Infrasense Inc.

Arlington, MA, United States

Infrasense Inc.

Arlington, MA, United States
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News Article | May 24, 2017
Site: www.prweb.com

Infrasense Senior Principal Dr. Kenneth Maser was recently selected, along with co-authors Nicole Martino, Ralf Birken, and Ming Wang, to receive the 2017 American Society of Nondestructive Testing (ASNT) Outstanding Paper award for their article titled “Quantifying Bridge Deck Corrosion Using Ground Penetrating Radar”, published in Research in Nondestructive Evaluation, May 2016. The authors will be recognized at the Annual Awards Banquet at the 2017 ASNT Annual Conference in Nashville, Tennessee, this autumn. The article concentrated on the development of a method to relate the results of Ground Penetrating Radar (GPR) analyses to the level of active corrosion in a particular bridge deck. The article also presents a step-by-step procedure for the development of an amplitude threshold for future bridge deck assessments using only GPR. The research that formed the basis of this article was carried out as part of the 5-year NIST-funded VOTERS project, led by Northeastern University. The project aimed to develop a cost-effective method to detect surface and subsurface roadway defects, enabling continuous network-wide health monitoring of roads and bridge decks without the need for expensive and hazardous work zones and road closures. The ideas behind the article were initially developed after lab testing of deteriorated bridge deck segments that were recovered intact after demolition. The availability of the “real” bridge deck conditions in the lab led to insights that motivated further research, and ultimately, the findings presented in the article. The American Society for Nondestructive Testing (ASNT) is comprised of over 16,000 members, making it the world’s largest technical society for nondestructive testing (NDT) professionals. It provides a wealth of services to the NDT community, including educational materials and certifications for NDT personnel. ASNT promotes NDT as a discipline by organizing and sponsoring conferences and meetings, and facilitating research. ASNT produces a number of publications, including Research in Nondestructive Evaluation, a quarterly journal that presents research from all areas of nondestructive testing. The journal publishes experimental and theoretical investigations in both the scientific and engineering applications of nondestructive evaluation. Research in acoustic, thermal, electrical, magnetic, and optical testing techniques are among the relevant topics published in the journal, with applications ranging from long-term health monitoring of structures, to the characterization of material properties. 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.


Martino N.,Northeastern University | Martino N.,Roger Williams University | Maser K.,Infrasense Inc. | Birken R.,Northeastern University | Wang M.,Northeastern University
Journal of Environmental and Engineering Geophysics | Year: 2014

The most expensive part to maintain throughout the lifespan of a reinforced concrete bridge is the deck, largely because rehabilitation occurs after degradation is visible on a surface. However, the mechanisms that are the cause of deterioration, such as reinforcing bar corrosion, are initiated long before damage is detected via visual inspection. If rebar corrosion can be detected in its early stages, before severe deterioration has resulted, maintenance costs can be significantly reduced and the life cycle extended. Recent studies have shown that ground penetrating radar (GPR) rebar reflection amplitude attenuation correlates with active corrosion in reinforced concrete bridge decks. A significant advantage of GPR over other non-destructive evaluation (NDE) methods is its ability to be operated at highway speeds so that traffic is not disrupted. However, a well-defined GPR amplitude threshold allowing the operator to distinguish non-corroded from corroded areas of the deck has yet to be established. Because reinforcing steel corrosion is the most predominant cause of bridge deck deterioration, this research seeks to quantify the thresholds relating GPR signal amplitudes and rebar corrosion. One bridge deck removed from service, seventeen artificially corroded slabs, and one in-service bridge deck were analyzed using GPR and half-cell potential (HCP), which measures the amount of active corrosion and is currently considered the standard NDE method. A significant correlation between these two methods was found for each case. To systematically determine a threshold for the GPR so that deteriorated areas of the deck can be identified, receiver operating characteristic (ROC) curves were utilized. With an accuracy of over 87% for each scenario, this method clearly demonstrates the use of GPR for distinguishing corrosion in bridge decks.


Martino N.,Northeastern University | Maser K.,Infrasense Inc. | Birken R.,Northeastern University | Wang M.,Northeastern University
26th Symposium on the Application of Geophysics to Engineering and Environmental Problems 2013, SAGEEP 2013 | Year: 2013

Throughout the lifespan of a reinforced concrete bridge, the most expensive part to maintain is the deck largely because rehabilitation occurs after degradation is visible on a surface. However, the mechanisms that are the cause of deterioration, such as reinforcing bar corrosion, are initiated long before damage is detected via visual inspection. If rebar corrosion can be detected in its early stages, before significant deterioration has resulted, maintenance costs can be significantly reduced and the life cycle extended. Recent studies have shown that ground penetrating radar (GPR) rebar reflection amplitude attenuation correlates with active corrosion in reinforced concrete bridge decks. A significant advantage of GPR over other non-destructive evaluation (NDE) methods is its ability to be operated at highway speeds so that traffic is not disrupted. However, a well-defined GPR amplitude threshold allowing the operator to distinguish non-corroded from corroded areas of the deck has yet to be established. Since reinforcing steel corrosion is the most predominant cause of bridge deck deterioration, this research seeks to quantify the thresholds relating GPR signal amplitudes and rebar corrosion. One bridge deck removed from service, seventeen artificially corroded slabs, and one in-service bridge deck have been analyzed using GPR and half-cell potential (HCP), which measures the amount of active corrosion and is currently considered the standard non-destructive evaluation method. A significant correlation between these methods was found for each case. In order to systematically determine a threshold for the GPR so that deteriorated areas of the deck can be identified, receiver operating characteristic (ROC) curves were utilized. With an accuracy of over 87% for each scenario, this method clearly exhibits the use of GPR for distinguishing corrosion in bridge decks.


Martino N.,Northeastern University | Birken R.,Northeastern University | Maser K.,Infrasense Inc. | Wang M.,Northeastern University
Structural Health Monitoring 2013: A Roadmap to Intelligent Structures - Proceedings of the 9th International Workshop on Structural Health Monitoring, IWSHM 2013 | Year: 2013

Throughout the life cycle of a bridge deck the most expensive part to maintain is the deck. The deck is replaced at least once and rehabilitated many times. However, the deck is the most important part of the bridge because it carries the traffic yet it is also exposed to harsh elements like deicing salts during the winter months. These deicing salts penetrate through the concrete and cause the reinforcing steel to corrode. The results of corrosion are cracks, delaminations and spalls. Current inspection methods, like visual inspection and chain drag, used to determine the deterioration condition of reinforced concrete bridge decks do not provide enough quantitative information about the deck. Nondestructive evaluation techniques like ground penetrating radar (GPR) have the ability to accurately and efficiently assess the internal composition of the deck by rapidly scanning over the surface at highway speeds. Previous research has shown that the electromagnetic signals emitted from GPR antennas are attenuated, or their amplitude is reduced when corrosion of the reinforcing steel is present. However, it is not completely clear how the various components of corrosion (i.e. cracking, rust or chloride) contribute to the signal attenuation at the rebar level. This research seeks to break down each component of corrosion individually and by using computational modeling, investigate the signal attenuation at the rebar level. In addition to previous literature, pieces of a highly corroded bridge deck once in-service were used to understand the physical effects of rebar corrosion. Concrete cracking patterns, rust properties, and chloride contents were all extracted from literature and the bridge deck specimens to most accurately model the corrosion effects. The results indicate that the chloride is the most significant contributor to electromagnetic signal attenuation due to rebar corrosion.


Martino N.,Roger Williams University | Maser K.,Infrasense Inc. | Birken R.,Northeastern University | Wang M.,Northeastern University
Research in Nondestructive Evaluation | Year: 2016

Current visual bridge deck inspection techniques do not provide enough quantitative information about the deck’s deterioration state to support maintenance and rehabilitation decisions. In recent years, ground penetrating radar (GPR) has shown promise in the ability to determine deterioration quantities, with data that can be collected quickly on multiple decks without lane closures. The work presented in this article seeks to develop a method to relate GPR analysis results to the level of active corrosion in a bridge deck. By multiplying the mean and skewness of the rebar reflection amplitudes of a variety of bridge decks, and comparing these values to corrosion quantities based on half-cell potential (HCP) measurements, a master curve with a correlation coefficient of 93% was developed. This article also presents a step-by-step procedure for developing an amplitude threshold for future deck assessments using GPR alone. © 2016 American Society for Nondestructive Testing.


Martino N.,Roger Williams University | Maser K.,Infrasense Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

Current bridge deck condition assessments using ground penetrating radar (GPR) requires a trained analyst to manually interpret substructure layering information from B-scan images in order to proceed with an intended analysis (pavement thickness, concrete cover, effects of rebar corrosion, etc.) For example, a recently developed method to rapidly and accurately analyze air-coupled GPR data based on the effects of rebar corrosion, requires that a user "picks" a layer of rebar reflections in each B-scan image collected along the length of the deck. These "picks" have information like signal amplitude and two way travel time. When a deck is new, or has little rebar corrosion, the resulting layer of rebar reflections is readily evident and there is little room for subjectivity. However, when a deck is severely deteriorated, the rebar layer may be difficult to identify, and different analysts may make different interpretations of the appropriate layer to analyze. One highly corroded bridge deck, was assessed with a number of nondestructive evaluation techniques including 2GHz air-coupled GPR. Two trained analysts separately selected the rebar layer in each B-scan image, choosing as much information as possible, even in areas of significant deterioration. The post processing of the selected data points was then completed and the results from each analyst were contour plotted to observe any discrepancies. The paper describes the differences between ground coupled and air-coupled GPR systems, the data collection and analysis methods used by two different analysts for one case study, and the results of the two different analyses. © 2016 SPIE.


Maser K.R.,Infrasense Inc. | Carmichael A.J.,Infrasense Inc. | Martino N.M.,Northeastern University | Birken R.,Northeastern University
Bridge Maintenance, Safety, Management, Resilience and Sustainability - Proceedings of the Sixth International Conference on Bridge Maintenance, Safety and Management | Year: 2012

The goal of the work reported in this paper is to establish a clearer connection between the electromagnetic response detected with GPR equipment and the elements and stages of the deterioration process. This goal was achieved by conducting comprehensive experimental evaluation of specific bridge deck slabs. These include slabs extracted from in-service structures, controlled slabs specially cast and exposed to corrosion, and actual decks in service. Four decks slabs, saw-cut out of a heavily deteriorated deck, were brought into the lab for evaluation. The slabs were subjected to a full battery of tests, including measurements using hammer sounding, ultrasonic impact-echo (IE), half-cell corrosion potentials (HCP), and ground and air-coupled GPR systems ranging from 1.0 to 2.6 GHz. In parallel with this work, 17 specially constructed laboratory slabs exposed to a controlled corrosion environment over an extended period of time were similarly evaluated to examine the correlation between GPR signals and the level of corrosion. Finally, GPR data collected on inservice decks that were either new or known to be deteriorated was examined to investigate the distribution rebar reflection amplitudes. The multiple methods applied to the extracted deck slabs show a strong correlation. The test results on the controlled slabs showed a correlation between average half cell potentials and GPR rebar reflection amplitudes with an R 2 of 0.85. Finally, the rebar reflection amplitude distributions for the new vs. deteriorated decks showed distinct statistical differences, suggesting that these distribution statistics can serve to identify overall deterioration quantities. © 2012 Taylor & Francis Group.


Hoegh K.,University of Minnesota | Khazanovich L.,University of Minnesota | Maser K.,Infrasense Inc. | Tran N.,National Center for Asphalt Technology
Transportation Research Record | Year: 2012

Delamination that occurs because of layer debonding or stripping between layers of hot-mix asphalt can cause distresses such as longitudinal cracking in the wheelpath and tearing in the surface. Because these distresses cannot be detected by visual inspection of the pavement, highway agencies are interested in finding nondestructive methods for detecting delamination to maintain roadway networks. A study evaluated an ultrasonic tomography device for detecting the type and severity of delamination with various focusing techniques. A comparison of blind ultrasonic tomography testing results versus construction of bonded and debonded conditions showed that ultrasonic tomography could detect delamination between new and old asphalt layers, as well as delamination of lifts within new asphalt pavement. B-and D-scan methods with the focusing technique of synthetic aperture were able to identify delamination between new and old asphalt interfaces, and a new focusing method developed at the University of Minnesota was used to identify delamination within asphalt lifts.


News Article | October 28, 2016
Site: www.prweb.com

Infrasense Inc., one of the leading subsurface detection firms in the nation, recently completed a ground penetrating radar (GPR) survey to map the depth of steel reinforcing bars within the new Loon Mountain Resort bridge in Lincoln, NH. The newly constructed bridge replaces one that was compromised and partially collapsed in 2011 due to high waters of the Pemigewasset River that it spans during Tropical Storm Irene. A temporary bridge has been providing access to the resort during the construction of the new Bridge, which was nearly completed in June 2016, at the time of the survey. The objective of the survey was to map the depth of steel reinforcing bars within the travel lanes and sidewalk to verify the proper concrete cover thickness per the NHDOT 520.3.1.6.3.6 quality assurance specification, which requires that the rebar/concrete cover depth be verified and recorded prior to opening the bridge to traffic. GPR was the preferred method for this survey because of its ability to image accurately measure the location and depth of objects within a material (concrete) without the need for cutting, drilling, or coring. GPR data were collected along the centerlines of the three planned travel lanes and along the centerline of the sidewalk, including the new deck area as well as the approach slabs totaling approximately 1300 linear feet across 4-alignments. The data collection was completed using a 1.5-GHz antenna and a GSSI SIR-20 GPR control unit, providing efficient and accurate results, requiring less than 2-hours to complete. Ground penetrating radar operates by transmitting short pulses of electromagnetic energy into the deck using an antenna that is moved across the concrete surface. These pulses are reflected back to the antenna with an arrival time and amplitude that is related to the location and nature of dielectric discontinuities in the material (air/asphalt or asphalt/concrete, reinforcing steel, etc). For the Loon Mountain Bridge, we were interested in the reflected response of the reinforcing steel, which was used to map the depth. Approximately 4-weeks after the completion of the work, on July 25th, 2016, the new Loon Mountain Resort bridge was opened to traffic. 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


News Article | December 1, 2016
Site: www.prweb.com

Infrasense Inc., one of the leading subsurface detection firms in the nation, recently completed a ground penetrating radar (GPR) survey to map the size and position of the steel reinforcing mesh within an undocumented pier extension at the Midway Airport in Chicago, Illinois. The pier itself was originally designed as a three-column structure, but was constructed as a four-column structure without updated as-built information being recorded. Concerns over the structural effectiveness were raised, and GPR was brought in to identify the reinforcing steel pattern, determine the rebar thickness, and identify the depth of the caisson supporting the fourth column. GPR was the preferred method for this survey because of its ability to accurately measure the location and depth of objects within a material (concrete) without the need for cutting, drilling, or coring. The method is readily mobilized and provides real time information that can be used by the client for immediate verification and scope of work changes. To identify the rebar construction a 1.5-GHz GSSI GPR antenna was used to collect a series of bi-directional lines spaced at 4-inches apart in the vertical direction and 6-inches apart in the horizontal direction. The GPR survey covered four sides of the concrete pier. A 400-MHz antenna was used to map the depth of the caisson by collecting parallel lines surrounding the pier column. The data collection was completed in approximately 4-hours, using equipment that was hand carried to the project area. Ground penetrating radar operates by transmitting short pulses of electromagnetic energy into a concrete structure using an antenna that is moved across the surface. These pulses are reflected back to the antenna with an arrival time and amplitude that is related to the location and nature of dielectric discontinuities in the material (e.g. reinforcing steel). For the concrete pier, GPR measured the reflected response of the reinforcing steel, which was used to map the position and size. The results of our survey were significant as they provided crucial structural information about the integrity of the pier extension, and whether repairs or reconstruction is necessary. Since 1987, Infrasense, Inc. has applied state-of-the-art technologies to address the most difficult challenges in subsurface scanning. Infrasense’s engineers can 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

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