We provide the following services to our clients:
GPR uses high-frequency (usually polarized) radio waves, usually in the range 10 MHz to 1 GHz. A GPR transmitter pushes electromagnetic energy into the ground. When the energy encounters a buried object or a boundary between materials having different dielectric constants, it may be reflected or refracted or scattered back to the surface. A receiving antenna can then record the variations in the return signal. The principles involved are similar to seismology, except that electromagnetic energy is used instead of acoustic energy, and energy may be reflected at boundaries where subsurface electrical properties change rather than subsurface mechanical properties as is the case with seismic energy.
The electrical conductivity of the ground, the transmitted center frequency, and the radiated power all may limit the effective depth range of GPR investigation. Increases in electrical conductivity attenuate the introduced electromagnetic wave, and thus the penetration depth decreases.
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HGS offers locating services in the following industries:
- Cable TV
This technology is able to provide a real-time view of objects inside concrete in both 2D and 3D using a built-in screen.
The traditional method of locating things like rebar or tendons is to drill test-holes in selected areas. This is potentially dangerous, as you can easily hit a tendon and damage it.
This new technology allows for the location of hidden tendons within a few millimeters. Using a GPS Total Station, a record of the locations can also be provided by using control points in the floor, setting out positions on ceilings and of corresponding slabs.
Besides being non-invasive and non-destructive, radar scanning is also quick and accurate. This technology allows tendon positions to be located to within 20 mm.
Our scanner visualizes the data in real time, which makes it extremely user-friendly. Some of our customers estimate that they have achieved something in the order of a 30 to 50 per cent saving on our fees compared with other methods of locating. They have said that using conventional methods would have taken considerably longer and the results would not have been as clear or concise.
Utility LocatingUtility Locating is the process of identifying underground public utility mains. Because of the many different types of underground lines, different detection and location methods must be used. For metal pipes and cables, we use electromagnetic equipment. For other types of pipe, such as plastic or concrete, we use radiolocation or ground-penetrating radar. You can depend on us as your utility locators.
Utilities MappingUtilities Mapping is important because current maps are often wrong – if they exist at all. Sometimes utility pipes or cables are relocated during repairs or renovations, but maps are not updated. Sometimes maps represent proposed plans that don’t show as-built locations. Sometimes, old maps are simply lost or have disintegrated.
PotholingPotholing is the practice of digging a test hole to expose underground utilities to ascertain the horizontal and vertical location of the facility. The horizontal and vertical position of the exposed facility must be tied to a survey benchmark or permanent above grade feature.
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KeyholingKeyholing is pipeline maintenance using small hole techniques, where work is done from above ground through a small opening called a keyhole. This can easily triple productivity compared with conventional open pit repair methods, and is far safer as well.
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Air ExcavationAir Excavation turns a backbreaking, messy, and dangerous job into a fast, simple, and safe process. Utility professionals rely on air-vacuum excavation for locating underground utilities, and compared to systems that use water, air offers higher performance in most soils, greater efficiency, lower cost, and is less invasive than water.
For more information on the savings available from Subsurface Mapping, please refer to the paper: “Evaluation of Subsurface Utility Engineering for Highway Projects: Benefit Cost Analysis.” This study presents a benefit-cost analysis on 22 SUE and 8 non-SUE projects. Eleven (11) main benefit factors and 2 cost factors are identified and estimated for analysis. The results reveal that $11.39 can be saved for every $1 spent on SUE. A ratio of 1.65% is determined as the ratio of SUE cost to total project cost. This means that SUE can provide accurate utility information with reasonable cost. Click here to read more about SUE…
In general it is recommended that sand be changed about every 7 years or when the water quality has degraded to the point where visibility no longer meets Health Department standards. Sand wears out because of backwashing during which process the jagged edges are worn away by the tumbling action. Excessive backwashing speeds this process.
Another reason for changing sand has to do with the chemicals that are added to the swimming pool or body of water to maintain either sanitation (in swimming pools) or water balance. Operators often sanitize using calcium hypochlorite and adjust Calcium Hardness in the water balance using Calcium Chloride. Calcium, being the least soluble mineral can drop out of solution and coat the sand bed prohibiting the water from flowing through the sand, thus forcing the water through the space between the tank and the sand, a process called channeling. When either of these conditions exist, the sand needs to be changed.
Finally, if an operator sees sand at the point where the filtered water returns to the body of water, this is usually indicative of a malfunction in the laterals of the filter, necessitating the removal of the sand for investigation/repair.
Hawaii Geophysical Services is proud to include Cloacina among our family of solutions for Hawaii’s water needs projects. Cloacina selects the very best and most durable components for conveying and treating wastewater and then packages them in a superior stainless steel structure designed to outlast competitors’ coated steel plants by decades. Rust, corrosion and failed coatings are ancient history with Cloacina’s stainless steel package treatment facilities and their unparalleled warranty. Long after competitor’s coated steel package plants have been recoated and removed from service, their stainless steel plants will still be standing – monuments to Cloacina’s superior design, material selection and construction. Contact us to learn more about this solution for your water treatment needs.