Subsurface Utility Engineering (SUE)

OVERVIEW What is Subsurface Utility Engineering (SUE)? Overview of SUE – Definitions When to Use SUE How to Use SUE Why Use SUE

What is Subsurface Utility Engineering? SUE

Subsurface Utility Engineering A branch of ENGINEERING PRACTICE that involves managing certain risks associated with: Utility Mapping at appropriate ASCE Quality Levels Utility Coordination Utility relocation and adjustment through conflict matrix resolution Utility relocation design and cost estimates Communication of utility data to concerned parties Implementation of Utility Accommodation Policies and utility design

SUE The project manager takes the first step to address subsurface-utility engineering by including it as a part of the design contract. The determination to use subsurface-utility engineering is a risk-management decision. The project manager will have evaluated the cost of subsurface-utility engineering against the potential cost of project delays due to unknown or unexpected locations of utility facilities during construction. The availability of funds within a contract does not imply a need for using full subsurface- utility engineering. Also, the absence of funds does not imply that subsurface-utility engineering is not needed. The designer and utility coordinator will further evaluate the quality levels necessary using subsurface-utility engineering during the development of the project. If SUE was not a part of the original RFP and the designer and utility coordinator determine that there is a need, they should work with the project manager to determine a method to include SUE in the project. FHWA will not participate in the cost of claims for construction delays due to utility relocation when SUE is not used.

SUE 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 38-02 contains the guidelines for collection and depiction of existing SUE data. It is currently going through a revision as well and will provide guidance on expanded deliverables; a sealed Utility Report by an Engineer; and an expanded cost-benefit section

SUE ASCE Standard – Quality Levels Quality Level D information is collected during the utility-research phase as required by 105 IAC 13-1-1. Also, Quality Level D information can be provided by the utility company in response to the initial notice letter. Obtaining Quality Level D information is addressed in Section 2.04. Quality Level C information is gathered during the project survey when all visible utility facilities are measured and recorded. Obtaining Quality Level C information is addressed in Section 2.04. Quality Level B information is obtained during the project survey. Facilities are located through Indiana 811 or by a SUE consultant. Facilities located through Indiana 811 have a hand-dig zone of ±2 ft from where the actual locate is marked. See Indiana Code 8-1-26 for further information concerning Indiana 811 and the accuracy of survey information. Facilities located by a SUE consultant are expected to be within ±3 in. of the mark. Quality Level A information can be collected during the design process by a SUE consultant where more-exact data is required at critical-conflict locations. Once preliminary drainage, structure locations, and right of way have been defined, the designer can determine the locations necessary to help with the evaluation of designing around utility conflicts. SUE ASCE Standard – Quality Levels The quality levels start with the base of records research (QLD) and increases with the information pertaining to the utility as you go all the way to QLA.

ASCE Quality Level D (QL-D) Existing Utility Records Involves the use of existing utility records, permits, plans to depict the ‘approximate’ horizontal position of underground utilities.

ASCE Quality Level C (QL-C) Survey of Visible Features Involves surveying visible above ground utility facilities to assist with determining ‘approximate’ horizontal position of underground utilities. Used with QL-D. Manholes Power poles Hydrants / valves Phone Pedestals

ASCE Quality Level B (QL-B) Utility Designating Involves the use of geophysical prospecting equipment to determine the existence and horizontal position of underground utilities. Paint markings Flags Field Sketch

Comments/ Notes/ Location Designating Approach: QA/QC All data is checked and cross-checked for accuracy – Records research vs. designating file Field sketch Designating data point & numbering system During the QA-QC process, point sheets are utilized to verify all the points on a particular facility have been collected Utility # of points Comments/ Notes/ Location W1 20 East side of road W2 4 West side of road W3 12 NB lane

One-Call is NOT Quality Level B

Why One-Call is NOT Quality Level B One-Call is a risk based system used for excavation One-Call Utility locator uses one piece of equipment No traffic control allowing necessary geophysical methods, or opening/investigating of utility structures The information received has no guarantee of reliability One-Call Utility locator has a narrow focus and limited by time Utility data records research, interpretation, and designation not performed under the responsible charge of a registered professional, no QA/QC performed

Quality Level B is... Using Appropriate Methods (Inductive vs Conductive) Inductive – inducing current along utility Conductive – directly connecting to utility Using Appropriate Equipment Single or multi-frequency electromagnetic units GPR Magnetics Sonde or sonic methods Supported by QL-D and QL-C Sealed by a Professional Engineer GPR

ASCE Quality Level A (QL-A) Utility Locating Involves the use of non-destructive digging equipment at critical points to determine the precise horizontal and vertical position of underground utilities, as well as the type, size, material, and other characteristics. QLA provides precise horizontal and vertical information at a specific point on a utility line by exposing the utility.

Locating Approach Permitting Minimal disturbance Saw cut in pavement Air vacuum excavation Centerline of facility Permanent reference points Proper restoration Compaction in 6” lifts Perma-Patch Vacuum excavation should be used specifically when performing holes in or near pavement so as to not compromise the integrity of the pavement subbase.

Locating Approach: QA/QC Test Hole Data Collection – A minimum of 4 photographs of every test hole for permanent record

Locating Approach: QA/QC Final QA/QC of all Subsurface Utility Engineering work is performed by the Field Lead on the project followed by a registered Professional Engineer

When to Use SUE? Type of Project Location of Project Piping and Facility Design (storm, sanitary, water) Site and Plant Design Roadway / Bridge const. Widening / Intersection Improvements Signal Replacement Location of Project Urban / Suburban Rural When to use SUE will be dependent upon the type of project and location of the project. If the project involves drainage design, with new curb & gutter and storm sewer, the conflicts may be great. In urban areas, the project may have an abundance of utilities, the project would be more prone to use SUE.

When to Use SUE? Utilities involved Conflicts with utilities Major or Minor Conflicts with utilities Compensable interest Limited Access R/W Accuracy required ASCE Quality Level? Level of Risk If the utilities involved are major, meaning high pressure gas lines or water lines that serve an entire city or town, or maybe the cost and schedule to move a particular facility will be excessive and will impact the project schedule adding 6-12 months to the schedule, SUE would be recommended. When to use SUE should be summarized by the need to look at the level of risk involved for the project by utility impacts and overall ‘It should fit the needs of the project.

What Are the Risks? Project delays Extra work orders Damage to utilities Safety of workers Safety of public Redesign costs Higher bids Change orders Extra work orders Construction claims Higher insurance / financing / construction costs Detours for travelling public Negative publicity

TOTAL ENGINEERING RISK POOL Risk Management TOTAL ENGINEERING RISK POOL ALLOCATION OF RISK WITHIN ENGINEERING POOL With no SUE your level of risk is great. As you provide additional quality levels, or an increased level of accuracy of your utility information, your (or your client’s) risk is minimized and potentially eliminated.

How Do We Use SUE? Commitment to avoid unnecessary utility relocations Communicate with Utilities early & often Records Research – QLD Utility Designating – QLB Topographic Survey – QLC Review of QLB, QLC & QLD Preliminary Design Utility Conflict Analysis Utility Locating – QLA Design Alternatives

Design Alternatives Geometric Alignment Change grade Shift alignment Widen on one side of the road Shift ramps or driveways Designers may change the grade to avoid a utility that may be under the pavement. Do you have the luxury of shifting a roadway alignment or only widening on one side of the road. R/W constraints may need to be looked at as well.

Design Alternatives Structure Design Alter footing / piling designs Provide alternative foundations Modify bridge layout Shift or modify retaining walls Add retaining walls Add guardrail When designing structures, look for alternatives to avoid utilities. Can the piling or footing design be altered to avoid a utility? Can it use MSE walls in lieu of a wall with a footing?

Design Alternatives Drainage Design Dual trunk line in lieu of single trunk Shift ditches Shift structure locations (inlets, pipes, manholes) Open vs. closed system Modify side slopes or ditch slopes Changes to drainage can often provide ways to avoid utility conflicts: use a dual trunk line in lieu of a single truck line; shift a ditch alignment; modify side slopes where possible. These are just some of the examples that designers should be looking at as they perform design to potentially avoid utility conflicts.

How Do We Use SUE? Utilities in Plan View How do we show SUE information in the plans. It starts in the Plan View. Properly show the utilities in Plan View (they have been colored here for ease of viewing). When test holes are performed, also provide the TH location in plan view. This particular project on 75th St. as part of the I-465 NE Leg Improvements, involved conflicts with 2 existing gas mains. The origin test al design called for a single trunk line and cross pipes perpendicular to 75th St. By performing holes at the conflict points on the gas and working with the designers to provide a dual truck line, we were able to eliminate the cross pipes and provide valuable information to CEG and they decided to keep the facilities in place. By performing $75,000 worth of SUE we avoided over $500K in relocations (a $6.67 return for every dollar spent on SUE)

How Do We Use SUE? Utilities in Profile View . Showing the test hole locations in Profile View will aid in revealing information about the conflicts.

How Do We Use SUE? Utilities in Cross Section View The Cross Sections can also show the utilities in horizontal view so you can visualize how the utilities lay as you progress up/down the project limits. This is a useful tool as well for determining conflicts with potential drainage structures and proposed cut and fill.

Why Use SUE? Make Informed Design Decisions Designers require accurate utility information, including constructability of multi-phase projects. Avoid Using Unreliable Underground Utility Information Avoid uncertainty and second guessing where a utility may be located.

Why Use SUE? Avoid Costly Conflicts / Utility Relocations By knowing the exact horizontal and vertical locations of underground utilities, costly conflicts and utility relocations may be avoided, along with not having to depend upon the utilities to relocate before construction can occur. Savings and Safety Inaccurate information can result in costly conflicts, utility damage, construction delays, service disruptions, redesign, claims, and even injuries and loss of life.

Relative Cost Savings & Benefits Purdue Study Commissioned by FHWA 71 projects studied in 4 states (VA, NC, OH, TX) Projects valued at >$1B SUE was < 0.5% of construction costs Both QLB & QLA performed

Relative Cost Savings & Benefits Purdue Study Cost savings of $4.62 per $1 spent on Subsurface Utility Engineering Largest return on investment was $208/$1 1.9% savings on construction costs Quantitative costs only (Qualitative costs not included) SUE is a viable practice that reduces project costs related to the risks associated with underground utilities If used properly it could result in a minimum savings of $1 billion per year

Relative Cost Savings & Benefits I-69 & 106th St. – New Interchange 23,300 lft of QLB and 120 test holes completed Utilities found crossing the interstate included a 20” water main in a 30” casing, a communication duct bank containing 8 to10 – 4” conduits, and a 20” sanitary sewer force main United PM stated, “We left two major utilities in place and under our new bridge foundations.  We would not have been able to even investigate such an option without reliable SUE, ultimately saving the project over $1,000,000 in utility relocation costs.” Cost savings of $6.45 per every $1 spent on SUE

SUE Current Practice Owner & Engineer Responsibility In an increasing number of states, lawyers and courts are using guidelines, agency policies, and contractual instruments to define and hold professionals accountable for their standards of care. It is an Engineer’s responsibility, on behalf of an Owner, to utilize all available resources and methods to gather and provide the most accurate information possible. As an engineer, they are professionals held accountable for their standard of care with respect to how they perform their duties and it is your responsibility to utilize all the available resources and methods to gather the most accurate information possible to properly design your project.

Subsurface Utility Engineering? Chapter 104