Civil Engineering Commons^™

Damage Evaluation Of Concrete Structures Using Acoustic Emission, Rafal Anay

Theses and Dissertations

The deterioration and aging of the infrastructure in the U.S. have become a crucial issue, especially for highway bridges and nuclear power plants. The reliability and safety of existing structures are affected by growing populations and limited resources. This issue has gained significant concern during the last two decades and efforts are being conducted to accelerate the improvement of nondestructive testing (NDT) and structural health monitoring (SHM) methods. Additional information regarding the condition of existing structures and the early detection of damage can aid in reducing overall maintenance costs. The studies presented in this dissertation employ acoustic emission (AE) as …

Health Monitoring Of Liquid Pipelines, Mohammed Hameed Sabhan Al-Tofan

Theses and Dissertations

The crude and refined oil, water, and other liquids are widely transported through pipelines over long distances within geographical boundaries of countries or beyond. Pipeline accidents, however, are frequent, affecting operation and reducing targeted performance. The frequency of these accidents presents a growing concern and necessitates the need for an effective health monitoring plan. This plan requires monitoring of flow conditions and warning of any changes or abnormal conditions. Abnormalities in the flow conditions include changes in the piping system performance due to defects, such as leaks and blockages. These changes can be located and quantified utilizing different approaches. Two …

Development Of Models For Road-Rail Intermodal Freight Network Under Uncertainty, Md Majbah Uddin

Theses and Dissertations

Freight activities are directly related to a country’s Gross Domestic Product and economic viability. In recent years, the U.S. transportation system supports a growing volume of freight, and it is anticipated that this trend will continue in the coming years. To support the projected increase in freight volume, an efficient, reliable, and low-cost freight logistics system is necessary to keep the U.S. competitive in the global market. In addition, intermodal transport is becoming an increasingly attractive alternative to shippers, and this trend is likely to continue as state and federal agencies are considering policies to induce a freight modal shift …

Mechanisms Of Radium Adsorption On Silica And Barite, Hamid Hamid

Theses and Dissertations

The use of experimental studies with computer modeling is vital in the development of cost-effective methods for treating radium containing wastewaters. The goal of this dissertation is to develop a multi-scale model to study radium removal mechanisms onto silica and barite, and the effect of water quality parameters on radium removal. The major tasks to be accomplished in this study are: to develop a multi-component isotherm model for radium removal on different ionized silica surfaces; to re-parameterize sulphate force fields to account for metal-sulfate interactions; and to simulate radium removal on barite under different water quality conditions. We conducted molecular …

Numerical Modeling Of Submarine Minibasin Flow And Morphodynamics, Elena Bastianon

Theses and Dissertations

Intraslope basins, or minibasins, are important morphological features of the continental slope in both modern and ancient sedimentary systems. Minibasins have an elliptical or spherical shape with a steep inlet or proximal zone followed by an almost horizontal basin floor, and an overflow zone near the downstream basin lip. These basins are filled with sediment transported by successive events of turbidity currents and other types of submarine flows. The work presented here focuses on turbidity current sedimentation in intraslope minibasins, which is often described in terms of the ‘fill-and- spill’ conceptual model. The ‘fill-and-spill’ model has been used previously to …

Characterization Of The Spatial And Temporal Changes In River Geometry And Sand Load With Field Data Analysis And 1d Numerical Modeling, Zeyad Ayoob Sulaiman

Theses and Dissertations

The quantification of the changes in channel geometry and sand load that have occurred on the Missouri River after engineering works and that characterize the Altamaha River in the fluvial-tidal transition zone is the main objective of this research. Dam construction and channelization on the Missouri River resulted in flow regulation, sediment shortage by dam reservoir trapping, channel straightening and narrowing. Quantifying the morphodynamic response of the Lower Missouri River to these engineering projects at short and long-time scales is a difficult problem that we approach with the analysis of the available field data and with the aid of a …

The Restoration Of The Nile River And Its Delta, Egypt. Numerical Modeling, Basim Mohammed Naseef Al-Zaidi

Theses and Dissertations

The construction of the High Aswan Dam significantly reduced the flood flows and the sediment supply to the Egyptian portion of the Nile River. Consequences of this changes in river hydrology are diffuse channel bed erosion in the upstream part of the river, in- channel sedimentation in the downstream part of the system, delta recession, habitat deterioration, wetlands loss, water pollution, and environmental problems. The feasibility of a Nile River-Delta restoration project with controlled flow releases and sediment augmentations at Aswan is here investigated with the aid of site-specific one-dimensional morphodynamic models. The water source for the restoration project, based …

Hydrothermal Carbonization Of Food Waste For Nutrient Recovery And Reuse, Ifeolu M. Idowu

Theses and Dissertations

Food waste represents a rather large and currently underutilized source of potentially available and reusable nutrients. Laboratory-scale experiments evaluating the hydrothermal carbonization of food wastes collected from restaurants were conducted to understand how changes in feedstock composition and carbonization process conditions influence primary and secondary nutrient fate. Results from this work indicate that at all evaluated reaction times and temperatures, the majority of nitrogen, calcium, and magnesium remain integrated within the solid-phase, while the majority of potassium and sodium reside in the liquid-phase. The fate of phosphorus is dependent on reaction times and temperatures, with solid-phase integration increasing with higher …

Understanding Geopolymerization Process For Enhancement Of Mechanical Properties Of Fly Ash Based-Geopolymer Concrete, Lateef Najeh Assi

Theses and Dissertations

Concrete is a major construction material that is largely made up of cement. Unfortunately, the manufacturing process for the cement currently used to produce concrete releases a great deal of CO2, which endangers the environment. Hence, finding alternatives to ordinary Portland cement is of extreme importance. The intellectual contribution of this dissertation is the development of an improved understanding of the geopolymerization process so that the compressive strength of cement can be maximized while the need for external heating is minimized. The intent is to create a substance to replace commonly used cement without sacrificing other beneficial properties. The first …

Assessing Exposure To Occupants In An Indoor Space Due To Expirated Aerosols: Application Of Computational Fluid Dynamics, Firoza Binte Omar

Theses and Dissertations

Indoor environment is an important issue for the well-being of the society. In the United States more than 90% people spend their time indoor, indoor air pollution is more culpable than the pollution outside air. Two third of US businesses lose more than $100,000 per year due to workplace related illness. The trend of sharing the work space has an impact on total sick leaves in a company. Infectious particles released by a flu sufferer’s sneezing, coughing or even laughing can be a vital source. A thorough analysis on infectious particles’ transmission and air flow of the space can provide …

Impact Of Critical Path Method (Cpm) Of Scheduling On On-Time Completion Of Transportation Projects, Fahim Ahmed

Theses and Dissertations

This study addresses the effectiveness of Critical Path Method (CPM) scheduling on project delivery. Specifically, the on-time completion of projects with and without a CPM schedule is explored. The paper uses data from 2,097 South Carolina transportation projects let after February 2008 and substantially completed by August 2015. The delay analysis uses the original contract completion date as well as the completion date adjusted by change orders. Chi-Squared tests are used to examine the relationship between CPM scheduled projects and delayed projects, and t-tests are used to compare the mean delay (in days) between CPM scheduled and unscheduled projects. The …

Evaluation Of Sonocatalytic Degradation Of Ibuprofen And Sulfamethoxazole In The Presence Of Various Catalysts, Yasir Alhamadani

Theses and Dissertations

Over the last two decades, large quantities of products, such as medicines, disinfectants, and personal care products, have been released into surface waters and wastewater treatment facilities by the pharmaceutical and chemical industries which have come to the attention of scientists with regard to their impacts on life in lakes, rivers, and groundwater. Among various types of treatment processes, ultrasonic (US) treatment process was used in this study to investigate the effect catalysts and removal of selected pharmaceutical’s (PhACs) compounds (ibuprofen (IBP) and sulfamethoxazole (SMX)). Carbon nanomaterials (CNMs) have become candidates for numerous applications in nanocomposites, microelectric devices, sensors, energy …

Acoustic Emission Detection In 304h Stainless Steel Due To Intergranular Stress Corrosion Cracking, Joseph W. Hill

Theses and Dissertations

Storage of spent nuclear fuel has become problematic in past decades due to delayed completion of long-term repositories for various reasons. Temporary storage containers called Dry Cask Storage Systems (DCSS) made of stainless-steel and surrounded by reinforced concrete have been in use but are exceeding their designed usage periods. Defects in canisters can be exacerbated in climates susceptible to high humidity and salinity levels. As inspection and relicensing of DCSS increases, more efficient monitoring techniques could save nuclear facilities valuable time and resources. Crack detection of the canister walls or welds in real time may be possible utilizing acoustic emission …

Probabilistic Multilevel Constitutive Model Of The Compressive Strength Of Hardened Cement Paste Reinforced With Mwcnts, Yohanna Mejia Cruz

Theses and Dissertations

Constitutive models available in the literature typically describe the compressive strength of ordinary Portland cement paste (OPC) in a deterministic fashion, in some cases as a function of variables such as W/C, porosity, and the clinker chemical composition. The significant effect of the proportion of W/C on the final strength, porosity and density have been reported in several works in material science. Some studies have shown that the addition of MWCNTs can also modify the microstructure of cement significantly, and improve compressive strength and other mechanical and physical properties. In principle, W/C, MWCNTs addition, porosity, density, and compressive strength are …

Meso-Scale Simulation Of Size-Dependent Shear Behavior In Glass Fiber Reinforced Polymer Reinforced Concrete Beams Without Stirrups, Sina Khodaie

Theses and Dissertations

There is extensive experimental evidence of the decrease in the shear stress at failure at increasing effective depths in concrete beams reinforced with glass fiberreinforced polymer (GFRP) bars without shear reinforcement. An important practical implication is that extrapolating strength values from typical laboratory-scaled experiments to design larger members may be misleading. The complexity of the underlying mechanics is reflected in the difficulty of using commercially available numerical tools to accurately estimate shear strength irrespective of beam size. This dissertation presents research on a Lattice Discrete Particle Model (LDPM) based model to simulate the response of scaled slender GFRP reinforced concrete …

Development Of Models And Solution Methods For Different Drayage Applications, Samaneh Shiri

Theses and Dissertations

In the last decades, intermodal freight transport is becoming more attractive in the global supply chains and freight transport policy makings. Intermodal freight transport provides a cost-effective, reliable, and efficient movement of freight by utilizing the strengths of different transport modes. The initial and final segment of intermodal freight transport, performed by truck, is known as “drayage.” The scheduling of truck movements in drayage operation within the service area of an intermodal terminal is an operational problem which leads to a truck scheduling problem that determines the efficient schedule of trucks while satisfying all transportation demands and constraints. Drayage accounts …

Nondestructive Evaluation Of Corrosion Damage In Reinforced Concrete Aged Slab Specimen, Rawya Abdulsattar Abduljabbar

Theses and Dissertations

The deterioration of concrete bridge decks presents a maintenance challenge for most transportation agencies and bridge owners. This problem increases during the freeze-thaw cycle. De-icing salts can accelerate the deterioration process. Corrosion of steel reinforcement in reinforced concrete structures is considered a dominant factor causing premature deterioration, especially those structures located in a coastal environment. The resulting corrosion product produced has several times the volume of steel, resulting in cracking of the concrete cover if the corrosion is significant. In this study, a bridge deck specimen was subjected to an artificial environment to accelerate the corrosion process. Prior to this …

Computations Of The Dynamic Fracture Of Plane Structures By The Extended Finite Element Method, Iman Asareh

Theses and Dissertations

Finite element methods for the simulation of dynamic fracture in plane structures are presented. The method is a modified extended finite element method (XFEM) for dynamic fracture simulations with a new methodology to construct the XFEM basis functions for discontinuities. In contrast to conventional XFEM in which the extended interpolation is defined to only capture the discontinuities, the proposed method describes the enrichment functions so that they reproduce both the discontinuities and the polynomial bases of sufficiently high order which are critical for finite element convergence. Such enrichment functions, by adopting the Duffy’s transformation, can be simply defined in terms …

Children's Law Center Site Redevelopment, Caroline Olivia Haggard, Javonte Isaac, Joshua Joslin, E'Lexus Nelson, Ana Vieira, Adrien Williams, David Zalla

Senior Theses

Soda City Engineering and Consulting was contracted by the USC School of Law to redevelop the Children’s Law Center site in Columbia, SC. Currently, the site does not comply with current standards and specifications. The objective of this project is to completely redevelop the site with a new annex building and ensuring everything is up to code, while still allowing the historic structure to maintain its use throughout construction.

Low-Cost Fishing Net-Reinforced Cement Matrix Overlay For Substandard Concrete Masonry In Coastal Areas, Mohammed A. Mousa

Theses and Dissertations

The aim of this project is to investigate a novel and affordable option to externally strengthen substandard concrete masonry (CM) walls for out-of-plane loads (e.g., high winds and flying debris). Two types of strengthening materials for fiber-reinforced cement mortar (FRCM) overlays are investigated; namely, fishing net (FN) and welded wire steel mesh (WWSM) reinforcements.

Salient mechanical properties of representative materials including substandard concrete masonry unit (CMU) blocks, mortar, nylon FN and WWSM reinforcements, and FRCM composite, were experimentally characterized. A simple bilinear model is proposed to describe the tensile behavior of the FRCM composite. An analytical model was then used …

Reducing Model Selection Computational Cost By Metamodeling The Evidence, Ramin Madarshahian

Theses and Dissertations

Modeling is an abstraction of reality that lets a designer or engineer perform simulations with a “real” object or structure without testing it physically. However, the result of simulations is as good as their models. Selecting the best model among many candidates is another challenge.

Complex models could translate into more accurate predictions, but they also require larger computational effort. The Bayes factor is often used to compare different models considering the data and analyst’s experience. To obtain the Bayes factor, the Bayesian model evidence is calculated; however, calculating the Bayesian model evidence of computationally expensive models is not a …

Investigating The Feedstock Properties And Process Conditions Influencing The Characteristics Of Products Generated From The Hydrothermal Carbonization Of Organic Feedstocks, Liang Li

Theses and Dissertations

Hydrothermal carbonization (HTC) is a novel environmentally beneficial thermal conversion process for the transformation of organic feedstocks to value-added products. However, little is known about the role of feedstock properties and/or process conditions during carbonization. This study was conducted to determine the parameters most influential during the HTC of organic feedstocks. Experiments and statistical analyses were conducted to: (1) determine the effect of specific feedstocks, feedstock interactions, and process conditions on carbonization product characteristics; (2) understand how initial liquid characteristics influence product characteristics and evaluate the significance of these initial liquid characteristics in predicting product characteristics; and (3) develop statistical …

Characterization Of Subgrade Resilient Modulus For Mepdg And The Effects On Pavement Rutting, Md Mostaqur Rahman

Theses and Dissertations

In 2008, the American Association of State Highway and Transportation Officials (AASHTO) released a modified pavement design method (i.e., the Mechanistic Empirical Pavement Design Guide (MEPDG)) based on Long Term Pavement Performance (LTPP) data from all over the United States. The MEPDG default design parameters developed from the LTPP database are expected to be significantly different than those for South Carolina material, traffic and weather conditions, thus the default design parameters may not be accurate for South Carolina. Therefore, the new pavement design method should be calibrated for South Carolina conditions by performing MEPDG local calibration.

Different input variables should …

Performance Assessment Of Hsrm Concrete Ties Through Finite Element Model Simulations, Adam I. Zeitouni

Theses and Dissertations

Concrete ties have become a promising alternative to timber ties for freight lines with increased curvature, high annual traffic, and large axle loads. They are also widely adopted in passenger lines. High strength (HS) concrete is the material of choice in the fabrication of prestressed concrete railroad ties. The higher strength of the concrete is directly related to higher values of the Elastic Modulus, thus increasing the rigidity of the material. The combination of increased strength, rigidity, and the material brittleness may lead to the development of high amplitude stresses with high gradients, which appears to be a common underlying …

Intermodal Network Design And Expansion For Freight Transportation, Fateme Fotuhiardakani

Theses and Dissertations

Over the last 50 years, international trade has grown considerably, and this growth has strained the global supply chains and their underlying support infrastructures. Consequently, shippers and receivers have to look for more efficient ways to transport their goods. In recent years, intermodal transport is becoming an increasingly attractive alternative to shippers, and this trend is likely to continue as governmental agencies are considering policies to induce a freight modal shift from road to intermodal to alleviate highway congestion and emissions. Intermodal freight transport involves using more than one mode, and thus, it is a more complex transport process. The …

Confluence Of Density Currents Produced By Lock-Exchange, Hassan Ismail

Theses and Dissertations

Density currents represent a broad classification of flows driven by the force of gravity acting on a fluid with variable density. With examples of density currents including turbidity currents, sand storms, salt wedges in tidal rivers, and oil spills, a great deal of attention has been previously given to understanding the underlying mechanisms of such flows and implications of those flows on fluid, species, and sediment transport. Although documented confluences occur naturally in terrestrial and submarine settings,little attention has been given to understanding the confluence of two density currents.

This study furthers the state of knowledge on density current confluences …

Product Qualification And Performance Assessment Of Hsrm Prestressed Concrete Railroad Ties Through Laboratory Testing, Ali Haider Abdulqader

Theses and Dissertations

This study focuses on the performance assessment of prestressed concrete railroad ties made of a newly developed High Strength Reduce Modulus (HSRM) concrete. The HSRM material has been developed by researchers at the University of South Carolina laboratories. The HSRM material was originally considered as a high-performance concrete for highway bridge girders, but it was rejected because it shows very low modulus of elasticity. A current project at USC proposed to use this HSRM material in prestressed concrete railroad ties. The experimental tests during the material development phase of the project showed that the HSRM-HPC has a reduced Modulus of …

Multi-Model Structural Analysis, Wesley Holt

Theses and Dissertations

The uncertainty in modeling earthquake loading is investigated through the comparison of various openSEES models. A series of models is created and the responses compared with each other as well as with a full scale shake table experiment. The openSEES models selected for comparison include two linear models, a nonlinear model using the Steel01 material for the entire cross section, and eight fiber models using reinforcing steel material and various concrete materials.

The models are subjected to a series of nine simulated earthquakes, matching the excitations applied to the shake table test. It is found that all of the models …

Modeling Human-Structure Interaction Using A Controller System, Albert Ricardo Ortiz Lasprilla

Theses and Dissertations

The effects of human loads on structures are difficult to predict because they depend on the type of activity people are performing. However, models for typical activities such as standing, sitting and jumping have been proposed in the literature. Traditional models represent the human body as a system of lumped masses, dampers and springs arranged in a system with multiple degrees of freedom. Arguably, these models might not fully represent the human body because lumped masses, dampers and springs cannot add energy to the overall system. Furthermore, people could react differently to different levels of excitation and other environmental conditions. …

Multiscale Modeling Of Water Transport And The Influence Of Water Quality Parameters On Membrane Processes, Linkel Kwabena Boateng

Theses and Dissertations

Membrane-based desalination processes have become a viable means of producing potable water to meet water resource needs in both industrialized and developing nations. Extensive experimental investigation, in conjunction with computational modeling is critical in the development of sustainable and cost-effective desalination technologies. The overall goal of this dissertation is to develop a multiscale modeling framework to elucidate water and salt transport mechanisms and the influence of water quality parameters on membrane processes. The key tasks involved in this study are: establish a criterion for estimating water flux using Bayesian inference; develop a multiscale framework to connect molecular dynamics (MD) simulations …