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Final Report - Minnesota Local Road Research Board

1. sese 6 Figure 2 2 New GPR vehicle antenna mount seen rennen nennen nene 7 Figure2 3 Mn Trunk Highway 1 test site location esee 7 Figure 2 4 Mn Trunk Highway 96 GPS GPR mapping test 9 Figure 2 5 TH 96 GPS GPR data point 0 eee cseeseenseceseceseceaeceseeeeeeseeeeeeseneeeaeeeaeeeaaeenaees 10 Figure 2 6 TH 96 Sample Report tete e Ue E tpe He EO te be i ibt oce o 11 Figure 2 7 MnDOT Basemap TH 96 Project Location eee 12 Figure 2 8 MnDOT Basemap TH 96 Project Detail eese 12 CHAPTER 1 INTRODUCTION 11 BACKGROUND Mn DOT districts are increasingly requesting Ground Penetrating Radar GPR investigations of pavement layer thickness and other subsurface investigations Research completed to date at Mn DOT concerning GPR has focused on procurement of radar equipment defining Mn DOT GPR operational methods performing GPR field surveys and development of improved methods of layer analysis The ground penetrating radar equipment currently owned by Mn DOT uses a vehicle distance measurement Instrument DMI and written notes taken by the operator to define survey limits and report on features and or defects found Although distance measurement instruments are commonly used at Mn DOT to record positions along trunk highways the level of accuracy using reference post data provides insufficient detail to precisely map the route of the radar survey vehicle and the featur
2. Click the Save as type drop down arrow and click the format in which to create the new point features Navigate to the folder in which you want to store the new features Type a name for the new data source Click Save Set any Advanced Geometry Options and ArcSDE configuration keywords as necessary Click OK 4 3 02 Project Callout Text Box Adding text with a callout box and leader line consists of the following steps Click the Callout button ad on the Draw toolbar Click a project point for the leader line and drag and release the mouse pointer where you want the callout and text to be placed in the image below the start point is the yellow dot r Type the text string June 11 2010 GPR OPERATION MANUAL 1 1 4 3 03 HYPERLINKS Hyperlinks let you provide additional information about the features to people who will be using your maps with ArcMap When you click a feature with the Hyperlink tool a document or file is launched using the application with which that file type is currently associated Accessing a feature s hyperlink consists of the following steps a Make sure the layer containing the feature for which you want to access a hyperlink is checked on visible in the table of contents b Click the Hyperlink tool Any visible features in the map that have hyperlinks defined are drawn in blue the default color or outlined in blue in the case of polygons When you are over a feature for which a hyperlink exis
3. Minnesota Department of Transportation Incorporating GPS and Mapping RESEARCH Capability into SERVICES Ground Penetrating Radar GPR ce Operations for Pavement Thickness Policy Analysis Research amp Evaluations Innovation BUCO CITUR cei Mn ROAD Office of Materials June 2010 Research Project Final Report 42010 37 Technical Report Documentation Page 1 Report No 2 3 Recipients Accession No MN RC 2010 37 4 Title and Subtitle 5 Report Date June 2010 Incorporating GPS and Mapping Capability into Ground Penetrating Radar GPR Operations for Pavement Thickness Evaluations 7 Author s 8 Performing Organization Report No Matthew A Lebens P E 9 Performing Organization Name and Address 10 Project Task Work Unit No Minnesota Department of Transportation Office of Materials and Road Research 11 Contract C or Grant G No 1400 Gervais Avenue c GPSGPR Maplewood MN 55109 2403 12 Sponsoring Organization Name and Address 13 Type of Report and Period Covered Minnesota Department of Transportation Final Report Research Services Section 14 Sponsoring Agency Code 395 John Ireland Boulevard MS 330 St Paul MN 55155 1899 15 Supplementary Notes http www Irrb org PDF 201037 pdf 16 Abstract Limit 250 words Ground Penetrating Radar GPR investigations performed by Mn DOT of pavements and other subsurface features have been limited by an inefficient and poorly documented GPR survey proces
4. 6591 288 6606 872 6668 371 6726 871 6887 87 7079 369 7447 2 7630 865 7918 697 8226 196 8914 192 9209 024 9325 357 9459 772 9470 439 9594 105 9610 855 9658 188 9776 354 10034 69 10216 52 10327 6 10345 18 11651 93 11665 09 11847 68 11970 51 11981 01 12215 42 12353 84 12684 09 13596 17 14028 41 14046 91 14098 5 14114 83 14201 58 14211 5 dist from power line crossing 0 00 540 4 712 2 864 7 1343 2 1387 7 1400 6 1498 9 1515 5 1584 4 1925 6 2050 5 2066 1 2127 6 2186 1 2347 1 2538 6 2906 4 3090 1 3377 9 3685 4 4373 4 4668 2 4784 6 4919 0 4929 6 5053 3 5070 1 5117 4 5235 6 5493 9 5675 7 5786 8 5804 4 7111 1 7124 3 7306 9 7429 7 7440 2 7674 6 7813 0 8143 3 9055 4 9487 6 9506 1 9557 7 9574 0 9660 8 9670 7 start WBLTVOIDPICKS EBLTVOIDPICKS EBRTVOIDPICKS WBLTVOIDPICKS WBRTVOIDPICKS EBLTVOIDPICKS WBRTVOIDPICKS EBRTVOIDPICKS EBRTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS EBRTVOIDPICKS EBRTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS WBRTVOIDPICKS WBRTVOIDPICKS EBLTVOIDPICKS EBLTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS WBLTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS EBRTVOIDPICKS WBLTVOIDPICKS WBRTVOIDPICKS WBRTVOIDPICKS WBLTVOIDPICKS WBRTVOIDPICKS EBRTVOIDPICKS WBLTVOIDPICKS EBRTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS EBLTVOIDPICKS WBLTVOIDPICKS EBLTVOIDPICKS EBLTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS EBRTVOIDPI
5. can be modified by the viewer Included in this block is the menu that controls the settings for the summary statistics and the plots provided in blocks 4 and 5 d Summary Statistics Summary statistics of the data between the limiting mileposts are shown as a table format The statistics include average standard deviation minimum and maximum values and the limiting mileposts are the x limits in 3rd block e Plots The data is plotted and shown in this block Using the menu in the 3rd block the viewer can choose to plot different data thickness cross slope or rut depth The horizontal and vertical axes can be modified for zooming in and out 5 2 02 DATA The data sheet consists of the actual data including mileposts thicknesses and drilling data placed under the corresponding columns and lanes Mileposts and the thicknesses can be copied from the excel files exported from Access and pasted into this spreadsheet 5 3 GIS REPORT 5 3 01 MAP TEMPLATE If the map is part of a series you might have a template to work from or you might create a new template for the series Map templates make it easy to produce maps that conform to a standard and they save time by letting you do the layout work for all the maps in the series at once June 11 2010 GPR OPERATION MANUAL 1 1 5 3 02 MAP PRINTING In the web based GIS map as shown above there is a pull down menu in the toolbox at the upper left The down arrow should be clicked to select na
6. The software allows the user to view the amplitude of the reflected waves in either stacked waveform or color coded display as shown in Figure 5 The horizontal axis at the top shows the traveling distance of the vehicle while the vertical axis on the left shows the two way travel time of the radar wave The color coded display mode is preferred for data processing since it is easier to understand and more convenient to use 3 2 PAVEMENT LAYER THICKNESS 3 2 01 CALIBRATION FILE GENERATION Each raw calibration file dzt is processed using the Calibration file generation tool in RADAN The default extension on the output from the Calibration Tool is czt The calibration generation tool reorganizes input data scans performs some scan stacking and overwrites the last 6 samples of each output scan with specific amplitude and height information Choose 4105HR for the 2 GHz and 4108HR for the 1 GHz Save the CZT file with a name that consists of the calibration date If more than one calibration files exist add the letter at the end of the date file name Save CZT file to the folder called Horn Calibration 3 2 02 AUTO LOAD CALIBRATION FILE RADAN will search for a CZT file in the Current folder selection Check to make sure that the calibration file displayed is correct and if not uncheck auto load calibration file click browse to pick the appropriate calibration file and click finish The data file will scroll rapidly and it
7. Trimble GPS Pathfinder ProXRT receiver Input None Output NMEA Output Baud Rate 9600 Output Message GGA disable all others Output Rate ASAP GPS Configuration see Trimble manual Position Rate 5 Hz DGPS Configuration see Trimble manual Source OmniStar Ups Ao ao oe GPS data from the Trimble GPS Pathfinder ProXRT receiver is logged using the Acumen Data Logger for GPR The settings on the Acumen Data Logger shipped with the SIR 20 system are factory preset to match the baud rate of the SIR 20 Tough book computer serial communication port 115 200 bps Acumen data logger settings are adjusted using the HyperTerminal communication utility by specifying the following parameters a Bits per second 115200 b Data Bits 8 c Parity None d Stop Bits 1 e Flow control Hardware The mandatory reference is Acumen Data Logger and Trimble AG132 GPS SIR 20 System Settings and User Notes June 11 2010 GPR OPERATION MANUAL 1 1 2 2 03 DMI GSSI provides the Model 630B High Resolution Distance Measuring Instrument DMI with the RoadScan system Model 630B Distance Measuring Instrument DMI represents the state of the art in high speed high accuracy survey control The 630B is designed to be used on the rear wheel of a vehicle The mandatory reference is Model 630B Distance Measuring Instrument DMI Assembly Guide June 11 2010 GPR OPERATION MANUAL 1 1 2 3 DATA COLLECTION 2 3 01 PROJECT RECORDS The amo
8. and browse the data that the organization or agency has made available A layer based on an ArcIMS feature class works the same as any other feature layer A Feature service layer acts like a group layer as a container layer for child layers These child layers are ArcIMS Feature Classes which reference individual feature classes residing on an ArcIMS server June 11 2010 GPR OPERATION MANUAL 1 1 An ArcGIS Server map service provides mapping data associated with a single data frame of an ArcGIS map document mxd or pmf that is being served through ArcGIS Server You can connect to an ArcGIS Server map service over the Internet or over a local area network LAN 4 3 CONVERSION 4 3 01 PROJECT POINT LAYER Creating a point feature class from x y coordinates exported from GPR header file consists of the following steps a b ga r pete ue Right click a table in the ArcCatalog tree that has columns containing coordinates point to Create Feature Class and click From XY Table Click the X Field drop down arrow and click the name of the column that contains the x coordinates Click the Y Field drop down arrow and click the name of the column that contains the y coordinates If appropriate click the Z Field drop down arrow and click the name of the column that contains the z coordinates Click Spatial Reference of Input Coordinates and define the coordinate system for the input values as necessary Click the Browse button
9. the dialog window The Generate New ASCII File option should be checked and OK clicked The target picking options should be specified prior to picking All of the user options available in Interactive Interpretation are accessed first by moving the mouse cursor so that it is within the Interactive Interpretation data window upper pane then pressing the right mouse button Clicking on the Target Options menu item from the Main Menu opens up a list box containing the names and properties of all of the targets Targets are added by clicking M Target The new target properties are edited by placing the mouse cursor over the target name and double clicking The following properties should be used June 11 2010 GPR OPERATION MANUAL 1 1 Picking Criteria Positive Peak Velocity Calc User specified or Core Data a Name Steel Bar b Color White c Size 5 d Diameter 0 e f The target points can be picked either using single point or EZ Tracker The pick locations depths and reflection amplitudes are stored in an ASCII file lay when the user selects the Save Changes option An ASCII file can be opened and edited many times 3 3 04 EXPORT Project information are stored in the header file and exported into tabular data that contains geographic locations in the form of x y coordinates to your map The GPR results can be directly exported to KML files under the conditions that the GPS coordinate systems have be enabl
10. to determine suitable Global Positioning System GPS equipment for the Mn DOT GPR vehicle and hand cart The goal was to acquire a GPS system that would provide an acceptable level of GPS accuracy while functioning during GPR data collection at highway speeds The GPS data output format also had to be compatible with the Radar equipment owned by Mn DOT It was determined that the best GPS system for the GPR needs would be a Trimble ProXRT receiver with GLONASS capability The ProXRT is commonly used in Mobile GPS for GPR operations by other users It allows a 1 Hz re positioning rate with uncorrected sub meter accuracy Higher positional accuracy can be obtained with post processing or real time with a correction signal To control the mobile receiver a JUNO handheld device was acquired along with processing software and vehicle mounting hardware for the GPS equipment In July 2009 the GPS equipment specified was purchased from Frontier Precision INC of Bloomington MN This is a company that had previously supplied Mn DOT with Trimble equipment and had a good track record of expertise and support In fall of 2009 training was provided by Frontier Precision at the Maplewood research lab to familiarize the employees working with the radar equipment with the GPS system 2 3 STANDARDIZED GPR MAPPING AND REPORTING To complete the standardized mapping and reporting tasks of this project the consultant firm American Engineering Testing AET was c
11. 0 246 7 4 0 265 8 3 0 265 7 8 0 284 8 5 0 284 8 5 0 303 10 6 0 303 8 3 0 322 9 7 0 322 8 6 0 341 7 2 0 341 7 3 0 360 6 1 0 360 7 6 0 379 6 5 0 379 8 2 0 398 6 9 0 398 8 7 0 417 6 1 0 417 8 5 0 436 6 5 0 436 9 1 0 455 6 3 0 455 8 7 0 474 7 6 0 474 10 8 0 492 7 0 0 492 10 0 0 511 7 7 0 511 7 5 0 530 6 8 0 530 TA 0 549 7 1 0 549 7 4 0 568 6 4 0 568 8 3 0 587 7 5 0 587 7 0 0 606 8 2 0 606 7 5 0 625 7 4 0 625 8 4 0 644 7 7 0 644 9 2 0 663 7 3 0 663 8 1 0 682 7 6 0 682 7 7 0 701 7 3 0 701 7 7 0 720 7 7 0 720 7 4 0 739 8 3 0 739 8 0 0 758 7 8 0 758 8 7 0 777 7 0 0 777 7 4 0 795 6 9 0 796 6 6 0 814 6 7 0 814 6 6 0 833 7 4 0 833 6 8 0 852 5 9 0 852 7 0 0 871 6 8 0 871 6 9 0 890 7 3 0 890 6 5 0 909 7 5 0 909 6 2 0 928 9 1 0 928 9 1 0 947 8 2 0 947 10 3 0 966 7 6 0 966 9 8 0 985 7 8 0 985 9 0 1 004 7 6 1 004 8 0 1 023 6 6 1 023 7 7 1 042 6 6 1 042 7 5 1 061 6 9 1 061 8 0 1 080 7 3 1 080 8 2 1 098 8 8 1 099 8 4 1 447 14 0 1 117 15 4 1 136 16 1 1 136 21 2 1 155 16 9 1 155 14 2 1 174 8 7 1 174 18 1 1 193 8 3 1 193 15 6 1 212 8 3 1 212 16 7 1 231 11 3 1 231 13 5 1 250 13 3 1 250 11 9 1 269 12 5 1 269 12 4 1 288 11 2 1 288 12 7 1 307 11 3 1 307 12 7 21 APPENDIX C GPR OPERATIONS MANUAL 22 June 11 2010 GPR OPERATION MANUAL 1 1 CHAPTER 1 GENERAL 1 1 INTRODUCTION 1 1 01 PURPOSE The Minnesota Department of Transportation Mn DOT GPR Operation Manual provides an overview of the GPR data collecting with a GPS extension a
12. 0 GHz and 2 0 GHz Table 2 2 Mn DOT GPR Antenna Air Coupled Ground Coupled 100 MHz Model 3207 Range 500ns Depth of penetration ft 3 15 15 8 3 Samples per Scan 512 Resolution 16 bits Number of gain pts 5 Vertical High Pass Filter 25 MHz Vertical Low Pass Filter 300MHz Scans per second 16 100 500 Transmit Rate 100 kHz KHz 100 kHz 100 kHz 50kHz The approximate depths of penetration for each of these antennas are given in Table 2 2 In general the depth of penetration is inversely proportional to the antenna transmission speed In addition Mn DOT maintains a vehicle totally dedicated to GPR data collection that includes an independent power source GPS data collection electronic DMI device GPS unit and a Video camera Also for off road projects a baby buggy has been modified for GPR data collection which includes a battery power source and survey wheel The SIR 20 is a high speed powerful multi channel ground penetrating radar system that is ideal for a wide variety of applications With different installations two same or different antennas can be operated simultaneously with one SIR 20 The maximum number of antennas that can be operated by one vehicle and two SIR 20 processors is four Two DMI units are required for four antennas one for controlling data acquisition and one for synchronizing two SIR 20 processors References that should be used are a SIR System 20 Manua
13. CKS WBRTVOIDPICKS EBLTVOIDPICKS 18 2 702 2 830 2 856 2 859 2 898 2 939 2 942 3 127 3 127 3 130 3 166 3 196 14267 5 14940 91 15080 49 15098 16 15303 74 15515 49 15532 07 16508 98 16511 4 16526 82 16713 9 16874 73 9726 7 10400 1 10539 7 10557 4 10762 9 10974 7 10991 3 11968 2 11970 6 11986 0 12173 1 12333 9 WBRTVOIDPICKS WBRTVOIDPICKS WBRTVOIDPICKS EBRTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS WBLTVOIDPICKS EBRTVOIDPICKS WBRTVOIDPICKS WBRTVOIDPICKS 19 APPENDIX B TH96 GPS GPR EXAMPLE REPORT Ground Penetrating Radar Pavement Thickness Survey Washington County Control Section 8211 SR 001 MP 0 368 to 10 2 1 368 2 368 3 368 4 368 5 368 6 368 7 368 8 368 9 368 Milepost D Ground Penetrating Radar Pavement Thickness Survey Washington County Control Section 8211 SR 001 MP 0 368 to 10 2 1 368 2 368 3 368 4 368 5 368 6 368 7 368 8 368 9 368 Milepost RI 20 L1 R1 Mi HMA Thickness PCC Thickness CrossSlope Rut Depth HMA Thickness PCC Thickness Cross Slope Rut Depth ilepost Milepost in in in in in in 0 019 8 8 0 019 8 9 0 038 8 1 0 038 7 2 0 057 10 2 0 057 6 8 0 076 9 6 0 076 7 0 0 095 9 2 0 095 8 4 0 114 8 5 0 114 10 9 0 133 7 7 0 133 8 3 0 152 8 5 0 152 9 6 0 170 7 0 0 171 9 3 0 189 7 6 0 189 8 0 0 208 7 1 0 208 9 7 0 227 7 6 0 227 7 7 0 246 7 4
14. Customize Click Directories tab e Click the Source button for a window pop up with a list of folders that are on your computer Find the folder created in the previous section and click the picture of the little folder to open it Then click OK f Click the Output button to select the same folder as Source and create a subdirectory called Output under the source folder Source and Output folders should be separated because the SIR 20 will store different parts of data in different places It does this so that parts of data that won t get overwritten by accident like project info files are protected in the Source folder while the system stores other files in the Output processed data June 11 2010 GPR OPERATION MANUAL 1 1 g Click the Linear Units tab Click the down arrow for a pull down menu list after Vertical button to select INCH Click the down arrow for a pull down menu list after Horizontal button to select FOOT if the project length is less than 5 miles or select MILE if the project length is greater than 5 miles Click the down arrow for a pull down menu list after GPS Units button to select Lat Long h Click the SIRVEYOR tab to configure the GPS Click the down arrow for a pull down menu list after GPS button to select SDR Logger Click the down arrow for a pull down menu list after Port button to select COM1 Click the down arrow for a pull down menu list after Baud rate button to s
15. If the noise reduction filter has been installed in the antenna 4105NR Custom filter should be applied instead by selecting the filter which corresponds to your 4105NR s serial number Low Pass wets TT trace will a High Pass MHz 4105 SNITT 4105 SN122 d Save Macro After assigning the correct parameters for data collection click the Antenna Calibration File button followed by the Next button 2 3 04 CALIBRATION The Bumper Jump Antenna Calibration file CZT is crucial to Horn antenna processing A4 x 4 foot 1 2 x 1 2 m minimum size sheet of metal is used for the antenna calibration This metal plate should be clean and smooth A Bumper Jump file will be collected at the beginning of each day s data collection If the filed work lasts longer than 6 hours an additional one will be collected at the end of the day as well The calibration file should have the same system parameter setup as data files defined in Section 2 3 03 June 11 2010 GPR OPERATION MANUAL 1 1 2 3 05 FIELD WORK The field work is performed by a two person crew that consists of a designated driver and a GPR operator The GPS receiver is attached at the center of GPR antenna mounted to the vehicle front bumper or the GPR buggy Manually inserted markers are needed to assist in minimizing the error due to the starting offset in the data The operator should take notes of what the markers are representing As many
16. PUN DGN B 8211PE UTM PUN DGN C telIPC UTM PAN DGN O frond RGB Wt Band BB Geen Bod 2 Me bed I B fad RG BOrlBtRteSH HD Jeej bees v GP R EAR z zz f Aid JMB z u Av amp se 2 514839 061 4991522216 Feet Figure 2 5 TH 96 GPS GPR data point For the TH96 test project the pavement thickness was the primary focus of study A standard method to report this type of GPR survey was developed The standard report contains general project information a statistical thickness and length summary and both graphical and listing representations of pavement thickness The inputting and reporting spreadsheets developed with this project can be adapted to any future GPR project They were developed in a user friendly checkbox format An example of the GPR reporting input form is shown in figure 2 6 A summary pavement thickness report for the TH96 test project is attached in Appendix B The process for mapping and reporting the GPR data was documented and provided to Mn DOT for use in creating the GPR user manual required as part of this project 10 SUMMARY OF PAVEMENT SURVEY COUNTY Wahington Test Date Date PROJECT NO 50204 3 8 2010 6 11 10 PFN 1234 5 STATE ROAD TH 96 MILEPOST LIMITS SLMP 0 368 to PAVEMENT TYPE Legend F Flexible R Rigid B Composite HMA PCC and W Composite PCC HMA SUMMARY STATISTICS amp PLOT SETTINGS Please use the menu in this block to modify t
17. and base layer thickness with GPS X Y coordinates photos of the pavement and GPR filename information The mapping layers generated are presented in ArcGIS format and utilize the Mn DOT GIS base map and or county highway GIS maps The mapping capability developed is in a format allowing output into a written report which will include a printed Minnesota ArcGIS project details map Mn DOT Web based interactive basemap is used to display the GPR project information and test results if the size of the GPR shape file is less 20 MB Custom ArcGIS toolbars developed in the basemap provide point and click data automation enabling analysts and scientists to easily navigate through GPR project layers and state highways while hyperlinked features provide real time access to project reports and GPR data June 11 2010 GPR OPERATION MANUAL 1 1 4 2 CONVERSION 4 2 01 FILE ORGNIZATION GPR Project information in tabular format are supplemented or merged with the highway project information into a project file The GPR supporting files include the followings a Report files b Results files c Core picture files 4 2 02 IMPORT Coma delimited files csv are preferred for importing GPR results files into ArcGIS to create the shape files Both project files and results files can be converted into cvs files using MS Excel During importing the MnDOT projection is needed to be specified as follows a Group UTM Nad 1983 b Name NAD 1983 UTM Zon
18. ating Radar GPR operations for pavement thickness evaluations Final Report Submitted by Office of Materials Minnesota Department of Transportation Prepared by Matthew A Lebens MN DOT OFFICE OF MATERIALS AND ROAD RESEARCH 1400 Gervais Avenue Maplewood Minnesota 55109 2044 June 2010 ACKNOWLEDGEMENTS The author would like to express appreciation to the Minnesota Department of Transportation for their support of this research Special thanks are offered to Shongtao Dai of the Office of Materials for his technical support and guidance and to Gary Wallner of the Office of Pavement Management for technical assistance and collection of the data presented herein TABLE OF CONTENTS CHAPTER 1 INTRODUCTION erre hie tre et P POR DRE RE HR Ee ut edd 4 LT BACKGROUND sonaa Ee e a eee ert rete tales 4 1 223 OBJECTIVE seen r a a E S ERROREM ER UE 5 3 SCOPB eien 5 CHAPTER 2 PROJECT ACCOMPLISHMENTS senes 6 2 1 GPR VEHICLE ANTENNA FRONT MOUNT SYSTEM 6 2 2 INCORPORATING GPS CAPABILITY IN TO THE GPR SYSTEM 8 2 3 STANDARDIZED GPR MAPPING AND REPORTING 8 2 4 DEVELOPMENT OF GPR MANUAL eere ener 13 CHAPTER 3 PROJECT SUMMARY 4 eerte 13 APPENDICES APPENDIX A TEST PROJECT FOR VEHICLE FRONT MOUNT APPENDIX B TH96 GPS GPR EXAMPLE REPORT APPENDIX C GPR OPERATIONS MANUAL LIST OF FIGURES Figure 2 1 Previous vehicle GPR antenna mount
19. avement Survey Ww Pathway Services Inc Digital Images Ver 9 56 MnDOT Image Help m Image Location Data 01 05 19 19 Rec 15926Set 190 Dist 4534 8 ft assgRP LJ 400m h Lat 48 1950874 Lon 97 1241760 Heading 86 6 Date 07 30 2008 Time 10 26 Road Name M1 Dir From NO DAK MINN Surf Frfpost 0 000 Trfpost 0 820 IRI Le 114 IRI R e 125 RUT L e 0 19 RUT R e 0 14 Begin Eastbound pavement scans Milepost 0 86 directly under the overhead utility line crossing Pathway ervices Inc Digital Images Ver 9 56 MnDOT Image Help m Image Location Data 01 08 28 02 Rec 15929Set 190 Dist 1606 6 ft 3 559 RP LJ 59 0 m h Lat 48 1951790 Lon 97 0644455 Heading 89 5 Date 07 30 2008 Time 10 29 Road_Name M1 Dirl From 3 3 MI E E CL Surf BEG 94 THIN Frfpost 3 255 Trfpost 4 000 IRI Le 118 IRI R e 125 RUT Le 0 20 RUT R e 0 19 End Eastbound pavement scans Centerline of Co Rd 17 approx Milepost 3 56 17 milepost 0 86 0 962 0 995 1 024 1 114 1 123 1 125 1 144 1 147 1 160 1 225 1 248 1 251 1 263 1 274 1 305 1 341 1 410 1 445 1 500 1 558 1 688 1 744 1 766 1 792 1 794 1 817 1 820 1 829 1 852 1 901 1 935 1 956 1 959 2 207 2 209 2 244 2 267 2 269 2 314 2 340 2 402 2 575 2 657 2 660 2 670 2 673 2 690 2 692 Th1 Voids visible in Radar Data 4540 8 5081 214 5252 963 5405 462 5883 959 5928 459 5941 375 6039 708 6056 291 6125 208 6466 372
20. ble GPS equipment configuring the GPR system to incorporate the GPS data and developing a standardized GPS data transfer and collection process Developing an improved standardized GPR project mapping capability in ArcGIS format Developing a uniform comprehensive data reporting format for GPR projects that includes GPS coordinate data Mapping of project locations and detailed mapping of specific underground investigations and Standardized layer thickness data Developing a GPR user operating manual which will compile operating instructions for GPR amp GPS equipment mapping software and reporting examples developed in other tasks of this project Preparation of a final report describing field testing of the new dual antenna and GPS system and results of the subsequent analysis documentation on the GPS and mapping development recommended GPR standardized reports to accompany the new equipment enhancements and final recommendations on full implementation of GPR equipment and standardized reports CHAPTER 2 PROJECT ACCOMPLISHMENTS 2 1 GPR VEHICLE ANTENNA FRONT MOUNT SYSTEM In December of 2008 a literature and internet search was performed to determine the best system for a vehicle mount that would allow dual antenna GPR data collection and be safer and more stable than the in house system built during the GPR research phase Mn DOT was informed that a new vehicle mount system had recently been developed by the manufacturer of Mn DOT
21. contain the essential operating instructions for GPR amp GPS equipment field mapping software and reporting methods and examples The version 1 1 GPR user manual was completed by AET and transferred to Mn DOT in June 2010 It is considered complete for purposes of this project but may be updated and improved upon as future changes to the GPR operations or reporting needs develop It is intended that at some point the manual created with this project will be incorporated into the Mn DOT standard manual system therefore the format of the GPR manual follows the typical Mn DOT manual format The June 2010 GPR Manual version 1 1 is attached in appendix C CHAPTER 3 PROJECT SUMMARY A safer more robust system for GPR survey operations using either single or dual air coupled antennas was accomplished with this project The simultaneous use of dual GPR antennas provides redundancy in data collection and a comparison tool to improve accuracy and completeness of the survey results Incorporating GPS into GPR pavement management surveys has been requested by Mn DOT soils engineers and others and is important for effective data sharing The accurate coordinate data obtained with the GPS system acquired for this project will be used to apply ArcGIS mapping and project information and history capability to the GPR reports The development of a user friendly standardized format for GPR data reporting at Mn DOT will also be a useful improvement The GPS p
22. d to select project and then just to the right is upload shapefile The shape files are uploaded using the following steps Browse for the shapefile files created in ArcGIS 9 2 Load all four of the necessary files shp shx dbf and prj Name your new map layer Press Submit and if the points are valid they should show up as an uploaded layer e Change point properties in the symbolize layer box Rome June 11 2010 GPR OPERATION MANUAL 1 1 CHAPTER 5 REPORTING 5 1 INTRODUCTION The reporting is in a format allowing output into a written report which will include a printed Minnesota ArcGIS project details map 5 2 DATA REPORT A spreadsheet reporting the layer thickness should be prepared and sent electronically to the requestor The spreadsheet contains 2 worksheets a summary sheet and a data sheet 5 2 01 SUMMARY The summary sheet consists of the following separate blocks a Pavement Inventory This block describes the inventory of the project The survey date should also be included in this block b Pavement Type Pavement types and their limits should be provided in this block for the viewer Comments should be made in this block to let the engineer be aware of any findings that may be useful for rehabilitation design or any issues with the radar data such as presence of noise due to interferences from other sources c Summary Statistics amp Plot Settings This is the only block in the summary sheet that
23. data exported by RADAN software into an ArcGIS format will be developed and documented b Data that is transferred into ArcGIS using the procedure developed in step a will be presented using two different mapping processes The standard process includes written instructions for GPR and GPS data conversion and transfer process a statewide Minnesota mapping process showing the locations of GPR data collection projects and a method of prompting the user for the required information The statewide map layer point layer developed will display the following attributes of the GPR projects GPR project type Mn DOT district Trunk Highway number Project limits The date the data was collected GPR data file name Nu mop ore p The attributes for the projects listed above are searchable and able to be sorted and outputted into a written report format which will include a printed Minnesota ArcGIS project location map A more detailed level of project mapping developed shows the GPR vehicle track as data was collected At each point a GPR GPS data point is recorded the pavement thickness data will be mapped by color coding the GPS locations line layer If there was a core taken at a certain point the coring information of the cores is mapped by color coded GPS locations point layer The mapping system also allows the user to click on individual project points on the map for the detailed information by hotlink to the color coded pavement
24. e 15N Keyhole Markup Language KML is an XML based language for defining the display of three dimensional spatial data KML files have either a kml file extension or a kmz file extension for zipped KML files Support for KML 2 0 is included in the ArcGIS 9 2 release The purpose of adding KML functionality to ArcGIS is to allow interoperability between ArcGIS and the Google Earth system ArcGIS can act as a client for KML data It can also export KML files for sharing with others and serve KML content to the Google Earth browser In ArcGIS KML data is represented using a KML Layer KML layers are supported in ArcGlobe ArcGIS Explorer and the ArcGIS Engine Globe control Like other layers such as feature or raster layers a KML layer is based on a data source appears in the table of contents has a context menu property sheet and associated toolbars and tools The ArcGIS KML layer treats the KML document as read only information It does not support functionality for interactively editing or creating new KML content You cannot use KML elements as input for analysis operations The Data Interoperability Extension allows you to add KML data formats directly to ArcMap and ArcGlobe The steps required for this procedure are the same as adding Geodatabase feature classes or shapefiles as follows 1 Start ArcMap or ArcGlobe Enable the extension if need be 3 Click the Add Data Re button The Add Data dialog opens 4 Click t
25. ed prior to exporting Only depth of steel bars can be exported in this operation KML files can be imported in ArcGIS 9 2 as a line layer The GPR results can also be exported from the ASCII test file with the file extension of lay as a result of picking The test files should be imported into either Excel or Access applications to create coma separated text files that can be imported in ArcGIS 9 2 as a point or line layer 3 4 DEFECT TARGETS A phase inversion occurs at a concrete air interface because of the low dielectric of air A phase inversion is a flip flopping of the normal polarity sequence So instead of a positive negative positive white black white peak the phase inverted sequence is negative positive negative black white black A concrete air reflection starts with a negative black peak followed by a positive white peak 3 4 01 TIME ZERO Time Zero function will shift the vertical scale so time zero is aligned with the surface reflection in each scan After opening the data file that will be processed it is possible to run the process by selecting Process gt Infrastructure then selecting Structure Identification to open the dialog window The processing parameters should be selected as follows a Check Set time Zero b Select the antenna of 5100 1 5 GHz 3 4 02 FIR FILTER RADAN contains Vertical and Horizontal FIR filters FIR filters when encountering a feature in the data are guaranteed to output a fini
26. elect 115200 i Click OK once you are satisfied that you have set up the system to your desired parameters The SIR 20 collects data with a project file system The Project file defines settings for the whole data collection project and then collects a series of data files with some common settings A new collection project is created by going to File New with the following file convention the name should not be more than 8 characters because the name will be cropped after the eighth character First numerical digit Computer Number Second letter Data Collection Direction W West E East N North S South Third and fourth numerical digits Section Number Fifth and sixth numerical digits Pass Number Seventh and eighth numerical digits Processing Sequence Number omeoceme Survey wheel data collection method will be used In this method the system is equipped with a DMI so that the rate of data collection scans per foot can be controlled These devices allow collecting data at a specific even scan spacing so that data is collected with a linear horizontal scale no matter what speed of collecting data at Survey wheel should be calibrated by laying out a 100 foot distance with tape measure and by doing the following steps in SIR 20 a Enter the distance in the Calibration Distance window and inch the vehicle forward so that the front wheel is at that start of the tape b Click Calibrate and drive to the e
27. es found Also the GPR surveys requested by Districts often involve operations in small localized areas off the roadway where highway reference posts are not applicable The antenna mounting system used by Mn DOT previously allowed only one single air coupled antenna to be operated and was of poor design A more robust system for GPR surveying using dual air coupled antennas was identified as a need The simultaneous use of dual GPR antennas provides redundancy in data collection and a comparison tool to improve accuracy and completeness of the survey results The GPS positional data obtained also had be coordinated with the GPR data and made available to the districts in a user friendly exportable format The development of a standard format for GPR data reporting at Mn DOT was indicated as a potential improvement Also the accurate coordinate data acquired with GPS system developed with this project could be used to apply ArcGIS mapping and database capability to the GPR reporting Incorporating GPS into this kind of pavement management survey has been requested by Mn DOT soils engineers and industry partners and is important for effective data sharing Because the addition of GPS equipment data collection and mapping to the GPR system increases the complexity and difficulty of standard survey operations a GPR user manual was requested The user manual would describe GPR vehicle and manual survey operations data collection and analysis map
28. fied and picked from the data The interface can be found in the data as a series of positive or negative peaks Whether the peaks will be positive or negative depends on the dielectric properties of the layers above and below the layer interface Positive peaks appear when the radar wave passes through an interface from a material with lower dielectric permittivity to a material with higher dielectric permittivity and vice versa for the negative peaks The results can be saved in a comma delimited file with an extension lay This output contains the thickness information as well as other useful information such as the propagation velocity reflection amplitude and two way travel time 3 2 04 EXPORT Project information are stored in the header file and exported into tabular data that contains geographic locations in the form of x y coordinates to your map The GPR results can be directly exported to KML files under the conditions that the GPS coordinate systems have be enabled prior to exporting A KML file is a file type used to display geographic data KML files have a tag based structure with names and attributes used for specific display purposes KML files can be imported in ArcGIS 9 2 as a line layer The GPR results can also be exported from the ASCII test file with the file extension of lay as a result of picking The test files should be imported into either Excel or Access applications to create coma separated text files that can be impo
29. he Look in drop down arrow and navigate to the folder or Interoperability Connection that contains the external data source as shown below June 11 2010 GPR OPERATION MANUAL 1 1 Add Data Look ix E MyData cyBuildings kml Add Data Look im ER Interoperability Connections Connection to Iowa counties fdl Connection to Route16 fal Name Show of type nwe ooo Show of ype Datasets and Layers C Cancel 5 Click the data source and click Add 4 2 03 SERVICES You can also use a service as a basemap to go under your local data For example you might use satellite or aerial photographs or administrative boundaries from a service and then overlay your own data such as parcels land uses or demographics A GIS portal provides access to a variety of data and services gathered together in one clearinghouse GIS portals organize content and services such as directories search tools community information support resources data and applications They provide capabilities to query metadata records for relevant data and services and link directly to the online sites that host content services Another place you can find data is in a metadata service provided by an organization or agency These services are online catalogs of metadata that can be searched and browsed over the Internet to find and access data Each metadata service has a Metadata Explorer Web page that allows you to search
30. he settings Display 7 Statistics M Plots Data E Thickness for HMA or 7 PCC E Cross Slope EG Rut Depth Lanes M All or MLIRi ML2R2 9 L3R3 IM L4R4 9S L5R5 M L6R6 Limit J Minimum Maximum Mai Unit Min Uni x 036 1020 10 950 or Initialize y 00 20 20 19 SUMMARY STATISTICS canes L Direction in Figure 2 6 TH 96 Sample Report At the completion of the project certain key information will be captured from the data spreadsheet and stored in a project history database file The database file will contain project name date and GPS positional data that will be periodically exported into an ARCGIS shapefile The shapefile that contains the project info will be shared with MnDOT districts and other interested people Instructions will be provided about how to load the shapefile into the MnDOT Interactive Basemap located on IHUB at http gisservices dot state mn us mndot basemap The TH96 test project info was exported into a shapefile and loaded into the interactive basemap as a test of that process Examples of how this output appears are shown in figures 2 7 and 2 8 11 Figure 2 8 MnDOT Basemap TH 96 Project Detail 12 2 4 DEVELOPMENT OF GPR MANUAL Throughout the term of this project all aspects of the steps needed for GPR field operations data functions were being observed recorded and compiled for development of a GPR user manual A successful GPR manual would
31. ing of the standardized reporting format Coordinate Mn DOT GPR and GPS data collecting and mapping activities with each District Provide GPR and GPS data collecting and mapping products and services as necessary for planning design construction and maintenance of the transportation system June 11 2010 GPR OPERATION MANUAL 1 1 1 2 02 GPR SECTION ACTIVITIES Develop and implement GPR and GPS data collection and mapping procedures and training Test and research new GPS and GPS data collection and mapping methods and equipment for Mn DOT Budget purchase and integrate these new methods and equipment Represent Mn DOT with governmental agencies and professional and private organizations Work with the District Offices to provide training to GPR and GPS data collection and mapping personnel in applications of pavement thickness surveys pavement steel reinforcement and load transfer surveys concrete pavement defect surveys and project mapping Coordinate Mn DOT GPR and GPS data collection and mapping activities with each District Engineer Provide GPR and GPS data collection and mapping products and services as necessary for planning design construction and maintenance of the transportation system 1 2 03 REQUESTS FOR SERVICES FROM THE GPR SECTION In order to avoid duplication of work and effort on a project requests for GPR data collecting and mapping services should be channeled through the appropriate District Office The Di
32. king Criteria Negative Peak Velocity Calc User specified or Core Data a Name Defect b Color Red c Size 5 d Diameter 0 e f The target points can be picked either using single point The pick locations depths and reflection amplitudes are stored in an ASCII file lay when the user selects the Save Changes option An ASCII file can be opened and edited many times 3 4 05 EXPORT Project information are stored in the header file and exported into tabular data that contains geographic locations in the form of x y coordinates to your map The GPR results can be directly exported to KML files under the conditions that the GPS coordinate systems have be enabled prior to exporting Only depth of defects can be exported in this operation KML files can be imported in ArcGIS 9 2 as a line layer The GPR results can also be exported from the ASCII test file with the file extension of lay as a result of picking The test files should be imported into either Excel or Access applications to create coma separated text files that can be imported in ArcGIS 9 2 as a point layer June 11 2010 GPR OPERATION MANUAL 1 1 CHAPTER 4 MAPPING 4 1 INTRODUCTION A standardized mapping process is developed for GPR project information and data specifically designed to report GPR results in an ArcGIS format The developed ArcGIS mapping process will provide the following capability a A standardized process to convert the GPR and GPS
33. l b Handbook for GPR Inspection of Road Structures c RADAN Version 6 6 Manual June 11 2010 GPR OPERATION MANUAL 1 1 2 2 02 GPS The Trimble ProXRT GPS receiver uses H Star technology in real time by connecting to a real time correction source for decimeter 10 cm to subfoot 30 cm positions in the field A wireless link to your local VRS network or local base station can be used for the flexibility The ProXRT GPS receiver is also capable of using the OmniSTAR XP 20 cm accuracy services Installing the GLONASS option on GPS Pathfinder ProXRT receiver increases the number of GNSS satellites that can be observed when working in the field GLONASS improves the ability to maintain lock on enough satellites to keep working when sky visibility becomes limited in tough environments Tracking GLONASS satellites as well as GPS satellites can also improve productivity by reducing the time required to achieve real time decimeter or subfoot accuracy The National Marine Electronics Association NMEA pronounced NEE ma has generated a standard set of messages for communicating GPS information GPR uses the NMEA 0183 version 2 1 protocol that requires the NMEA output from a Pathfinder ProXRT GPS receiver GPS Pathfinder ProXRT Receiver User Manual To configure NMEA output on a GPS Pathfinder ProXRT receiver the NMEA output option must be enabled on the receiver The following settings have been modified from their default values on the
34. l photo to map the test data The process for properly configuring the equipment transferring the GPS GPR data and developing the maps needed was well defined and submitted by AET ArcGIS is versatile mapping software that meets the identified needs of the project and is the preferred supported mapping software for all GIS users at Mn DOT Both the system and project level GPR mapping that will now be normally produced will be readily available to all interested users in ArcGIS format GPR data is attached to each GPS location and can be labeled organized and presented in several desired mapping schemes depending on the project requirements Visual examples of the mapped TH96 test section GPR data are shown in figures 2 4 and 2 5 ETTITTETEZ 13 Ein Edt View Bookmarks nsert Selection Tools Window Help d 0388 Ax 2 1385 7132 GE CE Layers aa E ebtho6 repeojected Ij whih 6 reprojected Corings Ij GPR Propert O Whole TH9 v B sr PA UTM PLNLOGN UL LPO UTM PLN DGN G RI S2LIPC UTM PLN DGN C Jess a eh LE esp Jenja Duero GA SB GR Fo pomo k OA OF A v X a Ani Jh pry Av Qv Jv oe 506240 622 4999216 469 Feet Figure 2 4 Mn Trunk Highway 96 GPS GPR mapping test Th96 test project mxd ArcMap ArcView File Edit Vew Bookmarks Insert Selection Tools Window Help 0508 Bn xx 2 230 1e amp Lovers z GR Projet O whole 196 a B S211PA UTM
35. markers as necessary should be inserted manually to indicate the following a Starting and ending points and or mileposts if present of the section under survey b Any physical objects with known milepost e g bridges intersections railroad crossing and etc c Pavement changes After the data collection is completed the data should be copied and pasted to the GPR data server or hard drive If the coring was conducted these results should also be saved in the same project folder The field notes taken by the operator s should be scanned and saved electronically 2 3 06 VERIFICATION CORES The accuracy of the analyzed GPR data will be determined by correlating the computed layer thickness values to core data which have not been used in the analysis process Where possible the short scans will be selected to cover areas where cores have already been taken Where core data are not available for correlation GPR data will be used to recommend locations for coring June 11 2010 GPR OPERATION MANUAL 1 1 CHAPTER 3 ANALYSIS 3 1 INTRODUCTION The Road Structure Assessment Module RSA in RADAN is a specialized data processing tool used to assess thickness depth and physical characteristics of multiple road layers The RSA module can be used to process data obtained with GSSI SIR Systems using the 1 GHz Model 4108 or 2 GHz Model 4105 horn antennas The collected GPR data should be processed using GSSI s RADAN 6 6 software
36. nd mapping functions in the department This manual contains material that is of both an informational and instructional nature Guidelines and procedures are spelled out in detail in the hope that greater uniformity and quality can be obtained in GPR and GPS data collecting and mapping related activities within Mn DOT The manual clarifies procedures technical and professional GPR data collecting and mapping personnel use in their day to day work Using these procedures should result in uniform GPR and GPS data collecting and mapping practices The manual introduces procedures to work with GPR systems now being used throughout Mn DOT 1 1 02 SCOPE The manual is written for use at the Senior Highway Technician level or above The manual contains definitions of common GPR and GPS data collecting and mapping terms used to communicate with colleagues and clients The manual also references other Mn DOT manuals and other references as necessary for understanding a topic 1 2 GPR SECTION OFFICE OF MATERIALS AND ROAD RESEARCH 1 2 01 GPR SECTION FUNCTIONS Develop and implement GPR and GPS data collecting and mapping procedures and training Test and research new GPR and GPS methods and systems for Mn DOT Budget purchase and integrate these new methods and systems Represent Mn DOT with governmental agencies and professional and private organizations Work with the District Offices to provide training to GPR and GPS data users in understand
37. nd of that distance c Record the number of ticks Collecting synchronized GPS data consists of the following steps a Press the Enable GPS button in the dada collection mode There may be a delay of several seconds before you see the GPS information appear in the window b Make sure you are receiving valid GPS information GPS must be receiving 4 or more satellites in order to provide a good solution c Run the project and start collecting a file You should hear a beep within the first several seconds of collecting a file This beep signifies that GPS information is synchronized with the GPR file d Upon closing the GPR file you will see a window pop up signifying that GPS data is being downloaded from the logger This may take anywhere from several seconds to more than a minute depending on the length of the file June 11 2010 GPR OPERATION MANUAL 1 1 Data Collection Mode A21 xl FREE RUN ENABLE GFS Latitude praza Longuda 22156 SURVEY WHEEL te Time a fa paa Number of Satelites 41 Signa Quafiy HDOP 15 D ta Vaid AUD CALIBRATE SW RosdDoctor CAM Link Output POINT MODE coed oe When the following Configuration window appears the value of 512 should be selected in the Samp Scan drop down box Also the values for Scans ft and ft Mark should be changed to 1 and 528 respectively All GPR surveys for pavement thickness at highway speed should be conduc
38. nna detects the object from far off and is moved over and past it Migration is a technique that collapses hyperbolic diffractions The Kirchhoff method should be selected for migration by adjusting the shape of the Ghost Hyperbola in the following steps a Left click and hold the mouse button when the cursor is over the center of the Ghost Hyperbola to drag the Ghost Hyperbola to center it over a real hyperbola in the data b Use the Shaping Handles to match the shape of the Ghost Hyperbola to a real one by covering up the entire real hyperbola using to tails of the real hyperbola to help shaping c Adjust the Width by left clicking and holding on the Slider Bar Handle at the top or the bottom of the profile window to make the slider bars to be wide enough to encompass the real hyperbola but not so wide as to include adjacent hyperbolas d Click on Run 2 D Constant Velocity Migration 3 3 03 INTERACTIVE TARGET TRACKING Interactive Interpretation allows the user to semi automatically locate and analyze features in radar data by placing picks on the data A pick is a peak of amplitude identified in a scan that can correspond to a point target The hyperbola becomes a point after migration that can be picked If this is the first time on a GPR image file after it was processed in Time Zero and Migration there is no result ASCID file associated with it It is possible to run the process by selecting View gt Interactive to open
39. ontracted in 2009 AET was tasked with creating a standardized ARCGIS mapping and reporting format for the collected GPR GPS data A test section for the new GPR GPS system was identified on TH96 between TH61 and TH95 This section was already scheduled to be GPR surveyed in 2010 as part of the regular GPR production work The TH96 test data was useful for this purpose as it represented a real life GPR project and had the type of road conditions expected to be regularly encountered The field data collection took place in March of 2010 and GPR GPS system performed as expected The data along with Mn DOT cad mapping was collected and transferred to AET for reporting and mapping development Two different types of GPR mapping were identified as needs First project level mapping which shows the actual route the GPR vehicle or hand cart travels This is needed because of the extreme variability of the subsurface materials often encountered precise positioning and mapping is needed to properly correlate the GPR readings to points the data is taken The second level of mapping needed is system level to show where in the state or district GPR projects have been completed This is useful for project tracking and provides information to Mn DOT soils and materials engineers The process for mapping GPS GPR data using ARCGIS was completed by in June 2010 Microstation mapping was acquired from Metro Design and was used along with an aeria
40. ositional data obtained will be precisely coordinated with the GPR data and both the layer analysis and project locations will be made available to the districts in an easy to use viewable and or exportable format Because the addition of GPS equipment data collection and mapping to the GPR system will increase the complexity and difficulty of standard survey operations a GPR user manual was developed as part of this project The user manual describes GPR vehicle and manual survey operations data collection and analysis mapping using ArcGIS and describes a method to standardize the GPR data reporting The manual was written in the proper format for potential inclusion in the Mn DOT standard manual series The tasks accomplished with this project will improve the efficiency and effectiveness of the ground penetrating radar GPR program at Mn DOT 13 APPENDIX A TEST PROJECT FOR VEHICLE FRONT MOUNT TH 1 2009 Red River Flooding GPR Study Survey for voids and deterioration caused by floodwater overtopping by Red River of the North Approximate Location TH 1 From Milepost 0 86 to Milepost 3 56 Eastbound and Westbound traveling lanes both wheel paths In Oslo MN Mn DOT District 2 May 2009 Background The project location is along MN THI east of the town of Oslo in Mn DOT district 2 The project area is between Milepost 0 86 and 3 56 TH1 in this area is a 2 lane rural highway with minimal shoulders The pavement is Bituminous o
41. pair Most voids located during the GPR survey were associated with pavement cracks that had been widened or washed out by the flooding Most of the voids and damage was visible on the surface However some subsurface voids appeared at crack locations where the pavement surface looked fairly sound The moist materials caused degradation of the radar signal below approximately 3 feet but voids above that depth in the wheel paths were observed with a high degree of confidence A utility crossing visible in the radar data during testing verified that the GPR equipment was functioning and was able to view anomalies at depths of at least 36 inches with expected resolution Voids visible in the radar data after post processing in the office are summarized in the spreadsheet shown in the following pages Note that the radar data measures conditions directly under the path of the antenna in an approximately 1 foot wide scan path Voids outside the survey path will not be visible nor will any anomalies be visible deeper than approximately 48 inches the maximum depth range Cracks that had been totally washed out and temporarily repaired at the time of GPR surveying may not appear in the following spreadsheet No extremely large un collapsed voids appeared in the GPR survey of the traveling lanes The spreadsheet summarizes the crack void locations at distances in feet going eastbound starting from the overhead power line crossing at MP 0 86 16 P
42. ping using ArcGIS and a standardized data reporting format Therefore it was determined that an additional GPR project would be beneficial in order to accomplish the necessary tasks and to incorporate global positioning system GPS data collection and mapping capability into Ground Penetrating Radar GPR operations for pavement evaluations 1 2 OBJECTIVE The overall objective of this project is to incorporate GPS and mapping capability into Ground Penetrating Radar GPR operations for pavement thickness evaluations At the conclusion of this project enhanced GPR data collection and reporting methods will be available to all Mn DOT users The addition of GPS capability will allow detailed mapping of GPR survey projects and improve the positional accuracy of subsurface locates Defining and clarifying GPR operations with the development of standardized reports and a user manual will benefit current and future employees involved with the system at all levels The analyses described herein presents the compilation of the projects tasks as a final report Task 6 1 3 SCOPE The GPS for GPR implementation study included the following activities a b c d a e Upgrading the data collection vehicle to allow dual antenna GPR data collection by installing and testing a compatible antenna mounting device on the Mn DOT GPR vehicle Incorporating GPS capability in to the GPR system by identifying and obtaining suita
43. rences from the power lines and telecommunication can be reduced significantly However spurious radar echoes known as clutter can also be expected in many test areas because of buried debris such as old rails wire scraps boulders and small metal objects Usually a trained operator can interpret the desired radar signatures in the midst of a moderate amount of such clutter Performance is also limited by signal scattering in heterogeneous conditions e g rocky soils Interpretation of GPR records is an art as well as a science even with the best available state of the art radars Interpretation of radar grams is generally non intuitive to the novice Considerable expertise is necessary to effectively design conduct and interpret GPR surveys June 11 2010 GPR OPERATION MANUAL 1 1 CHAPTER 2 SURVEY 2 1 INTRODUCTION Road Structures are defined here as the layered asphalt or concrete paving and any geo textiles base and sub base materials While it is sometimes possible to detect buried utility lines that particular application is not a focus of the RoadScan technique The RoadScan technique described here involves the use of a GSSI SIR 20 control unit Model 4105 4105NR 4108 or 4108 F Horn antennas and some type of distance measure instrument DMI The unit is mounted on a vehicle for high speed data acquisition Data processing is done with GSSI s RADAN processing software with Road Structure Assessment module The RoadScan
44. rted in ArcGIS 9 2 as a point or line layer The output from RADAN can be imported into MS Access for further summarizing the layer thickness at 100 ft interval and the reported thicknesses are the averages of those from one or both wheel paths 3 3 STEEL TARGETS When the antenna crosses a target tie bar rebar at a right angle the resulting image looks like a hyperbola In all GSSI antennas steel target reflection is a copy of the transmit pulse that has a certain polarity positive peak first then a negative peak possibly followed by a second positive In a grayscale line scan this looks like a white band followed by a black band then possibly another white June 11 2010 GPR OPERATION MANUAL 1 1 3 3 01 TIME ZERO Time Zero function will shift the vertical scale so time zero is aligned with the surface reflection in each scan After opening the data file that will be processed it is possible to run the process by selecting Process gt Infrastructure then selecting Structure Identification to open the dialog window The processing parameters should be selected as follows a Check Set time Zero b Select the antenna of 5100 1 5 GHz c Check Background Removal 3 3 02 MIGRATION The radar antenna radiates energy with a wide bandwidth pattern such that objects several feet away may be detected As a consequence of this objects of finite dimensions may appear as hyperbolic reflectors on the radar record as the ante
45. s and underdeveloped project mapping and reporting process The objectives of this project were first to develop a more robust system for GPR surveying using dual air coupled antennas to provide redundancy in data collection and to improve accuracy and completeness of the survey results Secondly the addition of Global Positioning System GPS location data acquired in coordination with the GPR data for improved project location and ArcGIS mapping capability Thirdly the development of a standard format for GPR data reporting in a more user friendly exportable format After completing the other objectives a GPR Manual was developed describing GPR vehicle and survey operations GPS with GPR data collection mapping using ArcGIS and the new standardized reporting format The result was an improved and better documented subsurface data collection and reporting process that incorporates GPS and improves the effectiveness of Mn DOT s GPR program 17 Document Analysis Descriptors 18 Availability Statement Ground Penetrating Radar GPR GPS for GPR dual air No restrictions Document available from coupled antennas Global Positioning System GPS ArcGIS National Technical Information Services mapping GPR data reporting GPR Manual Alexandria Virginia 22312 19 Security Class this report 20 Security Class this page 21 No of Pages 22 Price Unclassified Unclassified 49 Incorporating GPS and mapping capability into Ground Penetr
46. s radar system Geophysical Survey Systems Inc GSSI of Salem NH USA Because the system was designed to mount the GPR antennas that MnDOT already had and was fully compatible with the system it was determined to be the best option for upgrading the GPR survey vehicle mount The system was purchased from GSSI and installed by Mn DOT Central Shops in April of 2009 The vehicle was configured and proper operation of the vehicle mount took place at the Maplewood Research Lab in May 2009 The first field trial of the rig was done in Mn DOT District 2 near the town of Oslo Mn The work required testing of MN TH1 in an area that had recently experienced flooding The new vehicle front mount performed well and no problems were experienced See the GPR survey report of TH1 testing in Appendix A The new vehicle front antenna mount system also allows simultaneous dual channel data collection which gives additional information and flexibility It also provides faster safer and more stable vehicle survey operations especially at highway speeds Figure 2 1 Previous GPR vehicle antenna mount Polk Norman BP Becker j Perinington Red take ne ut J a orwolor E Hubbard PET PEE I Otter jal edeni w Figure 2 3 Mn Trunk Highway 1 Test Site Location 2 2 INCORPORATING GPS CAPABILITY IN TO THE GPR SYSTEM In January of 2009 a separate literature and internet search was performed
47. strict Pavement Engineer is responsible for their GPR and GPS records and should be knowledgeable about past and present respective district data collecting and mapping activities Each District submits the GPR requests along with Falling Weight Deflectometer FWD requests or submits GPR requests for individual projects separately These requests should be sent to the GPR Section as soon as possible in order to efficiently schedule projects A minimum of one month s notice is usually requested for GPR surveys Requests for GPR survey should include the following information Roadway ID e g US 10 TH 52 County Name e g Ramsey Project Limits e g MP 171 700 to MP 188 900 Exceptional Needs e g Test on shoulder Call for distress and roughness surveys Recommended Due Date cao fp After a request has been received the GPR Request Tracker an EXCEL spreadsheet should be updated and field work should be scheduled accordingly June 11 2010 GPR OPERATION MANUAL 1 1 1 3 LIMITATIONS The most significant performance limitation of GPR is in high conductivity materials such as clay soils and soils that are salt contaminated or water saturated GPR surveys should be performed in the dry season if at all possible especially when base and subbase layers are of interest Soil moisture especially in high clay soils only increases the radar attenuation rates further limiting the radar performance With the noise reduction the interfe
48. te filtered version of that feature The Triangular FIR filter should be used for filtering defect features in concrete pavement The Triangular filter emphasizes the center of the filter more heavily than the ends of the filter This type of filter is a weighted moving average with the weighting function shaped like a triangle A portion of the June 11 2010 GPR OPERATION MANUAL 1 1 data determined by the filter length is multiplied and summed by this function The result is output at the center of the triangle FIR filter settings should be the followings a Background Removal scans 349 b Low Pass MHz 500 c Filter Type Triangle 3 4 03 RESTORE GAIN The Restore Gain function removes the gain applied to the data during acquisition Restoring gain is an important option should you wish to export your data to a forward modeling program or determine the dielectric permittivity conductivity and dispersion approximate attenuation of layers The Restore Gain function uses gain information found in the file header to remove the gain function and normalize the gains 3 4 04 INTERACTIVE TARGET TRACKING Clicking on the Target Options menu item from the Main Menu opens up a list box containing the names and properties of all of the targets Targets are added by clicking M Target The new target properties are edited by placing the mouse cursor over the target name and double clicking The following properties should be used Pic
49. technique used for PCC pavements involves the use of a GSSI SIR 20 control unit Model 5100 1 5 GHz or Model 5100B 1 6 GHz antenna and some type of distance measure instrument DMI The RoadScan technique used for Utility involves the use of a GSSI SIR 20 control unit Model 5103A 400 MHz and Model 3207 100 MHz antenna and some type of distance measure instrument DMI The current state of the art has competent practitioners review each project site for adequate pavement and soil conditions and employ GPR when it is suitable They use multiple frequencies and use GPR in conjunction with other techniques A site appropriate survey and data referencing methods are selected Data can be collected in closely spaced parallel profiles and combined in a 3 D volume of data for post processing and time or depth slice interpretation While GPR is still rarely used for conventional locating it is becoming more common as equipment costs drop and ease of use improves June 11 2010 GPR OPERATION MANUAL 1 1 2 2 EQUIPMENT 2 2 01 GPR The GPR equipment currently used by Mn DOT is summarized in Table 2 2 All of this equipment has been purchased from Geophysical Survey Systems Inc in North Salem NH This equipment consists of two data collection systems SIR 020 and SIR 2000 two data collection and analysis software packages RADAN and ROADDOCTOR 3 ground coupled GC antennas 100 MHz 400MHz and 1 5 GHz and 2 air coupled AC antennas 1
50. ted in this setting unless the survey is for a special research need The detailed settings under different conditions are shown in Table 2 3 Configuration Config Type Config Name HIGHWAY v 2 2GHz SIRveyor Number of channels Chan 1 Chan 2 e e amp Samp Scan Transmit Rate ass il DC TiRi1 T2jR2 Scans Sec DielConstant Transmitter z Chani T1 Ri Chan2 T2 R2 Scans ft Receiver ft Mark Auto Gain Level lt Back Cancel Help June 11 2010 GPR OPERATION MANUAL 1 1 Table 2 3 Parameter Settings Application Asphalt Concrete Pavement Thickness Configuration Type Highway Channels 2 Configuration Name H2GHz_400MHz Speed miles hour 60 30 30 Scans per second 200 Dielectric Constant 6 25 Scans per foot 1 2 1 Foot per mark 100 0 5 Auto Gain Level 0 5 0 5 0 5 Next step is to open the Macro window This window will allow for either creating a new macro or attaching an existing macro If there are no pre saved macros on the system the new macro should be created Upon clicking the button for Create New Macro and clicking Finish the antenna will initialize clock will count a few seconds and then data will scroll across the screen You will need to make a few adjustments before beginning collection The steps below should be followed a Configure Position Check Gain c Check Filter The correct filter settings of different antennas are listed in Table 2 2
51. ts the mouse pointer turns into a pointing hand and you see a pop up tip with the name of the target c Click the feature A hyperlink is invoked If more than one hyperlink has been defined for the feature you clicked a dialog box will appear from which you can select the hyperlink you want to launch 4 3 04 INTEGRATION The integration of all project related files consists of two major stages initial and expanding The initial stage is focused on setting up a statewide Minnesota mapping process showing the locations of GPR data collection projects The expanding stage is involved in adding the new GPR projects to the existing map with elapsing of time 4 4 WEB APPLICATION 4 4 01 GPR PROJECTS The GPR projects shape files should be imported into the Mn DOT web based interactive basemap that can be accessed via http gisservices dot state mn us mndot basemap June 11 2010 GPR OPERATION MANUAL 1 1 Mndot Basemap Windows Internet Explorer GO v amp http fgisservices dot state mn us mndot basemap File Edit View Favorites Tools Help Xo gg HUB Home mindot Basemap x p Minnesota Department of Transportation ee LEER Click here to select a toolbar TTSISIS BIE javascript Geocortex_Essentials_Web_UI_WebControls_Toolset_MenuOnClick a In the web based GIS map as shown above there is a pulldown menu in the toolbox at the upper left The down arrow should be clicke
52. unt of research required will depend on the needs of the project The following documents may contain useful project information a Construction Plans Both State and County plans will furnish construction centerline alignment and reference termini of the constructed highways The plans will also furnish pavement design that includes materials types and design thickness of pavement layers and reinforcement and load transfer design for PCC pavements b Geotechnical Reports Geotechnical reports will furnish subgrade soils types and moisture conditions of the constructed highways 2 3 02 WORK PLAN The GPR data collection is planned after the project information has been completed The project starting and ending locations are identified for route planning The work plan should include the following major components a Safety b Quality 2 3 03 SYSTEM PARAMETER SETUP The project number will be used to create the project folder to keep this data organized prior to staring data collection program If the project number is not available the roadway ID and staring milepost will be used to create the project folder A new project should be created under that folder with a unique name The followings are steps to define the folders previously created and set some other parameters a Start from the initial RADAN SIR 20 screen b Find the View pull down menu at the top of the screen and click on it Look for the Customize options c Click
53. ver granular base In spring of 2009 the Red River of the North experienced severe flooding and overtopped TH1 to a depth of more than 1ft in this area causing deterioration of the shoulders and some of the pavement cracks Temporary repairs were made when the flooding subsided to allow vehicle traffic but the roadway was restricted to 7TON loads at the time of the survey The goal of the Ground Penetrating Radar GPR survey was to examine the area of the floodwater overtopping for structural soundness and to attempt to detect unknown voids beneath the pavement TH1 Spring Flooding 2009 Surveys The GPR survey was performed on May 5th 2009 Ambient conditions were cloudy and dry however water from flooding was still standing in ditches and subsurface soils were very moist The GPR system used was the SIR 20 manufactured by GSSI The antenna used was the 1 GigHz air coupled attached by a GSSI front vehicle mount system Both Eastbound and both Westbound traveling lanes all four wheel paths were surveyed between Reference posts 0 86 and 3 56 The instrument was attached to the front vehicle mount and driven at approximately 10 MPH Traffic control in the form of GPR vehicle protection was provided by District 2 Maintenance forces Mn DOT GPR Survey Vehicle with vehicle antenna mount 15 Results Subsurface void locations that were visible in the data at the time of surveying were immediately marked in the field for evaluation and re
54. vigation and then just to the right are in out and pan At the left there is layer list The map layer created in the previous chapter should be checked When the map is ready to print the down arrow should be clicked to select print and then just to the right is print The project details map is printed using the following steps Select a page size Select an output format Select Show All Layers Type the project title Enter the map description Press View Press Download e meno gsp
55. will prompt you to save the new processed file Give the file a unique name and click Save Remember to add display gain Note that in the processed data file the pavement surface is now flat and Time Zero is now at the pavement surface 3 2 03 INTERACTIVE LAYER TRACKING The processed antenna calibration file is used to process the raw data files in the process called the horn reflection picking which eliminates the effect of bouncing of the van during data collection In addition the vertical time scale is automatically adjusted such that the zero time corresponds to the point of time the radar wave reaches the pavement surface instead of the time the radar wave leaves the antenna There should be at least two markers indicating the beginning and ending locations of the section After the beginning and ending locations are identified in the data the horizontal scale should be June 11 2010 GPR OPERATION MANUAL 1 1 corrected such that those locations match the mileposts of project termini For increasing direction horizontal offset can calculated as X offset 5 X actual X RADAN For decreasing direction horizontal offset can calculated as X offset X actual X RADAN When this offset value is inputted into RADAN by selecting edit gt edit database gt regions position the horizontal scale will be updated To obtain the depth to a layer interface using RADAN the interface under consideration should be identi

Final Report - Minnesota Local Road Research Board

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