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Subsurface Utility Engineering is a process for accurately identifying the quality of subsurface utility information needed for project planning design and construction, and for acquiring and managing that level of information during the development of a project. Underground utilities of interest include the following: Communication Cables; Gas, Petroleum and Propane Lines; Sanitary and Storm Sewers; Electric Power Lines; and Water Lines, etc. Traditionally, information concerning location of underground utilities during project planning stage is obtained from sources such as old project plans and utility records (As-Designed or As-Built). The reliability of the information is sometimes questionable and the accuracy cannot be verified. This can be attributed to a number of factors including the fact that there is no centralized record storage, no standard recording format and, most importantly, no one is responsible for the accuracy of the information even if it is available. In order to overcome some of these problems, the methodical process of SUE is being used in all stages of project planning, design and construction. SUE combines traditional engineering practices such as utility records research and plotting of such information with data obtained using relatively new technologies including geophysical methods and air pressure vacuum exposure. The American Society of Civil Engineers (ASCE) has developed an important standard of care guideline, Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data, CI/ASCE 38-02. This standard guideline describes four quality levels of utility depiction: Quality Level D - Information derived from existing records or oral recollections. Quality Level C - Information obtained by surveying and plotting visible above-ground utility features and by using professional judgment in correlating this information to Quality Level D. Quality Level B - Information obtained through the application of appropriate surface geophysical methods to determine the existence and approximate horizontal position of subsurface utilities. Quality Level A - Precise horizontal and vertical location of utilities obtained by the actual exposure and subsequent measurement of subsurface utilities, usually at a specific point. KMA performs all these levels. Equipment
A wide range of equipment is necessary to detect the variety of subsurface
utilities that may be present. Equipment available for utilization by KMA
include, but not be limited to, state-of-the-art designating equipment; vacuum
excavation, state-of-the-art surveying and data recording equipment; and
software systems compatible with those of the contracting agency. Major SUE Activities Scope of Work - The process consists of developing a written project-specific work plan package that consists of scope of work, levels of service vs. risk allocation, project schedule and desired project delivery method. This SUE work plan package requires the approval of the client. Designating - The process of using a surface geophysical method or methods to interpret the presence of a subsurface utility and mark its horizontal position on the ground surface or on above-ground surface markers. Locating - The process of exposing and recording the precise vertical and horizontal location and providing utility size and configuration of a utility. Data Management - The process of surveying, designating, and locating information to project control and transferring it into the client's CADD system, GIS files, or project plans.
Conflict Analysis - The engineering process consists of using a conflict matrix
to evaluate and compare depicted designating information with proposed plans
(highway, bridge, drainage, etc) in order to inform all stakeholders of
potential conflicts, potential resolutions and costs of solutions. The Benefits of SUE Subsurface utility engineering Subsurface utility engineering benefits both highway agencies and utilities in the following ways: 1. Unexpected conflicts with utilities are eliminated. The exact location of virtually all utilities is known and accurately shown on the construction plans. 2. Reduces delays caused by redesign when construction cannot follow the original design due to utility conflicts. 3. Reduces delays to the contractor during highway construction caused by cutting, damaging, or discovering utility lines that were not known to be there. 4. Reduces subsequent contractor claims for delays resulting from unexpected encounters with utilities. 5. Unnecessary utility relocations are avoided. Accurate utility information is available to the highway designers early enough in the development of a project to design around many potential conflicts. This significantly: 6. Reduces costly relocations normally necessitated by highway construction projects. 7. Reduces delays to the project caused by waiting for utility work to be completed so highway construction can begin. 8. Safety is enhanced. When excavation or grading work can be shifted away from existing utilities, there is less possibility of damage to a utility that might result in personal injury, property damage and releases of product into the environment. Subsurface Utility Engineering is not confined to highways. It can be used with good results on airport, railroad, transit, building construction, military, sanitation, nuclear, and any other public works project where underground utilities may be encountered. It can also be used for environmental purposes, such as detecting and mapping underground storage tanks, septic fields, and even contaminants. SUE adds value, quality, and accountability to any project
United States Department of Transportation - Federal Highway Administration (FHWA)
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1. Clear the test hole area of surface debris. 2. In paved areas, neatly cut and remove existing pavement, which cut shall not exceed 225 square inches (0.15 square meters) unless otherwise approved. 3. Excavate the test hole by the method(s) acceptable to DOT and to the standards set forth herein (see also "Selection of Method" above). The nominal diameter of the test hole shall not exceed 15 inches (375 mm) unless otherwise approved. 4. Expose the utility only to the extent required for identification and data collection purposes. 5. Avoid damage to lines, wrappings, coatings, cathodic protection or other protective coverings and features. 6. Hand-dig as needed to supplement mechanical excavation and to ensure safety. 7. Revise the test holes location as necessary to positively expose the utility. 8. Store excavated material for re-use or disposal, as appropriate. Collection, Recording, and Presentation of Data 1. Measure and/or record the following information on an appropriately formatted test hole data sheet that has been sealed and dated by the Consultant: 2. Elevation of top and/or bottom of the utility tied to the project datum, to a vertical accuracy of +/- 0.05 feet (15 mm). 3. Elevation of existing grade over utility at test hole. 4. Horizontal location referenced to project coordinate datum, to a horizontal accuracy consistent with applicable DOT survey standards. 5. Field sketch showing horizontal location referenced to a minimum of three (3) swing ties to physical structures existing in the field and shown on the project plans. 6. Approximate centerline bearing of utility line. 7. Outside diameter of pipe, width of duct banks, and configuration of non-encased multi-conduit systems. 8. Utility structure material composition, when reasonably ascertainable. 9. Identity of benchmarks used to determine elevations. 10. Utility facility condition. 11. Pavement thickness and type when applicable. 12. Soil type and site conditions. 13. Identity of utility owner/operator. 14. Other pertinent information as is reasonably ascertainable from test hole.
1. Replace bedding material around exposed utility lines in accordance with owner's specifications or as otherwise directed or approved. 2. Backfill and compact the excavation in a manner acceptable to DOT. If approved, re-use excavated material with appropriate moisture/density control. 3. Install color-coded warning ribbon within the backfill area and directly above the utility line. 4. As applicable, provide permanent pavement restoration within the limits of the original cut using materials, compaction, and pavement thickness acceptable to DOT. 5. Repair or replace backfill or pavement that fails 6. For excavations in unpaved areas, restore disturbed area as nearly as practicable to pre-existing conditions. 7. Furnish and install permanent surface marker (e.g., P.K. nail, peg, steel pin, or hub) directly above the centerline of the structure and record the elevation of the marker.
1. Exercise professional judgment to correlate data from different sources, and to resolve conflicting information. 2. Update plan/profile sheets, electronic files, and/or other documents to reflect the integration of QL D, QL C, QL B, and QL A information. 3. Recommend follow-up investigations (e.g., additional surveys, consultation with utility owners, etc.) as may be needed to further resolve discrepancies. 4. As appropriate, amend the indicated quality level of depicted information.
To learn more about SUE and FHWA requirement visit web site at: http://www.fhwa.dot.gov/programadmin/sueindex.htm
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Copyright © 2009 KMA, INC.
KMA Consulting Engineers, Inc. 1010 Berlin Road, Cherry Hill,
NJ 08034 Phone: (856)
428-3600 FAX: (856) 428-3606 Email:
info@kmapc.net
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