Civil Engineering Commons^™

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 …

An Experimental Comparison Between Fine Aggregate And Quarry Fines Based On Mortar Block Strength, Karthik Boregowda

Theses and Dissertations

The strength properties of mortar mainly depend on the materials used for casting. Each material has its own importance for cement mortar strength. In this research, quarry fines, a waste by-product, replaced a portion of fine aggregate in mortar. This research focuses on compressive strength of cement mortar using American Society for Testing and Materials standards. The specimens were cast in standard 2”x 2” inch molds. The compressive strength of blocks with replacement of fine aggregate by quarry fines at 15%, 25%, 30%, and 50% was tested at 7, 14 and 28 days of curing. The results were compared with …

Vulnerability Model Of Residential Structures Subject To Hurricane Induced Wind, Surge And Inundation, Mohammad Baradaranshoraka

Theses and Dissertations

Annualized hurricane-related losses to the built environment in the United States are in the billions of dollars. According to the National Oceanic and Atmospheric Administration, in 2010 39% of the United States population, or 123.3 million inhabitants, lived in a coastal county. This population is expected to increase by 8% from 2010 to 2020. The majority of these people live in buildings prone to hurricanes. The hurricanes can result in wind damage (due to high wind and/or wind-driven rain infiltration) and water damage (due to storm surge and waves or freshwater flooding) to the building and its contents, which are …

Estimation Of Groundwater Loads Into A Coastal Estuary Using Seawat, Antonio S. Berber Jr.

Theses and Dissertations

The research of regional groundwater flow is of vital importance at the Indian River Lagoon (IRL) due to the potential contribution groundwater flow has on nutrients into the IRL. If too many nutrients are introduced into the IRL, algal blooms could occur and impact the health of IRL system. The IRL is a coastal estuary located on the east coast of Florida. Submarine groundwater seepages (SGD) and groundwater loads into the IRL were numerically estimated by using SEAWAT, a program designed to simulate variable-density groundwater flow coupled with multi-species solute transport. Models were completed at three different study transects that …

Application Of Ground Penetrating Radar To Highway-Related Problems, Rauf Rejab Hussein

Theses and Dissertations

The Broadway Bridge, constructed in 1923, crosses the Arkansas River in the downtown area of Little Rock, AR and was the main crossing point between Little Rock and North Little Rock. The structural deterioration of the bridge reached a level beyond patch and repair. Accordingly, the Arkansas Highway and Transportation Department (AHTD), in collaboration with the City of Little Rock, allocated the required resources ($98.4M) to demolish and replace the bridge. Due to the age of the bridge site and the limited knowledge of the subsurface utility layout, it became clear that geotechnical work be done in order to map …

Correlating Strength And Stiffness Data Of The Pencel Pressuremeter And Triaxial Compression Tests In Florida Sands, Jacob William Jansen

Theses and Dissertations

The poorly graded sands found throughout Florida provide geotechnical engineers with a difficult challenge when performing testing samples in laboratory tests. These challenges have caused lab tests such as the triaxial compression test to be overlooked. Since geotechnical engineers estimate strength and stiffness parameters from basic field tests, they often produce overly conservative designs. Understanding how the automated in-situ PENCEL Pressuremeter (PPMT) test correlates with the triaxial compression test can reduce the time and costs associated with laboratory triaxial testing. Results from triaxial tests yield a Young’s Elastic Modulus, shear strength, and internal friction angle. Results from a PPMT test …

Recommended Selective Maintenance And Rehabilitation Treatment Approach For Air Force Primary Rigid Runway Pavement Systems, Christopher M. Twigg

Theses and Dissertations

The Air Force is facing the challenge to preserve the current inventory of 154 million square yards of paved airfield assets while at the same time reducing the budget by $36.2 billion between fiscal years 2015-2019. This research sought to determine a selective maintenance and rehabilitation treatment approach that allocates resources efficiently to preserve the degrading pavement assets in the financially constrained environment. Air Force pavement inspection reports from the past five years provided 4289 observed pavement distress data points for this research. The data was inputted into the pavement management software, PAVER, to calculate the Pavement Condition Index (PCI) …

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 …

Maintenance And Improvement Of The Florida Public Hurricane Loss Model, Nicholas Wayne Miller

Theses and Dissertations

The Florida Public Hurricane Loss Model (FPHLM) predicts insurance losses due to hurricane events. This thesis describes maintenance tasks of the vulnerability component of the FPHLM. First, it explores the applicability of recent experimental research to the FPHLM opening protection, water intrusion, and roof pressure modeling features of the Personal Residential (PR) and Commercial Residential Low-Rise (CR-LR.) models. These changes were not implemented because either more experimental data is needed or they had no impact on the losses. Next, it discusses an additional update to the CR-LR model that changed the soffit area calculations, sampling bounds within the rain model, …

Building Exposure Study In The State Of Florida And Application To The Florida Public Hurricane Loss Model, Joshua Michalski

Theses and Dissertations

Modeling hurricane events with models such as the Florida Public Hurricane Loss Model (FPHLM) is essential for insurance and reinsurance companies to estimate projected losses. Additionally, the models can be used by public officials to estimate and mitigate damages while also developing public safety policies to reduce the amount of damage and loss of life during a catastrophic event. The FPHLM combines hurricane event simulation and building vulnerability models to predict insurance portfolios losses. Before vulnerability functions are applied to insurance portfolios to determine total losses, these functions are weighted based upon building characteristics statistics representative of a given building …

Simulation Of Value Stream Mapping And Discrete Optimization Of Energy Consumption In Modular Construction, Md Mukul Chowdhury

Theses and Dissertations

With the increased practice of modularization and prefabrication, the construction industry gained the benefits of quality management, improved completion time, reduced site disruption and vehicular traffic, and improved overall safety and security. Whereas industrialized construction methods, such as modular and manufactured buildings, have evolved over decades, core techniques used in prefabrication plants vary only slightly from those employed in traditional site-built construction. With a focus on energy and cost efficient modular construction, this research presents the development of a simulation, measurement and optimization system for energy consumption in the manufacturing process of modular construction. The system is based on Lean …

Evaluating Soil Properties And Cyclic Loading Effects Of Florida’S Clayey Silty Fine Sand Soils Associated With High Pile Rebound, Ali Fadil M. Omar

Theses and Dissertations

Throughout the state of Florida, pile rebound has been encountered while driving large displacement piles. During periods of excessive rebound, the piles could not achieve further penetration and could require an excessive number of blows to advance the pile into the ground. This phenomenon affecting pile driving is called high pile rebound producing construction delays, higher costs; and may lead to pile damage. A comprehensive experimental program was performed involving the characterization and identifications of the typical soils properties associated with high pile rebound during pile installation. The research focuses on the determination of the relationships between high and no-rebound …

Alkali Silica Reaction In Concrete Made From Arkansas Region, Adithya Reddy Mallu

Theses and Dissertations

Alkali-Silica Reaction is an unwanted reaction which occurs over time between cement paste and silica. This in turn alters the expansion of the aggregate and often in an unpredictable way, which will result in loss of strength of concrete and complete failure. This research studies the effects of using locally available coarse and fine aggregates available in Arkansas. This research will provide the necessary information in selecting the type of aggregate that is to be used in constructions and a viable comparison between different aggregates available in Arkansas have been made. Different materials used for preparation of concrete samples have …

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 …

Evaluation Of Unbound Pavement Layers Moduli Using The Miniaturized Pressuremeter Test, Alaa Mohammed Shaban

Theses and Dissertations

A small version of pressuremeter known as Miniaturized Pressuremeter (MPMT) was designed and built to provide high quality pavement parameters. The device, which is a modified version of PENCEL Pressuremeter (PPMT) has a 6 inch inflatable probe capable of quickly and reliably measuring the stress-strain response of thin pavement layers. The MPMT stress-strain data can be used as inputs to evaluate existing pavement structures as a part of a pavement management system, and as critical inputs in empirical pavement design methods. To check in-situ operational performance of the new probe, twenty four MPMT and PPMT tests were performed in parallel …

Civil Engineer Company Grade Officer Training Needs Analysis For Contingency Operations, Brian S. Greszler

Theses and Dissertations

In terms of active duty personnel, the USAF is the smallest it has ever been since its creation in 1947. With fewer personnel to accomplish essential tasks, the training of Airmen is more important than ever. Outdated and irrelevant training can lead to gaps in the knowledge of trainees. The purpose of this research was to analyze the training needs of Civil Engineer (CE) Company Grade Officers (CGOs) in the contingency environment. This was done by first conducting a Job Analysis (JA). The JA resulted in a list of 36 critical tasks and 58 important Knowledge, Skills, and Abilities (KSAs). …

Alkali Silica Reaction (Asr) Mitigation For Arkansas Region, Lois Farouk Kamel

Theses and Dissertations

The objective of this research is to mitigate and prevent the alkali silica reactivity (ASR) in highway construction projects. ASR is a deleterious reaction initiated when the silica content of the aggregate reacts with alkali hydroxides in the mix in the presence of relatively high moisture content. The ASR results in the formation of an expansive white colored gel-like material which forms the destructive tensile stresses inside hardened concrete. Different types of local aggregates available in the State of Arkansas were mixed, mortar bars and concrete specimens were poured according to the ASTM specifications. Specimens' expansion was measured versus time, …

Development Of Lightweight Concrete Mixes For Construction Industry At The State Of Arkansas, Mohammed Abdulwahab Almansouri

Theses and Dissertations

As the construction industry evolved, the need for more durable, long lasting infrastructure increased. Therefore, more efforts have been put to find new methods to improve the properties of the concrete to prolong the service life of the structural elements. One of these methods is the use of lightweight aggregate as an internal curing agent to help reducing self-desiccation and shrinkage. This research studied the effects of using locally available lightweight aggregate (expanded clay), as a partial replacement of normal weight aggregate in the concrete matrix. The concrete mixtures contained lightweight aggregate with a replacement percentage of 12.5, 25, 37.5, …