Engineering Commons^™

The Feasibility Of High Strength Stainless Steel In Prestressing Applications For Pile Design, Cara Morton

USF Tampa Graduate Theses and Dissertations

Approximately 50% of the Nation’s infrastructure was built over 40 years ago for a 50 year service life according to the National Association of Corrosion Engineers [72]. To mitigate the cost of major repair or replacement at 50 years, AASHTO now requires all new bridge construction to have a 100 year service life. One of the main challenges in achieving this goal is avoiding corrosion, especially in warm, saltwater environments like those found in the Southeastern United States. Elements that cross the waterline (piles) are a weak link the infrastructure. Good quality concrete easily maintains a service life of 75+ …

Pursuing Resilience Of Coastal Communities Through Sustainable And Integrated Urban Water Management, Pacia Díaz

USF Tampa Graduate Theses and Dissertations

Reliability of water supply in the urban setting has become essential for communities to function and thrive. It is needed for more than mere human consumption and well-being. Although modern cities have water treatment and distribution systems, pressures from urbanization, population growth and the anticipated pressures of climate change are affecting the quality of water supply and the reliability of treatment and distribution systems. There is therefore an urgent need to take appropriate measures to improve the resilience of water supply systems before the impacts are irreversible.

Improving the resilience of water supply systems can be a challenge. In the …

Numerical Modeling Of Concrete Flow In Drilled Shaft, Jesudoss Asirvatham Jeyaraj

USF Tampa Graduate Theses and Dissertations

Drilled shafts are cylindrical, cast-in-place concrete deep foundation elements. Their construction involves drilled excavation of soil or rock using large diameter augers, and placement of the necessary reinforcing steel in the excavation followed by concreting. Where a high water table is encountered, drilling slurry is used to support the excavation walls and concreting is tremie-placed. Even though the history of drilled shaft construction goes back to the 1950s, the occurrence of anomalies persists in the form of soil inclusions, reduction in shaft cross-sectional area and exposure of reinforcement. One of the main reasons for the anomalies is attributed to the …

Improving Early-Age Cracking Resilience And Durability Of Concrete Elements, Ananya Markandeya

USF Tampa Graduate Theses and Dissertations

Control of early-age cracking in concrete structures due to restrained deformation, thermal and/or autogenous, presents a major durability challenge for state highway agencies. This study details research conducted on improving the early-age cracking resilience of plain concrete and supplementary cementitious materials (SCM) blended concrete. Three specific areas, within concrete structural elements, with high incidence of early-age cracking are addressed:

• High early-age strength (HES) concrete mixtures used in slab-replacement of Jointed Plain Concrete Pavements (JPCP)
• Use of metakaolin (MK) in bridge deck mixtures
• Use of slag blended concrete, at high cement replacement levels, in massive structural elements

Three cracking mitigation measures …

Enhancement Of Rainfall-Triggered Shallow Landslide Hazard Assessment At Regional And Site Scales Using Remote Sensing And Slope Stability Analysis Coupled With Infiltration Modeling, Thilanki Maneesha Dahigamuwa Rajaguru Mudiyanselage

USF Tampa Graduate Theses and Dissertations

Landslides cause significant damage to property and human lives throughout the world. Rainfall is the most common triggering factor for the occurrence of landslides. This dissertation presents two novel methodologies for assessment of rainfall-triggered shallow landslide hazard. The first method focuses on using remotely sensed soil moisture and soil surface properties in developing a framework for real-time regional scale landslide hazard assessment while the second method is a deterministic approach to landslide hazard assessment of the specific sites identified during first assessment. In the latter approach, landslide inducing transient seepage in soil during rainfall and its effect on slope stability …

Wastewater In Context: Systems-Based Approaches To Improving Wastewater Infrastructure Transitions, Christine Prouty

USF Tampa Graduate Theses and Dissertations

Coastal communities and ecosystems around the world are some of those most vulnerable to the impacts of climate change. In particular, the wastewater treatment systems in these areas are on the forefront of the effects of increasing frequency, duration, and intensity associated with extreme weather events. As such, decision making about adopting new wastewater technologies or transitioning to an improved treatment portfolio is an important area of research for coastal communities because they are critically linked to the health of the nearby aquatic ecosystems (i.e. tourism, fishing, cultural heritage, climate protection).

The decision making process about technology adoption and transitions …

A Theoretical And Practical Analysis Of The Effect Of Drilling Fluid On Rebar Bond Strength, Kelly Costello

USF Tampa Graduate Theses and Dissertations

Drilled shafts are large cylindrical cast-in-place concrete structural elements that can be favored due to cost-effectiveness. These elements however, require strict quality control during construction to ensure a stable excavation. Drilling fluid is often used in construction to attain this stability. Drilling fluid, or slurry, can be ground water or salt water, but is typically made from a mixture of water and mineral or polymer powder to form a viscous fluid slightly more dense than ground water. During concreting, the drilling fluid is displaced by the heavier concrete, which is tremie placed at the base of the excavation from the …

The Icarus Floating Membrane Photobioreactor For Microalgae Cultivation In Wastewater: Advancing Technology From Lab To Field Prototype, Melanie Pickett

USF Tampa Graduate Theses and Dissertations

The ICARUS membrane photobioreactor, conceptualized and preliminarily tested at the University of South Florida, provides a viable platform for algae cultivation using wastewater as a growth medium. Progression of the technology is tracked using NASA’s Technology Readiness Level scale, and is herein described. Through the work described in this manuscript, the technology has evolved from TRL 3 to TRL 5. Completing the suggested future work will readily move the technology to TRL 6 and beyond.

The first study investigated the co-location of algal cultivation with wastewater treatment. This coupling provides a steady source of water and nutrients for algal growth. …

An Analytical Solution For Attainment Of Field Capacity, Ali Aldrees

USF Tampa Graduate Theses and Dissertations

Field Capacity (FC) is a key parameter to quantify in agricultural engineering, irrigation controlling, and soil physics studies. For instance, irrigation studies focuses on determining the optimal amount of water needed by plants to grow following an irrigation system and therefore relies on determining FC. Likewise, the value of FC is a good indicator of soil textures, structures and pore size distributions. For example, loamy soils have a wider distribution of pores leading to high FC values. FC depends on multiple physically-grounded variables which include matric potential value (ψ_FC ), water content at FC (θ_FC ), specific drainage time to …

Comparison Of Bacterial And Viral Reduction Across Different Wastewater Treatment Processes, Aayushi R. Vagadia

USF Tampa Graduate Theses and Dissertations

Today billions of people live without access to basic sanitation facilities, and thousands die every week due to diseases caused by fecal contamination associated with improper sanitation. It has thus become crucial for decision makers to have access to relevant and sufficient data to implement appropriate solutions to these problems. The Global Water Pathogen Project http://www.waterpathogens.org/ is dedicated to providing an up-to-date source of data on pathogen reduction associated with different sanitation technologies that are important if the world is to achieve the Sustainable Development Goals (SDGs) related to health and sanitation provision. In this research, a subset of the …

Application Of A Floating Membrane Algal Photobioreactor For Freshwater Aquaculture, Hsiang-Yang Shyu

USF Tampa Graduate Theses and Dissertations

As the global population grows, water and food demand also increase. The intensive aquaculture industry has helped to mitigate these problems. In order to make aquaculture sustainable, it is necessary to remove the abundant nutrients produced by fish in the water. In this study, the role of the microalga of Chlorella vulgaris in the Isolated Cultivation of Algal Resources Utilizing Selectivity (ICARUS) membrane photobioreactor was evaluated for nutrient control in the aquaculture system. The production of algal biomass, the removal rate of nutrients, and the impact of microalgae on cultured organisms were monitored during the operation of aquaculture systems. At …

Numerical Analysis Of Leakage Through Defective Geomembrane Liners In Embankment Dams, Sarper Demirdogen

USF Tampa Graduate Theses and Dissertations

Placing a geomembrane liner in the core of a dam is an alternative construction technique to traditional clay core types. This study aims to assess the performance of such internal geomembrane sealing systems in an earthen dam. Two-dimensional (2D) numerical analysis was performed to evaluate leakage through defective seams within an earthen dam. Five possible applications of internal geomembrane systems were initially modeled to locate the zero-pressure lines in an earthen dam. Then, another application where the geomembrane is placed on the upstream face was modeled to compare the upstream and internal geomembrane systems. The results of this study show …

The Role Of Forests In Securing Hydropower Needs Of Cambodia, Mohit Kaura

USF Tampa Graduate Theses and Dissertations

Hydropower relies on protection of watersheds to regulate water and sediment yields. Deforestation accelerates the rate of soil erosion, thereby increasing the amount of river sediments heading to the dam's reservoir, decreasing the longevity of the dam. In Cambodia in particular, recent deforestation rates are among the largest on the planet, and forests are expected to disappear within the lifespan of proposed dams. The cost of protecting and restoring forested watersheds can be considered as an annual investment towards sustainable reservoir management and hydropower generation. A modeling framework is developed to estimate the sediment accumulation in reservoirs from deforestation-driven soil …

Mathematical And Numerical Modeling Of Hybrid Adsorption And Biological Treatment Systems For Enhanced Nitrogen Removal, Karl A. Payne

USF Tampa Graduate Theses and Dissertations

High nutrient loading into groundwater and surface water systems has deleterious impacts on the environment, such as eutrophication, decimation of fish populations, and oxygen depletion. Conventional onsite wastewater treatment systems (OWTS) and various waste streams with high ammonium (NH4+) concentrations present a challenge, due the inconsistent performance of environmental biotechnologies aimed at managing nutrients from these sources.

Biological nitrogen removal (BNR) is commonly used in batch or packed-bed reactor configurations for nitrogen removal from various waste streams. In recognition of the need for resource recovery, algal photobioreactors are another type of environmental biotechnology with the potential for simultaneously treating wastewater …

Connected Autonomous Vehicles: Capacity Analysis, Trajectory Optimization, And Speed Harmonization, Amir Ghiasi

USF Tampa Graduate Theses and Dissertations

Emerging connected and autonomous vehicle technologies (CAV) provide an opportunity to improve highway capacity and reduce adverse impacts of stop-and-go traffic. To realize the potential benefits of CAV technologies, this study provides insightful methodological and managerial tools in microscopic and macroscopic traffic scales. In the macroscopic scale, this dissertation proposes an analytical method to formulate highway capacity for a mixed traffic environment where a portion of vehicles are CAVs and the remaining are human-driven vehicles (HVs). The proposed analytical mixed traffic highway capacity model is based on a Markov chain representation of spatial distribution of heterogeneous and stochastic headways. This …

Impact Of Recirculating Nitrified Effluent On The Performance Of Passive Onsite Hybrid Adsorption And Biological Treatment Systems, Amulya Miriyala

USF Tampa Graduate Theses and Dissertations

Approximately 25% of households in the U.S. treat their wastewater onsite using conventional onsite wastewater treatment systems (OWTS). These systems typically include a septic tank or a series of septic tanks followed by a soil absorption system. They effectively remove biochemical oxygen demand (BOD), total suspended solids (TSS), fats and grease but are not designed to remove significant amounts of nitrogen. High nitrogen loading to coastal and ground waters can be dangerous to aquatic life and public health. Hence, there is a need for advanced onsite wastewater treatment systems that can effectively remove nitrogen. Making enhanced nitrogen removal for OWTS …

Expediting The Consolidation Of Clayey Soils Utilizing Microwaves, Thilini Jayatissa

USF Tampa Graduate Theses and Dissertations

Post-construction settlement has been an issue in the field of construction due to the excessive time taken for the dissipation of pore water pressure. This is significant for construction carried out on clayey soils primarily due to the low permeability of clayey soils. Therefore, attention has been directed at finding means of increasing the rate of pre-consolidation. Recent research has focused on the effects of temperature on consolidation. It has been shown that elevated temperature increases the hydraulic conductivity of pore water due to both the reduction of viscosity and differential volumetric expansion of soil and water. This results in …

Hydraulic Performance And Vulnerability On Sanitary Sewer Overflow In Southern Pinellas County, Fl, Uchechi O. Akabogu

USF Tampa Graduate Theses and Dissertations

Rain-induced sanitary sewer overflow due to high infiltration is a significant challenge for many utilities, including Pinellas County utilities. The main aim of this study is to develop a hydraulic model to analyze the performance of the existing sanitary sewer system, especially during intense rainfall events.

To calculate the flow inputs for the model, a times series analysis was performed to separate the inflow and infiltration from the actual sewer flow. Using the Stevens-Schutzbach method, daily Base Infiltration (BI) was calculated and was subtracted from the total observed flow to give the Dry Weather Flow (DWF). Adjusting the DWF by …

Efficient Adjacency Queries And Dynamic Refinement For Meshfree Methods With Applications To Explicit Fracture Modeling, James Olliff

USF Tampa Graduate Theses and Dissertations

Meshfree methods provide a more practical approach to solving problems involving large deformation and modeling fracture compared to the Finite Element Method (FEM). However meshfree methods are more computationally intensive compared to FEM, which can limit their practicality in engineering. Meshfree methods also lack a clear boundary definition, restricting available visualization techniques. Determining particle locations and attributes such that a consistent approximation is ensured can be challenging in meshfree methods, especially when employing h-refinement. The primary objective of this work is to address the limitations associated with computational efficiency, meshfree domain discretization, and h-refinement, including both placement of particles as …

Underground Stormwater Treatment Performance In Urban Coastal Catchments: Case Study Of Baffle Boxes In The City Of Tampa, Awet Eyob Tsegay

USF Tampa Graduate Theses and Dissertations

In coastal urban regions, underground stormwater treatment units are suitable infrastructure options because they take less space where premium land is expensive. Even then, they should be accessible and ideally small enough to fit into existing stormwater networks. Since 2003, the City of Tampa and Florida’s Department of Transportation (FDOT) have installed 47 baffle boxes into the city’s stormwater pipe networks. Baffle boxes are underground stormwater treatment structures designed to capture sediments and floating debris. Since their deployment, many challenges regarding their practical sediment capturing performance was raised by the city.

The objective of this research was to evaluate the …

Caregiver Perception And The Role Of Seasonality In Under-Five Childhood Diarrhea Incidence In Svay Rieng Province, Cambodia, Brian S. Wells

USF Tampa Graduate Theses and Dissertations

Diarrheal disease has long been known to be a burden to children worldwide. Although child mortality rates as a result of diarrhea have decreased over the past two decades, overall diarrhea incidence has remained relatively stable. In Cambodia, diarrhea was the third most prevalent outpatient diagnosis for children under five in 2012, with a reported incidence rate of 12 per 100 children, up from 7 per 100 children in 2008 (Ministry of Planning Cambodia, 2012). Cambodia is an agricultural country with 80% of the population living in rural areas (National Institute of Statistics Ministry of Planning, 2013). Many are also …

Regulatory Methodology And Unmitigated Wetland Loss In Southwest Florida, Kathleen B. Castor

USF Tampa Graduate Theses and Dissertations

This research used Geographical Information System (GIS) data to estimate the acreage of wetland loss due to small-scale activities (taking into account exempt, permitted, and unauthorized activities) in the Southwest District of the Department of Environmental Protection (DEP) between 2006 and 2011 and compared that net loss with the unmitigated wetland net loss that DEP documented during that time for authorized activities and violations that were discovered. The comparison allowed an estimation of the extent of undocumented small-scale unmitigated wetland loss that occurred during those six years. DEP records show that 88% of non-compliance cases remain unresolved, and the net …

Dynamic Modeling Of An Advanced Wastewater Treatment Plant, Komal Rathore

USF Tampa Graduate Theses and Dissertations

Advanced wastewater treatment plants have complex biological kinetics, time variant influent rates and long processing times. The modeling and operation control of wastewater treatment plant gets complicated due to these characteristics. However, a robust operational system for a wastewater treatment plant is necessary to increase the efficiency of the plant, reduce energy cost and achieve environmental discharge limits. These discharge limits are set by the National Pollutant Discharge Elimination System (NPDES) for municipal and industrial wastewater treatment plants to limit the amount of nutrients being discharged into the aquatic systems.

This document summarizes the research to develop a supervisory operational …

Framework Integrating Climate Model, Hydrology, And Water Footprint To Measure The Impact Of Climate Change On Water Scarcity In Lesotho, Africa, John W. Pryor

USF Tampa Graduate Theses and Dissertations

Water scarcity is a problem that will be exacerbated by climate change. Being able to model the effect of climate change on water scarcity is important to effectively plan the use of future water resources. This research integrated the Soil and Water Assessment Tool (SWAT), climate model, and water footprint analysis to measure the impact of climate change on future water scarcity. This was achieved through two objectives. The first objective was to create a modeling framework that links the output from climate model to SWAT and combined streamflow outputs from SWAT with water footprint analysis to measure how climate …

An Evaluation Of Pit Latrines And User Perception Of Excrement In Ngäbe Communities In Panama, James A. Libby

USF Tampa Graduate Theses and Dissertations

At the end of the Millennium Development Goal (MDG) period in 2015, 2.3 billion people, 31% of the global population, still did not have access to even basic sanitation services. Of these people, 892 million still practice open defecation, and 856 million people use unimproved facilities such as pit latrines without a slab or platform or hanging latrines or bucket latrines (JMP 2017). Sustainable Development Goal (SDG) Target 6.2 now aims to achieve adequate and equitable sanitation and hygiene for all and sets the ambitious target of eradicating open defecation by 2030. While the number of people open defecating was …

Investigations On Frp-Concrete Bond, Mostfa Al Azzawi

USF Tampa Graduate Theses and Dissertations

This dissertation presents findings from three separate investigations, a laboratory study and two field studies that evaluated the durability of the Fiber Reinforced Polymer (FRP)-concrete bond. The laboratory study explored the role of porosity on CFRP-concrete bond following immersion in warm water. Two disparate field studies measured residual bond after 20 years outdoor exposure of FRP repairs of full-size masonry walls and after 12 years for partially submerged piles supporting the Friendship Trail Bridge, Tampa Bay.

The ACI 440 code requires the same surface preparation for all externally bonded FRP concrete repairs. This disregards the role of porosity that is …

Selection Of Energy Systems In Aquaculture Through A Decision Support Tool Considering Economic And Environmental Sustainability, Youngwoon Kim

USF Tampa Graduate Theses and Dissertations

Aquaculture had already been distinguished as an important component of global food security and economics. However, aquaculture has expanded at the cost of natural resources and the environment. The vulnerability of the aquaculture industry due to the consequences of global environmental changes and energy price fluctuations has been addressed in various studies. The identification, planning, and implementation of sustainable energy systems are important to ensure the long term economic and environmental sustainability of aquaculture.

This research investigated sustainable energy systems for aquaculture using a life cycle approach, allowing for the identification of the most sustainable energy options under different geographical …

Assessment Of Drinking Water Quality Management And A Treatment Feasibility Study For Brick By Brick Water Storage Tanks In Rakai Uganda, James V. Murduca

USF Tampa Graduate Theses and Dissertations

Reliable access to safe drinking water is one necessity for humans to live without concern for major health risks. The overall goal of this research is to improve the public health, through improved drinking water, for communities in the Rakai District in Uganda, directly, and other communities in the world, indirectly, via dissemination of knowledge. This study specifically assessed the knowledge of drinking water quality in regards to public health, their sanitation measures, and water treatment methods for users of Brick by Brick rainwater harvesting tanks in the Rakai District (N = 28) by using a knowledge, attitudes, and practice …

Field Testing Of Affordable Well Head Protection For Locally Manufactured, Self-Supply Pitcher Pumps On Manually Driven Tubewells In Madagascar, Michal Usowicz

USF Tampa Graduate Theses and Dissertations

Lack of water access is an issue of global importance. The WHO and UNICEF’s Joint Monitoring Program estimated that in 2015 71% of the world’s population used a safely managed drinking water source and 89% of the world’s population used an improved water source within a 30-minute round trip of home. Madagascar’s national statistics lags far behind these global statistics with 54% of the population using improved water sources, 31% using unimproved water sources, and 16% with no service at all.

This research studied water access in Madagascar with self-supply Pitcher Pumps attached on hand-driven tubewells. The term self-supply in …

Impact Of Substrate To Inoculum Ratio On Methane Production In High Solids Anaerobic Digestion (Hs-Ad) Of Food Waste, Yard Waste, And Biosolids, Phillip James Dixon

USF Tampa Graduate Theses and Dissertations

High solids anaerobic digestion (HS-AD) is an alternative for managing the organic fraction of municipal solids waste (MSW), which produces mainly methane (CH4) and fertilizer as byproducts. HS-AD offers a potentially more economically and environmentally sustainable option compared with landfilling or incineration waste-to-energy facilities. However, HS-AD is a complex process requiring specific microbial communities working together symbiotically. Previous studies have found that the substrate to inoculum (S/I) ratio affects CH4 production and yield in HS-AD reactors by affecting substrate mass and energy transfer as well as microbial activity. In this thesis, biochemical methane potential (BMP) assays were used to investigate …