Infrastructure: Subsurface Utility Engineering
Subsurface Utilities Engineering (SUE) or subsurface mapping is an engineering process for accurately identifying the quality of subsurface utility information needed for highway plans, and for acquiring and managing that level of information during the development of a highway project.
Maverick Engineering, Inc. performs both the designating and locating phases of subsurface utility engineering.
Designating means to indicate the presence and approximate horizontal location of underground utilities utilizing the application and interpretation of surface geophysical techniques, which include, but are not limited to, electromagnetic, magnetic, and elastic wave methods.
Locating means to characterize a utilities' spacial position, composition, condition, size, and other data that may be reasonably obtainable about the utility and its surrounding environment through its exposure by non-destructive excavation techniques, such as air/vacuum extraction.
MEI's licensed professional engineers and land surveyors are able to authenticate (seal) appropriate SUE deliverables in accordance with Texas professional requirements.
The subsurface utility data is transmitted in a format compatible with our client.s computer-aided drafting and design (CADD) system.
Quality Levels
Highway plans typically contain disclaimers as to the quality of utility information. The use of quality levels in the SUE process allows designers to certify on the plans that a certain level of accuracy and comprehensiveness has been provided. There are four quality levels:
- Quality Level D: information comes solely from existing utility records. It may provide an overall "feel" for the congestion of utilities, but it is often highly limited in terms of comprehensiveness and accuracy. Its usefulness should be confined to project planning and route selection activities.
- Quality Level C: involves surveying visible above-ground utility facilities, such as manholes, valve boxes, posts, etc., and correlating this information with existing utility records. When using this information, it is not unusual to find that many underground utilities have been either omitted or erroneously plotted. Its usefulness, therefore, should be confined to rural projects where utilities are not prevalent, or are not too expensive to repair or relocate.
- Quality Level B: involves the use of surface geophysical techniques to determine the existence and horizontal position of underground utilities. This activity is called "designating". Two-dimensional mapping information is obtained. This information is usually sufficient to accomplish preliminary engineering goals. Decisions can be made on where to place storm drainage systems, footers, foundations, and other design features in order to avoid conflicts with existing utilities. Slight adjustments in the design can produce substantial cost savings by eliminating utility relocations.
- Quality Level A: involves the use of nondestructive digging equipment at critical points to determine the precise horizontal and vertical position of underground utilities, as well as the type, size, condition, material, and other characteristics. This activity is called "locating." It is the highest level presently available. When surveyed and mapped, precise plan and profile information are available for use in making final design decisions. By knowing exactly where a utility is positioned in three dimensions, the designer can often make small adjustments in elevations or horizontal locations and avoid the need to relocate utilities. Additional information such as utility material, condition, size, soil contamination, and paving thickness also assists the designer and utility owner in their decisions.
Technologies: These technologies can be used to uncover pipelines, gas lines, phone lines, fiber optics, water or sewer - and other utilities up to 30 feet underground.
Hydro Excavation: Hydro Excavation is the science of digging with water. This is a safe and efficient form of excavation using a powerful vacuum and high pressure water. Precise holes, trenches and tunnels can be cut to the required size and proportion. Because water is used, the risk of damage to underground utilities is reduced and thus provides a safer means of excavation than with heavy equipment.
Ground Penetrating Radar (GPR):
Ground-penetrating radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. This non-destructive method uses electromagnetic radiation in the microwave band (UHF/VHF frequencies) of the radio spectrum, and detects the reflected signals from subsurface structures. GPR can be used in a variety of media, including rock, soil, ice, fresh water, pavements and structures. It can detect objects, changes in material, and voids and cracks.