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Title: STATISTICAL METHODS FOR LARGE-SCALE TRANSPORTATION NETWORK TRAFFIC VOLUME FORECASTING
Creator: Meng, Xiao
Date: 2012-11-27, 2012-12
Description: Forecasting is the procedure of making declarations about future events whose actual outcomes have not yet been observed. A lot of decisions...
Show moreForecasting is the procedure of making declarations about future events whose actual outcomes have not yet been observed. A lot of decisions are made based on predictions of future unknown events. Knowing the essence of forecasting, it is not hard to interpret what traffic volume forecasting is. Traffic volume forecasting is the process of estimating the number of vehicles that will be on a planned highway in the future. It plays important roles in different aspects of transportation and related field, such as highway level of service analysis, measure of effectiveness, highway improvement and expansion, geometric design and air quality analysis, etc. A good forecast is needed for decision making in future land use and transportation planning. City and county planners can provide useful information about land use planning and projected developments. County engineers may provide information about future county projects that may cause detours and changes in traffic patterns along a trunk highway. Highway designers need forecasted traffic volumes to ensure proper geometric designs. Since short term forecasting has been a hot topic on research, many statistical methods have been used, such as the mean, historical moving average, exponential smoothing, and autoregressive integrated moving average. Among them, Box Jenkins method (Autoregressive Integrated Moving Average) has been found as the best model on forecasting of time series data with seasonality and trend.
M.S. in Civil Engineering, December 2012
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Title: BICYCLE CRASH ANALYSIS IN CHICAGO
Creator: Van Nortwick, Taylor Wade
Date: 2013, 2013-07
Description: The United States is making big plans for improvements in bicycle infrastructure. To best understand if the improvements will be successful in...
Show moreThe United States is making big plans for improvements in bicycle infrastructure. To best understand if the improvements will be successful in creating a safe network, a study was done to determine contributing factors in bicycle crashes. Bicycle and motor vehicle crash data from around Chicago between 2005 and 2011 was analyzed for significant factors in infrastructure, cyclist and motorist attributes. Temperature was used as a predictor of bicycle traffic due to the seasonality of bicycling in Chicago. It was found that more bicycles and vehicles result in higher crash rates. It was also found that on -street parallel parking, signalized, skewed and multiple legged intersections lead to higher crash rates.
M.S. in Civil Engineering, July 2013
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Title: DEVELOPMENT AND APPLICATION OF THE KIRIE WASTEWATER TREATMENT PLANT MODEL
Creator: Mendez, Thomas E.
Date: 2012-07-15, 2012-07
Description: The Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) is tasked with protecting the public’s water supply and improving the...
Show moreThe Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) is tasked with protecting the public’s water supply and improving the quality of water in their service area’s watercourses. Principal in this mission are the seven wastewater treatment plants that are operated by MWRDGC. The greater Chicago area possesses a combined sewer system (CSS) that combines sanitary sewage and stormwater runoff. Because of this CSS, water reclamation plants are burdened with not only processing sewage and sanitary waste, but also stormwater runoff. As a result there can be a large variation in water quality and quantity. MWRDGC’s newest water reclamation plant is the James C. Kirie Water Reclamation Plant, which was completed in 1980. This plant operates as a nitrification plant with no separate distinct denitrification process. It is important to note that no clearly defined unit processes such as nitrification towers are utilized at the Kirie Water Reclamation Plant. Nitrification occurs primarily in the aeration basins and is currently sufficient to meet water quality standards. However, because of the current regulatory climate, stricter standards on effluent discharge are likely in the near future especially with respect to nutrients. Stricter standards on total nitrogen in effluent instead of the current ammonia limits are one such expected water quality change. As a result of this expectation, modeling modifications and processes at a treatment plant can be a key tool in adjusting to evolving standards. Because water reclamation plants vary greatly depending on their technology, influent and processes, computer modeling provides a convenient way to assess how the plant will react to dynamic changes in influent quality and still be able to meet static effluent standards. Although computer modeling has been applied to water reclamation plants for some time now, there are no clearly defined or accepted protocols for this modeling. Combined with the variation exhibited by various types of water reclamation plants, often modeling protocols must be custom created for individual plants or types of plants. What follows is a study and simulation of the Kirie Water Reclamation Plant. Simulation was used to examine wet weather events at the Kirie Water Reclamation Plant. Wet weather phenomena were explored in step-wise manner to determine the relative effects of different perturbations in influent water quality and quantity. The results show the various effects in effluent quality depending upon the variable or combination of variables deviated. Deviations in temperature and flow dominate all other variations simulated and result in the largest effect on effluent water quality. Deviations of 50% to both temperature and flow simultaneously yielded an increase in effluent BOD and NH3 at twice and six times the steady state values, respectively.
M.S. in Environmental Engineering, July 2012
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Title: SAFETY TRAINING IN CONSTRUCTION
Creator: Demirkesen, Sevilay
Date: 2011-11-29, 2011-12
Description: The construction industry is one of the most hazardous industries. Therefore, the ways to reduce the number of risks have been a concern for...
Show moreThe construction industry is one of the most hazardous industries. Therefore, the ways to reduce the number of risks have been a concern for construction companies. Safety training is considered as one of the most efficient ways of improving safety record. Therefore, this study aimed to describe the best safety training methods and the most efficient organization in safety training. The study also aimed to show how to take best safety measures to protect construction workers. In this thesis study, a questionnaire was conducted in order to investigate the achievement of safety learning, challenges in a safety training program and the methods of improving safety record. Thus, the questionnaire was e-mailed to 400 contractors in US. The data collected also indicated the importance of safety training in companies’ success in the industry. Additionally, this study presents recommendations on how companies could improve their safety record.
M.S. in Civil Engineering, December 2011
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Title: PROPOSITION AND EVALUATION OF A NEW DAMPER, CALLED ROTATIONAL CYLINDRICAL FRICTION DAMPER (RCFD)
Creator: Divani, Abbass
Date: 2013, 2013-12
Description: The objective of this study is to propose and evaluate an innovative frictional damper for structural systems, called Rotational Cylindrical...
Show moreThe objective of this study is to propose and evaluate an innovative frictional damper for structural systems, called Rotational Cylindrical Friction Damper (RCFD), which does not bear limitation of previously proposed systems and yet maintains their advantages. Different kinds of energy dissipaters have been studied and used in structural systems in recent years. They perform more effectively compared to structures without any energy dissipater. Each of previously employed devices has its advantages and limitations. In this report, applicability of previous energy dissipaters will be investigated; then the proposed damper, RCFD, will be introduced, and the performance of RCFD will be evaluated under lateral load using ABAQUS software. RCFD consists of a shaft, a cylinder and proper assembly of braces so that the bracing members make the cylinder and shaft move in opposite circular directions under defined load. The assemblage of braces depends on type of bracing system that is employed. When load in bracing member exceeds the buckling load of the member, it overcomes the friction between the shaft and inner surface of the cylinder and while providing the ductility demand of the structure, it absorbs the energy of the seismic load, and it will work like a safety valve to protect main structural members from inelastic deformation. In spite of other types of frictional dampers, RCFD does not use and reduces the construction cost of high strength bolts. There is no limitation for the size and fitness of the bracing members more than that is for conventional design of braced frames. When we prove the performance of RCFD, some of the requirements of conventional design such as requirement of section F2 of Seismic Provisions for Structural Steel Buildings, AISC 341-10, will be eliminated. The pressure needed for developing friction is provided by heating the shaft and placing it into the cylinder with slightly smaller xiii diameter. It is simple to design and construct and does not have the limitation of other kinds of frictional damper systems. It can also be installed with little or no modification on any kind of Braced Frames or to retrofit Moment Frames. In this study, RCFD will be installed and evaluated on an Inverted V Concentrically Braced Frame, although installation of the RCFD on X Braced frame will be illustrated.
M.S. in Civil Engineering, December 2013
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Title: STRUCTURAL SEISMIC PERFORMANCE EVALUATION WITH CONSIDERATION OF ECONOMIC VULNERABILITY
Creator: Romero, Daniela Zuloaga
Date: 2014, 2014-05
Description: Performance evaluation of structures has until now been based on evaluation of maximum displacements, interstory drifts, deformation patterns,...
Show morePerformance evaluation of structures has until now been based on evaluation of maximum displacements, interstory drifts, deformation patterns, ductility and other similar parameters; a relative economic loss estimation as a performance measure for the structure is the next step that follows, and is what has been investigated in this work. For this study a steel mid-rise structure was designed according to code provisions using modal spectral analysis, after which it was subjected to an Incremental Dynamic Analysis (IDA) procedure to evaluate the capacity curve of the building. The capacity analysis was then used to determine damage states and compute fragility curves. Finally, economic relative loss values were assigned to represent each designated damage state, for which the mean damage ratio was computed (in terms of economic loss relative to total replacement cost) as a function of spectral displacement.
M.S. in Civil Engineering, May 2014
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Title: AN ASSESSMENT OF HEAT PUMP APPLICATION AT WATER TREATMENT FACILITIES-THAT USE SURFACE WATER
Creator: Yan, Wenpeng
Date: 2012-07-17, 2012-07
Description: Energy-efficient heat pumps have been applied in the United States and other regions of the world for decades. Geothermal heat pumps have been...
Show moreEnergy-efficient heat pumps have been applied in the United States and other regions of the world for decades. Geothermal heat pumps have been used, but their application is not wide spread due to the high cost of drilling and installing a ground loop. An alternative choice for space conditioning at municipal water utilities is a surface water source heat pump. Because treated surface water is readily available and it exists in a relatively narrow temperature range it could be useful heat transfer fluid. In this project the economic benefits and greenhouse gas emissions of a heat pump system for a building in NE Illinois are analyzed. Heating and cooling requirements for a hypothetical a 1000 m2 space at a drinking water treatment plant are considered. The analysis includes initial, operating and maintenance costs as well as greenhouse gas emissions, between a heat pump system and a conventional natural gas furnace and air-conditioner. The cost savings in this project for the heat pump system were from $39900 to $41511 over the life cycle of the system depending on the different efficiency level of the heat pump system. Surprisingly the initial cost of the standard efficiency heat pump system is lower than the conventional NGAC system. There is no need to take time to make up the additional initial cost. Surface water heat pumps operating at different efficiency level produce less greenhouse gas than the conventional NGAC system. The CO2 emission reduction could be as high as 73%.
M.S. in Environmental Engineering, July 2012
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Title: A study of the effects produced on Portland cement by the addition of various percentages of hydrated lime
Creator: Knuepfer, Claude Albert, Hook, Leonard Doolittle
Date: 2009, 1915
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/studyofeffectspr00knue
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 99

Title: OPTIMAL MATERIAL SELECTION MODEL FOR LEED CERTIFICATION USING GENETIC ALGORITHMS
Creator: Kim, Taehyoung
Date: 2012-12-16, 2012-12
Description: Material selection is an important part of building design because it has great impact on the environment, as buildings during/after...
Show moreMaterial selection is an important part of building design because it has great impact on the environment, as buildings during/after construction are responsible for a large portion of carbon emissions and use many resources and considerable energy. Selecting green materials is an emergent issue in both design firms and construction companies. Green building certification such as LEED systems originated from the desire to improve environmental, economic, financial, and social benefits. The current approach to material selection for sustainability is based only on the designer’s past experiences. An arbitrary approach based on subjective opinions causes unnecessary expense, longer construction duration, and failure to meet desired environmental goals. In order to help decision-makers with the selection of the right materials, this study proposes a model that uses Genetic Algorithms in MATLAB and that optimizes the desired points in LEED Certification within budget constraints. This model can be applied to any project that is pursuing LEED Certification. If the user specifies the desired LEED points, the system recommends the least expensive combination of materials extracted from a database containing detailed information about a large member of materials. The modified model uses multi-objective genetic algorithms to establish trade-off between budget constraints and LEED points. The proposed system is expected to be a useful tool for inexperienced designers and a valuable guideline for designers with extensive experience.
M.S. in Civil Engineering, December 2012
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Title: SEISMIC STRUCTURAL ANALYSIS USING INTERVAL GROUND MOTION
Creator: Venezia, Adam
Date: 2011-12-05, 2011-12
Description: Seismic analysis is a crucial procedure for the design of a structure subjected to ground motion. In conventional seismic analysis procedures,...
Show moreSeismic analysis is a crucial procedure for the design of a structure subjected to ground motion. In conventional seismic analysis procedures, a structure is subjected to a limited number of earthquake excitations. Moreover, these procedures do not consider the presence of variations and uncertainties in those excitations. Interval analysis is one method capable of accounting for both of these limitations. In this work, a new method for seismic structural analysis, with interval uncertainty in the response spectrum, is developed, which is capable of obtaining the bounds of the dynamic response of a structure. This method is hereinafter referred to as Interval Ground Motion Analysis (IGMA). In this method, first, various response spectra are combined as an interval function, referred to as an interval response spectrum. Then, the response spectrum analysis is performed using the developed interval response spectrum, and the bounds of the dynamic response of the structure are obtained. It is shown that obtaining these bounds is computationally feasible and does not require iterative procedures such as Monte Carlo simulation. Numerical example problems, which illustrate the developed algorithm, are presented, along with a comparison of solutions obtained by another solution method.
M.S. in Civil Engineering, December 2011
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Title: A PARAMETRIC STUDY OF THE THERMAL PERFORMANCE OF DIFFERENT WALL SYSTEMS AT VARIOUS CLIMATE ZONES
Creator: Lai, Se Yen
Date: 2013, 2013-12
Description: One of the most common energy conservative measures used is designing an air-tight and a well-insulated envelope. While there is an abundance...
Show moreOne of the most common energy conservative measures used is designing an air-tight and a well-insulated envelope. While there is an abundance of high-efficiency building envelope designs in the market which offer low thermal conductivity and high R-values as well as various studies on the thermal performance of various wall constructions, the results were often based on simplified study model and are not incompliance with the current building code. Most studies also focus on only one particular climate zone and one type of wall construction. This research aims to examine the thermal performance of different types of wall construction based on the traditional building envelope design materials in various climate zones based on insulation and air cavity placements on a non-simplified reference model that is used for construction. Study models developed are incompliance with the American Society of Heating, Refrigerating, and Air-Conditioning Engineers [ASHRAE] 90.1-2010 based on U.S. Department of Energy [DOE] Commercial Prototype Building Model. The thermal performance of the wall will be determined using two different methods. The first method will be using Building Energy Modeling [BEM] software where the exterior wall construction will be modified based on DOE reference models where the results for the overall annual energy consumption [AEC] will be compared. AEC results showed small differences between study models which are negligible. The second method is the Total Thermal Constant [TTC] method, where the thermal lag will be compared. The building structures that will be used are a steel-framed structure which represents a medium office and a wood-framed structure which represents a quick service restaurant. TTC results were able to determine the least favorable study model.
M.S. in Civil Engineering, December 2013
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Title: APPLICABILITY OF THE INTERVAL ANALYSIS METHOD TO RELIABILITY ASSESSMENT OF STRUCTURES
Creator: Taha, Raguez A.
Date: 2012-11-26, 2012-12
Description: The scope of this study is focused on the applicability of the interval method to the reliability analysis of structures. The study includes...
Show moreThe scope of this study is focused on the applicability of the interval method to the reliability analysis of structures. The study includes using the traditional probability methods in several applications and comparing the results with the interval analysis. Accordingly, the interval arithmetic rules are applied in several examples and the results are compared with those from the traditional probability theory concepts. Specifically, the procedure for using the interval methods was applied to the development of the probability of failure for a simple structural member; and for a link in a network system. Through three simple examples, the research shows that the interval method offers comparable results with those from the traditional first-order reliability method. The procedure based on the interval method, however, may offer advantages, especially in cases where the uncertainties in various parameters describing the reliability of a system are large. In the presence of large uncertainties, the traditional methods of reliability analysis, based on the first order approximation, may lose their accuracy. In these cases, the interval method may offer a simple method yet with more accurate results.
M.S. in Civil Engineering, December 2012
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Title: Street pavement for Rushville, Illinois
Date: 2009, 1914
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/streetpavementfo00pome
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket

Title: INFORMATION PROPAGATION DYNAMIC THROUGH VEHICLE TO VEHICLE COMMUNICATION NETWORK ON A ROAD SEGMENT
Creator: Wang, Lu
Date: 2015, 2015-12
Description: Vehicle-to-vehicle communication system enables vehicles to share various traffic information such as road surface condition, real-time...
Show moreVehicle-to-vehicle communication system enables vehicles to share various traffic information such as road surface condition, real-time traffic congestion, crashing alert or weather situation. Thus, it has a great potential to improve traffic safety, mobility and environmental sustainability. To grant this great promise, information availability plays a critical roles. Accordingly, many previous studies have investigated statistic characteristics (such as mean and variance) of information propagation (such as speed/time delay via instantaneous transmission, connectivity, etc.) integrating traffic flow features. However, few of them are able to capture the information spread dynamics based on V2V. Motivated by this view, this research seeks to develop a discrete mathematical approach to capture information coverage dynamics built upon traffic flow dynamics, which is described by discrete traffic flow dynamics, i.e., cell transmission model. The approach is entailed by developed mathematical model to capture inner-cell information propagation delay and inter-cell transmission based on the proposed information-traffic cell transmission model. The development of the proposed methodology considers a single or two piece(s) of information is (are) sequentially landed on a one-way or two-way road segment underVehicle-to-vehicle communication system enables vehicles to share various traffic information such as road surface condition, real-time traffic congestion, crashing alert or weather situation. Thus, it has a great potential to improve traffic safety, mobility and environmental sustainability. To grant this great promise, information availability plays a critical roles. Accordingly, many previous studies have investigated statistic characteristics (such as mean and variance) of information propagation (such as speed/time delay via instantaneous transmission, connectivity, etc.) integrating traffic flow features. However, few of them are able to capture the information spread dynamics based on V2V. Motivated by this view, this research seeks to develop a discrete mathematical approach to capture information coverage dynamics built upon traffic flow dynamics, which is described by discrete traffic flow dynamics, i.e., cell transmission model. The approach is entailed by developed mathematical model to capture inner-cell information propagation delay and inter-cell transmission based on the proposed information-traffic cell transmission model. The development of the proposed methodology considers a single or two piece(s) of information is (are) sequentially landed on a one-way or two-way road segment under sparse or congested traffic flow considered. Next-Generation simulation field data and Paramics simulated data are used to verify the accuracy of the experiments. Our experimental results show that the proposed model can accurately track information spread dynamics with mean absolute error less than 5% over all experiments. Key words: Vehicle-to-vehicle communication system; cell transmission model; time delay; information propagation coverage.
M.S. in Civil Engineering, December 2015
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Title: Structural considerations in the design of modern abattoirs and cold storage warehouses
Creator: Edlund, Lawrence L
Date: 2009, 1920
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/structuralconsid00edlu
Thesis (B.S.)--Armour Institute of Technology

Title: Mycoflora of Indoor Dust and Alternaria Alternata Growth on Building Materials
Creator: Simpson, Stacy
Date: 2011-10-27, 2011-12
Description: Alternaria alternata, a clinically significant mold species is associated with allergic disease and asthma. An indoor growth of A. alternata...
Show moreAlternaria alternata, a clinically significant mold species is associated with allergic disease and asthma. An indoor growth of A. alternata may initiate atopic symptoms, accumulate in dusts, and discolor and deteriorate indoor building materials. Environmental control should be the initial approach to maintain a healthy indoor environment and manage allergic diseases. The current thesis investigated indoor dusts from various environments for mold spores and Alt a 1. Laboratory studies were carried out to determine if or which commercially available mold-resistant treatments and building materials could efficiently decrease A. alternata growth and Alt a 1. The mycoflora of indoor dusts was microscopically examined and the clinically significant allergen from A. alternata, Alt a 1 was measured in sampled dusts using a monoclonal anti-recombinant Alt a 1 (rAlt a 1) enzyme linked immuno-sorbent assay (ELISA). To investigate building material susceptibility untreated, mildew-resistant painted, and commercially available biocide treated building materials were inoculated with A. alternata spores, incubated in a humidity controlled chamber, and compared for mold growth and the presence of Alt a 1. A photo-monitoring technique was used to survey and determine mold growth surface area coverage. Alt a 1 immuno-reactivity of superficial mold growths was analyzed with the ELISA. The microscopic speciation of mold spores indicated that a diverse mycoflora can be found in indoor dusts. Although A. alternata was found in low concentrations in a few samples, Alt a 1was below the limit of detection. Nevertheless, mold spores can significantly contribute to the complexity of indoor dusts. A. alternata grew on all tested building materials but both painted and treated building materials inhibited mold growth in comparison to untreated samples. Not all material surfaces contained detectable levels of Alt a 1. Comparisons between untreated and painted building material groups indicated that a significant difference between the Alt a 1 accumulation content could not be established. To establish a standard sampling protocol and reliable prevention methods for mold contamination and exposure more knowledge about indoor molds must be gained.
M.S. in Environmental Engineering, December 2011
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Title: WEB-BASED CONTEMPORANEOUS DELAY ANALYSIS
Creator: Pektas, Murat
Date: 2011-11-22, 2011-12
Description: The construction industry is fragmented due to the many stakeholders and the diverse phases involved in a construction project. On time,...
Show moreThe construction industry is fragmented due to the many stakeholders and the diverse phases involved in a construction project. On time, within budget, with required quality are essentials of a successful project. However, most construction projects are faced with delays, which obstruct success. To recover the damage caused by delays, both the delays and the parties responsible for them should be identified accurately. Daily window delay analysis outperforms other delay analysis methods, but it requires intensive day-by-day information. The information flow among the project stakeholders must be smooth and speedy at all stages of the production process not only to achieve the basic project objectives but also to let project stakeholders recognize the delays and the parties responsible for them in order to recover time and cost. The Internet is attractive for transferring information promptly and economically with no regional or temporal borders. To merge the power of the Internet and to ease time consuming delay analysis, a web-based application is proposed to analyze delays effectively and contemporaneously, to reduce time and cost, and to provide historical data. The application considers the day-by-day variation in critical path(s) during the project life cycle. The application gives accurate and repeatable results for apportioning project delays, accelerations and decelerations among involved parties. The manual effort required by traditional systems is minimized with the application’s simple, easy to use, yet effective and highly automated features. Moreover, the database structure of the application is designed to store and manage more than one project at a time to let its users calculate the overall performance of the company including all projects, and to calculate average durations for activities that can come up in future projects.
M.S. in Civil Engineering, December 2011
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Title: A METHODOLOGY FOR MAJOR BUS ROUTE RESCHEDULING TO IMPROVE TRANSIT PERFORMANCE
Creator: Lu, Xi
Date: 2012-08-01, 2012-07
Description: In a period of growing transit operating deficits, increasing attention and concern is being directed at both the decreasing levels of...
Show moreIn a period of growing transit operating deficits, increasing attention and concern is being directed at both the decreasing levels of productivity of transit systems in general and the broad differences in measured service performance compiled for various transit systems. The purpose of this study is an assist public transit managers by providing them with a mathematical technique to analyze the efficiency with which serviced is produced and the effectiveness with which it is consumed. By providing the analysis model which not requires an extensive amount of data, the operator can have tool for decision-making of profit and market growth. Thus, transit managers will be able to access the performance of the agency and areas where improvements can be realistically achieved. Using the urban operation of the Chicago Transit Authority, a transit performance model is developed to analysis efficiency and effectiveness of the city's bus system. As the system exists, there are 144 bus routes start and end, frequency of dispatching buses and ridership changes from Weekdays and Weekend, peak hour and off-peak hour. In many of these routes, vehicles are used inefficiently and ineffectively, only a few passengers carried in some routes in off-peak hour, yet in other routes through the Central Business District (CBD) area, there are always not enough buses in peak hour. Also, some routes cannot provide enough on-time arrival service and some special group like elderly and handicapped cannot receive enough service in certain area. The goal of case research is to determine to understand the transit performance of Chicago Transit Authority and to select the optimal improvement projects to maximize the performance in term of economy and social equity.
M.S. in Civil Engineering, July 2012
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Title: DAMAGE DETECTION OF STRUCTURES USING INTERVAL FINITE ELEMENT METHOD
Creator: Venkitaraman, Shyamala
Date: 2012-04-16, 2012-05
Description: Health assessment and damage detection for existing structures is an essential procedure for their safe and reliable operation so that any...
Show moreHealth assessment and damage detection for existing structures is an essential procedure for their safe and reliable operation so that any catastrophic failure may be prevented in a timely manner. However, results obtained from a health assessment of a structure possess uncertainties in measurements, system properties and loads. Furthermore, the conventional deterministic structural analyses are incapable of considering these uncertainties, thereby resulting in error when estimating the state of health of a structure. Interval (unknown-but-bounded) representation is one method to quantify uncertainty in a physical system. Using an interval variable, the uncertain parameter is bounded between extreme values. In this work, a new method for damage assessment of structures is developed that utilizes the results from structural health assessment as uncertain input parameters in an interval finite element analysis scheme. This method, due to its capability of considering uncertainties, offers a more robust process for estimating the possible existence of damage and overall health of the structure. As an illustrative example, the method is applied for a failed sign support structure. First, the structure's response from previous health assessment procedure was used to construct uncertain interval responses. Then using these interval responses as input parameters, an interval finite element method was performed. The results of the analysis verify and correlate with the failure location of the actual structure. Moreover, the lifetime assessment of the structure obtained from this method is the lower bound of, and correlates with the actual failure time of the structure.
M.S. in Civil Engineering, May 2012
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Title: DETERMINATION OF REDUNDANCY IN STRUCTURES USING INTERVAL UNCERTAINTY ANALYSIS
Creator: Amirshaghaghi, Sayeh
Date: 2014, 2014-05
Description: Existence of redundancy in structures plays an important role in increasing their safety and reliability. However, using state-of-the-art...
Show moreExistence of redundancy in structures plays an important role in increasing their safety and reliability. However, using state-of-the-art deterministic and probabilistic approaches, all possibilities for estimation of redundancy (e.g. due to occurrence of different damage scenarios) have not been considered. One of the methods to quantify the presence of uncertainties in a system is to use interval variables. In this work, a new method for estimating the redundancy using interval structural analysis is developed. This method, hereafter referred to as Interval Redundancy Analysis (IRA), is robust and considers possibilities of strength reduction for each element leading to failure. Independent intervals for reduction of the strength for five damage scenarios of intact, slightly damage, moderately damaged, severely damaged, and completely damaged as well as strength of each element are considered. A numerical example to show the behavior of the developed method with comparison to Monte-Carlo simulation results is presented.
M.S. in Civil Engineering, May 2014
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