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2011

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Articles 301 - 324 of 324

Full-Text Articles in Civil Engineering

Safety Evaluation Of Roadway Lighting Illuminance Levels And Its Relationship With Nighttime Crash Injury Severity For West Central Florida Region, Enrique Gonzalez-Velez Jan 2011

Safety Evaluation Of Roadway Lighting Illuminance Levels And Its Relationship With Nighttime Crash Injury Severity For West Central Florida Region, Enrique Gonzalez-Velez

USF Tampa Graduate Theses and Dissertations

The main role of roadway lighting is to produce quick, accurate and comfortable visibility during nighttime conditions. It is commonly known that good lighting levels enable motorists, pedestrians and bicyclists to obtain necessary visual information in an effective and efficient manner. Many previous studies also proved that roadway lighting minimizes the likelihood of crashes by providing better visibility for roadway users.

Appropriate and adequate roadway lighting illuminance levels for each roadway classification and pedestrian areas are essential to provide safe and comfortable usage. These levels are usually provided by national, or local standards and guidelines. The Florida Department of Transportation …


Estimation Of Pedestrian Safety At Intersections Using Simulation And Surrogate Safety Measures, Nithin K. Agarwal Jan 2011

Estimation Of Pedestrian Safety At Intersections Using Simulation And Surrogate Safety Measures, Nithin K. Agarwal

University of Kentucky Doctoral Dissertations

With the number of vehicles increasing in the system every day, many statewide policies across the United States aim to increase the use of non- motorized transportation modes. This could have safety implications because the interaction between motorists and non-motorists could increase and potentially increasing pedestrian-vehicle crashes. Few models that predict the number of pedestrian crashes are not sensitive to site-specific conditions or intersection designs that may influence pedestrian crashes. Moreover, traditional statistical modeling techniques rely extensively on the sparsely available pedestrian crash database.

This study focused on overcoming these limitations by developing models that quantify potential interactions between pedestrians …


Modeling Extreme Traffic Loading On Bridges Using Kernel Density Estimators, Cathal Leahy, Eugene J. Obrien, Bernard Enright Jan 2011

Modeling Extreme Traffic Loading On Bridges Using Kernel Density Estimators, Cathal Leahy, Eugene J. Obrien, Bernard Enright

Conference papers

Kernel density estimators are a non-parametric method of estimating the probability density function of sample data. In this paper, the method is applied to find characteristic maximum daily truck weights on highway bridges. The results are then compared with the conventional approach


Design Mentoring Tool, Bob Mccullouch, Walter Land Jan 2011

Design Mentoring Tool, Bob Mccullouch, Walter Land

JTRP Technical Reports

In 2004 a design engineer on-line mentoring tool was developed and implemented The purpose of the tool was to assist senior engineers mentoring new engineers to the INDOT design process and improve their technical competency. This approach saves senior engineers time while developing a consistent mentoring approach and standardizing technical knowledge in road and bridge design. It is a self-guided tool that utilizes multi-media and web-based technologies, trains engineers in the design process and provides resources to use for developing plans and specifications. Available resources include INDOT design practices, design standards, design memos, specification and construction standards, procedures, and check …


Impact Of Signal Timing Information On Safety And Efficiency Of Signalized Intersections, Anuj Sharma Jan 2011

Impact Of Signal Timing Information On Safety And Efficiency Of Signalized Intersections, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

Signalized intersections are provided in traffic networks to improve the safety and efficiency of vehicular and pedestrian movement. There are various measures under education, enforcement and engineering headings that are being attempted to improve safety and efficiency of operations at a signalized intersection. Provision of signal countdown timer, a timer showing the remaining red and green time in a phase, is one such measure and is commonly adopted in India. However, studies on effects of countdown timer under Indian traffic conditions are very scarce. Traffic heterogeneity and lack of lane discipline makes transferability of models developed in other countries (with …


Role Of Information On Probability Of Traffic Conflict On The Onset Of Yellow, Nathaniel P. Burnett, Anuj Sharma Jan 2011

Role Of Information On Probability Of Traffic Conflict On The Onset Of Yellow, Nathaniel P. Burnett, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

This paper examines the effect of information provided to drivers through advance warning flashers (AWFs) on driver’s probability of conflict at the onset of yellow at a high-speed intersection. AWFs are specifically designed to minimize the number of vehicles trapped in their respective dilemma zones at the onset of yellow. A probit modeling technique was used to establish dilemma zone boundaries. Based on the dilemma zone boundaries probability of a perceived conflict curves was computed and compared against actual conflicts observed at each of the studied intersections. The comparison between the actual and theoretical probability of conflict curves generated a …


Role Of Information On Probability Of Traffic Conflict On The Onset Of Yellow, Nathaniel P. Burnett, Anuj Sharma Jan 2011

Role Of Information On Probability Of Traffic Conflict On The Onset Of Yellow, Nathaniel P. Burnett, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

This paper examines the effect of information provided to drivers through advance warning flashers (AWFs) on driver’s probability of conflict at the onset of yellow at a high-speed intersection. AWFs are specifically designed to minimize the number of vehicles trapped in their respective dilemma zones at the onset of yellow. A probit modeling technique was used to establish dilemma zone boundaries. Based on the dilemma zone boundaries probability of a perceived conflict curves was computed and compared against actual conflicts observed at each of the studied intersections. The comparison between the actual and theoretical probability of conflict curves generated a …


Bs News January/February Jan 2011

Bs News January/February

Building Services Engineering

No abstract provided.


The Effect Of Loose Mix Aging On The Performance Properties Of Warm Asphalts, Thomas Martin Clements Jan 2011

The Effect Of Loose Mix Aging On The Performance Properties Of Warm Asphalts, Thomas Martin Clements

University of Kentucky Master's Theses

Recent improvements in warm mix asphalt technologies have spurred an aggressive adoption of these new practices within the asphalt paving industry. Concerns have arisen among federal and state agencies about the effects of this line of products on the performance of asphalt pavements. An investigation of the effects of lowering mixing, aging and compactions temperatures while varying the loose mix aging time was performed. Hamburg Wheel Tracking, Flow Number, Dynamic Modulus and Fracture Energy testing were used to evaluate mechanistic properties of the materials.


Particulate Organic Carbon Fate And Transport In A Lowland, Temperate Watershed, William Isaac Ford Iii Jan 2011

Particulate Organic Carbon Fate And Transport In A Lowland, Temperate Watershed, William Isaac Ford Iii

University of Kentucky Master's Theses

Small lowland agricultural systems promote conditions where benthic biological communities can thrive. These biogeochemical processes have significant impacts on terrestrial ecosystem processes including POC flux and fate, nutrient balances, water quality budges, and aquatic biological functioning. Limited information is available on coupled biological and hydrologic processes in fluvial systems. This study investigates the mixture of biological and hydrologic processes in the benthic layer in order to understand POC cycling in the South Elkhorn system. Further, comprehensive modeling of POC flux in lowland systems has not been performed previously and the behavior of potentially controlling variables, such as hydrologic forcing and …


Micropile Response To Combined Loading, Kyle Allen Kershaw Jan 2011

Micropile Response To Combined Loading, Kyle Allen Kershaw

Doctoral Dissertations

"The familiarity and acceptance of micropiles by engineers, contractors, and owners has greatly expanded in recent years such that they are routinely considered on many projects. However, research regarding the behavior of micropiles has lagged behind. The goal of this research project was to address some of the fundamental gaps that were not addressed in engineering practice and require further study and testing. Specifically, this research studied the behavior of micropile foundations subjected to simultaneous axial and lateral (combined) loading, including an assessment of the impact of axial load on lateral behavior of micropiles. This research project consisted of three …


Development And Testing Of Chemically-Based Self-Consolidating Concrete, Mark Daniel Ezzell Jan 2011

Development And Testing Of Chemically-Based Self-Consolidating Concrete, Mark Daniel Ezzell

Masters Theses

"Self-consolidating concrete (SCC) possesses several characteristics that can benefit the concrete construction industry including accelerated construction, a reduction in labor and equipment, and a reduction in construction noise through eliminating or reducing the need to vibrate the concrete. However, SCC has some potential downsides. These problems can usually be attributed to higher paste content, higher fines content, rounder aggregate, and higher water to cement (w/c) ratios used to increase the flow of the concrete. The goal of this research project was to develop a SCC that had improved material properties through the use of chemical admixtures instead of modifications to …


Leaching Characteristics Of Inorganic Contaminants From Coal Fly Ash, Tingzhi Su Jan 2011

Leaching Characteristics Of Inorganic Contaminants From Coal Fly Ash, Tingzhi Su

Doctoral Dissertations

"Leaching of trace elements raises environmental concerns in coal fly ash disposal and reuse. US EPA is in the process of creating the first national rule on coal ash management. However, due to the complexity of coal fly ash composition, the leaching characteristics of trace elements are not well understood. Meanwhile, driven by the tightening emission regulations, new types of coal fly ashes are continuously generated as a result of the technological evolution at coal energy industry. The changing landscape highlights the needs for a comprehensive database to assess the leaching characteristics of different types of coal fly ashes, evaluation …


Hilbert Transform Applications In Signal Analysis And Non-Parametric Identification Of Linear And Nonlinear Systems, Zuocai Wang Jan 2011

Hilbert Transform Applications In Signal Analysis And Non-Parametric Identification Of Linear And Nonlinear Systems, Zuocai Wang

Doctoral Dissertations

"Hilbert Huang Transform faces several challenges in dealing with closely-spaced frequency components, short-time and weak disturbances, and interrelationships between two time-varying modes of nonlinear vibration due to its mixed mode problem associated with empirical mode decomposition (EMD). To address these challenges, analytical mode decomposition (AMD) based on Hilbert Transform is proposed and developed for an adaptive data analysis of both stationary and non-stationary responses. With a suite of predetermined bisecting frequencies, AMD can analytically extract the individual components of a structural response between any two bisecting frequencies and function like an adaptive bandpass filter that can deal with frequency-modulated responses …


Postcyclic Behavior Of Low-Plasticity Silt, Shuying Wang Jan 2011

Postcyclic Behavior Of Low-Plasticity Silt, Shuying Wang

Doctoral Dissertations

"Liquefaction of low-plasticity silt has been reported during earthquakes in the recent past. Excess pore pressure builds up due to the dynamic loading and then dissipates. The postcyclic behavior of low-plasticity silt was investigated in this research for materials obtained from the Mississippi River Valley. The experimental program involved specimen preparation using a slurry consolidation approach. A special technique was developed for specimen movement, reducing the testing program time by half. Both static and cyclic triaxial tests were conducted to confirm the ability to prepare replica specimens. In order to characterize the monotonic behavior, triaxial tests were conducted to determine …


Influence Of Particle Size And Specimen Preparation On The Iowa Pore Index, Christopher Paul Davis Jan 2011

Influence Of Particle Size And Specimen Preparation On The Iowa Pore Index, Christopher Paul Davis

Masters Theses

"This study was performed in order to identify a size correction that would allow aggregate of different sizes, other than the standard 1/2-3/4-inch fraction, to be used in the Iowa Pore Index (IPI) test. This size correction would allow for the IPI to be determined for aggregate gradations of material that have a nominal maximum size (NMS) smaller than 3/4-inch. The interest in a size correction for the IPI developed from its use in a Durability Factor (DF) estimation equation. The estimation equation was developed with the use of 19 different DF from Missouri aggregate sources, where eight aggregates had …


Categorization And Experimental Evaluation Of Anchorage Systems For Fiber-Reinforced Polymer Laminates Bonded To Reinforced Concrete Structures, Stephen V. Grelle Jan 2011

Categorization And Experimental Evaluation Of Anchorage Systems For Fiber-Reinforced Polymer Laminates Bonded To Reinforced Concrete Structures, Stephen V. Grelle

Masters Theses

"While externally-bonded fiber-reinforced polymer (FRP) composites are commonly used for the strengthening of structurally deficient reinforced concrete (RC) members, the topic of anchoring FRP to concrete to achieve higher design strengths has not been addressed. Many innovative systems have been developed to anchor FRP to concrete, but the research involving these anchorage systems is not centralized and is therefore difficult to access. Additionally, systematic testing procedures for evaluating the strength of an anchorage system have not been widely used. To aid in the organization of anchorage system research and facilitate a better understanding of anchorage system behavior, a categorization system …


Robust Statistical Methods For Non-Normal Quality Assurance Data Analysis In Transportation Projects, Mohammad Moin Uddin Jan 2011

Robust Statistical Methods For Non-Normal Quality Assurance Data Analysis In Transportation Projects, Mohammad Moin Uddin

University of Kentucky Doctoral Dissertations

The American Association of Highway and Transportation Officials (AASHTO) and Federal Highway Administration (FHWA) require the use of the statistically based quality assurance (QA) specifications for construction materials. As a result, many of the state highway agencies (SHAs) have implemented the use of a QA specification for highway construction. For these statistically based QA specifications, quality characteristics of most construction materials are assumed normally distributed, however, the normality assumption can be violated in several forms. Distribution of data can be skewed, kurtosis induced, or bimodal. If the process shows evidence of a significant departure from normality, then the quality measures …


Steel Beams Strengthened With Ultra High Modulus Cfrp Laminates, Nisal Abheetha Peiris Jan 2011

Steel Beams Strengthened With Ultra High Modulus Cfrp Laminates, Nisal Abheetha Peiris

University of Kentucky Doctoral Dissertations

Advanced composites have become one of the most popular methods of repairing and/or strengthening civil infrastructure in the past couple of decades. While the use of Fiber Reinforced Polymer laminates and sheets for the repair and strengthening of reinforced concrete structures is well established, research on the application of FRP composites to steel structures has been limited. The use of FRP material for the repair and rehabilitation of steel members has numerous benefits over the traditional methods of bolting or welding of steel plates. Carbon FRPs (CFRPs) have been preferred over other FRP material for strengthening of steel structures since …


Monitoring And Improving The Effectiveness Of Quality Control And Quality Assurance In Road Construction At Al-Ain Municipality, Mohammed Muftah Sultan Al Aryani Jan 2011

Monitoring And Improving The Effectiveness Of Quality Control And Quality Assurance In Road Construction At Al-Ain Municipality, Mohammed Muftah Sultan Al Aryani

Theses

A good roads network has an important bearing on the economic growth of the country. Construction of quality roads, which is considered a primary objective of any highway agencies and contractors, requires concerted efforts on many fronts. Over the past several years, agencies have been working with the construction industry to implement Quality Assurance/Quality Control activities (QA/QC) in an effort to improve the quality of highway construction. They are used as a mean to describe the materials, workmanship, and other general requirements for the project that the highway agencies expect from the contractors. Good specifications should be easy to understand …


Selection Of Source And Use Of Traffic Information In Emergency Situations, R. Michael Robinson, Asad Khattak Jan 2011

Selection Of Source And Use Of Traffic Information In Emergency Situations, R. Michael Robinson, Asad Khattak

VMASC Publications

The access and the use of advanced traveler information systems (ATISs) by drivers during normal commuting have been extensively assessed and analyzed. Emergency managers and transportation officials have extended the results of studies of ATIS use under routine conditions to emergency scenarios under the assumption that drivers' responses to information under emergency conditions mimic those seen under normal driving conditions. A recent survey of potential hurricane evacuees suggests the need to revisit this assumption. Results indicate that although commercial radio reports and variable message signs continue to be the sources of traffic information cited the most frequently, other information sources …


Adaptation Of Low Impact Design To The Desert Southwest, Abubaker Ali Alamailes Jan 2011

Adaptation Of Low Impact Design To The Desert Southwest, Abubaker Ali Alamailes

Open Access Theses & Dissertations

A low Impact Development (LID) practices were used to design an Integrated Management Practices (IMP) system for a residential lot .The design was adapted to the Desert Southwest region based on twenty years of climate data including precipitation and temperature for three representative cities: El Paso, TX, Albuquerque, NM, and Phoenix, AZ. In order to capture stormwater runoff close to its source and to provide as much stored water as possible for plants, LID practices including bioretention cells and vegetated swales were applied throughout the lawn. The purpose of the design is to maintain the pre-development hydrologic characteristics of the …


Evaluation Methods For Health Monitoring Of Aerospace Structure Rotary Joints, Sergio Armando Navarro Jan 2011

Evaluation Methods For Health Monitoring Of Aerospace Structure Rotary Joints, Sergio Armando Navarro

Open Access Theses & Dissertations

In September 2007, the excessive vibrations played a significant role in the station operation since one of the rotary joints, which provides the station electrical energy, presented an anomaly. The replacement of its bearing components and re-lubrication were necessary to reduce the problem. To avoid a new anomaly, the inspection of the rotary joints performance continues by using the accelerometers data. This thesis presents three new approaches to monitor the vibrations at the International Space Station based on Root-Mean-Square, kurtosis, and Approximate Entropy (ApEn). MATLAB functions and codes were necessary to implement the three monitoring techniques results from the provided …


Strategies To Improve And Preserve Flexible Pavements At Intersections, Imad N. Abdallah Jan 2011

Strategies To Improve And Preserve Flexible Pavements At Intersections, Imad N. Abdallah

Open Access Theses & Dissertations

Many rural intersections originally constructed with thin untreated flexible base and hot mix or a two-course surface treatment experience severe pushing, shoving and rutting. These failures cause an extremely rough surface that can cause damage to small vehicles and potentially cause motorists to lose control of their vehicle. These distresses almost always result in complete failure of the existing pavement that must be repaired several times during the life of the roadway by maintenance forces. Pavement sections constructed with the same materials adjacent to the intersection perform adequately until the approach (approximately 150 ft in advance) of the intersection and …