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drainage requirement in pavements

1. Open previously Saved Generated DRIP data file Look in 5 Dip e P Ee el example drp al Ix File name Files of type Drip data drp Cancel Zi Figure 2 The file open dialog box Save generated DRIP data file zi xi Save in Drip e eaea File name Save as type IIs Cancel 4 Figure 3 File save dialog box File Export Summary Creates a summary of the active DRIP project file The format of this file is Hypertext Markup Language HTML and it can be viewed using any Web browser spreadsheet or word processing program Since DRIP analyses are modular in nature the summaries provided are also divided into subsections Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Layer and Edge Drain A summary for a particular subsection is output only if data has been entered for that analysis or that analysis has been completed If no data has been entered only the primary header of that analysis module is provided TT 10 To export the project summary to an HTML file the following steps need to be followed 1 Select the File Export Summary command from the File menu A Create DRIP summary file dialog box similar to the one shown in Figure 4 pops up prompting the user to enter to enter a file name under which the DRIP project file summary will be saved 2 Save the summary file to an appropriate directory on the computer by specifying a file
2. Water Loss dialog box is closed by pressing the OK button the selected value appears in the Water Loss edit box on the Sieve Analysis property page m Type of fines Filler Silt C Clay Amount of Fines E 65 Cancel Gravel Jeo Figure 17 Water Loss dialog box Inflow The next recommended step in a drainage analysis is to calculate the pavement infiltration due to rainfall and meltwater where applicable This calculation is handled in the Inflow property page The user can perform this calculation using the Infiltration Ratio method or the Crack Infiltration method by selecting the appropriate radio buttons By default the program uses the latter method Adding meltwater to the inflow calculation can be enabled or disabled by means of the Include Meltwater check box The Inflow property page configured for the Infiltration Ratio method is shown in Figure 18 In the Infiltration Method category box the user can indicate whether the surface is TT 26 fi Drainage Requirements in Pavements Unsaved File File Options Help M Road Geometry x z z wW S Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain S ft ft a PR Infiltration Ratio Method T Include meltwater in inflow calculations LR ft Crack Infiltration Method Eater m Mateias _ Infiltration Method HA Heave in day Base Defined eT Portlan
3. Discharge Rate Approach option list Two other methods are given to compute the maximum outlet spacing Permeable Base and Time to Drain Since the time to drain method was not used for designing the permeable base we will not examine this approach For computing the outlet spacing L based on the Permeable Base approach select the appropriate radio button from the Discharge Rate Approach options Our previously computed base discharge q4 of 44 81 ft day ft appears automatically This results in a maximum outlet spacing of 281 ft Thus the permeable base discharge result is the critical value so the user should specify an outlet spacing of 281 ft TT 51 The final edgedrain design screen is shown in Figure 44 Note the updated summary on the left side of the screen shown in the figure A printed output summary can be obtained by clicking on File Print Summary menu option E Drainage Requirements in Pavements Unsaved File File Options Help Hoad Geometry x 5 Woa Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain Analysis Type 2 0 0283 N aE ypical roughness coefficients for under drain ZRA Y Pipe T Smooth Pipe n 0 012 m Mateias s pomo eee poa M Corrugated Pipe n 0 024 Base Defined Subgrade Defined D f Inflow Qi 042 daz Discharge Rate Approach gt able pase In 02 Ganz Pavement Infiltration Q permed am T t
4. Print Summary option The format of exported summary file is HTML and it can be viewed using any Web browser spreadsheet or word processing program The steps involved in exporting and printing project summaries have already been outlined in the section dealing with DRIP menus Since DRIP analyses are modular in nature the summaries provided are also divided into subsections Roadway Geometry Sieve Analysis Inflow Permeable Base Separator and Edgedrain A summary for a particular subsection is TT 42 output only if data has been entered for that analysis or that analysis has been completed If no data has been entered only the primary header of that analysis module is provided 5 0 EXAMPLE PROBLEMS This section contains sample exercises that acquaint the user with the operation of DRIP These examples also illustrate how to perform hydraulic design using DRIP As noted in PART 3 Chapter 1 drainage analysis and design should be considered as a first step in structural design The DRIP program is also useful to determine air voids and effective grain sizes for a given gradation which are important materials inputs to the 2002 Design Guide software The examples presented below will also explain how to perform these calculations Example Problem Number 1 Given A pavement section consists of two 12 ft lanes of 9 in thick PCC pavement with 10 ft AC shoulders on each side with a uniform cross slope not crowned and the width of t
5. 50 Drainage AASHTO Guide 85 Saturation Pavement Rehabilation Manual Quality of Drainage Time to Drain Good Poor T Month Figure 27 Permeable Base time to drain property page TT 34 Once the user is satisfied that the value provided for base thickness H is sufficient to handle any possible variations in the design parameters the capacity of the permeable base ga can be computed by clicking the calculator icon located to the left of the corresponding label The Permeable Base property page configured for the time to drain method is shown in Figure 27 As with the depth of flow method values would already have been supplied for many of the parameters from previous screens There are calculator icon buttons beside the labels for permeability k and effective porosity ne that the user can click to call the Sieve Analysis property page Estimated values for these parameters can be determined based on aggregate gradation input in that page However it is recommended that these values be obtained instead through laboratory testing Once the values for k Ne SR Lr H and percent drainage U are supplied the user can click the calculator icon to determine the time required to drain t By default the parameter t is estimated using the Barber and Sawyer equation Alternatively if the Casagrande and Shannon Method is the preferred method the corresponding radio button must be first selected and the calculator butt
6. D so 1 31e 003 in rye sp m Permeable Base i D 25 4 00e 003 in H 1 ft D sonaren 5 poe U lt Aggregate Separator 15 mane ih hr 7 12 5 OOS l D separant 25 pee qq 77 405 Odin 4 93e 003 50 50 ad 15 in r Edge Drain Pipe D 0 0118 L in separator a8 x Di 200 D oos i 85 in Lo 7652 f Q 178102 a Figure 30 Separator aggregate separator layer property page After DRIP determines whether the design passes the necessary separator layer criteria left clicking the graph icon located in the Criteria category box will generate a plot which graphically summarizes the design performed For an aggregate separator layer design TT 37 this plot contains the gradation plots of the subgrade the base course and the separator layer In addition the numerical values of the design criteria are also plotted and are represented using red triangles The right pointing triangles denote the lower limit while the left pointing triangles denote the upper limit of the desired gradation band for the separator layer A sample plot generated from the Separator property page is shown in Figure 31 Ifa chosen separator layer passes all the required design criteria its gradation should fall within this desired band as illustrated in Figure 31 As with the plots generated on the Sieve Analysis property page either a Power 0 45 or a logarithmic scale can be employed for the horizontal axis for this plot Aggregate Separator Laye
7. The net effect in this case is that the plot will take up 50 of the page Print Page Setup l i x Percent gt Top margin fio Bottom margin eo Left margin fi 0 Right margin 0 Cancel Figure 8 Print page setup Edit Menu The Edit menu currently has a single menu command which is Copy The Copy command allows the user to copy the current plot onto the Windows clipboard and to directly paste that plot into any applications that accept Windows bitmaps View Menu The View menu commands allow the user to change the basic look of the DripPlot application View Toolbar toggles whether the shortcut toolbar is displayed beneath the DripPlot menu The View Status Bar toggles whether the status bar is displayed along TT 16 the bottom of the DripPlot Window The status bar gives a short description of each menu item and displays whether the Num lock Cap lock and Scroll lock keys are set Window Menu The Window menu is designed to arrange and navigate among the plots generated by DRIP At the bottom of this menu is a list of plot files currently open Any plot can be brought to the foreground by selecting that plot name from among the menu options Window New Window Creates a new plot with current DRIP data Used to recreate a modified plot Window Cascade Arranges plots one on top of the other in a manner similar to that of a deck of playing cards Each plot is slightly offset from the one directl
8. The percent open area should be equal or greater than 4 percent as noted close to the bottom right of the screen TT 55 Step 6 Finally click on the balance icon on the right hand side of the screen to see if the chosen geotextile passes all the necessary criteria All the criteria checks generate a Pass rating for the selected geotextile The final screen for the geotextile separator layer design is shown in Figure 47 Ae Drainage Requirements in Pavements examples drp File Options Help E S R Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain SR 0 0283 H m Analysis Type Criteria LR 33 94 ft C Aggregate Separator Soil Retention Y Steady State Dynamic Flow ech TY Geotestile Separator Permeability T Normal Critical Conditions Materials C No Separator Clogging Normal Critical Conditions Base Defined Subgrade Defined Subgrade p Criteria LC tor Geotextil 31 0 eparator Geotextile Pop 1 x E Inflow kes l ig AOS 3D gt Pass qi 0 42001 Ean Be Ca n73 Am 232001 fran Dis 587004 n Cu gt 3 Been Permeable Base D 95 01498 in H 0 33333 T Kseparator 71 D aads gt Pass U 50 x r Geotextile Separator AOS 752002 in 2 t 05 hr l Recommendation 04 44 811 Oan k 10 0 fted The percent open area of the geotextile Woven min should be equal to or greater than 4 Edge Drain Pipe C Non woven D 4 Fa L fico ftd Lo 21 ft Bl Une
9. This is because the data plotted in the sensitivity charts is precomputed for realistic ranges of the independent value These ranges are hardcoded into the program and cannot be changed However the minimum X value can be changed to any level to increase the resolution of the plotted graphs DRIP Property Pages DRIP has been arranged to flow smoothly from beginning to end of the design process This has been accomplished by breaking the entire drainage design process into six sub processes and developing a tabbed property page for each Roadway Geometry Sieve Analysis Inflow with the Meltwater sub screen Permeable Base design Separator layer design and Edgedrain design The user can access any of these property pages by selecting the appropriate tab along the top of the DRIP client window The layout of the property pages on the DRIP client window see Figure 1 suggests a logical left to right flow of drainage design which is recommended However the program has the flexibility to allow the user to start at any point within the program and to use only a few of the program components including the use of only a single property page While the property pages can be utilized in a stand alone manner they are somewhat interdependent in that the inputs on one page can be taken from the calculations on another The interdependencies of the DRIP property pages are shown in Figure 11 Sieve Analysis E Base required Gradatio
10. User s Guide for Drainage Requirements in Pavements DRIP 2 0 Microcomputer Program FHWA Contract No DTFH61 00 F 00199 July 2002 TT 70 qa or Qp 45o APPENDIX TT 1 STANDARDIZED NOMENCLATURE ROADWAY GEOMETRY Item English Longitudinal slope ft ft Cross slope ft ft Resultant slope ft ft Resultant length of flow through base ft Width of permeable base ft Angle between roadway cross slope and resultant slope PAVEMENT INFILTRATION Rate of pavement infiltration YI Infiltration ratio Rainfall rate in hr Crack infiltration rate ft d ft Number of longitudinal joints or cracks Length of contributing transverse joints or cracks ft Spacing of contributing transverse joints or cracks ft Width of permeable base ft Pavement permeability ft day Number of contributing traffic lanes PERMEABLE BASE DISCHARGE Permeable base discharge rate ft d ft OUTLET SPACING Pipe flow ft day Longitudinal length of contributing roadway ft Width of contributing roadway ft TT 71 m m m m m m m s m mm hr m am m sec m s m a4 gt oro Brae Ka Oxx SOILS Item Coefficient of Uniformity Effective size Soil particle size Dry unit weight of material Unit weight of water Bulk specific gravity Porosity Effective porosity Volume of voids Volume of water Total volume Water loss Percent drained Percent saturation DARCY S LAW Flow capacity of base Coefficient of permeability Hydraul
11. example drp E _2 x File Options Help Hoad Geometry Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain W 125 ft SR 00M4 fet r Analysis Type Criteria ie me tt C Aggregate Separator Soil Retention gt Steady State Dynamic Flow N Geotextile Separator Permeability Normal Critical Conditions p Materials T No Separator Clogging Normal Critical Conditions Base Defined L Subgrade Defined m Subgrade p Criteria Separator Geotextile 75 0 Pong 10 00 fed Inflow ko AOS 3D gt Pass qi 0702 am Bc fe 1 16 2 r L Gin Oia D 55004 n Cu gt 3 Se ae Base S D 25 4 00e 003 in A x San 2 Ksubgrade gt Fail U 50 gt Geotextile Separate Kes 7 26002 i t 24 br AOS r2 Ly Recommendation 0 774 dn s 10 0 fled The porosity of the geotestile should da C Woven Kee be greater than 50 r Edge Drain Pipe Non woven Da 2 Kop 1 006002 wa Lo 765 2 ft PEE L 390005 in Q 178102 u Figure 32 Separator geotextile separator property page opening size AOS of the geotextile and the minimum allowable permeability kmin of the geotextile Typically at this stage in design a geotextile that satisfies the AOS and Kinin requirements is selected and its actual permeability is entered in the ksep edit box The calculator icon for tng Will then become enabled and the maximum allowable thickness of the geotextile for permitt
12. or activated an active calculator icon is blue in color By positioning the screen cursor over an active calculator icon and clicking the left mouse button the value is calculated and displayed in the edit box Thus edit boxes are used as the primary means of both input and output An alternative method for navigating to the calculator icon is to press the Tab key until the desired button has the focus i e until a faint dotted line appears around the button text Once the button has the focus hitting the space bar selects the button Even when it is desirable to let the system calculate a value for a specific parameter the user always has the option to type a value into the edit box To permit this feature the program diligently checks for data conflicts to maintain consistency within a design and integrity of the program Thus typing a value for a parameter that should be calculated may cause conflicting values for other parameters to be erased TT 20 A list of parameters used in this program is included at the end of this appendix as Appendix UU 1 Standardized Nomenclature Roadway Geometry Although DRIP operates in a modular manner and the design process can be performed in any order it is suggested that the user access the Roadway Geometry property page first The Roadway Geometry property page screen is shown in Figure 12 On the upper right side of the screen are two graphics representing the available options
13. summary will be saved 2 The user can choose to either save the summary information to be printed to a file by clicking the Save button recommended or can opt not to save it by pressing TT 11 Cancel button Note the summary files are automatically saved with an extension of htm 3 After the file Save or Cancel operations are performed the program automatically opens the Print dialog box shown in Figure 5 from where the user can select the printer to send the output to the printer choices displayed will obviously be a function of the user s local environment Note that the output will be printed using default format settings If the formatting of the default output layout needs to be changed the user will need to open the saved summary file using standard word processing or spreadsheet programs to edit the file Printer Name HP L asetet IIISi PS Properties Status Default printer Ready Type HP Lasenet IIISi PostScript Where Www w2 HPLIIIISi Comment T Print to file m Print range Copies All Number of copies 1 Pages from fi to fi E Selection EM lf el T Collate r Print frames E As lad outon screen Onu the selected frame G Allframes malvidually T Print all linked documents T Print table of links Cancel Figure 5 The Print dialog box File Exit Ends the current DRIP session If the user selects this option or clicks on the Close ic
14. 0083 Tn Q 12594 du Figure 47 Geotextile separator layer design Edgedrain Design Step 1 Click on Edgedrain tab to access the property page Click on the Geocomposite radio button Step 2 Select the row for the Hydraway edgedrain from the table on the right side The value of C 1333 ft day is automatically returned to the appropriate edit box Step 3 Type in a value of 12 in for the height of flow zone D and 4 in for the diameter of the pipe Do Step 4 Use the time to drain method for outlet pipe spacing by clicking on the Time to Drain radio button on the Discharge Rate Approach category box All the necessary time to drain inputs should already appear in the respective variable edit boxes from the earlier computation on the Permeable Base screen Step 5 Click the calculator icon to compute Q and L The program returns Q 1691 1 and L 59 4 ft The final screen for the geocomposite edgedrain design is shown in Figure 48 TT 56 Drainage Requirements in Pavements examples drp Rasa R Akwadrain Hitek 20 Hitek 40 Neca 6200 epn pe o Figure 48 Design of geocomposite edgedrain Example Problem Number 3 Given The gradations of a permeable base and a proposed aggregate separator layer to be used in a project are given in Table 2 Also given is the gradation of the subgrade soil at the project location Determine Determine the need to place a separator layer between the permeable ba
15. 0200 ft ft iar G s y Subgrade Geotextile 2 2 2 P E installati x S Se 2 5 ES S N lt installation t hr qa a n r Edge Drain Pipe D in Lo ft Q 1d Figure 37 Computation of roadway geometry The values entered and computed in this screen will be stored and carried forward to other screens where they are needed The completed Inflow screen is shown in Figure 38 The computed inflow value is updated in the summary page Meltwater Computation Step 1 Step 2 Step 3 Activate the Meltwater sub screen in the Inflow property page by clicking on the Include Meltwater in the inflow calculations checkbox The heave rate Heave for the clayey silt subgrade soil can be determined by clicking on the calculator button located to the left of the variable This action calls up the heave rate table The heave rate table shows that the value for clayey silt soil is 0 51 in day This value can either be entered manually in the edit box on the Meltwater sub screen or entered automatically by selecting the row corresponding to clayey silt soil type Note For materials with large heave rates the mid point values may be entered Enter the given values for the subgrade permeability kup 1 ft day unit weight of the pavement surface 162 lb ft the unit weight of the base material above the subgrade 100 lb ft the thickness of pavement surface H 9 in and the thic
16. 12 Low to medium Gw cm 3 7 0 12 0 18 Medium to high GM 7 10 0 12 0 18 High to medium Gw cc 42 42 0 10 0 10 Medium GM GC 15 15 0 20 0 20 High GC 15 30 0 10 0 20 Medium to high SP 1 2 0 03 003 Very low sw 2 2 012 012 Medium SPM h15 2 0 01 0 06 Negligible to low 5 9 SW SM 2 0 06 0 24 Low to high SM 5 0 24 0 35 High to very high SM 9 22 0 22 0 35 Very high to high SMSC 95 35 0 20 028 High SC 35 35 0 20 028 High ML OL 23 33 0 04 0 55 Low to very high ML 33 45 055 098 very high Silt and organic silt ML 45 65 0 98 0 98 Very high ML cL 60 75 0 51 0 51 Very high cL 38 65 0 28 039 Highto very high Lean cla cL 65 65 0 20 020 High Lean cla CL OL 30 70 016 016 High Fat clay CH 60 60 003 003 Verylow Figure 21 Heave determination dialog box TT 29 range of heave values will automatically appear in the edit box In addition to heave rate determination the user should also provide a value of subgrade permeability ksu An estimate of the subgrade permeability can be directly entered based on laboratory test data or can be determined based on sieve data Selecting the calculator icon next to the ksu edit box returns the user to the Sieve Analysis property page from where this parameter can be estimated The other parameter required to estimate inflow due to meltwater is load of the pavement structure o which inc
17. Contract No DTFH61 00 F 00199 The enhanced version 2 0 was finalized in 2000 TT 1 DRIP Capabilities The salient features of DRIP are described below Each of these features can be executed independently from within the program Roadway Geometry Calculations Using this program feature the user can compute the length and slope of the true drainage path based on the longitudinal and transverse grade of the roadway as well as the width of the underlying base material The user can perform these calculations for the two common roadway cross sections commonly encountered crowned and superelevated uniform slope sections Sieve Analysis Calculations The effective grain sizes D total and effective porosities coefficient of uniformity and gradation and coefficient of permeability can be computed for any user entered gradation using this program feature Plots of the gradations on semi log and FHWA power 45 templates can also be obtained from this program screen Inflow Calculations The amount of moisture infiltrating the pavement structure from rainfall and meltwater can be computed using this program option The surface infiltration calculations can be performed using two different approaches the Infiltration Ratio approach and the Crack Infiltration approach Meltwater computations can be performed for a variety of soil types and pavement cross section depths Permeable Base Design The program offers two permeable
18. Expert Mode is available When DRIP is running in the Expert Mode all warning and TT 8 informational dialog boxes are suppressed allowing the user to enter potentially incorrect data or to edit a dependent variable Only experienced users should attempt to use DRIP in the Expert Mode The Expert or Normal mode selection is made under the Options Mode menu item When first run DRIP defaults to the Normal mode with all the warning and informational dialog boxes activated DRIP Menus Menus in DRIP are used to control file handling help and program options All menu items can be accessed from any of the tabbed property pages File Menu Options Including Print Summary The File menu controls file handling printing and summary output When DRIP is first started the program opens into a new DRIP project or session file This new DRIP file is empty except for a few default input parameters At this time the user should either open a previously generated DRIP project file by using the File Open menu command or name the newly created DRIP project file by using the File Save menu command File New Creates a new DRIP project file clearing all user input data from the currently active project file There can only be one active project file for each DRIP client window Creating a new DRIP project file with the File New command within an active DRIP client will close the currently active DRIP file A newly created DRIP project file
19. NE To aterial Librar a Bound Bound Base r Materials Remove Base Defined Subgrade Defined Base C Subgade Seperatorlayer V Include aggregate seperator 5 0 5 0 Separator Aggregate r Gradation Analysis _ Porosity Inflow Py 5 0 sy Unit weight 150 bet 20 0 20 0 di 0702 dam ps q 3 Dip 5 19e 003 in HU Specific Gravity 2 95 116 paste Ahas ae 300 300 Dh eee f mal Pi ble Base aoe j pls r Fermeat 85 0 85 0 Bie gaa 5 H 1 ft 15 0 1967 m r Effective Porosity x 100 0 100 0 Water Loss Method U 50 LC RT 0 0367 G ater Loss Metho t 211 hr Water Content Method 04 0774 00 d Da 00487 in mae 5 00 x p Edge Drain Pipe Dep 00554 n Bey n ones 4 i i Q Dgs 0 0743 n Lo 7652 f Q 178102 d Cu 1068 Ce 487 ml k nnn fd L T L Figure 14 Sieve Analysis property page When all of the sieve data has been entered the user can select the calculator button located in the Gradation Analysis box to perform a grain size distribution analysis If the entered gradation data is not consistent DRIP warns the user by changing the font color of the value in question to red For example if the user entered 50 passing the 4 Sieve and 100 passing the 8 the number 50 0 would be highlighted in red since it is physically impossible to have such a gradation TT 23 DRIP allows the user to enter
20. Resultant Slope mim L 10m g 3 e 5 m 3 sim 2 k 900 miday Figure 61 Minimum base thickness versus resultant slope TT 67 Resultant Length Figure 62 shows the effect of resultant length of drainage path The relationship is linear meaning that if the resultant length is doubled the required base thickness is doubled This is logical since twice the amount of water will need to be contained in the base course a 7 7 7 7 om H a O Pe a ee s d 0 7 a e TT H O 7 ee ee ee ee ee ee A yi ot f a ee a ee ee eee ee Resultant Length m 0 02 g 3 e 5 m 3 sim 2 k 900 miday Figure 62 Minimum base thickness versus resultant length of drainage path Infiltration Rate Figure 63 shows that the required base thickness is sensitive to the rate of infiltration with the required thickness increasing as q increases as would be expected While there is large sensitivity to changes in qi when the value is very small the sensitivity becomes more linear after H reaches a more reasonable value greater than 0 15 m TT 68 0 5 0 45 0 4 0 35 _ 03 0 25 0 2 0 15 0 1 0 05 0 9 75e 7 1 95e 6 2925e6 39e6 4875e6 5 85e 6 6 825e 6 7 8e 6 8 775e 6 9 75e6 Inflow m 3 s m 2 L 10 m 5 0 02 k 900 mid Figure 63 Minimum base thickness versus infiltration rate TT 69 REFERENCES 1 Mallela J G E Larson T Wyatt J P Hall and W Barker
21. appear here Under the separator layer property page select the No Separator option by clicking on the radio button Then check the permeable base subgrade interface by clicking on the balance symbol under the Criteria category box The program indicates that the uniformity criterion has not been satisfied This implies that a separator layer is required Figure 49 displays the program screen generated from this calculation TT 58 Drainage Requirements in Pavements example 2 drp Ta Hl Figure 49 Final program screen for the No Separator option Drainage Requirements in Pavements example 2 drp E SS a Figure 50 Final program screen for the Aggregate Separator option TT 59 Step 6 Now choose the Aggregate Separator radio button Check the criteria again by clicking on the balance icon This results in the program generating a Pass rating for all the criteria Therefore the chosen separator layer is adequate The final program screen for this computation is shown in Figure 50 Step 7 A plot showing the gradations of the subgrade permeable base and the separator layer can be obtained by clicking on the graph icon next to the balance icon On this plot the upper and lower bounds of the gradation band within which the proposed separator layer has to fit to be considered acceptable also appear These bounds are basically a graphical representation of the design criteria The plot can be generated on a FHWA pow
22. base design options depth of flow and time to drain These methods allow the user to design an open graded base that can handle the inflow entering the pavement structure Separator Layer Design Using this program option the user can design two types of separator layers geotextile and aggregate separator layers Based on the gradations of the proposed permeable base and the subgrade under consideration the program also verifies whether a separation layer is required at all TT 2 Edgedrain Design Two types of edgedrains can be designed using this program option geocomposite of fin drains and pipe edgedrains The program calculates the edgedrain capacity and the outlet spacing required New Features in DRIP Version 2 0 DRIP 2 0 retains the capabilities of the earlier version of the program but makes the execution more efficient and incorporates all the new features explained in the previous section DRIP 2 0 incorporates several significant advancements in user interface and capabilities e Win32 support Fully compatible with Windows 95 98 NT e Normal and Expert modes Normal mode warns users of potential errors during input and offers suggestions on proper program use Expert mode suppresses these warnings allowing experienced users of program the ability to edit data more quickly without continually acknowledging warning screens e Tabbed property pages The individual data input and analysis screens employed in
23. based on the inputs provided by the user This icon is activated turns colorful only when all the necessary inputs for a given calculation are configured For example in Figure 1 the parameter W can be calculated by pressing the calculator icon only after the inputs b and c have been configured In certain instances pressing the calculator icon opens a dialog box e g heave rate determination in the Inflow property page or transports the user to an appropriate property page where inputs to calculate the parameter under question should be configured e g the Dx calculation in the TT 7 Separator property page Calculator icons appear on every property page JHL Graph icon Generates appropriate graphs for the property page in which it is located and opens DripPlot to display them The graph icons appear on Sieve Analysis Permeable Base and Separator property pages aF ad Balance icon Checks whether the design criteria for the aggregate and geotextile separator layers are satisfied on the Separator property page DRIP Help Context sensitive help can be accessed for any program variable by right clicking the mouse button while the cursor is on top of that variable A small help box will appear superimposed above the DRIP dialog box giving a short description of the variable in question Hyperlinking in DRIP Most of the property pages in DRIP are interconnected As a consequence an input on a certain page may be an output
24. both the sieve and hydrometer analysis data when determining grain size distribution It is important to include the sieve size where less than 10 passes so that the program can properly determine Dj It is also important to include the sieve where at least 85 of the material is passing so Dgs can be properly determined When the user selects the calculator button in the Gradation Analysis box a grain size distribution analysis is performed to calculate effective sizes at different percentages D10 D12 Dis D30 Dan Doo D85 percent passing the 200 sieve Cy coefficient off uniformity and C coefficient of curvature or gradation After the calculator button is selected in the Gradation Analysis category box the Gradation plot button becomes active Selecting this button calls DripPlot and displays a grain size distribution plot The program defaults to a Power 0 45 horizontal scale but the user may change this to a semi log scale using the Options Plot Scale menu command On the main DRIP window the gradation of the AASHTO 57 material is plotted in Figure 15 on a Power 0 45 chart as an example Grain size Distribution Base Course 30 80 70 60 50 40 Percent Passing 30 20 200 50 16 4 1 2 3 4 S 1 1 2 Sieve Size AASHTO 57 Figure 15 Example output of a value input sieve analysis In addition to entering sieve data DRIP allows the user to select materials from the
25. in Figure 30 The right side of the design screen displays particle size criteria to prevent intermixing of layers The left side of the screen allows the user to input particle size values e g Dio Dis Dso and Dss for the permeable base subgrade and separator layers These values should already be present if a complete gradation analysis has been completed for all the materials on the Sieve Analysis property page If the particle size values are missing for any given layer the user should go to the Sieve Analysis property page to compute these values This can be done either by clicking the calculator button adjacent to the layer in question or by clicking the Sieve Analysis tab on the DRIP client window When all the required D values are configured the balance and graph icons on the right side of the screen turn blue in color By clicking on the balance icon the aggregate separator layer design criteria can be checked E Drainage Requirements in Pavements example drp E E 215 File Options Help r Road Geometry W 125 f Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain SR 00141 fet Analysis Type LR 1768 f Aggregate Separator T C Geotestile Separator p Materials C No Separator Base Defined r Base Course Criteria Subgrade Defined Separator Aggregate D 15 8 13e 003 in Gal L E D 0 0487 in r Inflow 50 Des lt ST di 228 fam Subaorade dm 1 15 Hdt
26. is unnamed It is suggested that the newly created DRIP project file be named using the Fiel Save menu command While each DRIP client window allows only a single DRIP project file to be active it is possible to have several DRIP client windows running on one computer File Open Opens a previously saved DRIP project file identified by a drp extension The current active DRIP project file is closed without saving The File Open dialog box is of the MS Windows Explorer style allowing the user to rename copy and paste files within it Figure 2 illustrates the File Open dialog box File Save Saves the current active DRIP project When this option is selected a dialog box such as the one shown in Figure 3 opens prompting the user to save the current DRIP project The user may choose to save a DRIP project with a file extension other than the default drp extension However this is not recommended since files saved with an alternative extension will not appear automatically in the dialog box when the File Open menu command is executed If the current active DRIP project has been previously saved the File Save menu command will not open the Save generated DRIP data file dialog box but instead will overwrite the previously saved DRIP project file File Save As Same as File Save menu command except that this command will always open the Save generated DRIP data file dialog box shown in Figure 3 TT 9
27. modified and enhanced by the ERES Division of ARA under FHWA Contract No DTFH61 00 F 00199 Mr Robert Baumgardner and Mr Bing Wong of the FHWA supplied the technical control for the project The ERES principal investigator was Dr Jim Hall and Mr Gregg Larson implemented the program modifications Mr Jagannath Mallela of ARA ERES served as the project manager Under this contract DRIP Version 2 0 and a revised user s guide were developed Incorporation of DRIP into the design guide was done at ARA ERES under the guidance of Mr Jagannath Mallela TT 2 APPENDIX TT DRAINAGE REQUIREMENT IN PAVEMENTS DRIP MICROCOMPUTER PROGRAM USER S GUIDE 1 0 INTRODUCTION Brief History of DRIP Development Moisture related pavement distresses have long been recognized as a primary contributor to premature failures and accelerated pavement deterioration The Federal Highway Administration FHWA provides design guidance for drainage in its manual numbered FHWA TS 80 224 Highway Subdrainage Design Under a study known as Demonstration Project No 87 or simply Demo 87 the FHWA Pavement Division developed a comprehensive effort to provide design guidance for handling water that infiltrated into the pavement structure from the surface That study resulted in the production of the Participant Notebook for Demonstration Project No 87 Engineers needed a concise and user friendly microcomputer program that replicates the subsurface drainage
28. name Note that the summary files are automatically saved with an extension of htm Save in a NewProject 12 IZ c Save as type DRIP summary htm lt Cancel Z Figure 4 Dialog box to save project summary information Once the summary information is saved to a file it is automatically displayed on the computer screen using the default HTML browser application The information can be printed directly from this application using standard print commands Alternatively the summary information file can also be opened with any standard word processing or spreadsheet programs that reads HTML documents e g Microsoft Word or Microsoft Excel The advantage of using a word processing or spreadsheet application is that they enable the user to custom format the information contained in the file Further tabular data is stored using HTML tables and therefore can be utilized directly by a spreadsheet applications such as Microsoft Excel to create custom plots of DRIP data This capability is in addition to the intrinsic plotting package DripPlot provided with DRIP File Print Summary Prints the output summary information The following steps need to be followed to print the summary information 1 Select the File Print Summary command from the file menu A Create DRIP summary file dialog box similar to the one shown in Figure 4 pops up prompting the user to enter a file name under which the DRIP project file
29. resident Material Library When a material is selected from the Material Library all of the sieve and property data saved for that material will be entered in the appropriate edit boxes overwriting the data already present The user can also save custom gradation data to the Material Library along with other material property information such as unit weight porosity and effective porosity by following these simple steps TT 24 1 Select the type of layer base subgrade or separator for which data will be entered This can be done by selecting the appropriate radio button on the Sieve Analysis property page 2 Select either the Range or Value data entry form and enter the desired gradation data 3 Click on the Add button in the Material Library box Assuming that the input data does not contain inconsistencies an Add Gradation to Library dialog box appears see Figure 16 If there is an error in gradation data entry the inconsistent data appears in red colored font and will need to be corrected 4 Enter a text based file descriptor that will be also used as a file name This file name will have the extension sgd attached to it and will be saved in the GradFiles folder in the DRIP directory Avoid using any DOS file control characters when describing the material Add Gradation to Library 3 2 x Gradation Library Name aa ooo Note An ascii file with a sad file extension is created using this libra
30. 5 Time to Drain hrs Base Thickness m Barber Sawyer Casagrande Shannon Figure 59 Time to drain versus base thickness using Casagrande Shannon and Barber Sawyer methods here can be generated by the clicking on the graph icon after the required minimum base thickness Hmin has been computed Permeability In Figure 60 it can be seen that the effect of the coefficient of permeability is inversely proportional to the required minimum base thickness As the permeability of the material increases the base will drain faster and thus a thinner permeable base can be used As the permeability increases the required minimum base thickness decreases at a decreasing rate Resultant Slope As shown in Figure 61 the design procedure is sensitive to slope with the required base thickness decreasing as the slope increases As is the case for the time to drain the flatter the slope the slower the water will drain and thus a thicker base is required to contain all the water The depth required continues to drop over the entire range of slopes presented As was stated previously the base will drain even if the slope is flat however it is questionable practice to apply the design procedure to flat slopes TT 66 D 200 400 600 800 1000 1200 1400 1600 1800 2000 Permeability m d L 10 m S 0 02 g 3 e 005 m 3 sim 2 Figure 60 Minimum base thickness versus coefficient of permeability
31. Copy No Guide for Mechanistic Empirical Design OF NEW AND REHABILITATED PAVEMENT STRUCTURES FINAL DOCUMENT APPENDIX TT DRAINAGE REQUIREMENT IN PAVEMENTS DRIP MICROCOMPUTER PROGRAM USER S GUIDE NCHRP Prepared for National Cooperative Highway Research Program Transportation Research Board National Research Council Submitted by ARA Inc ERES Division 505 West University Avenue Champaign Illinois 61820 February 2004 Foreword The contents of this appendix were adapted from the FHWA DRIP User s Guide 1 and are provided in support of PART 3 Chapter 1 and Appendix SS of the Design Guide DRIP can be used to perform the necessary calculations for the hydraulic design of permeable bases and edgedrains as well as for the design of aggregate and geotextile separator layers This program is available in the Design Guide software under the Tools Additional Programs menu Acknowledgements Applied Research Associates Inc developed the original version of the microcomputer program titled Drainage Requirements in Pavements DRIP Version 1 0 under a contract from the FHWA contract No DTFH61 95 C 00008 Mr Robert Baumgardner of the FHWA supplied technical control for the project The ARA principal investigator was Dr Walter Barker and Mr Tim Wyatt led the development of the computer program Dr Jim Hall served as program manager The program was delivered to the FHWA in September 1997 This program was
32. DRIP Version 1 0 have been updated improved and are now displayed using a property page format This new format allows a more intuitive navigation through the various program screens Each property page can be accessed by means of the tabs displayed continually along the top of the DRIP client area e Analysis type selection The DRIP program allows the user to select the type of roadway geometry inflow calculation method permeable base analysis type separator layer analysis type and edgedrain type The selections available under each of these categories are usually located in the upper left corner of the respective property page in the form of radio buttons By making the appropriate selection the user can customize the analysis performed on each property page For example to perform time to drain design of permeable bases the user should select the Time to Drain radio button on the Permeable Base property page The program then configures the page to display appropriate inputs and outputs for this analysis e Hyper linked input data fields In the DRIP program certain variables appear on multiple property pages The hyper linking feature is aimed at preventing the novice user from inadvertently entering different values for the same DRIP variable on different property pages By clicking the left mouse button on a hyper linked variable identified by an underline beneath it the program transports the user to a property page where this v
33. a roadway with crown in the centerline and a roadway that slopes in the same direction on both sides of the centerline Indicate which geometry best fits the design situation by clicking the appropriate radio button The equation for width of drainage path W reflects the geometry selection as will the profile graphic in the middle right side of the screen To calculate W the user must first provide values for the parameters b the width of pavement surface and c the distance from the pavement shoulder to the edge of the permeable base by entering this data in the appropriate edit box When values have been supplied for both parameters the calculator icon beside the parameter W will become activated Clicking on this icon will cause the value for W to be calculated using the equation shown In the same manner when values are provided for longitudinal slope S and cross slope Sx the calculator icons for resultant slope Sp and resultant length of drainage path Lp are activated The calculator icons become activated whenever all data values that are required to evaluate the respective equations are available The user always has the option to type in a value for the parameter rather than use the equation to calculate it However doing so may cause the program to erase values of other parameters to avoid inconsistencies For example assume that the user has provided values of 9 3 m and 1 2 m for parameters b and c respectively Selecting the cal
34. an extrapolated passing 200 value of 0 5 is displayed Select the Silt radio button for the type of fines This produces a Water Loss value of 76 for gravel Select this value with a cursor and click OK to transport this value to the Sieve Analysis screen Step 5 Click on the calculator icon adjacent to the effective porosity ne on the Sieve Analysis screen to compute this value The program computes n 0 163 The final screen for computation of the permeable base material properties is shown in Figure 45 Permeable Base Design Time to Drain Step 1 Click on the Permeable Base tab to access the corresponding property page Select the Time to Drain radio button The values for the design inputs ne k Sp Lr and H should already be present from the analyses done as part of the previous example and this session so far Step 2 The time to drain factor t can be determined based on 50 percent drained or the 85 percent saturation criteria The former is the more conservative for permeable bases so it will be used Enter U 50 TT 53 Drainage Requirements in Pavements examples drp AASHTO 57 CC Sa 9 d Geperstorlaver J L g po Pp Pp i po Pp po Pp po po Pp i Pp i p 25 S sO i 25 a 1000 Pp i Pp Pp i pe Figure 45 Performing particle size analysis of the permeable base Step 5 Click on the calculator icon adjacent to the variable r to compute it A value of 0 55 hr is returned if the Ba
35. ande and Shannon Method if Poor 1 Month Lo 281 0 ft ite ps hr ay Very Poor Does Not Drain Q 125937 td Figure 46 Time to drain computations for permeable base Separator Layer Design Step 1 Click on Separator tab to access the property page Click on the Geotextile Separator radio button Step 2 For conservatism click the Dynamic Flow radio button for Soil Retention Criteria Also click the Critical radio button for permeability criteria Step 3 The P200 Ksup Cu Dis and Dss should be retained from the previous screen If these values are not present click on the calculator icon in the Subgrade category box enter the Georgia Red Clay gradation compute the particle sizes D x and Cy and enter the given ksu value Then click on the Separator Layer tab to return to the separator layer property page Step 4 Once all the necessary computations are made the separator property page should have the following values for the variables P209 31 Kap 1 ft day Cu 211 73 and Dis 5 88e 04 in Dss 0 1498 in Click on the Woven Geotextile radio button in the Geotextile Separator category box Click on the calculator icon to compute AOS 0 0785 in and k 10 ft day Step 5 Suppose a woven geotextile with AOS of 1 6 in and a permeability of 100 ft day can be found type in kan 100 ft day Click on the calculator icon to compute tmax 0 069 in for the geotextile This is the maximum thickness of the geotextile
36. arator layer screen is shown in Figure 43 Note that the summary page on the right side of the DRIP screen shown in the figure now states that the base and subgrade materials have been defined TT 50 IE Drainage Requirements in Pavements Unsaved File File Options Help gt Road Geometry Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain We 24 ft SR 0 0283 fft Analysis Type LR 3394 ft C Aggregate Separator m Materials Base Defined Subgrade Defined Base Course Criteria Separator None Di 5 053 in E any D 05484 in r Inflow 30 I hea ZSD gt Pass H 134 an Subgrade S Gm 992 iu ae Desa e gt Pass bk EL Permeable Base Ds 01498 in H 0 33333 ft IG N E hr qd 44811 baste ad r Edge Drain Pipe Figure 43 Checking separation criteria Edgedrain Design Step 1 Select the Edgedrain tab Step 2 Select the Pipe Edgedrain radio button Click the Corrugated checkbox and a value Of Nmanning 0 024 is displayed Type in a value of D 4 in Step 3 The calculator icon is enabled for calculating the pipe capacity Q The computed pipe capacity should read 12 594 ft day Step 4 Click on the L button to compute the outlet spacing This gives an L value of 391 6 ft However this value is based on the default selection of the Pavement Infiltration method for the pavement discharge rate see under
37. arator radio button to evaluate the need for a separator layer Click on the calculator icon next to the Base Course variable This shifts the user to the Sieve Analysis property page The permeable base is made up of the AASHTO 57 material The gradation for this material is already in the sieve analysis library To initialize this gradation to the program click on the drop down material library list box and select AASHTO 57 Click on the calculator icon to determine the particle sizes for Dzs and Dso Select the Separator Layer tab again The values of D 5 0 2529 in and Dso 0 5484 in appear for the Base Course Click on the calculator icon next the Subgrade variable to compute the subgrade particle sizes The user is returned to the Sieve Analysis property page again and the Subgrade radio button is automatically activated Select the Value radio button and enter the subgrade gradation in the grid on the left hand side of the property page Compute the Ds9 and Dss by clicking on the particle size calculator icon Return to the separator layer property page by selecting the Separator tab The values of Dsp 0 0253 in and Dgs 0 1498 in are returned for the subgrade On the Sieve Analysis property page check the filtration and uniformity criteria at the subgrade base interface by clicking on the balance icon on the right hand side Both the criteria generate a Pass rating which implies that no separator layer is required The completed sep
38. are completed on this page the respective values are displayed on the left side of the main DRIP client window This screen can be exited by clicking on another tabbed property page Inflow Computation Crack Infiltration Method Step1 Select the Inflow tab to access the corresponding property page Click on the Crack Infiltration Method radio button since this method was required to be chosen to estimate inflow Step 2 Retain the default values of 2 4 ft day feet for J and 0 for pavement permeability ky Also retain the values for W and W that have been automatically carried forward from the calculations performed on the Roadway Geometry page Step 3 Enter the number of longitudinal cracks Ne as 3 N the number of contributing lanes 1 2 1 3 Enter the given transverse spacing of contributing transverse joints C 20 ft TT 44 Step 4 IE Drainage Requirements in Pavements Unsaved File File Options Help Click the calculator icon to compute inflow qi This should yield a value of 0 42 ft day ft gt Road Geomet ics ry S Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain SR 0 0283 ftit b 2a ft inne tf ee sg l 9 c fo ft p Materials C Geometry A eome Base Undefined Geometry B Subgrade Undefined Separator None W b AE 2c Inflow gaw fas ft qi tam aos din fed reo n r Permeable Base Sx 0
39. ariable should most logically be configured e Improved graphics The graphics that illustrate drainage input variables have been improved e Summary screen A linked summary list is now present on the left side of the DRIP client window This list allows the user to get an update on the status of the current DRIP session TT 3 e Context sensitive help Right clicking on any variable in the DRIP program displays a short description of that variable e Improved online help The complete DRIP user s manual is now available and searchable online and from within the program e HTML analysis summary A formatted report on the inputs used and outputs calculated in the current DRIP session is available using the File Export Summary command This information contained in this file is in standard HTML format and can be read and edited using standard browser applications word processing programs or spreadsheet software e Print analysis summary A well formatted printed report displaying the inputs used and outputs calculated in the current DRIP session is available using the File Print Summary command e Improved gradation library The importing and saving of sieve gradation analysis has been improved The program allows descriptive file naming to save input gradations for future use e Additional sieve sizes Particle sizes determined from hydrometer tests can now by used by the DRIP model e Improved graphing Graphing of grain size distr
40. ay and the vertical stress on the top of the subgrade o is 200 lb ft Enter these values in the appropriate edit boxes and click on the graph icon to determine 4m Moulton s meltwater chart appears on the screen On this chart a horizontal red line marking the entered heave rate of the subgrade 0 1 in day appears In order to compute the meltwater the computer mouse can be used to slide the vertical tick line along the horizontal red line to the location where o is approximately 200 lb ft When the mouse is at the right position the value for qm S should read 0 36 A left click of the mouse button will then produce a value for gm of 3 61 ft day ft This value is transported to the qm edit box on the Inflow property page when the Evaluation of the Meltwater Inflow dialog box is closed While including meltwater is a conservative approach engineering judgment may need to be exercized in adding this value the pavement infiltration from rainfall qj The combined inflow of qi and qm could be unreasonably high in some situations A flowchart illustrating the data flow on the Inflow property page is presented in Figure 23 TT 30 Evaluation of Meltwater Inflow E al x Average Rate of Heave mmvday WS LR A CL aS LL Tm oO foo psf k 100 ft day Heave 2 5 mm day Very High m Meltwater Infiltration qn vk 0 46 High Medium Frost Susceptibility C
41. be used to design either pipe or geocomposite pavement edgedrains In addition a number of other dialog boxes are accessible from within certain property pages For example a dialog box for the estimation of the quantity of meltwater using Moulton s chart is available from the Meltwater property page A number of plots are available from the DRIP property pages including 1 depth of flow and time to drain sensitivity plotting accessible from the Permeable Base property page 2 meltwater inflow plotting accessible from the Inflow property page and 3 aggregate gradation plotting accessible from the Separator layer property page or the Sieve Analysis property page Input and Output DRIP uses standard Windows edit boxes within each property page to display input and output values which allows the user to input a value for any parameter after positioning the screen cursor over the appropriate edit box and clicking the left mouse button The user can then type the input value from the keyboard In many cases however it is desirable to let DRIP calculate the parameter value based on user provided input values for other parameters Calculator icons beside the parameter labels identify cases where the variable should be calculated by the program Calculator icons often are accompanied by an equation that indicates which parameter values must be input When the required input values have been provided the calculator icon will become enabled
42. cale dialog box is shown in Figure 10 TT 17 Titles and Labels E p x Font Size Graph Title Gransee Distibution BaseCouse S me Avis Label Sieve See iz Y Axis Label Percent Passing HZ Cancel Figure 9 Title and Labels dialog box Lines Legends and Scale B Line Color Line Type Line Thickness Legend 1 Barber Sawyer Green Sad E Legend2 sendesh ea orea e ea E E a a a D ent Legend 4 D M z e fi Legend 5 z z j Legend Font Size fio Saing Minimum Value Axis jo Minimum Value Y Axis fo Cancel Maximum Value X Axis fi Maximum Value Y Axis 20 Axis Tick Marks fo Y Anis Tick Marks 3 Figure 10 Lines Legends and Scale dialog box When using the above referenced dialog box keep in mind e Five separate legend entries appear in the box which is the maximum number of individual series that can appear on a single DRIP plot For plots with fewer than five series the additional edit boxes are disabled e The Line Color edit boxes control the color of the plots generated by DRIP The standard line thickness used by a plot generated by DRIP is 2 However different line thicknesses from 0 to 10 types solid dotted dashed and dashed dot and colors can be used to identify different series TT 18 e For the sensitivity plots although the program allows the maximum value for the X axis to be changed to any number the plotted data might not be extend over the entire range
43. culator icon yields a W value of 5 85 m Now proceed to provide values of 0 05 and 0 03 for S and Sy respectively and calculate values of 0 0583 for Sr and 11 37 m for Lr Now manually edit the value of W rounding it up to 6m Doing so erases the value of c because the combination of b and c that are provided cannot result in a W value of 6 m The program also erases the value of Lr because the value of 11 37 m does not reflect the new design parameter that was provided This process of erasing data requires the user to recalculate values that reflect new inputs thereby adding to the integrity of the final design It also prevents the user from mistakenly assuming that values of dependent parameters are still valid A flowchart showing the data flow in the Roadway Geometry property page is presented in Figure 13 TT 21 File Options Help Road Geometry W 125 h SR 0 0141 Vn LR 1768 ft Materials Base Defined Subgrade Defined Separator Aggregate di 0702 arn Gm 116 fam Permeable Base Hi ft U 5 toa hr Ga 0774 94 Q 178102 td Drainage Requirements in Payements example drp Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain 2 wy 56 Ee Le 17 68 Edgedrain pipe Permeable Separator base layer Geotextile Trench Figure 12 Roadway Geometry property page Select Geomet
44. d Cement Concrete l k ath ft d Asphalt Cement Concrete Separator None Kad eal C Jo se5 y E a Inflow Note Appropriate values for C range from 0 5 to 0 67 b lb ft qi 0 702 Oaa Hs ft q ine 1 Year 1 Hour Rainfall FHWA TS 80 224 m C 2Year 1 Hour Rainfall FHWA SA 92 008 H ft m Permeable Base 0 6 7 H t E R a o H H was Note 1 Hour rainfall amounts are recorded in in hr U E o K t hr da Odon q 0 702 tan E dm Hran qi CRF Figure 18 Inflow Infiltration Ratio property page asphalt or concrete by clicking the appropriate radio button The range of acceptable values for infiltration coefficient C is noted below the edit box The user may type an estimate of the value in the edit box or click the x icon to automatically fill the edit box with the midpoint value Changing the surface type will erase any displayed value of C and will require the user to provide a new value The lower portion of the screen allows the user to type in a value for the rainfall rate R which can be approximated from the rainfall map displayed in online help when the calculator icon is pressed By default the program displays the map for a 2 year 1 hour storm which is recommended in FHWA report number FHWA SA 92 008 The user can opt to display instead the map for a 1 year 1 hour storm which is recommended in FHWA TS 80 224 Both maps show R values in units of in hr so if the analysis is
45. d computes andplots the dependent variables The charts are plotted using the DripPlot The DripPlot window appears as soon as the graph icon next to the Hynin variable is clicked and the following sensitivity plots are displayed e Required Base Thickness Hin vs Pavement Inflow d or gi qm e Required Base Thickness Hin vs Base Course Permeability k e Required Base Thickness Hin vs Resultant Slope Sz e Required Base Thickness Hmin vs Resultant Length Lp The user can control the type of plots to be displayed in the DripPlot window using the Options Sensitivity menu command prior to clicking the graph icon An example sensitivity plot of required base thickness versus permeability is shown in Figure 42 Do oo LA Required Base Thickness H ft o 9 9 E m co G LA m Les LD Q o oa 00 1500 2000 2500 3000 3500 4000 4500 5000 Coefficient of Permeability k ftiday L 33 94 ft S 0 0283 q 1 34 tt Sidst 2 Figure 42 Depth of flow sensitivity analysis example H vs k The generated plots can be directly saved as image files jpeg or dib formats using the appropriate options under of the File menu Hard copy outputs can also be generated using the File Print command or using the printer icon on DripPlot TT 49 Separator Layer Design Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Select the Separator Layer tab Select the No Sep
46. design procedures in the Participant s Workbook for Demonstration Project No 87 Also because of the increasing use of the SI unit system there was a need for the program to incorporate both SI and pound inch U S Customary units Under a contract from the FHWA contract No DTFH61 95 C 00008 Applied Research Associates Inc developed the original version of the microcomputer program titled Drainage Requirements in Pavements DRIP Version 1 0 DRIP was finalized in 1997 In 1998 a new National Highway Institute course NHI Course No 131026 titled Pavement Subsurface Drainage Design was developed to further improve the guidance on pavement subsurface drainage design construction and maintenance DRIP Version 1 0 was integrated into this course to perform hydraulic design computations The program has since been used in the industry and has received excellent reviews However several valuable suggestions were made by DRIP users to further improve the program The suggestions mainly pertained to improving design input screen graphics variable plot displays and outputs and the user s manual Certain key drainage calculations and plotting options were also suggested to enhance DRIP s technical capabilities In addition there was a need to upgrade the program to be compatible with the computing environments prevalent today Thus version 1 0 of the program was modified and enhanced by the ERES Division of ARA under FHWA
47. di Permeable Base ies 0 Beparator aver G C Time To Drain eotextile H 0 33333 ft Edgedrain pi if rain pipe U 5 da men dn L g Let iia hr Ga 44811 Part r Edge Drain Pipe D 4 in ga o jas tdd Lo 21 0 ft gl A 281 0 ft Q 125937 fd Figure 44 Pipe edgedrain design and outlet spacing computation Example Problem Number 2 Given The input data are the same as Example Problem No 1 except that a woven geotextile is used for the separator layer and a Hydraway geocomposite edgedrain is present Permeability conditions are critical Determine Calculate the time to drain of the permeable base Design the geotextile separator layer Calculate the outlet spacing for the geocomposite edgedrain Note The roadway geometry and inflow calculations do not have to be performed again TT 52 Solution Sieve Analysis Step 1 Click on the Sieve Analysis tab in the DRIP client window Select the Base radio button The AASHTO 57 gradation configured in the previous example should appear automatically in the grid on the left side of the screen Step 2 Enter the given values for the Unit Weight 130 pcf and Specific Gravity 2 65 of the base Step 3 Compute the porosity n 0 214 by clicking on the calculator icon Step 4 Select the Water Loss Method radio button to compute the effective porosity This selection is justified since AASHTO 57 is a coarse gradation Immediately the Water Loss table pops up On this screen
48. e coefficient of permeability of the base k 3000 ft day Compute the Hmin by clicking on the calculator icon A Hmin value of 0 1437 ft is reported which is lower than the selected permeable base thickness H of 0 3333 ft Therefore the design is satisfied Note If Hmin were much greater than H the designer would make adjustments to the design by changing design variables such as base thickness or permeability If the base thickness H can be revised this parameter must be changed to be at least equal to the Hmin Compute flow capacity of the permeable base qa by clicking on the appropriate calculator button This yields a value of 44 811 ft day ft The flow capacity is estimated from Moulton s chart A completed design screen for the depth of flow design is shown in Figure 41 The values computed here are carried forward to other screens The summary box on the DRIP client window is also updated accordingly TT 47 File Options Help rainage Requirements in Pavements example4 drp Base Defined Subgrade Defined Separator None r Inflow qi 0 42 anz dm 0 05 perder m Permeable Base H 0 33333 ft x hr 44 811 ddn Gr Id m Edge Drain Pipe Eile Options Help rainage Requirements in Pavements example4 drp lc 24 teed Ne g El JV Include meltwater in inflow calculations m Meltwater m Road Geometry 5 A W 24 Roadway Ge
49. e lower bound heave rates are the same as upper bound heave rates indicating that there is very little variability in the data The user may use this table to estimate a heave rate for a given soil type and manually enter it into the Heave edit box or alternatively obtain the value by clicking on the desired row in the table If the latter method is used the midpoint of the selected TT 28 E rainage Requirements in Payements example drp Fie Options Help r Road G tr E Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain W 125 tt SR 004 ftit D EEA JV Include meltwater in inflow calculations LR 1768 f Crack Infiltration Method gt Meltwater Mateias Infiltration Method BE Heave 01 in day Base Defined I 3 fioo Subgrade Defined i Td CS ka Nd Separator Aggregate Ne el ie 120 be Inflow We S n h fs Ka di 228 an Hs f R Am 1 16 daan Wa Dn m H P C m Permeable Base Cs fi ft Ht f PEU RE U 50 kp fo fd BI E i toa hr p da 074 an q 228 dian al dm 8 tam r Edge Drain Pipe D4 in I NG W W wc Lo 752 ft qi ie Q 178102 Aq Figure 20 Inflow calculation with Meltwater included Heave Determination Min Max OK sate aves rag inida in da Cancel GP 012 012 Medium GW S r 0 01 0 04 Negligible to low GW 1 15 0 04 0 14 Low to medium GW 15 4 0 08 0 14 Medium GP GM 2 3 0 04 0
50. e product tested FHWA 1P 90 012 L i TE Geocomposite LR 1768 C Poe r Mateias _ i Hydraway 1195 oo UU Cg FE 5 T z Akwadrain 473 Base Defined Subgrade Defined D fi 0 n D2 2 in Hitek 20 523 Separator None Hitek 40 E l 1820 sail D d D x Miradrain 6000 224 z la S Strip Drain 1000 1246 r Inflow qi 228 Hat Discharge Rate Approach mae Pavement Infiltration 2 e Im 116 Oa Permeable Base L q Ossi C Ti Y d A Wate a Fin Drain m Permeable Base Time To Drain ub H 07 ft U s qd ja 722 deft gt Trench bottom i hr kad dq 4722 ddn eee r Edge Drain Pipe pi 4 Q zs td Lo s11 t Q 3829 00 Figure 35 Edgedrain geocomposite property page A flowchart of the Edgedrain property page depicting the data flow in this screen is shown in Figure 36 TT 41 Pipe Select Geocomposite oS Input Input S D n S Cg D D Calculate Q Select approach to compute qd Calculate No Lo Calculate Lo Q Has solution converged Yes Output Edgedrain Q Lo Figure 36 Flowchart for Edgedrain property page Project Summary The two methods of obtaining analysis reports from DRIP are either to export the project summary using the File Export Summary option or to print it using the File
51. e property page for the time to drain method The sensitivity plots presented here can be generated by the clicking the graph icon after the time to drain parameter t has been computed Porosity In Figure 53 it can be seen that the effect of effective porosity is linear This means that if the effective porosity is doubled the time to drain is doubled This is logical since twice the amount of water will be released from the base course However engineers should not yield to the temptation of reducing the effective porosity to reduce the time to drain It must be remembered that the goal of drainage is to remove as much water as possible from the base course TT 61 K w Time to Drain hrs N Effective Porosity Barber Sawyer U 50 SR 0 02 H 0 2 m LR 10 m k 900 mid Figure 53 Time to drain versus effective porosity Permeability In Figure 54 it can be seen that the effect of the coefficient of permeability is inversely proportional to the time to drain The more permeable the material the faster the base material will drain Also the effect of permeability on the time to drain parameter decreases with increasing permeability Resultant Slope As shown in Figure 55 the design procedure is sensitive to the resultant slope with the time to drain decreasing as the slope increases This is logical the steeper the slope the faster water will drain The
52. employing metric units the user needs to manually convert these values to their metric equivalent When values have been provided for both R and C the calculator icon for inflow qi is activated Clicking the icon will calculate q using the equation shown The Inflow screen for the Crack Infiltration method is shown in Figure 19 When the program begins the crack infiltration rate Jc has a default value of 2 4 ft day ft 0 22 TT 27 Ae Drainage Requirements in Payements example drp g 2 x File Options Help m Road Geometry W 125 ft Roadway Geometry Sieve Analysis Inflow Permeable B ase 5 eparator Fan Drain SR IME Wea t Vinhittaton Rahol Method T Include meltwater in inflow calculations LR 1768 ft Crack Infiltration Method Meltwater Materials m Infiltration Method HAlHeae 015 in day Base Defined Ic 24 3 0 00 Subgrade Defined C IST H Kee ted Separator Aggregate Nc R H fiz 105 Ian We a h fs bt di 228 arte Hs il ft z Wp 10 ft Am 116 Oan ti H ft r Permeable Base Ca il ft o H H H 1 ft gt 5 brb TE S kp fo ftzd u RI o 20a IE hr 04 0 774 Odon q 228 a Ez am DE Hra Edge Drain Pipe D 4 in N W q E G IC k o tee a aly a v Q 178102 du S Figure 19 Inflow Crack Infiltration property page m day m Some other input parameter values may already be filled in when the property pa
53. er 45 chart by selecting Options Plot Scale Power 45 command from the Options menu Alternately selecting Options Plot Scale Semi log command from the Options menu will result in a semi log plot Figure 51 presents a gradation plot for the design example solved above on an FHWA power 45 chart Figure 52 presents a semi log plot of the same example in metric scale for comparison Semi log plots are useful in visualization when the gradations range from very fine to very coarse material However the D values computed in DRIP are based on the power 45 charts 100 T L T T Tra E T gt PEELED oe Ea L An i ia ae 90 1 PEF E H ma Fa 80 if if ne S E a Pe ue a 70 a i we D Aar 5 60 A i a lt s50 D 2 D A 40 30 Pf 20 L i 1 10 LA i 0 Y 4 200 50 6 4 1 2 3 4 1 Sieve Size Base Subgrade Separator gt Lower bound 4 Upper bound Figure 51 Separator layer design shown on an FHWA power 45 plot TT 60 0 002mm 0 020mm 0 075mm 0 425mm 2 36mm 475mm 12 5mm 25mm A A T AAT A A A E AA E A A U HHH L 2 Percent Passing Sieve Size mm Base Subgrade K Lower bound lt 4 Upper bound Separator Figure 52 Separator layer design shown on a semi log plot 6 0 SENSITIVITY ANALYSIS Time to Drain The following plots were developed using the sensitivity plotting functionality of the Permeable Bas
54. fering scales legends titles and so on File Save as Dib File Saves the current plot as a device independent bitmap Saving a file as a Dib allows the user to import this plot into another Windows application The file is saved as it appears on the user s screen including size line color and titles File Save as Jpeg File Save the current plot as a JPEG graphic file Saving a file as a Jpeg allows the user to import this plot into another Windows application The file is saved as it appears on the user s screen including size line color and titles TT 15 File Print This menu command prints the current plot By default the plot is printed in portrait mode with the margins set in File Print Page Setup File Print Preview This command displays how each plot will look when printed File Print Setup Allows the user to select which printer to user as well as edit that printer s properties such as paper source paper size and orientation File Print Page Setup Calls the Print Page Setup dialog box which is shown in Figure 8 The dialog box sets the margins used when printing a DripPlot graph Valid inputs in these boxes range from 0 to 100 and represent the distance from the top and left margins For example a value of 10 for the Top Margin means that the top margin will end 10 from the top of the page A Bottom Margin of 60 means the bottom margin begins 60 from the top of the page
55. ge is first selected if they have been generated by previous inputs and calculations For example if the user calculated W 5 85 m on the Roadway Geometry screen using Geometry A and values of 9 3 m and 1 2 m for b and c respectively then the W edit box will contain the number 5 85 and the edit box for width of pavement Wc will contain the number 4 65 or b 2 Other parameters to be supplied are permeability kp of the pavement surface transverse crack spacing Cs and number of contributing longitudinal cracks Nc Nc is generally equal to one plus the number of contributing traffic lanes When values are provided for all these parameters the calculator icon for qi will be activated allowing the calculation to be performed The user should compare the value calculated here to the value calculated using the Infiltration Ratio method and choose the larger number for the sake of conservatism Along the same conservative vein the user may wish to include meltwater in the total inflow calculation The Inflow property page with the Include Meltwater box checked is shown in Figure 20 The heave rates for different types of subgrade soils can be determined by selecting the calculator icon to the left of the Heave edit box label A Heave Determination dialog box such as the one shown in Figure 21 will open This dialog box presents minimum and maximum heave rates for a variety of soil types with different ranges of minus 200 material In some cases th
56. he permeable base is the same as the PCC pavement The transverse joint spacing is 20 ft The slope in both the longitudinal S and transverse Sx directions is 2 percent The permeable base is made up of AASHTO 57 material and has a unit weight of 100 pcf specific gravity of 2 65 and a minimum permeability of 3000 ft day The thickness of the permeable base is 4 in based on construction considerations Assume a unit weight of 162 pcf for the PCC material The subgrade is Georgia Red Clay which is actually a well graded clayey silt Laboratory tests indicate the particle gradation shown in Table 1 for the subgrade material and a permeability of 0 0033 ft day Corrugated pipe edgedrains having 4 in diameter are used on the project Table 1 Sieve analysis of Georgia Red Clay subgrade 92 67 55 42 31 Determine Use the crack infiltration method to determine inflow Check the adequacy of the permeable base using the depth of flow approach to determine flow conditions Determine the need for an aggregate separator layer and the adequacy of the 4 in pipe TT 43 Solution Prior to starting the analysis the user needs to select the type of units in which to perform the analysis This problem will be solved using English units This system of units is the default option in DRIP and can be selected by checking English under the Options Units menu command Once selected this system of units will be retained throughout the analysis u
57. he time to drain parameter t is plotted against the degree of drainage U It can be observed from the figure that as the degree of drainage approaches 100 percent the time to drain increases exponentially Note that U is expressed as a fraction in the Figure 28 A flowchart depicting the data flow in the Permeable Base property page is shown in Figure 29 TT 35 Time to Drain vs Drainage U Time to Drain hrs Barber Sawyer Drainage U Casagrande Shannon Figure 28 Sensitivity plot for the time to drain analysis time to drain versus degree of Depth of Flow Input q k Ly Calculate H min Input H Calculate d drainage Time to Drain Percent Drainage Percent Saturation J Calculate U Calculate t Permeable Base Figure 29 Flowchart for the Permeable Base property page TT 36 Separator Layer The default screen that appears when the Separator property page is first selected during a DRIP session is the configured for the No Separator option If a design is performed using this option DRIP will determine whether a separator layer is required If instead the user wishes to perform an aggregate separator layer design the appropriate radio button located on the left top of the property page should be clicked The design screen configuration after this selection is made is shown
58. i 225 am n ES i nd 2 The minimum required value of H is ip Vm 116 diad determined using Moulton s design chart SECTION q FHWa TS 80 224 d Permeable Base HOt i E H min 06828 t puy U t N H fi ft dq 77 405 an Edge Drain Pipe DA l qa 75 dn s m Lo 7652 f Q 179102 fd Figure 24 Permeable Base depth of flow property page If the left to right hydraulic design flow recommended in this manual is followed values for several parameters will already be present on this screen For example Sp and Lr will have been calculated on the Roadway Geometry property page qi will have been calculated on the Inflow property page and a value for H may have also been provided on the Inflow property page If these values are not present they may be manually entered in the appropriate edit boxes on this screen However for hyperlinked variables all variables identified with an underline a more correct procedure would be to first identify the appropriate property pages where these inputs should be logically entered and then entering them there In addition to these variables the user will also need to provide a value for permeability k of the permeable base Itis recommended in hydraulic design practice that this value be obtained directly from laboratory testing The laboratory k value if available can be directly entered on this screen Alternatively the user may click the calculator icon located to the left of
59. ibutions and sensitivity analysis plots has been simplified Graphs generated by DRIP can now be imported directly into other Windows applications or saved as JPEG files e Power 0 45 and semi log plots Sieve analyses can be viewed on either power 0 45 or semi log plots 2 0 ORGANIZATION OF THIS APPENDIX This appendix is organized so that both the novice and experienced DRIP users can navigate easily through the program s many different features The content of this manual is also available with the program as online help In an effort to minimize repetition topics that are identical in different parts of the program are usually only covered once in detail when repeated the reader is referred to previous explanations Getting Started In Getting Started the user will learn about the minimum system requirements for running DRIP 2 0 on a personal computer or network DRIP 2 0 installation and the usage of DRIP 2 0 to perform pavement drainage analysis and design General DRIP Operation This section provides an in depth guide on how to use DRIP 2 0 including file handling data input data analysis and report generation Operation of the DRIP plotting package DripPlot is also fully described TT 4 Examples Problems This section provides example problems to assist the user in developing a proficiency in the use of the program Sensitivity Analysis This section discusses the design sensitivity to changes in various para
60. ic gradient Cross sectional area of flow Thickness of permeable base Seepage velocity Discharge velocity TIME TO DRAIN Time to drain Time factor m factor Slope factor GEOTEXTILE Opening size of geotextile in which 95 of the the openings are smaller Opening size of geotextile TT 72 English lb ft 62 4 lb ft cu ft day ft day ft ft sq ft ft ft day ft day hr 9 81 kNm hr LD S Z Q 9 NADA Item Pipe capacity Pipe diameter Slope Manning s coefficient Flow area Wetted perimeter Hydraulic radius Conveyance Velocity PIPE FLOW TT 73 English cu ft day in ft ft sq ft ft ft ft sec SI m s or I s
61. ime to Drain and Depth of Flow analyses performed within the Permeable Base property page It allows the user to determine which sensitivity analyses are to be performed during permeable base design The choices are length slope permeability inflow drain degree of drainage thickness and porosity If any of these menu items is checked a corresponding sensitivity analysis is performed during the permeable base design DRIP defaults to performing sensitivity analysis for all appropriate input variables Options Scale Determines whether the horizontal scale of the sieve analysis plot is logarithmic or Power 0 45 If the former is chosen logarithms of the sieve sizes are plotted against the percent passing to produce a semi log plot If the latter is chosen the sieve sizes are raised to the 0 45 power and plotted against the percent passing to yield an FHWA power 0 45 chart DRIP defaults to a power 0 45 scale for all gradation plots The semi log plot is best used when plotting materials with large amounts passing the 200 sieve for which hydrometer analysis data is available When these gradations are plotted on an FHWA power 0 45 chart the plot is not as visually appealing Semi log plots are also useful when multiple gradations with widely differing sieve sizes are being plotted on the same chart such as in aggregate separator layer design An example comparison of a fine grained material plotted using the Power 0 45 and semi log scales
62. is presented in Figure 6 and Figure 7 Note that the gradations used in both figures are identical The advantage of using a semi log plot scale for this gradation is obvious from these figures On the other hand when plotting coarse grained materials on a semi log chart the gradations have a tendency to fall within one or two logarithmic cycles making the plot more difficult to read The Power 0 45 scale is better for plotting coarse grained materials TT 13 Percent Passing Percent Passing 100 90 80 70 60 50 40 30 20 100 0 001 0 01 D Grain size Distribution Subgrade Sieve Size Example Gradation Figure 6 Sample subgrade gradation plot on FHWA power 0 45 chart Grain size Distribution Subgrade 0 002mm 0 020mm 0 075mm 0 425mm 2 36mm 475mm 12 5mm 25mm A A AT A E T A E TT S A A A A E T JA A TEE P Corn E HHI eer CO Co Ch TSSA O SE O A O O H E 1 1 10 10 0 Sieve Size mm Example Gradation Figure 7 Sample subgrade gradation plot on a semi log chart TT 14 Help Menu DRIP employs Windows HTML Help The contents of this manual are available online and can be accessed by selecting the Help Contents command from the menu Context sensitive help can be accessed from anywhere within the program by pressing the F1 function key The DRIP HTML help is fully searchable by contents index or keyword The contents of the help file can be printed directly using the standard pri
63. ivity requirements can be computed Note that the recommendation at the bottom of the screen changes based on the geotextile type A flowchart illustrating the data flow of the Separator property page is shown in Figure 33 Edgedrain In the upper left hand corner of the Edgedrain property page select either the Pipe or Geocomposite radio button to identify the type of edgedrain The Pipe Edgedrain analysis screen is shown in Figure 34 Typical values for Manning s roughness coefficient Mmanning for smooth and corrugated pipes are provided on the right hand side of the screen If Mmanning for the pipe being analyzed is unknown one of these typical values can be adopted by selecting the appropriate check box Once the user has supplied values for manning Slope S of the edgedrain by default the longitudinal slope and pipe diameter D the calculator icon for pipe capacity Q becomes activated and can be clicked to calculate the quantity After calculating Q there are three options for determining the required outlet spacing The Pavement Infiltration approach is based on the estimated inflow into the permeable base this is the default selection in DRIP The Permeable Base approach is based on the TT 39 No Yes Separator Input Base D15 D50 Subgrade D50 D85 Geotextile Aggregate Select Type Set criteria for Retention Cl
64. kness of the base material H 4 in in the appropriate boxes TT 45 Step 4 Click on the calculator icon next to the variable o to compute the stress imposed by the pavement on the subgrade This will yield a value of 154 8 Ib ft 9 Drainage Requirements in Pavements Unsaved File File Options Help Road Geometry wW S Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain sS 0 0283 Vn 2R Infiltration Ratio Method LR it Crack Infiltration Method r Meltwater p Mateias Infiltration Method 4 Heave in day Base Undefined I 3 Subgrade Undefined B ORA Ko fd Separator None Ne BR if bie Inflow We 4 ft inet 4 2 Gi 042 ate na 3 Hs ft dm aZ d ra H ft m Permeable Base Cg 20 ft LY H ft Yas H o Y H Ns b E kp 0 n U g E o bh ite hr da ian 4 p2 tan E dm tan r Edge Drain Pipe D in W 7 Ne k et i el Ww we Q ta 5 Figure 38 Crack infiltration computation Step 5 Click the calculator icon for determining the quantity of meltwater qm Moulton s meltwater chart appears on the screen On this screen a horizontal red line appears marking the heave rate of the subgrade 0 51 in day Use the mouse to slide the vertical tick line along the horizontal red line 0 51 in day line to an approximate location for a stress of 154 8 psf The value f
65. lassification dm fiiss0 an Low Figure 22 Meltwater inflow computation dialog box Infiltration Ratio Crack Infiltration Input Ic Nc We W Cs kp aa Calculate qi Calculate qi Input Heave Rate Unit Wts thicknesses Include eltwater Compute pavement load o Inflow Meltwater Compute qm Output Output qi qi qm Figure 23 Flowchart for the Inflow property page TT 31 Permeable Base On the top left corner of the Permeable Base property page the user may choose whether to design the permeable base based on depth of flow or time to drain criteria by clicking the appropriate radio buttons It is suggested that total inflow be calculated before attempting to perform the base design using the depth of flow method The Permeable Base property page configured for the depth of flow method is shown in Figure 24 I Drainage Requirements in Pavements example drp g 2 x Fie Options Help Road Geometry z z oadway Geometry Sieve Analysis Inflow eparator Edge Drain oo 0 Roadway Geomety Sieve Analysis Inflow Permeable Base Separator Edge Drain SR 0014 tet ones Type Lr r Time to Drain 2R 17 08 Depth of flow m Materials Base Defined qi 2 28 tam Subgrade Defined Separator Aggregate E k DOD Hd L Sp foo n Pavement WSS Pe q
66. ludes loads from both the pavement surface and the base The user can either directly enter a value for o if it is known a priori or can compute it by first entering values for unit weights and 4 and the thickness Hs and H of the pavement surface and base respectively and then clicking on the calculator icon to the left of the o label When values have been provided for o ksu and the Heave rate the graph icon for meltwater gm is activated The user can click this icon to display Moulton s chart for estimation of meltwater shown below in Figure 22 The vertical axis represents heave rate in mm day and a red line is drawn to indicate the heave rate value The user can move the mouse to drag a crosshair along the red line The horizontal axis represents 4ml Jk The curves on the graph represent multiple values of o in units of lb ft The values of ksu o and heave rate are displayed at the top of the screen in the required units as is the current position of the cursor with respect to the horizontal axis Position the crosshair at a graph location indicative of the value of o and click the mouse button The value of qm will be calculated and displayed at the top of the screen When this dialog box is exited the calculated value will appear in the gm edit box on the Meltwater screen Example Meltwater Computation Assume for this example that the subgrade permeability ksub is 100 ft day the heave rate Heave is 0 1 in d
67. meters which can be used both as a design reference and as an example of the type of detailed analyses that can be performed using the DRIP program 3 0 GETTING STARTED Getting started with DRIP 2 0 is easy especially if you already have installed the Design Guide software program To install DRIP go to the Tools Additional Programs menu on the menu selection tool bar in the Design Guide software and select the DRIP icon This action will install the program automatically Once installed the program can be accessed from within the Design Guide software using the same menu selections System Requirements To run DRIP 2 0 on your computer the following minimum hardware and software requirements must be met IBM compatible PC with at least a Pentium processor 32 MB of RAM 15 MB of available hard disk space One CD ROM drive for installation only Monitor capable of 800x600 resolution Mouse or compatible pointing device Printer optional Also the computer on which DRIP 2 0 is installed must be running Microsoft Windows 95 98 or Windows NT 4 0 operating system or a compatible later version Basically if all the requirements to run the Design Guide software are satisfied then the system requirements for DRIP 2 0 will be satisfied 4 0 GENERAL DRIP OPERATION When the user starts the DRIP program a splash screen appears briefly followed by the DRIP client window shown in Figure 1 The DRIP client window has the follo
68. n Subgrade required Plots Separator optional E Separator Layer Select one Roadway Geometry Inflow Select one Crack Infiltration Infiltration Ratio Meltwater Optional U Aggregate Separator plot available Geotextile Separator No Separator plot available y Y Permeable Base Select one TK Depth of Flow Time to Drain Barber Sawyer or Casagrande Shannon Edgedrain select one gt Pipe Geocomposite Plot for i So ae Aggregate r er 1 Sensitivity Separator Analysis mW H i plots i Figure 11 Interdependencies of DRIP property pages TT 19 The Sieve Analysis Inflow Permeable Base Separator and Edgedrain screens are actually multiple property pages in one By selecting a specific analysis type using the radio buttons located in the upper left hand corner of the property page the analysis performed by that page can be changed For example on the Inflow property page the user can choose either the Crack Infiltration method or the Infiltration Ratio method by selecting the appropriate radio button On the Permeable Base property page the analysis can be set either to the Depth of Flow or the Time to Drain method the Separator property page can design either pavements without or with a separator layer aggregate or geotextile and the Edgedrain property page can
69. nless the user makes a change Similarly the mode of program execution Expert or Normal can also be selected from the Options menu The default is the Normal mode and that will be used in this example The problem solution is presented under several different sections The arrangement of these sections follows the logical left to right approach emphasized earlier An experienced user may however solve the problem using a different sequence of steps Pavement Geometry Step 1 Select the Roadway Geometry tab this is the default program tab to access the corresponding property page Select a uniformly cross sloped pavement section by clicking on the Geometry B radio button Step 2 Enter the value of b as 24 ft 2 lanes of 12 ft each Since the problem statement assumes that the width of the permeable base is same as that of the PCC layer enter the value of c as 0 Clicking the calculator icon for width of the permeable base W results in a computed value of 24 ft Step 3 Enter the longitudinal and transverse slopes in the S and Sx edit boxes respectively Click the calculator icons for both Sp resultant slope and Lr resultant length to compute these parameters The calculations should yield the following values Sr 0 0283 ft ft and Lr 33 94 ft ft The completed screen is shown in Figure 37 The values entered and computed in this property page will be saved and carried forward for later use Note that as soon as the computations
70. nt options provided DripPlot DripPlot is a companion program to DRIP that creates plots of gradations aggregate separator design and sensitivity analysis for permeable bases The information on the operation of DripPlot is provided below DripPlot does not contain file handling or data editing capabilities Changes to the plotted data should be made using DRIP and the results re plotted with DripPlot Once a plot is generated the user may alter the plot s appearance DripPlot allows the editing of titles legends font sizes scales of the vertical and horizontal axes line types line colors and line thicknesses Plots generated by DripPlot can be saved either as device independent bitmaps dib or as JPEG files jpg This allows the user to import data into other Windows programs for report preparation The user may also copy a DripPlot graph using the Copy menu command or shortcut key control C and paste the graph directly into any Windows program that allows cutting and pasting DripPlot Menus The DripPlot menu contains several commands that are common to almost all Windows applications A short summary of these commands is included for completeness Menu commands that are unique to DripPlot are discussed in detail File Menu File New Opens another window with the currently plotted screens This allows the user to have multiple windows of the same plot open This feature is used primarily to view plots with dif
71. o changes in H when the value is very small the curve tends to reach a point where subsequent increases in H no longer have much effect on the time to drain Methodology Figure 58 shows the recognizable plot of time to drain versus percent drainage for both the Casagrande Shannon and Barber Sawyer methods Note that they are very similar actually crossing each other at approximately U 55 This is true in most cases The major difference in the two methods is shown in Figure 59 which plots time to drain versus base thickness for the same data set using each method Note the wider variation at smaller values of H For most reasonable values for base thickness however the two methods will yield similar results Base Thickness The following plots were developed using the sensitivity plotting functionality of the Permeable Base screen for the Depth of Flow method The sensitivity plots presented TT 64 5 4 w gt gt w D to o Time to Drain hrs N K 0 075 0 15 0 225 0 3 0 375 0 45 0 525 0 6 0 675 0 75 Base Thickness m Casagrande Shannon U 50 SR 0 02 LR 10 m k 900 ne 0 3 Time to Drain hrs a N w mn nn nN nm LU Ln Figure 57 Time to drain versus thickness of permeable base Degree of Drainage U Barber Sawyer Casagrande Shannon Figure 58 Time to drain versus degree of drainage for Barber Sawyer and Casagrande Shannon methods TT 6
72. ogging Input Base D15 D50 Permeability Subgrade D50 D85 Compute Separator D12 D15 l Bip D50 D85 P200 Criteria 1 Subgrade D15 C P200 k Separator Check TES Criteria Compute AOS Knin Criteria atisfied Yes Output Separator Gradation Envelope Calculate thickness Separator Output Layer AOS thickness Figure 33 Flowchart for the Separator property page E Drainage Requirements in Payements example drp File Options Help m Road Geometry z z 5 oadway Geometry Sieve is ln ermeable Base Separator Ws h Roadway Geomety Sieve Analysis Inflow Permeable Base Separator Edge Drain E Analysis Type z 004 i teenie Typical roughness coefficients for under drain LR 17 68 Pipe M Smooth Pipe n 0 012 ne s ono Te Moc I Corrugated Pipe n 0 024 ase Defi banning Subgrade Defined D f S Separator None TE goes ae 4 n S r Inflow di 228 am Discharge Rate Approach ase q T 5 Pavement Infiltration Q p ermeavle D dm 118 u 7 Permeable Base L qw Separator tayet Serta ER Time To Drain Geotextile H 07 ft ra i W E didn PE n U Edgedrain pipe t hr 04 4722 fede r Edge Drain Pipe D4 h 9 Q oa a Lo 6249 f s n Q 17810 2 fg Figure 34 Edgedrain pipe edgedrain property page TT 40 Depth of Flow capacity of the permeable base Finally the Time to Drain approach is approach i
73. ometry Sieve Analysis Inflow Permeable Base Separator Edge Drain S ftt 2R Infiltration Ratio Method Lr it Crack Infiltration Method p Materials r Infiltration Method E Heave 0 51 in day Kon fo coss nd y 162 bie fo bit H 075 ft H fis an oS Ys H H G 154 83 Ibert d 2 perder Figure 40 Meltwater computation Subgrade Defined Separator None Inflow qi 0 42 Od dm tan m Permeable Base H 0 33333 ft IG x E hr 04 44811 d r Edge Drain Pipe Belk Jaooo izd SR 0 0283 nO LR 23 34 ft The minimum required value of H is determined using Moulton s design chart FHWA TS 80 224 mal H min 014373 ft ay H foxx ft Bl da en Oan TT 48 Road G ie on r Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain SR 00283 fft paha L S Time to Drain R 33 54 Depthof flow m Materials Base Defined Gi Gm 0 47 anz Permeable base SECTION qa Figure 41 Permeable base depth of flow design Additional Discussion on Depth of Flow Design If the user wishes to perform a sensitivity analysis to see the influence of different parameters on the required thickness the graph icon to the right of Hmin variable in Figure 41 can be clicked DRIP internally performs the calculations over a pre selected range of the independent parameter in this case the required base thickness an
74. on another page Therefore a given variable can appear on multiple property pages For example the parameter W appears on both the Roadway Geometry and Inflow property pages However it is actually an output on the Roadway Geometry property page and an input in the Inflow property page This could lead to some confusion in the mind of the novice user on where to enter the value for parameter W In order to address such situations a hyperlink was provided for all variables that appear on multiple screens All hyperlinked variables are identified by an underline beneath them If a hyper linked variable is selected with a left click of the mouse the program will jump to where that variable should most logically be entered By editing the variable on the analysis page suggested by DRIP the user can avoid inadvertently entering different values for the same variable on different screens Although the user is not required to use this feature it is highly recommended especially for novice users and also when an analysis utilizing only a few of the property pages offered by the program is attempted Error Checking DRIP displays a warning when a dependent variable is about to be changed DRIP also warns the user when data input is inappropriate such as entering a negative unit weight for a material While this feature is helpful for a novice DRIP user these warnings can become an annoyance for the experienced user To aid the experienced DRIP user an
75. on next the parameter clicked to compute the appropriate value The resulting value for time r required for drainage from either methods can be compared to the table on the right hand side of the screen to estimate the permeable base quality of drainage By default the table displays the quality of drainage based on the AASHTO 50 percent drained criteria Alternatively the user can choose to display base drainage quality based on the pavement rehabilitation manual 85 saturation criteria by clicking the appropriate radio button To translate these criteria to the current design parameters the user should select the given equation to calculate percent saturation from the values of n Ne and U The user may have to modify the value of U until it results in a value of 85 As with the depth of flow screen the time to drain screen also provides sensitivity plotting These plots can be accessed by clicking on the graph icon located to the right of the time to drain parameter on the Permeable Base property page Prior to clicking this icon the independent parameters to be plotted on the horizontal axis against the dependent variable need to be selected using the Options Sensitivity menu command The sensitivity plots always include the results computed using both Barber and Sawyer as well as the Cassagrande and Shannon equations A typical sensitivity analysis plot from the time to drain analysis is presented in Figure 28 In this figure t
76. on on the client window DRIP will generate a dialog box prompting the user to save the current project file From here the user can choose to save the file exit the program or cancel the dialog box and return to the program If the user chooses to save the file the dialog box shown in Figure 3 will appear to facilitate data storage Options Menu The Options menu sets the program options available in DRIP Units Mode Sensitivity and Plot Scale TT 12 Options Units This menu command allows the user to toggle between metric and English standard units All input and output variables in DRIP are converted when using the Units menu command A checkmark appears next to the unit type in use English units are used as default in DRIP Options Mode Determines the level of information and warning dialog boxes employed by DRIP These dialog boxes inform the user when a program action or function deviates from those recommended by this manual While this feature prevents the novice user of the program from making mistakes it can become cumbersome for the experienced user When the Normal menu item is checked all warnings and information dialog boxes are displayed The Expert mode suppresses all but the most important warning boxes allowing the experienced user to make informed changes of input data both dependent and independent DRIP defaults to the Normal mode when started Options Sensitivity This option is specific to the T
77. or qm Ksub will appear in the appropriate box When satisfied that the mouse is positioned at the proper stress value click the left mouse button to produce a computed value of qm For this example the mouse is positioned to indicate a value of qm Ksub of 0 91 ft day ft A click of the left mouse button produces a value for qm of 0 05 ft day ft Press OK to return to the Inflow property page The values entered and computed in this screen will be retained and carried forward The Moulton s meltwater chart is shown in Figure 39 and the completed meltwater screen is shown in Figure 40 The computed meltwater quantity qm is updated in the summary page TT 46 Permeable Base Design Depth of Flow Step 1 Step 2 Step 3 Step 4 Select the Permeable Base tab to access the corresponding property page Click on the Depth of Flow Method radio button Most of the variables such as qi qm Sr Lr and H already have values carried forward from pervious screens Note The term dtd is a summation of the inflow from rainfall and meltwater Evaluation of Meltwater Inflow E a 2 x TIT TTT o RS ps kp 232003 ftda Heave fi 3 0 mm day m Meltwater Infiltration dn vk 0 91 50 am 0 05 KENA Average Rate of Heave mmvday Frost Susceptibility Classification Figure 39 Moulton s meltwater chart Enter th
78. r 0 002mm 0 020mm 200 40 3 4 1 2 LUN Percent Passing 1e 5 0 0001 0 001 Sieve Size in Base Subgrade Separator gt Lower bound lt 4 Upper bound Figure 31 Separator aggregate separator Power 45 plot Figure 32 presents the Separator property page configured for performing a geotextile separator layer design Selecting the Geotextile Separator radio button enables this analysis screen As with the aggregate separator layer analysis the design criteria for the geotextile separator layer are also displayed on the right hand side of the screen The criteria displayed are dependent on the user s selections for soil retention criteria steady state or dynamic flow permeability permittivity criteria normal or critical clogging criteria normal or critical and the amount of fines in the subgrade material P200 Material properties for the subgrade should already be in the edit boxes carried over from the Sieve Analysis property page After the necessary values have been provided for all the subgrade parameters the calculator icon in the Separator Layer category box becomes enabled Clicking this button determines the maximum allowable apparent TT 38 IE Drainage Requirements in Pavements
79. rber Sawyer equation is used default The Casagrande Shannon equation yields a value of 0 52 hr Both these results fit the Excellent drainage category The final Permeable Base design screen in shown in Figure 46 Additional Discussion Clicking on the graph icon to the right of the time to drain variable t generates the following sensitivity plots Time to drain t versus Degree of drainage U Time to drain t versus Resultant length Lp Time to drain t versus Resultant slope Sp Time to drain t versus Coefficient of permeability of base k Time to drain t versus Base thickness H Time to drain t versus Effective porosity ne TT 54 i Drainage Requirements in Pavements examples dip Eile Options Help A Paun 7 Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain SR 00283 ftit PRAO Le r Time to Drain 33 Depth of flow m Materials Base Defined n a 63 Subgrade Defined l Separator None E k 2000 fed SR oozes tat m Inflow L 23 34 Gi os an t m dm 092 diaz gas z n joz SECTION dy m Permeable Base H 0333 k U n s n in 50 Drainage AASHTO Guide U 5 x C 85 Saturation Pavement Rehabilation Manual H 0 33333 ft tos m H ET 04 44811 d up gt Excellent 2 Hours S 2 Good 1 D p Edge Drain Pipe Barber and Sawyer Equation a z L D4 in Cassagr
80. ry Calculate W x Calculate Sp Le Output Sa La Roadway Geometry Figure 13 Flowchart for the Roadway Geometry property page TT 22 Sieve Analysis The Sieve Analysis property page shown in Figure 14 is used for gradation analysis and to input other material properties for the base course separator and subgrade layers The spreadsheet style grid on the left side of the property page is used for entering and editing sieve analysis data Sieve data may be entered in this grid in any order and cells may be left blank if data is not available for a particular sieve size Two types of sieve analysis data entry forms Range and Value are available to the user The Range analysis selected by the corresponding radio button near the top left side of the property page allows the user to input a range of sieve data that a particular material is bracketed by The Value analysis requires the user to input a single value at sieve sizes for which data is available The numbers entered are the percent passing a particular sieve by weight and therefore should range from 0 to 100 For example 100 passing should be input as 100 and 55 3 passing should be input as 55 3 I Drainage Requirements in Pavements example drp E 215 File Options Help r Road Geometry 5 lt Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain W 2 ft S a G Val SR 0041 fit Range alue
81. ry name Care should be taken not to use file control characters Cancel Figure 16 Add gradation to Material Library After the material is saved to the Material Library that description will appear in the library pull down list box If the user edits this file by entering new numbers in the Sieve Analysis spreadsheet the material type will return to lt user defined gt The lt user defined gt material type is a temporary name and will not be saved if a specific material is selected from the Material Library Materials that are added to the Material Library remain in the library until the file is removed using the Remove button or deleting the appropriate sgd file from the GradFiles subdirectory When a user starts entering data in the sieve analysis spreadsheet the name of the material changes to lt user defined gt It is possible to have separate lt user defined gt entries for the base subgrade and separator layers Besides gradation analysis the Sieve Analysis property page requests several other user inputs These values can be entered directly or calculated using empirical formulae Permeability k of a layer can be calculated using Moulton s empirical formulation which requires particle size and porosity information DRIP allows the user to compute porosity after the unit weight and the specific gravity of the material is entered A more accurate estimation of porosity can be gained through laboratory tes
82. s based on the time required for a specific percentage of the water to drain from a saturated permeable base Any of these approaches can be selected by clicking the appropriate radio button When a discharge rate approach is selected in this manner the equation that will be used to compute the outlet spacing is displayed on the screen Edit boxes to enter values required to compute these parameters also appear on the screen If the user has followed the suggested design flow values will have already been provided for each parameter used Therefore the user can quickly calculate the required outlet spacing for each approach and compare the results The Geocomposite Edgedrain analysis screen shown in Figure 35 differs mainly in the calculation of edgedrain capacity Q For a geocomposite edgedrain outlet pipe spacing Lo is actually a parameter used in the calculation of Q along with slope S of the edgedrain initial height of flow Dj final height of flow D2 and flow coefficient Cg Thus the calculation of the outlet spacing L is an iterative process The program begins with an initial value of Lo of 100 m calculates Q then iteratively recalculates Lo The process is repeated until a result is converged upon 759 Drainage Requirements in Pavements example drp 2 xi File Options Help m Road Geometr z 9 Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain W 125 f SR 004 ftt Snes j Flow factors for som
83. se and native subgrade If there is a need determine whether the proposed separator layer is adequate Solution Step 1 Click on the Sieve Analysis tab to enter and store the given base subgrade and separator layer gradations Step 2 Click the Include aggregate separator check box TT 57 Step 3 Step 4 Step 5 Table 2 Gradations of pavement materials Base Separator E oe S a a E EE eae eo E pain Cd H wet as E a es T a ae ee T T T 0 001 mm hydrometer To enter and save the gradation of the given permeable base click on the Base radio button on the Sieve Analysis page Enter the percent passing information for the permeable base given in Table 2 in the grid provided on the left side of the screen after selecting the Value radio button After all the information is filled in click on the Add button under the Material Library category box and save the entered gradation Now by clicking on the calculator icon under the Gradation Analysis category box the user can compute the percent passing the No 200 sieve Pann the particle sizes Dx e g Dio D12 Dis and the Cy and Cc values for the permeable base Repeat the data entry and analysis performed in Step 3 for the separator and subgrade layers Once all the gradations are entered and the corresponding properties computed click on the Separator tab to access this property page All the relevant D values for each of the layers should already
84. t view window Chart Help 18 x Ba Z Required Base Thickness vs Base Course Permeability 1600 2000 2500 3000 3500 4000 4500 Permeability Hd L 17 68ft S 0 0141 0 0 702392 Figure 25 Sensitivity analysis for the depth of flow method base permeability versus base thickness TT 33 DripPlot Length 2 5 x File Edit view Window Chart Help 181 x Required Base Thickness vs Length of Flow Through Base 24 Length of Flow ft S 0 0141 g 0 702f Sia tt 2 k 100 00ttiday Figure 26 Sensitivity analysis for the depth of flow method length of flow versus base thickness E Drainage Requirements in Pavements example drp File Options Help Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain Subgrade Defined Separator Aggregate m Inflow di 228 daz Am 116 ean m Permeable Base H 1 ft U 50 x t a hr qd 0774 ddn r Edge Drain Pipe D4 in Lo 7652 ft Q 178102 du m Road Geometry W 125 f F anai AA Analysis Type Time to Drain LR 1768 ft C Depth of flow m Materials Base Defined P Ee 100 00 ft d 11 0 0141 fue 17 68 E Bl s x n ores U n s n n Hh ft u f Barber and Sawyer Equation Cassagrande and Shannon Method gat ny SECTION qa
85. the following section headings e General DRIP features DRIP icons context sensitive help hyper linking error checking e DRIP Menus File handling Help and Options e DripPlot Graphing and plotting package for DRIP e DRIP Property Pages Tabbed property pages each containing one of the six sub processes required for a complete drainage analysis e Project Summary Summary of important input and output data for the program TT 6 9 Drainage Requirements in Pavements Unsaved File File Options Help r Road Geometry wW ft SR fret Lr ft r Materials Base Undefined Subgrade Undefined Separator None m Inflow E E ef Geometry A Geometry B qi Oan idn Im r Permeable Base Geometry A Edgedrain pipe Roadway Geometry Sieve Analysis Inflow Permeable Base Separator Edge Drain Subgrade Geotextile Trench Figure 1 The DRIP client window General DRIP Features Geometry B EDGE DRAIN PIPE cce Permeable Separator layer DRIP has many features to assist the user in operating the program including special icons context sensitive help hyper linking of variables and input data error checking DRIP Icons There are three of types of icon buttons in DRIP Calculator Graph and Balance The icons are illustrated and explained below Calculator icon Allows the user to perform a calculation
86. this parameter to estimate permeability based on the gradation of the permeable base aggregate This action will take the user to the Sieve Analysis property page where the computation can be made TT 32 However it must be noted here that the underlying statistical relationship that estimates permeability from the gradation data was derived for materials with a significant quantity of material passing the 200 sieve Therefore it may not be very suitable for estimating the permeability of open graded materials which typically have very low percent passing the 200 sieve When values have been provided for gi k Sr and Lr the calculator and graph icons beside the Hin parameter are activated If the calculator icon is clicked at this point the program will use the equations underlying Moulton s permeable base design chart to calculate the minimum required thickness Hmin of the permeable base The user should check to make sure that the input value of H is greater than the minimum thickness required Hin Clicking the graph icon to the right of the Hmin edit box will plot the calculated value of Hin over a given range of values for the independent parameters selected in the Options Sensitivity menu command This allows the user to analyze the sensitivity of the design to variations in inputs A few typical sensitivity plots for the depth of flow method are shown in Figure 25 and Figure 26 DripPlot Permeability j E j M o x Fie Edi
87. time to drain continues to decrease over the entire range of slopes presented Theoretically the base will drain even if the slope is flat however it is questionable practice to apply the design procedure to flat slopes Resultant Length Figure 56 shows the effect of resultant length of drainage path on the time to drain parameter The relationship is quite linear in the reasonable range of Lr 4 m and greater TT 62 Time to Drain hrs Time to Drain hrs N K K w 0 200 400 600 800 1000 1200 1400 1600 1800 Permeability mid 2000 ee Barber Sawyer U 50 SR 0 02 H 0 2 m LR 10 m ne 0 3 Figure 54 Time to drain versus coefficient of permeability D n F gt o gt H w D LU 1 8 0 6 Resultant Slope m m Barber Sawyer U 50 H 0 2 m LR 10 m k 900 md ne 0 3 Figure 55 Time to drain versus resultant slope TT 63 Time to Drain hrs Un 0 5 10 15 20 25 30 35 40 45 50 Resultant Length m Barber Sawyer U 50 SR 0 02 H 0 2 m ne 0 3 k 900 mid Figure 56 Time to drain versus resultant length of drainage path Thickness The effect of base thickness is plotted in Figure 57 The time to drain is reduced by increasing the layer thickness While there is large sensitivity t
88. ting If such data are available they should be used in place of the empirical formulae TT 25 Two analysis methods are supplied for computation of the effective porosity ne the water loss method and the water content method As the user clicks the appropriate radio button for each method the equation changes accordingly For fine materials such as subgrades the water content method is recommended In order to use this method to estimate ne the approximate value of the water content should be entered For coarse materials such as permeable bases the water loss method is recommended To use this method the user should first select the Water Loss Method radio button The Water Loss dialog box similar to the one shown in Figure 17 opens automatically This dialog box contains a table that shows values for water loss for P2090 of 0 2 5 5 and 10 for either gravel or sand materials The user should indicate the type of fines filler sand or clay contained in the material by clicking the appropriate radio button If the user has already calculated P29 for the given material that value will appear as a column in the grid shown in Figure 17 Two water loss values one for sand and other for gravel are automatically computed and displayed in the dialog box in the P299 column The user should then select one of the water loss values corresponding to the material being analyzed with the screen cursor Once the selection is made and the
89. wing features TT 5 e A menu bar across the top which includes the File menu the Options menu and the Help menu e A program summary column on the left side of the screen that displays all the important DRIP outputs The summary information is continually updated as the analysis progresses e A series of six tabs arranged from the left to right titled Roadway Geometry Sieve Analysis Inflow Permeable Base Separator and Edgedrain When selected these tabs display the respective property pages Each property page has the following common elements edit boxes for data input on screen graphics describing the problem and calculator and or graph icons for output computation In addition some property pages have module specific analysis options e g the Edgedrain property page allows the user to choose between pipe edgedrain or geocomposite edgedrain analysis types All the hydraulic design and analysis in DRIP takes place within these property pages DRIP has many features that can be used from anywhere within the program These include file or project actions such as saving and printing as well as the functions of certain function keys and on screen buttons This chapter describes many such features that are available throughout the program In addition a detailed description of the functionality of each tabbed property page is also provided The description of the DRIP program features and operation is broken down and presented under
90. y above and below Window Tile Arranges plots side by side in the DripPlot window Window Arrange Icon Arranges minimized plots along the bottom of the DripPlot window Chart Menu The Chart menu is used to modify the appearance of DRIP plots DripPlot is designed to be a simple straightforward plotting package It is not completely customizable Ifa user wishes to make highly customized plots it is suggested that the information from DRIP be output using File Export Summary to create an HTML summary file This summary file can be imported directly into most standard graphing packages Chart Titles and Labels This command allows the user to edit the axis label and plot title text The user can also change the font size of the all labels and titles The Titles and Labels dialog box with sample graph and axes titles is shown in Figure 9 The default font sizes for the titles are also shown in the figure Once the user is finished with entering the desired option values on this screen the changes can be accepted by pressing the OK button Chart Lines Legends and Scale This command allows the user to edit the legend labels and their font size line color line type and line thickness For graphs that do not involve gradation plotting it also allows the user to adjust the minimum and maximum values displayed on the X and Y axes The tick marks can also be adjusted for scaling the axes The Lines Legends and S

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