COLLEGE COLLEGE OF ENGINEERING & COMPUTER SCIENCE ASSOCIATE DEAN: DR. MOHAMMAD ILYAS GEOMATIC ENGINEERING PROGRAM

Transcription

1 COLLEGE COLLEGE OF ENGINEERING & COMPUTER SCIENCE DEAN: DR. KARL STEVENS ASSOCIATE DEAN: DR. MOHAMMAD ILYAS GEOMATIC ENGINEERING PROGRAM INTERIM PROGRAM DIRECTOR: DR. DON LEONE P.E. STAFF & FUTURE ENGINEERS, SURVEYORS, ARCHITECTS & SCIENTISTS Nov. 13 th,

2 SUE, RT and Geomatics How do Subsurface Utility Engineering (SUE) and modern geophysical imaging techniques es such as Radar Tomography (RT) relate to Geomatics? Ralf Birken, Ph.D. Chief Scientist Nov. 13 th,

3 O U T L I N E Introduction Subsurface Utility Engineering i (SUE) and established Geophysics Modern Array-based Land-based Geophysical Methods Radar Tomography Concepts, Systems and Methodology, and Case Histories Electromagnetic Induction Arrays Concepts, Systems and Methodology, and Case Histories SUE and the Impact of Geophysical Arrays Legislation and Certification Summary Nov. 13 th,

4 Introduction Geomatics Engineering is a modern discipline, i which h integrates t acquisition, iti modeling, analysis, and management of spatially referenced data, i.e. data identified according to their locations. Based on the scientific framework of geodesy, it uses terrestrial, t marine, airborne, and satellite-based sensors to acquire spatial and other data. It includes the process of transforming spatially referenced data from different sources it into common information if systems with well-defined accuracy characteristics." Subsurface Geomatics? How do you acquire accurate surveying data of subsurface features? What accuracies can you expect? ww.geomatics.ucalg gary.ca/about/wha tis Nov. 13 th,

5 Subsurface Utility Engineering (SUE) and established Geophysics Greg Jeffries Vice President Nov. 13 th,

6 SUE and established Geophysics Quality Level D (QL D): If Information derived d from existing iti records or oral recollections. Quality Level C (QL C): Information obtained by surveying and plotting visible above-ground utility features and by using professional judgment in correlating this information to QL D information. Based on CI/ASCE standards d and summary by Anspach Nov. 13 th,

7 SUE and established Geophysics Quality Level B (QL B): Information obtained through h the application of appropriate surface geophysical methods to determine the existence and approximate horizontal position of subsurface utilities. QL B data should be reproducible by surface geophysics at any point of their depiction. This information is surveyed to applicable tolerances defined by the project and reduced onto plan documents. Based on CI/ASCE standards d and summary by Anspach Nov. 13 th,

8 SUE and established Geophysics Quality Level A (QL A): Precise horizontal and vertical location of utilities obtained by the actual exposure (or verification of previously exposed and surveyed utilities) and subsequent measurement of subsurface utilities, usually at a specific point. Minimally intrusive excavation equipment is typically used to minimize the potential for utility damage. A precise horizontal and vertical location as well as other utility attributes is shown on plan documents. Accuracy is typically set at 15mm vertical, and to applicable horizontal survey and mapping. Based on CI/ASCE standards and summary by Anspach Nov. 13 th,

9 SUE and established Geophysics Commonly used geophysical methods: Pipe and cable locators Terrain conductivity meters Metal detectors Ground Penetrating Radar (GPR) Magnetic methods Acoustic Methods Optical systems Nov. 13 th,

10 SUE and established Geophysics Common features: Typically handheld or pushcart-based single channel systems Typically no geo-referenced data recording Sparse non-continuous coverage Big gap between QL B and QL A as far as: Cost Accuracy (Horizontal and Vertical) Both lack continuous Coverage Nov. 13 th,

11 SUE and established Geophysics Suggestion to narrow gap between QL B and QL A using: Array-based Surface Geophysical Methods As far as: Continuous Coverage Horizontal and Vertical Position Cost versus Risk Reusable georeferenced digital data Higher COST Lower QL A SUE Quality Levels QL B QL C QL D RISK Higher ih Nov. 13 th,

12 References American Society of Civil Engineers (2002). C/I ASCE 38-02, Standard d Guideline for the Collection and Depiction of Existing Subsurface Utility Data. Reston, VA. Anspach, J.H., 2002 (?), Underground d utility security issues at critical facilities:?, 5 pages. Nov. 13 th,

13 Modern Array-based Land-based Geophysical Methods Multi-channel geophysical systems Deployed through vehicle (some even within traffic flow) Movement tracked through survey-grade positioning system Create accurate geo-referenced digital data sets Able to cover large areas efficiently with dense continuous data coverage Allow more advanced methods of data interpretation Option to combine multiple arrays in single data collection effort Surveyor certified accuracy and final maps Nov. 13 th,

14 Radar Tomography y( (RT) Concept Nov. 13 th,

15 Common 2D GPR Survey Grids 2 feet or more between profiles 4 inches or more between ti triggers (stations) ti Rarely uses accurate geometry control, regarding line spacing and direction Nov. 13 th,

16 GPR Section with Point Reflectors GPR is also looking to the side T R T R T R T R T R T R T R T R T Note: Point reflectors and pipes perpendicular to the profile appear the same in 2D GPR section Nov. 13 th,

17 Array GPR Advantages - I Efficiency in data collection, especially when survey area large (>40, sqft) and target small requiring small profile spacing Standard GPR System 1 Tx Rx channel Array GPR System 16 Tx Rx channels 12.5 cm swath of coverage in one profile Transmitting antenna (Tx) 2.0 m swath of coverage in one profile Receiving antenna (Rx) Nov. 13 th,

18 Array GPR Advantages - II A dense grid of multiple 2D GPR profiles allows synthetic aperture focusing to create a stack of image slices at different depths to create a 3D image below ground. Dense 2D grid becomes 3D GPR grid when profile spacing close to station spacing Depth Goal: One GPR trace every 5 inches or less in in-line and cross-profile direction Nov. 13 th,

19 Radar Tomography y( (RT) Systems and Methodology Nov. 13 th,

20 Radar Tomography (Ground-Penetrating Imaging Radar) Joint development of Witten Technologies Inc., Malå Geoscience, ConEdison Schlumberger, EPRI, GTI (formerly GRI) Nov. 13 th,

21 Radar Tomography (RT) RT: A GPR survey or system that combines efficient radar surveying with precise positioning control and advanced signal processing allowing the creation of high-resolution 3D radar images of the subsurface on a large-scale. Meaning: precise positioning = centimeters large-scale scale = surveys covering thousands of square meters high-resolution = resolution of centimeters Nov. 13 th,

22 Radar Tomography (RT) Methodology Rd Radar Arrays Survey-grade Positioning prism Continues 3D Radar Images Accurate Certified Utility Maps laser theodolite Nov. 13 th,

23 Please wait for movie to start Jax_Region_09_with_pictometry_tweak-2.mov ith i t t t Nov. 13 th,

24 CART Imaging gsystem Computer Assisted Radar Tomography Total daily coverage: 40,000 80,000 sqft Spatial resolution (16 channel mode): ~ 5 channel or cross-line spacing ~ 4 trace or in-line spacing Maximum Driving i Speed: 5 mi/hr Radar component of CART Imaging System is manufactured by Malå Geoscience Nov. 13 th,

25 CART Schematic 400 and 200 MHz antennas Nov. 13 th,

26 Operational Specifications in Words Depth of penetration is 4 to 6 ft in most sandy-clay soils (8 to 12 ft in sandy soils), very site specific, conservative Depth accuracy is about 5% (i.e., ± 3 in. over 5 ft) Horizontal accuracy is about 1% from mapped surface features such as manhole covers or curb lines Resolution of subsurface objects is about 3 to 4 in. Objects as small as 1-in. can be seen at shallow depths Resolution degrades with depth at rate of about 1 in/ft Typically certified to ± 6 in. in all 3 coordinates Nov. 13 th,

27 Positioning System I Robotic Laser Precise geometry control provided by a self-tracking laser theodolite (robotic total station) locking on to a 360 degree prism 3D accuracy of ±[1 ppm + 1 mm]; for example, ±2 mm in 1 km Range of 2 km Self-tracking, accurate reading every 6 s (faster ones available) Standard technology for construction surveying Survey-grade, can be certified by professional surveyor prism laser theodolite Manufactured by Geodimeter (now Trimble) Nov. 13 th,

28 Positioning System II - GPS Precise geometry control provided by RTK GPS system consisting of base station and rover Accurate reading every second 7.2 km/h (2 m/s) recommended speed (one data point every 2 m) Specified Accuracy with sufficient i Satellite coverage: Horizontal: 10 mm + 1 ppm Vertical: 15 mm + 1 ppm Survey-grade, can be certified by professional surveyor Manufactured by TOPCON (Hiper+ gr-2100) Nov. 13 th,

29 Processing, Integration, Visualization The radar data are processed into geo-referenced seamless 3D radar images Those are interpreted for pipes With the help of complementary information gathered with traditional SUE methods the utility types were identified The clients receive certified CAD maps in plan and profile showing the 3D location of each pipe colored coded by utility Autodesk, Microstation or ArcGIS Nov. 13 th,

30 Please wait for example maps 03_2006_Laura_St_Jak_JEA_Phz1.pdf Nov. 13 th,

31 Corrected CAD Maps lines not present on original map telephone duct banks off by ten feet of more W 10 ft water line off by several feet Colored lines show utility locations according to available maps. Black lines show actual locations (of selected utilities) determined by radar tomography. Church St Nov. 13 th,

32 Radar Tomography y( (RT) Case Histories Nov. 13 th,

33 Radar Tomography (RT) Example from the Lower Manhattan Radar Project Nov. 13 th,

34 CART Surveys Near WTC West St. Survey Area Areas surveyed in August 2001 Areas surveyed from December 2001 February 8th 2002 Nov. 13 th,

35 Lower Manhattan Radar Project Help in planning reconstruction of the utility network of Lower Manhattan view north along West St view northeast corner of West and Liberty Nov. 13 th,

36 roadbed joints 20 ft damaged zone wash outs? surface features manhole and valve covers RADAR IMAGE 2 inches below street level Nov. 13 th,

37 radar shadow of roadbed d joints 20 ft A tops of service boxes RADAR IMAGE 12 inches below street level A Nov. 13 th,

38 radar shadow of roadbed joints 20 ft gas electric RADAR IMAGE 24 inches below street level Nov. 13 th,

39 20 ft water RADAR IMAGE 42 inches below street level Nov. 13 th,

40 Please wait for movie to start Nov. 13 th,

41 RT GIS Overview West Street New York City Orthophoto basemap - State Plane (NAD 83) feet Nov. 13 th,

42 Nov. 13 th,

43 Radar Tomography (RT) Case History NYC, Cathedral Parkway Project Nov. 13 th,

44 Cathedral Parkway Project Construction ti Interference Determine if installation of footings for a new walkway along Central Park would require relocation of a high power feeder line Nov. 13 th,

45 Nov. 13 th,

46 view #1 east along walkway Continuouso coverage (mapping) is important t in projects that involve long section of utility lines view #2 northeast #1 DOUGLAS CIRCLE #2 Views of oil-o-static (138kV) lines under Cathedral Parkway near Douglas Circle FRAWLEY CIRCLE Nov. 13 th,

47 Line pair is normally at 36 inches depth except for a short section where it rises to 24 inches (below grade) Map view of lines color indicates depth Nov. 13 th,

48 Cathedral Parkway Mapped ~2000 ft of high-voltage electrical feeder lines over entire length of planned construction ti Cost of $15k ( sq ft at $0.50/sq ft) recovered in fewer test pits needed to verify that construction plan would not affect the lines Number of test pits reduced from 20 (or more) to 5 Cost of a test pit in NYC is about $800 to $3000 Cost Leverage : Reduced risk of having to relocate the lines (a cost of $1 to $3 million) if original maps were inaccurate Nov. 13 th,

49 Electromagnetic Induction Array Concepts Nov. 13 th,

50 Other Transaction Agreement #DTRS56-02-T-0005 Digital Mapping of Buried Pipelines with a Dual-Array System R&D Project funded by Witten Technologies Consolidated d Edison Company of New York U.S. Department of Transportation Research and Special Projects Administration With technical contributions from EMI (a division of Schlumberger) Regional Water Authority of South Central Connecticut Seknion October 2002 December 2004 Nov. 13 th,

51 Mobile platform for urban mapping Nov. 13 th,

52 Arrayed Induction Receivers (AIR) System Methodology Electromagnetic Induction Array Accurate Utility Maps Electromagnetic Field Map Nov. 13 th,

53 Electromagnetic Induction Array Systems and Methodology Nov. 13 th,

54 Arrayed Induction Receiver (AIR) System Array of 16 broadband vector magnetic field sensors (induction coils) Broadband frequency response Flat from 1 to 80 khz Low noise level khz khz Small package 15 cm 3, about 3 kg Built by EMI (Schlumberger) Simultaneous data acquisition of all 48 channels Nov. 13 th,

55 Survey-grade Positioning System BASE STATION PRISM System uses laser theodolite (robotic total station) for survey-grade positioning 3D accuracy of ±[1 ppm + 1 mm]; for example, ±2 mm in 1 km Range of 2 km Self-tracking of 360 deg. prism, accurate reading every 6 s Standard technology for construction surveying Map surface features for local reference map Alternatively use survey-grade GPS Nov. 13 th,

56 EM Source Options Current injection ( clamp-on ) Current injected directly onto pipe by galvanic leads or toroidal clamp Frequencies from 500 Hz to 85 khz Remote induction ( on-board ) Three orthogonal coils of 0.7 m dia. Moment of 5 at 1 khz Frequencies from 500 Hz to 50 khz Reference signal for phase detection Existing signals 60 Hz signals on power lines Nov. 13 th,

57 Electromagnetic Induction Array Case Histories Nov. 13 th,

58 83 khz Lower Hx EM Field Data 0.66m Nov. 13 th,

59 39 khz Total Horizontal EM Field 3.6m 3.3m Nov. 13 th,

60 8.9 khz Total Horizontal EM Field 3.3m 49m 4.9m Nov. 13 th,

61 Dipping Power Line Nov. 13 th,

62 Dipping Power Line Nov. 13 th,

63 EM Complementing Radar Nov. 13 th,

64 Maps and Located Pipes in GIS EM Pipe Picks (gray lines), Radar Pipe Picks (color-coded by depth are superimposed on 65 khz horizontal magnetic field map and 200 MHz Depth Slice at 30 Surface features (symbols) and the curbs in light gray Map was composed in ARCGIS Nov. 13 th,

65 Qualitative Pipe Picks Visualized in GIS Pipe Picks (gray lines) are superimposed on 32 khz horizontal magnetic field data map and high- resolution aerial photo (courtesy of RWA) Map was composed in ARCGIS Nov. 13 th,

66 Another GIS Example Nov. 13 th,

67 Subsurface Utility Engineering (SUE) and the Impact of Geophysical Arrays Nov. 13 th,

68 SUE and the Impact of Geophysical Arrays Suggestion to narrow gap between QL B and QL A using: Array-based Surface Geophysical Methods As far as: Continuous Coverage Horizontal and Vertical Position Cost versus Risk Reusable georeferenced digital data Higher COST Lower QL A SUE Quality Levels QL B QL C QL D RISK Higher ih Nov. 13 th,

69 SUE and the Impact of Geophysical Arrays SUE (QL D, QL C, and QL B) combined with geophysical array technologies (especially RT) have the following advantages: Horizontal and Vertical Position of Utilities typically certified to within 6 inches by WTI professional land surveyor Provide continuous coverage throughout area of interest Cost less than exposure (QL A), more than QL B Risk lower than QL B, almost QL A Reusable geo-referenced digital data improving project design Better-informed more efficient Design Reduces number of exposures (e.g. can guide vacuum excavation) Construction 14% cost reduction, $4.62/$1 ROI* Reduced conflict = fewer change orders Reduced damage = increased safety Faster completion = reduced public nuisance Reduced risk = lower bids Nov. 13 th,

70 Taking advantage of these new technologies' Professional Surveyors certifying results Stronger SUE/ Best Practice mandates (i.e. condition of permit) ROW owners make Project Owners bear the cost of ROW entry Accurate Information AT THE BID: squeeze the risk FDOT: Nov. 13 th,

71 S U M M A R Y 1 Array-based geophysical systems are changing SUE ASCE committee looking into revising i current guidelines FDOT in final step of adopting RT as one of the best practices to be used for certain larger projects Combination of SUE, RT, QL D, QL C, QL B and reduced use of exposures (limited QL A) may proof to be best way to negotiate cost and risk Recommend to: learn and teach about these emerging technologies test and use them in projects for value and cost savings throughout overall project Nov. 13 th,

72 S U M M A R Y 2 Commercial Radar Tomography (RT) Services using the CART Imaging System are offered since early 2001 Deliverables include CAD, Microstation, or GIS subsurface utility maps in 3D located with RT Surveyed several Million of squarefeet over the past 7 years Electromagnetic Induction Array Prototype available for special project to locate deeper conductive utilities Nov. 13 th,

73 WITTEN TECHNOLOGIES, INC. Research & Development 35 Medford d Street, t Suite 306 Somerville, MA r.birken@wittentech.com WITTEN TECHNOLOGIES, INC All rights reserved. Nov. 13 th,