Open Access. Powered by Scholars. Published by Universities.®

Civil and Environmental Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

University of Central Florida

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 571 - 600 of 627

Full-Text Articles in Civil and Environmental Engineering

Structural Condition Assessment Of Prestressed Concrete Transit Guideways, Robert Zachary Shmerling Jan 2005

Structural Condition Assessment Of Prestressed Concrete Transit Guideways, Robert Zachary Shmerling

Electronic Theses and Dissertations

Objective condition assessment is essential to make better decisions for safety and serviceability of existing civil infrastructure systems. This study explores the condition of an existing transit guideway system that has been in service for thirty-five years. The structural system is composed of six-span continuous prestressed concrete bridge segments. The overall transit system incorporates a number of continuous bridges which share common design details, geometries, and loading conditions. The original analysis is based on certain simplifying assumptions such as rigid behavior over supports and simplified tendon/concrete/steel plate interaction. The current objective is to conduct a representative study for a more …

Go to article

Right Turn Split: A New Design To Alleviate Weaving On Arterial Streets, Khaled Shaaban Jan 2005

Right Turn Split: A New Design To Alleviate Weaving On Arterial Streets, Khaled Shaaban

Electronic Theses and Dissertations

While weaving maneuvers occur on every type of roadway, most studies have focused on freeway maneuvers. Weaving occurring on non-freeway facilities, such as arterial streets, can cause significant operational problems. Arterial streets weaving typically occur when vehicles coming from a side street at an upstream intersection attempt to enter the main street from one side to reach access points on the opposite site at a downstream intersection by crossing one or more lanes. This dissertation investigates the type of problems occurring on arterial streets due to the weaving movements and recommends a new design to alleviate weaving on arterial streets. …

Go to article

Assessing Crash Occurrence On Urban Freeways Using Static And Dynamic Factors By Applying A System Of Interrelated Equations, Rajashekar Pemmanaboina Jan 2005

Assessing Crash Occurrence On Urban Freeways Using Static And Dynamic Factors By Applying A System Of Interrelated Equations, Rajashekar Pemmanaboina

Electronic Theses and Dissertations

Traffic crashes have been identified as one of the main causes of death in the US, making road safety a high priority issue that needs urgent attention. Recognizing the fact that more and effective research has to be done in this area, this thesis aims mainly at developing different statistical models related to the road safety. The thesis includes three main sections: 1) overall crash frequency analysis using negative binomial models, 2) seemingly unrelated negative binomial (SUNB) models for different categories of crashes divided based on type of crash, or condition in which they occur, 3) safety models to determine …

Go to article

Infrared Thermography And High Accuracy Gps For Automated Asphalt Crack Detection, Tarek M. Abdel-Monem Jan 2005

Infrared Thermography And High Accuracy Gps For Automated Asphalt Crack Detection, Tarek M. Abdel-Monem

Electronic Theses and Dissertations

Roads are major public assets. The USA spends billions of dollars each year on road construction and maintenance. To keep these roads in a healthy condition and for better planning and allocation of maintenance budgets, knowledge of distressed locations is needed. Roads develop cracks when they are subjected to stresses that exceed their designed criteria or their materials properties. Early detection and repair of cracks has proven to be the most cost-effective strategy in limiting the damage to roads and reducing expenditures. Various methodologies of crack detection were developed and significant techniques were made in the last few years. One …

Go to article

Effects Of Bedding Void On Internal Moment Increase In Concrete Pipes, Jad Kazma Jan 2005

Effects Of Bedding Void On Internal Moment Increase In Concrete Pipes, Jad Kazma

Electronic Theses and Dissertations

Large diameter concrete pipes have been used in many areas of central Florida to carry pressured sewage flow. These pipes have been typically located at six feet below finished roadway elevation, and ranges in diameter from thirty six to sixty inches. The water table is typically located at shallow depth below finished roadway elevation, and generally fluctuates between five to ten feet depending on the relative roadway elevation to mean sea level. These pipes are under pressure when carrying the sewage flow, but return to normal atmospheric pressures when the flow stops. Since the water table encases most of the …

Go to article

Evaluating Ramp Metering And Variable Speed Limits To Reduce Crash Potential On Congested Freeways Using Micro-Simulation, Albinder Dhindsa Jan 2005

Evaluating Ramp Metering And Variable Speed Limits To Reduce Crash Potential On Congested Freeways Using Micro-Simulation, Albinder Dhindsa

Electronic Theses and Dissertations

Recent research at UCF into defining surrogate measures for identifying crash prone conditions on freeways has led to the introduction of several statistical models which can flag such conditions with a good degree of accuracy. Outputs from these models have the potential to be used as real-time safety measures on freeways. They may also act as the basis for the evaluation of several intervention strategies that might help in the mitigation of risk of crashes. Ramp Metering and Variable Speed Limits are two approaches which have the potential of becoming effective implementation strategies for improving the safety conditions on congested …

Go to article

Hydrogen Sulfide Flux Measurements And Dispersion Modeling From Constr, Sangho Eun Jan 2004

Hydrogen Sulfide Flux Measurements And Dispersion Modeling From Constr, Sangho Eun

Electronic Theses and Dissertations

Odor problems are a common complaint from residents living near landfills. Many compounds can cause malodorous conditions. However, hydrogen sulfide (h2s) has been identified as a principal odorous component from construction and demolition (c&d)debris landfills. Although several studies have reported the ambient concentrations of h2s near c&d landfills, few studies have quantified emission rates of h2s. The most widely used and proven technique for measuring gas emission rates from landfills is the flux chamber method. Typically the flux chamber is a cylindrical enclosure device with a spherical top which limits the gas emission area. Pure zero grade air is introduced …

Go to article

Nitrification Investigation And Modeling In The Chloraminated Drinking Water Distribution System, Suibing Liu Jan 2004

Nitrification Investigation And Modeling In The Chloraminated Drinking Water Distribution System, Suibing Liu

Electronic Theses and Dissertations

This dissertation consists of five papers concerning nitrification in chloraminated drinking water distribution systems in a one and a half year field study. Seven finished waters were produced from different treatment processes and distributed to eighteen pilot distribution systems (PDSs) that were made pipes taken from actual distribution systems. Unlined cast iron (UCI), galvanized steel (G), lined cast iron (LCI), and PVC pipes were used to build the PDSs. All finished waters were stabilized and chloraminated before entering the PDSs. This dissertation consists of five major parts. (1) System variations of nitrates, nitrites, DO, pH, alkalinity, temperature, chloramine residuals and …

Go to article

Evaluation Of The Impacts Of Its Information Strategies On I-4 Corridor, Yueliang Zuo Jan 2004

Evaluation Of The Impacts Of Its Information Strategies On I-4 Corridor, Yueliang Zuo

Electronic Theses and Dissertations

This study evaluated the impacts of ITS information strategies under incident conditions in Interstate 4 (I-4) corridor of Orlando. The analysis was performed using DYNASMART-P software package. The ITS information strategies range from pre-trip information, en-route information, and variable message signs. Simulation covered one hour during the morning peak period. The impacts of ITS information strategies on mobility were evaluated by simulating the performance of various ITS information components (pre-trip information, en-route information, and variable message signs) under incident conditions for the I-4 corridor and comparing the results with the corresponding scenarios in the absence of these components. The traffic …

Go to article

Analysis Of Type And Severity Of Traffic Crashes At Signalized Intersections Using Tree-Based Regression And Ordered Probit Models, Joanne Marie Keller Jan 2004

Analysis Of Type And Severity Of Traffic Crashes At Signalized Intersections Using Tree-Based Regression And Ordered Probit Models, Joanne Marie Keller

Electronic Theses and Dissertations

Many studies have shown that intersections are among the most dangerous locations of a roadway network. Therefore, there is a need to understand the factors that contribute to traffic crashes at such locations. One approach is to model crash occurrences based on configuration, geometric characteristics and traffic. Instead of combining all variables and crash types to create a single statistical model, this analysis created several models that address the different factors that affect crashes, by type of collision as well as injury level, at signalized intersections. The first objective was to determine if there is a difference between important variables …

Go to article

Investigation Of Ground Penetrating Radar For Detection Of Leaking Pipelines Under Roadway Pavements And Development Of Fiber-Wrapping Repair Technique, Pedro F. Suarez Jan 2004

Investigation Of Ground Penetrating Radar For Detection Of Leaking Pipelines Under Roadway Pavements And Development Of Fiber-Wrapping Repair Technique, Pedro F. Suarez

Electronic Theses and Dissertations

Nowadays, it has become a common practice to observe urban roadways undergo severe distress characterized by substantial depressions. In some cases, these pavement depressions are caused by leakages in the connecting joints of sewage pipelines laid beneath the roadway pavement. Manual inspection of pipe leakages has become costly and complex since sewage pipes with relative small diameters do not allow inspection from inside and digging may be required. On the other hand, pipes with large diameters, in which inspection can be made from pipe interior, inspector can not remain inside of the pipe for long periods of time because of …

Go to article

Modeling Of Membrane Solute Mass Transfer In Ro/Nf Membrane Systems, Yu Zhao Jan 2004

Modeling Of Membrane Solute Mass Transfer In Ro/Nf Membrane Systems, Yu Zhao

Electronic Theses and Dissertations

Five articles describing the impact of surface characteristics, and development of mass transfer models for diffusion controlled membrane applications are published in this dissertation. Article 1 (Chapter 3) describes the impact of membrane surface characteristics and NOM on membrane performance for varying pretreatment and membranes during a field study. Surface charge, hydrophobicity and roughness varied significantly among the four membranes used in the study. Membrane surface characteristics, NOM and SUVA measurements were used to describe mass transfer in a low pressure RO integrated membrane system. Inorganic and organic solute and water mass transfer coefficients were systematically investigated for dependence on …

Go to article

Biostability In Drinking Water Distribution Systems Study At Pilot-Scale, Michael Le Puil Jan 2004

Biostability In Drinking Water Distribution Systems Study At Pilot-Scale, Michael Le Puil

Electronic Theses and Dissertations

Biostability and related issues (e.g. nitrification) were investigated for 18 months in 18 pilot distribution systems, under various water quality scenarios. This study specifically investigated the impact of steady-state water changes on HPC levels in chlorinated and chloraminated distribution systems. Chlorination was more effective than chloramination in reducing HPC levels (1-2 log difference). There was a rapid increase in HPC corresponding to the change in steady-state water quality, which was observed in all PDS. Modeling effort demonstrated that HPC levels reached a maximum within five days after water quality change and return to initial level ten days after the change. …

Go to article

Effects Of The Soil Properties On The Maximum Dry Density Obtained Fro, Andres Arvelo Jan 2004

Effects Of The Soil Properties On The Maximum Dry Density Obtained Fro, Andres Arvelo

Electronic Theses and Dissertations

In the construction of highways, airports, and other structures, the compaction of soils is needed to improve its strength. In 1933 Proctor developed a laboratory compaction test to determine the maximum dry density of compacted soils, which can be used for specifications of field compaction. The Compaction of soils is influenced by many factors, the most common are the moisture content, the soil type and the applied compaction energy. The objective of this research is the analysis of the maximum dry density values based on the soil classification and characterization. The method of choice in the determination of the maximum …

Go to article

Predicting Air Quality Near Roadway Intersections Through The Applicat, Brian Kim Jan 2004

Predicting Air Quality Near Roadway Intersections Through The Applicat, Brian Kim

Electronic Theses and Dissertations

With substantial health and economic impacts attached to many highway-related projects, it has become imperative that the models used to assess air quality be as accurate as possible. The United States (US) Environmental Protection Agency (EPA) currently promulgates the use of CAL3QHC to model concentrations of carbon monoxide (CO) near roadway intersections. This model uses steady-state and macroscopic methods to model the physical phenomena (e.g., emission rates, atmospheric dispersion, etc.) occurring at intersections. These methods are not straightforward and unintuitive for the users. Therefore, this project investigated the possibility of developing a model that is theoretically more realistic and flexible …

Go to article

Modeling Crash Frequencies At Signalized Intersections In Central Flor, Smitha Kowdla Jan 2004

Modeling Crash Frequencies At Signalized Intersections In Central Flor, Smitha Kowdla

Electronic Theses and Dissertations

A high percentage of highway crashes in the United States occur at intersections. These crashes result in property damage, lost productivity, injury, and even death. Identifying intersections associated with high crash rate is very important to minimize future crashes. The purpose of this study is to develop efficient means to evaluate intersections, which may require safety improvements. The area covered by the analysis in this thesis includes Orange and Seminole Counties and the City of Orlando. The aforementioned counties and city thus represent Central Florida. Each County/City provided data that consisted of signalized intersection drawings that were either in the …

Go to article

Failure Mode Identifications Of Rc Beams Externally Strengthened With, Chris O'Riordan-Adjah Jan 2004

Failure Mode Identifications Of Rc Beams Externally Strengthened With, Chris O'Riordan-Adjah

Electronic Theses and Dissertations

The application of carbon reinforced-fiber polymers (CFRP) to structures is a new development that is still under intense research. However, the rehabilitation or retrofit of damage reinforced concrete members by the external bonding of CFRP is becoming increasingly popular in the construction industry. The objective of the tests presented in this thesis is to study different CFRP designs on the reinforced concrete beams and compare their failure modes. The main goal is to determine the CFRP design on the reinforced concrete beams that result in a progressive and gradual failure mode with enough warning before final failure. Different CFRP designs …

Go to article

Evaluation Of The Potential Benefits To Traffic Operations At A Toll Plaza With Express Etc Lanes, Eric Anthony Gordin Jan 2004

Evaluation Of The Potential Benefits To Traffic Operations At A Toll Plaza With Express Etc Lanes, Eric Anthony Gordin

Electronic Theses and Dissertations

The effectiveness of modifying a conventional toll plaza for implementation of an open road tolling concept with express ETC lanes was evaluated in this thesis. Speed controlled dedicated ETC lanes were replaced with express ETC lanes at the Orlando-Orange County Expressway Authority (OOCEA) University Mainline Toll Plaza. This evaluation was accomplished by utilizing collected field data and simulated scenarios using Toll Plaza SIMulation (TPSIM) software developed by the University of Central Florida. The speed controlled dedicated ETC lanes were located within toll lanes (contained within a toll plaza canopy) with widths ranging between 10 to 14 ft. These types of …

Go to article

Slope Stability Analysis Of Class I Landfills With Co Disposal Of Bios, Mrutyunjay Vajirkar Jan 2004

Slope Stability Analysis Of Class I Landfills With Co Disposal Of Bios, Mrutyunjay Vajirkar

Electronic Theses and Dissertations

Land filling provides a major, safe, and economical disposal route for biosolids and sludges. With an expanding world, the demand for larger and higher capacity landfills is rapidly increasing. Proper analysis and design on such fills have pushed the boundaries of geotechnical engineering practice, in terms of proper identification and assessment of strength and deformation characteristics of waste materials. The engineering properties of Municipal Solid Waste (MSW) with co-disposal of biosolids and sludges with regards to moisture characteristics and geotechnical stability are of utmost importance. Significant changes in the composition and characteristics of landfill may take place with the addition …

Go to article

Effect Of Source Water Blending On Copper Release In Pipe Distribution System: Thermodynamic And Empirical Models, Weizhong Xiao Jan 2004

Effect Of Source Water Blending On Copper Release In Pipe Distribution System: Thermodynamic And Empirical Models, Weizhong Xiao

Electronic Theses and Dissertations

This dissertation focuses on copper release in drinking water. Qualitative and quantitative assessment of Cu and Fe corrosion by process water quality was assessed over one year in a field study using finished waters produced from seven different treatment process and eighteen pilot distribution systems (PDSs) that were made from unlined cast iron and galvanized steel pipes, and lined cement and PVC pipes taken from actual distribution systems. Totally seven different waters were studied, which consisted of three source waters: groundwater, surface, and simulated brackish water designated as G1, S1, and RO. With certain pre-established blending ratios, these three waters …

Go to article

Water Quality Variations During Nitrification In Drinking Water Distribution Systems, David W. Webb Jan 2004

Water Quality Variations During Nitrification In Drinking Water Distribution Systems, David W. Webb

Electronic Theses and Dissertations

This thesis documents the relationship among the major water quality parameters during a nitrification episode. Nitrification unexpectedly occurred in a chloraminated pilot drinking water distribution system practicing with a 4.0 mg/L as Cl2 residual dosed at 4.5:1 Cl2:NH3-N. Surface, ground and sea water were treated and disinfected with monochloramines to produce finished water quality similar to regional utility water quality. PVC, galvanized, unlined cast iron and lined iron pipes were harvested from regional distribution systems and used to build eighteen pilot distribution systems (PDSs). The PDSs were operated at a 5-day hydraulic residence time (HRT) and ambient temperatures. As seasonal …

Go to article

Application Of Absorptive Treatments On Traffic Noise Barriers In Florida, Chin Boon Chua Jan 2004

Application Of Absorptive Treatments On Traffic Noise Barriers In Florida, Chin Boon Chua

Electronic Theses and Dissertations

In this thesis, the parallel barrier analysis feature in the Federal Highway Administration Traffic Noise Model (FHWA TNM), which is based on RAYVERB was used to explore the effects of multiple reflections due to single and parallel barriers and the use of absorptive treatment. Database was developed from the data collected from previous research efforts was used to generate a best fit equation model that can be used as a predetermining tool to determine the magnitude of parallel barrier insertion loss. The best fit equation model was then used to test against measured/model result and TNM prediction results for its …

Go to article

Inelastic Dynamic Behavior And Design Of Hybrid Coupled Wall Systems, Mohamed Hassan Jan 2004

Inelastic Dynamic Behavior And Design Of Hybrid Coupled Wall Systems, Mohamed Hassan

Electronic Theses and Dissertations

A key consideration in seismic design of buildings is to ensure that the lateral load resisting system has an appropriate combination of strength, stiffness and energy dissipation capacity. Hybrid coupled wall systems, in which steel beams are used to couple two or more reinforced concrete shear walls in series, can be designed to have these attributes and therefore have the potential to deliver good performance under severe seismic loading. This research presents an investigation of the seismic behavior of this type of structural system. System response of 12- and 18-story high prototypes is studied using transient finite element analyses that …

Go to article

Location Of Sinkhole Confining Breach Using Groundwater Flow Patterns Derived From Cone Penetration Testing, Natalie Romina Marinuzzi Jan 2004

Location Of Sinkhole Confining Breach Using Groundwater Flow Patterns Derived From Cone Penetration Testing, Natalie Romina Marinuzzi

Electronic Theses and Dissertations

Dynamic forces in the hydrologic cycle move underground water through Florida's carbonate rocks dissolving chemical components of the rocks, leaving behind caves, solution pipes, and other voids that result in a karst terrain. Ravelling is the common subsidence mechanism throughout most of Florida where unconsolidated materials filter downward into voids in the underlying limestone. A cavity in the overburden develops and enlarges over a period of many years. The enlarged cavity is also known as sinkhole. The investigations of sinkhole characteristics and potential involve studying the regional geology, hydrology and mapping historic sinkholes that have occurred in the area. Use …

Go to article

Detection And Evaluation Of Exisiting Pavement System With Brick Base, Karishma Desai Jan 2004

Detection And Evaluation Of Exisiting Pavement System With Brick Base, Karishma Desai

Electronic Theses and Dissertations

At the turn of the century, the City of Orlando initiated the "Neighborhood Horizon Program." This program involved local citizens to help improve their community resources by engaging in a process of planning where the problems associated with the communities were identified. Many residents favored to bring back the brick roads that were overlaid with asphalt concrete to provided better transportation in the mid 1900s. With majority of the neighborhood streets already bricked, removing asphalt ensured safety, served as a technique for slowing traffic, and added to the historical integrity. Since there were no official documentations available that stated the …

Go to article

Degradation Of Halogenated Aliphatic Compounds In Sequential Anaerobic, Scott Hoxworth Jan 2004

Degradation Of Halogenated Aliphatic Compounds In Sequential Anaerobic, Scott Hoxworth

Electronic Theses and Dissertations

The objective of this study was to utilize an alternating anaerobic/aerobic sequence to biologically transform perchloroethylene to non-hazardous end products such as ethylene, CO2 and H2 using a single microbial consortia in a methanogenic and/or a homoacetogenic environment followed by a aerobic methanotrophic environment. Reductive dechlorination of PCE and TCE to cDCE and VC in an anaerobic environment is typically carried out by methanogens, sulfidogens, or homoacetogens but often (e.g. in-situ) leads to an accumulation of daughter compounds (cDCE, VC) which are more toxic than their parent compounds (PCE, TCE). Furthermore, PCE is resistant to degradation in aerobic environments while …

Go to article

Two Dimensional Linear Finite Element Analysis Of Post-Tensioned Beams, Rodolfo Hutchinson Jan 2004

Two Dimensional Linear Finite Element Analysis Of Post-Tensioned Beams, Rodolfo Hutchinson

Electronic Theses and Dissertations

The objective of this research project was to create a Finite Element Routine for the Linear Analysis of Post-Tensioned beams using the program CALFEM® [20] developed at the division of Structural Mechanics in Lund University, Sweden. The program CALFEM and our own made files were written in MATLAB, an easy to learn and user-friendly computer language. The approach used in this thesis for analyzing the composite beam consists in embedding the steel tendons at the exact location where they intersect the concrete parent elements, without moving the concrete parent element nodes. The steel tendons are represented as one dimensional bar …

Go to article

Dewatering Of Biosolids By Sodium Ferrate, Andrea Rios Jan 2004

Dewatering Of Biosolids By Sodium Ferrate, Andrea Rios

Electronic Theses and Dissertations

This study was conducted to evaluate the effectiveness of the liquid form of ferrate for dewatering of biosolids from wastewater treatment facilities. Two different ferrate products prepared using calcium hypochlorite and sodium hypochlorite were used. Samples of anaerobic digested sludge and waste activated sludge with solids content of 2.1% and 0.95 %, respectively were conditioned with both products to evaluate and compare their effectiveness. Centrifugation and filtration of the sludge after conditioning were used. For centrifugation the volume reduction and the turbidity of the supernatant after centrifugation were evaluated. For filtration, the Capillary Suction Time test was used. The optimum …

Go to article

Field Evaluation Of Ultrasound Enhancement Of Permeable Treatment Walls, Aamod Sudhakar Sonawane Jan 2000

Field Evaluation Of Ultrasound Enhancement Of Permeable Treatment Walls, Aamod Sudhakar Sonawane

Retrospective Theses and Dissertations

The objective of this research was to demonstrate the application of ultrasound to field sites having problems with precipitation build up and corrosion. PTW s are passive reactive walls containing zero-valent iron metal for in-situ remediation of contaminated groundwater. However, loss of reactivity over time due to build up of corrosion and other precipitates on the iron surface is a major concern. Ultrasound energy has been established as an effective tool for revitalizing iron surface. This research applied ultrasound energy to a zero-valent iron wall constructed below the ground surface to remove precipitates and iron corrosion, increasing iron reactivity. Two …

Go to article

Nonlinear Modeling Of Concrete-Filled Frp Tubes Using The Finite Element Method, Kenneth T. Zagers Jan 1998

Nonlinear Modeling Of Concrete-Filled Frp Tubes Using The Finite Element Method, Kenneth T. Zagers

Retrospective Theses and Dissertations

Fiber reinforced plastic (FRP) has in recent years emerged as an alternative reinforcement for structural concrete. The properties that make FRP appealing to the construction industry include its resistance to electro-chemical corrosion, high strength-to-weight ratio, and electrical insulation. An efficient use of FRP is in the form of concrete-filled tubes, where the tube not only protects the concrete against environmental factors, but also provides confinement and external reinforcement. Since use of fiber composites for confining concrete is relatively new, analytical work in this area is limited to the models that were originally developed for transverse steel reinforcement. However, it has …

Go to article

First Prev Next Last