Civil Engineering Commons^™

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 …

Causes Of Change Orders And Its Impact On Road Maintenance Contracts, Kabindra Kumar Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Change orders (CO) commonly generate cost-growth, schedule-growth or both, in construction as well as in maintenance contracts. Literature reviews revealed that the causes and impact of CO on new construction contracts had been comprehensively studied, but the causes and impact of CO in maintenance contracts remained neglected. This study collected CO data on road maintenance contracts to determine the amount of CO and the most frequent and high-risk road maintenance activities that had CO. A Delphi study was conducted with 33 maintenance engineers from the state Department of Transportation (DOT) to identify causes of CO and its impact on cost …

Safety Analysis Of Freeway Segments With Unobserved Heterogeneity And Second Order Spatial Effects, Eneliko Mujuni Mulokozi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Safety analysis of freeway networks entails the quantification of crash frequency influencing factors which include roadway and traffic characteristics, environmental factors as well as human factors. This quantification can be used to detect locations with large impacts on the occurrence of crashes which in turn assist engineers and planners to improve safety levels of the network. Roadway characteristics are comprised of the physical elements of the road geometry such as section length, median and right shoulders, speed-exchange lanes, the number of main facility as well as geometry of the entrance from and exit to the main freeway facility. Traffic characteristics …

A Multi-~Procedural Approach To Evaluating Walkability And Pedestrian Safety, Peris Nyagah

UNLV Theses, Dissertations, Professional Papers, and Capstones

Walking has sound health benefits and tends to be a pleasurable experience requiring no fuel, fare, license, nor registration. Whilst walking is recommended as part of physical activity, it is necessary to provide a conducive and safe walking environment. In an effort to determine an optimum combination of infrastructure that would create walkable, transit-oriented neighborhoods eliminating unnecessary motorized trips; various approaches evaluating an assortment of features in the walking environment have been implemented. However, some factors such as crash risk which have an essential contribution to the suitability of the walking environment have yet to be considered. Therefore the objective …

Alkali-~Activated Fly Ash Binders: Feasibility As A Sustainable Alternative To Ordinary Portland Cement For Pre-~Cast Systems, Kimberly Sierra

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fresh, load-dependent, transport, and durability properties of alkali-activated fly ash mortars were studied. The influences of activator concentration, solution-to-binder ratio, curing condition, activator type, and sodium silicate-to-total solution ratio on the properties of the studied alkali-activated mortars were examined. This study was divided in two phases. The first phase dealt with the use of sodium hydroxide as the sole activator. The second phase of the study was divided into two parts, both of which used a combination of sodium hydroxide and sodium silicate as the activator solution. Part I of phase II used elevated temperature curing conditions, whereas part II …

Fluoride And Phosphate Removal From Industrial And Domestic Wastewaters Using Cerium Chloride, John Michael Gonzales

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of cerium chloride (CeCl3) to remove fluoride and phosphate from waters is addressed in this study. High concentrations of fluoride exist in groundwater especially in developing countries. Consumption drinking water containing high levels of fluoride can lead to serious cases of dental and skeletal fluorosis. Current defluoridation technologies are limited, especially for high levels of fluoride, and are expensive. Industrial wastewaters contribute to the highest fluoride contamination in the world. With the increasing production of electronic materials, the global fluoride concentration and fluoride-contaminated waters have grown tremendously. Excessive discharge of phosphate into the environment promotes eutrophication of lakes …

Development Of A Decision Support Framework For The Planning Of Sustainable Transportation Systems, Pankaj Maheshwari

UNLV Theses, Dissertations, Professional Papers, and Capstones

With the rapid increase in economic development throughout the world, there is stress on the resources used to support global economy, including petroleum, coal, silver, and water. Currently, the world is consuming energy at an unprecedented rate never seen before. The finite nature of such non-renewable natural resources as petroleum and coal puts pressure on the environmental system, and ultimately reduces the availability of resources for future generations. Hence, it is critical to develop planning and operational strategies that seek to achieve a sustainable use of existing natural resources.

With this motivation, this dissertation focuses to develop a decision support …

Geotechnical Surrogates For Sediment Shear Behavior In Southern Nevada, Rinu Ann Samuel

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Nevada Department of Transportation design standards for deep foundations, particularly drilled shafts, in the Las Vegas Valley (LVV) may be overly conservative due to the challenges in characterizing strong but difficult-to-sample sediment strata, such as dense gravel, heavily cemented sediments, and mixed materials, which occur commonly in the LVV. Consequently, there is a need for investigating methods to assess the shear behavior of sediments that occur in the LVV in situ in working ranges of stress/strain, with the end goal of improving abilities to predict the capacity of drilled shafts in the LVV. To this end, global correlations of …

Effect Of Void Geometry On Strength, Stiffness, And Failure Modes Of Rock-Like Materials, Omed Yousif

UNLV Theses, Dissertations, Professional Papers, and Capstones

The host rock of portion of the first proposed high-level nuclear waste repository in the United States of America (Yucca Mountain, Nevada) is tuff rock that contains voids (lithophysae) with different shapes, sizes, and distributions. The existence of these voids can cause a dramatic change in the rock's mechanical properties such as uniaxial compressive strength, UCS, and Young's modulus, E. Accordingly, in an experimental program, the effects of void existence on the engineering properties of the tuff rocks was explored in a work of US Department of Energy conducted in the Department of Civil and Environmental Engineering and Construction of …

Bulbous Pier: Alternative To Bridge Pier Extensions, Amilcar Chavez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bridge deck splashing causes deterioration to the bridge structure and renders the bridge unsafe for motorist and pedestrians. The traditional countermeasure for bridge deck splashing is pier extension, the pier extension moves the pier wave away from the bridge deck, but retrofitting existing bridges with pier extensions is costly. This research proposes the bulbous pier concept as an alternative to pier extension.

The decrease in the pier wave produced by the bulb is due to energy subtracted by the bulb via two forces, the viscous resistance, and the wave-making resistance. The proposed mathematical model for the bulbous pier design follows …

The Use Of Cod, Toc, Fluorescence, And Absorbance Spectroscopy To Estimate Biochemical Oxygen Demand In Wastewater, Evelyn Aramaine Christian

UNLV Theses, Dissertations, Professional Papers, and Capstones

All wastewater treatment facilities must obtain a National Pollution Discharge Elimination System (NPDES) permit, which regulates the quality of water that is discharged. Common to all NPDES permits is a limit on organic matter, as determined by the five-day biochemical oxygen demand (BOD5) test. More rapid methods, such as chemical oxygen demand (COD), total organic carbon (TOC), fluorescence, and absorbance spectroscopy are also capable of quantifying organic matter. Previous studies indicate it is possible to develop correlations between these parameters. This study explored the correlations using influent, primary clarifier effluent, and finished effluent samples from an operational wastewater treatment plant …

Prediction Of Shear Strength And Ductility Of Cyclically Loaded Reinforced Concrete Columns Using Artificial Intelligence, Nicholas Gordon

UNLV Theses, Dissertations, Professional Papers, and Capstones

The shear strength and deformation capacities of reinforced concrete (RC) columns are governed by a multitude of variables related to material properties of the steel and concrete used in the design and construction of the columns. Predicting performance of RC columns using design variables is a complex, non-linear problem. The prediction of shear strength and ductility for these types of structural members has historically been performed using empirically or semi-empirically derived formulae based on experimental results. The introduction of cyclical lateral loading, such as the forces imposed on a structure during an earthquake, can result in severe degradation of shear …

Properties Of Concrete Containing Ggbf Slag And Nano-Silica, Mohammad Sajjadul Islam

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ground granulated blast furnace slag (GGBFS), a by-product from steel production, has been used as a partial replacement of portland cement in concrete for over a century. It constitutes a beneficial reuse of a by-product material, less consumption of portland cement concrete. Lower consumption of portland cement concrete can help reduce construction cost. Furthermore, it lowers the industrial carbon footprint, and landfill disposal which is a major environmental issue the world is facing today. The chemical composition of GGBF slag is similar to portland cement with hydraulic properties and additional pozzolanic properties with excellent alkali silica reactivity mitigation and resistance …

Identification Of Long Term Changes And Evaluation Of The Relationships Among Streamflow Variability And Oceanic-Atmospheric Indices, Soumya Sagarika

UNLV Theses, Dissertations, Professional Papers, and Capstones

To examine the effects of climate variability on streamflow, this thesis presents a comprehensive analysis of the streamflow variability of the continental United States and its association with oceanic-atmospheric indices. First, the presence of trends with consideration of short term and long term persistence followed by shifts over the past years in the continental U.S. streamflow were analyzed by using the non-parametric tests: Mann Kendall and Pettitt. Second, the spatio-temporal relationships between seasonal streamflow variability of continental U.S. and sea surface temperatures (SST) and 500 mbar geopotential height (Z500) of the Pacific and Atlantic were established using the singular valued …

High Strength Steel Fiber Reinforced Flow-Able Or Scc Concrete With Variable Fiber By Volume Fractions For Thin Plate And Shell Structures, Abebe Berhe

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to incorporate discrete, short, mechanically deformed, small diameter steel fibers into high strength concrete with f'c > 70 MPa (10 ksi) in an attempt to reduce and partially eliminate the need for steel rebar in concrete construction. By introducing steel fibers to high strength concrete mixture, the overall tensile, compressive and shear strength of the mixture can be improved immensely thus, replacing portions or major parts of the longitudinal, temperature and shrinkage reinforcements. The reduction or elimination of longitudinal and transverse reinforcements in the construction of structural or non-structural members can result in savings in …

Evaluation Of Phb Mid-Street Crossing System In Las Vegas, Nevada - Pedestrian Perspectives, Anna Eapen

UNLV Theses, Dissertations, Professional Papers, and Capstones

As the U.S. population ages and as more people choose to walk, it is critical to improve pedestrian safety. One of the best ways to encourage both pedestrians and vehicle drivers to behave safer is to make use of the most effective engineering traffic control systems. One such new technology is the Pedestrian Hybrid Beacon System (PHB), formerly known as the High-intensity Activated crosswalk (HAWK), a pedestrian-activated traffic-warning device. It features immediate activation of traffic warning lights from a dark state, a pedestrian countdown timer, and shorter pedestrian crossing times and traffic stoppage times compared to a traditional midblock traffic …

Gis Framework For Spatiotemporal Mapping Of Urban Flooding And Analyze Watershed Hydrological Response To Land Cover Change, Sayed Joinal Hossain Abedin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Urban flooding is a manmade disaster, and a recurrent problem in cities around the globe. Increased surface imperviousness due to urbanization along with inadequate drainage infrastructure system are the chief culprits for urban flooding. Flooding in an urban area brings about severe economic, structural, and environmental damages, and can be associated with casualties too. In order to evade flooding, an efficient flood model is imperative to study current flooding, and analyze flooding behavior to urban surface characteristics.

This research aims to develop a framework using Geographic Information System (GIS) to perform modeling and mapping of flood spatiotemporal variation in urban …

Effect Of Caliche On The Behavior Of Drilled Shafts, Rouzbeh Afsharhasani

UNLV Theses, Dissertations, Professional Papers, and Capstones

The current design methodology for a drilled shaft foundation in cohesionless soil is primarily based on ultimate skin friction values of drilled shafts. In order to obtain these values for each soil type, load tests such as Osterberg test are designed and performed. The Osterberg test layout is designed to estimate the capacity of drilled shaft by applying an upward load during the test and then calculating the downward capacity assuming the upward and downward capacity are the same. This method is appropriate for soils not containing caliche layers because caliche layers bond to the shaft and prevent skin friction …

Investigation Of Chloride Induced Corrosion Of Bridge Pier And Life-Cycle Repair Cost Analysis Using Fiber Reinforced Polymer Composites, Dinesh Dhakal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bridges are the long term investment of the highway agencies. To maintain the required service level throughout the life of a bridge, a series of maintenance, repair, and rehabilitation (MR&R) works can be performed. To investigate the corrosion deterioration and maintenance and repair practices in the bridge pier columns constructed in chloride-laden environment, a questionnaire survey was conducted within the 50 state Departments of Transportation (DOTs). Based on the survey data, two corrosion deterioration phases were identified. They were corrosion crack initiation phase and corrosion propagation phase. The data showed that the mean corrosion crack initiation phase for bridge pier …

Modeling Pavement Distress Rates Within U.S. Air Force Airfields, Lauren Sahagun

UNLV Theses, Dissertations, Professional Papers, and Capstones

Through the review of Pavement Condition Index (PCI) surveys completed at Air Force installations scattered across the continental United States, pavement engineers at the Air Force Civil Engineer Center propose that the predominant factor contributing to pavement distress development is climate. They suggest that within each pavement distress type (i.e. alligator cracking, rutting, spalling, etc.) a geographic pattern exists that is strongly correlated to the conventional climate zones within the US. Knowledge of these geographic patterns would equip pavement engineers and asset managers with a powerful tool to develop purposeful maintenance strategies specific to each distress type.

The following approach …

Exact Controllability Of The Lazer-Mckenna Suspension Bridge Equation, Lanxuan Yu

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is well known that suspension bridges may display certain oscillations under external aerodynamic forces. Since the collapse of the Tacoma Narrows suspension bridge in 1940, suspension bridge models have been studied by many researchers. Based upon the fundamental nonlinearity in suspension bridges that the stays connecting the supporting cables and the roadbed resist expansion, but do not resist compression, new models describing oscillations in suspension bridges have been developed by Lazer and McKenna [Lazer and McKenna (1990)]. Except for a paper by Leiva [Leiva (2005)], there have been very few work on controls of the Lazer-McKenna suspension bridge models …

Evaluation Of Earthquake Hazard For Las Vegas Valley, Nevada Incorporating Probabilistic Hazard Assessment And Non--Linear Site Response, Suchan Lamichhane

UNLV Theses, Dissertations, Professional Papers, and Capstones

Abstract from Manuscript 1, "An alternative analysis of the probabilistic seismic hazard for Las Vegas Valley, Nevada": Probabilistic seismic hazard calculations relevant for rock-site conditions in the Las Vegas Valley, Nevada (LVV) have been computed that account for seismic sources that are not included in the current (2008) USGS national seismic hazard model (NSHM) because of insufficient knowledge or documentation, using the commercial software package EZ-FRISK. The LVV is underlain by a system of mapped, active normal faults that comprise the Las Vegas Valley Fault System (LVVFS), with maximum potential earthquakes to M6.8. The 2008 NSHM explicitly includes only one …

Transport Properties Of Nano-Silica Contained Self-Consolidating Concrete, Borhan Moradi

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this research study, transport properties of various self-consolidating concretes (SCCs) containing nano-particles (SiO2) were investigated. Nano-silica replaced a portion of the cementitious materials at different replacement levels ranging from 1.5 to 7.5% by weight. For the purpose of this investigation, flow, bulk, and transport properties of SCCs were studied. The investigated transport properties were absorption, water penetration, rapid chloride permeability, capillary absorption, rapid migration, and chloride diffusion. Transport properties of nano-silica SCCs were also compared to those of equivalent silica fume (micro silica) contained concretes, as well as those of control mixture (concrete without nano or micro silica).

Test …

Plastic Deformation Of Steel Plates Under High Velocity Impact, Shawoon Kumar Roy

College of Engineering: Graduate Celebration Programs

• Measure material deformation under high velocity impact.
• Explore the capabilities of the newly developed Multiplexed Photonic Doppler Velocimetry (MPDV) system.
• Study factors that affect the accuracy of computational techniques to simulate high velocity impact.

Development Of A Visualization System For Highway Safety Management Using Safety Analyst, Indira Khanal

UNLV Theses, Dissertations, Professional Papers, and Capstones

The AASHTOWare software, Safety Analyst, is a state-of-the-art tool with significant capabilities and advanced analytical methods for comprehensive analysis and management of highway safety. However, currently, this tool provides very limited visualization capabilities. To address this limitation, this study proposes a Visualization System for Safety Analyst that provides graphical displays, including location and color-coded information for each module. In addition, the system generates charts, which have various degrees of resolution and aggregation; tables; and a report summarizing safety performance measures. The system can use Google Maps and/or ESRI ArcGIS to generate the graphical displays. The advantage of using Google Maps …

Simultaneous Equation Modeling For Crash Rate Of Freeway Segments, Anthony Ramos

UNLV Theses, Dissertations, Professional Papers, and Capstones

In 2010, the total number of reported traffic crashes in the state of Nevada was 51,664 of which 235 (0.6%) resulted in one or more deaths (Nevada Department of Transportation, 2012). The state's "Zero Fatalities" traffic safety campaign aims to reduce the rate even further. Out of the total number of crashes, Clark County (includes Las Vegas) accounted for 78.89%. This study examines safety improvement by developing advanced crash prediction models. The system of crash prediction equations consider geometric conditions and traffic volume using simultaneous equation modeling (SEM). The models are based on geometric characteristics and traffic volume data collected …

Influence Of Limestone Powder Content And Size On Transport Properties Of Self-Consolidating Concrete, Rebecca Kendal Spitek

UNLV Theses, Dissertations, Professional Papers, and Capstones

Self-consolidating concrete (SCC) requires higher cementitious materials content than conventional vibratory-placed concrete. This requirement leads to higher time-dependent properties (i.e., shrinkage (drying and autogeneous) and creep), increases formwork pressure, and results in a higher production cost. One alternative to alleviate excess creep and shrinkage, and to reduce cost, is to replace a portion of cementitious materials with mineral additives. The objective of this study was to examine the role of limestone powder, as a partial replacement of cementitious materials, on transport properties of self-consolidating concrete (SCC). A total of 10 different SCCs, including a control concrete, was prepared and test …

Investigating The Physical Properties And Runoff Treatment Capability Of Pervious Concrete Containing Granular Activated Carbon, Mark Elias Elkouz

UNLV Theses, Dissertations, Professional Papers, and Capstones

A current environmental concern is that of urban stormwater runoff, which can carry a multitude of contaminants and could threaten or impair surface waters. Pervious concrete (PC) is a type of concrete with significant void spaces that can facilitate infiltration and lead to less runoff. The EPA cites previous research to show that pervious pavement structures reduce such contaminants as metals and total suspended solids. Since Granular Activated Carbon (GAC) is a well-known contaminant adsorbent, the purpose of this research was to determine if PC with added GAC would result in improved runoff treatment, while still maintaining its material properties. …

Highway Routine Maintenance Cost Estimation For Nevada, Monika Hagood

UNLV Theses, Dissertations, Professional Papers, and Capstones

State highway agencies are obligated to maintain existing roads for the highway systems to work efficiently and with greater longevity. Every year NDOT is responsible for approximately 13,150 lane miles of existing infrastructure. With that in mind, resources need to be provided to maintain the highway system.

The purpose of this research was to estimate annual routine maintenance cost for several typical treatment methods of highways. Five prioritization categories of highways used by NDOT were considered. Linear regression models were developed that present the relationship between costs including total maintenance cost and five maintenance cost components: labor, equipment, materials, manpower …

Modeling Of Short Term And Long Term Impacts Of Freeway Traffic Incidents Using Historical Data, Vidhya Kumaresan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Traffic incidents are major contributors to non-recurring traffic congestion in most urban areas in United States. In addition to losses in terms of injury and property damage, freeway incidents also produce negative effects on the system including increased travel delays, fuel consumption and vehicle emissions. Incident management strategies are aimed at reducing the impacts caused by such incidents. Development of guidelines or models to quantify the impacts of these incidents on the society can aid in analyzing the effectiveness and economic feasibility of such incident management strategies.

The first objective of this study is to calibrate models that relate the …