An average construction project in the United States have savings of $4.62 for every dollar spent on SUE (Subsurface utility engineering).
Why does SUE save 4.6x on every dollar spent?
The concept of SUE is gaining popularity worldwide as a framework to mitigate costs associated with project redesign, construction delays, and to avoid risk and liability that can result from damaged and injuries with underground utilities.
What is Subsurface Utility Engineering?
Subsurface utility engineering (SUE) refers to a branch of engineering that involves managing certain risks associated with utility mapping at appropriate quality levels, utility coordination, utility relocation design and coordination, utility condition assessment, communication of utility data to concerned parties, utility relocation cost estimates, implementation of utility accommodation policies, and utility design.
What services are used to obtain SUI?
(SUI, Subsurface Utility Information)
The SUE process begins with a work plan that outlines the scope of work, project schedule, levels of service vs. risk allocation and desired delivery method. The main service used are Utility Locating, Concrete Scanning, Non Destructive Digging, Geo-technical Investigations, Surveying, Engineering and Project Management. Below are an outline of those services.
-Utility Locating (Identify, Plan & Locate)
Gather and Interpret QLD/QLC/QLB/QLA, Initial Utility Identification, Planning and Locating (Electromagnetic Locating/Ground Penetrating Radar)
-Non Destructive Digging Services (NDD)
Hydrovac excavation is a form of soft-dig excavation technology that allows one to move or remove soil. This technology uses high-pressure water – either hot or cold – to move the soil or debris while simultaneously vacuuming it out. This non-destructive method of excavation allows for a more accurate way to move the soil without using any mechanical means, reducing the possibility of damaging underground infrastructure. Hydrovac excavation may also be called hydro vacuum excavation.
Daylighting QLD/QLC/QLD Information to QLA, Non-destructive surface geophysical methods are then leveraged to determine the presence of subsurface utilities and to mark their horizontal position on the ground surface. Vacuum excavation techniques are employed to expose the precise horizontal and vertical position of the assets. (NDD, Hydro Vac, Concrete Coring/Cutting)
– Geotechnical Engineering Investigation
Geotechnical investigations are performed by geotechnical engineers or engineering geologists to obtain information on the physical properties of soil earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions.
– Surveying (Land, Building, Civil, Utility)
QLA Drafting, Surveyors then pickup the precise horizontal and vertical position of the assets and other information for the desired scope (dGPS/GNSS, Total Station, 3D Scanners)
Surveyors work with elements of geometry, trigonometry, regression analysis, physics, engineering, metrology, programming languages, and the law. They use equipment, such as total stations, robotic total stations, theodolites, GNSS receivers, retroreflectors, 3D scanners, LiDAR sensors, radios, inclinometer, handheld tablets, optical and digital levels, subsurface locators, drones, GIS, and surveying software.
-Computer Aided Design and Drafting (CADD)
AutoCADD The information is then typically presented in CAD format or a GIS-compatible map. (Software Including AutoCAD, 12D)
– SUI Engineers (Utility Project Managers)
A conflict matrix is also created to evaluate and compare collected utility information with project plans, identify conflicts and propose solutions. (Project Management software/BIM, acquired knowledge, systems and networks)
The following image is an example of a CADD deliverable, City of Toronto Utility Maps from SUI engineers. These maps are accessed by CADD software.
The City maintains all underground and above ground utility maps.
Does SUE Reduce Risk and Costs?
Few would argue that when implemented systematically by experienced technical experts, SUE provides an extremely effective framework to mitigate risk and cut costs.
A study conducted by Purdue University for the American Federal Highway Administration (FHWA) showed that out of 71 projects studied across the U.S., an average project savings of $4.62 was achieved for every dollar spent on SUE. In total, the projects showed a combined savings of more than $1 billion.
Moreover, the research demonstrated that obtaining Quality Level B or A on these projects added less than 0.5 % to the total construction costs and represented a savings in construction costs of almost 2%.”
However, despite growing awareness of SUE, there is little doubt there is still a long way to go. The 2012 DIRT Report that revealed more than 200,000 occurrences of damaged utilities across Canada and the United States, also uncovered that 60,000 of these projects had not involved a locate prior to excavation. With greater awareness, more than a quarter of these events could have been avoided within the year.