Encouraging Innovation in Locating and Characterizing Underground Utilities (2009)

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114A P P E N D I X B Case HistoriesThe following case studies were obtained through discussion with practicing professionals, a literature search, a survey of subsurface utility engineering (SUE) projects conducted by the TBE Group Inc., and a research report released by the University of Toronto. These cases represent successful appli- cations of SUE technologies and practices in a variety of transportation-related projects. In addition, several nontrans- portation-related projects that had data available on the rela- tive cost of the SUE effort and the estimated benefit-to-cost ratio, or both, are also briefly described. Case Study No. 1: Service Road 167, Renton, Washington, 1998 In the late 1990s the Washington Department of Transporta- tion undertook a series of culvert replacement projects along Service Road (SR) 167, a four-lane highway paralleling the Pacific coastline. The objective was to support the upstream migration of salmon in local tributaries for conservation purposes. The project called for the installation of a 6-ft diameter, 200-ft long culvert using trenchless technology. The crossing was to take place where the elevated highway traverses a floodplain. When building the highway, the con- tractor used whatever was locally available as fill material, including tree trunks, boulders, concrete blocks, and old rail cars. A similar project conducted a year earlier some distance north, near the town of Everett, resulted in significant con- struction delays, cost overruns, and claims when the micro- tunneling boring machine (MTBM) encountered various obstacles immediately below the road surface. The MTBM got jammed and required the initiation of a costly recovery operation using a pipe-jacking technique. To avoid a repeat of such difficulties, an innovative subsurface utility engineer- ing investigation was developed and executed. The investi- gation consisted of three bores directionally drilled across the highway. One of these bores was located along the pro- posed centerline of the new culvert, while the other two wereplaced 6 ft north and south of it. A 4-in. polyethylene con- duit was installed in each of the bores. A suite of geophysical tools, including borehole ground-penetrating radar, induc- tion, gamma, and seismic technologies were used to conduct out-of-pipe and cross-bore studies. The results from the studies conducted at the different points were correlated with each other and with observations made at locations along the bores where obstacles were encountered during the horizontal directional drilling (HDD). Twenty-one possible targets were identified along the proposed centerline, com- pared with only six along the alignment 6 ft to the south of it. Subsequently, the culvert alignment was moved 6 ft south- wards, and the project was completed uneventfully using pipe ramming. Case Study No. 2: Hartsfield- Jackson, Atlanta, Georgia, Airport Infrastructure Electronic Marking, May 2006 Hartsfield-Jackson Atlanta is the world’s busiest passenger airport, serving more than 89 million passengers in 2005. To expand the airport capacity, a new 9,000-ft runway was con- structed and officially commissioned in May 2006. As new cables were buried parallel to the new runway, about 1,000 dis- crete locations were electronically marked to support routine maintenance activities and future construction work. Typi- cally, buried utilities at airports are marked using 2-ft × 2-ft × 6-in. concrete markers flush with the ground, which are placed immediately above marked features. Such physical markers are costly (about $100 a piece) and require ongoing maintenance, such as painting and grass removal. Also, they are susceptible to unintentional displacement by moving equipment and soil erosion, which can compromise excavation accuracy. Locating the buried utilities is accomplished using multifrequency electromagnetic cable locators. While it is effective for tracing an individual metallic cable, ambiguous results could arise when there are multiple utilities in close proximity.

115To overcome these shortcomings, the Federal Aviation Administration (FAA) adopted an innovative radio frequency identifiers (RFID) buried-marker technology that has low vul- nerability to moving equipment, requires no maintenance, and provides precise locating information. These RFID sensors act as passive antennas, reflecting back the query signal from the locator without requiring an internal power source. Interroga- tion is accomplished from the surface using a locating device. The information preencoded in the markers can range from the markers’ exact coordinates to the diameter and material of the buried utility or utilities beneath it. Another advantage of RFID buried-marker technology is the relative ease of dis- tinguishing among multiple adjacent buried utilities. The marking system selected for the project consisted of 4-in. round ball markers (3M Dynatel 2200MiD Series), each containing a unique and remotely readable identification num- ber. Each marker can be programmed with custom script that includes the purpose and composition of the buried utility, its coordinates, and its depth below grade. An operator scripts each ball using a portable locating device and places it in the trench as utility installation progresses. In the Atlanta project, markers were placed at 200-ft intervals for straight sections and at shorter intervals at turn points and in congested areas. Each utility was marked on both sides of all road crossings. The marker locator used a GPS feature that automatically collects GPS coordinates for markers as they are buried. GPS informa- tion was then transferred to the mapping database along with a marker identification number and other relevant information, allowing for the creation of an electronic as-built map in a geographic information system (GIS) format for ease of use in future construction planning and maintenance operations. Case Study No. 3: Urban Electrical Duct Bank Relocation, Orlando, Florida The Orlando Utilities Commission sought to redesign their electrical duct bank system in downtown Orlando. This redesign was made particularly complex by the region’s urban environment and the redesigning of Interstate 4 and the State Road 408 Interchange, two major limited-access highways in central Florida. The SUE consultant was assigned the task of locating and identifying underground facilities. The investiga- tion successfully identified not only known facilities but several utilities for which records were not provided. The design and construction processes were performed and executed smoothly. Case Study No. 4: I-70 Fast Track, Indianapolis, Indiana To avoid utility delays that will negatively affect the project’s demanding schedule, Indiana DOT (INDOT) regularly uses SUE to identify and coordinate utility impacts and reloca-tions. Examples of this practice are the I-70 Fast Track and Super 70 projects in Indianapolis and the I-74/US 421 road- way improvements for a new Honda plant in Greensburg. The INDOT I-70 Fast Track project involved reconstruction to accommodate expansion of the Indianapolis Airport, including relocating and lowering a 2.3-mile section of inter- state I-70 by 20 ft. To meet tight scheduling demands, test holes and utility designations were made within the first month. In addition, proactive utility coordination efforts were initiated to support the aggressive fast-track schedule. The project went forward with minimal utility disturbance- related issues. Case Study No. 5: Utility Composite Plans Assessment, Dulles, Virginia Dulles Transit Partners hired a SUE firm to assess utility com- posite plans compiled using as-built data for the Dulles Metro- rail Extension Project in the Tysons Corner area of Fairfax County, Virginia. Records included one-call marks, as-built drawings, facility maps, and design plans. The SUE investiga- tion, which employed electromagnetic equipment to confirm the record, discovered many misreported or unknown utilities. Consequently, the owner decided to expand the SUE investiga- tion to the entire project area. Findings from the SUE investiga- tion helped to avoid significant construction-related impacts associated with unmarked or mismarked utilities, and the proj- ect was completed without a serious incident. Fairfax County started using SUE in 1980 in an effort to reduce construction expenses caused by unexpected utility hits, redesign costs, and contractor claims. Using SUE during project design has dra- matically reduced the number of utility conflicts. Case Study No. 6: Hamilton, Ontario, Canada, 2002 A SUE investigation was completed as part of the design phase of a major streetscape/water main/sewer project in downtown Hamilton, Ontario, Canada. The project involved the installation, reconstruction, and replacement of munici- pal utilities in the area and major streetscape enhancements to improve the overall aesthetics of the downtown area. The study included the collection of utility records that were the basis for more than 10,000 ft of utility designating (quality level B) that was conducted using electromagnetic cable- located equipment. The work also included 25 test holes (quality level A) installed to confirm the exact depth and size of pipes in critical locations. The information derived from the study was used to support the design of the utility align- ments. The data from the SUE study identified several con- flicts because of erroneous or missing records. Specifically, a

116large unmarked underground hydro tunnel was found to cross the proposed alignment of the new water main. Among the other unmarked utilities that were identified and that had potential to cause construction delays and cost increases were abandoned gas mains and a phone duct structure. In addi- tion, exact location and characterization information was provided on other utilities for which records were incom- plete. A study conducted by the University of Toronto sug- gested that the City of Hamilton enjoyed a savings of about $282,000 because of the SUE investigation, yielding a benefit- to-cost ratio of 6.6:1. The cost of the SUE investigation was $42,785 and amounted to about 1% of the total project cost. Case Study No. 7: I-75 Water and Sewer Main Relocation, Georgia The Georgia Department of Transportation (GDOT) was preparing to relocate a water and sewer main from a rest area parallel to I-75. GDOT hired a SUE consultant to provide utility information for the project. GDOT believed that con- flicts existed between newly proposed utility services and the existing utility lines in the right-of-way. A quality level B study and a subsequent quality level A investigation involving exca- vation of test holes revealed that no conflict existed at the crit- ical sections. The utilities were not relocated, resulting in a savings of thousands of dollars. Case Study No. 8: State Highway 130, Preconstruction SUE Investigation, Texas A SUE investigation was undertaken as part of the precon- struction phase of State Highway 130, a major design-build transportation project involving a four-lane highway, toll facilities, and major interchanges. The design called for the relocation of many utilities and the construction of new util- ities needed to support the toll roadway. The SUE firm desig- nated about 1.5 million linear feet and excavated more than 600 test holes. Based on the SUE information the road design- ers revised their plans, shifting the right-of-way by about 300 ft to avoid the relocation of several high-pressure pipelines. This change prevented project delays and resulted in savings estimated at $3 million. Case Study No. 9: Utility Investigative Survey, Kitchener, Ontario, Canada The first SUE pilot project initiated by the Ontario Ministry of Transportation (MTO) took place at the Homer Watson Boulevard and Highway 401 interchange, at the city of Kitchener-Waterloo. The project involved the reconstructionof the Homer Watson interchange with Highway 401 and included the following activities: bridge reconstruction, lane widening, modifications to existing ramp alignments, and the construction of new ramps. At the time of data collection, design was about 30% completed. Utility-records information served as the basis for the designation (quality level B) that was performed using multifrequency electromagnetic cable- locating equipment in zones where the new ramps were to be constructed. A number of potential conflicts were identified and 16 test holes (quality level A) were made to confirm the vertical depth and characteristics of selected utilities at criti- cal locations. A number of unmarked underground utilities were located, including a fiber-optics line located at the same location where the formation of the bridge was to be installed. Based on data provided by the SUE investigation, designers decided to lower several utilities that were in grade conflict with the excavations for the proposed ramp. The SUE investigation cost $25,000. A study by the University of Toronto suggests that MTO saved more than $62,000 because of the subsurface investigation, which translates into a return on investment of $2.48 for each dollar spent. The cost of the SUE investigation amounted to 0.125% of the overall project budget. Case Study No. 10: Design-Build Bridge Project, South Carolina A contractor on a design-build bridge project needed to determine the exact locations of a water main and a sewer main that had been bored deep beneath a local swamp and river and that served a local educational facility. An innova- tive SUE approach was used to locate the exact positions of the mains beneath the water surface. The consultant shut and pumped down the mains on a national holiday, so that electro- magnetic sound could be pulled through the pipes. Using a receiver on the surface, the exact location of the deep utilities was determined. Based on the information provided, the con- tractor completed the design and construction of the bridge pilings while avoiding the utilities. Case Study No. 11: Street Reconstruction, Oshawa, Ontario, Canada The municipality of Durham sought to engage in a full- depth reconstruction of the four-lane Ritson Road in Oshawa, Ontario, because of deteriorating pavement conditions. The municipality elected to use the opportunity to renew an existing water main and construct a separate storm-water collection system. Previous incidents involving inaccurate underground utilities information and the age of the area’s infrastructure increased the likelihood of inaccurate or incomplete utility records, so it was decided to conduct a

117comprehensive SUE investigation. A quality level B desig- nated investigation was conducted along the proposed align- ment for designating gas, electrical, and telecommunications utilities. Forty-three test holes were made to confirm the des- ignation and provide the exact depth of utilities at critical locations. The information collected by the SUE investigation was compared with that provided by owners of the various utilities. A critical discrepancy was identified that involved a thought-to-be-in-conflict gas main that was found to be 8 ft away from the location indicated by the utility’s records. Consequently, the relocation of the gas main was canceled, as no conflict existed with the planned waterline. In addition, several other inaccuracies in the as-built drawings were detected and corrected, eliminating potential conflicts and subsequent claims. The cost of the SUE investigation was $91,000, or about 2% of the project’s total cost. The return on investment for the investigation was estimated by the Univer- sity of Toronto’s research team to be 2.1:1. Case Study No. 12: Street Reconstruction, York, Ontario, Canada A utility project involved constructing a 3-mi long, 42-in./ 30-in. diameter, pre-cast concrete feeder main along Major Mackenzie Drive in York, Ontario, at a projected cost of $8 million. Funding for the SUE investigation was justified by claims in previous projects that arose from inaccurate utility information as well as from the nature of the project, which called for pre-cast concrete pipe. This pipe type has lead to limited flexibility, as all bends and chambers are pre-fabricated in the plant and shipped to the site. Thus, field modifications are costly because elements must be reordered with the new dimensions and configurations, resulting in extra construc- tion costs and delays. SUE was used at the point at which about 30% of the design was completed. At the time, a pre- liminary route had been selected based on known data. The SUE investigation revealed several unmarked abundant util- ities. In addition, several potential conflicts with poorly marked traffic control and electrical utilities were identified. The accurate location of existing utilities and the identifica- tion of several unmarked pipes and conduits resulted in changes in the route and in the grade of the new pipe to avoid these conflicts. For example, as a result of the information provided, they were able to avoid placing the new pipe beneath an 18-ft deep sewer force main, a costly and risky task because of the deteriorated structural condition of the force main. The investigation included about 30,000 linear ft of utility designation and five test holes, at a cost of $20,000, or about 0.25% of the project total cost. A study by the University of Toronto placed a benefit-to-cost ratio of about 3.9:1 for the SUE component of the project.Case Study No. 13: Weston Rd./Walsh Ave., Toronto, Canada A new 16-in. PVC water main was to be constructed to replace an existing 6-in. steel main that was nearing the end of its service life. When the design was about 60% com- pleted, a SUE investigation was initiated. The study included quality level C verification of maps and records, and 6,000 ft of quality level B designation. Thirteen test holes were exca- vated at critical locations along the proposed alignment. The SUE’s main findings had to do with a 12-in. steel gas main that was found to be nearly 2 ft off its marked location along the north side of Weston Road, as well as an unmarked 12-in. steel gas main branch serving properties on the street’s south side that were in direct conflict with the proposed alignment. Based on data provided by the SUE investigation, the route of the water main was moved from the south to the north side of the street, resulting in significant savings from shorter service connections and reduced pavement restora- tion requirements. In addition, several unmarked electrical ducts and a storm sewer were located, and their locations were incorporated into the design. The cost of the SUE inves- tigation was $31,000, while the savings associated with elim- ination of construction delays and reduced pavement restoration costs were estimated by a University of Toronto study to be just over $100,000, yielding a benefit-to-cost ratio of about 3.25:1. Case Study No. 14: Richmond Hill, Ontario, Canada A 12-in. diameter, 2,000-ft long water main was to be con- structed along Dunlop Street in the town of Richmond Hill. The town requested a SUE investigation late into the design process after other projects brought to light utility misin- formation in its records and the potential adverse impacts in terms of contractor claims and schedule delays. For example, in a similar water main replacement project, a $55,000 cost overrun was incurred on a $675,000 project. The SUE investigation included nearly 10,000 ft of utility designation and three test holes. The investigation’s main finding was that telecommunication cables shown to be under the sidewalk were found to be 7.5 ft into the road- way. Because the SUE investigation was conducted when design was 90% completed, substantial redesign was required to accommodate the investigation’s findings. Specifically, the city required the owner of the telecommunication cables to relocate them at the utility’s expense, saving the city $50,000, which was the expected cost to relocate 150 ft of a 12-in. gas main that was called for in the original design. The cost of the SUE investigation added about 2% to the total project cost.

118Case Study No. 15: London, Ontario, Canada A new sanitary sewer system was needed to replace a 60-year old combined sanitary/storm system beneath King Street in downtown London, a major city in southern Ontario. The city’s records for this area were very old and based mainly on utility information compiled in 1966. An earlier project con- ducted in the mid 1990s in the same part of the downtown core was abandoned after numerous conflicts with existing utilities were encountered during construction, resulting in no return for an investment of $80,000. To avoid a similar sit- uation, the city decided to conduct an extensive SUE investi- gation early on, when the design process was about 30% completed. The SUE investigation included designating 6,600 ft of telecommunication, gas, electrical, water, sewer, and steam utilities as well as 19 test holes. The SUE provider sup- plied the design team with detailed drawings of the location and width of existing utilities, some of which were known to exist, but the locations of which were unknown, while records for others were completely missing, particularly those related to service connections. Also, the in-service or abandoned sta- tus of the utilities was determined, easing the process of get- ting utility owners to remove or relocate their lines. The main finding was that steam pipes used for heating city facilities were in direct conflict with the proposed sewer line. Neither the city nor the steam company had records of the location of these pipes. Based on data provided by the SUE investigation, it was determined that the preliminary design was not feasi- ble, and a complete redesign was required. Consequently, construction was postponed for two years because of restric- tions in the downtown core that permit excavation work every other year. The cost of the SUE study was $40,000, while a conservative estimate of the savings to the city, according to the University of Toronto, came to just below $80,000, a return on investment of about 2.0:1. Case Study No. 16: Street Reconstruction, Richmond Hill, Ontario Richmond Hill is a fast-growing community near Toronto, Ontario. To support its rapid residential development, plans were drawn to convert Hall Street, a rural roadway with drainage ditches into a curb-and-gutter cross section. The plan also called for removal of the drainage ditches. Due to previous successes with SUE technology, the town decided to consider using SUE on all projects in which there is significant potential for conflict with existing utilities. The SUE study revealed that a gas main marked to be 6 ft off the curb was actually located inside the roadway and thus required reloca- tion before the transportation project commenced. The costof the SUE study was $11,000, and the estimated return on investment associated with the SUE investigation was 3.0:1. Case Study No. 17: York, Ontario, Canada The York Durham Trunk Sanitary Sewer was reaching its design capacity, and it was decided as a short-term solution to construct a bypass sanitary sewer to parallel the existing line, tying into the North Don Collector Trunk. The area is highly developed and is served by a dense network of buried utilities. Furthermore, the design team had little flexibility due to the need to accommodate existing inverts of the upstream and downstream connections and several known crossings by other on-grade sewer lines. The consultant per- formed SUE quality level D and C investigations and hired a specialized subcontractor to perform quality level B and A studies at critical locations. The SUE investigation was con- ducted when design was 30% completed. All utilities within the right-of-way of the proposed sewer bypass were desig- nated, along with 39 test holes constructed to confirm the accurate utility depth at locations of potential conflict. The main finding was that a 16-in. sewer that crossed the proposed line was 8-in. deeper than originally indicated by the records, eliminating the need for its relocation. The SUE study cost $62,000 and resulted in an estimated saving of $123,000, according to a University of Toronto estimate, or a benefit- cost ratio of about 2:1. Case Study No. 18: Locating a 69 kV Electric Power Line Underneath the St. John’s River, Jacksonville, Florida Jacksonville Electric Authority (JEA) owns a 69 kV electric power distribution line that crosses under the riverbed floor of the St. John’s River in Jacksonville, Florida. Rehabilitation work was being performed along the shore of the river water- front. As part of this work, a new seawall was to be constructed. The engineering firm performing the construction hired a SUE company to locate the depth and position of the high-voltage line along the north shore so that they could avoid hitting the line when placing the metal-sheet piling into the riverbank. Electromagnetic measurements were performed using Witten Technologies’ prototype array of induction receivers (AIR) system. The AIR system is based on electromagnetic induction measurement techniques and operates on the same basic principles as traditional handheld radio-detection devices. An electric current is induced in a subsurface utility line. The induced current produces a magnetic field that is detected at the surface. The AIR system provides 48 simulta- neous magnetic field measurements over an 8 ft swath. Mag-

119netic field data are typically collected on a 1-ft × 1-ft grid spac- ing over the entire survey area. The position of the AIR sys- tem is tracked using an accurate positioning system such as a robotic laser tracking system that provides centimeter posi- tion accuracies. The data is processed using advanced electro- magnetic modeling techniques. The combination of the sensitive broadband three-component sensors, the volume and density of the data collected, and the advanced data pro- cessing and interpretation techniques used enabled detection of deep pipes in complicated environments. In the JEA project, the AIR system determined the utility line to be about 7-ft deep at the shallowest point on shore and about 35-ft deep at the deepest point on shore. Additionally, waterborne measurements were performed at various points on the river that detected the utility line crossing the river at a depth in excess of 50 ft. Case Study No. 19: Alaska Way Viaduct and Seawall Utility Mapping Project, Washington DOT To a large degree, this project incorporated many of the tech- niques, equipment, and concepts developed over the past half century for utility mapping. The utility mapping scope of work for the viaduct project was robust and included charac- terization data not normally obtained for transportation proj- ects. This extra characterization was necessary because of the tight corridor for utility relocations, cost and time estimating for utility owners, and continuity of utility service. It also pro- vided enough data for a preliminary 3-D model. This charac- terization included quality levels, ownership, size, inverts on all cables or conduits leaving all vaults, vault depth and out- side dimensions, depictions of every cable or conduit between vaults or its terminating point, utility depths at all valves, util- ity depths from records interpretations, pole or circuit riser numbers, and basement-wall termination points. Vault dia- gramming forms were included for each vault on the project. GPR, five different pipe and cable locators, magnetic tools, active and passive acoustics, terrain conductivity, and many differing coupling and insertion techniques were used to detect and trace utilities. A vast majority of utilities from records were mapped at quality level B, and many additional utilities not on record were found and mapped. The project environment pre- sented many challenges. These included right-of-way (ROW) scheduling and access issues, heavy, high-speed traffic on the southern portion, heavy pedestrian and vehicle traffic through the downtown portion, security issues related to the homeless or panhandlers, and an extremely congested and complex underground utility environment. Underground basements, corridors, and parking garages routinely extended beyond building walls and needed investigative access. Coordinationof sports events and other special events was required. Over 500 vaults were entered, roughly 100 of which needed dewater- ing. About 200 test holes for quality level A data were con- structed. Project hydraulic designers needed to know the elevations, size, shape, material, and type of footings for three large-diameter sewer lines. One of these sewers, in the middle of S. Royal Brougham, was a 112-in. diameter reinforced con- crete pipe (RCP), set in a concrete cradle on wood piers. The entire structure was 13-ft across and over 13-ft deep. The bot- tom of the cradle was below groundwater. The pipe was cracked, and sewage was evident in the excavation. Case Study No. 20: Prairie Parkway (SR-71), Kendall County, Illinois The Illinois Department of Transportation (IDOT) hired a SUE company to perform quality level B and quality level A mapping in a limited area of District 3. The scope of work was to designate various gas, petroleum, and crude oil pipelines ranging in size from 10-in. to 36-in. in diameter. The SUE consultant used a variety of pipe and cable locators with dif- ferent connection methods. GPR was found to be ineffective because of the conductive nature of the local soil conditions. Test holes were excavated at several points of conflict with the proposed interchange. After reviewing the results, IDOT elected to change the location of the interchange. Early use of the SUE deliverables in the design process permitted IDOT to adjust which properties were to be purchased. Case Study No. 21: Road Improvements, ILL 159, Collinsville, Illinois In IDOT District 8, a SUE consultant designated over 178,000 ft of underground utilities as well as overhead utilities, mobiliz- ing six field-designating teams and providing continuous input to the client to keep this high-profile project on schedule. Sewer mapping required manhole access and the insertion of composite core reels. This project was unique in that all qual- ity level B services were performed before background map- ping was developed. A total of 56 test holes were excavated at potential conflict zones for precise depth and elevation (qual- ity level A data). Case Study No. 22: New Mississippi River Bridge Crossing, Illinois In IDOT District 8, a SUE consultant mapped about 23,000 ft of underground utilities. This included a large unimproved landfill area with no available utility records. A variety of

120utility search and trace techniques were used to identify metallic and nonmetallic utilities. This project was excep- tional because of the necessary coordination with several rail- roads that crisscrossed the area. Case Study No. 23: IL Route 157, St. Clair County, Illinois In IDOT District 8, a SUE consultant performed designating, surveying, and utility mapping at quality level B of about 46,000 ft of utilities, as well as excavating a total of 44 test holes for precise depth and elevation. One test hole on a san- itary line was more than 15 ft deep. Case Study No. 24: I-35/I-670 Improvement, Jackson County, Missouri The Missouri Department of Transportation (MoDOT) hired a SUE consultant to perform quality level B mapping and discovered an extensive number of fiber-optic facilities that had a direct link into and out of an AT&T building in the northeastern portion of the project. Due to inadequate util- ity records and inadequate confidence in the utility’s owner- ship, it became imperative to gain access to the large quantity of fiber-optic splice chambers present within and outside project limits. After extensive research and discussions with the numerous fiber-optic utility owners, access to the splice chambers was granted, enabling successful designation of the fiber-optic facilities within the project’s limits. This required toroid clamps and composite core insertion coupling tech- niques, combined with low-frequency pipe and cable locators to distinguish individual cables. Case Study No. 25: Raleigh-Durham International Airport, North Ramp General Aviation Redevelopment, North Carolina A SUE company completed quality level B investigation of more than 71 acres of airport property, including public access roads and the general aviation area of Raleigh-Durham International Airport (RDU). During this work, 67,437 ft of underground utilities were designated using quality level B. A variety of pipe and cable locators, magnetic locating tools, and GPR were used. The breakdown by utility and owner systems is as follows: water (RDU): 6,926 ft; power (Progress Energy, RDU, FAA): 10,200 ft; communication (BellSouth, FAA): 29,108 ft; gas (PSNC Energy): 5,825 ft; FSS (RDU): 1,1960 ft; unknown utilities: 13,419 ft. The designation process included accessing and inspecting 15-plus utility vaults hous-ing facilities owned by BellSouth, Progress Energy, FAA, and RDU. This mapping was supplied in AutoCAD and incorpo- rated into the airport’s GIS. Case Study No. 26: Honolulu International Airport, Honolulu, Hawaii A SUE subcontractor was hired by M-K International, con- tractors for the terminal upgrade and other improvements at Honolulu International Airport. The scope of the work included collecting and depicting all utility information in the affected areas. This airport included a large military shared presence, and existing records were of very dubious quality. The SUE consultant evaluated the veracity and origin of the existing records, upgraded their quality through field surface geophysical imaging and, where necessary, through excava- tion. Over 250,000 ft of existing utilities of all types were sub- sequently depicted at quality level B. A wide variety of pipe and cable locators, coupling techniques, magnetic tools, and elastic wave techniques were used to detect and trace utilities. Confined space entry with vault dewatering was extensive. Case Study No. 27: Dulles International Airport and Reagan National Airport, Northern Virginia Parsons Management Consultants (PMC), a consortium of firms that operate as construction manager for Metropoli- tan Washington Airports Authority’s (MWAA) upgrades at Dulles International Airport and Reagan National Airport, hired a SUE contractor to provide utility mapping services on an on-call basis. One of the projects involved verifying and upgrading the airport’s existing GIS utility data for a design involving the parking deck at Reagan National Air- port. Between the airport-supplied utility GIS data (shown at quality level D) and the field investigation data (quality level B), there was a 30% rate of error, omission, or both. These discrepancy findings resulted in significant project savings to MWAA. In addition, this data served as an impor- tant catalyst for many recommendations found in the FAA’s ASA-500 Final Report Cable Cuts: Causes, Impacts, and Pre- ventive Measures. Case Study No. 28: Lambert Field, St. Louis, Missouri This was the nation’s first project using the FAA’s 2003 pol- icy on subsurface utility engineering as a design and damage prevention tool. Portions of the project were on the Air National Guard base. Pipe- and cable-locating equipment

121frequencies and power were tightly controlled and coordi- nated with the base munitions officer. Specific pipe and cable locators with acceptable frequencies, magnetic tools, insertion techniques, terrain conductivity, and elastic wave techniques were used, along with specific discrete area cou- pling methods. GPR was not used because of potential inter- ference with FAA communications. A security benefit was realized when an unsecured large-diameter sewer was dis- covered running from off base to under the munitions stor- age area. Case Study No. 29: Virginia DOT, Richmond The Virginia Department of Transportation (VDOT) used subsurface utility engineering in a major highway project in the City of Richmond, including designation and surveying of the route to determine “as-built” utility positions. In total, 156 test holes were excavated, and nearly half (75 sites) of the utilities verified via test holes were in conflict with the proposed utility facilities. As a result, design changes were made and 61 of the potential conflicts were eliminated. By making these changes, $731,425 worth of utility adjustments were avoided. The cost of digging the test holes was only $93,553, resulting in a savings of $637,872 and a benefit-to- cost ratio of 6.82:1. In the words of Mr. Richard Bennett, former state utilities engineer, “We feel like we eliminated over $700,000 worth of utility conflicts, and the cost . . . was less than $100,000. We can’t imagine going back and doing a project without having this information available to us.” Overall, VDOT credits SUE with helping to reduce the time needed to design highways from five years to four years, a 20% time reduction. Case Study No. 30: Route 29 Bypass, Warrenton, Virginia VDOT was interested in obtaining the elevation of a tele- phone duct run in Warrenton. The duct run made a turn between manholes that were about 600 ft apart. Snaking the ducts to obtain an adequate designating signal proved in- effective because of the facility’s extreme depth. Numerous test holes were excavated to get an alignment on the facility at the point where VDOT needed data. That facility was deep, and large debris in the backfill thwarted vacuum excavation. Finally, a track loader was used to remove the top 8 ft of cover. This method was still not enough to obtain the information. Working with VDOT, a large track excavator was used to cut the top 17 ft and a trench box was emplaced. Designating technology was then used to refine the horizontal location, and vacuum excavation within the trench box was used to expose the utility.Case Study No. 31: Virginia DOT, Crystal City During the planning of major highway upgrades in a highly congested area, the SUE study found major relocation prob- lems. In one case, an access ramp was designed to be placed directly over an underground shopping mall. This one re- location alone saved over $1 million. Utilities were difficult to designate because, in some cases, utility conduits were inte- grated with the underground structures. Trenchless technol- ogy methods were planned to emplace a storm drain over an existing electric duct that was a main power circuit for the Pentagon and Reagan National Airport. The SUE company recommended quality level A data on the duct, even though the profile depicted on the plans, through invert measure- ments in adjoining vaults, showed no conflicts. It was found that the electric duct, which was bowed upward between the vaults, was in direct conflict with the proposed microtunnel- ing, a finding that averted major utility damage. Case Study No. 32: Virginia DOT, Route 620, Fairfax County A utility coordination services effort revealed numerous con- flicts between the proposed road alignment, high-voltage trans- mission lines, and buried petroleum pipelines. The SUE study yielded a preliminary utility relocation cost estimate to quan- tify costs and to compare alternatives, such as redesign of the roadway alignment. As a result, the plans were sent back to design for realignment. The savings to VDOT were significant. Case Study No. 33: Virginia DOT, Covington On a subsurface utility engineering project in Covington, Virginia, a SUE study was able to locate and map a terra-cotta sewer dating from 1925. There were no access points, and records were sketchy. The investigation extended beyond records research to interviews with people who had helped build the system. Using a combination of sondes and ex- ploratory vacuum excavation, the SUE company accurately mapped the horizontal and vertical location of utility con- flicts with the proposed road construction. Case Study No. 34: North Carolina DOT, Capital Boulevard, Wake County The North Carolina DOT (NCDOT) requested 60 test holes based on previously furnished designating information. Many of the test-hole locations were in pavement along this

122heavily congested primary roadway. Traffic-control require- ments were significant and, whenever possible, several utili- ties were documented in a single test hole. This resulted in considerable cost savings. Evaluation of the information indi- cated that the location of a nondesignated sanitary line dif- fered from existing plan depictions, conflicting with proposed features. Other services included terrain conductivity and magnetic searches for anomalies, with subsequent air/vacuum excavation methods. This approach was successful in identi- fying the exact location and condition of a buried sanitary structure that was in conflict with a proposed retaining wall and temporary sheeting/pile operations. Had this main inter- ceptor sewer been damaged, there would have been severe environmental consequences. Services were provided within the project’s tight time schedule. Case Study No. 35: North Carolina DOT, I-40 Rest Area, Haywood County The study included designating and CCTV inspection ser- vices on water and sanitary facilities crossing I-40. Designating identified the location of the existing water line and enabled NCDOT personnel to confirm the existence of a useable casing pipe crossing I-40. CCTV inspection services revealed that the existing sanitary line under I-40 was structurally sound and identified several conditions contributing to flow problems. Case Study No. 36: North Carolina DOT, Lenoir, Caldwell County SUE was used early in the development of a project on the Southwest Loop Extension in Lenoir to identify utilities that needed to be relocated. About 58 test holes were selected at points of potential conflict. In addition, a geophysical inves- tigation was conducted in 11 sites to search for unrecorded underground storage tanks. Based on the SUE data, the loca- tions of 16 storm-drain boxes were changed to eliminate util- ity conflicts. The SUE contractor also detected underground storage tanks near the proposed right-of-way limits and con- structed test holes to determine the precise position of the previously unrecorded storage tank locations. Case Study No. 37: North Carolina DOT, Raleigh Beltline, Wake County Many of the facilities on this site were made out of thermo- plastic materials and, thus, required extensive record inter- pretation and correlation with field data. Additionally, some water and sanitary force mains were privately owned with noavailable records. The SUE consultant detected the presence of these facilities through sweeping procedures and by per- sonal interviews with local residents to identify the private- facility owners. Case Study No. 38: North Carolina DOT, NC 138, Currituck County SUE was used on a highway project in North Carolina to locate a PVC water line along 18 mi of NC 168 in Currituck County. Location of the line was critical to determine conflicts with proposed pavement-widening and shoulder-excavation work. Using vacuum excavation, 40 holes were dug at a cost of less than $10,000. From the resulting quality level A informa- tion, it was determined that about 21,280 ft of the water line could remain in place. The resulting saving to NCDOT was estimated at $500,000, a benefit-to-cost ratio of 50 to 1. Case Study No. 39: Pennsylvania DOT, Erie A SUE consultant was asked to designate and map active and abandoned steam lines near the waterfront area in Erie, Pennsylvania. The city was undergoing major redevelopment of the waterfront area and was gradually phasing out a Penn- sylvania Electric plant in the vicinity. In addition to provid- ing electricity, the plant also provided steam for heating. The records on the location of the steam pipes were extremely poor. In addition, the pipes were insulated in asbestos, and there was a concern that disturbing the pipes would create an environmental hazard. The SUE consultant mapped the entire system (live and abandoned). It was found that the asbestos was encased in concrete or double piping and posed minimal environmental hazard. So-Deep performed about 65,000 ft of designating services and excavated 40 test holes. Case Study No. 40: Pennsylvania DOT, Lackawanna Industrial Highway, Lackawanna County The SUE consultant performed designating and locating services on a fast-track basis for Lackawanna Industrial High- way. It coordinated with five different consultants to provide the Pennsylvania DOT (PennDOT) with accurate design information. These projects presented substantial technical difficulties. The terrain provided obstacles for crews because the utility ran cross-country through coal fields. Existing sur- vey control was sporadic throughout the project and very few surface structures existed. Consequently, considerable survey work was necessary to document utility information.

123Case Study No. 41: Delaware DOT, S. Madison Street Connector This project sought to provide access to the proposed devel- opment of the Christiana Riverfront. The site was a former industrial park dating to the early 1900s. While providing subsurface utility engineering services on this project, the SUE consultant found significant discrepancies between util- ities indicated on records and those that actually existed. About 15,500 ft of underground utilities were designated and 72 test holes excavated. Case Study No. 42: Maryland State Highway Administration, Columbia A highway project in Columbia, Maryland, involved the realignment and widening of the roadway from two to six lanes. Maryland State Highway Administration (MSHA) con- tracted a SUE study to support the relocation of water, sewer, gas, telephone, electric, and cable television (CATV) facilities along Route 29 in Columbia, Maryland. This project involved both arterial/collector road and interstate/expressway require- ment options for both overhead and underground utilities. MSHA engaged the SUE consultant in the relocation design for a gravity sanitary sewer that was in conflict with a pro- posed storm retention pond. The use of SUE enabled MSHA to redesign the hydraulics system to minimize conflicts with utilities. Instead of affecting about 5,000 ft each of gas, water, and sanitary utility, conflicts were reduced to about 400 ft of each. The cost for SUE was $56,000. Cost savings to MSHA and the utilities amounted to $1,340,000. The benefit-to-cost ratio equals 23.9 to 1. Case Study No. 43: Maryland SHA, Montgomery County MSHA hired a SUE consultant to perform an estimate of util- ity congestion and a dollar estimate for utility relocation on a project in Montgomery County on MD Route 355. The con- sultant designated about 80,000 ft of utilities, located 125 util- ities and points of conflict, and provided a determination of septic systems and wells and underground storage tanks that might affect right-of-way acquisition, highway design, and construction. Case Study No. 44: Maryland SHA, New Hampshire Avenue About 60 homes and businesses along 10 miles of this urban/ rural stretch had no records of their septic systems, wells, or underground storage tanks. Previous construction on a dif-ferent section of the road was delayed, property was pur- chased at a premium price, temporary housing and cleanup costs were incurred, and extra orders promulgated when the excavator discovered such buried structures within the con- struction zone. The SUE study included a review of septic sys- tem, well, and underground storage tank installation practices, as well as a review of surface geophysics and nondestructive testing techniques to identify the drainage fields, wells, and underground storage tanks. Case Study No. 45: Maryland SHA On another project in Maryland that involved widening an interstate highway from four to six lanes with full shoulders, retaining walls, and barriers, the use of SUE enabled MSHA to redesign the barriers and change the grading and ditches to minimize conflicts with gas, water, and telephone utilities. The cost for SUE was $5,000. Cost savings to MSHA and the utilities amounted to $300,000, and the relocation time was reduced by 46 months. Case Study No. 46: Ohio DOT, Chagrin Boulevard, Cleveland The Ohio DOT (ODOT) acquired designating and locating services to assist in the design of the widening of Chagrin Boulevard. The study revealed many discrepancies between the utility records and the actual utility positions. In one case, a sewer line that was recorded as being on the south side of Chagrin Boulevard was actually on the north side. In another case, a pipe that was recorded as carrying tele- phone lines was actually a gas line. An ODOT representa- tive stated to the Chagrin Herald Sun, “This should help us avoid any delays once the project begins. We are spending more money up-front, but saving time and money in the long run.” Case Study No. 47: Mapping Requirements for Permit Applications, Greenwood Village, Colorado, 2002 In 2002, the City of Greenwood Village, Colorado, insti- tuted new mapping requirements for its permit applications for companies seeking to install new lines within its bound- aries. Applicants are required to determine the location— both vertical and horizontal—of all existing utilities within the permit area and to provide the city with a map in a GIS format of their findings. This information is available to all underground-utility owners and contractors. The city man-

124dated two levels of permits. For projects less than 500 ft, the applicants are required to pothole every 100 ft on either side of the proposed new utility as well as at line crossing. For projects longer than 500 ft, the entire right-of-way must be mapped. Case Study No. 48: Florida DOT, District 4, West Palm Beach, 2003 In late fall 2003, the West Palm Beach Operations Center of District Four, Florida Department of Transportation (FDOT), decided to undertake a test of computer-aided radar tomog- raphy. Radar tomography (RT) is a technology that employs a radar array to penetrate soil to locate subsurface structures or other anomalies. As the array was set up, signal strength of 200 MHz was attained by arrays of 9 transmitting and 8 receiving antennae. Witten Technologies, Inc., was the ven- dor hired to conduct the tests. The objective of the study was to determine if RT technology was capable of giving better information regarding subsoil conflicts for buried utilities and foreign anomalies, such as buried rock or concrete, building pads, and walls, compared with traditional SUE methods. The technology was tested on two FDOT projects in the West Palm Beach area. It was found in the Olive Avenue project that Witten Technologies was able to locate about 50% of the existing utilities drawn and identified by the designers. Recommendations from the FDOT report included: (a) radar data interpreters should be more cog- nizant of the specific needs and procedures of the FDOT; and (b) better communication was needed between the service provider and the DOT as to expectations and abili- ties. While this particular evaluation of computer-aided radar tomography technology was not as successful as had been hoped, overall, Florida has a good experience with SUE technology. For example, Florida DOT analyzed the use of SUE on two major projects in Tallahassee and Miami and concluded that it saved $3 in contractor construction delay claims for every $1 spent for SUE. Case Study No. 49: Columbus Southern Power Company, Columbus, Ohio On a utility project in Columbus, Ohio, the Columbus Southern Power Company designed and installed almost 1.24 miles of underground 138 kV electric line through the downtown area at lower cost, reduced risk, and ahead of schedule by including SUE in its design. The increased qual- ity of the utility information presented at the pre-bid meet- ing increased the bidder’s confidence in the construction plans, resulting in a bid that was $400,000 less than antici-pated. The cost of SUE was less than $100,000, with a benefit- to-cost ratio of 4.00 to 1. Additionally, there were no change orders as a result of utilities not correctly depicted on the plans, no utility relocations, no utility damages on the proj- ect, and no contractor claims. Case Study No. 50: SR 4013-002, Pennsylvania DOT Engineering District 9-0, Hollidaysburg The Seventh Street Bridge replacement, City of Altoona, proj- ect took place in an urban area and involved replacing an existing bridge, widening traffic lanes, and constructing new bridge approaches. A large underground phone system had been relocated near the project site two years prior to the project. The project length was about 0.5 mi. Available infor- mation revealed a 16-in. gas line, a 12-in. water and sewer line, three underground fiber-optic lines in different conduit runs, and a buried telephone and vault, as well as some unknown lines, in the project area. However, the exact loca- tion and direction of the existing lines were unknown. For quality level B SUE investigation, electromagnetic equipment was used in coordination with the utilities to introduce a sonde into the pipelines. For quality level A, the vacuum exca- vation method was conducted at 44 different locations. As a result of the SUE investigation, the roadway drainage facili- ties were successfully designed to save time and relocation expenses, and the potential impact of bridge pier construc- tion on the existing lines was avoided. The total project cost was $11.6 million, including design and construction cost, of which design cost was $2.0 million. SUE cost was $50,000 (designating $23,000; locating $27,000). The cost saving from using SUE was $1,515,000 (utility relocation $500,000; design and construction $1.0 million; information gathering and verification $15,000). Thus, the benefit-to-cost ratio was 30.3:1. Case Study No. 51: SR 0022-024, Pennsylvania DOT Engineering District 9-0, Hollidaysburg The Third Ave. Bridge project was a replacement of an entire existing bridge located in an urban area with high traffic vol- ume. Three water authorities crossed at this bridge. Two lines were 12 in. in diameter. There was also a telephone conduit system and vault near the bridge, with 10 conduits attached to the existing bridge. Homes and businesses were adjacent to the bridge and allowed little or no room to relocate the facil- ities. The project length was about 0.25 mile. This was a time- sensitive project. The initial utility information was incorrect.

125The SUE firm found that the utility-marked plans were wrong. The quality level B SUE investigation was conducted using electromagnetic equipment along with close coordina- tion with the utilities. For quality level A, the vacuum excava- tion method was performed at nine different locations. As a result of the SUE investigation, it was possible to design shoring around existing telephone conduits, to design the bridge to accommodate the telephone facilities, and to pos- itively identify the gas line and determine that it was not affected. The total project cost was $2.6 million, including design and construction cost, of which design cost was $600,000. SUE cost was $50,000. The cost saving from using SUE was $265,000 (utility relocation $150,000; design and construction $100,000; information gathering and verification $15,000). Thus, the benefit-to-cost ratio was 5.3:1. Case Study No. 52: SR 0036-25M, Pennsylvania DOT Engineering District 9-0, Hollidaysburg The 18th St. Culvert, Blair County, project was to add drainage to an existing road and also to lower the roadways as much as possible to provide additional overhead clearance for trucks to go freely under a railway overpass. The available information revealed that there was a complex existing util- ity network at the project site. This included a 12-in. diame- ter gas line, a 16-in. diameter water pipeline, a large buried telephone system, an underground electric system, and an abandoned 36-in. sewer culvert along with a 72-in. sewer pipe, all within a 22-ft-wide roadway. For SUE quality level B inves- tigation, electromagnetic equipment was used in close coor- dination with the utilities. For quality level A investigation, the vacuum excavation method was conducted at 15 differ- ent locations. Results of the SUE investigation indicated that many of the facilities were abandoned and that the proposed gas line relocation would not work. Also, SUE provided proper locations for the inlet and drainage facility. Time was the most valuable saving for this project. An additional ben- efit was that, based on the SUE results, the water authority was convinced to replace a 100-year old 24-in. diameter water line while the road was open. The total project cost was $1.6 million, including design and construction cost, of which design cost was $200,000. The SUE cost was $44,804 (designating $15,000; locating $29,804). The cost saving from using SUE was $1,515,000 (utility relocation $275,000; project delay cost by utility relo- cation $50,000; redesign $75,000; design $5,000; construction $1,095,000; information gathering and verification $15,000). Thus, the benefit-to-cost ratio was 33.81:1.Case Study No. 53: SR 2014-04M, Pennsylvania DOT Engineering District 9-0, Hollidaysburg The Cresson Culvert, Cambria County, project was to rebuild a roadway under a railway overpass. The work involved complete reconstruction of a portion of the roadway and installation of drainage facilities. Preliminary information revealed a gas line parallel to the roadway, plus an underground telephone line and water pipeline within the project site. However, the exact location and depth of the pipelines were unknown. Quality level B investigation used electromagnetic equipment and close coordination with utilities. For quality level A, vacuum excava- tion was performed at 15 different locations. Based on the results of the SUE investigation, the drainage facilities were designed to avoid utilities at various locations. The results of SUE also allowed the gas company to better plan for relocation. The total project cost was $2.4 million, including design and construction cost, of which design cost was $710,000. The SUE cost was $34,243 (designating $11,000; locating $23,243). The cost saving from using SUE was $165,050 (utility relocation $5,050; design and construction $150,000; information gathering and verification $10,000). Thus, the benefit-to-cost ratio was 4.82:1 Case Study No. 54: Pennsylvania DOT Engineering District 3-0, Montoursville The Towanda River Road, Bradford County, project was to construct a roadway to bypass the center of Towanda, thereby relieving traffic congestion. Preliminary information revealed many undocumented underground obstacles at the project site, including sanitary sewer, water, gas, telephone, TV, and electric lines for which there was no exact location informa- tion. Throughout the project site, there were also abandoned water and sewer lines without exact locations. Quality level B information was collected using pipe and cable locators. For quality level A information, vacuum excavation was per- formed at about 150 locations. Based on the results of the SUE investigation, a decision was made to place the drainage facilities at a location at the site that did not interfere with the existing underground utilities. The total project cost was $13.0 million, including design and construction cost, of which design cost was $1.0 million. The SUE cost was $141,000 (designating $66,000; locating $75,000). The cost saving from using SUE was $4,210,000 (utility reloca- tion $1.5 million; project delay by utility relocation $100,000; change orders and claims $75,000; restoration $35,000; project delay cost by the emergency $1.5 million; design $1.0 million). Thus, the benefit-to-cost ratio was 29.86:1.

126Case Study No. 55: SR 0015-077, Pennsylvania DOT Engineering District 3-0, Montoursville The Market St. River, Williamsport, project involved replac- ing a bridge into the city of Williamsport, installing traffic cir- cles, and reconstructing state route SR 15. The main purpose of the project was to relieve traffic congestion and to replace an old bridge. The project site had a very complex network of underground utilities that included sanitary sewer, water, gas, telephone, TV cable, and electric lines in unknown locations. Quality level B information was gathered using existing maps, surface features, and pipe and cable locators. About 110 vac- uum excavation tests were performed to determine quality level A information. The results of the SUE investigation resulted in locations for drainage facilities that had little inter- ference with the existing underground utilities. Also, the utility companies were given the accurate location of their under- ground facilities in this area. The total project cost was $63.0 million, including design and construction cost, of which design cost was $10.0 million. The SUE cost was $141,000 (designating $46,000; locating $95,000). The cost saving from using SUE was $4.5 million (utility relocation $3.0 million; redesign $500,000; design $1.0 million). Thus, the benefit-to-cost ratio was 31.91:1. Case Study No. 56: SR 0054-014, Pennsylvania DOT Engineering District 3-0, Montoursville The Danville River Bridge, Montour County, project was to replace an inefficient bridge, to improve traffic conditions, and to provide a railroad crossing in the Borough of Danville. At the project site, the sanitary sewer, water, gas, telephone, TV cable, and electric line locations were unknown. Very few maps of the existing pipelines were available. Quality level B information was determined using pipe and cable locators. About 25 vacuum excavation holes were performed to deter- mine quality level A information. Based on the results of the SUE investigation, a decision was made to place the drainage facilities at locations that were least affected by existing under- ground utilities. Also, the utility companies were provided accurate locations of their underground facilities. The total project cost was $9.0 million, including design and construction cost, of which design cost was $1.0 million. The SUE cost was $101,000 (designating $21,000; locating $80,000). The cost saving from using SUE was $2,650,000 (utility reloca- tion $1.0 million; design $1.5 million; construction $150,000). Thus, the benefit-to-cost ratio was 26.23:1.Case Study No. 57: SR 0061-079, Pennsylvania DOT Engineering District 3-0, Montoursville The Cameron Bridge, Shamokin, project was to replace a bridge and to relieve traffic congestion in the city of Shamokin. At the project site, there existed a very complex, undocu- mented underground network of pipelines, including sani- tary sewer, water, gas, telephone, TV cable, and electric lines. Also, there were over five water lines that needed to be tem- porarily, and then permanently, relocated. Quality level B information was determined using pipe and cable locators. For quality level A, about 30 vacuum excavation holes were used. The results of the SUE investigation provided locations for drainage facilities that were least affected by the existing underground utilities at the project site and that are now also documented. The total project cost was $9.0 million, including design and construction cost, of which design cost was $1.0 million. The SUE cost was $66,000 (designating $20,000; locating $46,000). The cost saving from using SUE was $1,500,000 (utility relocation $250,000; redesign $1.0 million; restora- tion $50,000; construction $200,000). Thus, the benefit-to- cost ratio was 22.72:1. Case Study No. 58: SR 0049-50M, Pennsylvania DOT Engineering District 3-0, Montoursville The Reconstruct Main St., Elkland, project involved recon- struction of SR-49 and replacement of sanitary and storm sewers, sidewalks, and curbs. Preliminary information revealed sanitary sewer, water, and gas lines at the project site but without specific positions. Quality level B information was determined using pipe and cable locators. Quality level A information was determined by conducting vacuum exca- vation at about 75 different locations throughout the proj- ect site. From the results of the SUE investigation, the roadway drainage facilities were located at places posing the least inter- ference to the existing underground utilities. The results of the SUE investigation also provided the utility companies with an accurate location for their underground pipelines. The total project cost was $5.2 million, including design and construction cost, of which design cost was $700,000. The SUE cost was $56,000 (designating $26,000; locating $30,000). The cost saving from using SUE was $1.9 million (utility relo- cation $1.8 million; construction $100,000). Thus, the benefit- to-cost ratio was 33.92:1.

127Case Study No. 59: SR 0865-002, Pennsylvania DOT Engineering District 9-0, Hollidaysburg The Bellwood Road and Bridge, Blair County, project involved relocation of a roadway and reconstruction of a bridge in the rural area of Bellwood. The SUE process was used on the roadway portion to design drainage facilities. In the early project stage, there was some information concerning a gas line on one side of the existing road and a water line on the other side at the project site. Quality level B information was determined through basic electromagnetic equipment such as pipe and cable locators and metal detectors. For SUE qual-ity level A, vacuum excavation was used at 15 different loca- tions. Based on the results of the SUE investigation, the deci- sion was made to place drainage facilities on the side of the road where the water line was located. On that side of the road, there was less conflict and more room for relocation; additionally, the work could be done by the department of transportation contractor. The total project cost was $3.1 million, including design and construction costs, of which the design cost was $330,000. The SUE cost was $20,000 (designating $10,000; locating $10,000). The cost saving from using SUE was $65,000 (utility relocation $5,000; design and construction $50,000; informa- tion gathering and verification $10,000). Thus, the benefit-to- cost ratio was 3.25:1.