Elmod 6
Quick Start Manual
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Table of Contents 1. Introduction _______________________________________________________ 3 2. Compatibility ______________________________________________________ 3 3. Installation ________________________________________________________ 5 4. Registration Procedure ______________________________________________ 6 5. The Main Menu ____________________________________________________ 8 5.1 Menu Items___________________________________________________________ 8 5.2 Navigating in the Menus _______________________________________________ 14
6. Settings __________________________________________________________ 15 7. Projects and Data Files _____________________________________________ 19 7.1 Creating a New Project ________________________________________________ 19 7.2 Importing FWD Data Files. ____________________________________________ 20 7.3 Opening Projects and Data Files ________________________________________ 22 7.4 Delete Options _______________________________________________________ 24
8. Viewing and Editing Data File _______________________________________ 25 9. Entering Structural Information _____________________________________ 26 10. Performing Backcalculation ________________________________________ 29 11. Performing Designs _______________________________________________ 31 11.1 Overlay Design _____________________________________________________ 31 11.2
New Design ________________________________________________________ 34
12. Viewing Results___________________________________________________ 36 12.1 Graphs and Tables___________________________________________________ 36 12.2 Options ____________________________________________________________ 38 12.3 Sectioning __________________________________________________________ 39 12.4 Tools ______________________________________________________________ 40 12.5 Editing Graph Layout ________________________________________________ 41
13. Parameter Setup __________________________________________________ 43 13.1 Seasons ____________________________________________________________ 44 13.2 Materials ___________________________________________________________ 45 13.3 Vehicles and Wheels _________________________________________________ 51
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1. Introduction The purpose of this manual is to assist you getting started with the basics of Elmod 6 FWD data analysis. It gives a brief overview through the menus and procedures needed for importing files, doing backcalculations and designs. Only issues regarding the functionalities of the Elmod 6 Basic module are covered. For guides and information about the optional modules FEM/LET/MET, PCN and LCCA please refer to the HELP file in Elmod. The HELP file associated with Elmod6 gives more detailed information as well as you will find general documentation, examples and references.
2. Compatibility PC and Windows. Elmod is designed to run on a PC under Microsoft Windows operating systems. Elmod has been tested with Windows 2000, Windows XP and Windows Vista, but is assumed to run also with Windows NT, Window ME and earlier versions like Windows 98. The required minimum screen resolution is 1024 x 768 To be able to generate reports, you will need to have an installation of Microsoft Word for reports designed for printing, and Microsoft Excel for exports of tables for further processing. Earlier versions of Elmod Elmod 6 can read and convert Elmod 5 databases. Since Elmod 6 has a changed database format, it is necessary for Elmod 6 to create an Elmod 6 database from the Elmod 5 project. If you from Project Open select an Elmod 5 project database, you will get the following message:
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Click Yes to proceed, and you will be asked for location and name for the Elmod 6 project database:
As a default Elmod suggests the same folder, and name of the project database with _E6 added to the name. When you click Save the new database will be created and opened ready to be used. Databases and parameter files from Elmod versions 1 to 4, cannot be read automatically by Elmod 6. Contact Dynatest in case you need assistance with converting old data.
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3. Installation From a CD: Insert the CD and run the file Elmod6_Setup.exe. From an FTP download: Download the file Elmod6_.zip to a directory, and unzip the files to a temporary directory. Run the file Elmod6_Setup.exe from this directory. SETUP procedure: Dpending on the Operating System you may first receive a Security Warning window. If so click the approipriate button to continue. On the Welcome window click Next to continue the installation. Next you will have a Customer Information window. You don’t have to fill in anything, just click Next to continue. You can now accept to install Elmod6 in the default directory: C:\Program Files\Dynatest\Elmod6 or you can change the location using the Change function. Continue the installation by clicking Next. On the following window click Install to start the installation. When installation procedure has finished, click Finish to exit. In some cases you may be asked to restart the computer for changes to take effect. It may happen that during the installation, you will be prompted because a file could not be updated due to Windows protection of the file. In this case just click OK to continue the installation. The SETUP program creates a shortcut in the Windows “Start” menu, from which you can start Elmod6:
Also an Elmod6 Shortcut is created on your desktop.
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4. Registration Procedure Each installation on a new computer requires a request for a license file for the specific computer. When starting the Elmod program, a registration form will automatically pop up, if no license is present for the computer. This registration form must be used when requesting the license from Dynatest.
If you do not wish to register at this point, you can press the Return to menu button, and the program will continue to the main menu. The first 5 days you can use the program with all facilities without a license file. Hereafter the program will convert to a “DEMO”, where you are only allowed to open a demo file located in the Elmod6 program folder. If you would like to request the license file, then press the button Create Mail to Dynatest. You will following be asked to enter the name of your company or institution, and to identify your home country from a list. Next you will have the window, as shown below, where you can accept or reject the license conditions. Please use the scroll button at the right to see all text in the license agreement.
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If you accept the agreement the program will start up your default e-mail service, and prepare a new e-mail with certain information placed in the header lines. All you have to do is to send the e-mail. Dynatest will mail back the license file, normally within 24 hours. If you choose not to accept the agreement, then the program will convert into a DEMO version. If one of these situations occurs: -
You don’t have e-mail service on the computer. The e-mail service does not start automatically. The wrong e-mail service is starting. The header line is empty.
Then please use the other button I don’t have email facilities on this computer. This procedure will save the necessary information to a text file “Mail_to_Dynatest.txt” in the folder: C:\Dynatest\Elmod6. Next you can attach this file to an email to Dynatest using your normal e-mail service.
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5. The Main Menu Following you will have a brief overview of menu items and shortcuts available. For details about the functionalities please follow the references.
5.1 Menu Items
Some of the menu items may be disabled, if they have no relevance at the current stage, e.g. you cannot view a data file before you have opened one, and you cannot do a design before you have done a backcalculation.
Project This opens a submenu with access to handling projects and files:
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Select Database to manage project databases:
Open opens a browser to locate a previously created project database. Create new opens a browser to allow selection of location and name for a new project database Compress database is a facility to compact and repair existing databases. It is only enabled if no project database has been opened. Select Datafile to manage files in the project database:
Open from database is used when an existing file in the project database should be the current file to process. Import FWD file to database opens a file browser to locate FWD files to import. Import from several directories can be used to locate FWD files to import if they are located in different folders. Merge files is a facility to combine two imported files into one. Rename file allows you to give the currently opened file a new name. Select Batch to run backcalculation for a range of files in one operation. All selected files must be present in the current database. Select Delete Options for access to various possibilities to delete analysis results and files.:
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Select Recent Files for fast access to previously opened files.
These can be accessed even if no project is open and even if they belong to another project than the current one. The accessed file’s project database will automatically become the current one. (See 7. Projects and Files for details.)
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Review Data Clicking Review Data gives access to view and edit information from an opened data file. Temperature curves can be viewed and edited, and it is possible to split files. (For more information see the Help function accessible from the Elmod Main Menu).
Structure Click Structure to enter pavement thicknesses and materials, and to define subsections. Further it gives access to define GPR thickness data, and to input information for joint calculations. (See 9. Entering Structural Information).
Moduli Click Moduli to get access to start a backcalculation of layer moduli. You have access to Radius of curvature method, to Deflection Basin Fit method, and to the optional module FEM/LET/MET. (See 10. Performing Backcalculations)
Plot Click Plot to access the facilities for presentation of deflections data and results of calculations. There are facilities for graphics, printed reports and export to various file types. (See 12. Viewing Results).
Parameters Click Parameters to view and edit a parameter setup for designs. If no project is open you have access to the default parameter setups, otherwise you have access to the parameter setups stored in the current project database, and the possibility of saving edited setups both as default and as project specific. (See 13. Parameter Setup) Design Click Design to perform either overlay design or new design:
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Overlay design is used to calculate required overlay thickness on existing layers. New design is used to calculate completely new structures, not using any backcalculation results. To carry out a design you have to select a parameter setup and to enter information about layer material types and traffic (See 11. Performing Designs).
LCCA Click LCCA to get access to the optional module LCCA (Life Cycle Cost Analysis). This is only available if you have license for this module. (For more information see the Help function accessible from the Elmod Main Menu).
PCN Click PCN to calculate Pavement Classification Numbers for Airport facilities. This is only available if you have license for this module. (For more information see the Help function accessible from the Elmod Main Menu).
Options Clicking Options brings up this submenu:
Edit Aircraft Database is used to add, delete and modify information in this database delivered as a part of the Elmod software package. The database contains information about aircraft details, and is used in connection with setting up load configurations for aircrafts in Parameters, and as the source for ACN values, when using the PCN facility. Click Edit Geophone Setup to get access to select/deselect geophones used for input to the backcalculation. Click Edit Temperature Table to make changes to the defined asphalt modulus / temperature relations defined as tables.
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Settings Click Settings to access some overall settings for Elmod6, like language and unit system. Correct settings must be entered before creating a new project database. (See 6. Settings).
Help Clicking Help brings up this submenu:
Help File brings up this Help system. Registration gives access to apply for license file. (See 4. Registration Procedure) About gives information about program version and licenses.
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5.2 Navigating in the Menus With the Mouse When moving the mouse cursor over a menu item (label or related icon), you will automatically see the submenu if there is one, and you can continue to move the mouse to the submenu item you want to go to. Submenu items can have a new submenu level. In this manner you can reach any menu item or submenu item without clicking the mouse. First when you have highlighted the desired item, you need to click to activate the item. The advantages are that you can move fast around in the menus and save a lot of mouse clicks. The drawback is that you need to be a bit more careful with the mouse movements, because a selected submenu window will disappear if you move the cursor outside the submenu window. This drawback is reduced a bit by making the submenu items larger, which also allows more space for the related icons. From the keyboard. The whole menu system can be controlled without using the mouse. Instead the key with the first letter of the menu label can be pressed (not case sensitive). To open a database you would then press: pdo and (p for Project, d for Database, o for Open and to activate) You will see that the mouse cursor is following your choices, so it’s easy at any time in the process to let the mouse take over.
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6. Settings Select Settings from the main menu to access this facility. This allows setting a number of general parameters in Elmod, and it must be checked that the settings are correct before creating a new database. General
Settings on this tab are defaults for any new database that is created Changes will be reflected for both new and existing databases, except Printer Setup which needed to be checked for each run, as it may be changed by the use of other applications. Language contains a selection of languages which can be used in the user interface. Elmod is delivered with English as standard, and prepared for translation into other languages if feasible. In the current list of languages only few of the choices are active, and they may not be updated in the current release, as this will only happen in cooperation with clients demanding translations. Units. Elmod can work with either the SI Metric system or with the US Customary system. Switching between the two systems of units can only be done when no project database is open. Once a project database is created with the defined unit system, it cannot be changed within the project database.
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Weather Report Site indicates a link to a website where temperature information is available. In the Estimate Moduli window, there is an option to click the Link button, when using Bell’s equation for correcting surface temperature to mid-depth asphalt temperature. Clicking this button will open the website to allow searching for temperature information for the specific area and period. Tooltips activated. Elmod6 comes with a comprehensive tooltips functionality, giving information boxes when moving the mouse pointer over menus, buttons and text fields. This is useful for new users of Elmod6, but after a while when getting experienced with the functionalities you may wish to switch it off, as they can be annoying if you don’t need them. Printer Setup. This allows changing the default printer as all reports now goes into Microsoft Word or Microsoft Excel you can just as well set the default printer in these applications. The only exception is the print graph facility in the PLOT program, where the graphics are sent directly to the printer.
Technical
If a data file is open the settings on this tab will always be saved to the current project. By checking Save also as permanent the changes will also be save for use with new projects created. If no data file is open changes will be saved as permanent changes. Sort data by chainage. This is used when importing FWD files. Usually it is most convenient to have the data sorted by chainage because pavement structure
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data are entered by chainage and some plotting features like sectioning and XY graphs only works if stationing is in increasing order. One possible reason to keep the original order of the test points is if the file contains measurements in both directions of a road, and the two directions have to be analyzed separately. In this case the sorting can be unchecked and the Review data facilities can be used to split the file into two more easily than if the data were sorted. Automatic insertion of seed values. In the Structural data window where you define the pavement structure, Elmod will use this setting to determine if seed moduli should be inserted automatically when selecting materials. If it is switch on, Elmod will insert the materials reference moduli as defined in the Parameter setup. The seed moduli are used as start values in the iteration procedures for calculating the layer moduli. Use moduli restriction. In the Parameter setup you can set a minimum and maximum allowable modulus for each material. If you switch on the restriction Elmod6 will use these values in the backcalculation of moduli, and not allow the modulus to exceed these values. Distress reduction factors. These values relate to a project database, and can only be set when a project database is open. They can be relevant to use if FWD tests have been performed on cracked surfaces, and the FWD operator during the tests have indicated this in the data file using the facility in the Field program where he can indicate moderate cracking or severe cracking. When the surface is cracked it may be impossible or irrelevant to try to backcalculate the modulus of the top layer. Instead the modulus of the top layer can be fixed to an estimated value, and Elmod will then reduce this fixed value with the factors entered for moderate and severe cracking. Load transfer. When joints have been tested in relation to jointed concrete pavements, the load transfer can be calculated. The load transfer efficiency can be calculated according to two different methods. Both methods make use of the deflections from the two geophones positioned at each side of the joint, and a bending factor from the mid-slab test using the deflections from the same geophones. Westergaard’s equation provides the actual load transfer between the two slabs, whereas the FHWA equation is the deflection ratio. {bmct Settings_1A.bmp} D refers to deflection, J and M to joint and mid-slab and 1 and 2 to first and second geophone chosen for the joint calculation. Em factor. This factor’s default value is 1. The Em factor is a design factor. The “measured Em” corresponds to the dynamic FWD load. If the subgrade design criterion was based on a static plate loading test, and you know that the dynamic modulus is 1.3 times the static modulus, for example, then you would enter this factor, and the design part of the program will use the static Em. Similarly if you have been using results of a triaxial test, and you know that they give 0.3 times
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the dynamic FWD value (as claimed by AASHTO) then you would enter a factor of 1/0.3 = 3.33. k factor. A similar factor can be applied to the k – value, used with Westergaard’s equations, and also used for reporting the subgrade category with PCN for rigid pavements. Notice the “dynamic” k-value is considered to be less than the “static” derived k-value, in which case the entered factor must be less than 1. Colors
Changes on this tab will be valid for both current project and for new created projects. You can select colors for various objects in the windows. For window background color you can specify a graduation by setting different top and bottom color. Level 1 refers to the Main menu window, and Level 2 refer to windows that open on top of the main window, likewise Level 3 refers to windows that opens on top of Level 2 windows. Click in the boxes to change the colors. Click the Change to factory settings button to reset colors to the default settings as they came with the installation.
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7. Projects and Data Files A Project is defined as a collection of data files. The project name refers to the name of a single Microsoft Access database where to which the data files have been imported. Elmod6 can only work with data files that are imported into a project database. A Data File is a collection of test points measured with the FWD/HWD, and stored in one file named by the operator during the field testing. When a new set of data files have been brought in from the field, the first step will be to create a new project database for later import of the data files. The idea is that you can keep all data files belonging to a specific project in a single project database. This may be a collection of files from an airfield, from a single road, or from multiple roads belonging to the same contract. A reasonable number of files in one project database would be from 1 to 50 or 100, but there is no upper limit, except that the size of the database could grow to an unmanageable size or the program performance would slow down at some stage. The second step is to import the data files. Even if only one data file has to be analysed it must be imported into a project database. Once this has happened you will not need the FWD data file any longer. (Except for backup purposes). Analysis can now be performed by opening the proper file from the project database, and all results will go into the project database. If you are going to analyse or view results from an earlier created project, the procedure is to open the project, and next to open the data file from the project. Alternatively you might find the file in the list of recent files in the Project menu. This will automatically open both the project database and the data file.
7.1 Creating a New Project
From the main menu select: Project Database Create new The browser window as shown below will open and you can select where to create your project database, and which name you want to assign to the database. The file extension must be “.mde”, which Elmod will recognise as an Elmod Project Database.
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When you click Save, Elmod will create the project database, and the default Parameter setups will be copied to the new database. This project database will become the current database. The Main Window’s title bar will always display the currently opened project:
7.2 Importing FWD Data Files. To import a FWD data file, or multiple data files located in same directory, select from the Main menu: Project Datafile Import FWD File to Database Elmod 5 can open all standard FWD files stored by a Dynatest FWD or HWD regardless of field program version or file format. A standard dialog box enables choice of directory and subdirectory location. By default, all files having extensions as FWD, F10, F20, F25 and MDB are shown. If another extension has been selected by the user e.g. DAT, these can be displayed in the file dialog boxes by selecting "All files" in the File Type Box. The File Open Dialog Box will open as seen below.
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Files with standard extensions will be displayed from the selected directory. Notice that the new MDB format from the Dynatest Field Program can also be imported. You can now select a single file or a range of files to be imported. To select a range of files use the standard Windows functionality or .
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If you select a single file, you will have the opportunity to store the file under a different name, when you have clicked the OK button:
The last file in the import will automatically become the currently opened file, as you will see in the Window’s Title bar:
If you select Project Datafile Import From Several directories you will have a more convenient way of importing files one by one located when they are located in different directories. You also have the possibility to change the filename for each file.
7.3 Opening Projects and Data Files
To open an existing project select: Project Database Open You will then get the usual File Open Dialog Box, from which you can browse to the location of the database. Only files with extension “.mde” will be listed. When you have clicked OK to open a database, you can open an data file from the database by selecting: Project Datafile Import If the project database only contains one file, this file will be opened automatically. If there are more files you will get the list of files for selection.
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Click the data file you want to work with, and click OK. If the specific data file is among the list of recent files in the Project menu, you can also click the file name there, and both Project and data file will open automatically.
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7.4 Delete Options The Delete Options gives you following possibilities:
Deleting complete project database will delete the project MDE file from the hard disk with all imported files. Deleting a file from the project will remove all information including any results about the specific file, which is currently opened. Deleting all results from the file will delete the results of all calculations that have been made for the currently opened file. Deleting designs from file will delete all design calculations for the currently opened file, while the results of backcalculations will remain. For all choices you will be asked to confirm the process.
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8. Viewing and Editing Data File To view and edit various information from the currently opened data file select Review Data from the Main menu.
What you see is the file information stored in the project database. Any editing to this information will not affect the original FWD data file, which was used during import. In the table with test points and deflections you can edit values in the white coloured cells. To edit, click the cell and make the correction. Press or click another cell to accept changes. Nothing will be stored to the database until you press the button Save New Data. To reject your changes, just click Cancel. The columns T,asp and T,surf in the data grid refer to the recorded asphalt temperature and surface temperature during testing. The columns JointID and PosID are identifiers used for recognising the position of the FWD during measurements of jointed pavements, where tests at corners and edges are used to calculate joint conditions. The button View Geophone Positions will open a window, with a drawing of how the geophones have been positioned during testing. This is useful when measuring with a Rear Extension Bar or a Star Bar.
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9. Entering Structural Information When a data file is open, you can enter layer thicknesses by selecting Structure from the Main menu. The following window will open:
In the example above you will see a 3 – layer structure (including subgrade) defined as 200 mm of wearing course layer on 300 mm of base layer. For a 3 – layer system this is all that is required to perform a backcalculation. Information about material types will not be required before design suggestions have to be calculated. You can divide the data file into subsections with different layer information using the Add Section button, and set the chainage of each subsection in the From and To data fields. Click OK to save the changes and return to the main menu.
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In the figure below you see an example where additional information has been entered:
The file has been divided into 3 subsections, and material types have been defined, by first selection a parameter setup and following material type for each layer can be selected by clicking in the material input fields. If you click the button View Structure you can get graphics reflection the defined sections and input values:
PCC is layer No. This is used to indicate layer number for a PCC layer, counted as 1 from the top. This is relevant if PCN is to be used or in case of jointed pavements with joint tests. Use PCC Joint ID Numbers Check this option, if the joint calculations have to be included in the analysis. This is only possible, if the tests have been made on PCC slabs, with measurements on both slab centre and slab joints using the rear extension bar.
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The joint ID numbers identify the position of the measurement on the slab, and are given by the operator during testing. Use GPR Data An alternative to enter layer thickness for each section is to use this facility to use point related data for layer structure (like results from GPR testing). In this case check the option and click Import/Edit to get an input table for the data. It is possible to import the data from a text file or from an Excel spreadsheet. In the analysis, Elmod will for each FWD test point, search among the GPR data to find the closest point with thickness information. (For more details about the options in this window see the Help function accessible from the Elmod Main Menu).
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10. Performing Backcalculation Start the backcalculation module by clicking “Moduli” from the Main menu, and you will see the window below:
Select Drops If you have more than 1 drop for each test point in the file, you can specify the drop(s) for the analysis. One or more drops may be used at a time Select Sections If you have divided the file into more subsections, you can specify the section(s) for the analysis. Temperature Status This gives an overview of which temperatures that are available in the data file, and the minimum and maximum recorded temperatures. From the Review Data window have access to see graphics of the recorded temperatures.
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Asphalt Temperature Here you decide which should be used as the asphalt temperature in the calculations, making it possible to correct the asphalt modulus for temperature to be used with design. If manually recorded mid-depth asphalt temperatures are present in the file, select the Use as recorded option. In the Temperature Status frame you can see if asphalt temperatures are present. If only surface temperatures are recorded you can select either to use them directly as the asphalt temperature (not recommended), or you can use them as input to Bell’s equation for calculating the asphalt temperature as a function of surface temperature and previous day average air temperature. In the latter case you must enter this average temperature in the temperature field. Clicking the Link button opens a website with worldwide temperature measurements. Which website to open is defined in Settings. You can select the Not required option if there is no temperature sensitive materials in the pavement structure, or if the backcalculation results are not going to be used for design. Fix depth to Rock Checking this option will regard the input from the Structures window as the exact depth to bedrock, consequently Elmod will not calculate a depth within the maximum range given. The Radius of Curvature method is based on the Odemark-Boussinesq method of equivalent thicknesses (MET) using the outer geophone readings to determine non-linear characteristics of subgrade, and the inner geophones to determine the upper pavement layer moduli. The stiffness of remaining layers is then calculated based on the overall pavement response to the applied load. The Deflection Basin Fit method still utilizes Odemark-Boussinesq methods, but an additional iteration process will utilize the convergence criteria based on degree of fit between the overall measured and calculated deflection basins. Various options can be set to control the iteration process. The grid is used to display results from the iterations during the backcalculation. Click the Calculate button to start the backcalculations. When finished, you can select Plot from the Main menu to view results. (See 12. Viewing Results). (For more details about backcalculations and settings see the Help function accessible from the Elmod Main menu).
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11. Performing Designs
Overlay design requires that you have performed backcalculation generating elastic moduli for the pavement layers. You can design based on the whole structure or part of the structure by removing top layers. New design does not make use of FWD results or backcalculation. You can define a structure and calculate the design thickness of the top layer.
11.1 Overlay Design
Sections with backcalculation results are listed in the grid. In the column Chosen you can mark sections to be included in the design by clicking in the field.
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If parameter file and material types were already entered in the Structural input, then this information is shown in the grid, and the name of parameter file used. If the fields with the layer’s material type are empty, you have first to select which parameter file to use, and then by clicking in the fields identify the material type for each layer from the popup list. If you have multiple sections, you can enter the material type for the first section, and following click the button Copy first structure to copy this to the other sections. Base design on Here you select if any existing layers should be removed before design of new overlay. When you select an option, you will see in the grid which layers are removed indicated by a greyed font color. If you select Existing pavement then you have an option to mill a part of the top layer, by entering a value in the frame Milled from layer 1. The value entered must be smaller than the thickness of the top layer. If you select Existing unbound layers then you can in the same way have a part of the first granular layer removed. If you select Existing subgrade then you can specify an improvement to the subgrade moduli determined from the backcalculation by entering a percentual increase. Entering a value of 25 means the existing moduli will be multiplied with a factor of 1.25 Add new layers Here you define which layer(s) to add on the top. In the usual case where you design for an overlay of the existing pavement, you will enter one bound layer type. Click in the combo box to specify the design layers material type. The reference modulus for this material will automatically be inserted in the Modulus column, and you have following possibility to change this value. In the case where you wish to do a reconstruction based on the existing subgrade you would normally also add new granular layers on the top. Elmod will only calculate design values for the top layer, so you will have to enter both thickness and modulus of the other new layers added, like shown in this example:
The new construction must not have more than 6 layers, with maximum 2 bound layers included.
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Traffic Traffic must be entered as the total passages of all vehicles per year. The number of passages for each vehicle is then entered in the fields below as percentages of this value. These are the values directly used in the deterioration functions defined in the parameter file. Issues regarding multilane roads, equivalence factors, traffic growth etc. must be considered before entering the value. Facilities are available for this through the buttons in the upper right corner of the Traffic frame. For help on this see details in the Elmod 6 Help file. If multiple vehicles have been defined in the parameter file, only the Forecasting facility is available. For airfields you have usually defined a fleet mix of the most critical aircrafts using the facility, as illustrated in this example:
If a normal distribution for the lateral wander of loads was selected in the parameter file, the offset from the centerline to the line where the damage should be evaluated must be entered. Only one distance from the centerline will be evaluated in each design. In this case the critical aircrafts have a tread around 10.000 mm, and the offset should then be around 5.000 mm. You can repeat the design with various offset values to check if the design is sensitive to the change. If the structure has been defined with jointed concrete as top layer, k-values are calculated for both center and joints during the backcalculation. In the design window you will have an option for improving k-values at joints before overlaying:
If you select Subsealing the design calculation will assume the k-values at joints are improved to be the same as the values under slab center.
Click the OK button to commence the design calculation.
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Earlier created designs will not be overwritten, meaning you can view design results in the Plot feature for various traffic input or other changes. The button View Plot is a shortcut to the plot of the design results.
11.2 New Design With this facility you can design a new pavement structure, and get the required thickness of the top layer calculated. No results from the FWD testing or backcalculations are used, so the facility is available even you have no file opened. You still have to create a database as usual.
Select parameter setup Select the parameter file that is valid for your design calculation. You have to select your parameter file, before you can enter material types in the pavement structure. For setting up parameters, see 13. Parameter Setup Add Layers Here you enter your pavement structure from bottom to top. Only the thickness of the top layer can be calculated. First layer to add is the subgrade material. The material’s reference modulus is automatically inserted, and if desired you can change this value. Next you can add the pavement layers with their respective thicknesses (remember to
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enter the thickness to the right of the layer name), and at last the top layer for which the thickness is to be calculated. Use Monte Carlo Simulation Check this to base the design on a Monte Carlo Simulation. You will have the following input window next to the Add Layers window:
This will simulate a variation in the layer moduli according to a logarithmic normal distribution. Each simulation will generate a set of moduli randomly but with probabilities that follow the distribution given by the standard deviation factors. The standard deviation factor is 10 raised to the standard deviation of the logarithms, also called the geometric standard deviation. The number of runs in the simulation, and the standard deviation factor for each layer must be entered. The result for each simulation can be viewed from the Plot facility, and the average and standard deviation will be reported in the Results frame. Select Method Responses under the design loads can be calculated either according to MET (Method of Equivalent Thicknesses) or LET (Linear Elastic Theory). Traffic Please refer to description of input in previous chapter 11.1 Overlay Design. Results When you have clicked Start Design the calculation will be carried out, and the results can be viewed in the Results frame:
If a Monte Carlo simulation has been used, the thickness is given as the average over the number of simulations and with the corresponding standard deviation.
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12. Viewing Results Use the Plot function from the Main menu to get access to any type of results and other data belonging to the currently opened data file. This function allows you to create printed reports, and export data to various file types. The Plot Menu is shown below:
The menu items Backcalculation and Design may be disabled if there are no are no results in the database. Graph Options and Sectioning will be enabled when a graph is displayed. You can, at any time, when you have a data file opened, go to Plots and view any results or deflection data from the database
12.1 Graphs and Tables With the menu items Raw Data, Backcalculation and Design you can select among a collection of graphs. The possibilities are:
When you select graphs for Backcalculation and Design, then the most recent calculation will be displayed immediately. If there are previous calculations or calculations for other sections, you can click Graph Options from the menu and select to view others. No matter which graph is displayed, you can click Graph Options and do various selections and settings for the graph. You can select Tools from the menu to provide choices for printing and exporting graph data. Below you see an example of the measured deflections plotted for the section.
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In the graph each color refers to a geophone, so the upper blue line is all the center deflections for the section. The black line indicates the measured stress level used during testing and refers to the Y- axis on the right hand side. Underneath the graph you have a data table with all the values displayed. In this table you can highlight a selection using the mouse, and following press + C to copy the selection to the clipboard, from which you can paste it into other applications. In the lower right corner you have a window giving statistic for the data. N is number of points included. For Elastic moduli and residual life the statistics are based on a lognormal distribution.
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12.2 Options For any displayed graphics you can click Graph Options. The choices you have in Graph Options will depend of the selected graphics. In the example below, you see the options for the graph “Pavement Response”.
Graph Type refers to how points are plotted along the X-axis. In an “X-Y” graph the points will be plotted according to the correct distances between the points, while the “Line” option plots the points with constant interval between the points. If data are not sorted according to chainage, only “Line” graph can be selected. Data sorted by chainage. If points have not been measured in increasing order, you have the option of viewing the points either sorted or unsorted. Interface. Defines for which layer interface results should be viewed. “1/2” means the responses at bottom of layer 1 and top of layer 2. Design Load and Season. If multiple loads have been chosen for the design, you can select which one to view. The same goes for seasons, which is not displayed in the example because all seasons, for one load has been selected, in the Selection option. Designs gives an overview of all designs carried out for the file, and in the “Check” column you can select which one to view. Show all sections This means that for a file subdivided into sections, you can check this and see the graphics for the complete file. Otherwise you will only have one section at a time.
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12.3 Sectioning
Select Sectioning Start to subdivide the existing section into subsections. The purpose of this is usually to create homogeneous sections, based on the results or the layer structure. With the mouse you can drag the separator lines, by left click on the yellow stationing box, move the mouse and release the left button where you want the line to be positioned. While moving the line you will see the stationing change, reflecting the current position. The Station box will always show the first station to the right of the line, which will be the first station for the section defined. In following example you will see 5 subsections defined, based on the calculated Elastic moduli.
In the Statistics window at the bottom right corner, you will now see 5 tabs with information for each of the 5 defined subsections. These statistics can be printed clicking Reports or just saved and printed later together with other values. If you want to make the current subdivision permanent you now have to select Sectioning Save new sections. This will change all section data in the database for this file including all existing results, to reflect the new sectioning. If you instead select Sectioning Stop nothing will be changed and you are back to normal.
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12.4 Tools Tools provides a range of options for exporting and printing results. Some options may be disabled for some graph types. Most of the options in the menu refer to the currently displayed graph. Export to Excel This opens a window with settings to the export:
Check the data types you want to have exported and click Export. All selected data for the current section will now be transferred to Excel, which will automatically open and organize the data into the sheets Raw data, Backcalculation and Life and Overlay. Notice if you only need data relating to one graph, you can copy the data from the table below the graph. It may be necessary to first open the application to which you want to paste the data from the Clipboard Create Report This will create a report in Microsoft Word based on the data for the current graph. The report may in some case include more data than listed with the graph. The report will automatically open Word, from where it can be printed. Following is an example of a report of calculated E-moduli:
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To print the report, click the printer symbol. To export data click the envelope symbol, which will bring up a window with choices for format of the file. Print Graph This will immediately send the currently displayed graph to the default printer. The graph will be fitted to the printed page. Graph to Clipboard This will copy the current Graph to the Clipboard, from where it can be pasted into other applications like Microsoft Word or Excel. It may be necessary to first open the application to which you want to paste the data from the Clipboard Report parameters This gives the possibility to create a report based on the parameter files used for the current project. A Word document will open with values used for Seasons, Materials and Loads.
12.5 Editing Graph Layout In the Graphics windows you have a range of icons for accessing layout tools for the graph:
No matter which icon you click, you will have the same layout menu, but with different tabs highlighted:
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This facility has its own Help file. If you select the tab “System” you will have access to save layouts, and you will also find possibilities to export the graphics to a picture file (BMP, JPF, WMF) or to the clipboard for insertion into other applications. It is also possible to print the graphics from here.
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13. Parameter Setup A parameter setup contains information that defines the local environmental conditions, traffic characteristics, and material performance characteristics. It is used by the remaining life and overlay design function of Elmod 6. Elmod 6 allows the user to create and tailor parameter files to just about any conditions. It is customary to create a parameter file that is relevant to a specific job, area, environment, set of materials, or network of pavements. These parameter setups can be saved and/or altered to meet specific project requirements, as necessary. The information contained in the parameter file is extremely important and is basically the heart of the design process. Problems with overlay design calculations can often be attributed to the presence of unrealistic or inaccurate information in this file. A list of parameter setups is presented by clicking on the Parameters menu item. A new parameter file can be created by changing parameters in an existing file and saving it under a new name. The new parameter file may be saved for the specific project only and/or as a permanent file made available to all future projects. NOTE: If the changed parameters are saved under the original file name, the original file is overwritten. You can edit all input fields on all tabs before saving. All changes will stay in memory until you press the Save, Delete or Cancel buttons. Save setup will overwrite your existing loaded setup. Save as new Setup will ask for a name for the new setup, and then add this to the list of available setups. Save as permanent Setup will ask for a name of the name setup and add this to the list of available setups for all new created databases. The default setups coming with the installation can not be overwritten or deleted. Delete will permanently remove the loaded setup from the list of available setups. Cancel will return to menu without saving any changes you have made. Export gives the possibility to export the setup to another project database. A Browser will open to allow you to identify which project database to export to.
If a project file is not yet opened, you will select among the list of permanent parameter files. If a project is open, you will select among the parameter setups
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present in the project database. When you create a new database all the permanent parameter setups will be copied to the project database. In this way you can select if you want to modify parameter setups only for the current project, or if you want to make permanent changes. When you have selected which parameter setup to work with all data for the specified setup is loaded into 4 tabs: Seasons , Material Types , Vehicles , and Wheels From the materials option Design Criterias can be setup for each defines material type. When finished, the user can store the parameters under a new filename, or overwrite the existing file.
13.1 Seasons For design purposes, the year may be divided into seasons, with a maximum of 12 seasons. The program calculates moduli corresponding to each season, with respect to seasonal temperature for the asphalt layer and the time elapsed since spring thaw or wet period for the unbound materials (including the subgrade). The remaining life and associated overlay design is then based on the cumulative amount of damage occurring during each season for all design loads using Miner's law.
The user subdivides the year into seasons. For each season the length in weeks is entered, as well as the week to be considered characteristic of that season. The week number is counted from the beginning of the year. The characteristic week is the week in which all the loads of the season would result in the same damage as when the loads are spread out over the season. By subdividing a season Elmod
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6 may be used, through a trial and error process, to accurately determine which week is characteristic. Total number of weeks must add up to 52. The first season will start 1st of January, which means that you would need to divide a season into two seasons if it overlaps this date. If loads are evenly distributed over the year you can click the Even distribution button and Elmod will calculate the accurate percentage values to put into the load per season fields. When you modify seasonal temperatures or factors on the Material Types tab, you have graphics available to see the effect of the settings for each season. From this graphics you also have the possibility of adjusting the characteristic week inside each season.
13.2 Materials When selecting the Material Types tab you get the possibility to see and edit all information in the setup that relates to each of the defined materials.
In the list box to the left you have the current list of materials, and the information on the tab relates to the highlighted item in the list. You can click in the list to view the other material’s properties. Create new material button adds a new material to the list. You will be asked to assign a name for the material (must be unique for the setup), and the new material will be added with properties which are a copy of the currently selected material. You can proceed by changing any values for the new material. Nothing will be saved before you click one of the save buttons on the right hand side, but
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all changes will be stored in memory even if you select other material types to view and edit. Delete current material removes the material from the list. Material Name replicates the highlighted name from the list box. It is not possible to change the name due to reference conflicts. Alternatively you can create a new material with the desired name, and delete the existing material. Material Type can be selected from the dropdown box. The information is used in the design procedures to determine the number of bound layers. Ref. Modulus. The reference modulus of the material is used as the design value in case the material is chosen as the design material. The value is also used to optionally be inserted as seed value in Structures window. Temperature dependant. This defines whether the material modulus is sensitive to temperatures. If it is checked the tab Temperature dependency will be enabled for definition of the modulus/ temperature relationship. The title of the last tab will be Seasonal temperatures for defining temperature variation over the year. If “Temperature dependant” is not checked the last tab will show Seasonal factors for defining modulus variation over the seasons due to other reasons, like frost/thaw periods or rainy seasons affecting the condition of the unbound materials. Fatigue Cracking and Permanent Deformation. This defines which criteria should be used for determining the residual life of the material. The details for selecting the criteria are on the related tabs below. Usually you operate with fatigue cracking for bound materials and permanent deformation for unbound materials. It is possible to have them both switched off, in case it is not desirable to have these materials properties influencing the design calculations. Hatch. Select a pattern to be associated with this material. Click on the pattern to open a window for the possible selections. Min. and Max Modulus. This input can be used to force the backcalculation to produce moduli results within the given range. Be aware that this will influence the moduli calculated for the remaining layers as well.
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Fatigue Cracking and Permanent Deformation
These two tabs are enabled depending on the choice for using Fatigue Cracking relations or Permanent Deformation relations in the checkboxes above the tabs. In the relation N is the traffic and E the modulus of the material. The constants A, B, C and Eo can following be modified in the fields below the equation If the constants reflect a known criteria, then name of the criteria is shown below the constants. If desired another criteria can be selected from this dropdown box, which is prefilled with various criterias developed and used in various regions. The list of items in the dropdown box depends on the choice for using fatigue relations or permanent deformations and the choice for using strain or stress dependency. It is possible (but not necessary) to assign a name to a user specified criteria. Enter the desired constants in the input fields, and the name will change to Unknown criteria. Write the name of the criteria in the drop down field and press Add to list. The list is global, and does not belong to the specific parameter setup. This means changes in the standard list of criterias will be accessible from all projects and parameter setups. Changing the contents of the lists will not affect any design results or parameter setups. Only the values in the white input fields are saved with the setup. On the Fatigue Cracking tab you can select if Longitudinal or Transversal responses should be used in the criteria. The longitudinal responses are the most critical. Define the materials Design life. The design life together with the yearly amount of traffic determines the number of axle passages in the criteria functions. Notice
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that the required design life with respect to different types of deterioration (as well as for different types of materials) may be different. By clicking View the relation will be shown graphically.
Temperature dependency This tab is enabled if the checkbox Temperature dependent is checked.
Temperature dependency is usually used with bitumen bound materials, and allows the asphalt modulus to be corrected to a reference temperature. This is important to do before any design because the temperature usually vary a lot over the day and over the year, and because the stiffness of the bitumen is very sensitive to the temperature. The design procedure first converts the asphalt modulus from asphalt temperature recorded during testing to the modulus at the reference temperature as entered in the Ref. Temperature input field. Next this modulus at reference temperature is used to calculate the seasonal moduli, according to the temperature given for each season . On this tab you can choose between 3 methods for temperature correction: Factors This will refer to a table created, which assigns a factor to each temperature in the temperature range. In the dropdown box you can select which table should apply to the current material. To create and edit these tables see the Elmod 6 built-in help. Semi–logarithmic If the dependency can be fitted to a logarithmic relation, you have possibility to define the equation:
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Notice that the range for which the equations is valid must be positive. When temperatures exceed the range Elmod will use the from or to value to calculate the correction factor. Exponential If the dependency can be fitted to an exponential relation, you have possibility to define the equation:
When temperatures exceed the range Elmod will use the from or to value to calculate the correction factor. View. Clicking this button brings up a window with a graphic presentation of the temperature-modulus correction.
Seasonal Temperatures or Seasonal Factors. If the material has been defined to be temperature dependant you can set the seasonal temperatures:
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The purpose is to define each season’s design temperature. The seasonal design temperature should be fitted to a value that will result in a damage representing the average over the season. The seasonal temperatures can either be set manually or calculated by a sinusoidal relationship between time over year and asphalt temperature. If the material has not been defined to be temperature dependant you can set the seasonal factors:
For materials that are not temperature sensitive the Elmod 6 user has the opportunity to consider the (probable) springtime or wet season weakening of any, or all, of the unbound layers in the pavement section. The purpose of the facility is then to determine the factor used for each season. A factor of 1 will be the reference condition, and the seasonal modulus of each season is then calculated as the seasonal factor multiplied with the modulus at the reference condition. The modulus at reference condition is calculated first as the backcalculated modulus divided by the factor belonging to the week where the FWD measurement took place. Interpolation between the factors entered for the seasons and the characteristic weeks will determine the factor belonging to the week of FWD testing. As an alternative to enter the factors manually, they can be set according to either a sinusoidal or an exponential relation View. Clicking this button brings up a window with a graphic presentation of the temperature-modulus correction.
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13.3 Vehicles and Wheels The design traffic and load characteristics are defined on the tabs Vehicles and Wheels. In the design procedures Elmod will include all defined vehicles, and for each vehicle Elmod will include the wheels specified on the Vehicle tab. It is possible to define a traffic mix of up to 24 vehicle types including a total of up 100 wheel types. Often ESALs is used to characterize the design traffic. In this case only 1 vehicle including 1 standard wheel is going to be used. However, it is preferable to use the best approximation to the real traffic mix of loads, as the derivation of the equivalent standard loads depends on the design criteria (transfer functions), and may be different for different layers.
In the list to the left, you will see those vehicles that are included. You can add a new vehicle by clicking Create new vehicle. If the option Copy current is chosen you will be asked for a name of the new vehicle, and this will be created with a copy of the data for the current one. Creating a new vehicle this way will not influence the choices for selecting wheels. The list of available wheels will be the same, and if you need to attach a wheel which is not in the list of wheels on the Wheel tab, you will have to shift to this tab and add a new wheel. If you define a new aircraft, you have the possibility to retrieve all necessary information from the aircraft database. Select the option Aircraft list and click Create new vehicle. This opens a window for selecting the aircraft. Select one and click OK. Elmod will now load the information required in both the Vehicle tab and the Wheel tab.
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Click Delete current vehicle to remove this from the list of vehicles. No changes will happen to the list of wheels on the Wheel tab. The example above shows input value for operating with an ESAL as design load. Pass to coverage or normal distribution defines which method should be used to reduce the traffic numbers due to the lateral distribution of loads. For roads the reduction is usually not considered, meaning all wheels loads are in the same line. In this case select Pass to coverage and on the Wheels tab, set the factors to 1. For evaluation of Airport pavements the lateral distribution of the aircraft loads will be important. This may be considered by entering Pass to coverage ratios for rigid and flexible pavements, or by using a normal distribution of the aircraft loads. In this case the imported wheel base is used, whereas the user must provide a value for the standard deviation of the lateral position of the particular aircraft at the facility to be evaluated. A default value is provided by the program, but the actual lateral wander will vary considerably, for example between a runway and a taxiway. When a normal distribution is used for the overlay design, the stresses and strains will be calculated at one line, given by the offset from the centerline (input in the Overlay Design screen) with the wheel at 10 points of the normal distribution, each with a probability of occurrence relating to normal distribution of the traffic. The damage at the offset line is summed using Miner’s law. Vehicle name. This replicates the highlighted name from the list box. It is not possible to change the name due to reference conflicts. Alternatively you can create a new vehicle with the desired name, and delete the existing vehicle. Total weight is the complete mass to be distributed over the axles and wheels. In case of ESAL’s it should be the weight corresponding to the definition of the ESAL. Dynamic Ratio defines a factor to be multiplied on the load. A factor of 1.2 means the load will be increased by 20 % for design purposes. Standard deviation relates to the lateral normal distribution of traffic as described above. Wheel name. Here you enter each axle or wheel belonging to the vehicle, and for which responses should be calculated in the design procedure. Clicking in the input fields brings up the selection of defined wheels from the Wheels tab. This means the selection of wheels must be defined on the Wheels tab before you can connect them to a vehicle. % of load indicates how big part of the total weight applies to the wheel (or set of wheels). Usually you have a set of wheels on the axles symmetrical positioned to the center line of the vehicle. The percentage of load should then apply to the
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total load of both sets of wheels. On the Wheels tab you can see exactly how many wheels are included in the definition. Load on each tire if further calculated to the right of the input field, to avoid any misunderstandings.
In the list to the left you can see the defined wheels. Only wheels that are referred to from the Vehicle tab are included in the design. Select the wheel in the list for which you want to see or to edit properties. You can create a new wheel as a copy of the current by clicking Create new wheel. You will be asked for a name of the wheel, which must be unique for the setup. Click Delete current wheel to remove a wheel from list. You cannot delete a wheel if it is referred to from the Vehicle tab. Wheel name. This replicates the highlighted name from the list box. It is not possible to change the name due to reference conflicts. Alternatively you can create a new wheel with the desired name, and delete the existing wheel. Pass to coverage defines the factors to be used for respectively flexible and rigid pavements. For aircraft setups where data from the aircraft database are included, it is recommended to use the normal distribution option (see above). If you use the Pass to coverage values in this case be aware of that these only apply to the critical gear, for the other gears which may be defined the fields should be left blank. Centerline wheel. Check the field if there is no symmetrical positioned wheel (like the nose wheel for an aircraft). You will see on the graphics exactly how it is defined. Wheel Configuration. You can select between 6 configurations of tires making up the complete wheel or gear. The graphics will show the outline of each.
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Tire pressure. Enter the tire pressure for the wheel. Wheel distance. Enter the distance between the centerlines of dual wheel configurations. Axle distance. Enter the distance between the axles for tandem and tridem wheel configurations. Tread. This defines the distance between the wheel sets positioned symmetrically to the center line. This is used together with Offset to calculate the distance between the each line of traffic from the normal distribution and to the line for which responses are calculated. Se more about using Normal distribution above and the offset value entered in the Overlay Design window.
Below is shown input example for a setup with a fleet mix of four aircrafts:
And on top of next page, the related Wheel tab information:
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