Bridge Scour Monitoring Technologies
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Bridge Scour Monitoring Technologies
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Author : Matthew Lueker
language : en
Publisher:
Release Date : 2010
Bridge Scour Monitoring Technologies written by Matthew Lueker and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Bridges categories.
Bridge failure or loss of structural integrity can result from scour of riverbed sediment near bridge abutments or piers during high-flow events in rivers. In the past 20 years, several methods of monitoring bridge scour have been developed spanning a range of measurement approaches, complexities, costs, robustness, and measurement resolutions. This project brings together the expertise of Minnesota Department of Transportation (Mn/DOT) bridge engineers and researchers, university hydraulic and electrical engineers, field staff, and inspectors to take the first steps toward development of robust scour monitoring for Minnesota river bridges. The team worked with Mn/DOT engineers to identify variables of scour critical bridges that affect the application of scour monitoring technology. The research team will used this information to develop a Scour Monitoring Decision Framework (SMDF) that will aid Mn/DOT in selecting the best technologies for specific sites. The final component of the project will involve testing the SMDF on five bridges in a case-study type demonstration; work plans for two of the sites were developed for demonstration of deployed instrumentation.
Scour Monitoring Technology Implementation
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Author :
language : en
Publisher:
Release Date : 2014
Scour Monitoring Technology Implementation written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Bridges categories.
Bridge scour is the removal of sediment around bridge foundations and can result in the failure of the bridge. Scour monitoring is performed to identify unacceptable scour on bridges considered to be scour critical and determine when scour reaches elevations that could cause potential bridge failure. Two types of monitoring are available: portable monitoring and fixed monitoring. Prior to this project, MnDOT was only using portable monitoring devices, which requires the deployment of personnel to make physical measurements of scour depths. For some scour critical bridges, especially during high-water events, fixed instrumentation capable of continuous scour monitoring was preferred, but MnDOT lacked the experience or expertise to install this type of equipment. This project installed fixed monitoring equipment at two bridge sites and monitored them for three years to determine the effectiveness and reliability of fixed scour monitoring deployments. Several device options were installed to allow MnDOT to analyze the installation and performance of different types of sensors. Both systems operated for the three years with some outages due to various causes but overall performance was acceptable. The outages were mostly related to power issues and communication issues. Valuable lessons were learned through the deployment, which may be applied to future installations. The deployment executed in this project has provided the confidence to deploy other fixed scour monitoring equipment at key bridges around the state of Minnesota. In addition, the data collected during deployment of the scour monitoring equipment has been stored and provides insight into scour processes. This data can be used by other research groups for design or research purposes.
Realtime Monitoring Of Bridge Scour Using Remote Monitoring Technology
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Author : J.-L. Briaud
language : en
Publisher:
Release Date : 2011
Realtime Monitoring Of Bridge Scour Using Remote Monitoring Technology written by J.-L. Briaud and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Bridges categories.
The research performed in this project focuses on the application of instruments including accelerometers and tiltmeters to monitor bridge scour. First, two large scale laboratory experiments were performed. One experiment is the simulation of a bridge with a shallow foundation, and the other is the simulation of a bridge with a deep foundation. A series of instruments were installed on the simulated bridge to monitor the performance of the bridge due to scour. Both the shallow foundation experiment and deep foundation experiment show that accelerometers and tiltmeters can be used in scour monitoring events since both give warning of bridge failure successfully. Subsequently, two individual monitoring systems were designed and installed on two bridges: US59 over Guadalupe River Bridge and SH80 over San Antonio River Bridge in Texas. Realtime data are collected and transmitted to a computer server at Texas A&M University, which can be accessed remotely. The instrumentation on the two bridges does not show great hope of application of accelerometers to monitor bridge scour because of a lack of sufficient excitation from traffic. Another issue with the accelerometers is the high power consumption during the transmission of accelerometer data, which cannot be satisfied with a typical solar panel and battery. Tiltmeters can provide the integral behavior of the bridge, and therefore are very useful devices for scour monitoring. Guidelines and protocols for scour monitoring based on the US59 over Guadalupe River Bridge and the SH80 over San Antonio River Bridge are provided in the study.
White Paper
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Author : David E. Kosnik
language : en
Publisher:
Release Date : 2010
White Paper written by David E. Kosnik and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Scour at bridges categories.
Field Implementation And Evaluation Of The Simple Cost Effective Scour Sensor
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Author : Farhad Ansari
language : en
Publisher:
Release Date : 2011
Field Implementation And Evaluation Of The Simple Cost Effective Scour Sensor written by Farhad Ansari and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Detectors categories.
Field Monitoring Of Scour Critical Bridges
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Author : Xiong Yu
language : en
Publisher:
Release Date : 2010
Field Monitoring Of Scour Critical Bridges written by Xiong Yu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Detectors categories.
Scour is a major threat to the safety of bridges. Instruments for the measurement and monitoring of bridge scour are necessary to study scour processes and to support bridge management. The lack of robust and economical scour monitoring devices prevents the implementation of a bridge scour monitoring program among bridge owners. This project explores the design and analyses of scour sensors using principles of Time Domain Reflectometry (TDR). The performance of a scour probe was first tested in laboratory simulated scour experiments. Three different signal analyses methods were developed to obtain the scour depth from TDR signals. Besides scour depth, additional information related to scour assessment, i.e. sediment density and electrical conductivity of water, were also determined from TDR signals. The sensing principles and analysis algorithms were validated from simulated scour tests under various conditions which are expected to be encountered in the field. The field conditions considered included: variation of sediment types, water conductivity, turbidity, air entrapment, and water elevation. These further validated the robustness of the scour sensing principles. Upon validation, a field worthy sensor was designed. The sampling area and effective measured dielectric constant were determined using a finite element analysis method. Evaluation of the sensor indicated that it was able to successfully monitor the scour processes (scour and refill) in real-time with high accuracy. Six TDR bridge scour sensors were installed at BUT-122-0606 bridge on SR 122 over the Great Miami River in Butler County, with assistance of project partners GRL Engineers Inc., and J&L Laboratories. Automatic monitoring units were installed to automatically take scour sensor signals and wirelessly transmit the sensor data. The sensors were installed using routine geotechnical site investigation tools and procedures. High quality signals were obtained, from which the development of scour adjacent to bridge piers was measured. The results are reasonable. The pilot study points to the promise of this new technology for long term bridge scour monitoring purposes. Continued evaluation and refinement of this new scour monitoring sensor system is highly recommended.
Smart Rocks For Bridge Scour Monitoring
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Author : Andro Radchenko
language : en
Publisher:
Release Date : 2017
Smart Rocks For Bridge Scour Monitoring written by Andro Radchenko and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
"River bridge scour is an erosion process in which flowing water removes sediment materials (such as sand, rocks) from a bridge foundation, river beds and banks. As a result, the level of the river bed near a bridge pier is lowering such that the bridge foundation stability can be compromised, and the bridge can collapse. The scour is a dynamic process, which can accelerate rapidly during a flood event. Thus, regular monitoring of the scour progress is necessary to be performed at most river bridges. Present techniques are usually expensive, require large man/hour efforts, and often lack the real-time monitoring capabilities. In this dissertation a new method - 'Smart Rocks Network for bridge scour monitoring' is introduced. The method is based on distributed wireless sensors embedded in ground underwater nearby the bridge pillars. The sensor nodes are unconstrained in movement, are equipped with years-lasting batteries and intelligent custom designed electronics, which minimizes power consumption during operation and communication. The electronic part consists of a microcontroller, communication interfaces, orientation and environment sensors (such as are accelerometer, magnetometer, temperature and pressure sensors), supporting power supplies and circuitries. Embedded in the soil nearby a bridge pillar the Smart Rocks can move/drift together with the sediments, and act as the free agent probes transmitting the unique signature signals to the base-station monitors. Individual movement of a Smart Rock can be remotely detected processing the orientation sensors reading. This can give an indication of the on-going scour progress, and set a flag for the on-site inspection. The map of the deployed Smart Rocks Network can be obtained utilizing the custom developed in-network communication protocol with signals intensity (RSSI) analysis. Particle Swarm Optimization (PSO) is applied for map reconstruction. Analysis of the map can provide detailed insight into the scour progress and topology. Smart Rocks Network wireless communication is based on the magneto-inductive (MI) link, at low (125 KHz) frequency, allowing for signal to penetrate through the water, rocks, and the bridge structure. The dissertation describes the Smart Rocks Network implementation, its electronic design and the electromagnetic/computational intelligence techniques used for the network mapping"--Abstract, page iii.
Bridge Scour Monitoring Methods At Three Sites In Wisconsin
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Author : J. F. Walker
language : en
Publisher:
Release Date : 2005
Bridge Scour Monitoring Methods At Three Sites In Wisconsin written by J. F. Walker and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Scour at bridges categories.
Of the nearly 11,500 bridges in Wisconsin, 89 have been assessed with critical scour conditions. The U.S. Geological Survey, in cooperation with the Wisconsin Department of Transportation, the Marathon County Highway Department, and the Jefferson County Highway Department, performed routine monitoring of streambed elevations for three bridges. Two monitoring approaches were employed: (1) manual monitoring using moderately simple equipment, and (2) automated monitoring, using moderately sophisticated electronic equipment. The results from all three sites demonstrate that both techniques can produce reasonable measurements of streambed elevation. The manual technique has a lower annual operating cost, and is useful for cases where documentation of long-term trends is desired. The automated technique has a higher annual operating cost and is useful for real-time monitoring of episodic events with short time durations.
Monitoring Of Bridge Stability Due To Scour Using Remote And Low Cost Optical Sensors
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Author : Mohamed Saafi
language : en
Publisher:
Release Date : 2008
Monitoring Of Bridge Stability Due To Scour Using Remote And Low Cost Optical Sensors written by Mohamed Saafi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with Bridges categories.
Scour is the erosion of the stream and banks near foundations, piers and abutments of a bridge which is also referred to as bridge scour. Scour of the bed near bridge piers and abutments has resulted in more bridge failures than all other causes in recent years. Highway bridge failures cost millions of dollars each year as a result of both direct costs necessary to replace and restore bridges, and indirect costs related to disruption of transportation facilities. There are two issues associated with such scour induced damage to bridge pier footings. The first effect is the loss of foundation material which exposes the footing and lowers its factor of safety with regard to sliding or lateral deformation. The greatest loss of sediment to scour occurs at high water velocities, such as during floods. Secondly, pier movement may occur as a result of material loss beside and beneath the base of the footing which produces undesired stresses in the bridge structure and ultimately results in structural collapse. Scour can go undetected for many years until a catastrophic disaster occurs. This problem cannot be entirely eliminated, but can be corrected when scour does occur. A major obstacle in correcting this dilemma is determining when and where the crisis is occurring. Many methods have been used in determining whether or not scour is present. Some of these techniques are permanently attached to the structures and others can be transported from bridge to bridge to measure the scour. Also, some of the current procedures cannot work in some conditions and places. Recently, the National Cooperative Highway Research Program (NCHRP) recognized the need of more research activities to develop, test and evaluate instrumentations that would be both technically and economically feasible for use in monitoring maximum scour depth at bridge piers and abutments. The scour monitoring devices should be low cost, reliable, and capable of installation on or near a bridge pier. Therefore, the objective of this project is to develop a low-cost optical system to detect scour. The proposed optical system was developed and evaluated through large scale scour tests. Results indicated that the proposed sensor is capable of detecting scour depth under flood conditions.
Sensor Development And Response Analysis For Bridge Scour Monitoring And Prognosis
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Author : Faezeh Azhari
language : en
Publisher:
Release Date : 2016
Sensor Development And Response Analysis For Bridge Scour Monitoring And Prognosis written by Faezeh Azhari and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Bridges, as well as off-shore wind turbines and other marine structures, are susceptible to failures due to local scour, which is a dynamic phenomenon that is caused by flowing water removing the bed material from around piles, piers, and abutments. If extended over a critical depth, scour can jeopardize the stability and safety of overwater bridges. In fact, scour is the predominant cause of overwater bridge failures in North America and around the world. Monitoring, as part of bridge maintenance, can prevent scour-induced damage and failure by continuously measuring the extent of scour so that preventative measures can be taken in a timely manner. Over the years, numerous sensing systems have been developed for monitoring bridge scour by measuring scour depth at locations near bridge piers and abutments. Due to the limitations of periodic inspections conducted by trained divers and by using portable instruments, fixed monitoring systems have become the viable solution. Existing fixed scour sensors include sonar systems, float-out devices, and tilt meters, to name a few. These systems each offer unique advantages, but have limitations (e.g., high costs, low reliability, limited accuracy, etc.) that have restricted their implementation in practice. Therefore, attempts to develop more efficient monitoring schemes continue. In this study two novel scour sensing schemes were evaluated. The first uses driven piezoelectric rods to continuously measure scour depth; and in the second, buried dissolved oxygen (DO) optodes detect scour at discrete depths. Laboratory flume experiments were conducted to validate the proposed sensing systems. In the first sensing scheme, piezoelectric rods are driven into the stream bed at a location where scour depths are wanted. As the scour hole extends, the exposed length of the rod changes, causing the flow-induced voltage signal acquired from the sensor to also vary. Scour depth at the sensor location is determined based on the fact that the natural frequency of the cantilevered sensing rod is inversely related to its length. Prototype piezoelectric rods, in which a poly(vinylidene fluoride) (PVDF) polymer strip forms the main sensing component, were designed and developed. Following various preliminary validation tests, extensive laboratory experiments were performed in which the in-house piezoelectric sensing rods were driven into the soil surrounding a mock bridge pier inside a flume simulating scour conditions. The piezo-sensor was calibrated through eigenfrequency analyses. The second sensing system utilized commercially available miniature DO probes. DO levels are very low in streambed sediments, as compared to the standard level of oxygen in flowing water. Therefore, scour depths can be determined by installing sensors to monitor DO levels at various depths along the buried length of a bridge pier or abutment. The measured DO is negligible when a sensor is buried but would increase significantly once scour occurs and exposes the sensor to flowing water. A set of experiments was conducted in which four dissolved oxygen probes were embedded at different soil depths in the vicinity of a mock bridge pier inside a laboratory flume simulating scour conditions. The measured DO jumped to water DO levels once scour exposed the sensing tip of the probes to flowing water, thereby providing discrete measurements of the maximum scour depth. The sensing concepts behind both scour monitoring schemes were confirmed through comparing the detected and observed scour depths. The PVDF-based sensors provide continuous scour depth measurements, as opposed to discrete ones offered by the DO sensing system. Both sensing schemes were also able to detect any subsequent refilling of the scour hole through the deposition of sediments. Following separate analyses of the results, future research is suggested for the two sensing techniques to gain a better understanding of their advantages, shortcomings, and potential applications. In addition to developing and validating the aforementioned scour sensing schemes, research was conducted aimed at creating a practical warning-time based framework for scour sensor response interpretation. First, the general form of the framework, applicable to a wide range of damage detection operations, was developed. The purpose of structural health monitoring (SHM) is to diagnose any damage or malfunction in an engineering system in a timely manner. Timely detection implies that sufficient warning time is given to perform required maintenance to prevent structural failure. Warning time information is therefore very useful in the design and planning of maintenance procedures. The framework developed as part of this research, is a simple and practical tool for predicting warning times given detected damage (i.e. sensor outputs). The framework incorporates a probabilistic analysis of damage progression such that the uncertainty in warning times can also be determined and used for risk-based decision making. To demonstrate the framework’s applicability to scour monitoring, a detailed example was considered, where the progression of bridge scour was obtained through computational fluid dynamics (CFD) simulations using the software Flow-3D. The resulting diagrams from the framework can be used as an effective tool in estimating the warning time and the uncertainty in the warning time given a detected scour depth. The warning information is extremely useful in identifying and planning the required maintenance procedures based on the available resources.