooth HDPE Corrugated PE Only certain culvert materials are available for each culvert type HY 8 assigns a default Manning s n value for the selected material but this value can be changed if desired For more information on the plastic pipes PVC HDPE and PE please see Plastic Pipe Materials Plastic Pipe Materials HY 8 7 1 has been updated to incorporate different types of plastic pipes The following types of plastic pipes and their associated inlet configurations have been added to HY 8 7 1 1 PVC a Manning s n From HDS 5 0 009 0 011 use 0 011 b Inlet Configurations i Square Edge with Headwall 1 Notes a Use HY8 Equation Number 9 b HDS5 Chart Number 1 1 c Equation for Concrete Pipe Square Edge with Headwall ii Beveled Edge 1 1 1 Notes a Use HY8 Equation Number 6 b HDS5 Chart Number 3 A c Equation for Circular pipe culvert with beveled edge 1 1 iii Beveled Edge 1 5 1 1 Notes a Use HY8 Equation Number 7 b HDS5 Chart Number 3 B c Equation for Circular pipe culvert with beveled edge 1 5 1 iv Mitered to Conform to Slope 1 Notes
40. DakotaSketch3 png Source http www xmswiki com xms index p HY8SouthDakotaSketch3 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch4 png Source http www xmswiki com xms index pl HY8SouthDakotaSketch4 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch5 png Source http www xmswiki com xms index pl HY8SouthDakotaSketch5 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch6 png Source http www xmswiki com xms index php title File H Y 8SouthDakotaSketch6 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch7 png Source http www xmswiki com xms index php title File HY 8SouthDakotaSketch7 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch8 png Source http www xmswiki com xms index php title File H Y 8SouthDakotaSketch8 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch9 png Source http www xmswiki com xms index php title File HY 8SouthDakotaSketch9 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch10 png Source http www xmswiki com xms index php title File H Y 8SouthDakotaSketch10 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch11 png Source http www xmswiki com xms index php title File H Y 8SouthDakotaSketch1 1 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch12 png Source http www xmswiki com xms index php title File H Y 8SouthDakot
41. FACE CONTROL iii IF Depression Then CW CWF calculate CREST control 2 BOX CULVERTS A See Straight inlet equations B SIDE TAPERED RECTANGULAR TRANSITION or SLOPE TAPERED i Calculate THROAT CONTROL ii Calculate FACE CONTROL iii IF Depression Then CW CWF calculate CREST control 3 PIPE ARCHES AND ELLIPSES A See Straight inlet equations 4 IRREGULAR SHAPE A See Straight inlet equations Straight Inlet Equations 1 For IRREGULAR shape X Q AC SQR RISE IF X lt 5 THEN IH A 1 X 5 RISE ELSE IH AQ 1 AQ AQ D X J 2 INO RISE 2 For all others shapes X Q SPAN SOR RISE 3 SR SR IC B C D X X X X X SR SO RISE 3 Headwater elevation IHD IH if no Depression 4 For Depression CREST headwater is checked Inlet Control Computations 52 THROAT CONTROL TAPERED INLET 1 X2 Q SPAN SOR RISE 3 2 HT RISE 1295033 3789944 0437778 4 26329E 03 1 06358E 04 X X X X FACE CONTROL SIDE TAPERED INLET 1 ZZ Q SQOR RISE 3 2 Calculate UNSUBMERGED HF 56 RISE ZZ 66667 3 Calculate SUBMERGED A For bevels 0378 ZZ ZZ 86 RISE IF HF1 RISE THEN HF HF3 IF HF1 lt RISE THEN HF 1 IF HF gt THEN HF1 B For other edges 2 0446 ZZ ZZ 84 RISE IF HF gt RISE THEN HF HF2 IF HF1 lt RISE THEN HF HF IF HF1 gt
42. H and check head on CREST B If Q Q at 5D but Q at 3D then use INLET REGRESSION EQUATIONS C If Q Q at 3D then assume HIGH FLOW INLET CONTROL i IH Q CDAHI 5 RISE ii IF no Depression THEN IHI IH For Depression HF IH and check head on CREST INLET REGRESSION EQUATIONS Q between Q at 5D and Q at 3D 1 CIRCULAR A See Straight inlet equations B SIDE TAPERED ELLIPTICAL TRANSITION THROAT CONTROL ZZ Q SQR RISE 5 Y LOG ZZ 2 30258 i IF n lt 015 THEN SMOOTH PIPE IMPROVRD INLET ii If n 22 015 then ROUGH PIPE IMPROVED INLET iii Calculate THROAT CONTROL iv Calculate FACE CONTROL v IF Depression Then CW CWF calculate CREST control C SIDE TAPERED RECTANGULAR TRANSITION or SLOPE TAPERED i Calculate THROAT CONTROL ii Calculate FACE CONTROL iii IF Depression Then CW CWF calculate CREST control 2 BOX CULVERTS A See Straight inlet equations B SIDE TAPERED RECTANGULAR TRANSITION or SLOPE TAPERED i Calculate THROAT CONTROL ii Calculate FACE CONTROL iii IF Depression Then CW CWF calculate CREST control 3 PIPE ARCHES AND ELLIPSES A See Straight inlet equations 4 IRREGULAR SHAPE Outlet Control Computations 65 A See Straight inlet equations Straight Inlet Equations 1 For IRREGULAR shape X Q AC SQR RISE IF X lt 5 THEN IH A 1 X 5 RISE ELSE IH AQ 1 AQ AG D X J 2 INO RISE 2 For all others shape
43. HT RISE 1295033 3789944 0437778 4 26329E 03 1 06358E 04 X X X X FACE CONTROL SIDE TAPERED INLET 1 ZZ Q SQOR RISE 3 2 Calculate UNSUBMERGED HF 56 RISE ZZ 66667 3 Calculate SUBMERGED A For bevels 0378 ZZ ZZ 86 RISE IF HF1 RISE THEN HF HF3 IF HF1 lt RISE THEN HF HF IF HF1 gt THEN HF HF1 B For other edges HF2 0446 ZZ ZZ 84 RISE IF HF1 gt RISE THEN HF HF2 IF HF1 lt RISE THEN HF HF1 IF HF gt HF2 THEN HF1 FACE CONTROL FOR SLOPE TAPERED INLET 1 ZZ Q BF SQR RISE 3 2 Calculate UNSUBMERGED 1 5 RISE ZZ 66667 A For bevels 0378 ZZ ZZ 7 RISE IF 1 gt RISE THEN HF IF HFI lt RISE THEN HF IF HFI gt THEN HF B For other edges HF2 0446 ZZ ZZ 64 RISE IF 1 gt RISE THEN HF HF2 IF HFI lt RISE THEN HF 1 IF gt HF2 THEN HF Inlet Control Computations 49 CREST CONTROL 1 HC 2 5 Q CW 66667 OUTLET CONTROL PROCEDURES THAT PRODUCE AN INLET CONTROL PROFILE STEP Compute critical depth dco Compute normal depth dno Compute fullflow if nomograph solution assumed 6 FFt or FFc If dno gt 95 rise assume fullflow 6 FFn If dno dco assume mild slope SEE OUTLET DAT If dno lt dco assume steep slope A If twh is gt So L rise assume fu
44. HY 8 User Manual v7 3 HY 8 Culvert Analysis Program PDF generated using the open source mwlib toolkit See http code pediapress com for more information PDF generated at Thu 06 Mar 2014 19 16 09 CET Contents Articles 1 Introduction Introduction Getting Started Differences from DOS HY 8 Limitations Vena Contracta 2 Building a Project Building a Project Locate Project Culvert Crossing Data Run Analysis Report Generation 3 Crossing Data 3 1 General Data Crossings Discharge Data 3 2 Roadway Data Roadway Data Roadway Profile 3 3 Tailwater Data Tailwater Data Channel Shape Rating Curve Constant Tailwater Elevation 3 3 1 Irregular Channel Irregular Channel Irregular Channel Error 4 Culvert Data N 10 10 10 11 13 14 16 17 17 18 19 19 20 21 21 21 22 23 24 24 25 26 4 1 Culvert Data Culvert Data Shapes Material Plastic Pipe Materials Concrete Open Bottom Arch South Dakota Concrete Box Culvert Type Broken Back Culverts Inlet Configurations Inlet Depression Embedment Depth 4 2 Site Data Site Data Input Option Culvert Invert Data Embankment Toe Data 5 Analysis 5 General Project Units Roadway Overtopping 5 2 Head Water Computations 5 2 1 Inlet Control Inlet Control Computations Polynomial Generation Polynomial Coefficients 5 2 2 Outlet Control Outlet Control Computations Exit Lo
45. Inlet Table Site Data Culvert Data Culvert Shape Plot Tailwater Data Tailwater Rating Curve Plot Roadway Data USGS Flow Types Table mmt Include All gt gt lt lt Remove All Move fields up or down Included Fields Crossing Summary Table Crossing Rating Curve Plot Culvert Summary Tables Culvert Performance Curve Water Surface Profile Plot Site Data Culvert Data Roadway Data Project Plan View Image Water Surface Profile Table Tailwater Rating Curve Plot USGS Flow Types Table Save Custom Report Type Lalo 3 Crossing Data 17 3 1 General Data Crossings Crossings The culvert crossing is where a collection of culverts can be placed A crossing may consist of single or multiple culverts and each culvert can be defined with multiple barrels A project may contain multiple crossings as seen in Figure 1 and each crossing may contain one or multiple culverts Figure 2 Single Barrel Crossing LN Multiple Barrel Crossing Roadway Channel Culvert Barrels Figure 1 Multiple Crossings in a Project Figure 2 One or More Culverts at a Crossing Discharge Data 18 Discharge Data Discharge Data There are options to enter discharge data into HY 8 Minimum Design and Maximum User Defined and Recurrence The Minimum Design and Maximum is the default option and historically was the only option available M
46. L and L Geometry design variable e L Length of the Basin Article Sources and Contributors 115 Article Sources and Contributors Introduction Source http www xmswiki com xms index php oldid 65705 Contributors Cmsmemoe Jcreer Getting Started Source http www xmswiki com xms index php oldid 65706 Contributors Cmsmemoe Differences from DOS HY 8 Source http www xmswiki com xms index php oldid 65707 Contributors Cmsmemoe Jcreer Limitations Source http www xmswiki com xms index php oldid265800 Contributors Cmsmemoe Jcreer Vena Contracta Source http www xmswiki com xms index php oldid 65709 Contributors Cmsmemoe Jcreer Building a Project Source http www xmswiki com xms index php oldid 65710 Contributors Cmsmemoe Jcreer Locate Project Source http www xmswiki com xms index php oldid 65807 Contributors Cmsmemoe Jcreer Culvert Crossing Data Source http www xmswiki com xms index php oldid 65784 Contributors Cmsmemoe Jcreer Run Analysis Source http www xmswiki com xms index php oldid 66060 Contributors Cmsmemoe Report Generation Source http www xmswiki com xms index php oldid 65714 Contributors Cmsmemoe Jcreer Crossings Source http www xmswiki com xms index php oldid 65716 Contributors Cmsmemoe Jcreer Discharge Data Source http www xmswiki com xms index php oldid 65717 Contributors Cmsmemoe EJones Jcreer Roadway Data Source http www xmswiki com xms index php
47. MildBoundaryConditions png Source http www xmswiki com xms index php title File BrokenBackMildBoundaryConditions png License unknown Contributors Cmsmemoe Image HYS8Projecting jpg Source http www xmswiki com xms index php title File H Y 8Projecting jpg License unknown Contributors Eshaw Image HY8GroovedHeadWall FINAL JPG Source http www xmswiki com xms index php title File HY 8GroovedHeadWall FINAL JPG License unknown Contributors Eshaw Image HY8GroovedProjecting FINAL JPG Source http www xmswiki com xms index php title File H Y 8GroovedProjecting FINAL JPG License unknown Contributors Eshaw Image HY8SquareEdgeHeadWall FINAL JPG Source http www xmswiki com xms index php title File H Y 8SquareEdgeHeadWall FINAL JPG License unknown Contributors Eshaw Image HY8BevelEdgeHeadWall FINAL JPG Source http www xmswiki com xms index php title File H Y8BevelEdgeHeadWall FINAL JPG License unknown Contributors Eshaw Image HY8Mitered jpg Source http www xmswiki com xms index php title File HY 8Mitered jpg License unknown Contributors Eshaw Image HY8Wingwalls FINAL JPG Source http www xmswiki com xms index php title File HY 8Wingwalls FINAL JPG License unknown Contributors Eshaw Image HY8EmbedmentDepth jpg Source http www xmswiki com xms index php title File H Y 8EmbedmentDepth jpg License unknown Contributors Eshaw Image HY8image37 gif Source http www xmswiki com xms index php title File H Y 8image37 gif License unk
48. Publication No FHW A HRT 06 138 October 2006 Effects of Inlet Geometry on Hydraulic Performance of Box Culverts H Overview and implementation The document Effects of Inlet Geometry on Hydraulic Performance of Box Culverts FHWA Publication No FHWA HRT 06 138 October 2006 describes a series of tests that were performed to obtain design coefficients for various inlet configurations on reinforced concrete box culverts The following variations in inlet configurations were tested wingwall and top edge bevels and corner fillets multiple barrels different culvert span to rise ratios and skewed headwalls The results of the tests were K M c and Y inlet control design coefficients and 5th degree polynomial coefficients required by HY 8 that were given in the FHWA document The 5th degree polynomial coefficients given in the FHWA document cannot be used directly in HY 8 because the coefficients were only developed for a HW D range between 0 5 and 2 0 HY 8 requires the polynomial coefficients to be valid between HW D values of 0 5 and 3 0 Therefore the polynomial coefficients had to be re computed using K M c and Y coefficients from the FHWA report Several recommendations were made at the end of the FHWA document Since the recommendations were a consolidation of the FHWA research these recommendations were used in HY 8 The recommendations consolidated the results of the South Dakota box culvert testing into 13 different sets of coe
49. Source http www xmswiki com xms index php oldid 65778 Contributors Cmsmemoe Jcreer Contra Costa Basin Source http www xmswiki com xms index php oldid 65779 Contributors Cmsmemoe Jcreer Hook Basin Source http www xmswiki com xms index php oldid 65780 Contributors Cmsmemoe USBR Type VI Impact Basin Source http www xmswiki com xms index php oldid 65781 Contributors Cmsmemoe Image Sources Licenses and Contributors 117 Image Sources Licenses and Contributors Image HY8image47 jpg Source http www xmswiki com xms index php title File H Y 8image47 jpg License unknown Contributors Eshaw Image HY8image49 jpg Source http www xmswiki com xms index php title File HY 8image49 jpg License unknown Contributors Eshaw Image HY8image48 jpg Source http www xmswiki com xms index php title File HY 8image48 jpg License unknown Contributors Eshaw Image HY8image59 png Source http www xmswiki com xms index php title File HY 8image59 png License unknown Contributors Cmsmemoe Image VenaContractaDiagram png Source http www xmswiki com xms index php title File VenaContractaDiagram png License unknown Contributors Cmsmemoe Image VenaContractaEql png Source http www xmswiki com xms index php title File VenaContractaEgl png License unknown Contributors Cmsmemoe Image VenaContractaEq2 png Source http www xmswiki com xms index php title File VenaContractaEq2 png License unknown Contributors Cmsm
50. Table Water Surface Profiles Tapered Inlet Table Customized Table The appearance of plots within HY 8 can be controlled by the user using the Plot Display Options Crossing Summary The crossing summary table is important in showing the balance of discharge moving through the culvert s at the crossing and over the roadway The following variables are displayed in the table Headwater Elevation the elevation of the headwater when the flow is balanced between the culvert s and roadway Total Discharge the sum of the discharge through the culvert barrel s and over the roadway Culvert 1 Discharge the balance discharge through all the barrels in the first culvert Roadway Discharge total discharge overtopping the roadway Iteration displays the number of iterations required to reach the convergence limit Note there will be a column for the discharge through each culvert in the crossing When the crossing summary table option is selected the user may also view the total rating curve for all culverts in the crossing A sample rating curve is shown in the figure below Crossing Summary 78 n gt E LLI 1 1 o 1 5 m o EIS E Total Rating Curve Performance Total Rating Curve Performance Crossing CIRCLE VELIT d f 2t eee doe ee mmm d re Praed Vo nc yo wa 3
51. aSketch12 png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch13 png Source http www xmswiki com xms index php title File H Y 8SouthDakotaSketch13 png License unknown Contributors Cmsmemoe Image OutletControlFlowTypes png Source http www xmswiki com xms index php title File OutletControlFlowTypes png License unknown Contributors Cmsmemoe Image HydraulicJumpComps png Source http www xmswiki com xms index php title File HydraulicJumpComps png License unknown Contributors Cmsmemoe Image HydraulicJumpZeroLength png Source http www xmswiki com xms index php title File HydraulicJumpZeroLength png License unknown Contributors Cmsmemoe Image HydraulicJumpTypes png Source http www xmswiki com xms index php title File HydraulicJumpTypes png License unknown Contributors Cmsmemoe Image HydraulicJumpVariables png Source http www xmswiki com xms index php title File HydraulicJumpVariables png License unknown Contributors Cmsmemoe Image HydraulicJumpCalcLength png Source http www xmswiki com xms index php title File HydraulicJumpCalcLength png License unknown Contributors Cmsmemoe Image Sources Licenses and Contributors 118 Image HydraulicJumpCalcLengthCap png Source http www xmswiki com xms index php title File HydraulicJumpCalcLengthCap png License unknown Contributors Cmsmemoe Image HY8image44 jpg Source http www xmswiki com xms index php title File HY8image44 jpg License unknown Contributors Eshaw Im
52. age HY8image45 jpg Source http www xmswiki com xms index php title File HY8image45 jpg License unknown Contributors Eshaw Image HY8image46 jpg Source http www xmswiki com xms index php title File H Y 8image46 jpg License unknown Contributors Eshaw Image HY8image41 png Source http www xmswiki com xms index php title File HY 8image41 png License unknown Contributors Cmsmemoe Image HY8image54 jpg Source http www xmswiki com xms index php title File HY 8image54 jpg License unknown Contributors Eshaw Image HY8imageS55 jpg Source http www xmswiki com xms index php title File HY 8image55 jpg License unknown Contributors Eshaw Image HY8image61 gif Source http www xmswiki com xms index php title File HY 8image61 gif License unknown Contributors Eshaw Image HY8image63 gif Source http www xmswiki com xms index php title File H Y 8image63 gif License unknown Contributors Eshaw Image HY8image9 jpg Source http www xmswiki com xms index php title File H Y 8image9 jpg License unknown Contributors Eshaw Image HYSfig7 6 jpg Source http www xmswiki com xms index php title File HY 8fig7 6 jpg License unknown Contributors Eshaw Image HY8imagel1 jpg Source http www xmswiki com xms index php title File HY8imagell jpg License unknown Contributors Eshaw Image HYS8imagel2 jpg Source http www xmswiki com xms index php title File HY 8image12 jpg License unknown Contributors Eshaw Image HYS8fig7 1 jpg Source http www xmswiki com xms ind
53. al Riveted or We Arch Box Concrete Concrete Concrete Any other Shape Any other material Corrugated Metal Riveted or We 41 4 2 Site Data Site Data Input Option Site data describe the positioning and length of the culvert within an embankment The program adjusts culvert length according to site data culvert type culvert height and depression The following options are available for entering site data Culvert Invert Data Embankment Toe Data Culvert Invert Data The culvert invert data option is used to enter known coordinates of culvert inverts This option is generally used to analyze known existing culverts Coordinates are defined by the following input as seen in the figure below Inlet Station station of culvert inlet invert Inlet Elevation elevation at culvert inlet invert Outlet Station station of culvert outlet invert must be greater than the inlet station Outlet Elevation elevation at culvert outlet invert Number of Barrels the program default is 1 although this may be changed by the user Culvert Invert Data Station and Elevation Station and Elevation Once the user defines the culvert invert data the program computes the culvert barrel length along the culvert barrel rather than horizontally between the inlet and outlet stations If a horizontal slope 096 is desired with inlet and
54. ases to change with increasing crest width Once this occurs the crest section no longer controls and may be used in analysis and construction Embedment Depth 40 Embedment Depth Embedment Depth is the depth the culvert is embedded from the invert of the culvert barrel to the top of the embedding material If an Embedment Depth greater than zero is entered HY 8 will run the culvert analysis as if the input parameters were entered as a User Defined shape If the culvert is embedded HY 8 will determine the coordinates of the shape and use these coordinates in the User Defined equation Because of this if the culvert is embedded only the User Defined Inlet Types and Inlet Configurations will be available This is a significant difference from the computations for non embedded culverts for the Circular Concrete Box Elliptical and Pipe Arch shapes For these shapes non embedded culverts use 5th degree polynomial coefficients to compute the inlet control depth However if the culvert is embedded the inlet control depth is interpolated based on a set of interpolation coefficients for User Defined culverts In HY 8 version 7 3 for embedded circular culverts HY 8 uses the 5th degree polynomial to determine the inlet control depth The coefficients used are derived from the NCHRP 15 24 report This report gives coefficients for a circular culvert that is embedded 20 40 and 50 HY 8 will linearly interpolate between the coeffi
55. by weight max Riprap Basin and Apron 109 Contra Costa Basin Contra Costa Basin The input variables required for this calculation is the following Baffle Block Height Ratio The ratio of the baffle block height to baffle block distance from the culvert EndSill Height to Maximum Depth Ratio ratio to determine the end sill height from the maximum depth Basin Width The channel width is recommended for the basin width The following figures show the design of a Contra Costa basin Profile View V L EDT DsW 3D End View Variables from the figure Contra Costa Basin 110 D Diameter of culvert Xy Outlet depth e Approximate maximum water surface depth y Basin exit velocity Vo Outlet velocity NS Exit velocity h T Height of small baffle h Height of large baffle h Height of end sill L Length from culvert exit to large baffle L Length from large baffle to end sill L Basin length Hook Basin Hook Basin The input variables required for this calculation is the following Shape of Dissipator The user can select Warped Wingwalls or Trapezoidal See illustrations below for examples Flare Angle Warped Wingwalls only Flare angle per side of the basin Ratio of Length to A hooks over Total Basin Length Warped Wingwalls only Distance from culvert exit to first row of hooks A HOOKS divided by the total lengt
56. cated outside the culvert HY 8 assumes the hydraulic jump occurs outside the culvert and a hydraulic jump is not shown in the profile If both the beginning and end of the hydraulic jump occur inside the culvert barrel the hydraulic jump is shown in the profile and is reflected in the profile computations as shown in the image above Culvert Types Newly supported culvert types Previous versions of HY 8 did not fully support CON SPAN culverts HDPE culverts or culverts installed with a natural stream bed as the bottom CON SPAN Concrete Open bottom Arch culvert types are supported in HY 8 7 3 and later HDPE plastic culvert types are supported in HY 8 version 7 1 and later Partially buried culverts or culverts with natural stream bottoms are supported in HY 8 version 7 1 and later versions Limitations Inlet control computation limitations for selected shapes User Defined Open Bottom Arch Low Profile Arch High Profile Arch and Metal Box do not use and may not have original research that describes coefficients that can be used for their inlet control equations Instead these shapes use an HW D interpolation table defined by a chart in HDS 5 that can be used to determine headwater values at various values of Q AD O 5 Broken Back Culverts Broken back culvert support Culverts with multiple slopes broken back and horizontal adverse slopes are supported in HY 8 7 3 and later versions Side and slope taper
57. cients for the level of embedment specified however if the embedment is outside the range of data the closest set of coefficients is used The polynomial coefficients are available here Polynomial Coefficients You can define top and bottom Manning s n values to handle the embedding material properties and HY 8 uses these values to run the culvert analysis Finally if you enter an embedment depth all the materials for the selected shape will still be available However the material you select will be converted to one of the two user defined materials using the following chart Shape Material Equivalent User Defined Material for embedded culverts Circular Concrete Concrete Any other material Corrugated Steel Corrugated Metal Riveted or welded Corrugated Aluminum Concrete Box Concrete Concrete Elliptical Steel or Aluminum Corrugated Metal Riveted or Welded Concrete Concrete Any other material Pipe Arch Steel or Aluminum Corrugated Metal Riveted or Welded Steel Structural Plate Aluminum Structural Plate Concrete Concrete Any other material User Defined Corrugated Metal Riveted or Welded Corrugated Metal Riveted or We Concrete Concrete Arch Open Bottom Corrugated Steel Corrugated Metal Riveted or We Corrugated Aluminum Low Profile Arch Corrugated Steel Corrugated Metal Riveted or We Corrugated Aluminum High Profile Arch Corrugated Steel Corrugated Metal Riveted or We Corrugated Aluminum Metal Box Corrugated Steel Corrugated Met
58. concept of HY 8 by simulating a very wide floodplain with extended channel points A second option is to create vertical walls to trap the flow so the depth of flow increases Previous versions of HY 8 simply spilled excess flow onto an infinitely wide floodplain resulting in a constant rating curve above the lowest cross section endpoint 4 Culvert Data 27 4 1 Culvert Data Culvert Data Culvert data are entered by selecting the Input Properties option from the Culvert menu or by right clicking on the culvert in the Project Explorer window and selecting Input Properties The following culvert data are required Shape Material Mannning s n Size Culvert Type Inlet Configurations nlet Depression HY8 crossing Culvert Culvert 1 Input Properties ng 1 Culvert Culvert 1 Project Run Single Culvert Analysis gt EF 1 Run Multiple Culvert Analysis TOS Sl Plot Results Report Wizard 114 The site data for each culvert are also entered in the culvert data portion of the culvert properties window The user has the option of entering culvert invert data or embankment toe data Shapes 28 Shapes HY 8 will perform hydraulic computations for the following culvert shapes see Figure 1 Circular Pipe Box Elliptical long axis horizontal Pipe Arch Arch Low Profile Arch High Profile Arch Metal Box Concrete Open Bottom
59. culvert ceiling h rise of enlarged culvert Variables from the figure e D Diameter of original culvert D j Diameter of enlarged culvert D Diameter of roughened section h Height of roughness element L Length from beginning of one roughness element to the beginning of the next roughness element Tumbling Flow in Circular Culverts 93 i T Variables from the figure D Diameter of original culvert T Water surface width at critical flow condition y Depth of flow USBR Type IX Baffled Apron 94 USBR Type IX Baffled Apron The input variables required for this calculation is the following Approach Channel Slope Vertical Drop Height Baffled Apron Slope Baffled Apron Width The following figure shows a USBR Type IX Baffled Apron Variables from the figure H height of the dissipator W Width of Chute 6 3 External Dissipators 96 6 3 1 Drop Structures Drop Structures Drop structures are commonly used for flow control and energy dissipation Their main purpose is to change the slope from steep to mild by placing drop structures at intervals along the channel reach Two types of Drop Structure External Dissipators are available Box Inlet Drop Structure Straight Drop Structure Box Inlet Drop Structure The input variables required for this calculation
60. ded that a time of 30 minutes be used in Equation 5 1 The tests indicate that approximately 2 3 to 3 4 of the maximum scour depth occurs in the first 30 minutes of the flow duration The exponents for the time parameter in Table 5 1 reflect the relatively flat part of the scour time relationship t gt 30 minutes and are not applicable for the first 30 minutes of the scour process 89 6 2 Internal Energy Dissipators Increased Resistance in Box Culverts The input variables required for this calculation are the following h r Ratio of roughness element height divided by hydraulic radius taken about the top of the roughness element Height of the roughened section h The following figure shows the flow regimes and variables for an increased resistance energy dissipator implemented in a circular culvert tk I k a Quasi smooth Flow b Hyperturbulent c Isolated Flow Roughness Flow Variables from the figure L Length from beginning of one roughness element to the beginning of the next roughness element h height of roughness element D diameter of roughened section opening Increased Resistance in Circular Culverts 90 Increased Resistance in Circular Culverts The input variables required for this calculation is the following L D Ratio of roughness element spacing divided by the diameter of the culvert opening at the roughness element Range 05 to 1 5
61. des top edge beveled at 45 degrees 2 3 and 4 multiple barrels and 0 degree flared wingwalls extended sides top edge beveled at 45 degrees 2 1 to 4 1 span to rise ratio Sketches 10 amp 11 0 5 0 0 degree flared 0 0745605288 0 6533033536 0 1899798824 0 0350021004 0 0024571627 0 0000642284 77 fr wingwalls extended sides crown rounded at 8 inch radius 0 and 6 inch corner fillets and 0 deeree flared wingwalls extended sides crown rounded at 8 inch radius 12 inch corner fillets Sketch 12 0 0 5 0 degree flared 0 1321993533 0 5024365440 0 1073286526 0 0183092064 0 0013702887 0 0000423592 wingwalls extended sides crown rounded at 8 inch radius 12 inch corner fillets 2 3 and 4 multiple barrels Sketch 13 0 0 5 0 degree flared 0 1212726739 0 6497418331 0 1859782730 0 0336300433 0 0024121680 0 0000655665 wingwalls extended sides crown rounded at 8 inch radius 12 inch corner fillets 2 1 to 4 1 span to rise ratio References for South Dakota Concrete Box polynomial coefficients Thiele Elizabeth A Culvert Hydraulics Comparison of Current Computer Models pp 121 126 Brigham Young University Master s Thesis 2007 Effects of Inlet Geometry on Hydraulic Performance of Box Culverts PI FHWA Publication No FHWA HRT 06 138 October 2006
62. developed by Philip L Thompson and were provided to the Federal Highway Administration FHWA for distribution HY 8 Versions 1 1 2 1 and 3 0 were produced by the Pennsylvania State University in cooperation with FHWA The HY 8 Versions 3 0 and earlier versions were sponsored by the Rural Technical Assistance Program of the National Highway Institute under Project 18B administered by the Pennsylvania Department of Transportation Version 6 1 Energy HYD and Route was produced by GKY and Associates under contract with FHWA Christopher Smemoe developed HY 8 7 0 at the Environmental Modeling Research Lab at Brigham Young University BYU under the direction of Jim Nelson of BYU and with the assistance of Rollin Hotchkiss BYU and Philip L Thompson Retired from FHWA The primary purpose of version 7 0 was to provide Windows based graphical user interface GUI for the same hydraulic calculations performed in version 6 1 of HY 8 In the course of the development all program culvert modeling functions were translated from Basic to the programming language Several minor bugs in version 6 1 were corrected in HY 8 version 7 0 Versions 7 1 7 2 and 7 3 of HY 8 were incremental updates in which several new features were included and several bugs were fixed Besides bug fixes the following new features were added to HY 8 7 1 and 7 2 Energy dissipation calculators A new culvert shape coefficient database The ability to model bur
63. e performance curve for each culvert in the crossing A sample performance curve is displayed in the figure below Culvert Summary 79 m gt T LLI _ m Performance Curve Performance Curve Culvert EX MIT 1 Inlet Control Elev Outlet Control Eley c gt peN maga em a ss po gt a e a fP so sa a 4 B 4 A r T PLAKAT T mBR 400 600 Total Discharge cfs Water Surface Profiles Water surface profile information is displayed in a table format for each of the discharge values Once a profile is selected the user may then plot and view the profile The following parameters are displayed in the water surface profiles table Total Discharge Total discharge at the culvert crossing Culvert Discharge Amount of discharge that passes through the culvert barrel s Headwater Elevation Computed headwater elevation at the inlet of the culvert Inlet Control Depth Headwater depth above inlet invert assuming inlet control Outlet Control Depth Headwater depth above inlet invert assuming outlet control Flow Type USGS flow type 1 through 7 is indicated and the associated profile shape and boundary condition Press the F
64. eadwall 0 5 0 5 0 16884 0 38783 0 03679 0 01173 0 00066 0 00002 25 RCPA grv hdwl 0 2 0 5 0 1301 0 43477 0 07911 0 01764 0 00114 0 00002 26 RCPA grv proj 0 2 0 5 0 09618 0 52593 0 13504 0 03394 0 00325 0 00013 EQ 5 REFERENCE 12 23 Calculator Design Series CDS 4 for TI 59 FHWA 1982 page 17 24 26 Calculator Design Series CDS 4 for TI 59 FHWA 1982 page 24 12 16 20 Hydraulic Computer Program HY 2 FHWA 1969 page 17 Table 6 Polynomial Coefficients Concrete Open Bottom Arch Span Rise Wingwall KE SR A BS C DIP EE F Diagram Notes Ratio Angle Inlet Configuration 2 1 0 Degrees 0 7 0 0 0 0389106557 0 6044131889 0 1966160961 0 0425827445 0 0035136880 0 0001097816 Mitered to Conform to deren Slope 2 1 Coefficients are used if the span rise ratio is less than or equal to 3 1 58 Polynomial Coefficients 2 1 45 Degrees 0 5 0 0 0 0580199163 0 5826504262 0 1654982156 0 0337114383 0 0026437555 0 0000796275 Ex 45 degree i Wingwall 2 1 Coefficients are used if the span rise ratio is less than or equal to 3 1 2 1 90 Degrees 0 5 0 0 0 0747688320 0 5517030198 0 1403253664 0 0281511418 0 0021405250 0 0000632552 Square Edge with Headwall MEME 2 1 Coefficients are used if the span rise ratio is less than or equal to 3 1 4 1 0 Degrees 0 7 0 0
65. ed inlets Broken back culverts with side and slope tapered inlets are not currently supported High slope sections The equations for broken back culverts used in HY 8 should not be applied to culvert sections with slopes greater than 55 degrees These equations are not valid for very steep slopes and will give unrealistic results Vena Contracta What is it When water is forced through a orifice opening like a sluice gate the water continues to decrease in depth as the streamline curves turn to follow the direction of travel This contraction of depth is called the Vena Contracta Vena Contracta When and where does it occur in culvert hydraulics The Vena Contracta occurs at the inlet of a culvert whenever the inlet control depth is greater than the outlet control depth These conditions are created when the tailwater is low and the culvert is short How does HY 8 handle those computations HY 8 neglects the Vena Contracta except when the culvert slope is horizontal or adverse under inlet control HY 8 will use the following equation to determine the length of the Vena Contracta L 0 5xD Where L Vena Contracta Length D Rise of Culvert HY 8 uses the following equation to determine the final depth of the Vena Contracta ye OX Where d Vena Contracta Final Depth c Vena Contracta Coefficient y Headwater Depth or Rise of the Culvert whichever is smaller inlet 10
66. egrees 2 3 and 4 multiple barrels 0 5 0 5 0 0506647261 0 5535393634 0 1599374238 0 0339859269 0 0027470036 0 0000851484 Sketch 3 30 degree flared wingwalls top edge beveled at 45 degrees 2 1 to 4 1 span to rise ratio 0 5 0 0 0518005829 0 5892384653 0 1901266252 0 0412149379 0 0034312198 0 0001083949 Sketch 4 30 degree flared wingwalls top edge beveled at 45 degrees 15 degrees skewed headwall with multiple barrels 0 5 0 0 2212801152 0 6022032341 0 1672369732 0 0313391792 0 0024440549 0 0000743575 Sketch 5 30 degree flared wingwalls top edge beveled at 45 degrees 30 degrees to 45 degrees skewed headwall with multiple barrels 0 0 2431604850 0 5407556631 0 1267568901 0 0223638322 0 0016523399 0 0000490932 Sketches 6 amp 7 0 degree flared wingwalls extended sides square edged at crown and 0 degree flared wingwalls extended sides top edge beveled at 45 degrees 0 and 6 inch corner fillets 0 5 0 0 0493946080 0 7138391179 0 2354755894 0 0473247331 0 0036154348 0 0001033337 Polynomial Coefficients Sketches 8 amp 9 0 0 5 0 degree flared 0 1013668008 0 6600937637 0 2133066786 0 0437022641 0 0035224589 0 0001078198 IU wingwalls extended si
67. emoe Image HY8image29 jpg Source http www xmswiki com xms index php title File HY 8image29 jpg License unknown Contributors Eshaw Image HY8image30 jpg Source http www xmswiki com xms index php title File HY 8image30 jpg License unknown Contributors Eshaw Image HY8image48 gif Source http www xmswiki com xms index php title File H Y 8image48 gif License unknown Contributors Eshaw Image HY8image31 jpg Source http www xmswiki com xms index php title File H Y 8image31 jpg License unknown Contributors Eshaw Image HY8image36 jpg Source http www xmswiki com xms index php title File H Y 8image36 jpg License unknown Contributors Eshaw Image HY8Crossing jpg Source http www xmswiki com xms index php title File H Y 8Crossing jpg License unknown Contributors Eshaw File HY8Crossings2 jpg Source http www xmswiki com xms index php title File H Y 8Crossings2 jpg License unknown Contributors Jcreer Image HY8Roadway jpg Source http www xmswiki com xms index php title File H Y8Roadway jpg License unknown Contributors Eshaw Image HY8Tailwater jpg Source http www xmswiki com xms index php title File HY 8Tailwater jpg License unknown Contributors Eshaw Image HY8Channel_Shape jpg Source http www xmswiki com xms index php title File HY 8Channel_Shape jpg License unknown Contributors Eshaw Image HY8image23 jpg Source http www xmswiki com xms index php title File H Y 8image23 jpg License unknown Contributors Eshaw Image HY8image5
68. es through critical depth at the culvert entrance and is supercritical in the barrel There are several flow profiles possible HY 8 simulates so called Type A B C and D conditions as shown below and as described in HDS 5 These profiles are known as Type 1 A C and Type 5 B D within HY 8 The various flow type properties may be found in HY 8 by selecting the Flow Types button from the Culvert Summary Table and are shown below Because the flow in the barrel is supercritical outlet losses and friction losses are not reflected in the headwater elevation The headwater elevation is a function of the entrance size shape and culvert type The computed inlet control headwater elevation is found by accessing the results of scaled physical model tests The logic for determining what inlet flow control type prevails is shown below from the original HY 8 help file UNSUBMERGED INLET SUBMERGED INLET CENE r ji 2 Flow Type 1 Flow Type 5 Outlet Control Computations 64 Inlet Control Logic DETERMINE APPLICABLE INLET CONTROL EQUATION 1 IF circle or box with IMPROVED INLETS then use INLET equations 2 For Straight previously called conventional INLETS A If Q is Q at 5D then assume LOW FLOW INLET CONTROL i calculate CRITICAL DEPTH DCO ii calculate Section Properties iii VH Q 2 64 4 iv IH DCO LMULT 1 KELOW VHCOEF IF no Depression THEN IH For Depression HF I
69. ex php title File HY8fig7 1 jpg License unknown Contributors Eshaw Image HYSfig7 4 jpg Source http www xmswiki com xms index php title File HY8fig7 4 jpg License unknown Contributors Eshaw Image HY8image6 jpg Source http www xmswiki com xms index php title File HY 8image6 jpg License unknown Contributors Eshaw Image HY8imagel3 jpg Source http www xmswiki com xms index php title File HY 8image13 jpg License unknown Contributors Eshaw Image HY8fig114BoxDrop png Source http www xmswiki com xms index php title File HY 8fig114BoxDrop png License unknown Contributors Cmsmemoe Image HY8image20 jpg Source http www xmswiki com xms index php title File HY 8image20 jpg License unknown Contributors Eshaw Image HY8image21 jpg Source http www xmswiki com xms index php title File HY8image21 jpg License unknown Contributors Eshaw Image HY8image7 jpg Source http www xmswiki com xms index php title File HY 8image7 jpg License unknown Contributors Eshaw Image HY8fig8 3 BRtype3 jpg Source http www xmswiki com xms index php title File H Y 8fig8 3 BRtype3 jpg License unknown Contributors Eshaw Image HY8image27 jpg Source http www xmswiki com xms index php title File HY 8image27 jpg License unknown Contributors Eshaw Image HY8imagel4 jpg Source http www xmswiki com xms index php title File HY 8image14 jpg License unknown Contributors Eshaw Image HY8imagel5 jpg Source http www xmswiki com xms
70. fficients called Sketches which represent different inlet conditions The HY 8 developers further consolidated the results into 10 sets of inlet configurations that were added as a South Dakota Concrete Box Culvert type in HY 8 For information on the exact coefficients used and to view diagrams showing the different culvert configurations that were implemented in HY 8 see the help describing the HY 8 South Dakota Concrete Box polynomial coefficients References 1 http www fhwa dot gov publications research infrastructure hydraulics 06138 Culvert 33 Culvert Five culvert types are supported in HY 8 Straight Side Tapered Slope Tapered Single Broken back Double Broken back Straight Straight inlets are those for which no special or additional modification is made by the manufacturer or when constructed in the field Straight inlets for corrugated metal pipes CMP include thin edge projecting pipes mitered to conform to the fill slope or pipes with a headwall Straight inlets for concrete pipes and boxes include the standard groove end section pipe only and inlets with a headwall and or wingwall Flared end sections fit to either CMP or concrete are also considered straight inlets Since beveling the entrance is so common a beveled entrance appears on the straight inlet menu for HY 8 but a beveled inlet is technically called a tapered inlet Side Tapered The side tapered op
71. from the two profiles If you assume that the length of the hydraulic jump is zero the jump would be a vertical line An example of a water surface profile for a hydraulic jump assuming zero jump length is shown in Figure 2 Culvert Combined Profiles Figure 2 Water Surface Profile Assuming a Jump Length of Zero Hydraulic Jump Calculations 73 Once HY 8 determines that a jump occurs and the jump s location HY 8 determines the length of the jump and applies that length to the profile Before determining the length however HY 8 must first determine the type of hydraulic jump so the appropriate equation can be used for computing the length Hydraulic Jump Types In HY 8 hydraulic jumps are divided into 3 different types A B and C See Figure 3 Type jumps occur on a flat slope and this condition often occurs at the downstream section of a broken back culvert if a hydraulic jump did not occur in the steep section of the culvert Type B jumps only occur in broken back culverts where the jump starts in the steep section of the culvert but finishes in the downstream section of the culvert Type C jumps could occur in any sloped culverts Hydraulic Jump Type B Over slope Break Hydraulic Jump Type A Flat Figure 3 Hydraulic Jump Types used in HY 8 Determining the Length of a Hydraulic Jump HY 8 uses equations determined by Bradley and Peterka 1957 and Hager 1992 as shown in the fo
72. gher headwater elevation than the culvert throat The user must continue to increase the face width and or the crest width in the case of a mitered face and run the analysis until the headwater depth ceases to change with increasing face width and crest width in the case of a mitered face Once this occurs the face section and or the crest section no longer controls and may be used in analysis and construction Detailed information pertaining to slope tapered inlets can be found in FHWA Publication HDS 5 and accessed from the Help menu Culvert Type 35 Slope Tapered Face Section Plan Broken Back Culverts Overview of Broken Back Culverts Broken back culverts have one or more changes in slope along the length of the culvert HY 8 supports single and double broken back culverts meaning one or two changes in slope In this manual the sections for a single broken back culvert are referred to as Upper and Runout sections The sections for a double broken back culvert are referred to as Upper Steep and Runout sections Broken back culverts are used to save on excavation costs or to force a hydraulic jump for energy dissipation and prevent scour in the channel downstream from the culvert Broken Back Culverts 36 Broken Back Culvert Computation Approach To analyze a broken back culvert HY 8 computes each section as a single culvert HY 8 determines the order that eac
73. h of the basin Ratio of Width to A hooks over Total Basin Length Warped Wingwalls only Distance between hooks in the first row divided by the basin width at the first row Ratio of Length to B Hooks over Total Basin Length Warped Wingwalls only Distance from culvert exit to second row of hooks B HOOKS divided by the total length of the basin Width for the Downstream End of the Basin Warped Wingwalls only Basin Side Slope Trapezoidal shape only The user can select either 1 5 1 or 2 1 Basin Bottom Width Trapezoidal shape only The next two figures show a hook basin with warped wingwalls Hook Basin 111 Lg Lg lx 3 3 c 3 D WINGWALLS 6 VERTICAL SLOPE Y 1 SLOPE 1 1 SLOPE 1 1 Variables from the figure W Outlet width W i Width at first hooks W Distance between first hooks row A W lateral spacing between A and B hook W Width of hooks _ Width of slot in end sill W Bm approximately channel width h Height of end sill h Height to top of end sill 5 h e Height to top of warped wingwall Y Equivalent depth U N L Distance to first hooks L Distance to second hooks row B L Basin length Hook Basin 112 m hy Variables from the figure Angle of radius r radius h m height to center of radius h Height to point h Height to top of radi
74. h section is calculated based on the slopes of each section A culvert is steep if the normal depth of flow is less than critical depth and it is mild if normal depth is greater than critical depth The following table shows the computational order for single broken back culverts Please note that the order is only the initial computation If necessary some sections are recomputed with updated boundary conditions The computation order is shown with the following abbreviations U Upper and Runout Slope Steep or Mild Check for Hydraulic Jumps Order Upper Lower Upper Lower Steep Steep X X UR Steep Mild X X UR Mild Steep X RU Mild Mild RU The following table shows the computational order for double broken back culverts Please note that the order is only the initial computation If necessary some sections are recomputed with updated boundary conditions The computation order is shown with the following abbreviations U Upper S Steep and R Runout Slope Steep or Mild Check for Hydraulic Jumps Order Upper Middle Lower Upper Middle Lower Steep Steep Steep X X X USR Steep Steep Mild X X X USR Steep Mild Steep X X X RSU Steep Mild Mild X X X URS Mild Steep Steep X X SRU Mild Steep Mild X X SRU Mild Mild Steep X RSU Mild Mild Mild RSU To determine the water surface profile of
75. hannel Sr Slope of the transition e S s Slope leaving the basin Stilling Basins 101 Z ground elevation at the culvert outlet Z ground elevation at the basin entrance Z ground elevation at the basin exit Z Elevation of basin at basin exit sill Length of transition from culvert outlet to basin L Total basin length L Length of the bottom of the basin Ls Length of the basin from the bottom of the basin to the basin exit sill TS Tailwater depth leaving the basin Warning for Stilling Basin Width Since the maximum basin width is a function of basin depth the maximum width may decrease as the program increases the basin depth while converging on a solution Therefore the maximum basin width may fall below the user s first choice for basin width In this case the user will be prompted for a new basin width USBR Type III Stilling Basin The only input variable required for this calculation is the following Basin Width Chute Variables from the figure W width of the chute blocks W space between chute blocks e h height of the chute blocks W width of the chute blocks USBR Type III Stilling Basin 102 e W 4 space between chute blocks h height of the baffle blocks e h go height of the end sill L Length of the bottom of the basin d a Conjugate depth USBR Type IV Stilling Basin The onl
76. hat a tailwater depth can be computed from the rating curve Rating Curve Elevation ft 100 000 100 614 100 973 101 284 101 572 101 845 102 105 102 360 102 608 102 852 103 091 Constant Tailwater Elevation 23 Constant Tailwater Elevation A constant tailwater elevation means that the tailwater elevation entered remains constant for all flows When using this option a channel invert elevation generally the same as the downstream invert of the culvert is required so that a tailwater depth can be computed A constant tailwater elevation may represent for example the design elevation of a lake bay or estuary into which the culvert s discharge 24 3 3 1 Irregular Channel Irregular Channel An irregular channel cross section option defines a channel using the channel slope and the station elevation and Manning s n at each input coordinate point The number of coordinates allowed is unlimited but using more coordinates will take longer to compute the results coordinates and n values may be copied from Microsoft Excel and pasted into the table After all data have been entered the user can plot and view the channel cross section looking downstream Irregular Taitwater Channel File Browse for existing TW fle Import Ta water Channel Slope of tailwater channel 0 0010 Number of cross sec points 5 Irregular Channel Cross Section Elevation ft
77. ied embedded culverts The Utah State University exit loss equation was added as an option when computing outlet losses Modeling of plastic pipes Research was conducted relating to sequent depth computations for hydraulic jump computations Several improvements and fixes were made to the HY 8 report generation tools OQ tn Section property matrix of 10 points for interpolation was replaced with direct computation of section properties for each discharge Christopher Smemoe and Eric Jones at Aquaveo LLC developed HY 8 7 3 with help from Rollin Hotchkiss BYU and Philip L Thompson Retired from FHWA The following new features were added to HY 8 7 3 The profile computation code was rewritten to increase program stability and efficiency Capability was added to model hydraulic jumps and their lengths in culverts Capability was added to model broken back culverts and hydraulic jump locations lengths in broken back culverts Ability to model horizontal and adverse slopes was added WN Two new culvert types were added to the culvert shape coefficient database Concrete open bottom arch CON SPAN and South Dakota prefabricated reinforced concrete box culverts Several graduate students contributed to both the theory and programming efforts of HY 8 Brian Rowley assisted in the development of version 7 0 and 7 1 while a graduate student at BYU Elizabeth Thiele compared several culvert hydra
78. index php title File HY 8image15 jpg License unknown Contributors Eshaw Image HY8fig9 1CSU jpg Source http www xmswiki com xms index php title File HY 8fig9 1CSU jpg License unknown Contributors Eshaw Image HYS8fig9 2CSU jpg Source http www xmswiki com xms index php title File HY 8fig9 2CSU jpg License unknown Contributors Eshaw Image HYS8fig9 3sketch jpg Source http www xmswiki com xms index php title File HY8fig9 3sketch jpg License unknown Contributors Eshaw Image HY8fig101RiprapProfile png Source http www xmswiki com xms index php title File HY 8fig101RiprapProfile png License unknown Contributors Cmsmemoe Image HY8fig101RiprapPlan png Source http www xmswiki com xms index php title File HY 8fig101RiprapPlan png License unknown Contributors Cmsmemoe Image HY8imagel6 jpg Source http www xmswiki com xms index php title File HY 8image16 jpg License unknown Contributors Eshaw Image HYS8fig98 png Source http www xmswiki com xms index php title File HY 8fig98 png License unknown Contributors Cmsmemoe Image HY8fig98Hook png Source http www xmswiki com xms index php title File HY 8fig98Hook png License unknown Contributors Cmsmemoe Image HY8fig912HookTrapHor png Source http www xmswiki com xms index php title File HY 8fig9 12HookTrapHor png License unknown Contributors Cmsmemoe Image HY8fig911HookTrap png Source http www xmswiki com xms index php title File HY 8fig9 1 1HookTrap png License unknown Contribut
79. inimum Design and Maximum HY 8 will perform culvert hydraulic calculations based on the input minimum design and maximum discharge values Calculations comprising the performance curve are made for ten equal discharge intervals between the minimum and maximum values A user may input a narrower range of discharges in order to examine culvert performance for a discharge interval of special interest MINIMUM DISCHARGE Lower limit used for the culvert performance curve Can be edited to a number greater than 0 DESIGN DISCHARGE Discharge for which the culvert will be designed Always included as one of the points on the performance curve MAXIMUM DISCHARGE Upper limit used for the culvert performance curve User Defined The user first specifies the number of flows they wish to enter The user then enters the flows in ascending order smallest flows at the top highest at the bottom The user can assign a name to a flow if desired If no name is given the name column will not be shown in the results or report Recurrence The user simply specifies the flow next to the recurrence year The user does not need to enter all the years in the table and any flows that are left at zero will not show up in the results or report 19 3 2 Roadway Data Roadway Data When defining the roadway data for the culvert the following parameters are required Roadway Profile Roadway Station Crest Length Cres
80. ion ClipBoard C File B C Printer Cancel No Specific Size Millmeters C nches C Points Width 000 586 Units E View Values Inlet Control Elev 0 0 TOS 100 0 1117 371417357 200 0 1117 4223636716 300 0 1117 5157492923 400 0 1117 6362476259 500 0 1117 7850639092 600 0 1117 9853423838 700 0 1118 231792888 800 0 1118 2419600918 10 900 0 1118 4788871304 A COO Controlling Plot Display Options 85 Zooming and Panning To zoom in on a part of a plot drag a box over the area you wish to see There is no zoom out tool To view the entire image right click on the plot and select Frame Plot You can also view the plot in Full Screen mode by right clicking on the plot and selecting Maximize Plot To exit Full Screen mode press escape 86 6 Energy Dissipation Energy Dissipators Hydraulic Engineering Circular No 14 HEC 14 describes several energy dissipating structures that can be used with culverts HEC 14 describes procedures that can be used to compute scour hole sizes and design internal and external dissipators It outlines the following steps that can be used when designing a culvert Step 1 Identify Design Data Step 2 Evaluate Velocities y Step 3 Evaluate Outlet Scour Hole Y Step 4 Design Alternative Energy Dissipators Step 5 Select Energy Dissipator HEC 14 also describes the energy di
81. ion 7 0 of HY 8 you have the option of copying a crossing and then you can make the change you wish to evaluate The project explorer then makes it easy to toggle back and forth between the alternative crossing designs Order of Input The MS DOS versions of HY 8 presented the input as a series of linear input screens The order always began with the discharge followed by the culvert information followed by the tailwater data and ending with the roadway information In this new Windows compatible version of HY 8 all of the input necessary to analyze a single crossing is presented in the same input screen However the grouping of the information has been organized into the crossing information and the culvert information The discharge tailwater and roadway data are unique to the crossing while the culvert shape inlet conditions and site data define a culvert within the crossing This grouping and therefore subsequent tabbing through the main input screen does not follow the same linear progression of input as previous versions of HY 8 Execution of SINGLE and BALANCE The MS DOS versions of HY 8 contained separate analysis functions for computing a culvert performance rating curve SINGLE and a roadway overtopping analysis BALANCE that included the effects of all culverts within a crossing When running SINGLE HY 8 assumed that overtopping was not possible even though roadway data were defined In HY 8 version 7 0 all culvert analy
82. ired head on the weir crest to pass the design flow y Tailwater depth above the floor of the stilling basin Sill height Straight Drop Structure 98 Straight Drop Structure The input variables required for this calculation is the following Drop Height The vertical drop height from structure crest to channel bottom In the final design the drop height to the basin bottom is given The difference between the two is the amount the basin is suppressed below the channel bottom New Slope The slope that will exist on the channel once the drop structures are in place the new slope must be subcritical The following figures show straight drop structures AERATED NAPPE Variables from the figure q Design Discharge Critical depth hy Drop from crest to stilling basin floor s duy Pool depth under the nappe de ms Depth of flow at the tow of the nappe or the beginning of the hydraulic jump Tailwater depth sequent to y2 e L 0 Distance from the headwall to the point where the surface of the upper nappe strikes the stilling basin floor L Distance from the upstream face of the floor blocks to the end of the stilling basin Straight Drop Structure 99 TOP SLOPE TO i FLOOR BLOCKS LONGITUDINAL SILL OPTIONAL PLAN Variables from the figure Critical depth hy Drop from crest to stilling basin floor h Vertical drop between the ap
83. is the following H Desired drop height Must be between 2 and 12 ft or between 0 6 and 3 7 m New Slope The slope that will exist on the channel once the drop structures are in place The new slope must be subcritical Box Length Length of box inlet USER S CHOICE W Width of box inlet Must fit criteria 25 lt Hy W lt 1 W Width of the Downstream End of Stilling Basin This must be equal to or larger than the culvert width Flare of Stilling Basin 1 Lateral Z long This value must be greater than or equal to 2 which is to say 1 lateral 2 Long Length from Toe of Dike to Box Inlet If a dike is used the distance from the toe of the dike to the box inlet must be entered If no dike is used enter a value of 100 ft or 30 48 m for this distance The following figure shows a plan and side view of a box inlet drop structure Box Inlet Drop Structure 97 60 8 gt 45 Variables from the figure W E Width of the upstream end of the basin W Width of box inlet crest W Width of the downstream end of the basin W Distance from the toe of dike to the box inlet 4 L Length of box inlet N L Minimum length for the straight section L Minimum length for final section potentially flared H Drop from crest to stilling basin floor h Vertical distance of the tailwater below the crest h Height of the end sill y Requ
84. le The equations used to determine the sequent depth vary by shape and are detailed in Nathan Lowe s thesis Lowe 2008 Sequent Depths are not adjusted for slope or hydraulic jump type see Hydraulic Jump Types An example of a profile set and sequent depth calculations from a box culvert is given in Table 1 and plotted in Figure 1 The subcritical depth is shown extending above the crown of the culvert to show the hydraulic grade line for comparison purposes Once HY 8 concludes the hydraulic jump calculations the flow profile is modified to be contained within the culvert barrel Table 1 Parameters of culvert used for example Parameter Value Units Culvert Shape Box Rise 6 0 ft Span 6 0 ft Length 100 0 ft Flow 80 0 cfs Table 2 HY 8 Water Surface Profile and Sequent Depth Calculations Hydraulic Jump Calculations Computation Direction Upstream to Downstream Location ft SZ Water Depth ft Sequent Depth ft 0 1 767423128 1 767423128 0 029316423 1 717423128 1 818384336 0 121221217 1 667423128 1 871344458 0 284143628 1 617423128 1 926427128 0 528025114 1 567423128 1 983769228 0 86466911 1 517423128 2 043522893 1 308192917 1 467423128 2 105857905 1 87561876 1 417423128 2 17096453 2 587657601 1 367423128 2 239056945 3 469764745 1 317423128 2 310377355 4 553586554 1 267423128 2
85. le and are shown in Figure 4 L Length of the hydraulic jump on a flat slope ft or m y Sequent depth at the upstream end of the hydraulic jump ft or m y Sequent depth at the downstream end of the hydraulic jump ft or m Fr Froude number at the upstream end of the hydraulic jump Channel angle of repose in radians Arctan channel slope L Length of the hydraulic jump on a sloping channel ft or m z Distance from the invert of the flat part of the channel to the channel invert at the beginning of the jump ft or m h Depth of water on a flat slope after the jump ft or m Figure 4 Variable definitions used in hydraulic jump length computations HY 8 determines the length of the jump and modifies the profile to an angled transition to the subcritical flow rather than a vertical transition The beginning of the jump is assumed to be the location previously determined as the jump location The end of the jump is the beginning of the jump plus the jump length If the end of the jump is outside of the culvert the jump is assumed to be swept out This may or may not happen but is considered to be conservative This assumption means HY 8 reports less hydraulic jumps than may actually occur Example hydraulic jump length calculations are shown in Table 4 The profile showing the hydraulic jump with the jump length applied is shown in Figure 5 Table 4 Sample Hydraulic Jump Length Calculations Parameter Value
86. llflow 4 FFt ON B If twh is gt rise outlet submerged assume inlet unsubmerged C If twh is rise outlet is unsubmerged assume inlet unsubmerged i Assume headwater oh inlet control headwater ih Calculate S2 curve 1 S2n for outlet depth If oh gt rise inlet submerged 5 S2n ii If twh gt headwater tailwater drowns out jump Calculate curve 3 MIt If culvert flows part full 7 Mit FLOW SUBMERGED CONTROL T OUTLET FULL CALC DEPTH 6B3b Inlet control means that the amount of water the culvert barrel can carry is limited by the culvert entrance Flow passes through critical depth at the culvert entrance and is supercritical in the barrel There are several flow profiles possible HY 8 simulates so called Type A B C and D conditions as shown below and as described in HDS 5 These profiles are known as Type 1 A C and Type 5 B D within HY 8 The various flow type properties may be found in HY 8 by selecting the Flow Types button from the Culvert Summary Table and are shown below Because the flow in the barrel is supercritical outlet losses and friction losses are not reflected in the headwater elevation The headwater elevation is a function of the entrance size shape and culvert type The computed inlet control headwater elevation is found by accessing the results of scaled physical model tests The logic for determining what inlet flow control type prevails is sho
87. llowing table Complete information about the lengths of hydraulic jumps does not exist in the literature These portions of the table where equations representing the hydraulic jump length are not available are denoted with a In instances where an equation has not been determined an explanation of how HY 8 computes the length is shown Table 3 HY 8 Hydraulic Jump Length Equations Culvert Flat Slope Type A Sloped Culvert Type C Jump Over Slope Break Type B Shape Circular Li Use box equation Use box equation B Fr 1 4 220 y tanh 5 Lj L 3 First solve Fry 11 3 1 3l a z1 h a Then if Fr1 gt Fry L L Otherwise if lt Fry 7 1 L g 2 6E lt exp 1 6E 5g 5 6E exp 1 6E Fri 2 where E 21 ha Ellipse Use longer of circular and box Use box equation Use box equation equations Pipe Arch Use longer of circular and box Use box equation Use box equation equations User Use longer of circular and box Use box equation Use box equation Defined Other equations Hydraulic Jump Calculations 74 In the above table you can see that the literature is incomplete for the jump lengths of several of the shapes supported in HY 8 Further research is required for a more accurate analysis The following variables are used in the above tab
88. low Types button for a summary of Flow Types Length Full Length of culvert that is flowing full Length Free Length of culvert that has free surface flow Last Step Last length increment calculated in profile Mean Slope Last mean water surface slope calculated First Depth Starting depth for water surface profile Last Depth Ending depth for the water surface profile While viewing the water surface profiles table the user may plot any of the profiles by selecting the desired profile in the table and clicking the water profile button in the window Below is a sample water surface profile for a circular culvert Water Surface Profiles 80 L Water Surface Profile Water Surface Profile Culvert CIRCLE 1 m Y Culvert Barrel Embankment Critical Profile T T p 14233 3 T 4 p Profile Elevation ft 4 e emm om Culvert Station ft Tapered Inlet The tapered inlet table is designed to be used with tapered inlets and shows the headwater elevation at the culvert inlet based on different controls such as the crest face and throat The following parameters are computed and displayed Total Discharge Total discharge at the culvert crossing Culvert Discharge Amount of discharge that passes through the culvert barrel s Headwater Elevation Computed headwater elevation at the inlet s of the culvert s
89. mbling flow dissipators Steel L 2 h 2 Variables from the figure L Length from beginning of one roughness element to the beginning of the next roughness element h Height of roughness element e h i Distance from top of dissipator to ceiling of culvert h Height of splash shield on ceiling of culvert h Culvert rise dE um Tailwater depth V4 Ve ag Variables from the figure L i Length from beginning of one roughness element to the beginning of the next roughness element L Transition Length h Height of roughness element JE tare Critical depth slope of the culvert bottom expressed in degrees e jet angle taken as 45 degrees Tumbling Flow in Circular Culverts 92 Tumbling Flow in Circular Culverts The only input variable required for this calculation is the following Diameter of enlarged culvert The following figures show implementations of tumbling flow within circular culverts along with the variables used to design the energy dissipator E jS Variables from the figure e D Diameter of original culvert V Tailwater velocity y Tailwater depth L Length from beginning of one roughness element to the beginning of the next roughness element h Height of roughness element e h T length from top of roughness element to enlarged culvert ceiling h height of splash shield on enlarged
90. nd sent to a text file however the ability to include graphs and take advantage of formatting in modern word processing programs was lacking The Report Generation tools in HY 8 7 0 are customizable include many options for plots and are saved in rich text format rtf The primary target is an MS Word document however the rtf format is readable by most Windows based word processing programs A few limitations exist with this first version and will likely be improved in future documents These limitations stem from a problem of placing tables and graphs within document text In this first version each time a table or graph is saved a new page is started This is because of a limitation in the library routines being used that do not allow tables and graphs to be docked in line with text After exporting a report you can manually dock tables in MS Word by selecting the table frame and then right clicking on the frame border and choosing the Format Frame option In this screen select the Lock Anchor option For graphs you will select the graphic and right click inside choosing the Format Picture option In this screen choose the Layout tab and then the In Line with Text option Once these options are set for tables and graphs new page sections can be deleted and the tables and graphs placed continuously It is our intention that this limitation within the library functions used for report generation will be corrected soon Limitations Limitati
91. nkment and prevents embankment material from falling into the culvert e NOTE HDS 5 notes that Flared end sections made of either metal or concrete are the sections commonly available from manufacturers From limited hydraulic tests they are equivalent in operation to a headwall in both inlet and outlet control Some end sections incorporating a closed taper in their design have a superior hydraulic performance These latter sections can be designed using the information given for the beveled inlet Inlet Depression The depression of a culvert is the vertical drop of the inlet control section below the stream bed An inlet depression is defined by entering a value for each of the following items see drawing below Depression Depression Slope Crest Width DEPRESSION The vertical drop of inlet control section below the stream bed DEPRESSION SLOPE Slope between the stream bed and the face invert The depression slope must be set between 2 1 and 3 1 CREST WIDTH Length of weir crest at the top of the depression slope Designing the crest width becomes an iterative process in HY 8 as the user must select a crest width wide enough so that it does not control the headwater calculations If the selected crest width is not wide enough the crest section will produce a higher headwater elevation than the culvert throat The user must continue to increase the crest width and run the analysis until the headwater depth ce
92. nown Contributors Eshaw Image HY8SitedataEmbankmentToe jpg Source http www xmswiki com xms index php title File HY8SitedataEmbankmentToe jpg License unknown Contributors Eshaw Image HY8Overtopping JPG Source http www xmswiki com xms index php title File H Y8Overtopping JPG License unknown Contributors Eshaw Image InletControlFlowTypes png Source http www xmswiki com xms index php title File InletControlFlowTypes png License unknown Contributors Cmsmemoe Image HY8Inlet_Control_Chart jpg Source http www xmswiki com xms index php title File HY 8Inlet_Control_Chart jpg License unknown Contributors Eshaw File 0DegreeWingwallConspanCulvertDiagram png Source http www xmswiki com xms index php title File 0DegreeWingwallConspanCulvertDiagram png License unknown Contributors Cmsmemoe File d5DegreeWingwallConspanCulvertDiagram png Source http www xmswiki com xms index php title File 45DegreeWingwallConspanCulvertDiagram png License unknown Contributors Cmsmemoe File 90DegreeWingwallConspanCulvertDiagram png Source http www xmswiki com xms index php title File 90Degree WingwallConspanCulvertDiagram png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch1 png Source http www xmswiki com xms index p HY8SouthDakotaSketchl png License unknown Contributors Cmsmemoe Image HY8SouthDakotaSketch2 png Source http www xmswiki com xms index p HY8SouthDakotaSketch2 png License unknown Contributors Cmsmemoe Image HY8South
93. o if actual stationing is not known or important Lateral stations for culverts are defined from the beginning left side of the roadway and elevations taken from the upstream invert elevation parameter Cross section information is generally provided at the downstream end of the culvert but the front view represents the upstream view and because there is no cross section defined for the upstream end of the culvert no cross section is plotted for the front view You can change the station of a culvert once entered in the same way by right clicking in the front view plot window and choosing the menu option to edit the culvert station Background Map Because multiple crossings can be defined within a single HY 8 project there is an option to create a background map This map is only a picture and can be defined from any bitmap bmp file If you are connected to the internet you may search for a roadway or aerial view map online and save the result as your background map You may also screen capture any image i e a CAD drawing and save that image as a bitmap bmp file to import and use for your map as well The map is only used for reference purposes and it or locations defined for culverts have no bearing on any calculations Currently the map is sent to the report document but you can cut and paste it into the file by capturing it form the screen Report Generation With previous versions of HY 8 a comprehensive table could be generated a
94. oldid 65765 Contributors Cmsmemoe Jcreer Tumbling Flow in Box Culverts Source http www xmswiki com xms index php oldid 65766 Contributors Cmsmemoe Jcreer Tumbling Flow in Circular Culverts Source http www xmswiki com xms index php oldid 65767 Contributors Cmsmemoe USBR Type IX Baffled Apron Source http www xmswiki com xms index php oldid 65768 Contributors Cmsmemoe Jcreer Drop Structures Source http www xmswiki com xms index php oldid 65769 Contributors Cmsmemoe Jcreer Box Inlet Drop Structure Source http www xmswiki com xms index php oldid 65770 Contributors Cmsmemoe Jcreer Straight Drop Structure Source http www xmswiki com xms index php oldid 65771 Contributors Cmsmemoe Jcreer Stilling Basins Source http www xmswiki com xms index php oldid 65772 Contributors Cmsmemoe Jcreer USBR Type III Stilling Basin Source http www xmswiki com xms index php oldid 65773 Contributors Cmsmemoe Jcreer USBR Type IV Stilling Basin Source http www xmswiki com xms index php oldid 65774 Contributors Cmsmemoe Jcreer Saint Anthony Falls SAF Stilling Basin Source http www xmswiki com xms index php oldid 65775 Contributors Cmsmemoe Jcreer Streambed Level Structures Source http www xmswiki com xms index php oldid 65776 Contributors Cmsmemoe Jcreer Colorado State University CSU Rigid Boundary Basin Source http www xmswiki com xms index php oldid 65777 Contributors Cmsmemoe Jcreer Riprap Basin and Apron
95. omputations are supported in HY 8 7 3 and later versions Computed outlet velocity and tailwater elevation The user should be aware that when the tailwater elevation exceeds the elevation of the top of the culvert outlet the barrel may or may not flow full at the outlet HY 8 determines a water profile using the direct step method in each direction and the sequent depth associated with each of the steps If the sequent depth associated with the forward profile matches the depth along the backward profile through the culvert a hydraulic jump occurs and the length of the jump is calculated from that location Since the lengths of jumps have not been tested for all culvert sizes and slopes only a limited set of equations are available for computing the lengths of jumps in HY 8 More information on the jump length computations is available in the section of this manual that describes hydraulic jump computations water surface profile for this case is shown below Limitations Crossing BOX Design Discharge 80 0 cfs Culvert BOX 1 Culvert Discharge 80 0 cfs Elevation ft 20 0 20 40 60 80 100 120 Station ft In this case the hydraulic jump length computed by HY 8 may or may not be correct since the equation used to compute hydraulic jump length is for box culverts only but is applied to all the other possible HY 8 culvert shapes If a hydraulic jump occurs inside the culvert and the end of the hydraulic jump is lo
96. on do not match exit losses obtained from experimental studies by the researchers at Utah State University USU has formulated an alternative expression for determining exit losses that uses the Borda Carnot equation This equation was originally developed for sudden expansions in pressurized pipes but was found to give an accurate representation of culvert exit losses by USU s experimental studies Two useful forms of this expression are V V 102 V P 2g and y2 k 0 0 2g where AS ky 1 28 Where H is the exit loss is the velocity inside the culvert barrel v is the velocity in the downstream channel and g is gravity In HY 8 we need to use the first form of the equation Ho 1 0 9 to compute the exit loss 2g and the corresponding outlet control depth The only additional value required between this equation and the previous equation is the velocity in the downstream channel We already compute the downstream channel velocity in HY 8 so we can just use this computed velocity with the Borda Carnot equation to compute the modified exit loss Modified Exit Loss Option To access this equation in HY 8 use Exit Loss combo box in the Macros toolbar in HY 8 This combo box will have two options Exit Loss Standard Method and 2 Exit Loss USU Method If the Standard Method is selected HY 8 will use the current method for computing exit losses If the USU Method is selected HY 8 will use
97. ons Limitations Inlet and Profile Limitations Entrance limitations Since HY 8 is not primarily a water surface profile computation program but is a culvert analysis tool it assumes a pooled condition at the entrance to the culvert Vena contracta assumptions In some cases a vena contracta drawdown of the water surface profile could occur in a culvert barrel since the culvert has the potential to act as a sluice gate at the entrance This drawdown at the entrance is sometimes called a vena contracta The vena contracta is not yet computed for S2 curves but is computed for horizontal if certain conditions exist on horizontal or adversely sloped culverts A coefficient that is generalized for circular and box culverts is used to compute the location and depth of the vena contracta for all culvert shapes Brink depth For culverts with tailwater elevations below the outlet invert of the culvert water flowing out of the culvert would theoretically pass through a brink depth instead of through critical depth In this case HY 8 uses critical depth to determine the final culvert depth and velocity rather than the brink depth Culvert cross section HY 8 assumes the culvert cross section shape size and material does not change in the barrel except in the case of broken back runout sections where you can change the material and Manning s roughness in the runout lower culvert section Hydraulic Jump Computations Hydraulic jump c
98. ors Cmsmemoe Image HY8imagel9 jpg Source http www xmswiki com xms index php title File HY 8image19 jpg License unknown Contributors Eshaw
99. proach and tailwater channels Pool depth under the nappe Depth of flow at the tow of the nappe or the beginning of the hydraulic jump Tailwater depth sequent to y2 L Distance from the headwall to the point where the surface of the upper nappe strikes the stilling basin floor L Distance from the upstream face of the floor blocks to the end of the stilling basin L L Stilling basin length distance from the upstream face of the floor blocks to the end of the stilling basin 100 6 3 2 Stilling Basin Stilling Basins The four types of Stilling Basins External Energy Dissipators available in the program USBR Type III Stilling Basin USBR Type IV Stilling Basin St Anthony Falls SAP Stilling Basin The maximum width of an efficient USBR type stilling basin is limited by the width that a jet of water would flare naturally on the basin foreslope The user is given the maximum flare value and is prompted to enter a basin width smaller than this value If a SAF basin is used the basin width is set equal to the culvert width and the user is prompted to choose either a rectangular or flared basin depending on site conditions Stilling Basins resemble the following illustration 3Fr MIN Variables from the figure Wo width of the channel Width of the basin Culvert outlet depth sy c Depth entering the basin dE m Conjugate depth S ir Slope of the c
100. rs the face section no longer controls and may be used in analysis and construction Detailed information pertaining to side tapered inlets can be found in FHWA Publication HDS 5 bundled with the HY 8 program and accessed from the Help menu Culvert 34 Side Tapered Face Section Plan Slope Tapered A slope tapered inlet is designed to increase the culvert performance by providing a depression and a more efficient control section at the throat designated to represent the location of the culvert where a constant size begins see drawing below Slope tapered dimensions are entered as follows Face Width Width of enlarged face section denoted Wf in the drawing below Side Taper 4 1 to 6 1 _ 1 Slope of walls of tapered transition Value that is input should be the number of units of wall length for every 1 unit of flare Depression Slope 2 1 to 3 1 1 Slope between the entrance and throat invert shown as St in the drawing below Throat Depression Depression of inlet control section below stream bed Measured from stream bed to throat invert Mitered Face Y N Face of culvert cut to conform to embankment slope Crest Length Length of the upstream paved crest at the stream bed This length is only used when the culvert face is mitered If the selected face width and crest width in the case of a mitered face is not wide enough the face or crest section will produce a hi
101. ructure External Energy Dissipators are available in the program Colorado State University CSU Rigid Boundary Basin Riprap Basin and Apron Contra Costa Basin Hook Basin USBR Type VI Impact Basin Colorado State University CSU Rigid Boundary Basin Colorado State University CSU Rigid Boundary Basin No input variables are required for this calculation however one design is selected by the user possible designs for CSU Rigid Boundary Basins are calculated for the given culvert and flow Designs which do not dissipate sufficient energy are discarded The criteria of the remaining designs are numbered and displayed one at a time Designs are calculated and displayed in order of increasing width increasing number of element rows and increasing element height As a result smaller less expensive designs are presented first The following figures show a Colorado State University CSU Rigid Boundary Basin Colorado State University CSU Rigid Boundary Basin 106 Culvert Outlet Variables from the figure W Culvert width at culvert outlet 0 w Element width which is equal to element spacing h Roughness element height Culvert Outlet 1 Variables from the figure V Velocity at the culvert outlet V Sas Approach velocity at two culvert widths downstream of the culvert outlet V Exit velocity Just downstream of the last row of roughness elements E
102. s Cmsmemoe Jcreer Exit Loss Options Source http www xmswiki com xms index php oldid 65753 Contributors Cmsmemoe Hydraulic Jump Calculations Source http www xmswiki com xms index php oldid 65754 Contributors Cmsmemoe EJones Jcreer Tables and Plots Source http www xmswiki com xms index php oldid 65755 Contributors Cmsmemoe Jcreer Crossing Summary Source http www xmswiki com xms index php oldid 65782 Contributors Cmsmemoe Jcreer Culvert Summary Source http www xmswiki com xms index php oldid 65783 Contributors Cmsmemoe Jcreer Water Surface Profiles Source http www xmswiki com xms index php oldid 65758 Contributors Cmsmemoe Jcreer Tapered Inlet Source http www xmswiki com xms index php oldid 65759 Contributors Cmsmemoe Jcreer Customized Source http www xmswiki com xms index php oldid 65760 Contributors Cmsmemoe Jcreer Controlling Plot Display Options Source http www xmswiki com xms index php oldid 65761 Contributors Cmsmemoe Jcreer Article Sources and Contributors 116 Energy Dissipators Source http www xmswiki com xms index php oldid 65745 Contributors Cmsmemoe Jcreer Scour Hole Geometry Source http www xmswiki com xms index php oldid 65763 Contributors Cmsmemoe Jcreer Increased Resistance in Box Culverts Source http www xmswiki com xms index php oldid 65764 Contributors Cmsmemoe Jcreer Increased Resistance in Circular Culverts Source http www xmswiki com xms index php
103. s X Q SPAN SOR RISE 3 SR SR IC C D E F X X X X X SR SO RISE 3 Headwater elevation IHD IH if no Depression 4 For Depression CREST headwater is checked THROAT CONTROL TAPERED INLET 1 X Q SPAN SQR RISE 3 2 HT RISE 1295033 3789944 0437778 4 26329E 03 1 06358E 04 X X X X FACE CONTROL SIDE TAPERED INLET 1 ZZ Q SQOR RISE 3 2 Calculate UNSUBMERGED HF 56 RISE ZZ 66667 3 Calculate SUBMERGED A For bevels 0378 ZZ ZZ 86 RISE IF HF1 RISE THEN HF HF3 IF HF1 lt RISE THEN HF HF IF HF1 gt THEN HF HF1 B For other edges HF2 0446 ZZ ZZ 84 RISE IF HF1 gt RISE THEN HF HF2 IF HF1 lt RISE THEN HF HF1 IF HF gt HF2 THEN HF1 FACE CONTROL FOR SLOPE TAPERED INLET 1 ZZ Q BF SQR RISE 3 2 Calculate UNSUBMERGED 1 5 RISE ZZ 66667 A For bevels 0378 ZZ ZZ 7 RISE IF 1 gt RISE THEN HF IF HFI lt RISE THEN HF IF HFI gt THEN HF B For other edges HF2 0446 ZZ ZZ 64 RISE IF 1 gt RISE THEN HF HF2 IF HFI lt RISE THEN HF 1 IF gt HF2 THEN HF Outlet Control Computations 66 CREST CONTROL 1 HC 2 5 Q CW 66667 OUTLET CONTROL PROCEDURES THAT PRODUCE AN INLET CONTROL PROFILE STEP Compute critical depth
104. s 2 3 4 6 and 7 are all outlet control flow types and are shown in the figure below The various flow type properties may be found in HY 8 by selecting the Flow Types button from the Culvert Summary Table and are shown below OUTLET CONTROL UNSUBMERGED INLET SUBMERGED INLET Flow Type 6 amp 7 Flow Type 4 Outlet Control Computations 63 Outlet Control Computations The logic for determining flow type due to outlet control is shown in the figure below This flowchart uses the following terms HJ Check for Hydraulic Jumps Full flow Check if the culvert is flowing full TWH Depth of the tailwater from the invert of the tailwater channel at the culvert outlet twOutletDepth Depth of the tailwater from the invert of the culvert at the culvert outlet If the culvert is buried this value is taken from the top of the embedment material IH Inlet control headwater depth measured at the inlet invert of the culvert OH Outlet control headwater depth measured at the inlet invert of the culvert RISE Height of the culvert If the culvert is buried this value is taken from the top of the embedment material Inlet Depth The depth computed at the entrance to the culvert using the direct step profile computation method Critical The critical depth in the culvert Normal The normal depth in the culvert Inlet control means that the amount of water the culvert barrel can carry is limited by the culvert entrance Flow pass
105. section Inlet Configurations You can select from the following inlet configurations which are available according to the selected culvert shape The following inlet conditions are available see drawing but may not apply to all shapes or materials Projecting Grooved end with headwall 0 05 X 0 07D e Grooved end projecting 0 05 X 0 07D Square edge with headwall Beveled Mitered to conform with fill slope Headwall The user can select only one inlet condition for each culvert Detailed explanations of these inlet conditions can be found in FHWA Publication HDS No 5 2001 bundled with the program This configuration results in the end of the culvert barrel projecting out of the embankment Projecting Grooved Pipe with The grooved pipe is for concrete culverts and decreases the loss through the culvert entrance Headwalls Grooved Pipe This option is for concrete pipe culverts Projecting Square Edge with Square edge with headwall is an entrance condition where the culvert entrance is flush with the Headwalls headwall Inlet Configurations 39 Beveled Edge with Beveled edges is a tapered inlet edge that decreases head loss as flow enters the culvert barrel Headwalls A mitered entrance is when the culvert barrel is cut so it is flush with the embankment slope Mitered Wingwalls Wingwalls are used when the culvert is shorter than the emba
106. sis is done with all culverts in the crossing and roadway overtopping as considerations BALANCE This means that when you view the performance table or plot for a given culvert within the crossing you are seeing the performance within the context of any other culverts and overtopping of the roadway for the crossing and not just as an isolated culvert as was the case with SINGLE in older versions of HY 8 If there is only a single culvert and the roadway is high enough that overtopping does not occur the performance table of HY 8 version 7 0 would match older versions Differences from DOS HY 8 Front View HY 8 version 7 0 contains an option for displaying the front view elevations of the culvert and roadway at the crossing Hydraulic computations in version 7 0 like older versions are not a function of the lateral placement of culverts within a crossing Only the elevation relationship to the roadway and other culverts is important However if you wish to view this relationship in the front view you will be prompted to enter the lateral stationing of the culverts While irregular shaped roadway sections in HY 8 have always prompted for lateral stations and elevations the constant elevation option only prompted for a length In order to allow for the possibility of defining actual stationing along a roadway HY 8 now includes a beginning station as well as the length for constant roadway profiles The default is zero and can be left as zer
107. ss Options Hydraulic Jump Calculations 5 3 Tables and Plots Tables and Plots Crossing Summary 27 27 28 29 29 31 32 33 35 38 39 40 41 41 41 42 43 44 44 44 45 46 46 53 54 62 62 67 68 77 77 77 Culvert Summary Water Surface Profiles Tapered Inlet Customized Controlling Plot Display Options 6 Energy Dissipation Energy Dissipators 6 1 Scour Hole Geometry Scour Hole Geometry 6 2 Internal Energy Dissipators Increased Resistance in Box Culverts Increased Resistance in Circular Culverts Tumbling Flow in Box Culverts Tumbling Flow in Circular Culverts USBR Type IX Baffled Apron 6 3 External Dissipators 6 3 1 Drop Structures Drop Structures Box Inlet Drop Structure Straight Drop Structure 6 3 2 Stilling Basin Stilling Basins USBR Type III Stilling Basin USBR Type IV Stilling Basin Saint Anthony Falls SAF Stilling Basin 6 3 3 Streambed level Structures Streambed Level Structures Colorado State University CSU Rigid Boundary Basin Riprap Basin and Apron Contra Costa Basin Hook Basin USBR Type VI Impact Basin 78 79 80 81 82 86 86 88 88 89 89 90 91 92 94 95 96 96 96 98 100 100 101 102 103 105 105 105 108 109 110 114 References Article Sources and Contributors Image Sources Licenses and Contributors 115 117 1 Introduction Introduction HY 8 Versions 3 1 4 1 and 6 1 were
108. ssipators and their limitations as follows Chapter Dissipator Type Froude Numbe H Fr Allowable Debri UI Tailwater TW Silt Sand Boulders Floating 4 Flow transitions na H H H Desirable 5 Scour hole na H H H Desirable 6 Hydraulic jump 21 H H H Required 7 Tumbling flow gt 1 M L L Not needed Increased resistence us M L L 7 USSBR Type baffled apron lt 1 L L Not needed 7 Broken back culvert 21 M L T Desirable 7 Outlet weir 2to7 M L M Not needed 7 Outlet drop weir 3 5 to6 M L M Not needed 8 USBR Type II stilling basin 4 5 to 17 M L M Required 8 USBR Type IV stilling basin 2 5 to 4 5 M L M Required 8 SAF stilling basin 1 7to 17 M L M Required 9 CSU rigid boundary basin 3 M L M Not needed 9 Contra Costa basin 3 H M M lt 0 5D Energy Dissipators 87 1 2 3 4 5 6 7 8 9 Hook basin 1 8 to 3 Not needed 9 USBR Type VI impact basin Desirable 10 Riprap basin 3 Not needed 10 Ri 6 na Desirable iprap apron N Straight drop structurel lt l Required H Box inlet drop structurels a Required 12 USACE stilling well na Desirable At release point from culvert or channel Debris notes N none L low M moderate H heavy Bed slope must be in the range 4 lt s lt 25 Check headwater for outlet control Discharge Q lt 1
109. t Coefficient Changes in HY 8 7 3 and Higher In HY 8 7 3 and later versions of HY 8 several significant changes were made to the coefficients used in HY 8 A summary of the changes to the HY 8 coefficients in this version follows Changes to Shapes Using Polynomial Coefficients Changed the slope correction coefficient SR used for all the mitered inlet configurations to the recommended 0 7 Changes to Box Culverts Changed the 1 5 1 Bevel Wingwall inlet configuration from HY 8 Equation 6 to equation 2 For HY 8 Equations 2 3 and 6 added 0 01 to the A Coefficient in the shape database to account for the fact that the equations were derived using a 296 slope a 296 slope was used to derive the polynomial equations meaning 0 5 0 02 was subtracted from each of the polynomial curves and needed to be added back into the equations before correcting for slopes Changes to Shapes using A 1 to A 10 Interpolation Coefficients Added the slope correction term SR Slope to the interpolation equations in the code and added 0 01 to the interpolation coefficients for thin square and bevel inlets Subtracted 0 01 for the mitered inlet Added the SR coefficients All 0 5 except for mitered which 0 7 to the coefficient database and the documentation on this page Table 1 Polynomial Coefficients Circular HY 8 Inlet Configuration KE SR A BS C DIP EE F Equation 1 Thin Edge Projecting 0 9 0 0 187321 0 56771 0 156544
110. t Elevation Roadway Surface Top Width The roadway elevation can be either a constant or vary with station initial roadway station may be defined by the user or left at the default of 0 0 The stationing is used to position culverts along the length of the roadway profile when choosing the Front View option The roadway surface may be paved or gravel or an overtopping discharge coefficient in the weir equation may be entered The user may select a paved roadway surface or a gravel roadway surface from which the program uses a default weir coefficient value If input discharge coefficient is selected the user will enter a discharge coefficient between 2 5 and 3 095 The values entered for the crest length and top width of the roadway have no effect on the hydraulic computations unless overtopping occurs Roadway Profile 20 Roadway Profile Roadway Profile There are two options available when defining the roadway profile constant elevation and irregular With the constant roadway elevation option selected the user is prompted to enter values for the crest length and elevation of the roadway shown in the figure below While not necessary for culvert hydraulic calculations the beginning station of the roadway is also entered the default is 0 0 and does not need to be changed if you do not know the station or do not wish to enter it By defining the beginning station culverts can be located laterally and displayed in
111. ter pool or channel and roadway characteristics The input properties define the crossing and culvert The data defining each culvert are entered in the input parameters widow This window is accessed from the File menu or from Project Explorer window by right clicking on the culvert or crossing and selecting Culvert Crossing Data from the list The user may also select the culvert properties icon from the tool bar From the Culvert Crossing Data window the site culvert tailwater discharge and roadway data are all entered HY8 HY8 Project 2 3 7 Analyze Crossing Crossing Notes Add Culvert Delete Duplicate Rename Culvert Crossing Data 12 Culvert Crossing Data Window of the parameters necessary to define crossing and culvert information can be defined from the Culvert Crossing Data Window as shown below Crossing Data IRRTEST Run Analysis 13 Run Analysis Run Analysis After defining the culvert and crossing data the culvert hydraulics are analyzed including balancing flow through multiple culverts and over the roadway Viewing the analysis of a crossing can be done by right clicking on the desired crossing in the Project Explorer window and selecting Analyze Crossing as seen in the figure below The Analyze Crossing feature can also be accessed for the currently selected crossing from the Culvert Crossing Data Window the Culvert
112. th beveled edge 1 1 iii Beveled Edge 1 5 1 1 Notes a Use HY8 Equation Number 7 b HDS5 Chart Number 3 B c Equation for Circular pipe culvert with beveled edge 1 5 1 iv Thin Edge Projecting 1 Notes a Use HY8 Equation Number 1 b HDS5 Chart Number 2 3 c Equation for Corrugated Metal pipe culvert Thin edge projecting v Mitered to Conform to Slope 1 Notes a Use HY8 Equation Number 2 b HDS5 Chart Number 2 2 c Equation for Corrugated Metal pipe culvert Mitered to conform to slope Concrete Open Bottom Arch HY 8 Version 7 3 and later has coefficients for computing inlet control depths for concrete open bottom arch commonly called Con Span culverts Geometric Characteristics Con Span culverts have unique geometric configurations and several sizes and shapes are available The exact coordinates used in HY 8 to compute areas and other geometric cross section parameters are available in this document Since the culverts can be made to accommodate any required rise for a given span HY 8 contains culvert geometry in 3 inch increments of rise Inlet Control Polynomial Coefficients The polynomial coefficients used by HY 8 were derived from a study and document prepared by Don Chase at the University of Dayton Ohio 1999 Dr Chase determined a different set of coefficients for culverts with different span to rise ratios Con Span culverts with a 4 1 span to rise ratio performed better resulted in a lower headwater
113. the USU Borda Carnot equation to compute exit losses Hydraulic Jump Calculations 68 Hydraulic Jump Calculations Determining if a Hydraulic Jump Exists and its Location A hydraulic jump is created in a rapidly varied flow situation where supercritical flow rapidly becomes subcritical flow As the flow changes energy is lost to turbulence However momentum is conserved across the jump The two depths of flow just prior to and after a hydraulic jump are called sequent depths To determine if a hydraulic jump exists HY 8 determines the supercritical and subcritical water surface profiles that form within the culvert using a direct step profile computation At each location along the two profiles HY 8 computes the sequent depths of the supercritical profile and compares these sequent depths to the subcritical profile s computed depth While HY 8 computes the supercritical profile a hydraulic jump forms if either of the following two conditions occurs 1 the sequent depth profile intersects the subcritical profile or 2 the Froude number is reduced to approximately 1 7 in a decelerating flow environment M3 S3 H3 or A3 flow See the section in FHWA s HEC 14 on broken back culverts 7 4 If the outlet is submerged HY 8 uses the energy equation to determine the hydraulic grade line Once the hydraulic grade line falls below the crown of the culvert HY 8 uses the direct step method to determine the remainder of the profi
114. tion is available for circular or box culverts and is shown below side tapered inlet is designed to increase culvert performance by providing a more efficient inlet control section A side tapered circular inlet has an enlarged elliptical face section with a transition taper to the circular culvert barrel The side tapered dimensions are entered as follows Face Width Width of enlarged face section denoted Wf in the drawing below Side Taper 4 1 to 6 1 1 Flare of walls of circular transition Value that is input should be the number of units of wall length for every 1 unit of flare Face Height Shown as Hf in the drawing below can be no smaller than the barrel height and no larger than 1 1 times the barrel height A side tapered rectangular inlet has an enlarged rectangular face section with transition taper to the culvert barrel The side tapered dimensions are entered as follows Face Width width of enlarged face section Side Taper 4 1 to 6 1 1 flare of walls of rectangular transition Value that is input should be the number of units of wall length for every 1 unit of flare If the selected face width is not wide enough the face section will produce a higher headwater elevation than the culvert throat as shown in the Improved Inlet Table The user must continue to increase the face width and run the analysis until the headwater depth ceases to change with increasing face width Once this occu
115. trapezoidal and triangular When selecting a channel shape the input window adjusts to display only those parameters required for the defined shape When defining a channel shape the following channel properties are required for analysis Bottom Width Width of channel at downstream section shown in drawing below Side Slope H V 1 This item applies only for trapezoidal and triangular channels The user defines the ratio of Horizontal Vertical by entering the number of horizontal units for one unit of vertical change Channel Slope Slope of channel in m m or ft ft If a zero slope is entered an error message appears upon exiting the input data window The user must enter a slope greater than zero before the crossing may be analyzed Manning s n User defined MANNING S roughness coefficient for the channel Channel Invert Elevation User must enter elevation Program will show actual barrel 1 outlet invert elevation TW Invert Elevation Slope _ HW Channel Shape 22 Channel Invert Elevation Rating Curve The rating curve option represents flow rate versus tailwater elevation for the downstream channel When the Enter Rating Curve option is selected the user is prompted to define 11 increasing flow and elevation values as shown below When using this option a channel invert elevation generally the same as the downstream invert of the culvert is required so t
116. ulic computer models in her research and determined several improvements some of which have just recently been implemented in HY 8 in Culvert Hydraulics Comparison of Current Computer Models by Elizabeth Anne Thiele 2007 Nathan Lowe studied hydraulic jumps in various closed conduit configurations to make possible comprehensive hydraulic jump calculations in Theoretical Determination of Subcritical Sequent Depths for Complete and Incomplete Hydraulic Jumps in Closed Conduits of Any Shape 2 by Nathan John Lowe 2008 Nathan s equations were used to determine locations and lengths of hydraulic jumps in HY 8 7 3 Introduction HY 8 automates the design methods described in HDS No 5 Hydraulic Design of Highway Culverts FHWA NHI 12 029 and in HEC No 14 FHWA NHI 06 086 Version 6 1 is the last version of the MS DOS program that was distributed Hydrologic calculations are available in the Watershed Modeling System WMS and in the FHWA Hydraulic Toolbox The software has been structured to be self contained and this help file functions as the program s user s manual This facilitates its use by roadway design squads However the knowledgeable hydraulic engineer will also find the software package useful because it contains advanced features This help file provides necessary instructions and clarifications References 1 http contentdm lib byu edu cdm singleitem collection ETD id 1004 rec 1 2 http contentdm lib byu edu cdm
117. us Y Equivalent depth The next two figures show a hook basin with a uniform uniform trapezoidal channel End Sill View Plan View 1 Profile View Ws B Wp Ti h Hook Basin 113 Variables from the figure Wo Outlet width Wi Width at first hooks W Distance between first hooks row A W lateral spacing between A and B hook e W n Width of hooks W Width of slot in end sill W approximately channel width B e h Height of end sill e h Height to top of end sill e h Height to top of warped wingwall Oy Equivalent depth Li Distance to first hooks L Distance to second hooks row B L Basin length Variables from the figure Angle of radius r radius e h height to center of radius h Height to point h Height to top of radius USBR Type VI Impact Basin 114 USBR Type VI Impact Basin USBR Type VI Impact Basin No input variables are required for this calculation The following figures show a USBR Type VI impact basin x 203 mm max 8 in 1 1 4 DIA MINI LI i 4 152 mm 6 1 3 Fillet irr 6 in BEDDING SECTION STILLING BASIN DESIGN ALTERNATE END SILL Variables from the figure Required basin width e W m Geometry design variable e h 1 through h Geometry design variable t through t i Geometry design variable
118. wn below from the original HY 8 help file Inlet Control Computations UNSUBMERGED INLET SUBMERGED INLET sawam a Flow Type 1 Flow Type 5 Inlet Control Logic DETERMINE APPLICABLE INLET CONTROL EQUATION 1 IF circle or box with IMPROVED INLETS then use INLET equations 2 For Straight previously called conventional INLETS A If Qis lt Q at 5D then assume LOW FLOW INLET CONTROL i calculate CRITICAL DEPTH DCO ii calculate Section Properties iii VH Q 2 64 4 iv IH DCO LMULT 1 KELOW VH VHCOEF IF no Depression THEN IH For Depression HF IH and check head on CREST B If Q gt Q at 5D but lt Q at 3D then use INLET REGRESSION EQUATIONS C If Q gt Q at 3D then assume HIGH FLOW INLET CONTROL i IH Q CDAHD 5 RISE ii IF no Depression THEN IHI IH For Depression HF IH and check head on CREST Inlet Control Computations 51 INLET REGRESSION EQUATIONS Q between Q at 5D and Q at 3D 1l CIRCULAR A See Straight inlet equations B SIDE TAPERED ELLIPTICAL TRANSITION THROAT CONTROL ZZ Q SQR RISE 5 Y LOG ZZ 2 30258 i IF n lt 015 THEN SMOOTH PIPE IMPROVRD INLET ii If n 22 015 then ROUGH PIPE IMPROVED INLET iii Calculate THROAT CONTROL iv Calculate FACE CONTROL v IF Depression Then CW CWF calculate CREST control C SIDE TAPERED RECTANGULAR TRANSITION or SLOPE TAPERED i Calculate THROAT CONTROL ii Calculate
119. y input variable required for this calculation is the following Basin Width Variables from the figure height of the chute blocks e h width of the chute blocks e h ges Height of the end sill W j Space between chute blocks W height of the end sill L Length of the bottom of the basin Saint Anthony Falls SAF Stilling Basin 103 Saint Anthony Falls SAF Stilling Basin The input variables required for this calculation is the following Shape Flared or Rectangular Sidewall Flare This will only apply if the basin has a flared shape The following figure shows a Saint Anthony Falls stilling basin JT Ls RECTANGULAR BASIN HALF PLAN FLARED BASIN HALF PLAN 0 90 E 45 PREFERRED e Variables from the figure Ww Basin width W jc Basin width at the baffle row B Basin width at the sill Y i height of the chute blocks L Length of the basin Z basin flare Saint Anthony Falls SAF Stilling Basin 104 SIDE WALL VARIES x CHUTE BLOCK VARIES FLOOR OR BAFFLE BLOCKS L m Wm s 0 07 Yz CUT OFF WALL Variables from the figure Yi height of the chute blocks Y Conjugate height Y height of the chute blocks Em elevation of basin floor 105 6 3 3 Streambed level Structures Streambed Level Structures The five types of At Stream Bed St
120. ynomial Generation Inlet control means that flow within the culvert barrel is supercritical and not capable of transmitting losses upstream The determination of the headwater depth therefore is not found using the energy equation but is the result of many scaled model tests In HDS 5 Appendix A submerged and unsubmerged equations developed by the National Bureau of Standards from the scaled model tests were originally used to determine headwater depths These equations required four coefficients K M c and Y Unfortunately once plotted the transition zone between unsubmerged and submerged flow was not well defined For the purposes of the HY 8 program a fifth degree polynomial curve was fitted through the three regions of flow unsubmerged transition and submerged see equation below Fifth degree polynomial coefficients were obtained for all combinations of culvert shape and inlet configurations sa 85 585 Polynomial Coefficients 54 Polynomial Coefficients Overview For circular box elliptical pipe arch concrete open bottom arch commonly called CON SPAN and South Dakota Concrete Box culverts polynomial coefficients found in Tables 1 6 are utilized in the inlet control headwater computations Other culvert shapes use Table 7 which shows the HW D points A 1 through A 10 for interpolation Each row of coefficients represents different inlet configurations for different culvert shapes Note Abou

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