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Safi, Mohammed. "LCC Applications for Bridges and Integration with BMS." Licentiate thesis, KTH, Bro- och stålbyggnad, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90342.
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Bridges are vital links in many transport networks and represent a big capital investment for both governments and taxpayers. They have to be managed in a way that ensures society's needs are optimally met. In many countries, bridges are mainly managed using bridge management systems (BMSs). Although many BMSs contain some forms of life-cycle costing (LCC), the use of LCC in bridge engineering is scarce. LCC in many BMSs has mainly been applied within the bridge operation phase, even though it has several useful applications within the bridge entire life, from cradle to grave. This licentiate thesis discusses the need of a BMS with integrated comprehensive LCC tools that can assist decision-makers at all levels and within all phases in selecting the most cost-effective alternative from an array of applicable alternatives. The thesis introduces the Swedish Bridge and Tunnel Management System (BaTMan). Acomprehensive integrated LCC implementation scheme is illustrated, taking into account the bridge investment and management process in Sweden. The basic LCC analytical tools as well as other helpful LCC techniques are addressed. Detailed case studies for real bridges at different investment phases are presented to demonstrate the recent improvement of BaTMan practically in the LCC integration. Cost records for 2,508 bridges extracted from BaTMan inventory data are used as input data in the presented case studies. Considering the same records, the average real and anticipated initial costs of different bridge types in Sweden will schematically be presented. The thesis introduces a bridge LCC program developed over this research named "BaTMan-LCC". The reason for which this program was developed is to combine all possible LCC applications for bridges in one tool and facilitate its implementation. The sensitivity analysis as well as the LCC saving potential highlighted in the presented case studies emphasizes the feasibility and the possibility of developing BaTMan to accommodate the applications of BaTMan-LCC.<br>QC 20120301<br>ETSI
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Wi, Huiju. "Evaluating Defects of Bridge Elements Using an Image Processing Approach." Thesis, Griffith University, 2014. http://hdl.handle.net/10072/366670.
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The total expenditure on bridge maintenance/rehabilitation and improvement for the year 2010-11 in Australia was AUD1.2 billion. This was a 67% rise in ten years. The efficient use of public funds for the structural integrity of bridge networks requires an effective bridge asset management technology. For effective asset management, many bridge authorities have implemented Bridge Information System (BIS) or Bridge Management System (BMS) to manage their routine inspection information. The success of a BMS is highly dependent on the quality of bridge inspection results and accurate estimation of future bridge condition ratings. To ensure such successful outcome, a BMS must (1) contains reliable, consistent and accurate condition data from routine bridge inspections; and (2) encompasses a reliable deterioration modelling that overcomes the shortcomings of lacking historical bridge inspection records. However, without consistent and accurate bridge condition data, reliable BMS outcomes would not be expected regardless of superiority of asset management techniques. Although current routine bridge inspections are required to be carried out by certified inspectors to provide condition assessment, several limitations have been identified as demonstrated in published literatures. They include: (1) visual inspections are subjective and not always reliable; (2) entire manual process is costly and time-consuming; (3) a number of safety risks are associated with filed inspectors; (4) inspection requires experienced and highly trained personnel – now most bridge authorities are facing the issue of shortage of required level of inspectors.<br>Thesis (Masters)<br>Master of Philosophy (MPhil)<br>Griffith School of Engineering<br>Science, Environment, Engineering and Technology<br>Full Text
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Lee, Jaeho. "A Methodology for Developing Bridge Condition Rating Models Based on Limited Inspection Records." Thesis, Griffith University, 2007. http://hdl.handle.net/10072/367207.
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Transportation infrastructure facilities are the essential components for the continuous development of the economic and community well-being of any country. Maintaining such facilities is a difficult task for service authorities and to keep their assets in optimal conditions at all times. To assist with conducting such a task, infrastructure management systems (IMSs) have been developed for effective asset management. The main function of these systems is to minimise total operation costs for service authorities while maximising the benefits for public users.
To obtain the right decisions from an IMS, software packages must have high quality asset information for the system’s various analytical processes. For an IMS to correctly predict a mixture of future maintenance and repair needs, periodic inspection records are the key resources amongst other information requirements. However, many infrastructure facilities were already in existence long before the IMS technology was developed. Thus, many years of past inspection records for those structures are always lacking. In particular, the lack of such historical records which are required as inputs to IMSs is a very common operational problem in their implementation. The present research was instigated by the prevailing lack of past inspection records available to service agencies for the effective use of IMSs.
Among IMSs, a bridge management system (BMS) has been selected for this thesis project to solve the abovementioned problem of historical data record gaps. Similar to IMS, BMS software packages also require various types of datasets to operate. One of the most significant BMS data requirements is the historical bridge element condition ratings forming part of the past bridge inspection records. In cases of insufficient or non-existent of such datasets, BMS software packages are unable to accurately predict future bridge status. This is because historical bridge condition rating data can affect approximately 60% of the BMS analysis modules.
In practice, the most common problem faced by most bridge management agencies during the early stages of BMS implementation arises from incongruence of those input information between the bridge agency’s existing bridge data and the input requirements of commercial BMS software packages. Although most bridge agencies in the past conducted inspections and maintenance, the format of such bridge inspection records is different from what are required for BMS implementations. These data incompatibilities are the major barriers to form a BMS database and consequently its implementation. This is achieved by utilising the existing incompatible and limited bridge inspection records to produce sufficient amounts of historical condition rating datasets for a BMS database.
The proposed condition rating model adopts an Artificial Neural Network (ANN) technique to back-predict the unavailable historical condition rating patterns using a limited amount of existing bridge condition ratings. The ANN-based bridge element condition rating models presented in this thesis are constructed utilising limited datasets, i.e. bridge inspection records, obtained from three different bridge agencies. This thesis report covers three key topics: feasibility study, refined methodology and case studies. The feasibility study given in Chapter 3 evaluates the condition rating prediction accuracy of an ANN technique to facilitate the identification of problems and limitations. The refined methodology given in Chapter 4 helps to enhance the ANN model to cater for the problems and limitations identified in the feasibility study, resulting in the Backward Prediction Model (BPM). The case studies presented in Chapter 5 are carried out to validate the Backward Prediction Model.
The proposed BPM provides a holistic perspective of effective BMS implementations and operations and offers significant contributions to solving the current BMS operational problems on the lacking of past inspection records.
For ease of reading and referencing, all figures, tables and acronyms are listed on pages xii, xvi and xviii respectively. The end of each chapter also provides a summary of relevant research outcomes.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Griffith School of Engineering<br>Science, Environment, Engineering and Technology<br>Full Text
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Lowry, Gordon Dennis. "User perceptions and the utilisation of building management systems." Thesis, Brunel University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311239.
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Wang, Lingchang XI. "Development of a Hardware-In-the-Loop Simulator for Battery Management Systems." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397656909.
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Zhang, Su. "Sensor data management in bridge health monitoring systems /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1068237721&sid=13&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Mohamed, Hosny Abbas Hosny Carleton University Dissertation Engineering Civil and Environmental. "Development of optimal strategies for Bridge Management Systems." Ottawa, 1995.
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Yue, Yanchao. "Impact of Seismic Vulnerability on Bridge Management Systems." Doctoral thesis, Università degli studi di Trento, 2011. https://hdl.handle.net/11572/368074.
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Motivated by the potential vulnerability of their road infrastructure, many national authorities and local Departments of Transportation are incorporating seismic risk assessment in their management systems. This Dissertation aims to develop methods and tools for seismic risk analysis that can be used in a Bridge Management System (BMS); helping bridge owners to assess the costs of repair, retrofit and replacement of the bridges under their responsibility.
More specifically, these tools are designed to offer estimates of:
(1) the seismic risk to single components of bridges and their expected performance after an earthquake.
(2) the impact a priori (i.e. before an earthquake) of a given earthquake on the operation of a road network, in terms of connectivity between different locations.
(3) the damage a posteriori (i.e. after an earthquake) to road network operation, based on prior knowledge of network vulnerability and on the observed damage to a small number of single bridges.
The effectiveness of these methods is tested and validated in a specific case study, the bridge stock of the Autonomous Province of Trento (APT) in Italy.
To address the first point, I will first introduce the fragility curve method for risk assessment of individual bridges. The Hazus model is chosen as the most appropriate and is applied to the bridges of the APT stock. Once the fragility curves for all the bridges have been generated, a risk analysis is performed for three earthquake scenarios (with return periods of 72, 475 and 2475 years) and four condition states (operational, damage, life safety and collapse limit state). Next, I will extend the results of the component level analysis to the network level: the APT road network is modeled in the form of a graph and the problem of connectivity between two locations is analyzed. A shortest path algorithm is introduced and implemented to identify the best path between any two given places. Correlation in capacity and demand among bridges is not considered at this stage.
After reiterating the fundamentals of probability theory, the theory of Bayesian Networks is introduced. The Bayesian Network approach is used to incorporate mutual correlation in capacity and demand, in risk assessment of a bridge stock. The concept is first formulated and illustrated on a simple case (the ‘twin bridge problem’), then extended to the general case of a full stock. I will show how the same framework can be used in post-earthquake assessment problems, where the evidence of the state of one or more bridges affects the prediction of the performance of another bridge. The outcomes and the limits of this work are discussed at the end of the Thesis.
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Yue, Yanchao. "Impact of Seismic Vulnerability on Bridge Management Systems." Doctoral thesis, University of Trento, 2011. http://eprints-phd.biblio.unitn.it/792/1/YUEthesis_final20120530.pdf.
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Motivated by the potential vulnerability of their road infrastructure, many national authorities and local Departments of Transportation are incorporating seismic risk assessment in their management systems. This Dissertation aims to develop methods and tools for seismic risk analysis that can be used in a Bridge Management System (BMS); helping bridge owners to assess the costs of repair, retrofit and replacement of the bridges under their responsibility.
More specifically, these tools are designed to offer estimates of:
(1) the seismic risk to single components of bridges and their expected performance after an earthquake.
(2) the impact a priori (i.e. before an earthquake) of a given earthquake on the operation of a road network, in terms of connectivity between different locations.
(3) the damage a posteriori (i.e. after an earthquake) to road network operation, based on prior knowledge of network vulnerability and on the observed damage to a small number of single bridges.
The effectiveness of these methods is tested and validated in a specific case study, the bridge stock of the Autonomous Province of Trento (APT) in Italy.
To address the first point, I will first introduce the fragility curve method for risk assessment of individual bridges. The Hazus model is chosen as the most appropriate and is applied to the bridges of the APT stock. Once the fragility curves for all the bridges have been generated, a risk analysis is performed for three earthquake scenarios (with return periods of 72, 475 and 2475 years) and four condition states (operational, damage, life safety and collapse limit state). Next, I will extend the results of the component level analysis to the network level: the APT road network is modeled in the form of a graph and the problem of connectivity between two locations is analyzed. A shortest path algorithm is introduced and implemented to identify the best path between any two given places. Correlation in capacity and demand among bridges is not considered at this stage.
After reiterating the fundamentals of probability theory, the theory of Bayesian Networks is introduced. The Bayesian Network approach is used to incorporate mutual correlation in capacity and demand, in risk assessment of a bridge stock. The concept is first formulated and illustrated on a simple case (the ‘twin bridge problem’), then extended to the general case of a full stock. I will show how the same framework can be used in post-earthquake assessment problems, where the evidence of the state of one or more bridges affects the prediction of the performance of another bridge. The outcomes and the limits of this work are discussed at the end of the Thesis.
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Frost, Damien. "Battery management systems with active loading and decentralised control." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:27c8947d-967c-476a-b778-a0ad4d0a5f48.
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This thesis presents novel battery pack designs and control methods to be used with battery packs enhanced with power electronics. There are two areas of focus: 1) intelligent battery packs that are constructed out of many hot swappable modules and 2) smart cells that form the foundation of a completely decentralised battery management system (BMS). In both areas, the concept of active loading/charging is introduced. Active loading/charging balances the cells in a battery pack by loading each cell in proportion to its capacity. In this way, the state of charge of all cells in a series string remain synchronized at all times and all of the energy storage potential from every cell is utilized, despite any differences in capacity there may be. Experimental results from the intelligent battery show how the capacity of a pack of variably degraded cells can be increased by 46% from 97 Wh to 142 Wh using active loading/charging. Engineering design challenges of building a practical intelligent battery pack are addressed. Start up and shut down procedures, and their respective circuits, were carefully designed to ensure zero current draw from the battery cells in the off state, yet also provide a simple mechanism for turning on. Intra-pack communication was designed to provide adequate information flow and precise control. Thus, two intra-pack networks were designed: a real time communication network, and a data communication network. The decentralised control algorithms of the smart cell use a small filtering inductor as a multi-purpose sensor. By analysing the voltage across this filtering inductor, the switching actions of a string of smart cells can be optimised. Experimental results show that the optimised switching actions reduce the output voltage ripple by 83% and they synchronize the terminal voltages of the smart cells, and by extension, their states of charge. This forms the basis of a decentralised BMS that does not require any communication between cells or with a centralised controller, but can still achieve cell balancing through active loading/charging.
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Kim, Wonkyu. "A systems approach to transportation infrastructure management : development of a Highway Management System for the Virginia DOT /." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-06062008-160648/.
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Chowdhury, S. M. Sifat Morshed. "Adaptive Cell Balancing for Modular Battery Management Systems." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1589392523754789.
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Svensson, Henrik. "Pre-Study for a Battery Storage for a Kinetic Energy Storage System." Thesis, Uppsala universitet, Elektricitetslära, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-249173.
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This bachelor thesis investigates what kind of battery system that is suitable for an electric driveline equipped with a mechanical fly wheel, focusing on a battery with high specific energy capacity. Basic battery theory such as the principle of an electrochemical cell, limitations and C-rate is explained as well as the different major battery systems that are available. Primary and secondary cells are discussed, including the major secondary chemistries such as lead acid, nickel cadmium (NiCd), nickel metal hydride (NiMH) and lithium ion (Li-ion). The different types of Li-ion chemistries are investigated, explained and compared against each other as well as other battery technologies. The need for more complex protection circuitry for Li-ion batteries is included in the comparison. Request for quotations are made to battery system manufacturers and evaluated. The result of the research is that the Li-ion NMC energy cell is the best alternative, even if the cost per cell is the most expensive compared to other major technologies. Due to the budget, the LiFeMnPO4 chemistry is used in the realisation of the final system, which is scaled down with consideration to the power requirement.
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Cheng, Yousheng. "Development of bridge management systems using fuzzy case-based reasoning /." Search for this dissertation online, 2005. http://wwwlib.umi.com/cr/ksu/main.
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Khakbaz, Gelareh. "Integrated water systems of The Grove Library: Optimisation via data analysis from an Automated Building Management System (BMS)." Thesis, Khakbaz, Gelareh (2013) Integrated water systems of The Grove Library: Optimisation via data analysis from an Automated Building Management System (BMS). Other thesis, Murdoch University, 2013. https://researchrepository.murdoch.edu.au/id/eprint/16949/.
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This study is an attempt to uncover the underlying operation and maintenance issues in sustaining the operation of an automated green building with focus on its water systems. The Grove Library is a public building in Peppermint Grove, Western Australia, with smart design aimed to address environmentally sustainable concepts in their entirety.
A sophisticated Building Management System (BMS) integrates the operation of the entire Environmentally Sustainable Design (ESD) systems in operation at The Grove. However a number of continual breakdowns in the operation of the ESD water systems, namely wastewater, rainwater and irrigation systems, lead to high levels of disappointment for the people managing and operating these systems. This is the first time that data have been extracted from the BMS. Prior to this study, it was possible to quantify the performance of any of the ESD water systems. This has resulted in the inability of external contractors to monitor the ESD systems’ operation.
This study discussed the factors contributing to this situation using data analysis as the main method for troubleshooting and investigating the causes to these breakdowns. Upon achieving a good understanding of the situation, the recommendations were able to be formulated.
It was found that the current situation with the ESD water systems at The Grove is a consequence of some interrelated factors forming a ‘vicious circle’. The ESD systems, their maintenance, the BMS and the management were the key factors identified as responsible for the issues in The Grove. The recommendations produced in this study were mainly on the technical side of the problem, that is, the BMS, ESD water systems and their maintenance. In order to overcome the issues at The Grove this relationship among these factors should be recognised and established.
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Malachowska, Julia, and Miko Nore. "Emulation of Analog Front-End isoSPI communication for Battery Management Systems." Thesis, KTH, Mekatronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297789.
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This study aims to investigate how an emulator could be developed as a testing tool for Battery Management Systems (BMS) by emulating the Analog Frontend (AFE) circuit communicating with a control unit for monitoring of LithiumIon Batteries. All of the research was conducted in the context of the company Northvolt. By analysing data collected through a questionnaire, it was evident that an emulator testing tool could potentially make the BMS development process significantly more efficient. A demonstrator was developed as a part of the study. It fulfilled almost all of the requirements initially stated, but required the control unit to send commands in a fixed sequence, which the current BMS control unit did not. A fixed sequence would however enable the incorporation of the developed emulator, as well as introducing other advantages such as predictability. The study showed that the most important factor to consider for developing an AFE communication emulator for BMS testing was robustness and repeatability of the timings of the communication signals.<br>Syftet med denna studie var att undersöka hur ett testverktyg baserat på en emulator skulle kunna utvecklas för batteristyrsystem. Studien genomfördes på batteriföretaget Northvolt. Genom att analysera data insamlad via ett frågeformulär framgick det tydligt att ett testverktyg baserat på en emulator hade god potential att göra utvecklingsprocessen av batteristyrsystem mer effektiv. En prototyp utvecklades som en del av studien. Denna uppfyllde nästan alla de initialt uppsatta kraven, men var anpassad för kommunikation i en fix sekvens, till skillnad från det aktuella systemet hos företaget. Via studien fann man att implementationen av en fix kommunikationssekvens skulle medföra önskvärda egenskaper hos systemet såsom förutsägbarhet. Vidare visade studien att den viktigaste faktorn att ta i beaktning för utveckling av en emulator var robusthet och repeterbarhet hos timingen av kommunikationssignalerna. Detta eftersom kommunkationen mellan enheter förlitar sig på korrekt timing av varje skickad bit för korrekt inlästa meddelanden.
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Zhang, Yizhou. "Modularized Battery Management Systems for Lithium-Ion Battery Packs in EVs." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194316.
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The (Battery management system)BMS has the task of ensuring that for the individual bat-tery cell parameters such as the allowed operating voltage window or the allowable temperature range are not violated. Since the battery itself is a highly distinct nonlinear electrochemical de-vice it is hard to detect its internal characteristics directly. The requirement of predicting battery packs’ present operating condition will become one of the most important task for the BMS. Therefore, special algorithms for battery monitoring are required.In this thesis, a model based battery state estimation technique using an adaptive filter tech-nology is investigated. Different battery models are studied in terms of complexity and accuracy. Following up with the introduction of different adaptive filter technology, the implementation of these methods into battery management system is decribed. Evaluations on different estimation methods are implemented from the point of view of the dynamic performance, the requirement on the computing power and the accuracy of the estimation. Real test drive data will be used as a reference to compare the result with the estimation value. Characteristics of different moni-toring methods and models are reported in this work. Finally, the trade-offs between different monitor’s performance and their computational complexity are analyzed.<br>BMS (eng. battery management system) har till uppgift att se till att viktiga parametrar såsom tillspännings- och temperaturintervall upprätthålls för varje individuell battericell. Då en battericells beteende är ickelinjärt är det svårt att bestämma cellens interna karakteristika direkt. Att kunna förutsäga dessa karakteristika för ett komplett batteripack kommer att en mycket viktig funktion hos framtida BMS. I detta examensarbete har en modellbaserad tillståndsestimeringsmetod med användande av adaptiv filtrering undersökts. Olika batterimodeller har studerats med avseende på komplexitet och noggrannhet. Efter introduktionen av olika metoder för adaptiv filtrering har dessa metoder implementerats i en BMS modell. Utvärdering av de olika metoderna för att åstadkomma tillståndsestimering har sedan utförts med avseende på dynamisk prestanda, krav på beräkningskraft och noggrannhet hos de resulterande estimaten. Data från uppmätta kördata från ett fordon har använts som referens för att jämföra de olika estimaten. Slutligen presenteras en jämförelse mellan de olika tillståndsestimeringsmetodernas prestanda när de appliceras på de olika batterimodellerna.
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MALACHOWSKA, JULIA, and MIKO NORE. "Emulation of Analog Front-End isoSPI communication for Battery Management Systems." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299264.
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This study aims to investigate how an emulator could be developed as a testing tool for Battery Management Systems (BMS) by emulating the Analog Front-end (AFE) circuitcommunicating with a control unit for monitoring of Lithium-Ion Batteries. All of the research was conducted in the context of the company Northvolt. By analysing data collected through a questionnaire, it was evident that an emulator testing tool could potentially make the BMS development process significantly more efficient. A demonstrator was developed as a part of the study. It fulfilled almost all of the requirements initially stated, but required the control unit to send commands in a fixed sequence, which the current BMS control unit did not. A fixed sequence would however enable the incorporation of the developed emulator, as well as introducing other advantages such as predictability. The study showed that the most important factor to consider for developing an AFE communication emulator for BMS testing was robustness and repeatability of the timings of the communication signals.<br>Syftet med denna studie var att undersöka hur ett testverktyg baserat på en emulator skulle kunna utvecklas för batteristyrsystem. Studien genomfördes på batteriföretaget Northvolt. Genom att analysera data insamlad via ett frågeformulär framgick det tydligt att ett testverktyg baserat på en emulator hade god potential att göra utvecklingsprocessen av batteristyrsystem mer effektiv. En prototyp utvecklades som en del av studien. Denna uppfyllde nästan alla de initialt uppsatta kraven, men var anpassad för kommunikation i en fix sekvens, till skillnad från det aktuella systemet hos företaget. Via studien fann man att implementationen av en fix kommunikationssekvens skulle medföra önskvärda egenskaper hos systemet såsom förutsägbarhet. Vidare visade studien att den viktigaste faktorn att ta i beaktning för utveckling av en emulator var robusthet och repeterbarhet hos timingen av kommunikationssignalerna. Detta eftersom kommunkationen mellan enheter förlitar sig på korrekt timing av varje skickad bit för korrekt inlästa meddelanden.
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O'Har, John Patrick. "Transportation asset management systems: a risk-oriented decision making approach to bridge investment." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41231.
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Transportation Asset Management (TAM) systems are in use at a significant number of transportation agencies. These systems can be used to effectively allocate resources and continuously inventory and monitor the condition of transportation infrastructure assets. Risk-oriented decision making is becoming an increasingly important component of the management process at many organizations, including transportation agencies. TAM systems can be used to incorporate risk assessment and risk management techniques at transportation agencies.
To demonstrate the value of incorporating risk in TAM systems, an examination of the literature was performed, and a case study was conducted. This case study incorporated risk in bridge project prioritization through the utilization of data from the National Bridge Inventory (NBI), and application of Multi Attribute Decision Making (MADM) concepts to address uncertainty and prioritize selected bridges in the state of Georgia.
The case study examines the impacts of data aggregation and disaggregation, and the incorporation of uncertainty on bridge project prioritization. Results of this analysis show that when available, disaggregate data on bridge condition should be used. In addition, uncertainty, in terms of performance risk, should be incorporated when past bridge condition data is available. Furthermore, decision-maker input is an important component of the Multi Attribute Utility Theory (MAUT) prioritization methodology used in this analysis. Decision-makers determine the relative importance of certain attributes, which is one of the strengths of this type of prioritization effort.
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Mak, Yet Feng. "Conditions for natural gas to become an effective bridge fuel to a low-carbon future." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/107607.
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Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, School of Engineering, System Design and Management Program, Engineering and Management Program, February 2016.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 78-84).<br>Natural gas has commonly been described as a 'bridge fuel' that could transition U.S. from fossil fuels to a low-carbon energy system by 2050 in order to reach the internationally agreed target of limiting the global mean surface temperature to about 2 degrees Celsius (°C) above pre-industrial levels. This natural gas resource has grown tremendously over the last decade, as its production has been fueled by the use of more advanced hydraulic fracturing and horizontal drilling technologies. Being a cleaner form of fossil fuel, burning natural gas emits about half as much carbon dioxide as coal and is thought to aid in decarbonizing the nation by displacing coal as a fuel for power generation. However, the increased supply of cheap natural gas could also have an effect of delaying the advancement of renewable resources such as solar and wind. Nonetheless, optimal conditions could be explored on how natural gas can become an effective 'bridge fuel' towards a low carbon energy system. This thesis developed a system dynamics model to analyze these required conditions and found that high natural prices that rise to $26.45/mmBTU in 2050 are necessary to hit the 2°C target. An efficient policy that could drive these high natural gas prices is the carbon tax. Furthermore, another important role that natural gas serves is as a backup power source for intermittent renewable energy resources.<br>by Yet Feng Mak.<br>S.M. in Engineering and Management
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Son, Jungbaeg. "Development of Reliable Long-term Bridge Deterioration Model using Neural Network Techniques." Thesis, Griffith University, 2010. http://hdl.handle.net/10072/367833.
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Bridges are vital components of any road network which demand crucial and timely decision-making for Maintenance, Repair and Rehabilitation (MR&R) activities. Bridge Management Systems (BMSs) as a Decision Support System (DSS), have been developed since the early 1990’s to assist in the management of a large bridge network.
Historical condition ratings obtained from biennial bridge inspections are major resources for predicting future bridge deteriorations via BMSs. Available historical condition ratings in most bridge agencies, however, are very limited, and thus posing a major barrier for predicting reliable future structural performance.
To alleviate this problem, a Backward Prediction Model (BPM) technique has been developed and verified to help generate missing historical condition ratings. This is achieved through establishing a correlation between the known condition ratings and such non-bridge factors as climate and environmental conditions, traffic volumes and population growth. Such correlations can then be used to obtain the bridge condition ratings of the missing years. 21 non-bridge factors which were used in initial BPM methodology are refined to 6 non-bridge factors because BPM- generated historical condition rating using this 6 non-bridge factors show good trend with existing condition ratings.
With the help of generated datasets, the currently available bridge deterioration model can be utilised to more reliably forecast future bridge conditions. The prediction accuracies based on 4 and 9 BPM-generated historical condition ratings are compared, using deterministic and stochastic bridge deterioration models. The comparison outcomes indicate that the prediction error decreases as more historical condition ratings become available. This implies that the BPM can be utilised to generate unavailable historical data, which is crucial for bridge deterioration models to achieve more accurate prediction results. Nevertheless, there are still considerable limitations in the existing bridge deterioration models.
In view of this, feasibility study on Time Delay Neural Network (TDNN) using BPM-generated historical condition ratings is conducted as an alternative to existing bridge deterioration models. The proposed TDNN model is capable of solving a number of problems encountered in the existing bridge deterioration models. Thus, it is anticipated that the TDNN using BPM-generated data can lead to further improvement of the current BMS outcome.<br>Thesis (Masters)<br>Master of Philosophy (MPhil)<br>Griffith School of Engineering<br>Science, Environment, Engineering and Technology<br>Full Text
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Pinto, da Silva Filho Luiz Carlos. "Towards advanced bridge management systems : investigation of the possibility of developing an improved appraisal model based on a novel system architecture." Thesis, University of Leeds, 1999. http://etheses.whiterose.ac.uk/12293/.
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Bridge Management Systems have been an emergent area of research in this decade. This has been fostered by the recognition of the need for computer support in the decision making process involved in defining maintenance and improvement strategies to networks of bridges. While existing systems have already prove their worthiness, there are still far from satisfying entirely the complex and evolving user needs. Changing society perceptions are introducing new requirements and demanding the consideration of issues like environmental quality and congestion minimisation. At the same time, IT developments are opening various new alternatives to the problem of creating flexible, user-friendly and easily maintainable systems. Given this panorama, this study investigates the possibility of developing more advanced Bridge Management Systems that could lead to a more open, integrated and socially aware approach to Bridge Management. It proposes the adoption of a new appraisal model based on a wider consideration of maintenance and deterioration consequences and an innovative view of bridge utility as a measure of benefits. An innovative system architecture is used to support the model based on three main elements: object orientation, geo-referencing and soft reasoning. The results obtained indicate that the use of this new approach can significantly alter the allocation of the budget. The conclusion of the work is that it is possible to develop more advanced systems and that the adoption of the framework proposed can have a significant impact on Bridge Management decision-making. Further researches will be necessary to refine the model and investigate how to develop other components of an ABMS. The flexibility of the system architecture proposed is an important advantage in this sense because it allows a progressive and steady advance, with the results of new researches being gradually and seamlessly incorporated.
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Callow, Daniel John. "Optimisation of the Neural Network Process for an Improved Bridge Deterioration Model." Thesis, Griffith University, 2015. http://hdl.handle.net/10072/367038.
Full textAbstract:
Infrastructure maintenance is a vital aspect for any country to ensure safety and reliability of its infrastructure and the population which use these assets. To ensure that the highest degree of maintenance is performed and recorded for infrastructure, Bridge Management Systems (BMSs) have been developed to allow bridge agencies to have an effective means to determine and understand the best decisions to make for infrastructure maintenance.
Various models have been developed for the BMS with the most typical approach being the stochastic Markovian-based method, using currently retrieved bridge data as inputs for predicting the bridges’ future deterioration levels. However, a drawback to this method is the disregard for historical data as references to future predictions. This situation has led to the advancement of BMSs to incorporate Artificial Neural Network (ANN) processes as a means of predicting future bridge deterioration levels.
This advancement in ANN-based BMSs is an improvement over the typical model due to the incorporation of historical data curves. However, a drawback to this is the fact that biannual bridge inspection data has only started to be collected within the past 10-20 years, limiting the inputs for ANN methods. Further research into ANN models has developed a means of deriving the missing historical data through the use of current bridge inspection data and non-bridge data collected from various sources. This method is referred to as the Backwards-Prediction Model (BPM) and is an effective method for determining this missing historical data for subsequent use as inputs to further ANN methods for future prediction.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Information and Communication Technology<br>Science, Environment, Engineering and Technology<br>Full Text
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Sapienza, Paola. "Un sistema di supporto alle decisioni per la gestione della manutenzione dei ponti di una rete viaria." Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/1010.
Full textAbstract:
I sistemi di gestione dei ponti sono essenziali per l'ottimizzazione delle risorse disponibili. La priorità delle attività manutentive e la valutazione delle diverse strategie di manutenzione sono solitamente basate sulla definizione di indici di condizione. Nel presente tesi viene sviluppato un sistema di supporto alle decisioni per la manutenzione dei ponti a livello di rete, basato sulla teoria del Dominance-based Rough Set Approach (DRSA). Il DRSA produce un modello decisionale espresso in termini di regole facilmente comprensibili "se...allora..."che controllano il processo decisionale ed evitano l'effetto "scatola nera" di altri sistemi alternativi.
Nel sistema di supporto decisionale proposto, i ponti sono descritti da una serie di 16 criteri relativi allo stato di degrado del ponte, alle caratteristiche della struttura, del territorio,del traffico e della rete. Per illustrare il sistema è stato proposto un caso di studio che coinvolge alcuni ponti sulle strade italiane. Il metodo proposto è uno strumento flessibile, i cui parametri possono essere periodicamente aggiornati in conseguenza delle politiche dell'ente gestore e della pratica acquisita.
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Florêncio, Cláudia. "Learning to bridge conservation and development: A case study of the Environmental Monitors Programme in Kruger to Canyons Biosphere Reserve." Thesis, Stockholms universitet, Stockholm Resilience Centre, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-131843.
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We live in a world that faces several social and environmental problems and achieving sustainable development in contexts where it is necessary to alleviate poverty without eroding the capacity of the ecosystems to support future generations is challenging. Therefore, fostering sustainable development requires enabling both society and environment to cope with disturbances, adapt to and shape change (resilience). Literature suggests that adaptive co-management practices are appropriate for building resilience and fostering sustainable development. Additionally, studies have highlighted the role of bridging organizations in coordinating and facilitating adaptive co-management. However, adaptive co-management has not been studied in poverty contexts. This thesis aims to understand what the main tasks of bridging organizations are, and how they facilitate and stimulate adaptive co-management in poverty contexts and their role in nurturing sustainability. The Environmental Monitors Programme of the Kruger to Canyons Biosphere Reserve was chosen as a case-study. Biosphere reserves are considered learning sites for sustainable development. The programme was studied through the lenses of a bridging organization. Semi-structured interviews and participatory observation with stakeholders identified: 1) the importance of existing networks and collaborations; 2) monitoring contribution to the identification of social and environmental issues, experimentation contribution to the implementation of sustainable harvesting practices; 3) environmental education combined with social learning lead to community empowerment and adaptive responses that e.g. address erosion; 4) environmental monitors have a crucial role in linking organizations and communities; 5) challenges related to low income settings include communities’ basic needs. This study illustrates the need to address both social and ecological problems in a concerted manner, by capacitating and empowering communities while conserving the environment. Additionally, points out the need of studying alternative co-management strategies that give focus on different priorities regarding stakeholders’ interests and the influence of power in decision-making in poverty contexts.
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Björkdahl, Elin, and Julia Stadler. "INTERNET OF THINGS INOM DRIFT OCH UNDERHÅLL I FÖRVALTNINGSSKEDET." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Byggnadsteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-36445.
Full textAbstract:
Abstract Purpose: This work presents Internet of Things or IoT in facility management; operation and maintenance. One of the many functions of IoT is making “smart” building components, which can communicate when they break and can be controlled from a distance. Today there are many articles on how you can use IoT in buildings but not as many on how you can use it in operation and maintenance of real estates. Therefore, the aim of this thesis is to investigate the possibilities of IoT in facility management; operation and maintenance work. This is investigated by the questions: (1) How can IoT be used in the facility management; operation andmaintenance work? (2) What are the savings in terms of workhours that can be made by using IoT in facility management; operation and maintenance work? (3) What is the attitude to IoT in the facility management industry? Method: The main strategy for this thesis is a case study in the facility section of the municipality in Jönköping. Approaches include interviews with IoT-consultants and employers at the facility section, document analysis of the workhours for different tasks of a operation technician and a literature study. Findings: The first question is answered by that IoT can be used for almost everything because of the huge amount of sensor types and that new ones are constantly in the making. You can also make unique IoT systems which contributes to the flexibility.The limits today are costs and finding value in the collected data. The second question is answered by that saving possibilities exists. Calculations are made based on attitudes from respondents and what they think are possible savings.This results in savings of about 13 000 workhours/year out of 30 000 workhours/year which equals 40 %. The third question is answered by that both employers at the facility section and IoT-consultants find IoT in facility management interesting. Of the different work-categories, it is interesting to mention that the most positive are the real estate managers and the maintenance engineers and the least positive are the operation technicians. Implications: Conclusions made are that the possibilities of IoT in facility management; operation and maintenance are many. In the future, a lot of savings of workhours can be made by using IoT. Since interest in IoT exists at the facility-section future studies should explore the costs of different IoT-systems. If the municipality of Jönköping chooses to implement IoT in their facilities they can become a role model for other facility managers. Limitations: The limitations in this work are the different costs of IoT-products and how the IoT-systems are built. The work tasks investigated include only supervision-tasks.<br>Sammanfattning Syfte: Detta arbete behandlar Internet of Things eller IoT inom drift och underhåll i förvaltningsskedet. IoT handlar bl.a. om “smarta” byggnadskomponenter som kan meddela när de går sönder samt att man kan styra dessa på avstånd. Det finns många tidigare undersökningar kring hur man kan använda IoT i byggnader men inte särskilt många undersökningar på hur detta kan användas inom just drift och underhållsarbetet med fastigheter. Därför är målet med detta arbete att utreda möjligheterna till användning av Internet of Things inom drift och underhåll i förvaltningsskedet. Som i sin tur bryts ner i frågeställningarna: (1) Vilka användningsområden finns det för Internet of Things inom fastighetsförvaltning, avseende drift och underhåll? (2) Vilka besparingar i form av arbetstid skulle man kunna åstadkomma genom att tillämpa Internet of Things inom fastighetsförvaltning, avseende drift och underhåll? (3) Hur ser inställningen ut för tillämpning av Internet of Things i förvaltningsbranschen? Metod: Huvudstrategin för detta arbete är en Fallstudie på Fastighetsavdelningen, Jönköpings kommun. Tillvägagångssättet består av intervjuer med IoT-konsulter och med anställda på fastighetsavdelningen, dokumentanalys av enhetstider för olika arbetsuppgifter för drifttekniker i Jönköpings kommun samt litteraturstudie. Resultat: Den första frågeställningen besvaras att det mesta är möjligt med IoT då det finns en enorm mängd olika sensorer och det produceras ständigt nya sensortyper. Man kan även skräddarsy IoT-lösningar vilket bidrar till flexibiliteten i systemen. Det som sätter gränser för IoT i dagsläget är ekonomin samt att hitta värde i insamlade data. Frågeställning två visar att besparingsmöjligheter finns. Beräkningar är baserade på attityder hos respondenterna och vad de anser är rimliga besparingspotential. Detta resulterar i en besparing på ca 13 000 arbetstimmar/år av 30 000 arbetstimmar/år vilket är lika med 40 %. Den tredje frågeställningen ger resultatet att inställningen för att implementera IoT till arbetsuppgifter är överlag positiv hos både anställda på fastighetsavdelningen och IoT-konsulter. Av de olika yrkeskategorierna är det intressant att nämna att störst intresse ligger hos förvaltare och underhållsingenjörer och minst hos drifttekniker. Konsekvenser: Slutsatser dras att IoT kan effektivisera arbetet med drift och underhåll i förvaltningsskedet. Man kan komma att spara in mycket arbetstid genom att använda IoT. Eftersom intresse finns hos avdelningen borde man undersöka vidare vilka kostnader systemet kan komma att kosta om man skulle börja utrusta fastigheterna med sensorer etc. Vid en eventuell implementering kan Jönköpings kommun bli en förebild för andra förvaltare och hamna i framkant i teknikutvecklingen. Begränsningar: Avgränsningarna i detta arbete är kostnader för IoT-produkter och hur systemen i detalj är uppbyggda. De arbetsuppgifter som undersöks i detta arbete är tillsynsuppgifter.
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Bottazzi, Maurizio. "Strumenti per la valutazione dello stato conservativo e per la manutenzione programmata dei ponti della Provincia di Bologna." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amslaurea.unibo.it/102/.
Full textAbstract:
La tesi tratta di strumenti finalizzati alla valutazione dello stato conservativo e di supporto all'attività di manutenzione dei ponti, dai più generali Bridge Management Systems ai Sistemi di Valutazione Numerica della Condizione strutturale. Viene proposto uno strumento originale con cui classificare i ponti attraverso un Indice di Valutazione Complessiva e grazie ad esso stabilire le priorità d'intervento. Si tara lo strumento sul caso pratico di alcuni ponti della Provincia di Bologna. Su un ponte in particolare viene realizzato un approfondimento specifico sulla determinazione approssimata dei periodi propri delle strutture da ponte. Si effettua un confronto dei risultati di alcune modellazioni semplificate in riferimento a modellazioni dettagliate e risultati sperimentali.
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Bakhtiari, Hossein. "Evaluation of Thermal Comfort and Night Ventilation in a Historic Office Building in Nordic Climate." Licentiate thesis, Högskolan i Gävle, Energisystem och byggnadsteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-33941.
Full textAbstract:
Envelopes with low thermal performance are common characteristics in European historic buildings resulting in insufficient thermal comfort and higher energy use compared to modern buildings. There are different types of applications for the European historic buildings such as historic churches, historic museums, historic theatres, etc. In historic buildings refurbished to offices, it is vital to improve thermal comfort for the staff. Improving thermal comfort should not increase, preferably reduce, energy use in the building. The overall aim in this research is to explore how to improve thermal comfort in historic buildings without increasing, preferably reducing, energy use with the application of non-intrusive methods. This is done in form of a case study in Sweden. Thermal comfort issues in the case study building are determined through a field study. The methods include field measurements with thermal comfort equipment, data logging on BMS, and evaluating the occupant’s perception of a summer and a winter period indoor environment using a standardized questionnaire. According to questionnaire and thermal comfort measurements results, it is revealed that the summer period has the most dissatisfied occupants, while winter thermal comfort is satisfactory – but not exceptionally good. Accordingly, natural heat sinks could be used in form of NV, as a non/intrusive method, in order to improve thermal comfort in the building. For the historic building equipped with mechanical ventilation, NV strategy has the potential to both improve thermal comfort and reduce the total electricity use for cooling (i.e. electricity use in the cooling machine + the electricity use in the ventilation unit’s fans). It could decrease the percentage of exceedance hours in offices by up to 33% and reduce the total electricity use for cooling by up to 40%. The optimal (maximum) NV rate (i.e. the potential of NV strategy) is dependent on the thermal mass capacity of the building, the available NV cooling potential (dependent on the ambient air temperature), COP value of the cooling machine, the SFP model of the fans (low SFP value for high NV rate is optimal), and the offices’ door scheme (open or closed doors).
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Marques, José Miguel Branco. "Battery Management Systems (BMS) for Lithium-Ion Batteries." Master's thesis, 2014. http://hdl.handle.net/10316/39038.
Full textAbstract:
Dissertação de Mestrado em Energia para a Sustentabilidade apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra<br>O desenvolvimento de Veículos Eléctricos (EV) é na actualidade alvo dos fabricantes de
automóveis e pode ser considerado como uma solução imediata para um sistema de transporte
rodoviário sustentável, pela sua contribuição na redução da emissão de gases geradores do efeito
de estufa.
Os EVs têm como componente principal o sistema de armazenamento de energia. Este
sistema envolve para além da bateria, todos os sistemas de gestão e monitorização da mesma,
vulgarmente denominados pela sigla BMS do termo inglês “Battery Management System”. As
baterias usadas em EVs têm exigências elevadas em termos de segurança, densidade de potência (aceleração), densidade de energia (autonomia), elevada eficiência, ciclos de descarga
profundos e reduzidas taxas de auto-descarga entre outras. De entre as várias composições
químicas disponíveis para a construção de baterias, as baseadas em Lítio-Ferro-Fosfato (LiFePO4), Lítio-Itrio-Ferro-Fosfato (LiYFePO4) ou Lítio-Manganésio (LiMn2O4) são as mais
seguras e duradouras e como tal são estudadas no ISR-UC.
Os sistemas de gestão e monitorização de energia dedicados a EVs utilizam métodos de
estimação do estado de carga proprietários, não permitindo a sua utilização de forma simples
nem a sua melhoria. Por este motivo foi desenvolvido no ISR uma nova solução aberta e flexível
que permite estudar novos algoritmos de estimação do estado de carga.
Durante esta dissertação, instalou-se e testou-se um BMS comercial na bateria de Iões de
Lítio que alimenta uma das plataformas disponíveis no ISR-UC, o ISRobotCar. Uma segunda
plataforma, que foi re-instrumentada no decorrer deste projecto, também necessitou de substituição das suas baterias de chumbo originais por se encontrarem em fim de vida.
Devido às limitações encontradas em BMSs comerciais, desenvolveu-se de raiz um novo BMS,
designado nesta dissertação por ISR-BMS, que instrumenta uma nova bateria de LiYFePO4.
O estado de carga das baterias é uma informação fundamental para os utilizadores de
EVs. No entanto o estado de carga não é uma grandeza mensurável e apresenta uma grande
dependência da temperatura e das condições de operação da bateria. Existem várias técnicas
utilizadas para a estimação do estado de carga, que requerem a utilização de modelos das células
com diferentes complexidades. Para o ISR-BMS adoptou-se o modelo do circuito eléctrico
equivalente e modelizou-se uma célula de Iões de Lítio de 90Ah, baseado em testes laboratoriais
a diferentes temperaturas e ciclos de descarga.
Após a instalação do ISR-BMS na plataforma, efectuaram-se testes de condução real com
vista à validação das medições efectuadas e recolhidas do ISR-BMS.<br>The Electric Vehicle (EV) is already on the roadmap of every important car manufacturer
and is seen as the solution to a more sustainable transport system, contributing to a reduction
of the Greenhouse Gas Emissions.
The Energy Storage System (ESS) is a key component for EVs. This includes the battery and all the management and monitoring systems that compose the Battery Management
System (BMS). Those batteries have very demanding requirements regarding safety, power
density (acceleration), energy density (autonomy), high efficiency, deep discharge cycles or
low self-discharge rates to name a few. From the available chemistries for the construction of
EV batteries the Lithium-Iron-Phosphate (LiFePO4), Lithium-Yttrium-Iron-Phosphate (LiYFePO4) or Lithium-Manganate (LiMn2O4) are the most safe and long lasting and because of
that they are studied at the ISR-UC.
The energy monitoring and management systems for EVs use proprietary State of Charge
(SOC) algorithms that do not allow their easy use or improvement. For this reason was developed at the ISR-UC a new BMS with an open and flexible architecture allowing the implementation of new SOC estimation algorithms, the ISR-BMS.
During this dissertation, a commercial BMS was installed and tested on a Lithium-Ion
battery pack that powers one of the electric platforms available at the ISR-UC. A new platform
was completely re-instrumented during the course of this project and required a new ESS to
replace their original lead acid batteries, which became end of life.
The SOC of the battery is a vital information to the EV user. It can be displayed as the
percentage of full charge capacity that is still available from the battery or be used to estimate
the vehicle range based on additional information from previous driving cycles. However, it can
not be measured directly from the battery and have a strong dependence with the temperature
and the operating conditions.
Several SOC estimation techniques are mentioned on the literature, that require cell models
with different complexity and computer process requirements. In this work an Equivalent Electrical Circuit (EEC) model was adopted, with its parameters estimated based on experimental
data collected through cell testing at different temperatures and charge/discharge current profiles.
After installation of the ISR-BMS on the platform, on-road drive tests were performed to
acquire relevant information and validate the accuracy of collected measurements.
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CHAN, Chi-Chang, and 詹麒璋. "A Study on the Different Management Levels of Bridge Management Systems." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/44400147711201123317.
Full textAbstract:
碩士<br>國立臺北科技大學<br>土木與防災技術研究所<br>88<br>Bridges are the most important components in the expansive transportation networks. However, most people pay attention to the new bridges construction in the past, and neglect the maintenance and management of existing bridges. Not until recently, after several bridges damage around the world that caused serious disaster and losses, did everybody begin to pay attention to the maintenance and management of existing bridges by regularly inspecting, assessing, repairing and/or strengthening them. Under such circumstances, the bridge management systems (BMS) were developed to help the government agencies to maintain the bridges in their districts.
Recently, many theories and computer systems of the bridge management systems were developed. The Ministry of Transportation and Communications (MOTC) is also going to develop a bridge management system in the Taiwan area. However, the development of the bridge management systems varies with the bridge types and management requirements of each maintenance level. This thesis introduces the structures of bridge management system for MOTC, central and district offices of the Highway and Freeway Bureaus. A data-transfer computer software was also developed to transfer and converge the bridge inventory and inspection data from the data-base of the Highway Bureau and the Taipei County to the data-base of MOTC as an example in this thesis.
Bridge management systems can be classified into two types: the project-level and the network-level. This thesis introduces a developed concept and prototype, project-level bridge management system that was developed by using image processing and database techniques. The achievement of this study can be applied to the planning, the developing procedures and the methods of bridge management systems for different management levels.
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(11178285), Jose Capa Salinas. "An Unmanned Aerial Systems Evaluation Chamber for Bridge Inspection." Thesis, 2021.
Find full textAbstract:
<p>Civil engineering structures must provide an adequate and safe performance during their time of service, and the owners of these structures must have a reliable inspection strategy to ensure time-dependent damage does not become excessive. Visual inspection is the first step in every structural inspection; however, many elements in the majority of structures are difficult to access and require specialized personal and equipment. In an attempt to reduce the risk of the inspector and the cost of additional equipment, the use of Unmanned Aircraft Systems (UAS) has been increasing in the last years. The absence of standards and regulations regarding the use of UAS in inspection of structures has allowed the market to widely advertise Unmanned Aerial Vehicles (UAV) without protocols or qualifications that prove their effectiveness, leaving the owners of the structures to solely rely on claims of the vendors before deciding which technology suits their particular inspection needs. Focusing primarily on bridge inspection, this research aimed to address the lack of performance-based evaluation and standards for UAS, developing a validation criterion to evaluate a given UAS based on a repeatable test that resembles typical conditions in a structure. </p><p><br></p><p>Current applications of UAS in inspection of structures along with its advantages and limitations were studied to determine the current status of UAS technologies. A maximum typical rotor-tip-to-rotor-tip distance of an UAV was determined based on typical UAVs used in bridge inspection, and two main parameters were found to be relevant when flying close to structures: proximity effects in the UAV and availability of visual line of sight. Distances where proximity effects are relevant were determined based on several field inspections and flights close to structures. In addition, the use of supplementary technologies such as Global Positioning System (GPS) and Inertial Measurement Units (IMU) was studied to understand their effect during inspection. </p><p><br></p><p>Following the analysis, the author introduces the idea of a series of obstacles and elements inside an enclosed space that resemble components of bridge structures to be inspected using UAVs, allowing repeatability of the test by controlling outside parameters such as lighting condition, wind, precipitation, temperature, and GPS signal. Using distances based on proximity effects, maximum typical rotor-tip-to-rotor-tip distance, and a gallery of bridges and situations when flying close to bridge structures, a final arrangement of elements is presented as the evaluation chamber. Components inside the evaluation chamber include both “real” steel and concrete specimens as well as those intended to simulate various geometric configurations on which other features are mounted. Pictures of damages of steel and concrete elements have been placed in the internal faces of the obstacles that can be assessed either in real-time flight or in post-processing work. A detailed comparison between the objectives of this research project and the results obtained by the evaluation chamber was performed using visual evaluation and resolution charts for the images obtained, the availability of visual line of sight during the test, and the absence of GPS signal.</p><p><br></p><p>From the comparison and analysis conducted and based on satisfactory flight results as images obtained during flights, the evaluation chamber is concluded to be a repeatable and reliable tool to apply to any UAS prior to inspect bridges and other structures, and the author recommends to refrain from conducting an inspection if the UAS does not comply with the minimum requirements presented in this research work. Additionally, this research provided a clearer understanding of the general phenomenon presented when UAVs approach structures and attempts to fill the gap of knowledge regarding minimum requirements and criterion for the use of UAS technologies in inspection of structures.</p>
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Fernandes, João Nuno Duarte. "Risk-based railway infrastructure management systems." Doctoral thesis, 2021. http://hdl.handle.net/1822/76056.
Full textAbstract:
Tese de Doutoramento em Engenharia Civil<br>A gestão de ativos de infraestruturas envolve diversos processos relacionados com o seu ciclo de vida nomeadamente na avaliação do estado de conservação, modelação da degradação, manutenção e otimização. Entre os vários ativos que compõem a rede ferroviária, as pontes sao ativos valiosos para a rede ferroviária, uma vez que permitem cruzar determinados obstáculos tais como rios, vales, entre outros. No entanto, esses tipos de estruturas estão expostos a varias ameaças que podem causar degradação severa a longo prazo ou a curto prazo em caso de eventos extremos. Dessa forma, a falta de manutenção pode resultar em grandes consequências indesejáveis tanto para a estrutura, colapso parcial ou total do sistema, como para as pessoas.
Além disso, diversos estudos tem sido propostos por diferentes autores relativo a analise Os-recuperação apps um evento extremo por meio do calculo da resiliência. A resiliência representa a capacidade da infraestrutura de se recuperar de eventos extremos e representa um indicador valioso para estimar as dimensões das consequências.
0 principal objetivo desta investigação é contribuir para uma evolução da pratica atual de monitorização de infraestruturas em Portugal, através da proposta de uma metodologia de gestão baseada no risco e na resiliência. A metodologia desenvolvida inclui a estimativa de modelos de degradação que contemplam a degradação devido a eventos como corrosão e eventos como terremotos, inundações, entre outros. Além disso, a metodologia desenvolvida sugere diferentes pianos de manutenção para um determinado período do ciclo de vida. Algoritmos genéticos sao aqui adotados para otimizar problemas com dois objetivos conflituosos entre si, desempenho e custos. Estes conceitos sao validados individualmente através dos capítulos desta tese e validados no capitulo 7 num estudo de caso de uma ponte ferroviária de beta() armado localizada em Portugal.<br>Asset management of infrastructures involves several processes related with its life cycle namely on the assessment of the condition state, degradation modelling, maintenance, and optimization. Among the several assets that compose the railway network, bridges are valuable assets for the rail network by providing cross critical links such as waterways, valleys, and other types of facilities. However, these types of structures are exposed to several threats that can cause severe degradation at long term or at short term in case of hazard events. In this way, the lack of maintenance can result in large undesirable consequences either for the structure, such as partial or total collapse of the system, or for the people. Moreover, several studies have been proposed by different authors concerning the post recovery analysis after a hazard event through the calculation of the resilience. Resilience stands for the ability of the infrastructure to recovery from hazard events and represents a valuable indicator to estimate the dimensions of the consequences. The main goal of this research is to contribute to an evolution of the current practice of infrastructure monitoring in Portugal by proposing a management methodology based on the risk and on the resilience. The developed framework includes the estimation of degradation models that captures degradation due to events such as corrosion and events such as earthquakes, floods, among others. Moreover, the developed methodology is capable of suggesting different maintenance plans for a certain life cycle period. Genetic Algorithms are here employed to optimize problems with two different conflicting objectives, performance and costs. These concepts are validated individually through the chapters of this thesis and validated in the chapter 7 in a case study of a reinforced concrete railway bridge located in Portugal.
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Engelkemeir, Frederick Donald. "Development of an advanced electrical system for a solar powered racing vehicle with an emphasis on the battery protection and management system." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-3583.
Full textAbstract:
This thesis describes the development of an electrical system for a solar powered racing vehicle with en emphasis on the Battery Protection System (BPS). This battery protection system was designed for the UTSVT’s (University of Texas Solar Vehicles Team) solar powered vehicle, the Samsung Solorean. The system is required due to the dangers of the lithium-ion cobalt battery chemistry. The system monitors the voltage, temperature, and current of each battery module in the 22 module battery pack and will physically isolate the pack from the rest of the vehicle with a high-current electromechanical contactor if any parameter is outside of the safe range. The system can be expanded to monitor any number of series battery cells. The system uses a master-slave microcontroller architecture with a single master microcontroller that interrogates several slave microcontroller boards for readings over a common serial bus. The system uses a new voltage sensing ASIC to monitor cell voltages, along with an analog current output device to measure temperature and a hall-effect device to measure current. The system was a complete success and has allowed the UT solar car to finish the American Solar Challenge cross-country “Rayce.”<br>text
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"Systems Health Management and Prognosis using Physics Based Modeling and Machine Learning." Doctoral diss., 2016. http://hdl.handle.net/2286/R.I.40184.
Full textAbstract:
abstract: There is a concerted effort in developing robust systems health monitoring/management (SHM) technology as a means to reduce the life cycle costs, improve availability, extend life and minimize downtime of various platforms including aerospace and civil infrastructure. The implementation of a robust SHM system requires a collaborative effort in a variety of areas such as sensor development, damage detection and localization, physics based models, and prognosis models for residual useful life (RUL) estimation. Damage localization and prediction is further complicated by geometric, material, loading, and environmental variabilities. Therefore, it is essential to develop robust SHM methodologies by taking into account such uncertainties. In this research, damage localization and RUL estimation of two different physical systems are addressed: (i) fatigue crack propagation in metallic materials under complex multiaxial loading and (ii) temporal scour prediction near bridge piers. With little modifications, the methodologies developed can be applied to other systems.
Current practice in fatigue life prediction is based on either physics based modeling or data-driven methods, and is limited to predicting RUL for simple geometries under uniaxial loading conditions. In this research, crack initiation and propagation behavior under uniaxial and complex biaxial fatigue loading is addressed. The crack propagation behavior is studied by performing extensive material characterization and fatigue testing under in-plane biaxial loading, both in-phase and out-of-phase, with different biaxiality ratios. A hybrid prognosis model, which combines machine learning with physics based modeling, is developed to account for the uncertainties in crack propagation and fatigue life prediction due to variabilities in material microstructural characteristics, crack localization information and environmental changes. The methodology iteratively combines localization information with hybrid prognosis models using sequential Bayesian techniques. The results show significant improvements in the localization and prediction accuracy under varying temperature.
For civil infrastructure, especially bridges, pier scour is a major failure mechanism. Currently available techniques are developed from a design perspective and provide highly conservative scour estimates. In this research, a fully probabilistic scour prediction methodology is developed using machine learning to accurately predict scour in real-time under varying flow conditions.<br>Dissertation/Thesis<br>Doctoral Dissertation Mechanical Engineering 2016
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(6620411), Leslie E. Campbell. "A Benchmark for Evaluating Performance in Visual Inspection of Steel Bridge Members and Strategies for Improvement." Thesis, 2019.
Find full textAbstract:
<p></p><p>Visual inspection is the primary means of ensuring the
safety and functionality of in-service bridges in the United States and owners spend considerable
resources on such inspections. While the
Federal Highway Administration (FHWA) and many state departments of
transportation have guidelines related to inspector qualification, training,
and certification, an inspector’s actual capability to identify defects in the
field under these guidelines is unknown.
This research aimed to address the knowledge gap
surrounding visual inspection performance for steel bridges in order to support
future advances in inspection and design procedures. Focusing primarily on fatigue crack detection,
this research also considered the ability of inspectors to accurately and consistently
estimate section loss in steel bridge members.
</p>
<p> </p>
<p>Inspection
performance was evaluated through a series of simulated bridge inspections
performed in representative in-situ conditions. First, this research describes the results
from 30 hands-on, visual inspections performed on full size bridge specimens
with known fatigue cracks. Probability
of Detection (POD) curves were fit to the inspection results and the 50% and 90%
detection rate crack lengths were determined. The variability in performance was large, and
only a small amount of the variance could be explained by individual characteristics
or environmental conditions. Based on
the results, recommendations for improved training methods, inspection procedures,
and equipment were developed. Above all, establishment of a
performance based qualification system for bridge inspectors is recommended to
confirm that a satisfactory level of performance is consistently achieved in
the field. </p>
<p> </p>
<p>Long term, managing agencies may eschew traditional hands-on
bridge inspection methods in favor of emerging technologies imagined to provide
improved results and fewer logistical challenges. This research investigated the potential for
unmanned aircraft system (UAS) assistance during visual inspection of steel
bridges. Using the same specimens as in the hands-on inspections, four
UAS-assisted field inspections and 19 UAS-assisted desk inspections were performed. A direct comparison was made between
performance in the hands-on and UAS-assisted inspections, as well as between
performance in the two types of UAS-assisted inspections. Again, significant variability was present in
the results suggesting that human factors continue to have a substantial influence
on inspection performance, regardless of inspection method. </p>
<p> </p>
<p>Finally, to expand the findings from the crack detection
inspections, the lower chord from a deck truss was used to investigate
variability in the inspection of severely corroded steel tension members. Five inspectors performed a hands-on
inspection of the specimen and four engineers calculated the load rating for
the same specimen. Significant
variability was observed in how inspectors recorded thickness measurements
during the inspections and engineers interpreted the inspection reports and
applied the code requirements. </p><br><p></p>