SUBSURFACE UTILITY ENGINEERING: Designation/Location Techniques Used in Utility Conflict Management

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1 SUBSURFACE UTILITY ENGINEERING: Designation/Location Techniques Used in Utility Conflict Management Presented to: 2018 LADOTD TRANSPORTATION CONFERENCE Andrew McLaughlin, PLS Craig Polifrone Dennis Hymel Jr., P.E.

2 Today s Topics Subsurface Utility Engineering (SUE) Quality Levels Quality Level B (Designation) Techniques, Suitability Quality Level A (Location) Utility Conflict Management and Mitigation Project Spotlight QL A, Conflict Mitigation

3 SUE Quality Levels Subsurface Utility Engineering (SUE) ASCE identifies utility mapping at standard Quality Levels. This standard is referred to as the CI/ASCE 38-02: Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data SUE is broken down into Quality Levels A, B, C, D Quality Level Attributes are attached to plotted utilities indicating how utility data was obtained Quality Levels define reliability and and has established a national standard of practice The purpose of SUE is to collect, gather, interpret, manage, and use utility information in accordance with standards

4 Level B Designation The instrument is just a transmitter and a receiver. Methods of Detection Using Radio Waves: Ground Penetrating Radar (GPR) Pipe and cable locators Electromagnetic Induction Methods of Detection Using Mechanical Waves: Acoustic Waves Water Waves Seismic Waves Other Methods: Magnetic Electrical Resistivity

5 Level B Designation Common Methods

6 Level B Designation Infrequent Methods

7 GPR Suitability in Louisiana Very little opportunity for success with Ground Penetrating Radar in Louisiana due to high levels of clay, silt and loam Only area where there might be some success is for lines recently installed that were trenched in.

8 Methods of Designating passive vs. active Active designating: Transmitter and Receiver Passive designating: Receiver Only

9 Passive Designating 60 Hz Electricity 120 Hz Cathodic Protection Signal Radio Frequencies Metal Detectors Dowsing

10 Active Designating Direct Connect = Best Results Strongest Signal Strength Most accurate designation technique

11 Active Designating: Signal Transmission 3 Methods - Direct Connection ( Clips ) - Inductive Coupling ( Clamp ) - Induction Box on the ground, or split box

12 How far you locate depends on several things Type of conductor - Coated better than non coated Diameter of conductor - Small better than large Quality of ground at each end Soil conditions Frequency of locator Power output

13 Determining Depth Continuous, push button, or triangulation. Measures to the center of pipe. The cleaner the signal, the more accurate the depth. No depth measurement is 100% accurate

14 Electronic Depth Estimation:

15 Signal Peaking above water main, no interference

16 Signal Peaking off target, Buried Telephone causing interference, designation inaccurate

17 Level B Deliverables Field Book,.DGN,.SHX, and more!

18 What is the only way to be 100% certain of a utility's location? Dig it up!!!

19 Level A Locating Level A is usually done by hydro or air excavation after the Level B survey in order to verify the xyz location of the utility. Vacuum excavation is a non-destructive process which combines highpressure air and/or water and a high flow of moving air to excavate soils and expose the utility. After the utility is exposed the depth, material, dimension and condition is documented by a detailed digital report with photos and incorporates the vertical and horizontal location of the utility into an existing survey.

20 Level A Locating Level A is usually done by hydro or air excavation after the Level B designation in order to verify the xyz location of the utility.

21 Emerging Technologies Augmented Reality TRMUA Program HoloLens Merges Field and Office Real-world Visualization of Design Conflicts

22 Case Study Project X New Two-Lane Rural Roadway 12 Travel lanes, 8 Shoulders 80 R/W width 3 Pipeline crossings o 20 Natural Gas o 12 Natural Gas o 10 Ethane Only Records Research performed w/ topo SUE Quality Level A performed in Final Design Utility conflict mitigation

23 Original Design (PL based on records)

24 Original Design (after Level A SUE)

25 Initial Conflict Mitigation Cost Estimates Vertical relocation of 12 Natural Gas PL 9 cover under roadside ditch Estimated cost $867,000 Included stopples for temporary shut down Split casing on 20 Natural Gas PL 15 cover under ditch, pipe stress analysis failed Estimated cost $259,000 Complete excavation of PL; casing and vents Total Conflict Mitigation Cost: $1,126,000

26 Conflict Management & Mitigation Subsurface Utility Engineers conducted additional site investigations, surveying, revised roadway design including vertical geometry and drainage

27 Final Conflict Mitigation Costs Concrete mat full width of RW atop 20 Natural Gas PL $134,800 Reinforced mat in roadside ditches atop 12 Natural Gas PL $52,819 Total conflict mitigation cost: $187,619 Cost of SUE & mitigation design: $47,250 Total mitigation costs to savings ratio: $4.79 Total savings: $891,131

28 Questions? Planning Environmental Surveying Engineering GIS/Mapping