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.

The purpose of this study was to evaluate the reproducibility and accuracy of Ground Penetrating Radar (GPR) in locating delaminations and de-bonding in asphalt concrete overlaid concrete bridge decks. The traditional "chaining" method is a less effective option for finding subsurface defects after an overlay is in place. An infrared thermographic and GPR evaluation was conducted on the I-70 Polk-Quincy viaduct in 1993. A second GPR study was performed in 1997 to evaluate the condition of the bridge deck previous to removal of the existing asphalt overlay and high density concrete overlay and repair of the deteriorated deck. The results of the 1997 GPR study were compared to the results of the 1993 GPR study, the 1998 through 1999 chaining, actual repair areas and portions of the 1989 Geotechnical Unit bridge deck evaluation.

This synthesis will be of interest to state Department of Transportation (DOT) geotechnical, bridge, and pavement engineers, engineering geologists, consultants involved with ground penetrating radar (GPR) investigations for state DOTs, and researchers. It describes the current state of the practice of using GPR for evaluating subsurface conditions for transportation facilities. This was accomplished by conducting a literature search and review and an extensive survey of U.S. and Canadian transportation agencies and practitioners, as well as limited international information collection. GPR is a noninvasive nondestructive tool used in transportation applications such as evaluation and characterization of pavement systems, soils, and environmental problems. This report of the Transportation Research Board presents information on the principles, equipment, logistics, applications, and limitations of GPR pertaining to transportation applications. Selected case studies for which ground truth information is available are presented. In addition, an extensive bibliography and glossary are provided as well as appending information about GPR manufacturers from their literature.

Structural health monitoring (SHM) uses one or more in situ sensing systems placed in or around a structure, providing real-time evaluation of its performance and ultimately preventing structural failure. Although most commonly used in civil engineering, such as in roads, bridges, and dams, SHM is now finding applications in other engineering envir

This book is a collection of papers presented in the NDT Conference held on February 20-23, 1996 at San Diego, California. The conference provided an opportunity to share experience and provide additional input to the Federal Highway Administration.

The fourth Structural Materials Technology NDT Conference was held in Atlantic City, New Jersey, with over sixty speakers presenting on a wide variety of topics. The goal of this conference was to inform engineers and researchers of the new nondestructive testing/nondestructive evaluation (NDT/NDE) technologies and techniques available for use in transportation construction. The use of alternative materials is challenging NDT/NDE professionals to develop new methods or modify existing techniques to address quality control, quality assurance, and long-term monitoring of structures built or strengthened with these materials. One such alternative is fiber-reinforced polymer (FRP) products. This conference included papers on this topic and a panel discussion that focused on the future of NDT/NDE technologies for structures built or rehabilitated with FRP composites. These proceedings contain the 62 papers that were presented at the conference, arranged according to session number. An author index is included.

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.

Effective maintenance of bridge structures comprises a broad spectrum of plans for repairs and services implemented to enable bridges to perform their intended function. These include in-depth inspection, fatigue analysis, design of mitigation measures and construction to avert component deterioration. Several incidents of in-service and under construction bridge failures have recently taken place. These dramatic failures emphasize the importance of risk-based inspections and analysis of real-life data to evaluate reliability of bridges. To effectuate benefits of reliability analysis in bridge maintenance, work on theoretical reliability must be equipped with practical analytical tools. Such an approach must underscore risk elements and identify processes to manage risk and avoid unexpected outcomes of failures and service disruption of bridges. The devastating earthquakes of February 6, 2023, in the southern region of Turkey near the northern border of Syria, which claimed tens of thousands of lives, caused enormous structural damage and staggering economic losses. These seismic events brought to focus on the vitality of instilling infrastructure routes that must accommodate emergency management plans to integrate the influx of medical and rescue response teams. The safe operation of bridges along these routes is indispensable for mobilization and deployment of rescue teams, medical personnel, humanitarian assistance, and the supply of food and water. The reliability of access routes and bridges is defined by their ability to adequately function as planned to effectuate emergency management plans, in the event of a similar seismic event, anywhere in the world. Risk-Based Strategies for Bridge Maintenance contains selected papers presented at the 11th New York City Bridge Conference (New York City, USA, 21-22 August 2023), and discusses issues of reliability, risk assessment, management, maintenance, inspection, monitoring, design, preservation, and rehabilitation of bridges. The book is aimed at bridge engineers.