Encouraging Innovation in Locating and Characterizing Underground Utilities (2009)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

1Executive Summary Utility Issues in Transportation Projects Many of the extensive utility designating and locating procedures that are carried out during exca- vation for construction projects are intended to ensure public safety and prevent utility damage. It is also important, however, to fully identify the location and condition of all utilities early in the project planning and design process—preferably prior to excavation—to allow transportation projects to go forward with minimal delays and cost overruns. This early “locating” and charac- terization of utilities is best accomplished through better coordination with the transportation agencies with which utility companies often share the right-of-way space, through the implemen- tation of effective management policies; and, largely, through the use of emerging, powerful tech- nologies, which will be the focus of this report. Taken together, these elements comprise the subsurface utility engineering (SUE) framework. Coordination Between Transportation Agencies and Utility Companies Because the public transportation right-of-way is where nearly all buried utility systems are located, the planning, design, construction, maintenance, rehabilitation, and renewal of both transportation systems and utility systems are closely connected. Better information sharing and coordination between the owners of these two systems could accomplish a great deal. However, a companion SHRP 2 study (Project R15: Strategies for Integrating Utility and Transportation Agency Priorities in Renewal Projects) addresses this utility coordination process; this report focuses on technologies. Utility Locating Technologies The existence of a low-cost, easy-, and quick-to-use surface geophysical tool that identifies all util- ities during a planned-route field survey at any site regardless of soil conditions would remove most barriers to effectively managing utility issues in transportation projects. Unfortunately, such a technology does not exist. And the current technology used to locate buried utilities may be inef- fective at finding targets beneath the clutter of other utilities and buried objects or at significant depths in incompatible soil conditions, as is the case with electromagnetic locating equipment working in conductive soils. Trying to locate a fixed-location object by repeatedly employing various detection methods is clearly inefficient. Dealing with utility records that fail to incorporate quality assurance into the information shown on a set of plans or contained in a database is also problematic. However, rapid developments in utility marking and radio frequency tagging systems (RFID) and new technologies

2involving global positioning systems (GPS) and three-dimensional (3-D) geographical information systems (GIS) have changed what is technically possible in this regard. Together, these technologies allow for the development of accurate 3-D databases for newly installed utilities and for the rapid capture of accurate positional information when existing utilities are exposed. Even in ideal environmental conditions, however, cost and training issues limit the extensive use of existing technology. The transportation community faces the significant challenge of hav- ing to identify and assign cost to the real risks associated with not knowing whether a utility exists within the right-of-way (or proposed right-of-way) or, if one does, not fully knowing its location or characteristics. Faced with this challenge, a rational decision must be made on which tools to employ for a particular effort and an appropriate budget established to identify, locate, and char- acterize a utility. Utility Characterization Technologies “Utility characterization” describes the determination of a utility’s characteristics, with the excep- tion of its location. Characteristics might include the utility’s type, owner, size, material, age, pres- sure, voltage, capacity, condition, or activity status (that is, whether it is active, inactive, abandoned, or out-of-service). Unfortunately, there are few aspects of utility characterization data that can be reliably deter- mined from a surface-based utility location or characterization survey. However, this could change substantially with the introduction of utility smart-marking and tagging systems to iden- tify new utilities with programmable and updatable electronic markers and to mark existing util- ities as they are exposed for maintenance or during other excavation activities. Smart tagging systems together with utility companies’ ongoing asset management approaches offer the prospect of substantial improvement in managing the utilities that are located beneath rights-of-way. Targeting Improvements A national 14-member panel was asked to rank potential research initiatives for this report. The scored ranking of initiatives is shown in Table ES.1. The scores reflect consensus on the relative importance of the topics. However, the scores are relative and, thus, can best be interpreted by con- sidering them in relation to target-activity groupings with similar scores. Overall, greatest impor- tance was placed on storage, retrieval, and use of utility data and the development of multisensor platforms, followed closely by the development of guidelines. The second-highest priority was smart tagging, education and training, and locating deep utilities. The third-highest priority included detecting external voids, benchmarking current technologies, and deformation charac- terization technologies. The research team then developed project descriptions to be considered by the SHRP 2 committee for funding available through the appropriate SHRP 2 program area. Conclusions Although it is unlikely that technology to locate and characterize utilities will ever present a com- prehensive solution for all site conditions, it continues to evolve. And despite the significant administrative and legal hurdles that remain, implementing comprehensive utility mapping and marking of utilities and improving GIS-based utility databases containing SUE utility-quality des- ignations offers a significant and worthwhile advantage. Project owners can also mitigate utility- related challenges by effectively coordinating with transportation and utility agencies, realistically evaluating utility project risks and costs, and integrating policies, procedures, scopes of work, and utility field-investigation qualification and training requirements.

3Rank (Score) Topic, Description, and Benefits 1. (0.17) 2. (0.16) 3. (0.14) 4. (0.12) 5. (0.10) 6. (0.10) 7. (0.08) 8. (0.07) 9. (0.06) Topic: Storage, Retrieval, and Utilization of Utility Data Description: The development of dedicated software and hardware that would take advantage of recent advances in GPS and GIS technologies and increase the quality and efficiency of storing, retrieving, and utilizing utility records. Benefits: Increasingly comprehensive and accurate utility records, allowing resources to be focused on finding the remaining utilities. Topic: Multisensor Platforms Description: The development of multisensor platforms that combine two or more existing technologies [e.g., ground- penetrating radar (GPR) and electromagnetic (EM) location or GPR and acoustic approaches]. Benefits: More reliable performance for utility locating across a variety of soil conditions. Topic: Development of Guidelines Description: The development of guidelines and other tools for the conduct of utility investigations for transportation projects. Benefits: Allows transportation designers/planners to get the most out of the SUE data they receive so as to maximize the benefit/cost to the agency. Topic: Smart Tagging Description: Advances in hardware and software that support smart tagging (e.g., ball markers, RFIDs) and documentation of utilities during initial installation and when exposed during excavations for various purposes. Benefits: Improved in-field identification of utility location, type, and characteristics. Topic: Initiation of Education and Training Description: Initiation of educational, training, and dissemination activities aimed at increasing the awareness of transportation engineers and other decision makers to the state of the art and cost-benefit implications of gathering better utility infor- mation early in the design process. Benefits: Improved allocation and more effective use of utility locating expenditures. Topic: Location of Deep Utilities Description: The development of locating technologies that target deep utilities that currently cannot be detected by surface- based approaches. These could include direct-path detection methods deployed from inside a utility or cross-bore tech- niques based on vacuum-excavated boreholes. Benefits: Improvement in detection of the most difficult utilities to find from the surface and reduced impact of unlocated or mislocated deep utilities on transportation projects. Topic: External Soil Void Detection Technologies Description: The development of new technologies or enhancement of existing technologies capable of locating and characteriz- ing external soil voids from within a buried pipe or culvert. Benefits: Detection of future ground instability problems that can cause road settlement and sinkholes. Topic: Benchmarking of Current Technologies Description: The use of existing and/or purpose-constructed test facilities to systematically evaluate and document the capabili- ties and limitations of current utility locating equipment under controlled conditions of varying complexity. Benefits: Independent information on the capabilities of different types of detection equipment. Topic: Deformation Characterization Technologies Description: The development of new technologies or enhancement of existing technologies capable of characterizing the cross-sectional deformation of buried pipes and culverts over time. Benefits: Ability to track gradual deterioration of utilities constructed with ductile utility materials. Table ES.1. Research Topics as Ranked by National Panel