Organizational Unit:

School of Civil and Environmental Engineering

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https://hdl.handle.net/1853/70760

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College of Engineering

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Organizational Unit

Georgia Water Resources Institute

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Georgia Transportation Institute

Organizational Unit

Environmental Microbial Genomics Laboratory

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https://finding-aids.library.gatech.edu/agents/corporate_entities/385

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Publication Search Results

Now showing 1 - 10 of 860

Residual Deterrence In Action: Exploring The Impact Of License Plate Readers In Warner Robins' Smart City Digital Twin Model

(Georgia Institute of Technology, 2023-12-13) Sonar, Nidhi Sandip

With an emphasis on crime prevention, this thesis investigates the residual effect of License Plate Readers (LPRs) within a Smart City Digital Twin (SCDT) model. It highlights the integration of Artificial Intelligence (AI) and LPRs for improved surveillance while tracing the historical background of crime. The study presents the Warner Robins SCDT model, which shows encouraging outcomes in the use of dynamic LPR deployment to curb criminal acts. The residual effect of LPRs, which shows continued deterrence even after relocation, is analyzed using statistical tests on the crime records of Warner Robins (WR) and the location of cameras during the intervention period of eighteen weeks. The results demonstrate the presence of a residual effect for the period under consideration, and the possibility of yielding unique results or insights through advanced testing and research based on different parameters.
Accessibility To Healthcare Via Public Transit: A Case Study Of The Atlanta Metropolitan Area

(Georgia Institute of Technology, 2023-12-12) Baral, Ivee

Access to transportation is one of the major social determinants of health (SDOH). Environmental conditions where people are born, live, learn, work, play, worship, and age have an impact on a variety of health, functioning, and quality-of-life outcomes and risks; these conditions are known as social determinants of health (American Hospital Association, 2023). For households without cars, public transportation is essential for accessing healthcare (Liu et al., 2022). Adequate public transportation can help ensure patients are able to attend their healthcare appointments as scheduled and decrease the number of missed appointments. On the other hand, a lack of public transit could disrupt health outcomes by leading to delayed diagnoses or exacerbating existing conditions (American Hospital Association, 2023). Due to varying socioeconomic factors such as race, ethnicity, and car ridership, different households have unequal access to healthcare, so transit is their only way of reaching healthcare facilities (Liu et al., 2022). This study will investigate the accessibility of healthcare in the Atlanta Metropolitan Area via MARTA bus routes to understand how accessible healthcare is for transit-dependent individuals. Transit dependency constitutes individuals who have limited access to other modes of transportation, such as those above 65, below 18, and people with disabilities (American Public Transit Association, 2017). The goal of this study is to identify the census tracts in the study area that have limited access to healthcare facilities via transit, especially for transit-dependent people. The study will focus on the MARTA bus routes rather than the MARTA rail, as there is greater reach through the bus network.
Analysis Of Infrastructure Investments And Jobs Act, Federal Compliances, Issues And Determining A Framework Of Resources For Compliance Management

(Georgia Institute of Technology, 2023-12-05) Aggarwal, Ayush

The Infrastructure Investments and Jobs Act (IIJA) is a historic legislation bipartisan bill that has empowered the infrastructure development agencies with grants to undertake capital projects to meet the infrastructural needs of the USA. The study presents an analysis of the funding with around a fifth of the funding dedicated to the roads, bridges, and other major projects segment. The study sheds light on the tenets and objective of the government spending and also presents programs and grants available. It further elaborates on how these grants are classified as formula and discretionary and explains the fundamental differences in these granting methods. The study analyzes public data to determine the breakdown of the funding for the available formula grants. Chapter 3 of the study elaborates on the grant lifecycle to elaborate and educate the reader on the grant lifecycle from pre-award to post-award compliance requirements. The literature review and professional seminars indicated the lack of development of internal controls regarding federal compliance requirements by local public agencies and non-conventional grant recipients have hampered the agencies from accessing such funding opportunities. Therefore, this study highlights the major compliance areas required for federal participation in highway transportation construction projects. The study highlights the matrices published by the government for funding opportunities, and subsequently highlights the challenges with the compliance requirements. 5 challenges were recognized and subsequently 14 general compliance areas were identified for non-conventional entities to develop their internal controls and procedures. 11 federal compliance areas were identified where such compliance requirements might arise in the federally aided projects. These 11 areas are elaborated for the compliance requirements and subsequently chapter 8 provides tools and existing resources for development of such compliance requirements for the departments. Chapter 9 of the study recognizes 11 existing frameworks of resources that can be leveraged by the agencies for management of the federal compliance requirements. The summary of the existing frameworks like the USDOT Technical assistance programs and Local Technical Assistance programs will guide the readers toward the correct and relevant information regarding the compliance areas. Finally, this research while elaborating and highlighting federal compliance requirement management for the local public agencies highlights the need for a dynamic compliance navigator tool that integrates the available public resources by various organizations to streamline the federal compliances and enhance safety, quality and integrity of the project. The streamlined compliance navigator will aid the government in this massive undertaking of infrastructural development and deliver the projects On Time and on Budget.
Structural Testing Of Non-Proprietary UHPC For Closure Pours Used In Standard GDOT Precast Bridge Deck Panels

(Georgia Institute of Technology, 2023-08-28) Ngeme, Lixrine Epie

Ultra-high-performance concrete (UHPC) is a type of concrete that is known for its exceptional strength, durability, and resistance to cracking. Proprietary UHPC is primarily made by combining cement, silica fume, quartz flour, fine sand, high-range water reducers, and steel or polymer fibers. UHPC has been used in a variety of applications, including bridges, tunnels, high rise buildings, and other structures that require high strength and durability. One of the main advantages of UHPC is its ability to support high loads with relatively thin sections, which can lead to significant cost savings in construction. In 2018, researchers at the Georgia Institute of Technology developed a non-proprietary ultra-high-performance concrete (UHPC) mix that could be produced using locally available materials. The mix consisted of Portland cement, metakaolin, fine sand, water, and a high-range water reducer. The mix design demonstrates the required 28-day compressive strength of at least 18,000 psi. This UHPC mix was designed to meet the high-performance requirements of bridge construction while also being cost-effective and environmentally sustainable. The closure joint is a critical component of a bridge that accommodates the expansion and contraction of the bridge deck due to temperature changes. The UHPC mix was used to fill the closure joint between two adjacent bridge slabs. The performance of the UHPC mix in the closure joint was evaluated through a series of tests, including compression tests, and flexural tests. The UHPC mix was found to have high compressive and flexural strength, as well as excellent adhesion to the bridge decks. The primary goal for this research was to use the non-proprietary UHPC mix developed in the previous research at Georgia Institute of technology, to perform a large structural test on closure joint of bridge slabs in Georgia. Two tests were performed successfully and detailed reports from observing these tests followed. Insights were gained from these tests as to the viability of the non-proprietary mix for closure pour applications. The mix proved successful in this regard, indicated by both-large scale structural test specimens failing via crushing of the precast concrete panels rather than failure being governed by the UHPC joint. The results of the tests demonstrated that the non-proprietary UHPC mix developed in Georgia was a viable option for use in bridge construction. The UHPC mix showed superior performance compared to traditional concrete mixes and could provide a cost-effective and environmentally sustainable solution for bridge construction.
Experimental study on the nonlinear mixing of ultrasonic waves in concrete using array technique

(Georgia Institute of Technology, 2023-08-21) Weiss, Fiona Jacqueline

This research develops a procedure that combines array technology with non-collinear ultrasonic wave mixing to detect and scan internal microscale damage in a concrete prism specimen. By mixing two wave fronts of incident shear waves generated by two ultrasonic transducer arrays, one can exploit the underlying mechanics of nonlinear wave mixing to create a longitudinal mixed wave and measure the magnitude of this nonlinear wave at a frequency that is the sum of the fundamental frequencies. The frequency of the incident waves is chosen such that it is low enough to propagate without being scattered by the in- herently inhomogeneous concrete microstructure, while the resulting nonlinear phenomena are still sensitive to damage much smaller than the wavelength of the incident waves. The arrays enable beam steering, making it possible to scan for damage along an arc. Overall, scanning and imaging at different locations in a large volume throughout the specimen’s thickness is accomplished by manually adjusting the placement of the two arrays to move the mixing zone any desired, internal depth, while beam steering is used to scan at different locations of the same depth close to each other. The effectiveness of the proposed technique is demonstrated by characterizing different types of damage embedded at known locations in a concrete prism specimen. The results of this thesis are in accordance with previous research and show that beam steering along an arc to scan for damage in the concrete specimen is in fact possible.
Design, Construction and Testing of Pedestrian Bridges Built with Decommissioned 53-meter Wind Turbine Blades

(Georgia Institute of Technology, 2023-08-01) Zhang, Zoe

Due to the rise in popularity of wind energy in recent decades, projections show that millions of tons of glass-fiber reinforced polymer (GFRP) composite wind turbine blades will be decommissioned within the next 20-30 years, most of which will be landfilled or incinerated. The Re-Wind Network is a multinational research team focusing on this growing issue of blade waste, particularly on finding applications for decommissioned blades in infrastructure. This thesis focuses on the design, construction, and testing plan of an 18.5 meter pedestrian bridge made using decommissioned 53-meter blades. Two of these bridges, denoted as BladeBridges by the Re-Wind Network, will be installed in a public park in the City of Atlanta. This thesis presents the design and analysis of three bridge configurations that were considered for the BladeBridge, all of which use the wind blades as the primary longitudinal girders. The first option uses two blades with supports on either side of the span. The second option is a double-blade cantilever option, with both supports on one side of the span. The final option is a single-blade bridge, supporting the deck off to one side and placing the blade-girder into flexure and torsion. Structural analysis for each option is presented using effective moduli and section properties provided by the wind blade original equipment manufacturer (OEM), as well as load combinations specified by the AASHTO pedestrian bridge design code. Maximum stresses and deflections, as well as the constructability given the constrained site plan, were used to assess the feasibility of each option. The first option was chosen as the most feasible for the given bridge site, and further design details of the selected option are presented including overall elevations, foundation design, and steel connection design. Finally, a load testing and instrumentation setup plan is provided for a BladeBridge prototype that will be installed at the Georgia Tech Structural Engineering and Materials Laboratory.
Characterizing Pedestrian Activity in Georgia via Clustering of Passively Collected Traffic Signal Data

(Georgia Institute of Technology, 2023-07-31) Shorey, Julie

Establishing practices for quantifying and monitoring patterns of activity for all modes is essential when it comes to multimodal transportation planning and engineering. As walking is a fundamental form of travel, as well as one of the most vulnerable forms, it is imperative that these practices extend to pedestrian travelers. Transportation agencies currently have invested in standardizing systems for characterizing vehicular activity, however, data and practices are less readily available when it comes to non-motorized users. Existing systems also may not be transferable due to the differences between motorized and non-motorized travel behavior (FHWA, 2022). This study focuses on identifying pedestrian activity patterns through a generally widespread and underutilized data source, traffic signal data, and aims to categorize pedestrian activity trends in the Georgia context through shape-based statistical clustering methods. Ultimately, the results of this analysis will help to inform site selection initiatives of a larger pedestrian volume estimation project.
Design of High-Strength Polygonal Cold-Formed Steel Built-Up Sections Using the Direct Strength Method

(Georgia Institute of Technology, 2023-07-31) Sakpunpanom, Korawat

Cold-formed steel (CFS) structural members, which are increasingly important in building construction, offer numerous shapes and are created through roll-forming machines or bending processes. Advancements in metallurgy, particularly the development of high -strength low-alloy (HSLA) sheet with a minimum yield strength of 100 ksi (690 Mpa), have further expanded the use of cold-formed sections in lightweight and advanced structural applications, such as in the solar energy industry. Despite their benefits, cold-formed sections are susceptible to cross-sectional instabilities like local and distortional buckling, which reduce their ultimate capacity. To enhance their strength, connecting individual sections using fasteners to create built-up sections is advantageous. The research employs the Direct Strength Method (DSM) as a practical flexural strength prediction approach for polygonal shape built-up sections, compared to the advanced Finite Element Analysis (FEA). The predictions from both methods are also validated against the experimental program. Furthermore, the Digital Image Correlation (DIC) system is utilized to capture the buckling of the specimens during testing precisely.
Riverine Hydrokinetic Energy Resource Assessment of the United States

(Georgia Institute of Technology, 2023-07-31) Slater, Emma Catherine

This study focuses on characterizing the riverine hydrokinetic energy resource and its natural variability for the United States. The results are an estimate of the theoretical re- source available for 360 hydrokinetic turbine deployments. The theoretical resource is quantified for each of the 18 hydrologic units in the conterminous United States based on a number of spatial and hydrologic considerations. Discharge data obtained from the Na- tional Water Model Version 2.1 retrospective dataset is processed and used to create flow duration curves for selected segments. The segments are selected based on 3 criteria: (1) highest average flowrate, (2) spatial distribution of 0.5 degrees, and (3) absence of a dam. The geographic and temporal variability are analyzed by identifying annual and interan- nual trends in the flow. The identified trends are compared to global rainfall and societal patterns in water usage to serve as the basis for a discussion regarding the potential future conditions impacting hydrokinetic project development. The theoretical power generated by installing hydrokinetic energy devices is computed along the segments spanning each hydrologic unit, giving an overall estimate for the potential theoretical resource available. The overall theoretical hydrokinetic resource for the United States is estimated to be 29.4 TWh/yr for 360 turbine project sites. This is slightly smaller than the estimated re- source from the same locations in the University of Alaska Anchorage (2012) report by the Electric Power Research Institute. The increased resolution and accuracy of the discharge, slope, and slope length values used in this thesis versus those used in the University of Alaska Anchorage (2012) report is likely the source of the difference. The seasonal and inter-annual variation trends identified varied by basin. Across the basins, generally the annual energy peaked in spring and summer months, while annual energy was lowest in late fall and winter months. This trend was prevalent for the Lower Mississippi, Pacific Northwest, and Missouri basins. The South Atlantic and California basins’ annual energy peaked in later winter with lower values in the fall. Annual energy appears to have slightly increased on average from 1980 to 2020 considering annual vari- ation, with a peak in 2019. This trend was especially prevalent for the Lower Mississippi and Missouri basins. While the Lower and Upper Mississippi regions were found to have both the highest resource and magnitude of variability from the mean value per basin, the Texas and Souris-Red-Rainy regions were found to have the largest relative changes annu- ally from 1980-2020. The Pacific Northwest and Upper Colorado regions experienced the highest seasonal variation within an average year relative to the other basins, likely due to the influence of snowmelt.
Investigation of Tidal Energy Resource Assessment Estimates and Assumptions for a Channel Connecting a Bay to the ocean using Numerical Modeling

(Georgia Institute of Technology, 2023-07-31) Varner, Jacob Robert

There is a rising global demand for renewable energy as the world shifts away from fossil fuels. A promising source of renewable energy is the ocean tides. Tides can generate strong and predictable currents through narrow channels of coastal estuaries with potentially significant power potential. An essential step in pursuing tidal energy, as with other forms of energy, is determining the amount of energy available through an energy resource assessment. These assessments commonly start with a regional feasibility study to identify individual sites with potential. The accepted method for doing so can be cumbersome because of the extensive numerical modeling. However, methods for estimating tidal energy have been developed for regional feasibility studies using analytical models with simplifications and assumptions. In this thesis, a method for estimating the maximum average power within a channel linking a bay to the open ocean was evaluated using numerical modeling. Several study cases were designed using two different bay geometries and a range of tidal amplitudes to test the effectiveness of the method across a variety of plausible conditions. Ultimately, the results from the numerical simulations and the estimations across the study cases were compared for validation. The simplified analytical solution was shown to be fairly robust, agreeing well with the results from the numerical simulations.