Standard Cut vs. Keyhole

1 KEYHOLE TECHNOLOGY An O&M Infrastructure Management Tool For the 21 st Century Utility Micro-Surgery 2005 APWA International Public Works Congress and Exposition Tuesday, 13 September 2005 T. Mark Andraka---- Sr. Engineer Standard Cut vs. Keyhole 1.5 x 1.5 3 x 4 10 or 18 2 Small Hole Encapsulation Work 1980-1990 Vintage 3

4 Infrastructure Installations and Repairs made Safely Efficiently-- From above the hole Photo Credit Omega Servac Keyhole Opportunities Reduce Restoring Costs Coring Urban Microsurgery 2000 Plymouth Twp. Completion of GTI Reducing Excavation And Restoration Project Phase II 2001---GTI Keyhole Workshops Phoenix AZ & Hartford CT 2003 Ongoing---- GTI Keyhole RC Project 5 Pipeline & Gas Journal New Technologies, Close Coordination Save PECO Energy $1M August, 2002 Mark Andraka Brian Camfield Bill Hutton Allen Spivey 6

7 Enhancements to Vac Technology Resulting from Pilot Teamed with SerVac/Omega & GTI Trailer Vac Unit with Mobile Dump Valve Hose Assisted Unit One Man Soil Breakup and Vacuum Storage area for Pipehawk Air-Water Knife Standard Cut 3 X4 Excavation Excavate +/- pipe In-hole repair process Temporary black-top Cut-backs Separate Re-pave Contractor Dumping & Transportation Fees Up to 6 week time frame start to finish Keyhole 10 18 Excavation No need to excavate below pipe Above ground repair process Core reinstated-- No cut backs Homogeneous materials Can be performed year-round Minimal Impact to Traffic Flow and Public Job Complete prior to crew leaving site Standard Cut 8 Our Challenge Enhancement and Introduction of New Technologies into Operations Technologies accepted into work force The right technology for the right circumstance 9

10 THE PECO Energy Keyhole Technology Development Project A SerVac/Omega-GTI-PECO Coordinated Effort 2003-2004 Tools & Processes Excavations Core Hole No Cut-Back One Day Complete Job Micro-Excavation Locating Pin-pointing Leaks Facilities Less Time to Complete Job Less Customer Disruptions More Core Business with Less True Two-Person Team Complete --Start-Finish Pavement Coring Machines 6, 8, 10 or 18 Cores 11 Rotary Cutter for Cores-- Different Depths & Compositions Thin Asphalt Thick Asphalt Thick Composite and Reinforced Concrete 12

13 Core Reinstatement Backfill & Compact Grout Mixture Core Placement Finished Repair Excavation Tools Air Knife / Air Spade Water Jetter 14 Specialized O&M Tools Extended Handle w/detachable Tools 15

16 PECO Energy O&M Processes New and Replacement Services Installed 17 Anode and Test Station Installations 18

19 Curb Valve Installations > Credit collection > Safety 30 Minutes Later -- Open for Traffic! Completed repair almost invisible. No overnight road plating Restoration is traffic bearing in 30 minutes No return trips to make final restoration 20 What does this mean for the Road? - Improved Pavement Performance! Size Matters! Keyhole is 80% smaller than conventional utility cut -- more aesthetically pleasing with less damage to road system Precision core cutting avoids collateral damage to road -- no backhoes, jackhammers and over cuts from concrete saws No temporary patching. Replaced core exactly matches composition of original road Reinstates road to original weight bearing capacity 21

22 Post Job Process L Test Point Holes Core Hole Grout Line F (Direction of Traffic Flow) R CMT Cold Weather Process 23 Enhancements for Mainstream Location Location Location 24

25 A Solution A New Way to Undertake Our Infrastructure O& M Processes Inactive Gas Service Cut-offs Past Future

Soil Compaction Measuring Device Study Presented to APWA 2005 Conference - Daniel Vetter, P.E. Gas Technology Institute - GTI Tuesday 13 September 2005 Outline of Presentation Objectives Testing Program Tools Results & correlations Conclusions & Recommendations Objectives.. Provide the Inter-Agency with an evaluation of the currently available soil compaction measuring devices as an alternative to the Nuclear Density Gauge [NDG].

Objectives.. Why replace the NDG? Operator must be trained and licensed Company must have EPA approval Storage, transport and disposal of unit must be monitored Objectives.. Why replace the NDG? EPA initiative to investigate alternative devices FHWA research plans to develop alternative compaction control devices. Objectives.. Why replace the NDG? Not the best device in cuts. Readings near trench walls are affected by sidewall boundaries Offsets may be required.. if the material has concrete, some coal, and ferrous soils.. The gauge requires an offset if measurements are taken inside a trench Troxler Manual, model 3440

The Nuclear Density Gauge 60 % Increase in moisture content. 50 40 30 20 10 0 4-inch probe 8-inch probe 12-inch probe 0 5 10 15 Distance from side wall (inch) The Nuclear Density Gauge Keyhole Depth (inch) Moisture Content [%] 0 10 20 30 0 Sand Backfill 6 12 18 24 30 36 NDG Moisture Oven Moisture Soil Compaction-Measuring Devices Testing Program

Determine Backfill Properties 100 90 % Passing 80 70 60 50 40 NJ-Sand IL-Sand Silty-Clay Stone-Base 30 20 10 0 100.000 10.000 1.000 0.100 0.010 0.001 Sieve Opening (mm) Determine Compaction Properties Control Backfill Moisture in all Test layers In-Process Devices (Q/C) Soil Compaction Supervisor (SCS) Utility DCP GeoGauge Clegg Hammers

Post-Compaction Devices (Q/A) Standard DCP PANDA Meter These devices were evaluated with respect to the Control Devices: Nuclear Density Gauge Sand-Cone Apparatus and the Ag. Moisture Gauges Tests in Bellhole Sections

Tests in Trench Sections Tests in Keyhole Sections Soil Compaction Supervisor (SCS) Measurement Moisture Readings Calibration of Device Portability Durability ASTM Standard Operator skill Ease of use-training Max. Attainable Compaction (Pass/Fail) No Pre-set System Good Fair None Worker Easy Minimal training

Soil Compaction Supervisor (SCS) QC QA Application Data Storage Trench Boundary Keyhole Application Depth of Reading Surface Readings Output Consistency QC [continuous during compaction] Stores in memory (needs enhancement) No effect Yes Up to 30 inches N/A Good Utility DCP Measurement Moisture Readings Calibration of Device Portability Durability ASTM Standard Operator skill Ease of use-training Penetration (blow count) No No Good Good None Worker Easy Minimal training Utility DCP QC QA Application Data Storage Trench Boundary Keyhole Application Depth of Reading Surface Readings Output Consistency QC Manual recording No effect Needs extension rod Up to 8 inches Unreliable in top 3 in. in sand Fair

Utility DCP Soil Type Sand Silty-Clay Stone-Base Acceptance Criteria (*) 4-6 22 11 (*) - Acceptance Criteria is for 90% Modified Relative Compaction - Previous device calibrations in sand had acceptance criteria of 6 GeoGauge Measurement Moisture Readings Calibration of Device Portability Durability ASTM Standard Operator skill Ease of use-training Soil Stiffness & Young s Modules No calibration plate Good Good ASTM 6758 Worker Easy-Minimal training GeoGauge QC QA Application Data Storage Trench Boundary Keyhole Application Depth of Reading Surface Readings Output Consistency QC Stores Data affected by side wall No 9 inches as per manufacturer [not confirmed in tests] Sensitive to surface stiffness Fair

GeoGauge Soil Type Sand Silty-Clay Stone-Base Acceptance Criteria (*) 30 45 No correlation (*) - Acceptance Criteria is for 90% Modified Relative Compaction - Previous studies by FHWA showed acceptance values from 25 to 36 for A-3 and A-4 subgrade. Clegg Hammers Measurement Moisture Readings Calibration of Device Portability Durability ASTM Standard Operator skill Ease of use-training Clegg Impact Value (IV) No Factory calibrated Medium Poor ASTM D-5874 Worker Easy Minimal training Clegg Hammers QC QA Application Data Storage Trench Boundary Keyhole Application Depth of Reading Surface Readings Output Consistency QC Manual display No effect Yes About 8 inches Sensitive to surface stiffness Medium

Clegg Hammers Soil Type Sand Silty-Clay Stone-Base Clegg Hammer 10-Kg 6 8 14 Clegg Hammer 20-Kg 5 6 9 (*) - Acceptance Criteria is for 90% Modified Relative Compaction. - Previous studies on device presented a calibration with soil CBR ratio. Standard DCP Measurement Moisture Readings Calibration of Device Portability Durability ASTM Standard Operator skill Ease of use-training Penetration (blow count) No No Medium Good ASTM D-6951 Worker Easy-Require data plotting Standard DCP QC QA Application Data Storage Trench Boundary Keyhole Application Depth of Reading Surface Readings Output Consistency QA [Full depth] Manual recording (can be Automatic) No effect Yes Full depth (up to 3 ft) Not recommended for top 6 inches in sand Good

Standard DCP Soil Type Sand Silty-Clay Stone-Base Acceptance Criteria 1.1 blow/inch 5 blow/inch 2 blow/inch (*) - Acceptance Criteria for 90% Modified Relative Compaction - Previous studies by Mn-DOT in granular base recommended 0.75 inch/blow (1.33 blow/inch) The Panda Measurement Moisture Readings Calibration of Device Portability Durability ASTM Standard Operator skill Ease of use-training Tip Resistance & Penetration No Factory calibrated Medium Good (French Standard) Technician Extensive training The Panda QC QA Application Data Storage Trench Boundary Keyhole Application Depth of Reading Surface Readings Output Consistency QA [Full depth] Stores in memory No effect Yes Full depth (extension rods) Not recommended for top 6 inches in sand Good

Summary QC devices are the tools needed for layer-by-layer compaction control of restored utility cuts. The output of the devices provide a measure of soil densification. The acceptance criteria were determined based on for 90% Modified Compaction at optimum moisture contents. Summary Acceptance criteria can be achieved by controlling the moisture, lift thickness to 6-9 inches, and by using the appropriate compaction tools. The Utility DCP, the 10-kg Clegg Hammer, and the SCS were the three QC devices that had the best qualities for utility restoration work. Recommendations Utility DCP Improve drop height and handle design Add-on drop weight Storage and downloading capabilities Easy user interface for location information Add-on moisture measurement Handle extension for use in small-hole excavations

Recommendations Clegg Hammer Redesign of guide tube and improve cable connections Improve movability: Carrying case and cart Add storage and downloading capabilities Easy user interface for location information Add-on moisture measurement Handle extension for small-hole excavations Recommendations SCS Include numerical readout to define acceptance values Increase sensor depth range Add button and/or light for new holes Improve compactor type identification Modify data storage Easy user interface for location information Add-on moisture measurement capability Questions?