Download or read book Monitoring Bridge Scour with Buried Transmitters written by Walter A. Winter and published by . This book was released on 1995 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monitoring Bridge Scour with Buried Transmitters written by Walter A. Winter and published by . This book was released on 1995 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridge scour is the major cause of bridge failure. Scour occurs when waterways are at high stage and the rock and sediments that support bridge piers are removed by water action. Monitoring and quantifying scour is considered a high priority problem by the Caltrans Division of Structures. A conceptual design was developed which would use buried scour sensors placed at known depths in drilled holes. They would sense by tilting when scour reached their depth and would transmit that information to the surface with low frequency radio. A design was conceptualized, and Stolar Research Group of Raton, New Mexico, submitted a proposal to build the concept system. Stolar Research's technical discussion and proposal constitute the technical content of this report and appear as an appendix.
Download or read book Monitoring Scour Critical Bridges written by Beatrice E. Hunt and published by Transportation Research Board. This book was released on 2009 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sensor Development and Response Analysis for Bridge Scour Monitoring and Prognosis written by Faezeh Azhari and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Remote Sensing for Bridge Scour written by Peter J. Hawrylak and published by . This book was released on 2009 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this research was to create a prototype system for bridge scour monitoring that would provide continuous monitoring. The technique utilized for this particular bridge scour monitoring was detection using float out devices. The float out device concept is to bury transmitters at various locations around a bridge structure. These devices would then be released due to the scour's removal of material around the device. A receiver on the bridge would receive the transmission and perform an action. A float out device system would provide an initial indication of scour severity for further investigation. This document contains all analysis leading up to the system design as well as the rationale behind design decisions made. An initial assessment of what the Scour Monitoring System would be composed of and its functionality is found in the requirements section. A less technical overview of the system designed to meet those requirements can be found in the specifications section. Following this are design sections explaining the system design in detail. Lastly, the implementation and testing of the system is presented. This document also contains all items related to the system such as Bill of Parts, Schematics, Layouts, and Embedded Software Code.
Download or read book Instrumentation for Measuring Scour at Bridge Piers and Abutments written by Peter Frederick Lagasse and published by Transportation Research Board. This book was released on 1997 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This report contains the findings of a study undertaken to develop, test, and evaluate fixed devices for measuring maximum scour depth. Companion manuals provide specific fabrication, installation, and operation guidance for two such devices. This report and the companion manuals will be of immediate interest to hydraulics engineers, bridge management engineers, and bridge maintenance engineers"--Foreward.
Download or read book Stream Stability and Scour at Highway Bridges written by Everett V. Richardson and published by ASCE Publications. This book was released on 1999-01-01 with total page 1076 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sponsored by the Water Resources Engineering (Hydraulics) Divsion of ASCE. This collection contains 75 papers and 321 abstracts presented at conferences sponsored by the Water Resources Engineering (Hydraulics) Division of ASCE from 1991 through 1998. The collection contains many new and expanded versions of the original papers and is designed to assist the practitioner with the concepts in evaluating stream instability and scour at bridges. Topics include: history of bridge scour research; bridge scour determination; stream stability and geomorphology; construction scour; instrumentation for measuring and monitoring; field measurement; computer and physical modeling of bridge scour; scour at culverts; and economic and risk analysis. One important paper contains 384 field measurements of local scour at piers made by the U.S. Geological Survey.
Download or read book Evaluation of Bridge Scour Monitoring Methods written by Joseph C. Davis and published by . This book was released on 2003 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AUTOMATED SCOUR DETECTION ARRAYS USING BIO INSPIRED MAGNETOSTRICTIVE FLOW SENSORS written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Scour is the most common cause of catastrophic bridge failures worldwide. Approximately over 60% of bridge failures reported in the United States from 1966 to 2005 are scour related. To ensure the continued safe operation of bridges, monitoring bridge scour is of paramount importance. Most monitoring regimes that are widely used are based on expensive underwater instrumentation. This research focuses on scour detection using automated remote flow detection arrays based on bio-inspired flow sensors. This study employs an array of bio inspired flow sensors that are inexpensive and robust versions of buried-rod scour sensor arrays, coupled with low-power wireless sensor network utilizing civil-engineering domain wireless sensing units to detect scour around bridge piers and abutments. Sensors within the network that report dynamic flow signals are considered to be waterborne or located above the sediment and sensors reporting static signals are characterized as buried or as being located in sediment. The a priori information of sensor depth will help to establish the sediment level in real time. An automated data interrogation system collects data, processes the raw sensor data using in-network data interrogation methods, then and communicates the results to the on-site base station. The relative directness of this data interrogation adds to the robustness of the system. The main purpose of the scour detection system is to provide remote scour information to bridge owners in a format that is easy to comprehend as an aid in decision making. In this project, only processed results, not raw data, are transmitted to the user. The system under study utilizes a cellular data link to relay simplified data to the bridge owner to aid in decision making. A robust program of validation has been conducted to define the limits of the approach in the laboratory and the results of the laboratory validation experiments have been presented in this thesis. This thesis also illustrates the ongoing initial field installation of scour monitoring system on local bridges with some scour concern.
Download or read book Proceedings of the Bridge Scour Symposium written by and published by . This book was released on 1989 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pilot Installation of a Bridge Scour Monitoring Site at FM 1157 Mustang Creek written by José Weissmann and published by . This book was released on 1999 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Remote bridge scour monitoring written by Thomas Joseph Groll and published by . This book was released on 1999 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monitoring Bridge Scour Using Fiber Optic Sensors written by Chunsheng Cai and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Innovative Grant written by Athanasios Papanicolaou and published by . This book was released on 2010 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The code is written for Windows XP operational system which has a user-friendly windows interface that provides detailed information regarding the smart particle that includes: identification number, location (orientation in x,y,z), and the instance the particle was detected. These systems were examined within the context of this innovative research in order to identify the best suited RFID system for performing autonomous bridge scour monitoring. A comprehensive laboratory study that included 142 experimental runs and limited field testing was performed to test the code and determine the performance of each system in terms of transponder orientation, transponder housing material, maximum antenna-transponder detection distance, minimum inter-particle distance and antenna sweep angle. The two RFID systems capabilities to predict scour depth were also examined using pier models.
Download or read book Instrumentation for Measuring Scour at Bridge Piers and Abutments written by Everett V. Richardson and published by . This book was released on 1992 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Portable Scour Monitoring Equipment written by James Douglas Schall and published by Transportation Research Board. This book was released on 2004 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction and research approach -- Findings -- Interpretation, appraisal, and applications -- Conclusions and suggested research -- References -- Appendixes.
Download or read book Field Monitoring of Scour Critical Bridges written by Xiong Yu and published by . This book was released on 2010 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
