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Title: NUMERICAL ANALYSIS OF NON-DUCTILE BRACED FRAME DUE TO DYNAMIC LOADS
Creator: Keivan Esfahani, Ashkan
Date: 2014, 2014-05
Description: In recent years, typical steel construction in regions of high seismic risk has shifted from moment-resisting frames to concentrically braced...
Show moreIn recent years, typical steel construction in regions of high seismic risk has shifted from moment-resisting frames to concentrically braced frames. As a result of the increased popularity of braced frames, the poor performance of some conventionally braced frames in past earthquakes, and the limited experimental data available on the inelastic response and the failure characteristics of braced-frame systems, a series of experimental and analytical investigations were initiated. Steel concentrically braced frames are common lateral force resisting systems in both new construction and existing buildings. However, the seismic behavior of braced frames designed prior to the adoption of capacity design principles in the 1980s is generally not well understood despite their widespread presence. These older braced frames, termed non-seismic concentrically braced frames (NCBFs) are the subject of a research project titled “NEESR: Collaborative Developments for Seismic Rehabilitation of Vulnerable Braced Frames” that seeks to evaluate NCBFs and determine retrofit strategies. In this project two tests were conducted. First Test examined a full scale two story NCBF in the inverted V configuration subjected to quasistatic cyclic load and this specimen contained a bottom story beam that is considered weak in capacity design. Second Test examined a post-earthquake repair scenario using the damaged NCBF-INV-1 frame in which the bottom story braces and gusset plates were removed and replaced with seismically compact braces with connection designed for in plane buckling. In this work, finite element models developed in Abaqus were validated using data collected from these tests. The outcomes of this research will be a greater understanding of seismic performance of NCBFs, the development of rehabilitation strategies for vulnerable NCBFs, and a robust technique for modeling NCBFs.
M.S. in Civil Engineering, May 2014
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Title: DYNAMIC ANALYSIS OF UNCERTAIN STRUCTURES USING IMPRECISE PROBABILIY
Creator: Bergerson, Joshua D.
Date: 2014, 2014-05
Description: A new method for dynamic response spectrum analysis of structures with uncertainty in their mechanical properties utilizing the notion of...
Show moreA new method for dynamic response spectrum analysis of structures with uncertainty in their mechanical properties utilizing the notion of imprecise probability is developed. This finite-element-based method is capable of obtaining probabilistic bounds of the dynamic response of the structure with uncertainty defined by enveloping p-boxes. The developed method obtains probabilistic bounds on 1) the mode shapes, 2) modal coordinates, and 3) modal participation factor, leading to the p-boxes of modal responses. Finally maximum modal responses are combined to obtain the structure’s maximum total response with consideration of uncertainty. Numerical examples demonstrating the developed method are included. Keywords: Structural Dynamics, Uncertainty, Imprecise Probability, P-Box.
PH.D in Civil Engineering, May 2014
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Title: MATERIAL INVENTORY CONTROL AND MANAGEMENT SYSTEM IN CONSTRUCTION USING GIS APPLICATIONS AND A "HYBRID" TRACKING SYSTEM
Creator: Le, Kiet Tuan
Date: 2017, 2017-05
Description: Material inventory control and management is simply the process by which an organization is supplied with the goods and services that it needs...
Show moreMaterial inventory control and management is simply the process by which an organization is supplied with the goods and services that it needs to achieve its objectives of buying, storing and moving materials. There are usually plenty of materials in a construction site. A large amount of stored materials can meet unexpected demands, and can prevent future purchases that can be affected by an escalation of material prices. However, a large amount of stored materials can also cause negative impacts such as increased costs for storing redundant inventory, and decreased construction productivity. Therefore, a proper material inventory control and management system is critical for economy and efficiency in construction projects. A material inventory control and management system consists of two main elements: inventory control and inventory management. Inventory control is the process of monitoring the flow of materials on the construction site beginning when materials are received from manufacturers and ending when those materials are used in production. Inventory management is the practice overseeing and managing the ordering, storage and use of materials on the construction site. In this study, an automated material inventory control and management system is developed using Geographical Information System (GIS) applications and a “hybrid” tracking system to identify the need for materials, order, track, transport, store, control the inventory, circulate on site, and incorporate into production. The proposed system allows users to have access to real-time information about the materials on the construction such as: the arrival of materials, the amount of materials received, the status of materials (either in storage area or in-production), and the up-to-date information about site stocks. Furthermore, the system provides users the ability to make correct and timely decisions regarding materials on the construction site.
Ph.D. in Civil Engineering, May 2017
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Title: INVESTIGATION ON THE INTERACTION BETWEEN NATURAL ORGANIC MATTER AND CALCITE
Creator: Zhu, Junjie
Date: 2012-07-12, 2012-07
Description: Fox River water was supersaturated with respect to calcite; natural organic matter (NOM) might play a key role in this phenomenon. Fox River...
Show moreFox River water was supersaturated with respect to calcite; natural organic matter (NOM) might play a key role in this phenomenon. Fox River NOM (FRNOM) adsorption on the calcite surface is probably an important mechanism to explain this condition. Fox River water contained moderate ultraviolet absorbance (UVA) of NOM (0.19 1/cm), high concentration of calcium (70 mg/L), suspended solids with relatively high specific surface area (SSA) (6.9 m2/g), and moderate pH value (8.4) based on historical data. To test whether the phenomenon was caused by NOM adsorption, a series of experiments was conducted to explore the interaction between NOM and calcite in conditions similar to those of the Fox River. Suwannee River NOM (SRNOM) and Nordic Reservoir NOM (NRNOM) were used as surrogate NOM. The results show that SRNOM inhibited calcite dissolution significantly after 10 min based on measuring of the decrease in the free calcium concentration. The decrease in the free calcium was not solely due to formation of NOM-calcium complexes, because these complexes made up only about 3% of the total free calcium concentration. Therefore, NOM adsorption onto calcite was probably largely responsible for the inhibited calcite activity. Experimental results also showed that NOM adsorption increased with increasing NOM concentration in the range from 2 to 14 mg NOM/L, which is a common range for river water. Higher charge density also seems to promote sorption onto calcite; relative to NRNOM, SRNOM has a higher charge density and SRNOM has a higher affinity for calcite. Other factors that promoted NOM adsorption onto calcite included higher concentration of calcium and larger SSA of calcite seed. Based on water quality characteristics, the Fox River provides a suitable environment for NOM adsorption on calcite, and it seems likely that Fox River NOM (FRNOM) adsorption on calcite can inhibit calcite precipitation. This understanding of interaction between NOM and calcite could be used by WTPs along the Fox River for better optimization and improvement in treatment and operation.
M.S. in Environmental Engineering, July 2012
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Title: CLAIMS IN CONSTRUCTION: ANALYSES OF CLAIMS BETWEEN TRADITIONAL AND GREEN/SUSTAINABLE BUILDING CONSTRUCTION
Creator: Tackey-otoo, Ebenezer
Date: 2014, 2014-07
Description: Construction professionals, irregardless of their experience, go through all these problems. These problems which in turn becomes disputes...
Show moreConstruction professionals, irregardless of their experience, go through all these problems. These problems which in turn becomes disputes arise from the various stages or phases in the construction process - the pre-design stage, the design stage, bidding/negotiating stage and the construction stage. The introduction of green/sustainable building construction has raised a lot of questions in the construction industry. Unlike the traditional building process, disputes in the green building construction process are not well known, with issues ranging from materials through to the certification process. This research seeks to analyze the different disputes that arise from both the traditional and green building processes and determine which process has more risk associated with it.
M.S. in Civil Engineering, July 2014
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Title: INVESTIGATING THE IMPACT OF LOCAL REAL-TIME TRAFFIC INFORMATION PROVISION STRATEGY IN A CONNECTED VEHICLE SYSTEM
Creator: Chen, Shuwei
Date: 2013, 2013-12
Description: Nowadays connected vehicle systems (CVS), including vehicle-to-vehicle communication and vehicle-to-infrastructure communication. CVS has been...
Show moreNowadays connected vehicle systems (CVS), including vehicle-to-vehicle communication and vehicle-to-infrastructure communication. CVS has been recognized as a promising technology, which enables a new generation of in-vehicle routing guidance to help vehicle avoid traffic congestion with real-time traffic information provision and relief traffic congestion in network level. However, since current guidance system mainly relies on independent, selfish-routing mechanism and global real-time traffic information is uniformly provided to all users, it has a great potential that exceeding volume of traffic flow will be guided into some light traffic corridors within a short time period and cause its traffic congestions. This kind of traffic congestion may oscillate between two or several alternative corridors from time to time. Motived by the above view, the proposed research seeks to address this traffic congestion oscillation through a local information provision strategy. The range of the local information is scoped by the minimum bonding rectangle, and ellipse method, and A* algorithm is employed to provide route guidance for vehicles. The performance of the proposed information proposition strategy is measured by the network system travel time (i.e. system cost). A series of experiments, built upon a designed simulation framework using Borman expressway corridor network as test-bed, are conducted to investigate the performance of our information provision strategy under different traffic conditions, penetrations, information update frequency. Our results indicates that the proposed local information proposal strategy outperforms global information provision congested traffic condition. Under medium or high network traffic load, it produces 10-25% system travel time reduction as compared to global information provision case. Moreover, this benefit xii becomes more significant as more vehicle using real-time information to guide their trip (i.e. high penetration). In addition, we find that if the real-time information can be refreshed more frequently, the system performance would be improved further given vehicles are guided based on the proposed information provision strategy. Keyword: real-time information; TIS; simulation.
M.S. in Civil Engineering, December 2013
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Title: UNDERSTANDING DELIBERATIVE AND INTUITIVE DECISION MAKING ABOUT HAZARDS ON CONSTRUCTION SITES
Creator: Saxena, Jaya
Date: 2013, 2013-12
Description: During the course of performing daily tasks, construction workers encounter numerous hazards, such as ladders that are too short to reach the...
Show moreDuring the course of performing daily tasks, construction workers encounter numerous hazards, such as ladders that are too short to reach the work area, energized electrical lines, or inadequate fall protection. When a hazard is encountered, the worker must make a rapid decision about how to respond and whether to take or avoid the risk. The goal of this researchwas to construct a theory about the influence of decision cues on intuitive and deliberative decision-making in high-hazard construction environments. Drawing from Cognitive Continuum Theory, the study specifies a framework for understanding why and how construction workers make decisions that lead to taking or avoiding physical risks when they encounter daily hazards. A secondary aim of the research was to construct a set of hypotheses about how specific decision cues influence whether a worker is more likely to engage their intuitive impulses or to use careful deliberationwhen responding to a hazard. These hypotheses are described and the efficacy of the hypotheses was evaluated using cross-tabulations and nonparametric measures of association. While most of the associations between decision cues and decision mode (i.e., intuition or deliberation) identified in this data set were generally modest, none of the associations were statistically zero, thus indicating that further research is warranted based on theoretical grounds. The qualitative data set was analysed using Decision Trees and Recognition Primed Decision Models.A rigorous program of theory testing is the next logical step to the research, and the thesis thus concludes with numerous suggestions for extending the research and testing the proposed hypotheses
M.S. in Civil Engineering, December 2013
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Title: SERVICEABILITY REQUIREMENTS FOR FLOOR SYSTEMS - A REVIEW OF CURRENT STANDARDS AND PRACTICES
Creator: Jaafari, Chaimaa
Date: 2017, 2017-07
Description: Serviceability requirements are considered in any design to maintain the occupants’ comfort in buildings. Specifically, issues such as floor...
Show moreServiceability requirements are considered in any design to maintain the occupants’ comfort in buildings. Specifically, issues such as floor system deflections and vibrations are two important considerations for design as relate to serviceability. Design codes primarily address the deflection control yet rarely address the vibration. Although the vibration may be related to deflection, maintaining the comfort of occupants will require a detailed study on the level of vibration and its frequency that would be comfortable to the occupants. This research will examine and summarize the serviceability requirements as suggested by various codes and standards and also as suggested by published papers. Specifically, the research focuses on deflection and vibration control for floor systems based on the occupancy and usage and the types of structures and sources of vibrations. Methods to alter existing floor system designs to control vibrations will also be presented. The final research outcome will be a complete document summarizing the findings on what is perceived as good practice for deflection and vibration control for floor system designs in buildings.
M.S. in Civil Engineering, July 2017
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Title: AN INVESTIGATION INTO FIRE ENDURANCE OF WOOD AS A STRUCTURAL MATERIAL IN TALL BUILDINGS
Creator: Ling, Lei
Date: 2014, 2014-05
Description: With the global growth in using timber as a structural material for tall buildings to respond to the trend of sustainability, several timber...
Show moreWith the global growth in using timber as a structural material for tall buildings to respond to the trend of sustainability, several timber buildings from 7 stories to 10 stories have already been built in Europe and Australia. However, in the United States, timber buildings are still limited to 6 or less stories [2]. The motivation of this thesis is to respond to the proposal for fire safety challenges of tall wood buildings issued by the Fire Protection Research Foundation. Since using timber as a structural material is just underway, more related studies from different academic departments and organizations are required in order to characterize the fire performance of tall timber structures, investigate the related challenges and necessary research to achieve a high level of safety and property protection equal to those offered by concrete or steel structures, and promote the development of this type of building systems. This thesis presents a literature review of global design cases of timber buildings, corresponding calculations of fire-resistance rating, recent and ongoing fire tests, and adhesive effects of timber members. A gap analysis was developed, with current challenges of building timber buildings presented, focusing on structural design, fire protection, durability, and code regulations requirements. This gap analysis was then compared with other similar published papers in an attempt to have a better understanding of what areas of research are needed, and suggesting for further studies to promote the idea of using timber as a structural material for tall buildings.
M.S. in Civil Engineering, May 2014
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Title: OPTIMIZATION OF WHOLE HOUSE RETROFIT PACKAGES FOR TARGETING 50% ANNUAL ENERGY USE REDUCTIONS IN PRE-1978 CHICAGOLAND HOMES
Creator: Aguilar Leinartas, Honnie
Date: 2014, 2014-07
Description: New standards and guidelines for energy consumption for the various building sectors in the United States are being developed by organizations...
Show moreNew standards and guidelines for energy consumption for the various building sectors in the United States are being developed by organizations such as the US Department of Energy and others. These typically include goals for all existing residential buildings to pursue deep energy retrofits that reduce their energy consumption by at least 50% relative to the regional average for the 2005 stock of that particular building type by the year 2030. To better inform these energy savings goals, this work relies on whole building energy simulation and optimization to construct a “tool-box” of prescriptive deep energy retrofit solutions that can be applied to a large portion of a subset of the housing stock responsible for a significant portion of residential energy use in the Chicagoland area: existing single-family detached homes built prior to 1978. Ten typology groups of pre-1978 single-family homes were considered for energy retrofit package optimization with a target of 50% annual site energy reductions. Simulations were conducted as a two-step process using sequential search optimization functions in BEopt and EnergyPlus as the simulation engine. First, optimizations of the building enclosure for each typology were performed and the combined highest efficiency, least cost packages were applied to the base models. Second, optimizations based on the modified base models were performed using several heating, ventilation and air-conditioning (HVAC) system options, and an optimal cost-effective package was chosen for each typology based on maximizing annual energy reductions, payback periods, and modified internal rates of return (MIRR). Results reveal that prescriptive deep energy retrofit solutions can indeed be defined for each typology that achieve at least 50% site energy reductions, largely through common envelope retrofit measures for all groups and either upgrades to existing HVAC system efficiency or a conversion to mini-split heat pump (MSHP) systems. A scaling analysis suggests that widespread application of the prescriptive deep energy retrofit solutions described herein to the entire Chicagoland residential building stock could save between $400 and $1300 on energy costs per year per home, depending on typology, summing to a total of approximately $280 million per year in savings across all Chicagoland homes.
M.S. in Civil Engineering, July 2014
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Title: METHODOLOGY FOR VEHICLE EMISSION IMPACTS ANALYSIS FROM SIGNAL TIMING OPTIMIZATION OF AN URBAN STREET NETWORK
Creator: Lu, Pu
Date: 2017, 2017-05
Description: The pace of urban street capacity expansion is much slower than the growth of vehicle travel, leading to several traffic congestions. To...
Show moreThe pace of urban street capacity expansion is much slower than the growth of vehicle travel, leading to several traffic congestions. To mitigate traffic congestion expanding capacity is not feasible for many cases due to the high cost and space restriction. Improving the efficient use of the available capacity becomes the solution. Traffic signal optimization is one of the most widely used ways of efficient capacity utilization. Concurrent to traffic signal optimization, more smooth traffic operations in term of reasonably higher speed and a reduced traffic delay will in turn change vehicle emissions. This research aims to quantify changes in vehicle emissions resulted from traffic signal optimization by introducing a new methodology for quantifying network wide vehicle emissions and real world application in of the Chicago urban network for validation. The proposed methodology considers undersaturation and oversaturation of traffic conditions and urban street segments with varying speeds for different types of vehicles and pollutants by hour of the day and location within the network. It begins with information collection and research through a review of existing methods for urban street network vehicle emission estimation, intersection vehicle emission evaluation, and the running vehicle emission modeling. The proposed methodology focuses on three elements: estimation of emissions from vehicles stopped at intersections and for vehicles cruising along segments, as well as analysis of network wide vehicle emissions and changes in overall network vehicle emissions by time of the day and by areas. Major steps of methodology application included the use of Chicago TRANSIMS model implementing optimized signal timing plans to obtain refined traffic volumes at intersections and on segments, increased vehicle operating speeds, changed green splits, and vehicle compositions for all intersections and segments in the urban street network, the application of an intersection vehicle emission model for stopped vehicles and a segment vehicle emission model for vehicles cruising on segments, and the network wide analysis of vehicle emission changes by vehicle type and pollutant type in a 24-hour period within an urban street network, respectively. The proposed methodology for intersection vehicle emission estimation was successfully applied to a dense urban street network in Chicago for each approach per cycle and then extended for intersections in hours of the day to analyze the impacts of traffic changes at intersections on exhaust changes. In order to develop the network vehicle emission analysis method, it is essential to evaluate the segment vehicle emissions. This is achieved by using the concept of vehicle specific power which is used to estimate emissions of cruising vehicles considered along with vehicle speeds and speed changes and hence analyzing changes in segment vehicle emissions affected by traffic volume changes derived from signal timing optimization. The decreased number of vehicles stopped at intersections by applying signal timing optimization will reduce intersection emissions, hence reducing overall network vehicle emissions. In addition to have vehicle emissions got reduced at intersections, the increasing vehicle speed for vehicles on segments could further reduce vehicle emissions on segments.
Ph.D. in Civil Engineering, May 2017
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Title: INVESTIGATING THE SIGNIFICANCE OF HALF-SATURATION COEFFICIENTS ON WASTEWATER TREATMENT PROCESSES
Creator: Shaw, Andrew Robert
Date: 2015, 2015-05
Description: This research is focused on the half-saturation coefficient (KS), which is an important, but often overlooked, parameter in the Monod equation...
Show moreThis research is focused on the half-saturation coefficient (KS), which is an important, but often overlooked, parameter in the Monod equation commonly used to describe biological wastewater treatment processes. Following an initial literature review, the research uses data for a denitrifying activated sludge process to show that KS is a function of the maximum rate and, further, that the relationship can be described either using a simple linear regression or by modeling diffusion explicitly. Building on this initial investigation of a particular treatment system, the research introduces and uses a “porter-diffusion” model that approximates diffusion to a linear equation for KS in the Monod equation. This is used to describe the linear relationship between KS and maximum rate for four different biological wastewater treatment systems. Finally, a sensitivity analysis is carried out on the parameters in the porter-diffusion model to show that r0 – a measure of cell size or diffusion distance – is the most sensitive parameter for a simple activated sludge process model based on a modified version of the International Water Association (IWA) activated sludge model #1 (ASM1). Overall this research has shown that in all of the biological wastewater treatment systems investigated in this thesis: (1) KS is not a constant but is a function of the maximum rate; (2) diffusion is a dominant mechanism that influences KS; (3) that a suitable expression for KS can be estimated using the porter-diffusion model, a linear data fit, or by modeling diffusion explicitly; and (4) measurements of KS in the laboratory must be carried out at the same food-to-microorganism (F/M) ratio as the full-scale system under investigation.
Ph.D. in Civil Engineering, May 2015
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Title: SEISMIC STUDY OF DUCTILE AND NON-DUCTILE CONCENTRICALL1 BRACED FRAMES
Creator: Sutchiewcharn, Narathip
Date: 2013, 2013-07
Description: Braced Frames, both ductile and non-ductile systems, are in high demand due to their considerable strength and attractiveness. Therefore, the...
Show moreBraced Frames, both ductile and non-ductile systems, are in high demand due to their considerable strength and attractiveness. Therefore, the better understanding of their behaviors will be beneficial, in which, is the focus in this study. With different failure modes expected based on design methodology, the study of non-ductile system is focused on connections and their contributions toward performance of frame systems, while the ductile system is concentrated on the behavior of braces itself. For non-ductile system with the model-based simulation approach, local brace connection models were developed extending from the validation with the existing specimens. Then, the extensive seismic global performances including local joints, from both local brace and gravity frame connections, are evaluated with the adaptation of collapse methodology outlined in FEMA-P695. For ductile system, with the expectation of hinges formed in braces causing by buckling, the global performances under reversal loadings, e.g. ground motions, are in jeopardy due to the strength degradation. Taking advantage of FEM simulations in addition to testing, the proposed tube-in-tube brace configuration is introduced as buckling-controlled brace (BCB). The effects of parameters are studied using analytical models. The performances observed from proposed tube-in-tube configuration are satisfied under both monotonic and cyclic loadings.
PH.D in Civil Engineering, July 2013
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Title: HEURISTIC DECISION-MAKING MODEL FOR ELECTRICAL FOREMEN WHEN WORKFLOW IS DISRUPTED
Creator: Pandey, Arjun R.
Date: 2016, 2016-05
Description: The decision-making process used by construction foremen at a job site when the workflow is disrupted was investigated in this study. The...
Show moreThe decision-making process used by construction foremen at a job site when the workflow is disrupted was investigated in this study. The foremen’s decision-making process was mapped and then modeled to a heuristic model. This study focuses on cognitive decision or psychological heuristic models. The study shows that construction foremen use a heuristic decision model in their decision-making. The capability of heuristic to yield fast decision is very useful in construction because it is common for a construction foreman to experience several disruptions during the course of a single workday. With heuristic decision-making, a work-around decision can be rapidly and effectively made following a construction site disruption. Understanding the ability of heuristics to facilitate rapid and effective decision-making will help the construction industry to save time and increase productivity. Research was conducted in order to map a decision process that foremen were using in their decision-making and to develop a model for a heuristic decision-making process. Interviews were conducted with 22 construction foremen in the electrical trade in 88 real disruption cases in order to understand how decisions were made after disruptions occurred. Interviews were subsequently conducted with 10 additional industry foremen in 10 real disruption cases to validate the data. Using this data, a heuristic decision-making model was developed. To validate this model, a survey was conducted with another 11 industry foremen. The findings indicate that construction foremen currently use a heuristic decision-making model known as “determinant decision attribute” (referred to as DDA) heuristics model. This DDA heuristic model was compared to the similar model with equal weighing and elimination by aspects (referred to as EW/EBA) to assess the performance of the heuristic. The DDA heuristic model correctly predicted, on average, 91% of the time what foremen’s decisions were as to which decision task to choose to assign or re-assign to crew members. Whereas, the EW/EBA model correctly predicted, on average, 82% of the time, the foremen’s decisions. A computer program was also developed for DDA heuristic model to help foremen expedite the process of their decision-making.
Ph.D. in Civil Engineering, May 2016
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Title: AN OVERVIEW OF INSPECTION, REHABILITATION AND MONITORING METHODS USED FOR CHICAGO’S MOVABLE BRIDGES
Creator: Jalabert, Patrick C.
Date: 2012-07-09, 2012-07
Description: Chicago is the historical birthplace of movable bridges. Earlier than any other city in the world, this Midwestern city started developing...
Show moreChicago is the historical birthplace of movable bridges. Earlier than any other city in the world, this Midwestern city started developing solutions to obstacles facing river transportation through innovations in moveable bridge design. With over forty movable bridges built, today, the city faces a major rehabilitation issue with the deterioration of these bridges. The need to assess the condition, and plan for the future sustainability of these bridges, is vital to Chicago’s economy and to the safety of thousands of people who cross the Chicago River every day. As many other cities in the world face problems with their moveable bridges, any plan by pertinent agencies to rehabilitate bridges in Chicago is expected to set standards for the rehabilitation and maintenance of moveable bridges. An overview of guidelines set forth by the American Association of State Highway and Transportation Officials (AASHTO) and procedures and/or methods adopted by local authorities to inspect, repair and reconstruct moveable bridges in Chicago, are important steps in identifying the underlying issues related to the structural condition and degradation process of the many movable bridges still in operation in Chicago. The objective of this study is to review (1) current practices for movable bridge inspection, repair and rehabilitation; and (2) actual repairs projects, conducted under the authority of the Chicago Department of Transportation’s Division of Engineering, to identify and summarize the underlying structural and/or serviceability issues that are inherent to movable bridges in Chicago. Specifically, the study is expected to highlight a number of important issues that stem from age, repeated use and factors that have caused deterioration of Chicago’s movable bridges and the type of repairs that may be needed to guarantee the future safe operation of these bridges.
M.S. in Civil Engineering, July 2012
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Title: ORGANIZATIONAL CULTURE IN SCHEDULING UNITS AND ITS EFFECTS ON CONSTRUCTION DELAY
Creator: Nayak, Shruti
Date: 2011-07-14, 2011-07
Description: n/a
M.S. in Civil Engineering, July 2011

Title: AN INVESTIGATION INTO THE SIGNIFICANCE OF LENGTH-THICKNESS RATIO IN GUSSET PLATE BEHAVIOR IN BRIDGE TRUSSES
Creator: Olechno, Patrick
Date: 2012-07-12, 2012-07
Description: n/a
M.S. in Civil Engineering, July 2012

Title: SAFETY IMPACTS OF INTERSECTION RED LIGHT ENFORCEMENT IN CITY OF CHICAGO
Creator: Lee, Yongdoo
Date: 2011-07-19, 2011-07
Description: Red light running at highway intersections has been a major safety concern in the United States because it often results in a...
Show moreRed light running at highway intersections has been a major safety concern in the United States because it often results in a disproportionally higher percentage of injuries than other type of crashes. Statistics shows that about 45 percent of red-light running crashes would cause injuries compare to 30 percent associated with other type of crashes. Over the past decade, many city and county governments in the United States have begun to deploy red-light enforcement systems aimed to reduce red-light running related crashes for the benefits of safety improvements. In particular, the city of Chicago has implemented the red-light enforcement system since 2004. As of the end of 2010, more than 200 signalized intersections have been equipped with red light enforcement devices. This research attempts to evaluate the effectiveness of red light enforcement system deployed in Chicago in reducing types of target crashes including head-on, rear-end, angle, turning, sideswipe- same direction, and sideswipe- opposite direction by fatal, injury, and property damage only (PDO) crash severity category. Data on approximately 1,000 signalized intersections are collected for the analysis. These intersections are classified as three categories: untreated intersections without signal modernization and no red light enforcement, Type I treated intersections with both signal modernization and red light enforcement, and Type II treated intersections with signal modernization only. The Empirical Bayesian (EB) approach has been employed to quantify the crash reduction effects of red light enforcement that would avoid the regression-to-mean biases in the estimation. First, data on untreated intersections are used to calibrate safety performance functions for injury, PDO, and total crashes per intersection per year. The SPFs are then used to establish the EB-adjusted crash frequencies for Type I treated intersections for the before modernization period and Type II treated intersections for the before modernization period and red light enforcement period, respectively. The EB-adjusted crashes for Type I and Type II treated intersections for the after treatment period could be established by adjusting the before and after treatment period traffic volumes accordingly. The differences between EB-adjusted crashes and field observed crashes for Type I and Type II treated intersections for the after treatment period are the effect of signal modernization and combined effect of signal modernization and red light enforcement. The difference of the two effects thus represents the pure effect of red light enforcement. The effect of red light enforcement is further assessed by differentiating the Type I and Type II treated intersections according to number of through movement lanes and annual average daily traffic (AADT) range, respectively. For all target crashes including head-on, rear-end, angle, turning, sideswipe in the same direction, and sideswipe in the opposite direction combined, red light enforcement could on average reduce fatal crashes by 4 percent to 48 percent. Red light enforcement may increase injury crashes by 16 percent and decrease injury crashes by 8 percent. Red light enforcement may increase PDO crashes by one to 10 percent. The safety impacts of red light enforcement are separately assessed for different types of target crashes. For fatal crashes, red light enforcement may reduce fatal crashes by -1.4-1.2 percent for head-on crashes, 4-19 percent for rear-end crashes, 0.3-11 percent for angle crashes, -1.2-8 percent for turning crashes, 2-8.6 percent for sideswipe crashes in the same direction, and -0.4- 1.6 percent for sideswipe crashes in the opposite direction, respectively. Red light enforcement is generally ineffective in reducing PDO crashes. For all target crashes combined, the PDO crash increases could vary between 0.6 percent and 10.1 percent. For different types of target crashes, the highest PDO crash increases range from 0.2 percent for head-on crashes to 4.4 percent for rear-end crashes. Mixed results are obtained for red light enforcement on reducing injury crashes. For all target crashes combined, the injury crash could decrease as high as up to 8.2 percent and increase by approximately 16.3 percent. For different types of target crashes, the injury crashes may reduce by 4.7 percent for rear-end crashes to increase by 8 percent for rear-end crashes.
M.S. in Civil Engineering, July 2011
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Title: INFLUENCE OF THE FREQUENCY OF LOADING ON THE PIEZO-BARKHAUSEN RESPONSE OF STEEL FOR FATIGUE LIFE ASSESSMENT
Creator: Coulibaly, Jibril
Date: 2014, 2014-07
Description: Steel can fail prematurely under repeated cyclic loading below its proportional limit (or yielding point). Provided that a certain threshold...
Show moreSteel can fail prematurely under repeated cyclic loading below its proportional limit (or yielding point). Provided that a certain threshold in the loading magnitude, known as the endurance limit, is not exceeded, the material can sustain an infinite number of cycles (N 107). Recent interests in the piezo-magnetic behavior of ferromagnetic steels have been successfully providing reliable and physical indicators of fatigue properties of the material. Cyclic mechanical strain applied to ferromagnetic steels produce abrupt variations in the magnetization of the material referred to as piezo-Barkhausen pulses. Among the many variables influencing fatigue characteristics, the influence of the frequency of loading upon the piezo-Barkhausen response of steel is investigated herein. While the amplitude of the pulses varies, the cumulative piezo-Barkhausen indicator of damage is independent of the frequency and provides a specific measure of damage for a given level of applied strain and may be a way to evaluate service life. The distribution of the dominant frequency of the observed pulses also permits one to separate the stable states of loading from those leading to fatigue failure. Further observations on the piezo-Barkhausen signals particularities have also been made to provide a greater insight on the micro mechanisms of fatigue and damage accumulation in steel.
M.S. in Civil Engineering, July 2014
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Title: LAND USE EFFECTS ON WATER QUALITY: BUILDING A FRAMEWORK FOR CHICAGO RIVER WATERSHED
Creator: Mahdi, Naila Ghidey Ismail
Date: 2012-05-09, 2012-05
Description: The purpose of this study is to introduce a framework that enables a holistic watershed approach that models the dynamics of water quality and...
Show moreThe purpose of this study is to introduce a framework that enables a holistic watershed approach that models the dynamics of water quality and landuse in a highly urbanized watershed. The landuse-water quality relationship is a complex relationship and has not been adequately addressed for highly urbanized watersheds. Factors such as inadequate urban planning, increase of impervious areas and dynamics of population growth are some of the reasons for the complex relationship. Also point sources are always easy to be identified and controlled unlike nonpoint sources such as urban storm runoff. Both quantities and transport pathways of pollutant inputs are impacted by land use in the watershed. So, examining the factors that govern the relationship between different land uses and water quality within a watershed can give insights and important information about existing and potential sources of contamination. The two backbone concepts in this study are the holistic watershed perspective and the role of historical data records as part of assessment, modeling and integration tools of the watershed framework. Analysis of the records will explain watershed conditions identifying the major problem areas and justify the modeling and post analysis procedures. Data sources are often important but data availability, heterogeneity and conformity are the main challenges in integrating these sources. This research presents an approach to integrate the watershed data in a single repository and methodologies for analyzing and assessing the watershed using data warehouse and data mining technologies. A multi-dimensional model that supports complex querying of watershed data and discovery of trends and patterns in data by incorporating 40 years worth of watershed data from different source agencies in a central repository is introduced. Also, the discipline of data driven modeling was introduced in this thesis using the developed central repository. Several regression and classification algorithms were presented and assessed for their appropriateness for predicting total nitrates using few watershed attributes. The results show acceptable prediction accuracy. Five years of water quality simulation using the multi-purpose environmental analysis system BASINS coupled with the comprehensive, conceptual, and continuous simulation watershed scale model HSPF resulted in export coefficients for level (III), detailed land use for the Chicago River watershed. The water quality simulation approach utilized in this research to generate the coefficients constitutes a new contribution to the Chicago River watershed and other highly urbanized watersheds. The continuous calibrated and validated model can be used in the investigation and analysis of different scenarios and possible future conditions, thus providing a planning tool for regulatory environmental agencies. The data driven models developed can be used as operation tool to maintain the water quality parameters especially if TMDL and WQS are developed for Chicago River Watershed. So the framework proposed for this study can be considered robust with the proposed integration, planning and operating techniques and tools. Furthermore, an optimization tool is introduced in the future work section.
Ph.D. in Environmental Engineering, May 2012
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