Civil Engineering Commons^™

Alternative Funding Mechanisms For State Transportation Systems In Predominantly Rural States, John E. Anderson, Eric Thompson

Bureau of Business Research Publications

The Transportation Research Board of the National Academies has identified a number of research needs related to alternative transportation finance systems. Alternatives are needed because motor fuels taxes are proving to be insufficient to fund operation and maintenance costs of the transportation system. The long-term trend is likely to be continuing use of motor fuel taxes, supplemented by, or transitioning to, use-based fees. Current research in progress in this area is focused on designing variable fees that will internalize congestion externalities in urban areas. These approaches are particularly well suited to highly urbanized areas, but other approaches may be required …

Sustainable Public Transportation In Large Cities: Demand Estimation, Tadeas Umlauf

Open Access Theses & Dissertations

Public transportation helps to decrease the negative externalities caused by people's mobility. In many countries, the total number of vehicles and traffic has risen many times in the last decades but there is limited space to improve infrastructure in the cities. Large cities all over the world have a lot of issues with congestion, traffic noise, emission of greenhouse gases, and accidents. According to many international examples, sustainable public transportation in combination with synergistic projects (park & ride, kiss & ride, bike & ride) can help to overcome these issues. Therefore new transit modes and routes have been implemented in …

Water Recovery From Silica Saturated Ro Concentrate By The Concentrate Enhanced Reverse Osmosis Process, Gautam Patwardhan

Open Access Theses & Dissertations

Membrane fouling due to silica precipitation during reverse osmosis (RO) continues to be documented as the most common challenge in attaining stable continuous operation of RO systems across water treatment plants (1). Silica scale precipitation is time dependent and involves multiple steps leading to aqueous polymerization, condensation of polymers to form colloids, and deposition onto a solid surface (2). Exceeding the solubility of silica, widely considered to be in the range of 100-140 ppm, under a pH of 8 at 25 °C by various researchers, results in the precipitation of silica on the membranes, thereby limiting water recovery. Once the …

Transformation Of, In, And By Learning In A Service-Learning Faculty Fellows Program, Mary Cazzell, Shirley Theriot, Joan M. Blakey, Melanie L. Sattler

Civil Engineering Faculty Publications - Archive

Transformative learning is the most desired core outcome in adult education. The qualitative study examined critical reflections for professional transformation related to development and implementation of service-learning courses or projects from four university faculty members during enrollment in a Service-Learning Faculty Fellows program and post-servicelearning implementation. Reflective questions related to faculty perceptions of student learning, service-learning as pedagogy, and their own learning— transformation of, in, and by learning, respectively. Content analyses of faculty reflections resulted in three categories of transformation based on three preservice-learning and three post-servicelearning descriptive themes: (1) transformation of student learning from anticipatory integration to conflicts between …

Investigation Of An Association Between Childhood Leukemia Incidences And Airports In Texas, Sala. Nanyanzi Senkayi, Melanie L. Sattler, Nancy Rowe, Victoria Chen

Civil Engineering Faculty Publications - Archive

As worldwide demand for air travel increases, emissions from airports will likely also increase. Airport emissions pose a concern due to lack of information about their quantity and impacts on human health and the environment. This research aimed to address the question of whether there is an association between childhood leukemia cases and airport emissions in Texas. Rather than looking at the impacts of a single airport on the surrounding community, this study looks at all airports in the state of Texas, and 2 134 incidences of childhood leukemia (children age 9 and under) state–wide over a 10–year period. The …

Effect Of Enhanced Leachate Recirculated (Elr) Landfill Operation And Gas Extraction On Greenhouse Gas Emission, Sonia Samir

Civil Engineering Dissertations - Archive

The bioreactor/ enhanced leachate recirculated (ELR) landfill operation with the addition of moisture/ leachate to the landfill, accelerate the process of landfill waste decomposition; and increase the generation of LFG over a shorter period of time. Since emissions from the landfills are directly related to the gas generation, the increase in gas generation might also increase the emission from the landfill. On the contrary, the presence of gas extraction is suggested to mitigate the fugitive emissions from the landfills. Therefore, the motivation of the current study was to evaluate the effect of ELR operation as well as the gas extraction …

Estimation Of Optimum Compaction Level For Bioreactor Landfill Operation, Dipak Tiwari

Civil Engineering Dissertations - Archive

The effect of compaction on the degradation of MSW is important for the successful operation of bioreactor landfill. It has been a general tendency to compact working face solid waste as much as possible to gain more space. Previous studies has shown moisture content, moisture recirculation and ambient temperature were important components for degradation. There was a limitation on the compaction effect on degradation. Although several studies were conducted in the past to find the hydraulic conductivity of the waste, there was lack of work to find the optimum compaction to achieve sufficient flow inside the landfill and thus to …

Spatial Variability Models And Prediction Analysis Of Soil Properties Using Geostatistics, Tejo Vikash Bheemasetti

Civil Engineering Dissertations - Archive

Soils are composed of solid, water and air phases whose characteristics are highly variable. The interactions of these phases in the soil matrix can lead to different types of topographical formations and characteristics. Due to the uncertainty and complex interactions among these phases, studies on soils have always been a challenging problem for engineers. These variations and uncertainties make it necessary for engineers to adopt new techniques and methods to analyze soil properties in order to determine or interpret their generalized behaviors and patterns. Existing research in variability analysis tends to focus on the distribution of the soil properties, reliability-based …

Evaluation Of Lightweight Geofoam For Mitigating Bridge Approach Slab Settlements, Pinit Ruttanaporamakul

Civil Engineering Dissertations - Archive

The bump at the end of a bridge infrastructure is one of the frequent problems found in Texas and other states. Transportation agencies spend millions of dollars annually to repair the bump problem. The major cause of the problem is the settlement of backfill materials and foundation soils, as well as the erosion of backfill. Research was undertaken at the University of Texas at Arlington to study the embankment located on US 67 over SH 174 in Johnson County, Cleburne, Texas. The embankment was reconstructed, replacing the top of existing fill soil with lightweight EPS 22 geofoam blocks to reduce …

Response Of Unsaturated Silty Sand Over A Wider Range Of Suction States Using A Novel Double-Walled Triaxial Testing System, Ujwalkumar Dashrath Patil

Civil Engineering Dissertations - Archive

In recent decades, the state-of-the-art of our understanding of unsaturated soil performance has been considerably enhanced by incorporating novel and advanced features to the conventional testing devices such as direct shear device, ring shear device, triaxial device and true triaxial device. The novel suction-controlled triaxial system used in this research is fully automated and has enhanced features such as volume change device and double-walled cell to monitor the volume change accurately during all the stages of unsaturated triaxial test. Despite the sophistication, such devices can help in testing mechanical behavior of unsaturated soils only up to matric suction (s) value …

Numerical Modeling Of Ground Movements Associated With Trenchless Box Jacking Technique, Babak Haji Mohammad Hasan Mamaqani

Civil Engineering Dissertations - Archive

The Trenchless Technology (TT) is defined as a family of methods used to install, renew, replace or renovate new pipe/box or existing pipe/box underground with little or no surface disruption. TT is divided into two main categories including Trenchless Construction Methods (TCMs) and Trenchless Renewal Methods (TRMs). TCMs are used to install new utilities and pipes underground while TRMs are used to renew, renovate and replace an existing utility or pipe. Box jacking (BJ) is a TCM used to install rectangular box culverts under existing facilities such as highways and railroads. In this method, box culverts are pushed through the …

A Unified Bond Theory, Probabilistic Meso-Scale Modeling, And Experimental Validation Of Deformed Steel Rebar In Normal Strength Concrete, Chenglin Wu

Doctoral Dissertations

"Bond between deformed rebar and concrete is affected by rebar deformation pattern, concrete properties, concrete confinement, and rebar-concrete interfacial properties. Two distinct groups of bond models were traditionally developed based on the dominant effects of concrete splitting and near-interface shear-off failures. Their accuracy highly depended upon the test data sets selected in analysis and calibration. In this study, a unified bond model is proposed and developed based on an analogy to the indentation problem around the rib front of deformed rebar. This mechanics-based model can take into account the combined effect of concrete splitting and interface shear-off failures, resulting in …

Plant Uptake Of Environmental Contaminants: Applications In Phytoscreening, Matthew Alan Limmer

Doctoral Dissertations

"Plants interact directly with their surroundings, extracting nutrients and water from the subsurface to support growth and development of the plant. Through the roots, plants also exude and uptake numerous chemicals. Many of the pathways can also be used by environmental contaminants to be translocated to above ground plant tissues. Such uptake of contaminants has proven useful in remediation and phytoscreening - the use of plants to delineate contaminant plumes. Sampling of trees at contaminated field sites has been used to identify areas of groundwater contaminated with a variety of chlorinated solvents. The use of plants as contaminant biosensors requires …

Seismic Repair Of Bridge Columns With Interlocking Spirals And Fractured Bars, Yang Yang

Doctoral Dissertations

"During earthquakes, reinforced concrete (RC) bridge columns may experience different levels of damage such as cracking, spalling, or crushing of concrete and yielding, buckling, or fracture of reinforcing bars. This study developed and assessed permanent and emergency methods to repair damaged bridge columns with fractured longitudinal reinforcement through experimental and modeling work. The permanent repair method involved replacement of the plastic hinge region by removal of spirals, replacement of longitudinal bar segments by mechanically splicing with new bars segments attached with mechanical couplers, replacement of concrete, and installation of an externally bonded carbon fiber reinforced polymer (CFRP) jacket. The emergency …

Mechanical And Transport Properties Of Alkali-Activated Natural Pozzolans As Sustainable Binders, Brittany Radke

Calvert Undergraduate Research Awards

OPC production accounts for 5 to 7% of the global carbon dioxide (CO₂) emissions, contributing to global warming. The desire to reduce CO₂ emissions and produce more durable concrete has given impetus to search for new binders. It is suggested that alkali-activated natural pozzolans have the potential for use as a sustainable replacement for OPC in concrete.

The current study presented herein evaluated fresh, mechanical, and transport properties of alkali-activated natural pozzolan mortars containing various concentrations of sodium hydroxide solutions as an alkaline activator. To this aim, alkali-activated natural pozzolan mortars were made with concentrations of sodium …

Concession Analysis For Highway Infrastructure Projects Financed As Public-Private Partnerships, Tanaphat Jeerangsuwan

Open Access Dissertations

Public funds allocated to the improvement and maintenance of highway infrastructure have reached the limits due to a rapid rate of socioeconomic growth and deterioration in infrastructure system performance. A public-private partnership (PPP) concessions a contractual and project financing mechanism that helps public authorities lessen the impact of their limited financial resources. In this project financing scheme, a public authority enters into a partnership with a private concessionaire for the purpose of developing a specific infrastructure facility. In return, the concessionaire receives the right to operate for a specified period of time. This creates strong potential for the delivery of …

Methods For Estimating Sediment Yield And Dam Capacity In The Great Lakes Watershed, Jennifer Hui

Wayne State University Theses

Sedimentation is the most important factor in the longevity of dams built in the United States. As most dams are reaching their capacity for sediment storage, this study investigated the historical and predicted future rates of sediment accumulation as well as the remaining storage capacity. This study examined the mechanisms influencing sediment production and storage in the watershed to provide future insight regarding potential control of this process. Twelve reservoirs throughout the Great Lakes watershed were selected and analyzed for their greater applicability to the entire watershed. Both historic and new data were collected on these dams to determine how …

Measurements Of Fluvial Sediments Using A Single-Frequency Acoustic Attenuation System, Thomas Alexander Kajdan

Electronic Theses and Dissertations

Suspended sediments are a global-scale pollutant that threaten the integrity of our waterways and pose an environmental threat to many aquatic ecosystems. Innovative techniques are required to continuously monitor this pollutant. Ultrasonic acoustic measurements have the potential to improve the temporal resolution of fluvial sediment data. This work investigates the use of a prototype field grade single-frequency acoustic attenuation system that was developed at the National Center for Physical Acoustics (NCPA), located at the University of Mississippi. This field-deployable unit consists of two 20 MHz immersion transducers that are aligned in a "pitch-catch" configuration at a fixed distance of 18 …

Effect Of Construction Worker Demographic On E-Learning With Hazard Communication Standard, Serhan Kaya

Wayne State University Theses

Construction safety and health training can be delivered by different training methods, such as traditional, online and blended learning. E-learning is a newly introduced method whose effectiveness is still being investigated. This study focuses on the effect of construction worker demographics on the effectiveness of e-learning. The univariate analysis technique was used to find out the distribution and frequency of data collected by an internet based system. Further, multivariate analysis (cross tabulation) and analysis of variance (ANOVA) were performed to determine the association between the independent variables which are age, gender, ethnic background, union status, number of employees in the …

Wider Dissemination Of Household Travel Survey Data Using Geographical Perturbation Methods, Kelly J. Clifton, Steven R. Gehrke

Civil and Environmental Engineering Faculty Publications and Presentations

Public agencies spend vast amounts of money collecting information about passenger travel in household travel surveys. These data are valuable for the rich and detailed information they provide, which contribute to regional and statewide travel demand models. These data have utility beyond travel demand modeling in their application to transportation policy and travel behavior research. As the demand on these data increase, so have the quantity of information collected. Detailed geospatial referencing of the home, work and other travel destinations are common practice and permit the integration with other spatially archived data sources, such as land use characteristics, transportation system …