Civil Engineering Commons^™

Design Of Small Scale Anaerobic Digesters For Application In Rural Developing Countries, Laurel Erika Rowse

USF Tampa Graduate Theses and Dissertations

The high incidence of upper respiratory diseases, contamination of waterways due to pathogens and nutrients from human and animal wastes, unsustainable deforestation, gender disparities in burden of disease due to unequal exposure to indoor air pollutants, and carbon black emissions from the burning of solid fuels are interrelated problems in many developing countries. Small scale anaerobic digestion provides a means of alleviating these problems by treating livestock waste onsite to produce biogas (methane and carbon dioxide) in rural areas in developing countries. Fuel can then be used for cooking, lighting, and heating. Methane fuel is an alternative to traditional three-stone …

A Discrete-Continuous Modeling Framework For Long-Distance, Leisure Travel Demand Analysis, Caleb Van Nostrand

USF Tampa Graduate Theses and Dissertations

This study contributes to the literature on national long-distance travel demand modeling by providing an analysis of households' annual destination choices and time allocation patterns for long-distance leisure travel purposes. An annual vacation destination choice and time allocation model is formulated to simultaneously predict the different destinations that a household visits and the time it spends on each of these visited destinations, in a year. The model takes the form of a Multiple Discrete-Continuous Extreme Value (MDCEV) structure (Bhat, 2005; Bhat, 2008). The model assumes that households allocate their annual vacation time to visit one or more destinations in a …

The Evaluation Of Hybrid Slurry Resulting From The Introduction Of Additives To Mineral Slurries, Kyle Douglas Yeasting

USF Tampa Graduate Theses and Dissertations

Drilled shaft construction often requires the use of drill slurry to maintain borehole stability during excavation and concreting. While drill slurry may be composed of fluids ranging from air to petroleum, drilled shaft construction typically makes use of water based drilling fluids. Although clean water may be utilized as a drilling fluid, a premixed slurry consisting of water, minerals, and/or polymers is more commonly used. Florida Department of Transportation (FDOT) specifications require the use of mineral slurry for all primary structures. The slurry resists the intrusion of groundwater, slows the outward migration of drilling fluid from the excavation, and aids …

Minimal And Symmetric Global Partition Polynomials For Reproducing Kernel Elements, Mario Jesus Juha

USF Tampa Graduate Theses and Dissertations

The Reproducing Kernel Element Method is a numerical technique that combines finite element and meshless methods to construct shape functions of arbitrary order and continuity, yet retains the Kronecker-δ property. Central to constructing these shape functions is the construction of global partition polynomials on an element. This dissertation shows that asymmetric interpolations may arise due to such things as changes in the local to global node numbering and that may adversely affect the interpolation capability of the method. This issue arises due to the use in previous formulations of incomplete polynomials that are subsequently non-affine invariant. This dissertation lays out …

Oxygen Diffusion Characterization Of Frp Composites Used In Concrete Repair And Rehabilitation, Chandra K. Khoe

USF Tampa Graduate Theses and Dissertations

Many independent studies have conclusively demonstrated that fiber reinforced polymers (FRP) slow down chloride-induced corrosion of steel in concrete. The mechanism for this slow down is not well understood but it has been hypothesized that FRP serves as a barrier to the ingress of chloride, moisture, and oxygen that sustain electrochemical corrosion of steel.

This dissertation presents results from an experimental study that determined the oxygen permeation rates of materials used in infrastructure repair. In the study, the oxygen permeation constants for epoxy, carbon and glass fiber laminates, concrete, epoxy-concrete and FRP-concrete systems were determined and a method developed to …

Biodegradation Of Bisphenol-A And 17b-Estradiol In Soil Mesocosms Under Alternating Aerobic/Anoxic/Anaerobic Conditions, Won-Seok Kim

USF Tampa Graduate Theses and Dissertations

Soil-aquifer treatment (SAT) has been proposed as a method for reusing treated municipal wastewater. SAT is characterized by alternating cycles of aerobic and anaerobic conditions in the subsurface, in response to alternating cycles of flooding and drainage of a surface impoundment. It is not yet known how these alternating redox conditions affect the removal of potentially harmful endocrine-disrupting compounds (EDCs) from treated effluent.

The overall objective of my doctoral research is to determine the fate of EDCs in alternating aerobic/anoxic/anaerobic conditions under simulated SAT conditions. To assess the fate of EDCs in simulated SAT conditions, I first had to develop …

Operational Performance Evaluation Of Four Types Of Exit Ramps On Florida's Freeways, Linjun Lu

USF Tampa Graduate Theses and Dissertations

This research focuses primarily on the analysis of exit ramp performance related to safety and operations. The safety analysis focuses on the impacts of different exit ramp types for freeway diverge areas and different factors contributing to the crashes that occur on the exit ramp sections. The operational analysis is based mainly on simulations by TSIS-CORSIM. Different ramp effects and guidance for selecting optimal exit ramp type are concluded. Issues related to ramp sections and crossroad sections are also demonstrated. Minimum ramp length and minimum distance between ramp terminal and downstream or upstream intersections are calculated. The operational analysis was …

Effectiveness Of In-Line Chlorination Of Gravity Flow Water Supply In Two Rural Communities In Panama, Kevin Orner

USF Tampa Graduate Theses and Dissertations

It is well established that water quality is directly linked to health. In-line chlorination is one technology that can be used in the developing world to potentially inactivate pathogens and improve water quality. The purpose of this study was to determine the effectiveness of the Panamanian Ministry of Health's in-line PVC chlorinator under three different operating conditions in a rural water supply system. Free and total chlorine were measured entering the storage tank, leaving the storage tank, and at three households along the transmission line of the water system in the two rural indigenous communities of Calabazal and Quebrada Mina …

Use Of Innovative Computer Technology And Optical Texture Properties In The Analysis Of Pavement Digital Images, Saumya Priyadari Amarasiri

USF Tampa Graduate Theses and Dissertations

Digital image based automated pavement crack detection and classification technology has seen vast improvements in the recent years. In spite of these developments, although pavement crack lengths and widths can be evaluated using state-of-the-art software with a reasonable accuracy, no reported evidence is found in extending this technology to evaluate crack depths. Hence a preliminary study was carried out to model the digital image formation of cracked concrete pavements based on the Bidirectional Reflection Distribution Function. It was revealed that a definitive theoretical relationship exists among the crack widths and depths and the maximum pixel intensity contrasts in the images …

Restoration Of Displaced Cast-In-Place Concrete Slabs On Grade With The Use Of The Isb-07 Subsurface Support Bracket, Jose Carlos Busquets

USF Tampa Graduate Theses and Dissertations

The restoration of foundations of residential and light commercial structures that have been affected by differential displacement resulting from problematic soil conditions has been an ongoing issue since early times. In Florida, the issue of structures being affected by subsidence of soils related to sinkhole activity has been a problem that has gained more interest and exposure within the last 20 years. Structures affected by sinkholes have been historically addressed by remediating the soil mechanism which caused the structure to displace and then structurally addressing the portions of the structure that have displaced with steel underpins installed on the foundation. …

Modeling Roadside Safety Hazards To Predict Annual Crash Cost To Encroaching Vehicles In Rural Road Networks, Isidro Delgado

USF Tampa Graduate Theses and Dissertations

Roadside crashes account for a large portion of total fatal crashes that occur annually in the United States. About 30% of those fatalities are the result of single vehicle run-off-road crashes. A large proportion of these fatal crashes occur in rural roads when vehicles depart from the travel lane and collide with trees or other roadside safety hazards. Many of these run-off-road accidents occur in local roads that carry traffic volumes between 1,000 and 20,000 vehicles per day. Many of these roads are part of the jurisdiction of county authorities faced with the dilemma of having too many "potentially dangerous" …

Advances In Fiber Reinforced Polymer Repair Incorporating Cathodic Protection, Julio Ivan Aguilar

USF Tampa Graduate Theses and Dissertations

This dissertation presents findings from two disparate research projects relating to the cathodic protection (CP) of piles supporting bridge elements. The first was a proof of concept study for developing a new hybrid pile repair system incorporating embedded sacrificial zinc anodes within a fiber reinforced polymer (FRP) wrap. The second was to develop and remotely monitor the performance of magnesium anodes protecting steel Hpiles supporting two bridges in Florida.

The hybrid FRP-CP system involved a proof-of-concept laboratory study to refine pressure / vacuum bagging systems for pile repair and to quantify the improvement in the FRP concrete bond. Two different …

Thermal Integrity Profiling Instrumentation Development, Byron Keith Anderson

USF Tampa Graduate Theses and Dissertations

This thesis has shown that the development of the instrumentation necessary to provide in-situ thermal imaging for the determination of homogeneity of concrete is theoretically sound.

Drilled shafts are large diameter underground cast-in-place columns that necessarily rely on sound integrity to properly withstand imposed loadings. As a by-product of the most common construction techniques, the entire process is often completely blind whereby the excavation and concreting processes are conducted beneath the surface of the water table (or slurry level). This results in an inability to inspect the final product and in many cases allows anomalous inclusions (soil cave-ins, slurry pockets, …

Safety Evaluation Of Roadway Lighting Illuminance Levels And Its Relationship With Nighttime Crash Injury Severity For West Central Florida Region, Enrique Gonzalez-Velez

USF Tampa Graduate Theses and Dissertations

The main role of roadway lighting is to produce quick, accurate and comfortable visibility during nighttime conditions. It is commonly known that good lighting levels enable motorists, pedestrians and bicyclists to obtain necessary visual information in an effective and efficient manner. Many previous studies also proved that roadway lighting minimizes the likelihood of crashes by providing better visibility for roadway users.

Appropriate and adequate roadway lighting illuminance levels for each roadway classification and pedestrian areas are essential to provide safe and comfortable usage. These levels are usually provided by national, or local standards and guidelines. The Florida Department of Transportation …

Comparison Of Safety Performance By Design Types At Freeway Diverge Areas And Exit Ramp Sections, Hongyun Chen

USF Tampa Graduate Theses and Dissertations

The primary objective of the study is to evaluate the safety performance of different freeway exit types used in current practical designs. More specific, the research objectives include the following two parts: 1) to compare the safety performance of different design types at freeway diverge areas and exit ramp sections; and 2) to identify the impact factors contributing to the crashes happening at these two specific segments.

The study area includes four subjects, the freeway widely-spaced diverge areas; the freeway closely-spaced diverge areas; the left-side off-ramps and the exit ramp sections. For the freeway diverge areas, design types were defined …

Modeling And Predicting Taxi Times At Airports, Arjun Chauhan

USF Tampa Graduate Theses and Dissertations

This research aims at providing methods in analyzing and estimating the taxi times of aircraft at airports, which are expected to be an important element for reducing taxiing delay and consequent excess fuel consumption and environmental costs. The proposed model involves a set of regression equations to model the taxi-out and taxi-in times at airports. The estimated results can be used to calculate the nominal taxi times, which are essential measures for evaluating the taxiing delays at airports. Given the outcomes of the regression model, an iterative algorithm is developed to predict taxi times. A case study at LGA shows …

The Green And Ampt Infiltration Model Accounting For Air Compression And Air Counterflow In The Shallow Water Table Environment: Laboratory Experiments, Yuliya Lukyanets

USF Tampa Graduate Theses and Dissertations

Water infiltration into the unsaturated zone especially in a shallow water table environment is affected by air compression ahead of the wetting front and air counterflow. Neglecting air compression in infiltration modeling can overestimate infiltration and infiltration rates, whereas not accounting for air counterflow can underestimate infiltration and infiltration rates due to unrealistic buildup of air pressure resistance ahead of the wetting front. A method, derived on the basis of the Green and Ampt (1911) infiltration model, is introduced to simulate air compression and air counterflow during infiltration into a shallow water table. The method retains the simplicity of the …

Env Engineering Engagement, Maya Trotz

Service-Learning Syllabi

No abstract provided.

Enhancement Of Predictive Capability Of Transit Boardings Estimation And Simulation Tool (Tbest) Using Parcel Data: An Exploratory Analysis, Tejsingh Rana

USF Tampa Graduate Theses and Dissertations

TBEST is a comprehensive third generation transit demand forecasting model, developed by the FDOT Public Transit Office (PTO) to help transit agencies in completing their Transit Development Plans (TDPs). The on-going project funded by FDOT, related to TBEST, aims at further enhancing the capabilities of the TBEST model based on additional opportunities identified by the research team. The project focuses on enhancing TBEST’s capabilities in following areas: 1) Improving the precision of socio- demographic data by using property appraisal data (parcel data) and, 2) Improving the quality of data regarding trip attraction. Based on the improvement areas, this study aims …

An Analysis Of The Travel Patterns And Preferences Of The Elderly, Sujan Sikder

USF Tampa Graduate Theses and Dissertations

The number of elderly is increasing; to meet their transportation needs, it is important to clearly understand their travel patterns and preferences. Since travel patterns and preferences depend on socio-demographic and other factors, it is essential to identify these factors first to understand the travel behavior of the elderly. The main purpose of this thesis is to analyze the travel patterns and preferences of the elderly age 65 and above using 2009 National Household Travel Survey (NHTS) data. This thesis presents a detailed descriptive analysis of 2009 NHTS data to understand the travel patterns of the elderly. Along with a …

A Roof Runoff Strategy And Model For Augmenting Public Water Supply, Robert Carnahan

USF Tampa Graduate Theses and Dissertations

Water is the essential resource that is becoming extremely scarce worldwide. The 21st century will further stress all available water resources through the growth and expansion of developing nations. It is not only the quantity of cheap water that is being depleted, but the quality of these waters is being endangered. Florida is an example where rapid development and an exploding population are competing for shrinking groundwater resources. Current water use does not address the use of alternative supplies and reuses in the United States.

The objective of this research was to determine a strategy for augmenting existing water supplies …

Ecotourism And Water Quality: Linking Management, Activities And Sustainability Indicators In The Caribbean, Ken Darrie Thomas

USF Tampa Graduate Theses and Dissertations

Ecotourism from its genesis and founding theories has been set out to conserve and preserve the environment through sustainable operation that includes surrounding communities in efforts to reduce their poverty levels. Over the years ecotourism has been hypothesized to have departed from this ideal with several researchers, through social, qualitative analyses, have said that these non-sustainable ecotourism operations are simply due to poor management. This work sought to test this central hypothesis as a first approach to quantitatively linking ecotourism activities to management with surface water quality as the key indicator of sustainable ecotourism as a complex system through systems …

Polarization Of Galvanic Point Anodes For Corrosion Prevention In Reinforced Concrete, Margareth Dugarte

USF Tampa Graduate Theses and Dissertations

The polarization performance of two types of commercial galvanic point anodes for protection of reinforced steel around patch repairs was investigated. Experiments included measurement of the polarization history of the anode under constant current impressed by galvanostatic circuits and in reinforced concrete slabs. The tests revealed, for both types of anodes, a potential-current function (PF) indicating relatively little anodic polarization from an open circuit potential at low current levels, followed by an abrupt increase in potential as the current approached an apparent terminal value. Aging of the anodes was manifested by a continually decreasing current output in the concrete tests, …

Mercury In The Environment: Field Studies From Tampa, Bolivia, And Guyana, Joniqua A'Ja Howard

USF Tampa Graduate Theses and Dissertations

Tampa (US), Guyana (SA), and Bolivia (SA), are geographically, socially, economically, and politically unique which make them ideal sites to study issues of mercury and sustainability. Mercury’s innate ability to bioaccumulate and biomagnify in aquatic and terrestrial ecosystems poses a severe threat to both human and environmental health. The most vulnerable populations affected by mercury consumption include coastal communities, children, women of child-bearing age, the indigenous poor and persons with high environmental/occupational exposure factors. Communities in the regions of Florida, Bolivia, and Guyana whose diets are high in fish and are environmentally/occupationally exposed to mercury may be at a higher …

Evaluation Of Unknown Foundations, Ronald W. Florkowski

USF Tampa Graduate Theses and Dissertations

In recent years, bridge foundations have been in the spotlight throughout the nation. Bridges built over running water are susceptible to erosion or scour around their foundations. The reduction in load capacity to piers and abutments pose a safety risk to highway motorists. It has become necessary for engineers to examine and monitor these "scour critical" bridges. The difficulty arises with subsurface foundations of which very little is known about their construction. Hence, the methods applied to analyzing "Unknown Foundations" have become a necessary topic of research.

This thesis explores a method to determine foundation lengths. Similar to Sonic Echo …

Effect Of Tricalcium Silicate Content On Expansion In Internal Sulfate Attack, Troy T. Whitfield

USF Tampa Graduate Theses and Dissertations

The purpose of this study was to determine the cementitious parameters and placement temperature that impact internal sulfate attack in concrete. Concrete structures make up a large percentage of the infrastructure and multifamily housing. Durability is very important. Cements can be formulated to reduce the impact of external environmental exposure such as high salinity from marine environments or high sulfate levels from soils or surface waters. Concrete is also subject to internal attack such as alkali aggregate reaction, (AAR), and delayed ettringite formation, (DEF). This study focused on some of the cement chemistry issues that determine susceptibility of cement to …

A Damage Assessment And Wind Loading Analysis Of Residential Structures Built Post-1996 In Punta Gorda In The Wake Of Hurricane Charley, James Newberry

USF Tampa Graduate Theses and Dissertations

One of the communities in the path of Hurricane Charley as it came ashore

August 13, 2004, was Punta Gorda, recording gusts up to 145 mph. This project

utilizes aerial photos taken approximately 10 days after the storm battered the

area, using a digital photography program. Focusing on the one-story residential

structures (houses) of the Punta Gorda area, a damage assessment could be

made of the area’s homes, and how they stood up to the storm. This study

focused further on homes built after major changes to the local/state building

codes went into effect (starting in 1996) after the devastation …