Civil Engineering Commons^™

Analysis Of Passive Louver Shading Systems And Impact On Interior Environment, Cory Joseph Brennan

Masters Theses

An installed passive louver shading systems can affect the heating, cooling, and lighting loads of any building, by altering the amount of solar energy, in the form of light and heat, from entering. The benefits of a louver system are derived from the application of solar geometry incident on the site and the climate within the area. By optimizing a passive louver system's design parameters, a building can reduce the total annual energy consumption due to artificial heating, cooling loads and artificial lighting. This research has implemented simulation modeling software, Energy Plus, to predict the effect of passive louver shades …

Head Ejection During Barrier Impacts, Scott K. Rosenbaugh, Ronald K. Faller, Dean L. Sicking

Department of Civil and Environmental Engineering: Faculty Publications

During oblique vehicular impacts with longitudinal barriers, an occupant’s head is often ejected out of a side window. When this occurs, the occupant’s head can contact the barrier or an object attached thereto. This impact event, often termed head slap, normally produces a serious injury or fatality. Roadside barriers and any attached hardware should be designed with sufficient offset at the top to preclude head slap for most impact conditions. The goal of this study was to identify the extent of head ejection that can be expected during high-speed crashes with longitudinal barriers. High-speed videos of full-scale vehicle crash tests …

Drop Weight Testing On Sandwich Panels With A Novel Thermoplastic Core Material, Christopher Y. Tuan

Department of Civil and Environmental Engineering: Faculty Publications

A series of drop weight tests were conducted to evaluate the dynamic flatwise compression strength and flexural strength of sandwich panels with a novel core structure. This sandwich core material, known as Norcore, consists of interconnected cells in a unique configuration of truncated pyramid with sloping cell walls. Core materials made of thermoplastic including virgin Lexan, polycarbonate, polycarbonate regrind, high-impact polystyrene, and acrylonitrile butadiene styrene were tested. The test results showed that these sandwich panels have good strength as well as energy absorption capacities.

Evaluation Of Ice-Melting Capacities Of Deicing Chemicals, B. M. Gerbino-Bevins, Christopher Y. Tuan, M. Mattison

Department of Civil and Environmental Engineering: Faculty Publications

Common deicing chemicals include sodium chloride, magnesium chloride, calcium chloride, calcium magnesium acetate, potassium acetate, potassium formate, and corn or beet-based deicer solution. Liquid deicers are commonly used for pre-wetting road salt, sand or other solid deicers, or mixed with salt brine as liquid deicer. Although manufacturers provide performance data under specific conditions, a standardized test is very much needed. Samples of sodium chloride, magnesium chloride, calcium chloride, potassium acetate, and beet juice-based chemical deicers were selected for performance evaluation. The SHRP Ice-Melting Capacity Test has been used in many research projects, but the results do not always correlate well …

Bs News January/February

Building Services Engineering

No abstract provided.

Shear And Fracture Behavior Of High-Volume Fly Ash Reinforced Concrete For Sustainable Construction, Carlos Andres Ortega Ordonez

Doctoral Dissertations

"Concrete is the most widely used man-made material on the planet. Unfortunately, producing Portland cement generates carbon dioxide (a greenhouse gas) at roughly a pound for pound ratio. High-volume fly ash (HVFA) concrete- concrete with at least 50% of the cement replaced with fly ash - offers a potential "green" solution. However, because it is still relatively new and has some disadvantages, there are still many questions that need to be answered. Most research to date has consisted only of the evaluation of the strength and durability of HVFA concrete mixtures, while only a limited number of studies have implemented …

Prediction And Performance Of Single Piles In Clay Soils Under Vibratory Loadings, Domenica Cambio

Doctoral Dissertations

"This study developed a model for predicting the response, in terms of amplitude versus frequency of single piles under lateral vibratory loadings embedded in clay or fine silty soils. The model incorporates frequency dependent parameters and the effects of soil non-linearity through the relationship between soil shear modulus and damping with strain. A computer program, Dyna5, was used to generate the computed response of single piles using the Novak and El-Shamouby (1983) approach. Soil non-linearity was accounted for by incorporating spline interpolation routine into Dyna5. Sliding and coupled rocking vibrations were addressed. The computed responses were predicted and compared with …

Bond, Transfer Length, And Development Length Of Prestressing Strand In Self-Consolidating Concrete, Krista Beth Porterfield

Masters Theses

"Due to its economic advantages, the use of self-consolidating concrete (SCC) has increased rapidly in recent years. However, because SCC mixes typically have decreased amounts of coarse aggregate and high amounts of admixtures, industry members have expressed concerns that the bond of prestressing strand in SCC may be compromised. While the bond performance of prestressing strand in a new material such as SCC is an important topic requiring investigation, the results are only applicable if the research is completed on strands with similar bond quality as the strands used in the field. Therefore, the objectives of this research program were …

The Repair Of Laterally Damaged Concrete Bridge Girders Using Carbon Fiber Reinforcing Polymers (Cfrp), Matthew Kent Graeff

UNF Graduate Theses and Dissertations

In recent years the use of carbon fiber reinforcing polymers (CFRP) to repair damaged structural components has become more accepted and practiced. However, the current reference for designing FRP systems to repair and strengthen reinforced concrete (RC) and prestressed concrete (PSC) girders has limitations. Similarly, very few resources address solutions for the debonding problem associated with CFRP laminates or the use of CFRP laminates to repair structural members with pre-existing damage. The included experimental program consists of testing both RC and PSC girders with simulated lateral damage and CFRP repairs. A total of 34 RC beams were statically tested under …

Preliminary Feasibility Of Transporting And Geologically Sequestering Carbon Emissions In The Florida Pan-Handle, Brandon Keith Poiencot

UNF Graduate Theses and Dissertations

According to the United States Department of Energy, fossil-fueled power plants account for 78% of stationary source CO2 emission in the United States and Canada. This has led electric utilities across the globe to research different alternatives for energy. Carbon sequestration has been identified as a bridge between fossil fuels and clean energy.

This thesis will present research results regarding the transportation costs of CO2 and the suitability of geology in the Florida Pan-Handle for sequestration infrastructure. The thesis will utilize various evaluation tools including GIS, numerical models, and optimization models.

Analysis performed for this thesis and review of published …

Discrete Fiber-Reinforced Polyurea Systems For Infrastructure Strengthening And Blast Mitigation, Natalia L. Carey

Doctoral Dissertations

"The research presented in this dissertation focused on evaluating the effectiveness of various blast mitigation materials and coating technologies to be used for enhancing blast resistance of structural members. Mechanical properties and blast mitigation performance of different discrete fiber-reinforced polyurea (DFRP) systems were investigated through experimental and analytical work. Four technical papers discuss the research efforts conducted within this dissertation.

The first paper examined the development and characterization of different DFRP systems for infrastructure strengthening and blast retrofit. The behavior of various systems which consisted of chopped E-glass fibers discretely integrated in with the polyurea matrix was evaluated through coupon …

Corrosion Of Post-Tensioned Tendons Repaired With Dissimilar Grout, Juan Carlos Rafols

UNF Graduate Theses and Dissertations

A failure associated with steel corrosion was identified in early 2011 in a bridge external post-tensioned tendon, approximately eight years after construction. Large voids in the grout and pockets of non-homogeneous material were identified. The non-homogeneous grout was characterized by high moisture content, and in most cases, the chloride content was lower than conservative threshold values. The non-homogeneous grout also had high pH and high content of sulfates (approximately in the range of 10,000-ppm). As a result, there was an interest in the study of possible corrosion development in repaired systems in which the affected tendons have been re-grouted with …

Flexural Behavior Of Laterally Damaged Full-Scale Bridge Girders Through The Use Of Carbon Fiber Reinforced Polymers (Cfrp), Nicholas James Alteri

UNF Graduate Theses and Dissertations

ABSTRACT

The repair and strengthening of concrete bridge members with CFRP has become increasingly popular over recent years. However, significant research is still needed in order to develop more robust guidelines and specifications. The research project aims to assist with improving design procedures for damaged concrete members with the use of CFRP.

This document summarizes the analysis and testing of full-scale 40’ foot long prestressed concrete (PSC) bridge girders exposed to simulated impact damage and repaired with carbon fiber reinforced polymers (CFRP) materials. A total of five AASHTO type II bridge girders fabricated in the 1960’s were taken from an …

A Progressive Collapse Evaluation Of Steel Structures In High Temperature Environment With Optical Fiber Sensors, Ying Huang

Doctoral Dissertations

"In the process of a progressive failure of steel structures in a post-earthquake fire, real-time assessment and prediction of structural behaviors are of paramount significance to an emergency evacuation and rescue effort. However, existing measurement technologies cannot provide the needed critical data such as large strains at high temperature. To bridge this gap, a novel optical fiber sensor network and an adaptive multi-scale finite element model (FEM) are proposed and developed in this study. The sensor network consists of long period fiber gratings (LPFG) sensors and extrinsic Fabry-Perot interferometer (EFPI) sensors or their integration. Each sensor is designed with a …

Characterization Of Soil Variability For Reliability-Based Design, Sitenikechukwu Onyejekwe

Doctoral Dissertations

"A very carefully planned Missouri-wide field exploration and laboratory investigation program, with a focus on fine-grained soils, was executed with the aim of characterizing the variability of geotechnical parameters statistically with a view to increasing the use of reliability-based design (RBD) among geotechnical engineers. Geotechnical parameters were characterized in terms of both their first and second statistical moments and their coefficient of variation (COV). Their probability distributions and their scale of fluctuation, θ, were also determined. Correlations between difficult-to-obtain parameters and more easily-obtained parameters were developed and the degree of fit of study data to published empirical correlations was investigated. …

Characterization Of Expanded Polystyrene (Eps) And Cohesive Soil Mixtures, Nicholas Thomas Rocco

Doctoral Dissertations

"Soils modified with expanded polystyrene (EPS) particulates could be used as lightweight fill in a variety of installations including slopes for improved stability, embankments over compressible soils, and to reduce earth pressures next to structures. The addition of low density EPS particulates into soil has a large effect on the mass and volumetric characteristics of these mixtures and their influence on mechanical properties is scarce in the literature. A laboratory characterization program using clay mixed with EPS particulates was conducted for different dosages of EPS. Soils were modified with up to 1.5% EPS by mass, which corresponds to approximately 45% …

Nitrification Performance Of Activated Sludge Under Low Dissolved Oxygen Conditions, Guoqiang Liu

Doctoral Dissertations

"The combined effects of solids retention time (SRT) and dissolved oxygen (DO) concentration on nitrification, nitrifying bacterial communities, and aeration needs in the activated sludge process were studied. Nitrification was almost completed in the 10, 20, and 40-day SRT reactors with a minimum DO of 0.37, 0.25, and 0.16 mg/L, respectively. Under long-term low DO conditions, the endogenous decay of nitrifiers was slowed down and then nitirfier biomass concentration increased, thereby reducing the adverse effect of low DO on nitrification. Under long-term low DO conditions, the oxygen affinity of nitrite-oxidizing bacteria (NOB) increased significantly and as a result, NOB became …

Behavior Of Staged Externally Bonded Carbon Fiber Reinforced Polymer Sheets For Improved Ductility, Laura Marie Rathe

Masters Theses

"Fiber reinforced polymers (FRP) has become increasingly used for the retrofit of aging structures for increased lifespans and for the rapid repair of damaged structures. It has many advantageous such as ease in rapid installation, high strength-to-weight ratio, and corrosion resistance. The main disadvantage of the material is brittle behavior with little warning of impending failures. The main objective of this study is to develop a new system of FRP that exhibits a more ductile behavior. To achieve this objective, separate sheets of FRP were applied at various staged levels and thus engaged at different loads. Ductile behavior was evaluated …

Effects Of High Volume Fly Ash And Powder Activators On Plastic And Hardened Concrete Properties, Drew Alexander Davis

Masters Theses

This study was performed to examine the effects of high volumes of Class C fly ash modified by powder activators upon the plastic and hardened properties of concrete. In a companion study, five Missouri area cements and five Class C fly ashes were examined for incompatibilities, with the most and least reactive combinations being scaled up to full scale concrete testing. Two baseline concrete mixtures were examined, the only difference in mixtures being the sources of portland cement and fly ash. Fly ash replacement was examined at 50% and 70% replacement (by total cementitious mass). Three powder activators were used …

Distribution Analysis Of Freight Transportation With Gravity Model And Genetic Algorithm, Jun Duanmu, Peter Foytik, Asad Khattak, R. Michael Robinson

VMASC Publications

The application of a gravity model in freight modeling work on both short-haul and long-haul trips is discussed. A commodity-based gravity model was developed to assess the distribution of freight by long-haul trucks in southeastern Virginia. Although gravity models have been used extensively in transportation studies, little work has been done to address the special characteristics of freight transportation, such as the definition of friction factors and the differences between long-haul and short-haul trips. Results of a recent study of these and similar problems provide valuable insight into freight distribution modeling. A new calibration method that used a genetic algorithm …