Civil Engineering Commons^™

Field Observations And Computer Modeling Of Tornado-Terrain Interaction And Its Effects On Tornado Damage And Path, Nawfal Shihab Ahmed

Graduate Theses and Dissertations

Tornado forces on structures have been a research focus for the past decades, and some comparisons have been made to distinguish between straight boundary layer (SBL) wind and tornado wind forces on specific structures. However, very little attention has been paid to terrain effects on tornado damage and path. Available damage investigation data for four tornado locations (Joplin-2011, Tuscaloosa-2011, Parish-2011 and Mayflower-2014) is utilized to explore terrain effects on tornado damage and path. Google Earth, site visits and aerial images are employed to study the influence of terrain on an extent of damage and path variation. Additionally, a three dimensional …

Development Of The Masw Method For Pavement Evaluation, Benjamin J. Davis

Graduate Theses and Dissertations

The purpose of this research is to establish a recommended procedure for performing multichannel analysis of surface waves (MASW) on pavements as well as evaluating the ability of MASW to detect a change in shear wave velocity as damage in concrete increases. The tests for establishing a recommended procedure for performing MASW on pavements was conducted at five sites at the University of Arkansas Engineering Research Center in Fayetteville, Arkansas. The five sites consisted of three materials: asphalt, concrete, and soil (two sites were on asphalt, two were on concrete, and one was on soil). The methods evaluated at these …

Strengthening Of Lightweight Reinforced Concrete Beams Using Carbon Fiber Reinforced Polymers (Cfrp), Tariq Al Jaafreh

Civil Engineering Theses - Archive

This research aimed to investigate the effect of utilizing “Fiber Reinforced Polymer” (FRP) on the light weight concrete beams. The main hypothesis is that such utilization of the FRP will lead to strengthened lightweight beams. The research that has been done on this relationship is somewhat broad in the scope and have mostly focused on the normal-weight concrete. However, only few studies that have considered the light weight concrete. Eight Beams were tested in this research under four point bending test. Two beams were taken as a control beams without any external bonding of Carbon Fiber Reinforced polymer. Another two …

Comparison Of Methane Production From Household Waste, Sunita Baniya

Civil Engineering Theses - Archive

Anaerobic digestion is a biochemical process in which various microorganisms transform complex organic compounds to methane, along with carbon dioxide, water vapor and a small amount of other trace gases in absence of oxygen. Methane from anaerobic digestion processes is being increasingly utilized as an alternative energy source in developing as well as developed countries. These days the energy crisis is very acute in rural communities of developing countries, where fuelwood has been and still is the major source of daily used fuel. Through anaerobic digestion, clean-burning fuel for cooking can be produced from degradation of household organic wastes, solving …

Impact Of Weather Factors On Go-Around Occurrence, Bharath Donavalli

Civil Engineering Theses - Archive

A “go-around” occurs when an aircraft, which is on final approach, aborts it landing due to unsatisfactory conditions. Go-arounds have a significant impact on the capacity of the airports and pose a serious concern at large airports, especially for airports with diagonal runways. Go-arounds occur due to manual errors, mechanical faults and weather factors. This study focuses on the impact of weather factors on go-around occurrence. The study includes wind gust, storm events (thunderstorm, rain and snow) and visibility as the weather factors under investigation. The author uses a factorial sampling strategy where these factors are segmented into additional categories …

Sustainable Reuse Of Fly Ash To Mitigate Landfill Methane, Sharon Priyadarshini

Civil Engineering Theses - Archive

According to US, EIA 2014 coal alone produces nearly 40% of electricity more than another source in US. Out of the 110 million tons of Coal combustion by-products (CCBs) generated per year as a result of coal combustion, 47% is reused whereas 53% is stored on-site or sent to landfills. There are a number of adverse economic and environmental impacts associated with storage and disposal of coal. Methane (CH4) is a powerful greenhouse gas (GHG), contributing 32% of current climate forcing (US EPA, 2015). Landfill gas comprises of 50-55% CH4 and 40-45% CO2. Global warming potential of CH4 is 28 …

Air Dispersion Modeling Of Multiple Natural Gas Well Pads At Different Terrain Conditions And Determination Of Inverse Distance Weighting Function Exponent, Fatemeh Khalaj

Civil Engineering Theses - Archive

Natural gas production and development has been widely spreading all over the United States. Texas has been leading the nation in natural gas production by holding approximately twenty three percent of the nation’s natural gas reserves. However, natural gas exploration, drilling, production and distribution process have impacts on air quality and human health. The emissions from natural gas processes could be categorized as volatile organic compounds (including Hazardous Air Pollutants), methane, carbon monoxide, nitrogen dioxides, particulate matter and some other minor emitted pollutants, which have the potential of causing serious health problems and also impact air quality from an environmental …

Safety Aspects Of Bicyclists In A Connected Vehicle Environment, Ajaykumar Patil

Civil Engineering Theses - Archive

The revival in the number of bicyclists, bike infrastructure investments and bike policies in the U.S. in the last two decades has escalated the importance of bicycling as a mode of transportation. With the proliferating role of the bicycle mode, bike fatalities continue to grow, too. In response to the increase in fatalities and crashes caused by human driven vehicles, the automobile industry and governments seek to develop autonomous vehicles that can address most of the human related crash causes. While increasing safety remains the primary goal of autonomous vehicles (AV) innovation, the difficulty of bicyclist and pedestrian detection using …

Improving Hydrologic Prediction For Large Urban Areas Through Stochastic Analysis Of Scale-Dependent Runoff Response, Advanced Sensing And High-Resolution Modeling, Amir Norouzi

Civil Engineering Dissertations - Archive

Due to urbanization and climate change, large urban areas such as the DallasFort Worth Metroplex (DFW) area is vulnerable not only to river flooding but also flash flooding. Due to the nonstationarities involved, projecting how the changes in land cover and climate may modify flood frequency in large urban areas is a challenge. Part I of this work develops a simple spatial stochastic model for rainfall-to-areal runoff in urban areas, evaluates climatological mean and variance of mean areal runoff (MAR) over a range of catchment scales, translates them into runoff frequency as a proxy for flood frequency, and assesses its …

Structural Retrofit Of Reinforced Concrete Circular Columns Using Cfrp, Ahmed Haider Mohiuddin

Civil Engineering Theses - Archive

Fiber reinforced polymer (FRP) composites have developed numerous applications in the field of Civil Engineering, mostly because of their beneficial properties like high strength-to=weight ratio and high corrosion resistance. This study presents an easy and expedient finite element (FE) able to accurately estimate the axial load carrying capacity of reinforced concrete (RC) circular columns confined with externally bonded carbon fiber reinforced polymer (CFRP) sheets. The element is able to model collapse due to concrete crushing. The FE generated in this study is used the load carrying capacity of CFRP confined RC columns subjected to concentric loading. Constitutive models for materials …

Sustainability Assessment Of Recycled Asphalt Mixtures In Texas, Reza Saeedzadeh

Civil Engineering Dissertations - Archive

The pavement practitioners use more recycled materials in asphalt mixtures in order to compensate for the high price of petroleum products and save the limited resources of virgin materials. Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) have been in wide use in asphalt mixtures for several decades. Public perception on the utilization of recycled materials is that the mixtures become more cost effective and more environmental friendly. This is true when the initial stage of construction of pavements is assessed. However, a mixture that costs less and/or burdens the environment less at the beginning may require more frequent …

Emerging Investigators Series: Virus Mitigation By Coagulation: Recent Discoveries And Future Directions, Joe Heffron, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Waterborne viruses are widespread and persistent in the environment. Coagulation is an effective process for mitigating viruses in drinking water. This review examines recent studies of virus mitigation by coagulation processes in the context of the latest scientific advances. Virus sorption is impacted by electrostatic forces, as well as the hydrophobic effect, steric hindrance, hydrodynamics and interactions with the water matrix. Organic matter in the water may hinder or enhance sorption, depending on virus structure and environmental factors. In addition to physical separation in flocs, coagulation processes have been shown to inactivate viruses. This review evaluates reports of virus inactivation …

Design And Resistance Factor Calibration Of Pipe Piles In California, Yujie Hu

Civil Engineering Theses - Archive

Steel pipe piles, either open ended or close ended, are widely used in the state of California as bridge foundations due to high load bearing capacity, light weight, and outstanding workability. The design methods currently used by Caltrans were developed based on limited field data and are lack of field validations of the recent development of steel pipe piles. In this thesis study, 45 high quality steel pipe pile load tests performed in various soil conditions were collected from Caltrans’ load test data to evaluate available design methods and calibrate the resistance factors of selected design methods. A total of …

Potential Application Of Ultra-High Performance Fiber-Reinforced Concrete With Wet-Mix Shotcrete System In Tunneling, Jean Gamarra

Civil Engineering Theses - Archive

In the tunneling industry, shotcrete has been used for several decades. The use of shotcrete or wet-mix spray-on methods allows the application of this method in complex underground profiles and shapes. The need for time efficient spraying methods and constructability for lining coverage opens the door for technologies like steel and synthetic fiber reinforced shotcrete to achieve a uniform and a good quality product. An important advantage of the application of fiber reinforced concrete in shotcrete systems for tunneling is that almost no steel fixing is required. This leads to several other advantages including safer working conditions during excavation, less …

Effects Of Vertical Ground Motion On Seismic Performance Of Reinforced Concrete Flat-Plate Buildings, Sara Jean George

UNLV Theses, Dissertations, Professional Papers, and Capstones

Reinforced concrete flat plate is a type of structural system widely used for office and residential buildings in many areas including those with high seismic risk. In the regions of high seismicity, moment frames or shear walls are employed to resist lateral loading while the flat-plate system is designed to primarily resist gravity loading. Flat-plate structures must maintain lateral deformation capacity as well as resist gravity loading under seismic loads. The deformation capacity of a slab-column connection is a function of vertical shear transferred from slab to column. The effects of vertical loading become even more exaggerated when the flat-plate …

Solar Energy Storage In Molten Salt Shell Structures, Nathan David Tyrrell Loyd

UNLV Theses, Dissertations, Professional Papers, and Capstones

Molten salts (MS) in the 580°C range could be used to store excess energy from solar power stations and possibly from nuclear or coal. The energy can be stored up to a week in large containers at elevated temperature to generate eight hours of electricity to be used at night or during peak demand hours. This helps to reduce the fluctuation experienced at thermal solar power stations due to weather conditions. Our research supported by Office of Naval Research (ONR), presents a survey of salts to be used in molten salt technology and the design of large steel and hybrid …

Laboratory Evaluation Of Geogrid-Reinforced Flexible Pavements, Mohammadreza Sharbaf

UNLV Theses, Dissertations, Professional Papers, and Capstones

An experimental laboratory program to assess the effectiveness of biaxial and triaxial geogrid-reinforced flexible pavements to reduce roadway section was carried out. Six laboratory tests were conducted using a steel cylindrical mold with dimensions of 1.8 m (6 ft) in diameter and 2.1 m (7 ft) in height. The studied reinforced and unreinforced (without geogrid) sections consisted of a locally-obtained subgrade with a minimum thickness of 1.5 m (5 ft) and an asphaltic surface course of 7.6 cm (3 in). The base thickness of three tests was 30.5 cm (12 in) while for the other three tests used base thickness …

Perchlorate Bioremediation: Controlling Media Loss In Ex-Situ Fluidized Bed Reactors And In-Situ Biological Reduction By Slow-Release Electron Donor, Sichu Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

The main concern of perchlorate exposure through drinking water is its effects on the production of thyroid hormone, which is important for human metabolism and child’s brain development. The US Environmental Protection Agency (EPA) has listed perchlorate in the contaminant list as well as in the Unregulated Contaminant Monitoring rule.

The extent of perchlorate contamination can be categorized by the level of contamination into parts per million (ppm) levels, typically in locations where perchlorate was manufactured, and parts per billion (ppb) levels where perchlorate was used for various purposes. Ion-exchange is generally adopted for treating ppb levels of perchlorate while …

Strengthening Of Lightweight Reinforced Concrete Beams Using Carbon Fiber Reinforced Polymers (Cfrp), Tariq Al Jaafreh

Civil Engineering Dissertations - Archive

This research aimed to investigate the effect of utilizing “Fiber Reinforced Polymer” (FRP) on the light weight concrete beams. The main hypothesis is that such utilization of the FRP will lead to strengthened lightweight beams. The research that has been done on this relationship is somewhat broad in the scope and have mostly focused on the normal-weight concrete. However, only few studies that have considered the light weight concrete. Eight Beams were tested in this research under four point bending test. Two beams were taken as a control beams without any external bonding of Carbon Fiber Reinforced polymer. Another two …

Comparison Of Construction Methods For Building An Underground Freight Transportation In Texas, Niloofar Rezaei

Civil Engineering Theses - Archive

Freight transportation by trucks constitutes approximately 80% of total freight transportation in Texas and it is expected to approximately double by the year 2040. Social and environmental costs are adverse impacts of moving freights by trucks. Underground Freight Transportation (UFT) significantly reduces these negative impacts and is more sustainable method of freight transportation. UFT includes close-fitting vehicles carrying freight through underground pipelines or tunnels between terminals. The main objective of this research is to compare two construction methods: (1) tunneling using tunnel boring machine (TBM) and (2) tunneling using open-cut. To conduct this research, a comprehensive literature search on various …