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Articles 15991 - 16020 of 39915

Full-Text Articles in Civil and Environmental Engineering

Evaluating The Mechanisms Of Erosion For Coarse-Grained Materials, Maureen K. Corcoran, Ghada Ellithy, Michael K. Sharp, Johannes L. Wibowo Oct 2016

Evaluating The Mechanisms Of Erosion For Coarse-Grained Materials, Maureen K. Corcoran, Ghada Ellithy, Michael K. Sharp, Johannes L. Wibowo

Publications

Efforts are currently underway by the U.S. Army Corps of Engineers (USACE) to perform a risk assessment of all dams and levees within their portfolio. The vast majority of that portfolio is earthen structures. Findings from the assessments have shown that the major risk drivers for these earth structures are related to erosion (internal and external), overtopping, poorly designed and constructed intrusions (such as pipe crossings), and other factors to a lesser degree (such as burrowing animals). Therefore, the USACE is currently investigating several of these failure modes with emphasis on internal and external erosion. This paper will highlight efforts …


Exploring Access To Portable Water And Sanitation Practices In A Post-Conflict Environment: The Case Of Gulu District, Northern Uganda, Peyton Going Oct 2016

Exploring Access To Portable Water And Sanitation Practices In A Post-Conflict Environment: The Case Of Gulu District, Northern Uganda, Peyton Going

Independent Study Project (ISP) Collection

Over the course of 30 days of fieldwork in October and November of 2016, data was collected through interviews conducted with local government officials, researchers and academics, and village community members of Gulu District.

The aim of this study was to determine the extent to which agencies have improved water and sanitation in the region. The case study of Gulu utilized in-depth interviews with key informants, focus groups, and observations, and sought to determine who the local stakeholders in water and sanitation are, the water sources and sanitation facilities available and their uses, the perception local people have about their …


Changing Trends In Wave Heights In The U.S. Mid-Atlantic Region, Hillary Lane Oct 2016

Changing Trends In Wave Heights In The U.S. Mid-Atlantic Region, Hillary Lane

Civil & Environmental Engineering Theses & Dissertations

The pace and effects of climate change are an area of constant focus for coastal engineers as evolving patterns in the atmosphere worldwide affect the oceans and coasts on a regional and global scale. Surface waves respond to changing wind patterns both locally and from propagating swell, and the difficulty in predicting future wind patterns is well-established. Expectations that climate change will result in more frequent and intense coastal storms and consequently greater wave heights in the North Atlantic are still unrealized, and recent forecasts from a variety of atmosphere-ocean coupled global climate models instead predict decreasing wave heights through …


Effects Of Surrounding Water Table On A Forested Wetland Habitat In East Coast Of Virginia, Lane Stokes Oct 2016

Effects Of Surrounding Water Table On A Forested Wetland Habitat In East Coast Of Virginia, Lane Stokes

Civil & Environmental Engineering Theses & Dissertations

Exchanges into and out of a wetland, including surface water flow, groundwater flow, and constituents in the flows, usually determine the wetland physicochemical characteristics and biodiversity. To date, of these three exchanges, groundwater flow is the least studied, particularly in the United States of America. In this thesis, field observations were conducted at a forested non-tidal wetland, located on a flat hilltop. The position of the wetland is such that groundwater outflow is the only significant exchange that could be impacted by the surrounding land use. In addition, a spatially variable steady-state model was set up to extrapolate the observations …


Longitudinal Tidal Dispersion Coefficient Estimation And Total Suspended Solids Transport Characterization In The James River, Beatriz Eugenia Patino Oct 2016

Longitudinal Tidal Dispersion Coefficient Estimation And Total Suspended Solids Transport Characterization In The James River, Beatriz Eugenia Patino

Civil & Environmental Engineering Theses & Dissertations

The longitudinal dispersion coefficient is a parameter used to evaluate the effect of cross-sectional variations on substance mixing mechanisms in estuaries influenced by tide, wind and internal density variations. Considering a two dimensional approach, this study aims at evaluating a tidal area of the lower James River at approximately 19 miles upstream from the mouth at the Chesapeake Bay, in the City of Newport News, and applies an experimental procedure based on in-situ salinity concentrations to estimate the dispersion coefficient in the area where receives a discharge from the HRSD James River Wastewater Treatment Plant, and further characterizes Total Suspended …


Dynamic Elasto-Plastic Behavior Of Steel Building Sub-Assemblage Including Cfrp Retrofitting Under Impact Load, Ali Mohammed Salih Aloosi Oct 2016

Dynamic Elasto-Plastic Behavior Of Steel Building Sub-Assemblage Including Cfrp Retrofitting Under Impact Load, Ali Mohammed Salih Aloosi

Civil & Environmental Engineering Theses & Dissertations

This dissertation presents the outcome of a theoretical and experimental study of the dynamic as well as the quasi-static elasto-plastic behavior of a steel building sub-assemblage including carbon fiber reinforced polymer (CFRP) retrofitting. The steel sub-assemblage consists of a beam-column attached to a pair of beams at its top end while its bottom end is fixed. An apparatus is constructed and used for conducting a series of experiments by applying a lateral impact load on the beam-column in the presence or absence of a static axial load. An innovative procedure for determining the shape of the forcing function caused by …


Efficient Domain Decomposition Algorithms And Applications In Transportation And Structural Engineering, Paul W. Johnson Iii Oct 2016

Efficient Domain Decomposition Algorithms And Applications In Transportation And Structural Engineering, Paul W. Johnson Iii

Civil & Environmental Engineering Theses & Dissertations

Domain decomposition is a divide-and-conquer strategy. In the first part of this dissertation, a new/simple/efficient domain decomposition partitioning algorithm is proposed to break a large domain into smaller sub-domains, in such a way as to minimize the number of system boundary nodes and to balance the work load for each sub-domain. This new domain decomposition algorithm is based on the network’s shortest path solution. Numerical results indicate that the new Shortest Distance Decomposition Algorithm outperformed the most widely used METIS algorithm in 21 out of 27 tested (transportation) examples. In the second part of this dissertation, another new/simple and highly …


Exploring Length-Based Vehicle Count Data, Byad Ahmed Oct 2016

Exploring Length-Based Vehicle Count Data, Byad Ahmed

Civil and Environmental Engineering Master's Project Reports

The development of Intelligent Transportation Systems (ITS) requires high-quality traffic information within most urban areas worldwide, and under growing pressure for improving traffic management, there has been an increasing urge to collecting and monitoring of traffic data. One of the most reliable and recommended technology for drive thru or traffic control is the loop vehicle detection system. On the Portland freeway system, new software has been installed that allows the reporting of vehicle length in bins. This research investigates the use of this data (length based) by exploring time series analyses of the vehicle counts as freight and non-freight movement.


14-06 Development Of Safety Performance Functions And Other Decision Support Tools To Assess Pedestrian And Bicycle Safety, Timothy J. Gates, Peter T. Savolainen, Steven Stapleton, Trevor Kirsch, Santosh Miraskar Sep 2016

14-06 Development Of Safety Performance Functions And Other Decision Support Tools To Assess Pedestrian And Bicycle Safety, Timothy J. Gates, Peter T. Savolainen, Steven Stapleton, Trevor Kirsch, Santosh Miraskar

Transportation Research Center Reports

A field study was performed at 40 uncontrolled midblock crosswalks and 26 signalized intersections on low-speed roadways selected from the areas surrounding three major urban college campuses across lower Michigan. An array of existing traffic control devices existed at the study sites, including various crosswalk marking strategies, along with additional treatments, such as pedestrian hybrid beacons (PHBs), rectangular rapid-flashing beacons (RRFBs) and single in-street R1-6 signs. The sites also collectively included a diverse set of roadway and traffic characteristics, including crossing widths, number of lanes, and median presence, along with vehicular, pedestrian, and bicyclist volumes. Three primary evaluations were performed …


Guidance Index For Shallow Landslide Hazard Analysis, Cheila Cullen Sep 2016

Guidance Index For Shallow Landslide Hazard Analysis, Cheila Cullen

Dissertations, Theses, and Capstone Projects

Rainfall-induced landslides are one of the most frequent hazards on slanted terrains. They lead to considerable economic losses and fatalities worldwide. Intense storms with high-intensity and long-duration rainfall have high potential to trigger rapidly moving soil masses due to changes in pore water pressure and seepage forces. Nevertheless, regardless of the intensity-duration of the rainfall, shallow landslides are influenced by antecedent soil moisture conditions. To the present day, no system exists that dynamically interrelates these two factors.

This work establishes a relationship between antecedent soil moisture and rainfall expressed in the form of a Shallow Landslide Index (SLI) at 1km …


Agenda, Hampton Roads Sea Level Rise/Flooding Adaptation Forum, Hr Adaptation Forum Sep 2016

Agenda, Hampton Roads Sea Level Rise/Flooding Adaptation Forum, Hr Adaptation Forum

September 29, 2016: Adaptive Structures and Innovative Solutions

Agenda for the Hampton Roads Sea Level Rise/Flooding Adaptation Forum on September 29, 2016 at the Hampton University Conference Room 204, the Bemis Laboratories, 713 Orchard Road, Hampton, VA.


Heat Transfer In Unsaturated Soil With Application To Borehole Thermal Energy Storage, Ali Moradi, Kathleen M. Smits, Ning Lu, John S. Mccartney Sep 2016

Heat Transfer In Unsaturated Soil With Application To Borehole Thermal Energy Storage, Ali Moradi, Kathleen M. Smits, Ning Lu, John S. Mccartney

Civil Engineering Faculty Publications - Archive

In this study, we numerically and experimentally evaluated heat transfer in soils under unsaturated conditions in the context of simulating a laboratory-scale, three-dimensional soil-borehole thermal energy storage (SBTES) system. Most previous studies assumed that soil thermal and hydraulic properties are constant and that heat transfer in soil occurs only in the form of conduction, neglecting convective and latent heat transfer. In addition, there is a lack of data from controlled experiments to validate multiphase numerical models that can be used to better study SBTES systems installed in the vadose zone. The goal of this study was to evaluate the significance …


Balancing Function And Environment Toward Sustainable Design: A Building Insulation Case Study, Celine F. Manoosingh Sep 2016

Balancing Function And Environment Toward Sustainable Design: A Building Insulation Case Study, Celine F. Manoosingh

Civil Engineering & Construction: Faculty Publications

This study utilizes a proposed sustainable design process to investigate the functional and environmental metrics associated with an alternative insulation for use in buildings. A prototype exploring the use of evacuated packets of a silica compound substituting for conventional insulation was assessed. Assessment criteria included experimental comparison of heat transfer characteristics, as compared to a control facility. Additionally, a comprehensive environmental life cycle assessment and disassembly analysis was performed. Pilot study results indicate that in the new insulation design applied to the unit, heat flux decreased by an average of 4%, and improved environmental sustainability, resulting in a savings of …


Development Of A Transition Between An Energy-Absorbing Concrete Barrier And A Rigid Concrete Butress, Tyler L. Schmidt, Ronald K. Faller, Jennifer D. Schmidt, John D. Reid, Robert W. Bielenberg, Scott Rosenbaugh Sep 2016

Development Of A Transition Between An Energy-Absorbing Concrete Barrier And A Rigid Concrete Butress, Tyler L. Schmidt, Ronald K. Faller, Jennifer D. Schmidt, John D. Reid, Robert W. Bielenberg, Scott Rosenbaugh

Nebraska Department of Transportation: Research Reports

From 2010 to 2015, MwRSF researchers developed the RESTORE barrier, which is a restorable MASH TL-4 median barrier with a steel and concrete rail supported by elastomer posts and steel skids. The research effort reported herein describes the initial development of a transition from the RESTORE barrier to a rigid TL-4 concrete buttress.

The previously-developed RESTORE barrier LS-DYNA model was validated against three full-scale vehicle crash tests. Several design concepts were generated through a series of brainstorming efforts. The primary transition concept consisted of a pin and loop connection between the RESTORE barrier and rigid concrete buttress, which was designed …


Nonparametric Liquefaction Triggering And Postliquefaction Deformations, J. S. Yazdi, Robb Moss Sep 2016

Nonparametric Liquefaction Triggering And Postliquefaction Deformations, J. S. Yazdi, Robb Moss

Civil and Environmental Engineering

This study evaluates granular liquefaction triggering case-history data using a nonparametric approach. This approach assumes no functional form in the relationship between liquefied and nonliquefied cases as measured using cone penetration test (CPT) data. From a statistical perspective, this allows for an estimate of the threshold of liquefaction triggering unbiased by prior functional forms, and also provides a platform for testing existing published methods for accuracy and precision. The resulting threshold exhibits some unique trends, which are then interpreted based on postliquefaction deformation behavior. The range of postliquefaction deformations are differentiated into three zones: (1) large deformations associated with metastable …


Pace, Clint And Linda Pace (Fa 879), Manuscripts & Folklife Archives Sep 2016

Pace, Clint And Linda Pace (Fa 879), Manuscripts & Folklife Archives

Folklife Archives Finding Aids

Finding aid only for Folklife Archives Project 879. Project titled: “Water-powered Mills in Warren County, Kentucky.” Includes history of water run mill sites in Warren County, Kentucky, mill terms, and survey sheets with brief descriptions of mills. Sheets include a brief description, informant’s name, and an illustration of the water mill.


Creep And Recovery Behavior Of Polymeric And Chemically Treated Asphalt Binders, Mohammed Ziaur Rahaman Sep 2016

Creep And Recovery Behavior Of Polymeric And Chemically Treated Asphalt Binders, Mohammed Ziaur Rahaman

Student Theses and Dissertations

For quality assurance and quality control purposes, suppliers and users of asphalt binders follow the widely used dynamic shear rheometer (DSR) test method (AASHTO T 315) to capture viscoelastic properties of polymer-modified binders (PMBs), warm mix asphalt (WMA)- and reclaimed asphalt pavement (RAP)- modified binders even though it is designed for unmodified asphalt binders. AASHTO T 315 is inadequate to characterize the aforementioned binders because of the relatively small impact of the phase angle and strain levels on the rutting and fatigue factors, respectively. The recently balloted multiple stress creep recovery (MSCR) test (AASHTO T 350) results can better relate …


Linder, Gary (Fa 953), Manuscripts & Folklife Archives Sep 2016

Linder, Gary (Fa 953), Manuscripts & Folklife Archives

Folklife Archives Finding Aids

Finding aid only for Folklife Archives Project 953. Paper titled: “White Mills.” Project includes a description and photo of White Mills village and the watermill in Hardin County, Kentucky.


Atomistic‐Scale Investigation Of Effective Stress Principle Of Saturated Porous Materials By Molecular Dynamics, Chao Zhang, Zhen Liu, Peng Deng Sep 2016

Atomistic‐Scale Investigation Of Effective Stress Principle Of Saturated Porous Materials By Molecular Dynamics, Chao Zhang, Zhen Liu, Peng Deng

Department of Civil, Environmental, and Geospatial Engineering Publications

The effective stress principle is one of the most fundamental concepts in the mechanics of porous materials. Several mathematical expressions have been proposed for this fundamental principle, leading to unsettled debates on the validity and applicability of the principle and its mathematical descriptions. Recent developments in atomistic modeling techniques make it possible to understand multiphase systems at the atomistic scale. In this paper, molecular dynamics simulation is explored as a tool to investigate the stress formulation in porous materials. A molecular dynamics framework, including molecular models of phases, interatomic potentials, initial configuration, and simulation procedure, is presented. Numerical simulations based …


15-04 Travel Behavior Of Blind Individuals Before And After Receiving Orientation And Mobility Training, Dae Shik Kim, C. Scott Smith, Elyse Connors Sep 2016

15-04 Travel Behavior Of Blind Individuals Before And After Receiving Orientation And Mobility Training, Dae Shik Kim, C. Scott Smith, Elyse Connors

Transportation Research Center Reports

In this pilot study, we devised, tested, and refined a protocol for evaluating the travel behavior of blind individuals. Preliminary analyses of our pilot study data suggest that our new method involving Global Positioning Systems (GPS), accelerometers, and Geographic Information Systems (GIS), will enable us to collect objective, quantitative, and valid measures of blind individuals’ travel behavior and Orientation and Mobility (O&M) training’s effectiveness. Preliminary analysis results from a small sample of blind travelers describe the individuals’ trip distances, trip frequencies, trip destinations, trip modes, travel times, whether assisted or not, and perceived ability to get around. With the completion …


Environmental Efficiency Assessment Of U.S. Transport Sector: A Slack-Based Data Envelopment Analysis Approach, Yong Shin Park, Siew Hoon Lim, Gokhan Egilmez, Joseph Szmerekovsky Sep 2016

Environmental Efficiency Assessment Of U.S. Transport Sector: A Slack-Based Data Envelopment Analysis Approach, Yong Shin Park, Siew Hoon Lim, Gokhan Egilmez, Joseph Szmerekovsky

Mechanical and Industrial Engineering Faculty Publications

Sustainable transportation in the U.S. is essential for long-term economic growth and mobility, and environmental preservation. Using a non-radial slack-based measurement data envelopment analysis (SBM-DEA) model and state-level data, this study assesses the environmental efficiency of the transportation sector in the U.S. from years 2004 to 2012. In addition to environmental efficiency, carbon efficiency and potential carbon reduction were estimated for the 50 U.S. states. The findings of this study reveal that U.S. transportation sector was environmentally inefficient; U.S. states had an average transportation environmental efficiency score below 0.64. Therefore the states could substantially reduce carbon emissions to improve the …


The Economic Boom, Bust And Transport Inequity In Suburban Dublin, Ireland, Sarah Rock, Aoife Ahern, Brian Caulfield Sep 2016

The Economic Boom, Bust And Transport Inequity In Suburban Dublin, Ireland, Sarah Rock, Aoife Ahern, Brian Caulfield

Articles

This paper examines the existence and extent of transport inequity and disadvantage in new suburbs in Dublin, built during the Celtic Tiger period and as experienced during the recession. Findings are presented from a household postal survey from three case study areas built between 2001 and 2008. The case study areas are typical 'middle class' suburbs, and were constructed at a time when Ireland was experiencing unprecedented economic growth. The subsequent recession left many of these areas in significant negative equity, and householders with very limited housing mobility. Results from the survey point to considerable problems that are impacting on …


Public Transport Accessibility Levels For Ahmedabad, India, Jay S. Shah, Bhargav Adhvaryu Sep 2016

Public Transport Accessibility Levels For Ahmedabad, India, Jay S. Shah, Bhargav Adhvaryu

Journal of Public Transportation

Public transport plays an important role in a city’s economy and its social equity. It is also instrumental in reducing automobile dependence and traffic congestion. Several factors must come together to achieve well-functioning public transport systems. One major factor is the level of accessibility offered by the public transport system. To better understand and consequentially enhance accessibility, we must be able to measure it and map it, which is the key aim of this paper.

The methodology in this study, which was originally developed by the London Borough of Hammersmith and Fulham and later adopted by Transport for London (TfL) …


Public Transport Crowding Valuation: Evidence From College Students In Guangzhou, Jianrong Liu, Huiying Wen Sep 2016

Public Transport Crowding Valuation: Evidence From College Students In Guangzhou, Jianrong Liu, Huiying Wen

Journal of Public Transportation

Overcrowding has grown to be an increasingly important issue for public transit in Guangzhou, China. To capture traveler benefits of reduced crowding from improved public transport, it is necessary to identify the relevant importance of crowding to travelers. This paper analyzes the disutility of crowding in metro car and bus transit with discrete choice models. Based on the stated preference survey data from college students in Guangzhou, the results show that there is non-negligible impact of crowding on passenger travel. The relationship between the disutility of crowding and standee density is not linear; that is, the disutility increases at a …


Cross-Elasticities In Frequencies And Ridership For Urban Local Routes, Joseph Totten, David Levinson Sep 2016

Cross-Elasticities In Frequencies And Ridership For Urban Local Routes, Joseph Totten, David Levinson

Journal of Public Transportation

Observational data from the Minneapolis-Saint Paul region’s Metro Transit were analyzed to determine the effects of service levels on ridership levels at different intervals. The research compares changes in service levels and ridership in several service intervals and includes elasticities and cross elasticities, or the influence that these service levels have on different service intervals’ ridership. These cross-elasticities were found to have little effect during the week; however, weekend ridership was found to be influenced by rush-hour and overnight frequencies.


Effects Of Speed, Curves, And Driver Behavior On Passive Securement Systems On Large Transit Buses, Andrea Mather, Katharine Hunter-Zaworski Sep 2016

Effects Of Speed, Curves, And Driver Behavior On Passive Securement Systems On Large Transit Buses, Andrea Mather, Katharine Hunter-Zaworski

Journal of Public Transportation

Wheeled mobility devices that are not secured properly on large transit vehicles pose risks to all passengers. The purpose of this study was to increase the understanding of the effects of horizontal and vertical curves, speed, and driver behavior on the safety and security of people using wheeled mobility devices in rear-facing passive containment systems on large transit buses. Testing included the use of manual wheelchairs and lightweight scooters on an articulated low-floor transit bus. The project conclusions were derived from data produced by accelerometers placed on the bus as well as visual observations of wheeled mobility device movement. The …


Evaluation Of Horizontal Equity Under A Distance-Based Transit Fare Structure, Milad Bandegani, Meisam Akbarzadeh Sep 2016

Evaluation Of Horizontal Equity Under A Distance-Based Transit Fare Structure, Milad Bandegani, Meisam Akbarzadeh

Journal of Public Transportation

Horizontal equity requires equal distribution of investment/benefit/costs among equal members of society. In other words, a transit passenger should pay as much as he/she uses. This study evaluated the measure of fulfillment of this rule in a case study, developed a distance-based fare structure, and shows that justice is better served by switching to the proposed structure. Fare elasticity of demand and probability distribution of transit passenger trip lengths were investigated through a field survey. Although mainly used in the measurement of inequality in income or wealth, the Gini index and the recovery ratio (revenue to cost for each transit …


Modeling Transit Users Stop Choice Behavior: Do Travelers Strategize?, Mohammad Nurul Hassan, Taha Hossein Rashidi, S. Travis Waller, Neema Nassir, Mark Hickman Sep 2016

Modeling Transit Users Stop Choice Behavior: Do Travelers Strategize?, Mohammad Nurul Hassan, Taha Hossein Rashidi, S. Travis Waller, Neema Nassir, Mark Hickman

Journal of Public Transportation

Transit choice research focuses predominantly on mode choice and route choice, whereas very few studies on stop choice are conducted. To fill this gap, this research aimed to study transit stop choice behavior with a focus on how people strategize when making their choices. It is hypothesized that travelers treat stops differently based on various schemes (strategies); minimizing travel time, access time, and the number of transfers are the schemes considered in this study, and the effectiveness of several discrete choice model specifications was examined. The study found that path attributes and stop attributes have significant impacts on stop selection …


Modeling Bus Dwell Time And Time Lost Serving Stop In China, Chao Wang, Zhirui Ye, Yuan Wang, Yueru Xu, Wei Wang Sep 2016

Modeling Bus Dwell Time And Time Lost Serving Stop In China, Chao Wang, Zhirui Ye, Yuan Wang, Yueru Xu, Wei Wang

Journal of Public Transportation

The primary objective of this study was to develop a quantitative approach to estimate bus dwell time and time lost serving stop, which included acceleration and deceleration time, dead time, and time for serving boarding and alighting passengers. A polynomial model incorporating kinematics of a particle was derived for estimating bus acceleration and deceleration time. In addition, descriptive statistics methods were used to analyze dead time. A case study was conducted to show the applicability of the proposed model with data collected from the seven most common types of bus stops in China. R-square and Mean Absolute Percentage Error (MAPE) …


Transportation System Vulnerability And Resilience To Extreme Weather Events And Other Natural Hazards: Report For Pilot Project — Kytc District 1, Benjamin L. Blandford, Scott Schurman, Candice Y. Wallace, Sarah M. Mccormack Sep 2016

Transportation System Vulnerability And Resilience To Extreme Weather Events And Other Natural Hazards: Report For Pilot Project — Kytc District 1, Benjamin L. Blandford, Scott Schurman, Candice Y. Wallace, Sarah M. Mccormack

Kentucky Transportation Center Research Report

This research’s objective is to assist the Kentucky Transportation Cabinet (KYTC) in its efforts to develop strategies to address natural hazard vulnerabilities and improve the resiliency of Kentucky’s transportation infrastructure. Recent federal legislation calls for state transportation agencies to develop a risk-based asset management plan for National Highway System (NHS) assets that includes consideration of natural hazards. Similarly, the Federal Highway Administration (FHWA) calls for state transportation agencies to identify potential vulnerabilities associated with extreme weather events and climate change, and to incorporate these findings into transportation planning, design, and maintenance practices.