Engineering Commons^™

Numerical And Experimental Studies Of Undercut Slopesinclined Along A Bedding Plane, Rithy Ouch

Chulalongkorn University Theses and Dissertations (Chula ETD)

Slope failures along a bedding plane were critical issues and mostly happened in an open pit mining project such as the Mae Moh Mine, Thailand. The prediction of maximum width to which the slope remains stable after an excavation process is required. The aim of this research is to investigate the stability and failure mechanisms of undercut slopes with and without shear pins resting on a bedding plane by means of physical and numerical models. Physical models of slip tests and undercut slopes were made of the humid silica sand No. 6 with 10% of water content and rested on …

Bottom Friction Assessment For Hydrodynamic Currents In The Lower St. Johns River, Henok Kefelegn Demissie

UNF Graduate Theses and Dissertations

A preexisting version of the 2D finite-element hydrodynamic model (code) ADCIRC was modified to enable assimilation of velocity data for calculation of longwave hydrodynamics of the lower St. Johns River. The data assimilation also enables model calibration and parameter estimation of directionally variant Manning’s n value using an anisotropic formulation of bottom roughness. This modified version of the ADCIRC code differs from the original ADCIRC model, as it introduces a module to provide evaluation of directional Manning’s roughness coefficient using observed velocity data for ebb and flood flow durations. The vector-based directional Manning’s n value is found by comparing the …

Effect Of Lateral Stiffness On Bridge Deck Performance, Andrea Del Pilar Toro

UNF Graduate Theses and Dissertations

The use of the empirical deck design method has increased its acceptance due to the economic advantages that it presents when compared to its counterpart, the traditional method. This can be attributed to the fact that the empirical method provides an appropriate design where the deck withstands stress not only due to the steel reinforcement but to an implicit arching membrane stress set-up as an effect of the lateral restraint surrounding the deck slab known as Compressive Membrane Action (CMA).

It has been proved through research that most design codes underestimate the strength of laterally restrained slabs. However, there is …

Comparison Of Hydrologic Model Performance Statistics Using Thiessen Polygon Rain Gauge And Nexrad Precipitation Input Methods At Different Watershed Spatial Scales And Rainfall Return Frequencies, Amanda E. Tancreto

UNF Graduate Theses and Dissertations

As hydrological computer modeling software continues to increase in complexity, the need for further understanding of the value of different model input datasets becomes apparent. Frequently used precipitation model input include rain gauge data and next-generation radar–based (NEXRAD) rainfall data. Rain gauge data are usually interpolated across a model domain using various methods including the Thiessen Polygon methodology, which may be data-sparse in some areas and overly data-dense in others. However, rain gauge data are generally very easy to use in hydrologic model development, often requiring little to no data processing. NEXRAD data have the potential to improve hydrologic runoff …

The Development Of A Hydrodynamics-Based Storm Severity Index, Gabriel Francis Todaro

UNF Graduate Theses and Dissertations

A hydrodynamic-based storm severity scale that ranks the damage potential of a storm at a given coastal area is developed. Seventeen tropical and extratropical storm events at 113 different locations on the Atlantic coast and the Gulf of Mexico are examined in order to create and verify a Storm Severity Index Model (SSIM). The results from the SSIM are then used to create a location-based storm severity scale titled the Twenty-Four Point Storm Severity Scale. The Twenty-Four Point Scale is based on three subsets of factors. The first is the energy flux above the normal mean high water line that …

Damage Detection Methodologies For Structural Health Monitoring Of Thin-Walled Pressure Vessels, Arturo Modesto

Electronic Theses and Dissertations

There is a need in exploring structural health monitoring technologies for the composite structures particularly aged Composite Overwrapped Pressure Vessels (COPVs) for the current and future implementation of COPVs for space missions. In this study, the research was conducted in collaboration with NASA Kennedy Space Center and also NASA Marshall Space and Flight Center engineers. COPVs have been used to store inert gases like helium (for propulsion) and nitrogen (for life support) under varying degrees of pressure onboard the orbiter since the beginning of the Space Shuttle Program. After the Columbia accident, the COPVs were re-examined and different studies (e.g. …

Sustainable Material Solution For Flexible Pavements; Performance Evaluation And Impact Assessment Of Utilizing Multiple Recycled Materials In Hma, Behnam Golestani

Electronic Theses and Dissertations

The demand for pollution-free and recyclable engineering materials has been increased as the cost of energy and environmental concerns have risen. Green material design can lead to better environmental quality and sustainability of civil infrastructure. Road construction is one of the largest consumers of natural resources. Beneficial utilization of recycled materials can result in an important opportunity to save the mining and use of virgin materials, to preserve energy, and to save landfill space. Two main research questions addressed in this study are: (1) How much pollution, energy, natural resources, time and money can be salvaged by applying recycling materials …

Pushover Analysis Of Retrofitted Reinforced Concrete Buildings, Hamidreza Nahavandi

Civil and Environmental Engineering Master's Project Reports

For the past decade or more, the structural engineering profession has been using the nonlinear static procedure (NSP) or pushover analysis. Modeling for such analysis requires the determination of nonlinear properties of each component in the structure, quantified by strength and deformation capacities, which depend on the modeling assumptions. Pushover analysis is carried out for either user-defined nonlinear hinge properties or default-hinge properties, available in some programs based on the FEMA-356 such as SAP2000. While such documents provide the hinge properties for several ranges of detailing, programs may implement averaged values. In the realm of retrofitting of existing structures, few …

Properties Of Microcement Mortar With Nano Particles, Narasimha Reddy Alimeneti

Civil Engineering Theses - Archive

Carbon nanotubes (CNT) and Carbon nanofibers (CNF) are one of the toughest and stiffest materials in the world presently with extreme properties yet to be discovered in terms of elastic modulus and tensile strength. Due to the advanced properties of these materials they are being used in almost all fields of science at nanolevel and are being used in construction industry recently for improvement of material properties. Microcement is fine ground cement which as half the particle size of ordinary Portland cement. In this research the behavior of cement mortar of micro cement with the addition of nanoparticles is studied.Due …

Effect Of Preformed Chloramines And Chlorine To Ammonia Ratio On The Formation Of N-Nitrosodimethylamine (Ndma) In Trwd East Texas Raw Water Delivery System, Khidir Hamad

Civil Engineering Theses - Archive

Tarrant Regional Water District (TRWD) pumps untreated raw water from Richland Chambers and Cedar Creek reservoirs in East Texas to provide water to several customer cities including Arlington and Fort Worth. TRWD adds chloramines to the pipeline to combat biofilm growth, that reduces pipeline capacity and increases pumping costs, and to control zebra mussels, that clog intake structure screens and the pump wet wells. However, addition of chloramines leads to the formation of N-nitrosodimethylamine (NDMA), a potent carcinogen, by reaction of chloramines with nitrogenous organic precursors possibly present in the raw water. NDMA formation presents a challenge to TRWD because …

Fate Of Bulk Hypochlorite Solutions In Two Water Treatment Facilities, Anna Breytus

Civil Engineering Theses - Archive

Measurement of oxyhalides in various strength hypochlorite solutions has been an issue of importance in the last decade, especially in view of the current aim of Homeland Security to reduce the usage of chlorine gas. Hypochlorite solutions have a potential of introducing disinfection by-products when used for water treatment. Previous works have shown the possibility of high levels of chlorate and perchlorate in high strength hypochlorite solutions. Perchlorate is an endocrine disruptor that inhibits iodide intake by the thyroid, thus reducing the production of essential thyroid hormones. Chlorate also has several adverse effects on the blood and thyroid systems. Perchlorate …

Mechanical Behavior Of Grouted Sands, Ryan C. Ortiz

Theses and Dissertations--Civil Engineering

Grouting techniques have been in used for many years, but several new grout materials have surfaced in recent decades that have re-defined the boundaries of the limitations of grouting programs. Typically these applications are used for seepage control in earthen impoundments, but strength of these earthen impoundments should be considered where there is potential for movement in the grouted soil mass. This study investigated initial conditions that could affect grout application effectiveness. The initial conditions in question were soil grain size and in situ moisture content. Two grouts were used, ultrafine and acrylate, and variations in pure grout properties were …

Influence Of Calcium Sulfoaluminate Cement On The Pullout Performance Of Reinforcing Fibers: An Evaluation Of The Micro-Mechanical Behavior, Robert B. Jewell

Theses and Dissertations--Civil Engineering

The objective of this research was to determine the influence of calcium sulfoaluminate (CSA) cement on reinforcing fibers by evaluating the fiber pullout behavior, and bonding characteristics, of a single fiber embedded in a cementitious paste matrix. Four types of fibers commonly used in industry were evaluated: 1) Polyvinyl alcohol; 2) Polypropylene; 3) Coated Steel; and 4) Plain Steel.

Upward trends in energy costs and potential greenhouse gas regulations favor an increased use of construction materials that require lower energy and lower CO₂ emissions to fabricate, such as CSA cement, as opposed to the production of ordinary portland cement …

Deformation-Based Excavation Support System Design Method, Sekyi K. Intsiful

Theses and Dissertations--Civil Engineering

Development in urban areas around the world has steadily increased in recent years. This rapid development has not been matched by the ever decreasing open space commonly associated with urban centers. Vertical construction, thus, lends itself a very useful solution to this problem. Deep excavation is often required for urban construction. Unfortunately, the ground movements associated with deep excavation can result in damage to adjacent buildings. Thus, it is critically important to accurately predict the damage potential of nearby deep excavations and designing adequate support systems.

A new design method is proposed, as an attempt, to address the problem. The …

Prediction Of Strength And Shear Modulus Of Compacted Clays Within An Unsaturated Critical State Framework, Corrie Walton-Macaulay

Theses and Dissertations--Civil Engineering

The objective of this research study is to determine whether the soil stiffness, from which the small-strain shear modulus is determined, can be used to predict the shearing resistance of compacted clay soil, which are invariably under conditions of partial saturation. The research program developed for this objective included three major soil testing programs of matric suction, shear modulus, and strength.

A method to estimate matric suction of field compacted clay soil was presented and it is based on the quantified effect of change in initial void ratio on the soil water characteristic behaviors. With the use of a non-nuclear …

Examining Multiple Approaches For The Transferability Of Safety Performance Functions, Ahmed Tarek Ahmed Farid

Electronic Theses and Dissertations

Safety performance functions (SPFs) are essential in road safety since they are used to predict crash frequencies. They are commonly applied for detecting hot spots in network screening and assessing whether road safety countermeasures are effective. In the Highway Safety Manual (HSM), SPFs are provided for several crash classifications for several types of roadway facilities. The SPFs of the HSM are developed using data from multiple states. In regions where jurisdiction specific SPFs are not available, it is custom to adopt nationwide SPFs for crash predictions then apply a calibration factor. Yet, the research is limited regarding the application of …

Characterization Of Waste-To-Energy (Wte) Bottom And Fly Ashes In Cementitious Materials, Jin Woo An

Electronic Theses and Dissertations

Waste-to-Energy (WTE) ashes (or called as municipal solid waste incineration ashes) have been recycled in the areas of road bed, asphalt paving, and concrete products in many European and Asian countries. In those countries, recycling programs (including required physical properties and environmental criteria) of ash residue management have been developed so as to encourage and enforce the reuse for WTE ashes instead of landfill disposal. However, the U.S. has shown a lack of consistent and effective management plans as well as environmental regulations for the use of WTE ashes. Many previous studies demonstrated the potential beneficial use of WTE ash …

Data-Driven Simulation Modeling Of Construction And Infrastructure Operations Using Process Knowledge Discovery, Reza Akhavian

Electronic Theses and Dissertations

Within the architecture, engineering, and construction (AEC) domain, simulation modeling is mainly used to facilitate decision-making by enabling the assessment of different operational plans and resource arrangements, that are otherwise difficult (if not impossible), expensive, or time consuming to be evaluated in real world settings. The accuracy of such models directly affects their reliability to serve as a basis for important decisions such as project completion time estimation and resource allocation. Compared to other industries, this is particularly important in construction and infrastructure projects due to the high resource costs and the societal impacts of these projects. Discrete event simulation …

Applications Of Computer Vision Technologies Of Automated Crack Detection And Quantification For The Inspection Of Civil Infrastructure Systems, Liuliu Wu

Electronic Theses and Dissertations

Many components of existing civil infrastructure systems, such as road pavement, bridges, and buildings, are suffered from rapid aging, which require enormous nation's resources from federal and state agencies to inspect and maintain them. Crack is one of important material and structural defects, which must be inspected not only for good maintenance of civil infrastructure with a high quality of safety and serviceability, but also for the opportunity to provide early warning against failure. Conventional human visual inspection is still considered as the primary inspection method. However, it is well established that human visual inspection is subjective and often inaccurate. …

Base Flow Recession Analysis For Streamflow And Spring Flow, Debapi Ghosh

Electronic Theses and Dissertations

Base flow recession curve during a dry period is a distinct hydrologic signature of a watershed. The base flow recession analysis for both streamflow and spring flow has been extensively studied in the literature. Studies have shown that the recession behaviors during the early stage and the late stage are different in many watersheds. However, research on the transition from early stage to late stage is limited and the hydrologic control on the transition is not completely understood. In this dissertation, a novel cumulative regression analysis method is developed to identify the transition flow objectively for individual recession events in …

Sustainability Assessment Of A Municipal Utility Complex: A System Of Systems Approach, Tarek Fahmy

Electronic Theses and Dissertations

Construction of municipal utility complexes has to support continuing population growth, economic development, and a widespread of social interest in environmental preservation. Municipalities face challenges in designing, constructing, and operating environmentally sustainable utility complexes, and their primary goal in developing such a complex is to minimize the environmental impact resulting from energy production and waste treatment (both liquid and solid), management, and disposal. However, decision and policy makers lack a system of systems approach that takes into account multiple interdependent systems comprised of the functional system (infrastructure, facilities, operations within the complex…), the economic system, the social/cultural system, and the …

Exploration And Development Of Crash Modification Factors And Functions For Single And Multiple Treatments, Juneyoung Park

Electronic Theses and Dissertations

Traffic safety is a major concern for the public, and it is an important component of the roadway management strategy. In order to improve highway safety, extensive efforts have been made by researchers, transportation engineers, Federal, State, and local government officials. With these consistent efforts, both fatality and injury rates from road traffic crashes in the United States have been steadily declining over the last six years (2006~2011). However, according to the National Highway Traffic Safety Administration (NHTSA, 2013), 33,561 people died in motor vehicle traffic crashes in the United States in 2012, compared to 32,479 in 2011, and it …

Safety At Intersections In Oregon: A Preliminary Update Of Statewide Intersection Crash Rates, Daniel R. Hazel

Civil and Environmental Engineering Master's Project Reports

This research aims to provide a preliminary update to statewide intersection crash rates for the state of Oregon using 2008-2013 crash data and a statewide sample of 129 intersections where two (or more) state-owned facilities intersect. Using intersections where state-owned facilities represent both the major and minor legs of the intersection allows for the maintenance of up-to-date intersection crash rates by eliminating time-intensive traffic volume data collection. Due to the frequency and severity of crashes at intersections, development of easily obtained intersection crash rates is important to assess trends and effectiveness of safety countermeasures employed at these locations in the …

The Effect Of Water Temperature On In-Stream Sediment Concentration And Transport Rate, Jennie Tyrrell

Dissertations, Master's Theses and Master's Reports

Global climate change may result in rising temperatures. As a result, ecological health and the human use of rivers may be impacted. The hydrologic cycle, watershed hydrology, and in-stream hydraulics are dynamic systems, influenced by human activities, natural events, and climate. Although known drivers like precipitation and stream velocity govern sediment processes, the effect of water temperature on sediment transport remains unclear. In-stream sediment movement could lead to blocked harbors, flooding, and degradation of vulnerable fish habitat. To better understand how fluctuations in water temperature affect sediment dynamics, six transport models were analyzed on the Niobrara River, with water temperatures …

Quantitative Non-Destructive Evaluation Of Rebar Diameter And Corrosion Damage In Concrete Using Ground Penetrating Radar, Md Istiaque Hasan

Civil Engineering Dissertations - Archive

The purpose of this study is to develop new methods for quantitative estimation of rebar diameter and loss of area of rebar due to corrosion using Ground Penetrating Radar (GPR). The existing methods of determining the rebar diameter using GPR are not accurate and the existing methods for evaluating corrosion using GPR are qualitative. The study included in this dissertation uses a 2.6 GHz antenna to estimate the diameter of rebar using two different approaches. The approaches use digital image processing of GPR ragargrams and maximum normalized reflection amplitude form the rebar to estimate the diameter. A novel method to …

Discrete Element Modeling Of Geogrid Reinforced Granular Media, Asheesh Pradhan

Civil Engineering Dissertations - Archive

Geogrids have proven to be economical solution in improving ground conditions for construction in foundations, retaining walls, railway tracks, and pavements. Hence researchers have started studying the geogrid reinforcement in detail to understand the working of geogrid and parameters affecting it. Following the advent of faster computers and efficient algorithms researcher have started using discrete element method (DEM) to study geogrid reinforcement since DEM provides particulate level of interaction and understanding and is the closest resemblance of the physical phenomenon. However, the research works are widely spread lacking comprehensive review of factors that can affect such models. This research studies …

Counting And Classification Of Highway Vehicles By Regression Analysis, Mingpei Liang, Xinyu Huang, Chung-Hao Chen, Alade Tokuta

Electrical & Computer Engineering Faculty Publications

In this paper, we describe a novel algorithm that counts and classifies highway vehicles based on regression analysis. This algorithm requires no explicit segmentation or tracking of individual vehicles, which is usually an important part of many existing algorithms. Therefore, this algorithm is particularly useful when there are severe occlusions or vehicle resolution is low, in which extracted features are highly unreliable. There are mainly two contributions in our proposed algorithm. First, a warping method is developed to detect the foreground segments that contain unclassified vehicles. The common used modeling and tracking (e.g., Kalman filtering) of individual vehicles are not …

The Simulation & Evaluation Of Surge Hazard Using A Response Surface Method In The New York Bight, Michael H. Bredesen

UNF Graduate Theses and Dissertations

Atmospheric features, such as tropical cyclones, act as a driving mechanism for many of the major hazards affecting coastal areas around the world. Accurate and efficient quantification of tropical cyclone surge hazard is essential to the development of resilient coastal communities, particularly given continued sea level trend concerns. Recent major tropical cyclones that have impacted the northeastern portion of the United States have resulted in devastating flooding in New York City, the most densely populated city in the US. As a part of national effort to re-evaluate coastal inundation hazards, the Federal Emergency Management Agency used the Joint Probability Method …

Numerical Modeling And Analysis Of Tidal Variance And Marsh Productivity In The Guana Tolomato Matanzas National Estuarine Research Reserve, Florida, Amanda S. Tritinger

UNF Graduate Theses and Dissertations

Long term sustainability in salt marsh and mangroves is dependent on dominant species, such as Spartina alterniflora, to capture organic and inorganic sediment. The research analyzes that sustainability. This work demonstrates the prediction of hydrodynamics and biomass density of salt marsh to provide useful information for the planning and mitigation of sea-level rise impacts on marsh sustainability in the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR), Florida. An advanced circulation code was applied to simulate hydrodynamics (i.e., shallow water equations) in the GTMNERR. The model used a set of parameters and conditions based on the GTMNERR domain to predict …

Adaptivity For Meshfree Point Collocation Methods In Linear Elastic Solid Mechanics, Joshua Wayne Derrick

Theses and Dissertations

This study presents the behavior of local node adaptivity for point collocation meshfree numerical methods and its application to linear elastic solid mechanics. A bisection approach to meshfree adaptivity will be presented with numerical examples showing that convergence is achieved. A threshold value is required from the user and this value is an acceptable change in gradient for the problem. If the change in gradient between 2 nodes exceed this limit, a node is added at the mid-point between the two nodes. This process applies to all nodes in the model. Once the refinement is complete, the model is processed …