Digital Commons Network^™

Erodibility Of Sand-Silt-Xanthan Gum Mixtures, Edwin Kotey

Theses and Dissertations

The high frequency of earthen embankment failure recorded during floods has led to the general rule that embankments should not be overtopped. This notwithstanding, overtopping cannot be entirely avoided particularly during extreme events, such as winter storms and hurricanes. Reducing soil erodibility is thus fundamental to prevent and control disasters caused by embankment failure. Recent studies have explored the use of environmentally friendly additives, such as biopolymers, to improve soil properties. Geotechnical tests have shown that biopolymers can effectively increase soil strength, but little is known about biopolymer-treated soil resistance to erosion by flowing water. Results of flume experiments to …

B-Spline Impulse Response Functions For Transient Ssi Analysis Of Pile Foundations, Kingsley C. Ozegbe

Theses and Dissertations

The advent and consequential advancements in geotechnical earthquake engineering has made soil-structural analysis (SSI) an important component in the analysis and design of earthquake resistant structures. The filtering effects of pile foundations which reduces the seismic demand on pile-supported superstructure when they are subjected to seismic waves have been investigated and confirmed by several researchers in the last 40 years. To this end, several methods of analyzing the effects of SSI have been developed over the years. From the simplified Winkler model to the more robust finite element method (FEM) and boundary element method (BEM), researchers and structural engineers alike …

Classifying Floor Accelerations For Gait Estimation And Detection, Jean Michel Franco Lozada

Theses and Dissertations

Structural vibrations are traditionally used to learn about structural systems, such as determining the dynamic characteristics of a structure and evaluating its structural performance under certain dynamic loads. Recently, researchers have proposed the use of structural vibrations to know more about the occupants of the structure in addition to the structure itself. One example of such would be to determine when a person falls, or to identify the location of a person walking in a building. Using structural vibrations to study occupants can be directly applicable to many fields, ranging from healthcare to security applications. One powerful use of structural …

Field Implementation Of A Stereo Vision System For Rnt And Stress Measurements In Cwr, Brittany Stinson

Theses and Dissertations

The use of Continuous Welded Rail (CWR) provides many advantages to the rail industry compared to the alternatively used jointed-track segments. However, one significant disadvantage is the development of thermal stresses longitudinally in the rail, which is not of concern when expansion joints are used. This is due to CWR’s inability to release thermal expansion in the absence of joints. The Rail Neutral Temperature (RNT) is the temperature at which the rail is in a stress-free state. A desired RNT is calculated based on local climate conditions and CWR installation practices are implemented to set the desired RNT at installation. …

Coastal And Inland Flooding - From Advanced Hydrodynamics And Data-Driven Modeling To Multi-Variate Coastal Vulnerability Assessment, Ahad Hasan Tanim

Theses and Dissertations

Flood risks in coastal and inland areas have historically been underestimated and underpredicted, resulting in increased flood damage and loss of human life. Flood risk under climate change and sea level rise will disproportionately impact low-wealth and marginalized communities, as they are often located in areas with less flood protection and have limited resources to adapt to the impacts of flooding. The systematic workflow of the life cycle of FRM is frequently disengaged in the current state of flood hazard assessment with system vulnerability assessment. This research aims to improve the life cycle of FRM by incorporating flood observation, monitoring, …

Floodplain And In-Channel Sedimentation In The Bedrock Congaree River, Sc, Mahsa Ahmadpoor

Theses and Dissertations

The Congaree River planform is characterized by an abrupt increase in channel sinuosity in the downstream direction. Such a change is not typical of alluvial meandering rivers but has been observed in mixed bedrock-alluvial rivers. This motivated the first study of this dissertation, specifically designed to determine if the Congaree River is indeed a mixed bedrock-alluvial river in its low sinuosity (upstream) reach. To test this hypothesis, sonar-based measurements of channel bed and sublayer elevation were performed from Columbia to the Congaree River-Wateree River confluence. The sublayer is here defined as the first surface visible in the sonar measurements underneath …

Load Determination, Strengthening, And Behavior Study Of Prestressed Concrete Channel Bridge Girders In South Carolina, Elhussien Khaled Elbatanouny

Theses and Dissertations

The South Carolina Department of Transportation (SCDOT) is currently engaged in a multi-year effort to assess the structural integrity of its inventory of over 9,000 bridges. This assessment process is expected to result in an increase in the number of bridges that require load postings, repairs, or replacements across South Carolina. This could potentially lead to adverse economic repercussions due to restricted truck routes, bridge closures, repair work, and the need for bridge replacements. To alleviate the escalating costs associated with these challenges, it is imperative to explore methods aimed at reducing the need for load postings and bridge closures …

Field And Laboratory Characterization Of Subgrade Resilient Modulus For The Aashtoware Pavement Me, Kazi Moninul Islam

Theses and Dissertations

The new Mechanistic-Empirical Pavement Design Guide (MEPDG) uses the subgrade resilient modulus (MR) as the key input parameter to represent the subgrade soil behavior for pavement design. This research focused on field and laboratory characterization of subgrade resilient modulus assessing the effects of predicted distresses and IRI on the flexible pavement. The results of this study are presented in the form of three chapters and peer-reviewed journal manuscripts. Firstly (Chapter 3), MR was obtained indirectly from Falling Weight Deflectometer (FWD) data using a back-calculation tool (i.e., SCDOT, BAKFAA, and AASHTOWare 2017) or from empirical correlations with soil index properties. MR …

Investigation Of Discrepancies In South Carolina Traffic Collision Forms, Jackson Wegmet

Theses and Dissertations

The aim of this thesis is to improve the accuracy of information recorded in the South Carolina traffic collision forms. To accomplish this, it examines 200 forms containing information about fatal crashes in work zones between 2014 and 2020 to determine how many discrepancies exist between the written narrative and other fields. In addition to obtaining these statistics, this thesis seeks to identify factors that influence discrepancies. To test the hypothesis that crash complexity and weather influence the investigating officer’s level of processing (a theory developed by Craik and Lockhart in 1972), and consequentially his/her ability to complete the traffic …

Electric Freight Transportation System Planning And Truck Operation Optimizations, Xuanke Wu

Theses and Dissertations

The substantial demand for fossil fuel consumption is a significant contributor to greenhouse gas emissions, drawing considerable public attention to health and environmental problems. As a result, vehicle electrification is currently recognized as the most effective approach to reduce CO2 emissions from transportation. However, compared to traditional fossil fuel-powered vehicles, electric vehicles have notable disadvantages, including higher upfront purchasing price, longer recharging time, and most significantly, lower driving ranges. All these challenges can potentially result in increased overall operational costs for logistics companies. This thesis proposes a comprehensive optimization modeling framework for electric freight transportation system planning and operations with …

A Systems Approach To Design And Plan Sustainable Antifragile Infrastructure Based On Aggregate Footprint And Satisfaction, Farboud Khatami

Theses and Dissertations

The concepts of robustness and sustainability in planning and design of water and energy infrastructures have been extensively explored in previous research, primarily focusing on system reliability, environmental considerations, and economic aspects. This study aims to broaden the understanding of these concepts by offering comprehensive frameworks that capture the essence of robustness and sustainability at two distinct levels.

The first level of investigation focuses on the performance of infrastructure networks during natural disasters. Traditionally, this has been addressed using reliability, resilience, and vulnerability metrics. However, these methods rely on static, deterministic, and non-stationary data, which is inadequate when dealing with …

Impact Of Dam Height And Grain Size Distribution On Breaching Of Non-Cohesive Dams Due To Overtopping, Heather O'Donal

Theses and Dissertations

The National Inventory of Dams reports 74,400 earthen dams in the United States in 2021, of these dams approximately 27% are considered at high or significant hazard risk, that is dam failure will cause widespread damage and loss of lives. The most frequent cause of dam failure is breaching caused by overtopping. Accurate predictions of breach evolution are thus crucial to determine flood hydrographs for the safety of communities and properties at risk. Laboratory experiments were conducted on non-cohesive, compacted embankments to understand the role of dam height and sediment grain size on breaching caused by overtopping. Dam heights varied …

Cost-Effective Strengthening And Automated Inspection Of One-Way Precast Reinforced Concrete Flat Slab Bridges In South Carolina, Laxman Kc

Theses and Dissertations

In South Carolina, the South Carolina Department of Transportation (SCDOT) manages 90% of the state's inventory of 9,400 bridges built in the 1950s. With more than 30% of its bridges having been under-designed and experiencing decades of service deterioration, the implications for public safety, the economy, and the transportation system are significant. To prioritize safety and address these concerns, SCDOT is in the process of conducting thorough inspections of bridges, load ratings, and exploring cost-effective and practical methods to strengthen the bridges and reduce load postings. This study is a part of the multi-year research investigation supported by the SCDOT. …

Implementation Of A 3d Laser Profiler System Into A Non-Contacting Method For Rnt & Stress Measurements, Caio Neto Penna

Theses and Dissertations

Continuous welded rail (CWR) is susceptible to the development of internal forces in the rail due to thermal effects that can lead to track buckling. Railroads typically deal with the internal stresses in the rail through the inspection of the rail neutral temperature (RNT) which is the temperature at which the internal force is zero. The existing methods in the industry to measure RNT are contacting, destructive, disruptive to railroad operations, and ineffective. The proposed concept is a promising non-contacting, non-disruptive and reference-free technique to measure RNT and the stress state in the rail. The method is based on the …

Speckle Development And Application In Uav-Based Digital Image Correlation For Transportation Infrastructure Monitoring And Assessment, Taylor Wyatt

Theses and Dissertations

A critical aspect of civil infrastructure is structural health monitoring, of which digital image correlation (DIC) has been proven to be an effective and appropriate method. There is sufficient literature on the use of stationary DIC, but an unexplored aspect is DIC-equipped unmanned aircraft systems. It has been verified in University of South Carolina labs but has not been proved in a field environment. One of the challenges of field implementation is large scale speckle application. This work focusses on identifying and addressing challenges in bringing UAV-DIC technology from the lab to the field. This includes the development of optimized …

Load Rating Evaluation Of Deteriorated Prestressed Channel Girders, Alexander Zane Henderson

Theses and Dissertations

The South Carolina Department of Transportation (SCDOT) is conducting a multi-year effort to load rate its inventory of over 9,400 bridges. This includes many bridges that are load posted due to potential structural considerations (e.g., outdated design loads, members whose capacity is difficult to assess, structural degradation). The number of load-posted bridges in South Carolina is expected to increase significantly due to recent efforts from SCDOT to assess the current state of bridge infrastructure. It is expected that the increased scrutiny may result in more load postings, which in turn may lead to restrictions on truck routes, potential bridge closures, …

Physico-Mechanical Characterization Of Prototype Earth Block Material For Constitutive Modeling, Erika Lorena Rengifo-López

Theses and Dissertations

The comprehensive understanding and experimental characterization of the overall compressive behavior of earth masonry block materials, such as compressed and stabilized earth blocks (CSEBs), are essential for developing analytical and numerical tools to predict the mechanical response and designing earth masonry structures. Furthermore, advancing the understanding of the extent of the influence of testing parameters on the material's response, such as specimen geometry, is a critical step towards standardization.

CSEBs are produced by compressing a mixture of soil, water, and a stabilizer (e.g., Portland cement). The heterogeneity of the material accrues from the variety of soil particle morphology and potential …

Achieving Sustainability In Urban Transit And High-Occupancy Vehicle Systems Through Emerging Technologies And Operations, Ruixiao Sun

Theses and Dissertations

It is critical to reduce road transportation emissions, as it is the major source contributing to greenhouse gas emissions (GHGs) and air pollution. However, the increasing travel demand due to the rise of population and economy makes the task challenging. Mathematically, road transportation emissions can be minimized in the manner of reducing total vehicle miles traveled (VMT) and lowering vehicle emission rate. Many strategies have been proven viable for achieving transportation sustainability. For example, the total VMT can be reduced by switching low-occupancy transportation modes (i.e., driving alone) to high-occupancy transportation modes (i.e., public transit, ridesharing). The development of alternative-fuel …

Versatile And Robust Non-Iterative Coupling Algorithm For Vehicle-Structure Interaction, Arya Datta

Theses and Dissertations

The dynamic analysis of the vehicle-structure interactions can be extremely computationally expensive. A general non-iterative coupling algorithm based on the substructure approach has been presented. It retains the advantage of the substructure approach that smaller subsystems are solved instead of a large system, which is usually solved when monolithic systems are solved. However, the advantage of using this general coupling approach is that it is non-iterative in nature, instead of the substructure approach that usually uses iterative procedure. The general coupling algorithm developed has been implemented to analyze dynamic interactions between the vehicle and the structure, both in two and …

Cyclic Response And Liquidfaction Behavior Of Gravelly Soils, Pitak Ruttithivaphanich

Theses and Dissertations

Cyclic response and liquefaction behavior are soil mechanisms under earthquake conditions. The study of dynamic soil response is important to evaluate soil behaviors under dynamic loading for a wide range of strains. Soil liquefaction phenomena involving a significant reduction in the strength and stiffness of saturated cohesionless soils has caused catastrophic ground failure in numerous earthquakes. Liquefaction mostly occurs in sand, but liquefaction of gravelly soil has been observed. To date, only a few studies have focused on the liquefaction of gravelly soils; hence, research data is limited. This research aims to improve the understanding of cyclic response and liquefaction …

Oxidized Graphitic Nano-Amendment Of Cement Composites: Exploring Truly Low Concentrations And Novel Particle Morphologies, Shohana Iffat

Theses and Dissertations

Oxidized graphitic nanoparticles such as multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs), can produce enhancements in physicomechanical properties of cement composites that are relevant to structural and durability performance, provided that said nanoparticles are well dispersed in the composite. Lower-bound MWCNT concentrations are reported in the literature in the range 0.01-0.05% in weight of cement (wt%). Such concentrations may not be costeffective for practical applications and may also be excessive since they would result in a nanoparticle surface area at or above 105 m2 for 1 m3 of cement paste, or 104.5 m2 for 1 m 3 of concrete, …

The Effect Of Concrete Material Properties On Rigid Pavement Design In South Carolina, Nicolet Anne Devine

Theses and Dissertations

This thesis presents the effect of concrete material inputs on rigid pavement design in the state of South Carolina. The impact of concrete strength input parameters in the historical AASHTO pavement design method and MEPDG method is investigated using three newly constructed concrete sections, I-85 in Cherokee County, I-20 in Lexington County, and I-85 in Spartanburg County. Strength data obtained from the sections were the result of QA/QC testing provided by the SCDOT during construction, as well as from UofSC laboratory testing. The compressive strength data from these tests was correlated to the elastic modulus and modulus of rupture (which …

Classification Of Acoustic Emission Data Into Load Steps Using An Artificial Neural Network, Allen Ross

Theses and Dissertations

The average age of bridges in South Carolina is approaching 40 years, very close to the 50-year service life. Almost 11% of the bridges in South Carolina are rated as structurally deficient, greater than the national average of 7.5% (South 2021). Health monitoring is the concept that in-situ sensors can continuously monitor civil structures and send real time signals of damage. This process allows for automation and could save time and money on the inspection and load rating of bridges. Health monitoring requires sensors that provide uninterrupted data without sacrificing the functionality of the bridge. A prime candidate for this …

Coalitional Game Theory For Stormwater Management And Green Infrastructure Practices, Carly Lawyer

Theses and Dissertations

As global warming and climate Variability bring about more frequent and intense rainstorms and accelerate sea level rise, our social and built environments are at heightened risk of flood induced damages and consequent costs. This is particularly true for coastal areas, facing the coupled effects of these threats while serving as home to people, businesses, unique landscapes, and historic landmarks. Complex decisions at all levels of government and community planning stand to benefit from increased understanding of possible outcomes and pathways resulting from decentralized human behavior and decision making in the realm of water resources engineering and management. Game theory …

Computer Vision-Based Automatic Railroad Crossing Monitoring And Track Inspection, Feng Guo

Theses and Dissertations

Currently, there are many imminent challenges in the railroad infrastructure system of the United States, impacting the operation, safety, and management of railroad transportation. In this work, three major challenges which are overcrowded traffic congestion at the grade crossing, low-efficiency and accuracy on inspection of missing or broken rail track components, and dense rail surface defects without quantification, respectively are studied. The congested railroad grade crossing not only introduces significant traffic delays to travelers but also brings potential safety concerns to the first responders. However, limited studies have been devoted on developing an intelligent traffic monitoring system which is significant …

Predicting Pavement Structural Condition Using Machine Learning Methods, Nazmus Sakib Ahmed

Theses and Dissertations

State departments of transportation recognize the need to incorporate pavement structural condition in their pavement performance models and/or decision processes used to select candidate projects for preservation, rehabilitation, or reconstruction at the network level. However, pavement structural condition data are costly to obtain. To this end, this paper develops and evaluates the effectiveness of two machine learning methods, Random Forest (RF) and eXtreme Gradient Boosting (XGBoost), for predicting a flexible pavement’s structural condition. The aim is to be able to predict whether a pavement section’s structural condition is poor or not based on Annual Average Daily Traffic (AADT), truck percentage, …

Development Of A First-Generation Prototype Laboratory System For Rail Neutral Temperature Measurements, Ellie Yi-Hsien Chao

Theses and Dissertations

Modern railway tracks worldwide standardize the use of Continuous Welded Rail (CWR) due to its ability to prevent disadvantages associated with rail joints in a track. CWR is laid when the rail is free of thermal stresses, also known as Rail Neutral Temperature (RNT). RNT is controlled in the CWR installation procedure; however, over time, the temperatures deviate from the RNT. The deviation causes significant thermal stresses introduced in the longitudinal direction of the rail, leading to potential failures such as pull-apart and buckling, causing track integrity and safety of train operation. The most significant potential failure is track buckling …

Impact Of Graphene On Microstructure And Compressive Strength Of Cement Mortars Utilizing Two Different Dispersion Methods, Elhussien Khaled Elbatanouny

Theses and Dissertations

Carbon-based nanomaterials are currently used to reinforce cement-based composite materials based on their superior properties. This study investigates the mechanical property (compressive strength) of cement mortars incorporated with pristine graphene. The dosages of graphene materials used were 0.01%, 0.02%, 0.03%, and 0.04% by weight of cement. Moreover, this study compares two dispersion techniques: ultrasonication with surfactant coating and mechanical blending with surfactant coating to promote the use of graphene in cement mortars. A commonly used polycarboxylate superplasticizer Sika-Viscocrete Ultra 2100, was used as a dispersant agent (surfactant) of graphene with a surfactant to graphene weight ratio of 9 to 1. …

Identification Of Structural Signature Responses From Response Time Histories Using B-Spline Impulse Response Techniques, Shadhan Ahmed Al Kharusi

Theses and Dissertations

Structure Health Monitoring (SHM) is an essential practice for ensuring the safety of people and the structures itself. For this purpose, variety of global and local damage detection methods have been used to investigate damages. Global damage detection focus on identifying damage in early stages while local damage detection related to damage location, severity, and prediction of the remaining of the structure. Any damage in structure leads to a change to the properties and characteristics of the dynamic response.

Existing methods uses modal-based and response-based for damage detection. Both have several shortcoming associate with sensitivity of the damage and measurement …

Combined Effects Of Welding Residual Stress And Thermal Expansion In Cwr, Brennan Gedney

Theses and Dissertations

Continuously welded rail with flash-butt welded joints has become standard practice for railway construction around the world. Through the process of welding, a residual stress field develops in the joint which typically remains in the rail through its service life. Consequently, the total stress is altered locally in the presence of operation induced stresses. One such stress develops due to thermal expansion of the rail during the daily and seasonal solar radiation heating cycle. This paper seeks to ascertain the combined effects of welding residual stress with thermal expansion through computer simulations. This is aimed at two objectives: determining whether …