Digital Commons Network^™

Modular Composite Sandwich Structures For Thermal And Structural Retrofitting Of Existing Buildings, Marc Al Ghazal

Masters Theses

Around 40% of global energy consumption and 30% of worldwide carbon dioxide (CO2) emissions are attributed to buildings. Most of this consumption is dedicated to ensuring thermal comfort. The goal of this research was to develop and field validate retrofit solutions to improve the energy efficiency of buildings. Exterior cladding panels were designed and tested to ensure adequate thermal and structural performance. Sandwich panels (glass fibers reinforced polymer (GFRP) skins and polymeric foam cores) were fabricated using the vacuum assisted resin transfer molding (VARTM) process. Extruded polystyrene (XPS) and polyurethane (PU) foams were compared as core materials through a series …

The Current State Of Practice Of Building Information Modeling, Kevin P. Brooks

Masters Theses

Building Information Modeling (BIM) has become extremely prominent in the construction industry in the past twenty years. It serves as a digital repository that can, when used to its fullest potential, combine all aspects of designing, building, and managing a structure in one place, alongside all the data produced in those processes. The construction industry has to date struggled to increase productivity alongside similar fields, such as the manufacturing industry, though the construction industry generally has far more stakeholders on one project than the manufacturing industry. Further, building designs are becoming more complex while project schedules are becoming tighter. As …

The Effects Of Hurricane Wind Field Characteristics On Wind Blade Loads, Michael S. Tsai

Masters Theses

Over recent years, offshore wind energy has been growing around the world. This necessitates placing wind turbines directly in or near the oceans where hurricanes can be. Previous research has suggested that hurricane wind veer and direction change can have adverse loading effects on the turbine. Such effects can create damage to the blade or worsen existing ones. Currently, there is no known design standard for addressing wind veer and direction change specifically from hurricanes. Quantifying the loading contribution from these phenomena is not abundant either.

This thesis seeks to demonstrate a proposed procedure for defining design veer profiles and …

Post-Fire Damage Inspection Of Concrete Tunnel Structures, James Viglas

Masters Theses

In general, tunnels are designed with an abundance of safety regarding structural integrity, however, there can be uncertainty related to structural performance after a fire event. The residual condition of a tunnel after a fire is dependent on fire intensity and duration. The goal of this study is to correlate visual and material characteristics of structural and non-structural components of tunnels with fire temperature and exposure time. This can be further related to the residual capacity of structural members in a tunnel, providing insight into safety and overall functionality. Experimental results show that the visual response of materials with heat …

Investigating Disparities And Safety Equity In Pedestrian Nighttime Crashes In Michigan, Sia Isaria Mwende

Masters Theses

For the past eleven years (2011 - 2021) in Michigan, 76 percent of all fatal pedestrian crashes occurred at night. Over the same period, about 36 percent of pedestrian nighttime crashes were fatal or incapacitating (KA), while only 25 percent of daytime pedestrian crashes were fatal or incapacitating (KA). Previous studies suggest that, overall, poor neighborhoods and racial minorities are associated with more pedestrian crashes. With more fatal and incapacitating pedestrian crashes occurring at night, it is imperative to examine how these crashes are distributed by economic status and racial makeup. Therefore, this study aims to investigate the racial and …

Correlation Between Laboratory Testing Results And In-Situ Sidewalk Scaling, Brian R. Shea

Masters Theses

Scaling tests aim to induce scaling behavior in concrete specimens similar to environmental conditions. The efficacy of laboratory tests’ ability to match environmental conditions is important to be able to evaluate the durability of concrete exposed to freeze-thaw cycles and de-icers. This study attempts to correlate results between two existing scaling test standards, ASTM C672 and the BNQ NQ 2621-900. The correlation is done via scaling evaluation including computer-based photogrammetric analysis, visual ratings, and cumulative mass loss measurements. Then a correlation between the laboratory testing and in-situ sidewalk panel specimens is made via visual ratings.

Comparison Of Scaling Performance Between Sidewalks Placed Using Hot And Cold Weather Concreting Procedures, Likhitha Rudraraju

Masters Theses

This study investigates the performance of concrete sidewalks placed using hot and cold weather concreting practices. The effect that curing methods, types of deicers, and supplementary cementitious material content have on the scaling resistance of concrete is examined in the laboratory and the field. After one winter, petrographic analysis was conducted on the cores from the sidewalk panels.

The results from field evaluation indicate that the concrete sidewalks placed using hot weather concreting showed better resistance against scaling than those placed using cold weather concreting. The results also suggest that the effect of curing method depends on the concreting procedure …

Wind-Wave Misalignment Effects On Multiline Anchor Systems For Floating Offshore Wind Turbines, Doron T. Rose

Masters Theses

Multiline anchors are a novel way to reduce the cost of arrays of floating offshore wind turbines (FOWTs), but their behavior is not yet fully understood. Through metocean characterization and dynamic simulations, this thesis investigates the effects of wind-wave misalignment on multiline anchor systems. Four coastal U.S. sites are characterized in order to develop IEC design load cases (DLCs) and analyze real-world misaligned conditions. Stonewall Bank, Oregon showed the highest 500-year extreme wave height, at 16.6 m, while Virginia Beach, Virginia showed the highest 500-year wind speed, at 56.8 m/s. Misalignment probability distributions, at all sites, are found to converge …

Selecting Consolidation Procedures For Making Concrete Specimens, Paige Marie Toebben

Masters Theses

"The goal of this research was to reevaluate ASTM C31 Standard Practice for Making and Curing Concrete Test Specimens in the Field, as well as deepen our understanding of the relationship between the consolidation process, concrete composition, and workability. An improved understanding of this area will help to reduce variability in concrete quality. The project involved evaluating the effect of different consolidation methods on concrete specimens with changing levels of workability. To do this, concrete cylinders were created with varying viscosities by adjusting the water-to-cement ratio (w/c) and water-reducing agent. More cylinders were created with varying paste volumes while keeping …

A Network Of Low-Cost Multi-Pollutant Air Quality Sensors For Evaluating Fine-Scale Exposure Disparity In Twin Cities, Mn, P M Varuni Abhayaratne

Masters Theses

"Poor air quality is detrimental to health and is a leading environmental risk factor for early death globally. The massive scale of urbanization and population growth has led urban air quality to become a global concern as the release of air pollutants into the atmosphere continues to increase. Air quality has traditionally been monitored using reference-grade monitoring stations that are expensive and sparsely distributed. Low-cost sensors can complement existing regulatory networks to provide more spatial detail, capturing fine-scale variations. This study investigates spatiotemporal pollutant patterns, exposure disparities and environmental justice using data collected from a two-year (2019-2021) deployment of a …

Rapid-Throughput Analysis Of 1,4-Dioxane In Plants By Centrifugal Sampling And Phytoforensic Analysis For Site Delineation And Assessing Enhanced Rhizodegradation, Anthony Eberechukwu Oha

Masters Theses

"Owing to its broad use and environmental persistence, 1,4-dioxane (dioxane) poses a notable threat to public health and is recalcitrant to traditional remedial systems. Dioxane moves readily in an aqueous environment and is an emerging contaminant in drinking water, surface water, groundwater, and wastewater. The extent of dioxane in the biosphere is also difficult to delineate, particularly in the subsurface. Phytoremediation has demonstrated the potential for dioxane groundwater remediation. Recent findings indicate that plant-microbial symbiosis may be more advantageous for limiting potential transport and transfer into plant tissues and the atmosphere. Bioaugmentation of the rhizosphere paired with soil amendments has …

Designing Exterior Lighting For Safety And Comfort While Minimizing Light Pollution, Energy Consumption, And Cost, Stephen Michael Simmons

Masters Theses

"Artificial light at night brings many benefits to society. However, these benefits do not come without costs. One environmental issue that is often overlooked in the design of public spaces and infrastructure is light pollution. At the expense of large amounts of energy, light pollution causes numerous harmful effects on human health, ecosystems, and the night sky. Today, the problem is becoming more widespread, especially with the increasing use of bright, white LED luminaires. Thus, it is imperative for designers and engineers to create smarter lighting designs that not only allow for safety and comfort at night but also promote …

Performance Evaluation Of Sediment Basin Designs For Highway Construction Sites In Tennessee, Jeffery Cole Emmett Jr

Masters Theses

Performance of three sediment basin designs were tested; they were: 1) the TDEC standard design with a forebay, 2) the TDOT design with an inlet check dam, and 3) the TDOT standard design that does not include an inlet check dam. An 1/17 of an acre scaled physical model sediment basin, was constructed next to an elevated outdoor open flume used to mix known water volumes and sediment mass routed by gravity-flow into the basin. The measurement for performance was simply the percent sediment mass retained in the basin from the total input per experimental run (percent sediment removal). Three …

Joint Failure Probability Of Dams Based On Probabilistic Flood Hazard Analysis, Matthew G. Montgomery

Masters Theses

Probabilistic risk methods are becoming increasingly accepted as a means of carrying out risk-informed decision making regarding the design and operation of structures such as dams. Probabilistic risk calculations require the quantification of epistemic and aleatory uncertainties not investigated through deterministic methodologies. In this hydrological study, a stochastic sampling methodology is employed to investigate the joint failure probability of three dams in adjacent, similarly sized watersheds within the same Hydrologic Unit Code (HUC) 6 basin. A Probabilistic Flood Hazard Analysis (PFHA) framework is used to simulate the hydrologic loading of a wide range of extreme precipitation events across the combined …

Structural Steel Connection Design For Tensile Rupture By Advanced Inelastic Analysis, Kaylalyn H. Truman-Jarrell

Masters Theses

Connections are critical in structural steel buildings for transferring forces from member to member. Connections must be designed for safety and to ensure they serve their intended function. Many resources are available to engineers designing connections with common configurations and loads. But connection designers often encounter configurations and loading conditions for which there is little guidance. In these cases, design by advanced inelastic analysis can be advantageous. IDEA StatiCa is a steel connection design software for design by advanced inelastic analysis. In this software, some limit states are captured in the same manner as standard strength equations, while others are …

Numerical And Experimental Investigation Of Machinery Isolation Featuring Gap-Type Nonlinear Rotational Inertial Mechanisms For Marine Applications, Alexandra C. Shafer

Masters Theses

Transmitted noise and vibration from equipment and machinery is an ongoing and serious priority onboard marine vessels as noise and vibrations interfere with system operations and can compromise the functionality of the vessel. Vibration isolation systems have been widely studied for civil and mechanical applications because of the damage that can occur from extreme vibrations and excessive motion. Conventional vibration isolation systems often include components such as springs and dampers in the isolation layer, but researchers have begun to incorporate other devices including, linear rotational inertial mechanisms (RIMs), often known as inerters, to enhance traditional vibration isolation systems. The inerter …

Measuring Accessibility To Food Services To Improve Public Health, Efthymia Kostopoulou

Masters Theses

Food accessibility has lately been of primary interest given its impact on public health outcomes. This thesis illustrates the gaps in food access by applying spatial analysis in Massachusetts accounting for a variety of demographic and socioeconomic factors. The number of grocery stores, farmers markets, and convenience stores within 1/4 and 1 mile of the Census tracts’ centroids are the two accessibility metrics used in the spatial analysis. In addition, a regression model is developed using the Gradient Boosting machine learning method to show the relationship between the socioeconomic factors and the number of grocery stores within 1 mile of …

Euplectella Aspergillum’S Natural Lattice Structure For Structural Design & Stability Landscape Of Thin Cylindrical Shells With Dimple Imperfections, Zoe Y. Sloane

Masters Theses

The first portion of this thesis assesses the structural application of a bracing design inspired by the deep-sea sponge, Euplectella Aspergillum. Many studies have investigated the natural strength found in the unique skeletal structure of this species. The braced design inspired by the sponge features square frames with two sets of cross-braces that are offset from the corners of each frame, creating a pattern of open and closed cells. This study reports the results of multiple Finite Element Analysis (FEA) computations that compare the described bracing pattern to a more common bracing design used in structural design. The designs …

Assessing Phenotypic Response Of Plants Irrigated With Municipal Solid Waste Landfill Leachate Using Computer Visualization, Rahel Pommerenke

Masters Theses

"Most solid waste collected in the US is disposed of in sanitary landfills, which have a lingering legacy of unintended negative impacts on the environment. Landfill design and operation are expensive, prone to multiple failure modes, and often do not address human and ecological risks presented by contaminants of emerging concern. A notable and common failure mechanism is leachate production. Moisture in the waste mixes with infiltrating water to form wastewater that must be collected and treated prior to discharge. Recycling leachate at landfills by recirculating it onto vegetated landfill covers relies on the evapotranspiration potential of plants to reduce …

Effect Of In-Situ Formed Nano-Calcite Particles On Hydration And Properties Of Cement-Based Materials, Bowen Tan

Masters Theses

The in-situ preparation of nano-calcite via bubbling method and the effects of the nano-calcite on the hydration process and properties of the cement-based materials are investigated in this research. The nano-calcite is synthesized under different conditions and added into Portland cement to prepare test samples. The bubbling method is then introduced in upcycling the municipal solid waste incineration (MSWI) ashes, and the effects of the upcycled MSWI ashes on the hydration of Portland cement is investigated. Experimental results illustrate that the COâ‚‚ bubbling method can produce nanometer-to-sub- micron-sized calcite particles, and the synthesis rate and the morphology of the nano-calcite …

Dissolved Organic Carbon And The Potential Role To Stream Acidity In The Great Smoky Mountains National Park, Jason R. Brown

Masters Theses

A substantial societal shift towards environmental awareness has focused research efforts on the impacts of pollution on natural landscapes. Improvements to pollutant regulations and technology have resulted in sizeable reductions of atmospheric deposition of anthropogenic acids, especially nitrates and sulfates, which has altered the role of these ions in the environment. As such, understandings of environmental chemistry dynamics have required regular updating.

Through the National Park Service Vital Signs monitoring program, increases in precipitation pH observed in Great Smoky Mountains National Park (GRSM) has been attributed to the reduction of inorganic acid concentrations. Unfortunately, these improvements have not been uniformly …

Design And Experimental Evaluation Of A Small-Scale Buckling Restrained Brace Analog, Lindsay K. Helferich

Masters Theses

In the event of an earthquake, structures experience large lateral loads that can lead to weak story mechanisms and result in premature building collapse. Strongback braced frames (SBF) are a type of seismic force resisting system that aim to evenly distribute horizontal loads up the height of the building to mitigate this failure mechanism. Previous research shows that SBFs are a promising way to better design for seismic demands, but these systems have not been fully explored to best exploit the design space. This work is a part of a project that aims to provide both numeric and experimental verification …

Terrestrial Laser Scanning Technology For Measuring Streambank Retreat Along East Fork Poplar Creek And Calculating The Effect On Mercury Release., José L. Martínez Collado

Masters Theses

Mercury (Hg) is a globally distributed inorganic pollutants of human concern. The high toxicity is mainly related to the capacity of Hg species to accumulate and biomagnify along aquatic food webs. Along East Fork Poplar Creek (EFPC), erosion represents the principal mercury input into the local waters, eventually reaching humans through the food chain. This research project aimed to monitor streambank erosion along a mercury-contaminated creek using Light Detention and Ranging (Lidar) technology and erosion pins. A Terrestrial Laser Scanner (TLS) was used to generate high-resolution point clouds from August 2020 to January 2021 across nine streambank locations to detect …

Effect Of Radiation On Bond Behavior Between Concrete And Steel Bar: Development Of Experimental Protocol, Mohammed Abdelrahman

Masters Theses

There is a need to assess the effect of radiation on the behavior of bond strength between steel reinforcement and concrete. However, there is geometrical constraints in the cylindrical capsule which limit the size of concrete samples. Thus, developing a protocol to produce pullout sample and a test setup is needed.

A protocol for fabricating high-precision concrete samples with embedded \#2 steel bar has been developed based on the results of an experimental program. A pullout system has also been developed to investigate the bond activity of concrete and steel. This research looks at two different aggregate sizes 3/8 inch …

Tall Timber In Denver: An Exploration Of New Forms In Large Scale Timber Architecture, Andrew P. Weuling

Masters Theses

Wood has been utilized by humans for thousands of years in the construction of our built environment. More recently, our expanded understanding of the material and the advancement of engineered wood have allowed us to use wood like never before. Concrete and steel, however, have emerged as the main materials used in large scale construction in the late 19^th and 20^th Centuries. As we are battling and searching for solutions to climate change, the importance of wood in large scale construction has increased as not only is its carbon intensity is lower than steel and concrete, but its …

Parametric Study Of Integral Abutment Bridge Using Finite Element Model, Asako Takeuchi

Masters Theses

A parametric study of single-span integral abutment bridge (IAB) was conducted using finite element analysis to explore the effects of various load conditions, bridge geometries, and soil properties. This study investigated the difference between the live load distribution of traditional jointed bridges and integral abutment bridges (IABs) under HL-93 truck component load. The results showed that AASHTO live load distribution factors (LLDFs) were overly conservative by up to 50% to use for IABs. LLDFs for IABs proposed by Dicleli and Erhan (2008) matched well for interior girder moment, but they were unconservative for exterior girder moment by up to 20% …

Post-Fire Assessment Of Concrete Tunnel Structures, Nicholas C. Menz

Masters Theses

Although concrete tunnel structures can lose strength and long-term durability due to fire, the literature on the remaining capacity of structures after fire events is very scattered, and no published post-fire inspection protocols specifically for concrete tunnel structures are available. This work aims to summarize and synthesize the current state of knowledge of the deleterious effects of fire on the residual condition of concrete tunnel structures and how the extent and degree of fire damage can be assessed. The scope of this work includes an extensive literature review, heat testing of some common tunnel elements, and residual strength testing of …

Quantifying Tree Canopy Contributions To Stormwater Runoff Reductions In Urban Watersheds Of The Southeastern United States, Matthew C. Howard

Masters Theses

Urban stormwater is a major contributor to surface water degradation in the United States, prompting cities to invest in ways to naturally capture, store, and slowly release runoff through “Green Infrastructure” (GI). One often overlooked potential contributors to stormwater management are urban trees, an integral part of a given city’s GI. Interception is of particular interest and describes a tree’s ability to capture and store rainfall, reducing the volume of stormwater that can degrade urban streams during storm events. While rainfall interception for full canopy, forested environments is well studied, limited research is available that characterizes the interception of open-grown …

Bioretention Cell Performance Under Shifting Precipitation Patterns Across The Contiguous United States, Matthew Weathers

Masters Theses

As climate change produces shifts in precipitation patterns, communities will need to understand how the performance of green stormwater infrastructure (GSI) may be impacted. Bioretention cells are one of the most commonly implemented forms of GSI for their ability to reduce peak discharge and filter pollutants and are a vulnerable component of stormwater infrastructure. Projections in future climate indicate that bioretention cells may be at risk of losing their existing function due to deviations in precipitation frequency and intensity. General circulation models (GCMs) downscaled to regional climate models (RCMs) can provide climate change projections at a high spatial resolution but …

Using Survey Data To Understand Ridesourcing In Tennessee: Who, Where, When, And Why?, Cassidy Kilmer Crossland

Masters Theses

With companies like Uber and Lyft leading the way, ridesourcing has grown and continues to grow in popularity in the United States since its introduction just over ten years ago. While research on this new transportation mode has largely focused on national level trends and studies of large metropolitan areas, little has been written about its impacts in smaller and mid-sized cities and states. This paper aims to understand the socioeconomic characteristics and travel behavior trends of those using ridesourcing in less studied regions, using Tennessee as a case study. This thesis has three parts: a literature review of past …