The Interpretation Of Ultrasonic Wave Signals Received From Concrete Bridge Decks With Simulated Cracks Using Ultrasonic Pulse Velocity Technique
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The Interpretation Of Ultrasonic Wave Signals Received From Concrete Bridge Decks With Simulated Cracks Using Ultrasonic Pulse Velocity Technique
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Author : Liz Jean Zea Garavito
language : en
Publisher:
Release Date : 1997
The Interpretation Of Ultrasonic Wave Signals Received From Concrete Bridge Decks With Simulated Cracks Using Ultrasonic Pulse Velocity Technique written by Liz Jean Zea Garavito and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with Bridges categories.
Master S Theses Directories
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Author :
language : en
Publisher:
Release Date : 2000
Master S Theses Directories written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Dissertations, Academic categories.
"Education, arts and social sciences, natural and technical sciences in the United States and Canada".
Materials Evaluation
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Author :
language : en
Publisher:
Release Date : 1996
Materials Evaluation written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1996 with Materials categories.
Application Of Artificial Neural Networks To Ultrasonic Pulse Echo System For Detecting Microcracks In Concrete
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Author : A. Michael Alexander
language : en
Publisher: Washington, DC : U.S. Army Corps of Engineers
Release Date : 1998
Application Of Artificial Neural Networks To Ultrasonic Pulse Echo System For Detecting Microcracks In Concrete written by A. Michael Alexander and has been published by Washington, DC : U.S. Army Corps of Engineers this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Alkali-aggregate reactions categories.
Concrete deterioration standards containing various levels of microcracks were engineered by adding calcium sulfate to the concrete mixture and curing under moisture at 38 deg. C (100 deg. F). The level of the mircocracks was classified according to the speed of the ultrasonic pulse velocity (UPV) through the specimens using the American Society for Testing and Material (ASTM) C 597 (ASTM 1994c) test method and was found to vary uniformly from 1,737 to 4,877 m/sec (5,700 to 16,000 ft/sec). After receiving some preprocessing, 186 ultrasonic pulse echo (UPE) signals were used as input training examples for the artificial neural network (ANN) system. Target values for the ANN were the measured UPVs as determined form the ASTM C 597 test method. The correlation coefficient from a least squares fit was 98.6 percent. After training, the ANN was performance tested with 30 UPE signals that the model had not seen in training. A least squares fit demonstrated that the output velocities from the ANN correlated well with the measured (target) UPVs. The correlation coefficient was 84.8 percent. The system was able to rank all six specimens in the correct order of deterioration. This investigation demonstrates that the automated interpretation of UPE signals for continuous interfaces by the ANN is feasible.
Application Of Artificial Neural Networks To Ultrasonic Pulse Echo System For Detecting Microcracks In Concrete
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Author : A. Michel Alexander
language : en
Publisher:
Release Date : 1998
Application Of Artificial Neural Networks To Ultrasonic Pulse Echo System For Detecting Microcracks In Concrete written by A. Michel Alexander and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Alkali-aggregate reactions categories.
Effectiveness Of Ultrasonic Pulse Velocity And Impact Echo Ndt Techniques To Assess The Quality Of Concrete
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Author : Shibli Russel Mohiuddin Khan
language : en
Publisher:
Release Date : 2002
Effectiveness Of Ultrasonic Pulse Velocity And Impact Echo Ndt Techniques To Assess The Quality Of Concrete written by Shibli Russel Mohiuddin Khan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with Concrete categories.
The deterioration of concrete in structure is a result of several internal or external degradation mechanism and which results in distress of the structure i.e. decrease in strength and integrity of the structure. the state of distress is often hidden from view and is only evident at a stage where there is significant reduction in strength of the structure. defects are open introduced during construction and are viewed during in services life. Some deterioration is viewed physically in the early age or during the services life of the structure in terms of spalling, surface crack, swelling and honeycombing. This deterioration collectively or individually results in reducing the load carrying capacity in terms of the distress of the structure. In this project, the common defects in the concrete structures and mapping techniques by nondestructive test are presented. Among the various techniques of the nondestructived tests, the Ultrasonic Pulse Velocity (UPV) and DOCtor's impact echo were chosen for their effectiveness. The UPV is used to estimate the concrete strength, detecting flaws such as voids and cracks and also to investigate the effects of smaller diameter bar in the concrete. In detecting various sizea of voids by the Impact-echo test techiniques a format was suggested to identify the from the frequency spectrum. In the bridge condition assessment by nondestructive test techniques most common problem encountered were correlationof cube crushing strength to the UPV values, in order to determine residual strength of the structure in different enviromental conditions. also the other defects such as cracks and voids in the concrete, which does not have any standard guideline to identify them by theabove NDT techniques to use in the bridge condition assessment. This project has dealt with large number of specimens between the actual condition and those of the values given by the NDT results. A number of beam specimens were also cast with known defects in the concrete in order to obtain and suggest standard investigation procedure. 108 standard cubes with different grades and enviromental conditions were cast. Also eight beams and a slab were casting having known common defects. From the strength- UPV correlation nine numbers of regression equations were suggested. A standard transducer spacing has been suggested for detecting crack depth of to 50 to 125mm range. The effect of bar sizes on UPV test results was also obtained. Reinforced concrete slabs or decks having bar diameter greater than 10mm diameter will be affect the reading of UPV. Based on the obtained resuls a computer database system for NDT has been made to accomodate and fulfill necessary requirements of knowledge base system. Hence this knowledge base system will be used for bridge condition assessment.
Application Of Seismic Surface Waves In Concrete Bridge Deck Evaluation
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Author : Farhad Fetrat
language : en
Publisher:
Release Date : 2016
Application Of Seismic Surface Waves In Concrete Bridge Deck Evaluation written by Farhad Fetrat and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Concrete bridges categories.
Accurate and timely condition assessment of bridge decks is essential for economic management of aging highway bridges. The ability to evaluate concrete modulus profile in a bridge deck can help the detection of early signs of deterioration and optimize the bridge maintenance procedures. This study presents a new method for modulus profiling of concrete bridge decks. The stiffness matrix method is used to simulate wave propagation in a layered media. The results are compared to numerical finite element models. Dispersion analysis is done using the multi-channel analysis of surface waves (MASW) and phase-shift methods. The characteristics of dispersion surface are analyzed and the effects of model parameters on dispersion surface are examined through a series of parametric studies. An inversion technique is proposed for a fast inversion of surface-wave data collected on bridge decks. This technique utilizes a database of pre-calculated dispersion surfaces and takes advantage of the observed patterns in the parametric study as a priori information for the inversion process.
Monitoring Of Pre Stressed Concrete Bridges By Ultrasonic Pulse Velocity Method
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Author :
language : en
Publisher:
Release Date : 1998
Monitoring Of Pre Stressed Concrete Bridges By Ultrasonic Pulse Velocity Method written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Concrete categories.
Ultrasonic Nondestructive Evaluation And Imaging Of Defects In Reinforced Cementitious Materials
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Author : Ji-yong Wang
language : en
Publisher:
Release Date : 2003
Ultrasonic Nondestructive Evaluation And Imaging Of Defects In Reinforced Cementitious Materials written by Ji-yong Wang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with categories.
Characterization of defect is one of the important objectives of nondestructive evaluation (NDE) for condition assessment of structures. Among many other NDE techniques, ultrasonic methods play a prominent role in the both quantitative and qualitative assessment of discontinuities in reinforced cementitious materials. Due to the heterogeneous nature of concrete, ultrasonic waves are highly scattered and attenuated, leading to the difficulty of concrete inspection using conventional ultrasonic techniques, including those that work well on relatively homogeneous materials such as metals. This thesis presents an advanced method for sizing and imaging of defects in reinforced cementitious materials. A two-dimensional, three-phase composite model of concrete is proposed to study the propagation and interaction behaviors of ultrasonic waves in concrete structures, and to gain a knowledge about wave diffraction with multiple cylindrical obstacles. The response of the modeled concrete structure to an incident ultrasonic pulse input signal (pulsed ultrasonic P-wave) is analytically investigated and simulated. A characteristic profile of the defect sizing as a function of focal depth is formulated via the synthetic focusing technique. A defect sizing parameter, called characteristic width, is obtained empirically to represent the defect sizing information for the concrete. Conventional 2-D ultrasonic B-scan imaging, for example, by migration, may introduce artifacts. In this thesis, the fundamental theory for synthetic aperture beam-forming through synthetic steering and focusing of array transducers is investigated. It is possible to achieve high spatial and temporal resolution ultrasonic image free of artifacts. A time-frequency signal processing and image reconstruction algorithm are also studied. The proposed defect sizing and imaging methodology is tested with numerically simulated ultrasonic waveform signals based on the mechanical properties of a custom-made concrete specimen. Experimental works confirm the feasibility of defect sizing and imaging of the method. With the knowledge about the concrete structures being tested this method may provide a useful tool for ultrasonic NDE application to reinforced cementitious materials.
Continuous Long Term Health Monitoring Using Ultrasonic Wave Propagation
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Author : Ece Erdogmus
language : en
Publisher:
Release Date : 2016
Continuous Long Term Health Monitoring Using Ultrasonic Wave Propagation written by Ece Erdogmus and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Composite materials categories.
"This report presents the findings of a research project on using ultrasonic testing to continuously monitor reinforced concrete bridge decks for the onset of delamination. The report first presents a review of current nondestructive testing techniques used in practice and research, and deficiencies of these methods. Then the novel method developed in this project to identify early delamination in reinforced concrete bridge decks is presented. This method uses a unique sensor setup compared to current ultrasonic testing methods and utilizes the waves leak into the concrete from the rebar that is excited with ultrasonic waves" (page 9).