Engineering Commons^™

Liquefaction Potential Of South Carolina Coastal Plain Soils Using Dilatometer Data, Joseph Ronald Williamson

Theses and Dissertations

In recent years much research has been focused on developing the flat plate dilatometer (DMT) as a tool to estimate the liquefaction potential of soils. Currently the DMT is over shadowed by the more accepted methods of estimating liquefaction potential which utilize test data from either the standard penetration test (SPT), cone penetration test (CPT), or shear wave velocity test (Vs). The SPT, CPT, and V_s tests are all well-developed methods of estimating liquefaction potential and are supported by extensive databases; however, the DMT is believed by many researchers to be the superior alternative. Due to the DMT's minimal …

Assessing Corrosion Damage In Post -Tensioned Concrete Structures Using Acoustic Emission & A Preliminary Investigation Of Biopolymer Doped Cement Mortar For Use In Structural Restoration, Aditya Appalla

Theses and Dissertations

A sizeable portion of the civil infrastructure is made from concrete. An estimate shows that about 7 billion cubic meters of concrete is made annually worldwide. With the deterioration of the infrastructure due to aging or external factors, significant monetary and technological investment is needed for condition evaluation, maintenance and repair. Two areas that account for a considerable portion of this investment are condition evaluation for maintenance of corroded concrete structures and mortar patching for repair and rehabilitation.

The primary method of evaluation of a structure is by visual inspection. But this method is limited as some crucial areas in …

Syntactic And Semantic Interoperability Among Hydrologic Models, Mostafa Mohamed Elag

Theses and Dissertations

Development of integrated hydrologic models requires coupling of multidisciplinary, independent models and collaboration between different scientific communities. Component-based modeling provides an approach for the integration of models from different disciplines. A key advantage of component-based modeling is that it allows components to be created, tested, reused, extended, and maintained by a large group of model developers and end users. One significant challenge that must be addressed in creating an integrated hydrologic model using a component-based approach is enhancing the interoperability of components between different modeling communities and frameworks. The major goal of this work is to advance the integration of …

Investigation Of Longitudinal Joints Between Precast Prestressed Deck Bulb Tee Girders Using Latex Modified Concrete, Clark Baer

Theses and Dissertations

This study investigates the behavior and performance of latex modified concrete (LMC) as a closure pour material with a U-bar connection detail in longitudinal joints between precast deck bulb tee bridge girders with integral concrete decks. The objective was to determine if the joint detail was capable of resisting service shear and moment stresses as well as eliminate the formation of cracks in the joint during fatigue loading. This study tested two large scale reinforced concrete slab specimens measuring 6 ft x 6 ft x 8 in joined together by the longitudinal joint detail in fatigue flexure shear loading. The …

Selection And Clustering For Disease Associated Genetic Variants, Yubo Zou

Theses and Dissertations

Epigenetics is the study of chemical reactions, which are orchestrated for the development and maintenance of an organism. Genetic or epigenetic variants (GEVs) encompass different types of genetic measures, such as Deoxyribonucleic acid (DNA) methylation at different CpG sites, expression level of genes, or single nucleotide polymorphisms (SNPs). With the development of technology, huge amount of genetic and epigenetic information is produced. However, the rich information potentially brings in challenges in data analyses. Thus it is necessary to reduce the dimension of data to improve efficiency. In my dissertation, I will focus on two directions of dimension reduction: variable selection …

A Model Experiment To Assess The Effects Of Inclusions On Wave Propagation In Soil Media, Thomas Houston

Theses and Dissertations

The research described involved analyzing and characterizing changes to propagating surface waves that are caused by items embedded in a half-space consisting of a soil medium. Numerical and experimentally obtained data of three-dimensional surface wave responses to dynamic impulse loading were examined. Results from this research are compared to changes to surface waves observed in previous investigations that were caused by the presence of voids and inclusions embedded in an elastic half space. The focus of this work was to identify whether the characteristic responses identified in previous studies, based substantially on analytical and finite element analyses results, can be …

Experimental Study On Piping Failure Of Earthen Levee And Dams, Yusuf Ahmed Sharif

Theses and Dissertations

Piping in an earthen levee, one of the main causes of failure, is a complex phenomenon. Most of the available research on piping failure has been on non-cohesive sandy soils. Jet Erosion Test and Hole Erosion Test have been conducted to study piping failure in an indirect manner. However, no general purpose formula is presently available to describe the erosion process due to complex erosion characteristics of cohesive soils in earthen levees.

Experimental investigations in a flume to understand the piping erosion process in an earthen levee are conducted in this research. One of the sidewalls and the bottom of …

Experimental Investigation Of Steady Flows At A Breached Levee, Cyrus K. Riahi-Nezhad

Theses and Dissertations

Steady flow at a breached levee is studied in this dissertation through a generalized model and a case study. The generalized experimental set-up consists of a main channel with an opening in its side wall and an adjustable sluice gate at its downstream end. Water surface elevation and the three-dimensional velocity field are measured by a point gauge and an Acoustic Doppler Velocimeter (ADV), respectively. Time-averaged measured values of velocity field and free surface elevation are presented. In addition, Froude Number, turbulent kinetic energy (TKE) and bed shear stress are computed from the measured results. Results show that the flow …

Impact Of Curing Time And Curing Stress On The Mechanical Behavior Of Cement-Improved And Cement-Fiber-Improved Soft Soil, Ryan Daniel Starcher

Theses and Dissertations

In order to improve the engineering properties of soft soils, materials, such as cement and fiber, can be introduced to the soil mass. Currently, design criterion for a cement-soil mixture requires only the measurement of unconfined compressive strength. This simple measurement may not be adequate to describe the behavior that results from differing field loading conditions. A series of consolidation tests and unconfined compression tests were conducted with special attention being paid to the effects of curing time and vertical curing stress. It is shown that the introduction of cement into soft soils results in decreased compressibility and increased unconfined …

Removal Of Synthetic Organic Compounds And Nom By Single-Walled Carbon Nanotubes-Ultrafiltration And Forward Osmosis Membrane System, Jiyong Heo

Theses and Dissertations

This overall theme of this dissertation is to investigate the potential engineered application of low pressure membranes incorporated with single-walled carbon nanotubes (SWNTs) and forward osmosis (FO) membrane systems for the removal of synthetic organic compounds (SOCs) and natural organic matter (NOM) from drinking water sources. The focus is on the use of SWNTs-ultrafiltration (UF) and FO membrane systems to facilitate the removal of these compounds and potential applications of these membrane system designs for reducing the energy demands and membrane fouling in environmental water filtration process and seawater desalination. The SWNTs-UF results indicate that SOCs transport is influenced by …

Acoustic Emission Source Characterization Of Fatigue Crack Extension In Steel Bridge Material, Md Mozahid Hossain

Theses and Dissertations

The probability of Acoustic Emission (AE) detection associated with fatigue crack extension in steel bridge components is a difficult problem due to the complexity of the AE sources. AE is a very promising technique for structural health monitoring and automated micro-crack detection as it is generated by the material itself, unlike other nondestructive testing techniques (for example impact echo and ultrasonics), which require external input sources. Characterizing the source of AE is an ongoing challenge because AE sensors are not only sensitive to the AE signals but also to mechanical noise and reflections. It is therefore difficult to interpret the …

Quantifying Regional-Scale Water Storage Using Models And Observations: Application For Drought Assessment In South Carolina, Mirza Md Mozaddid Billah

Theses and Dissertations

Hydrologic models are widely used to determine the occurrence and severity of droughts, and to aid in the decision making process for reducing drought impacts. These models apply approaches including water and energy balance equations to determine water availability at field to continental scales. One challenge in implementing hydrologic models at larger scales (regional to continental) is the lack of data with sufficient spatial and temporal resolution to represent actual conditions within the modeling domain. If such data is available, the challenge remains how best to find, access, and process the data so that it can be used within hydrologic …

Application Of Agent-Based Approaches To Enhance Container Terminal Operations, Omor Sharif Abul Bashar Mohammad

Theses and Dissertations

Queuing at marine terminal gates has long been identified as a source of emissions and high drayage costs due to the large number of trucks idling. The first study in this dissertation addresses queuing of trucks at marine terminal gates and presents a novel agent-based framework where the drayage companies can minimize congestion by using the provided real-time gate queuing information. The problem was tackled based on the approach of El Farol Bar problem from game theory. Our proposed model can be used as a means of managing demand for the marine terminals, assuming that drayage firms will adjust their …

Structural Health Monitoring Of Concrete Systems, Matthew Kelly Jones

Theses and Dissertations

Concrete material is widely used around the world for the construction of many infrastructure including highway bridges, residential and commercial building, dams, electric power generation plants, and nuclear power plants. It is therefore practical to continue development of both improved structural systems as well as innovative condition assessment techniques for new and existing concrete structures. This thesis includes two studies which focus on structural health monitoring of concrete systems. The first project deals with performance assessment of an in-situ precast approach slab system and the second is an investigation of acoustic emission (AE) as a condition assessment technique for alkali-silica …

Assessment Of Damage In Concrete Structures Using Acoustic Emission, Marwa Abdelrahman

Theses and Dissertations

Evaluating the integrity of concrete structures is an essential procedure to ensure structural safety and durability. Non-destructive testing (NDT) is needed for localizing and characterizing the growing damage in existing structures and also for quality control of new structures. Visual inspection is a commonly used method; however it is not suitable for early detection of damage and very dependent on the experience of the inspector. More research is needed to establish advanced methods for structural health diagnosis such as acoustic emission (AE). Acoustic emission is notably sensitive to active damage in concrete structures. This thesis includes three studies that mainly …