One of the investigated sections of the garage. Infrasense used a walking survey supported by a vehicle to power the walking-based GPR setup..
Boston, MA (PRWEB) August 21, 2014
Infrasense, Inc., one of the leading subsurface detection firms in the nation, recently completed ground penetrating radar (GPR) testing of select areas of a five-level parking structure in Rochester, New York. Corrosion of the post-tensioned steel within the concrete slabs, especially near expansion joints, was a primary focus of the subsurface investigation. Using a walking-based survey with a 1.6 GHz GPR antenna to provide higher resolution data, the designated survey areas were scanned in less than two days, with 100% coverage achieved in all accessible areas and minimal disruption to garage parking services. The results of this investigation will be used for future rehabilitation planning. In 2009, Infrasense performed similar nondestructive evaluation services for a different parking garage in Rochester.
Nondestructive evaluation (NDE) uses a number of techniques to determine material or structural properties without causing damage to the structure being evaluated. Because these techniques can be applied to a wide range of structures without any adverse effects, they have become a powerful decision-making tool in the assessment of as-built conditions, and in the inspection and maintenance of infrastructure. The type of structure and the condition to be detected dictates what NDE techniques will be most useful in a condition assessment.
Ground penetrating radar (GPR) is an NDE technique that operates by transmitting short pulses of electromagnetic energy into the concrete, using a boxed antenna attached to a survey vehicle or rolled along the slab. These pulses are reflected back to the antenna providing a record of the properties and thicknesses of the layers within the slab. GPR can detect the depth and spacing of reinforcing steel, and the thickness of concrete slabs. It is able to detect subsurface deterioration of a slab through changes in the radar signal through the concrete. These results make GPR a useful tool in planning preventative maintenance and avoiding severe and costly structural issues down the road.
In addition to GPR surveys, impact echo testing is an NDE technique used to determine slab thickness, to identify areas of delamination and substandard concrete. An elastic wave is generated by an impact source, and the clarity and frequency of the wave reflection indicates the slab thickness and condition. Impact echo tests may be used in conjunction with ground-penetrating radar to detect areas of the slab that have already begun to deteriorate and measure the extent of the deterioration. In the past, Infrasense has used impact echo testing on similar parking garage surveys.
Nondestructive evaluation techniques allow us rapidly and economically assess the condition of parking structures. This information then enables owners to better allocate their maintenance funds to ensure the areas of significant damage are repaired, and eliminates the costs and risks of performing unnecessary maintenance.
About Infrasense, Inc.
Since 1987, Infrasense, Inc. has applied state-of-the-art technologies to address the most difficult challenges in subsurface scanning. Infrasense’s engineers are able to nondestructively extract critical information from a diverse range of structures. In addition to providing ongoing subsurface evaluation services to clients across the country, the firm has also conducted numerous research programs to advance the field of subsurface detection and non-destructive evaluation. To learn more about Infrasense and the services we provide, visit our website: http://www.infrasense.com
