Air-launched GPR Evaluation for Rapid Assessment of MoDOT Bridge Decks

Air-launched GPR Evaluation for Rapid Assessment of MoDOT Bridge Decks
Author: Lesley Sneed
Publisher:
Total Pages: 49
Release: 2015
Genre: Concrete bridges
ISBN:

This study demonstrated the utility of the air launched ground penetrating radar (GPR) tool in terms of evaluating the condition of MoDOT bridge decks. The objective was to confirm that the air-launched GPR tool can be implemented as a part of a long-term program that enables faster, better, and more cost-effective assessments of MoDOT bridge decks. Ten bridge decks were investigated using an air-launched GPR system. Four of the bridge decks investigated were previously investigated using a ground-coupled GPR system, and results from those four bridge decks served as ground truth for the air-launched GPR interpretations. Findings show reasonably good spatial correlation between the ground-coupled GPR and air-launched GPR datasets in terms of deteriorated regions and overall percentages of deteriorated regions in terms of bridge deck surface area. Apparent discrepancies between the air launched and ground-coupled GPR interpretations can be attributed to several factors, including interpolation between adjacent GPR traverses, differences in signal attenuation due to different antenna frequencies, and differences in signal resolution due to different distance from the antenna to the embedded reinforcing steel. Recommendations for optimum acquisition, processing, and interpretation parameters for air-launched GPR reconnaissance-style assessment were provided as part of this study.

Advanced Approaches for Bridge Deck Assessment Using Ground Penetrating Radar

Advanced Approaches for Bridge Deck Assessment Using Ground Penetrating Radar
Author: Aleksey Kamilevich Khamzin
Publisher:
Total Pages: 194
Release: 2015
Genre: Bridges
ISBN:

"Ground penetrating radar (GPR) data were acquired across four bridge decks with the objective of developing an advanced workflow for GPR operation that would allow the bridge owners to estimate repair quantities for certain bridge decks, based on GPR data. The primary contributions from this research are as follows: 1. It was demonstrated that the conditions of bridge decks can be cost-effectively and efficiently assessed using the GPR tool. 2. The GPR tool's ability to provide rapid and reliable results in comparison with conventional bridge deck condition assessment techniques was established. 3. The qualitative and quantitative relationships between the GPR reflection amplitude and depth of concrete degradation were analyzed to develop an effective technique to estimate the amount of deteriorated concrete present in a particular bridge deck; this technique could enable bridge owners to use the GPR tool (only) to estimate the thickness of concrete that would be removed by processes such as hydro demolition. 4. The air-launched and ground-coupled GPR systems were compared in terms of accuracy of data acquisition and reliability of results. It was determined that air-launched GPR is a reliable tool for the fast and cost-effective assessment of bridge decks. This work is new and important because it extends the traditional use of the GPR technique and presents the advanced approach for data interpretation and concrete material removal estimation, especially in areas where deterioration was not visually exposed"--Abstract, page iii.

Nondestructive Evaluation of MoDOT Bridge Decks. N Phase 2

Nondestructive Evaluation of MoDOT Bridge Decks. N Phase 2
Author: Lesley Sneed
Publisher:
Total Pages: 356
Release: 2014
Genre: Concrete bridges
ISBN:

This research has examined the use of nondestructive techniques for concrete bridge deck condition assessments. The primary nondestructive testing/evaluation (NDT/NDE) technique utilized in this research was ground-coupled ground penetrating radar (GPR). The objectives of this research were to examine the utility of the nondestructive techniques in evaluating the condition of MoDOT bridge decks to enable faster, better, and more cost-effective bridge deck assessments, and to determine the accuracy of the information provided.

Application of Ground Penetrating Radar (GPR) for Bridge Deck Condition Assessment: Using a 1.5 GHz Ground-coupled Antenna

Application of Ground Penetrating Radar (GPR) for Bridge Deck Condition Assessment: Using a 1.5 GHz Ground-coupled Antenna
Author: Amos Wamweya
Publisher:
Total Pages: 0
Release: 2009
Genre: Bridges
ISBN:

"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

Ground Penetrating Radar for Concrete Bridge Deck Evaluation

Ground Penetrating Radar for Concrete Bridge Deck Evaluation
Author: Daniel E. Diaz
Publisher:
Total Pages: 308
Release: 2018
Genre:
ISBN:

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.

Nondestructive Testing to Identify Concrete Bridge Deck Deterioration

Nondestructive Testing to Identify Concrete Bridge Deck Deterioration
Author:
Publisher: Transportation Research Board
Total Pages: 96
Release: 2013
Genre: Technology & Engineering
ISBN: 0309129338

" 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.

Ground-penetrating Radar

Ground-penetrating Radar
Author: Lawrence B. Conyers
Publisher: Altamira Press
Total Pages: 238
Release: 1997
Genre: Science
ISBN:

Traditional archaeological excavation methods are sometimes daunting due to political or financial complications. Other times, an improperly planned dig can destroy or entirely overlook the features or artifacts being sought. In either case, Ground-Penetrating Radar, or GPR, is an increasingly applicable technology, but one that few archaeologists truly understand. That is where this book excels. It is tailored towards an archaeological community which is for the most part apprehensive about using "high tech" instruments and feel more comfortable on their hands and knees digging in the dirt. Its abundant illustrations and easy-to-understand tables help to keep this potentially daunting subject matter accessible. It also contains more complex equations and theory so that the more technically-oriented can use it as a reference tool.

Forensic Engineering

Forensic Engineering
Author: Alicia Díazde León
Publisher:
Total Pages: 0
Release: 2012-11
Genre: Civil engineering
ISBN: 9780784412640

Proceedings of the Sixth Congress on Forensic Engineering, held in San Francisco, California, October 31-November 3, 2012. Sponsored by the Technical Council on Forensic Engineering of ASCE. This collection contains 144 peer-reviewed papers presenting findings intended to help forensic engineers develop practices and procedures to reduce the number of failures, disseminate information on failures, and provide guidelines for conducting failure investigations and for ethical conduct. Topics include: bridges; building envelopes; critical infrastructure; design practices; disaster risk management; education; emerging technologies; fires; floods; flooring; geotechnical failures; hurricanes, tornadoes, and extreme winds; investigative methodologies; practices to reduce failures; professional practice; research and testing; residential construction; and structural failures. This will be valuable to engineers, researchers, educators, and students involved in forensic engineering.

Computer Organization and Design RISC-V Edition

Computer Organization and Design RISC-V Edition
Author: David A. Patterson
Publisher: Morgan Kaufmann
Total Pages: 700
Release: 2017-05-12
Genre: Computers
ISBN: 0128122765

The new RISC-V Edition of Computer Organization and Design features the RISC-V open source instruction set architecture, the first open source architecture designed to be used in modern computing environments such as cloud computing, mobile devices, and other embedded systems. With the post-PC era now upon us, Computer Organization and Design moves forward to explore this generational change with examples, exercises, and material highlighting the emergence of mobile computing and the Cloud. Updated content featuring tablet computers, Cloud infrastructure, and the x86 (cloud computing) and ARM (mobile computing devices) architectures is included. An online companion Web site provides advanced content for further study, appendices, glossary, references, and recommended reading. Features RISC-V, the first such architecture designed to be used in modern computing environments, such as cloud computing, mobile devices, and other embedded systems Includes relevant examples, exercises, and material highlighting the emergence of mobile computing and the cloud

Failure, Distress and Repair of Concrete Structures

Failure, Distress and Repair of Concrete Structures
Author: Norb Delatte
Publisher: Elsevier
Total Pages: 352
Release: 2009-10-26
Genre: Technology & Engineering
ISBN: 1845697030

Understanding and recognising failure mechanisms in concrete is a fundamental pre-requisite to determining the type of repair, or whether a repair is feasible. This title provides a review of concrete deterioration and damage, as well as looking at the problem of defects in concrete. It also discusses condition assessment and repair techniques. Part one discusses failure mechanisms in concrete and covers topics such as causes and mechanisms of deterioration in reinforced concrete, types of damage in concrete structures, types and causes of cracking and condition assessment of concrete structures. Part two reviews the repair of concrete structures with coverage of themes such as standards and guidelines for repairing concrete structures, methods of crack repair, repair materials, bonded concrete overlays, repairing and retrofitting concrete structures with fiber-reinforced polymers, patching deteriorated concrete structures and durability of repaired concrete. With its distinguished editor and international team of contributors, Failure and repair of concrete structures is a standard reference for civil engineers, architects and anyone working in the construction sector, as well as those concerned with ensuring the safety of concrete structures. Provides a review of concrete deterioration and damage Discusses condition assessment and repair techniques, standards and guidelines