Advancements in Subsurface Utility Engineering and SurveyMichael Picha, PLS

February 20, 2020

Presented to:

Outline

• Introductions• History of Subsurface Utility

Engineering (SUE)• Management of Risk• Introduction of ASCE 38-02

– Definitions– Quality Levels - D, C, B, A– Deliverables

• Advanced Geophysics and Surveying– MCGPR– Manhole LiDAR

• 3D Modeling– 3rd Avenue Bridge

• Benefits of SUE– Risk Management

• Questions

Subsurface Utility Engineering in review

• 1982 – Traditional ways not working, SUE developed• 1985 – First statewide SUE contract with Virginia

Department of Transportation• 1986 – First statewide UC contract with Virginia

Department of Transportation• 1991 – FHWA began promoting SUE• 2002 – Standard ASCE 38-02 was adopted by

American Society of Civil Engineers• 2018 – 38+ State DOTs using Statewide\District-

Wide\Region-Wide UES Services

ASCE Standard 38-02

The American Society of Civil Engineers (ASCE) has developed a National Consensus Standard, CI/ASCE 38-02, titled “Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data”. This National Consensus Standard (NCS) is used by courts and lawyers, along with contractual instruments, to assist in both defining a professional’s standard of care and level of responsibility.

ASCE 38

• “The intent of this standard guideline is to present a system of classifying the quality of data associated with existing subsurface utilities.”ASCE 38-02

• “Such a classification will allow the project owner, engineer, constructor, and utility owner to develop strategies to reduce risk by improving the reliability of information on existing subsurface utilities in a defined manner.”ASCE 38-02

Project Risks without SUE

• Budget/Cost Estimate Overruns • Change orders• Damages• Disruption to the public• Legal issues• Negative Publicity• One call locates• Safety concerns• Schedules suffer• Redesign

ASCE 38-02 Definition of Subsurface Utility Engineering

DEFINITIONS• Subsurface Utility Engineering (SUE):

– A branch of engineering that involves managing certain risks– associated with utility mapping at appropriate quality levels …

Engineering - Geophysics - Surveying

Subsurface Utility Engineering Approach

Finding the Sweet Spot Through Engineering• Understand the Project Needs

– Type of Project– Budget

• Discuss the Available Methods• Analyze the Cost Benefit

Subsurface Utility Engineering Approach

Finding the Sweet Spot Through Engineering• No Two Projects are the Same• Differing Factors

– Available Methods– Available Budget

Every Project Will have an Acceptable Risk• It is the Consultant Engineer’s Job to Help

Determine the Acceptable Risk• The total risk for the engineering pool decreases

as quality level increases, While within the engineering pool, the risks shift towards the subsurface utility engineer as quality levels trend towards Quality Level A data.

What is Subsurface Utility Engineering?

ASCE Standard 38-02: Quality Levels

Least Certain Most Certain

Quality Level D Quality Level C Quality Level B Quality Level A

Subsurface Utility Engineering is an interpretive science; therefore, a skilled team with knowledge of construction history & years of experience sets us apart.

Utility Quality Level: • A professional opinion of the quality and reliability of utility information. Such

reliability is determined by the means and methods of the professional.– These levels are cumulative– Each QL is defined in the Standard

Definitions (from ASCE 38-02)

ASCE Quality Level D (QL-D)

Existing Utility Records• Information derived from existing records or oral

recollections. It is assigned when there is no other data other than records.− Record Drawings− As-built records− GIS Data

− Field Notes− DOT records− Circuit Diagrams

− Mtgs. w/ Staff− Land Owner− Valve Guides

ASCE Standard 38-02 - Quality Level “C”Topographic Survey

• Use of above ground surface features to indicate subsurface alignment, such as:– Valves– Fire hydrants– Pedestals– Manholes– Telephone pedestals

• Verified to ASCE Quality Level D records

Definitions (from ASCE 38-02)

Designating: The process of using a geophysical method or methods to interpret the presence of a subsurface utility and to mark its approximate horizontal position (its designation) on the ground surface.

Radio Frequency Pipe and Cable Locators

Single channel Cable Locator

ASCE Quality Level B (QL-B)- Designating

Determining the existence and approximate horizontal position of subsurface utilities.

Radio Frequency Pipe & Cable Locaters Single channel GPR

Part of our QA/QC process for QLB.

ASCE Standard 38-02 - Quality Level “B”

Utility Point Sheet and Sketch• This sheet references any paint marks

that are identified by geophysical methods • Periodically placed marks over the utility

identifies line position, critical bends, beginning and end of target lines.

• This process ensures that each paint mark has been captured when compared to the survey file and report.

• It’s important to have this systematic plan in place to ensure thorough recording of our findings.

Why is One-Call Information Not Quality Level-B?

• One-Call designed as a risk based system used for excavation• Typical One-Call locator uses one piece of equipment• The information received has no guarantee of accuracy• One-Call locator has a narrow focus/ limited time• Ghost signal/ signal jumps to another conductive source.• Rely on inaccurate utility records• Do not perform utility sweeps• Do not locate private utilities• No point sheet or sketch for accuracy• Survey of inaccurate paint marks is not QL-B• Utility data records research, interpretations, and designation

not performed under the responsible charge of a registered professional.

One-Call Information is Not Quality Level-B

“Reliable information has historically not always been provided by utility owners.” ASCE 38-02

What can happen when you are only marking one specific utility?

Buried ElectricBuried Water

Locators Marks

Because the electric line can carry a frequency better than the water, the water Locator’s equipment can “bleed off” onto the electric line without the Locator knowing since they are only locating a single line and the signal they have is good. The water

locator may not have any idea a buried electric line is in the area.

ASCE Quality Level A (QL-A) Locating

Utility Locating• Precise location by actual exposure• Minimally intrusive excavation method: A method of

excavation that minimizes the potential for damage to a structure being uncovered.

• Survey grade accuracy• Supported by QL-D, QL-C, and QL-B

ASCE Quality Level A (QL-A)

Gathering Appropriate Data• Surveyed information

– Horizontal and vertical location– Ground elevation

• Size and configuration– Pipe diameter / material– Width and height of duct banks

• Resolve differences in Quality Levels• Sign and seal by a licensed engineer

(ASCE 38-02; 4.1.12)

ASCE Standard 38-02 - Quality Level “A”

Test hole form• Information gathered from the test holes (type,

size, condition, material, and other characteristics) of underground utilities are provided on this form.

• Signed and sealed by a professional engineer.

ASCE Quality Level - A SUE DeliverableTest Hole Matrix

ASCE Quality Level - A SUE Deliverable

Why is SUE determined to be an engineering practice rather than a low-bid technology?

It is…• an engineering practice• classification of utility data in accordance with ASCE38-02• creates common language between all stakeholders to make informed decisions and reduce risk• marks all utilities• searches for non-recorded and abandoned utilities• assumes responsibility for missing or erroneous marks• sealed by a licensed professional• is performed under a qualifications-based contract

It is NOT…• Survey of Gopher State One-Call Marks• CAD File Depiction of Utility Information of Unknown Origin

Advanced Geophysics

STREAM CSingle-channel GPR

Stream EM MCGPR

3D Multi-channel GPRField Collection

Single-channel GPR

Looking to the Future - Advanced Geophysics

3D Multi-channel GPR Results

Leica BLK360 Lidar

Leica BLK360 Lidar Image

Time To Take Action• Utility Corridors will continue to get more congested.• The Importance of Accurate Reliable Information will increase as will the use of 3D Models.• Experienced Utility Coordinators will become increasingly important roles on design projects.

3D Project Highlight – TH 65 (3rd Ave) Bridge, Minneapolis

• MnDOT Project• Opened 1918• Rehabbed 1979-1980• Current scope includes

– Replacement of Deck– Repair piers, arch ribs and

barrel arches.– Replace Spandrel Columns– Addition of bike lanes.– Regrading of approaches

Image by MnDOT

Why SUE? - TH 65 (3rd Ave) Bridge, Minneapolis

• Dense volume of facilities in Minneapolis.– Approaches and intersections.– Unknowns

• 36” Water Main affixed to bridge.• 30-way conduit pack affixed to bridge• Construction Staging

– Temporary crane locations– River barge spud locations

SUE – Benefits summary

• “When subsurface utilities are discovered during the construction phase, the costs of conflict resolution and the potential for catastrophic damages are at their highest.”ASCE 38-02

• “That is why the collection and systematic depiction of reliable data for existing subsurface utilities is critical if engineers are to make informed decisions and support risk management protocols regarding a project's impact on these utilities.”ASCE 38-02

SUE – Benefits summary

• Accuracy of information during planning phase

• Clearly define conflicts and relocations – NO SUPRISES

• Reduce redesign cost• Reduce project cost• Reduce delays• Improve safety• MANAGE RISK!

SUE is used on a variety of projects

• Airports & Seaports• Asset Management• Hospitals & Medical Facilities• Power Plants• Public Works• Railroad / Rapid transit• University campuses• Utility Facilities• Wastewater Treatment Plants

Where to use SUE on projects

Project Planning

30% Design

70% Design

90% Design

Final Design and Construction

QL-D QL-C

QL-B

QL-A

Additional QL-A

Utility Coordination

DESIGNENGINEER

Without SUE With SUE

TOTAL RISK

RISK ELIMINATED

SUEENGINEER

D C B ADEFINED QUALITY LEVELUNDEFINED QUALITY LEVEL

TOTAL ENGINEERING RISK POOL ALLOCATION OF RISK WITHIN ENGINEERING POOL

Total Risk

The total risk for the engineering pool decreases as quality level increases, While within the engineering pool, the risks shift towards the subsurface utility

engineer as quality levels trend towards Quality Level A data.

Thank You

There are more difficult things to deal with on the job than utilities!

Michael A. Picha, PLS7157 Commerce Circle WFridley, MN 55432Office: (763) 203-6170 | Mobile: (612) 214-3153Michael.Picha@T2ue.com

Additional Information