Performance of Ground-penetrating Radar in Indicating Deterioration in Concrete Bridge Decks PDF Download

Author: Jeffrey Scott Klein
Publisher:
ISBN:
Category : Concrete bridges
Languages : en
Pages : 264

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Author: Christopher L. Barnes
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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The Penetradar Integrated Radar Inspection System (IRIS) Ground Penetrating Radar (GPR) was selected by Dalhousie University DalTech as the most appropriate technology for assessing the condition of reinforced concrete bridge decks because of the ability of the system to penetrate through asphalt concrete overlays and Perform data collection at traffic speeds up to 75-80 km/hr. A collaborative research program was designed by Dalhousie University DalTech and the Nova Scotia Department of Transportation and Public Works to examine the accuracy and confidence with which GPR can be used to predict the quantity and location of laminations and concrete scaling On asphalt covered bridge decks. Seventy-two bridge decks were surveyed at traffic speeds using GPR for deterioration estimation. The GPR data was processed manually to determine areas of excess signal attenuation and areas of high concrete relative dielectric constant. Deterioration predictions made using GPR were also compared quantitatively and spatially to ground-truthing data obtained from nine bridge decks using the well-established chain drag and half-cell potential surveys after the asphalt was removed from each bridge deck just prior to repair.

Author: Christopher L. Barnes
Publisher:
ISBN:
Category :
Languages : en
Pages : 406

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Author:
Publisher: Transportation Research Board
ISBN: 0309129338
Category : Technology & Engineering
Languages : en
Pages : 96

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" TRB's second Strategic Highway Research Program (SHRP 2) Report S2-R06A-RR-1: Nondestructive Testing to Identify Concrete Bridge Deck Deterioration identifies nondestructive testing technologies for detecting and characterizing common forms of deterioration in concrete bridge decks.The report also documents the validation of promising technologies, and grades and ranks the technologies based on results of the validations.The main product of this project will be an electronic repository for practitioners, known as the NDToolbox, which will provide information regarding recommended technologies for the detection of a particular deterioration. " -- publisher's description.

Author: Daniel E. Diaz
Publisher:
ISBN:
Category :
Languages : en
Pages : 308

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As the nation's infrastructure continues to age, there is a need to effectively and economically monitor and inspect bridges. With the introduction of non-destructive testing technologies such as Ground Penetrating Radar (GPR) for condition assessment of bridge decks, states will be better equipped to inspect, assess, and prioritize transportation funding to maintain, preserve, and improve infrastructure. The objective of the research is to improve the condition assessment of bridge decks through the use of GPR which can increase the speed, effectiveness, and accuracy of inspections. The non-destructive evaluation technique provides information that can be used to identify the potential amount of internal deterioration of a concrete bridge deck that cannot be identified with a visual inspection. As in many other states, New Mexico currently uses the chain drag method in which the inspection of the deck condition is solely based on inspector's subjective interpretation of the sound produced by dragging a chain over the bridge deck. The use of GPR has the potential to greatly improve the quality of the inspections by collecting more reliable and less subjective information on the condition of bridge decks. Through the collection and analysis of data acquired from the GPR on a set of reinforced concrete decks, this research seeks to provide a better understanding of GPR technology, data acquisition, and training needs for adoption of GPR in bridge deck inspections in the state of New Mexico. With a better understanding of the technology, GPR can become and indispensable tool for more informed decisions for the allocation of funds for maintenance and improved asset management. This research improves implementation and provides effective economic methods to employ this technology to improve the inspection and maintenance of bridge infrastructure.

Author: Christopher Franklin Wright
Publisher:
ISBN: 9781124648781
Category : Concrete bridges
Languages : en
Pages : 63

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Author: Amos Wamweya
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 108

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"This study is a GPR-based assessment of three bridge decks, two with a hot bituminous wearing surface and one with a bare concrete slab. The primary objectives of this study were: 1) to assess the integrity of the three bridge decks using a 1.5 GHz ground-coupled GPR antenna, and 2) to evaluate the utility of the 1.5 GHz ground-coupled antenna for bridge deck investigations. Core control (chloride ion concentration data and core integrity data) and visual inspection were used as interpretive constraint. The acquired GPR data were interpreted, and two plan view maps were generated. One depicts the magnitude of the reflections from the uppermost mat of rebar, and the second shows the arrival time of these reflections. Analysis of the GPR data and core control indicates that the magnitude of the reflected GPR signal from the uppermost mat of rebar is a direct function of concrete integrity. Higher magnitude reflections indicate higher quality concrete. To a lesser extent, the arrival time of the reflected energy is also indicative of concrete quality. Faster arrival times generally indicate higher quality concrete. Exceptions to this rule occur where the depth to the top layer of rebar varies. In this study, relative reflection amplitudes of less than 3000 on the bare concrete bridge and less than 5000 on the bituminous surface bridges indicate severe deterioration. Core control data was interpreted based on chloride ion corrosion threshold. Corrosion of rebar occurs once chloride ions content adjacent to the rebar reaches a threshold of approximately 0.033% to 0.04% by weight of concrete (or 330 ppm to 400 ppm). The GPR data correlates well with the core control, indicating that the 1.5 GHz antenna is an effective tool for assessing the condition of bridge decks"--Abstract, leaf iii.

Author: Gerardo G. Clemeña
Publisher:
ISBN:
Category : Concrete bridges
Languages : en
Pages : 22

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It was shown in a previous study that the presence of delamination in concrete can be detected by the appearance of a distinctive signature in the analog radar reflection profiles recorded when a concrete deck is scanned with ground-penetrating radar. As a follow-up, radar was used on eleven overlaid bridge decks to assess the overall reliability of the technique when applied to the nondestructive inspection of such decks, using the identified radar signature as an indicator of the presence of concrete delamination. The radar results were verified by soundings conducted on the test decks after their overlays were removed. Among the decks tested, the average success rate of radar in detecting real concrete delamination was found to be 82 ± 20 percent (at 95 percentile). In addition, false indication of the presence of delamination had been observed. It was suspected, however, that the presence of debonding and damage in the overlay in some locations contributed extensively to this type of errors since such damages in the decks would likely manifest themselves as anomalies in the reflection profiles close to that associated with concrete delamination. On the other hand, although some concrete delaminations were missed by radar, these misses often involved relatively small delaminated areas. For future studies, it is recommended that additional radar parameters (including localized increased reflectivity at the bituminous/concrete interface, polarity change in the reflection at the interface, distortions in the reflection from the rebars, and attenuation of reflection from the concrete slab) be examined. These parameters can be related to other types of damages often found in overlaid decks in conjunction with the concrete delaminations.

Author: Kien Dinh
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Ahmad Shami
Publisher:
ISBN:
Category :
Languages : en
Pages : 138

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The ASCE report card 2013 rated bridges at a grade of C+, implying their condition is moderate and require immediate attention. Moreover, the Federal Highway Administration reported that it is required to invest more than $20.5 billion each year to eliminate the bridge deficient backlog by 2028. In Canada 2012, more than 50% of bridges fall under fair, poor, and very poor categories, where more than $90 billion are required to replace these bridges. Therefore, government agencies should have an accurate way to inspect and assess the corrosiveness of the bridges under their management. Numerical Amplitude method is one of the most common used methods to interpret Ground Penetrating Radar (GPR) outputs, yet it does not have a fixed and informative numerical scale that is capable of accurately interpreting the condition of bridge decks. To overcome such problem, the present research aims at developing a numerical GPR-based scale with three thresholds and build deterioration models to assess the corrosiveness of bridge decks. Data, for more than 60 different bridge decks, were collected from previous research works and from surveys of bridge decks using a ground-coupled antenna with the frequency of 1.5 GHz. The amplitude values of top reinforcing rebars of each bridge deck were classified into four categories using k-means clustering technique. Statistical analysis was performed on the collected data to check the best-fit probability distribution and to choose the most appropriate parameters that affect thresholds of different categories of corrosion and deterioration. Monte-Carlo simulation technique was used to validate the value of these thresholds. Moreover, a sensitivity analysis was performed to realize the effect of changing the thresholds on the areas of corrosion. The final result of this research is a four-category GPR scale with numerical thresholds that can assess the corrosiveness of bridge decks. The developed scale has been validated using a case study on a newly constructed bridge deck and also by comparing maps created using the developed scale and other methods. The comparison shows sound and promising results that advance the state of the art of GPR output interpretation and analysis. In addition, deterioration models and curves have been developed using Weibull Distribution based on GPR outputs and corrosion areas. The developed new GPR scale and deterioration models will help the decision makers to assess accurately and objectively the corrosiveness of bridge decks. Hence, they will be able to take the right intervention decision for managing these decks.