Civil and Environmental Engineering Commons^™

A Strategic Approach To Effectively Manage Supplier Quality Within The Construction Industry, Rufaidah Almaian

Graduate Theses and Dissertations

The aim of the research is to determine the best practices for supplier quality management (SQM) in the construction industry that ensure that the supplied materials and equipment for construction projects are within the quality requirements. The research is based on three main objectives. The first objective is to describe and assess the process of assuring supplier quality inside and outside the construction industry. The second objective is to develop a framework for the supplier quality process based on the collection of SQM practices from multiple data sources. The third objective is to assess the SQM practices within the developed …

Investigation Of Dairy Wastewater Using Biowish, Ada Mingwah Chan

Master's Theses

Various bacterial products from BiOWiSH^TM Technologies have been tested in dairy wastewater experiments to determine the bacterial mixes’ ability for enhanced degradation of biochemical oxygen demand (BOD), solids, and nitrate concentrations. The dairy wastewater was augmented with various bacterial composition obtained from BiOWiSH^TM. The bacterial mixes experimented were US Aqua, Thai Aqua, BMT, Osprey, Fruit Wash, KLB, LCM1, and MDG. Method development was a crucial process to optimize and test the effects of the BiOWiSH^TM Technologies bacterial mixes.

After 5 experiments, the BOD tests showed that for some of the tests, the redosage of bacteria helped …

Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson

Master's Theses

Packed-bed digesters are an alternative to covered lagoon digesters for methane production and anaerobic treatment of dilute wastewaters such as dairy barn flush water. The physical media of packed-beds retain biofilms, often allowing increased treatment rates. Previous studies have evaluated several types of media for digestion of dilute wastewaters, but cost and media fouling have setback commercial development. A major operational cost has been effluent recirculation pumping.

In the present effort, a novel approach to anaerobic digestion of flush dairy water was developed at pilot-scale: broken walnut shells were used as a low-cost packed-bed medium and effluent recirculation was replaced …

Field And Greenhouse Studies Of Phytoremediation With California Native Plants For Soil Contaminated With Petroleum Hydrocarbons, Pahs, Pcbs, Chlorinated Dioxins/Furans, And Heavy Metals, Matthew Robert Poltorak

Master's Theses

Native and naturalized California plant species were screened for their phytoremediation potential for the cleanup of soil contaminated with petroleum hydrocarbons (PHCs), poly-aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated dioxins/furans, and heavy metals. This screening was followed by controlled greenhouse experiments to further evaluate the phytoremediation potential of the best candidates. Field specimens and soils used for this study were collected from the former Energy Technology Engineering Center (ETEC) at the Santa Susana Field Laboratory in Southern California that was operated by the Department of Energy (DOE). Soils at this site contain all of the contaminants of interest (COIs). Nine …

The Relationship Between Bicycles And Traffic Safety For All Road Users, Jasmine A. Martin

Master's Theses

Over the past twenty years bicycle use as a mode of transportation has grown considerably in the United States. Other studies have examined the individual bicyclist’s risk in proportion to the growth in cycling across cities, a phenomenon referred to as ‘safety in numbers.’ This study expands from that research and examines the effect of cyclists on road safety for all road users.

The study examines the roles of bicycle modal split, a city wide analysis, and bicycle infrastructure, a site based analysis, in road safety outcomes. For the city based analysis, twenty years of crash data in 12 California …

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 …

Lateral-Torsional Buckling Capacity Of Tapered-Flange Moment Frame Shapes, Leah O'Neill

Theses and Dissertations

While moment frames are a popular lateral-force resisting system, their constant cross-section can lead to inefficiencies in energy absorption and stiffness. By tapering the flange width linearly toward the center of the beam length, the energy absorption efficiency can be increased, leading to a better elastic response from the beam and more elastic stiffness per pound of steel used. Lateral-torsional buckling is an important failure mode to be considered for tapered-flange moment frame shapes. No closed-form or finite element solutions have yet been developed for tapered-flange I-beams with a non-uniform, linear moment gradient and intermediate bracing conditions. In this study, …

Full-Scale Testing Of Blast-Induced Liquefaction Downdrag On Auger-Cast Piles In Sand, Joseph Erick Hollenbaugh

Theses and Dissertations

Deep foundations like auger-cast piles and drilled shafts frequently extend through liquefiable sand layers and bear on non-liquefiable layers at depth. When liquefaction occurs, the skin friction on the shaft decreases to zero, and then increases again as the pore water pressure dissipates and the layer begins to settle, or compact. As the effective stress increases and the liquefiable layer settles, along with the overlaying layers, negative skin from the soil acts on the shaft. To investigate the loss of skin friction and the development of negative skin friction, soil-induced load was measured in three instrumented, full-scale auger-cast piles after …

Gis-Based Route Risk Assessment Of Hazardous Material Transport, Myungwoo Lee

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The transportation of hazardous materials keeps increasing across the United States due to the growing consumption of goods and rising need for manufactured materials. Furthermore, concerns are mounting over the safe surface transportation of hazardous materials. Highways and rails are the most common modes of transport for hazardous materials, although the risk posed from highway transport of hazardous materials may be higher due to the fact that highways are public while rails are mostly private. The majority of hazardous material cargo is carried on the highway network by trucks. Due to possible adverse effects on human and animal populations in …

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 …

Lateral Resistance Of Piles Near Vertical Mse Abutment Walls, Cody Hatch

Theses and Dissertations

A full scale MSE wall was constructed and piles were driven at various distances behind the wall. Lateral load testing was conducted and the performance of the pile, wall, and reinforcement were measured. The piles were 12.75 inch pipe piles, and the wall was reinforced with welded wire grid reinforcement. The objective of the testing was to characterize the relationship between the lateral pile resistance and the distance of the pile behind the back face of the MSE wall. Load-displacement curves are presented for the piles located behind the wall at 66 inches (5.3 diameters), 55 inches (4.3 diameters), 41 …

Influence Of Pile Shape On Resistance To Lateral Loading, Guillermo Bustamante

Theses and Dissertations

The lateral resistance of pile foundations has typically been based on the resistance of circular pipe piles. In addition, most instrumented lateral load tests and cases history have involved circular piles. However, piles used in engineering practice may also be non-circular cross-section piles such as square and H piles. Some researchers have theorized that the lateral resistance of square piles will be higher than that of circular piles (Reese and Van Impe, 2001; Briaud et al, 1983; Smith, 1987) for various reasons, but there is not test data to support this claims. To provide basic comparative performance data, lateral load …

Developing A University-Wide Course On Sustainability: A Critical Evaluation Of Planning And Implementation, Can B. Aktas, Rosemary Whelan, Howard Stoffer, Edmund Todd, Cindy L. Kern Ph.D.

Civil Engineering Faculty Publications

Sustainability is an issue of increasing importance in today's world. Institutions of higher education are undergoing change towards incorporating sustainable development principles within their teaching, research, service, and community outreach efforts. This article presents a case study of the development and implementation of one such initiative: a university-wide freshman course centered on the topic of sustainability. The objective of the course was to expose freshman students to important sustainability issues in a common course team-taught by faculty from various disciplines. The article presents experiences and recommendations as a guide to administrators, faculty and researchers at other institutions of higher education …

Catechol Oxidation By Ozone And Hydroxyl Radicals At The Air-Water Interface, Elizabeth A. Pillar, Robert C. Camm, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic emissions of aromatic hydrocarbons promptly react with hydroxyl radicals undergoing oxidation to form phenols and polyphenols (e.g., catechol) typically identified in the complex mixture of humic-like substances (HULIS). Because further processing of polyphenols in secondary organic aerosols (SOA) can continue mediated by a mechanism of ozonolysis at interfaces, a better understanding about how these reactions proceed at the air–water interface is needed. This work shows how catechol, a molecular probe of the oxygenated aromatic hydrocarbons present in SOA, can contribute interfacial reactive species that enhance the production of HULIS under atmospheric conditions. Reactive semiquinone radicals are quickly produced upon …

Performance Evaluation And Integrated Management Of Airport Surface Operations, Qing Wang

USF Tampa Graduate Theses and Dissertations

The demand for aviation has been steadily growing over the past few decades and will keep increasing in the future. The anticipated growth of traffic demand will cause the current airspace system, one that is already burdened by heavy operations and inefficient usage, to become even more congested than its current state. Because busy airports in the United States (U.S.) are becoming "bottlenecks" of the National Airspace System (NAS), it is of great importance to discover the most efficient means of using existing facilities to improve airport operations.

This dissertation aims at designing an efficient airport surface operations management system …

Finite Element Modelling And Dilation Of Frp-Confined Concrete Columns, Osama Youssf, Mohamed Elgawady, Julie E. Mills, Xing Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Concrete dilation is one of the main parameters that controls the stress-strain behavior of confined concrete. Several analytical studies have been carried out to predict the stress-strain behavior of concrete encased in fiber-reinforced polymer (FRP), which is crucial for structural design. However, none of these studies have provided a simple formula to determine the dilation parameter that is always required in the finite element (FE) material modelling of concrete. This paper presents a simple empirical model predicting the confined concrete dilation parameter within the theoretical framework of a Karagozian and Case type concrete plasticity model. A set of 105 FRP-confined …

Hydroshare: Advancing Collaboration Through Hydrologic Data And Model Sharing, David G. Tarboton

Civil and Environmental Engineering Faculty Publications

HydroShare is an online, collaborative system being developed for open sharing of hydrologic data and models. The goal of HydroShare is to enable hydrology researchers to easily discover and access hydrologic data and models, retrieve them to their desktop for local analysis and perform analyses in a distributed computing environment that may include grid, cloud or high performance computing. Users may also share and publish outcomes (data, results or models) into HydroShare, using the system as a collaboration platform. HydroShare is expanding the data sharing capability of the CUAHSI Hydrologic Information System by broadening the classes of data accommodated. HydroShare …

United States Patent Application Publication, John H. Posselius, Christopher A. Foster, Santosh Pitla, Scott A. Shearer, Joe D. Luck, Michael P. Sama, Rodrigo S. Zandonadi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A multiple robot control architecture including a plurality of robotic agricultural machines including a first and second robotic agricultural machine. Each robotic agricultural machine including at least one controller configured to implement a plurality of finite state machines Within an individual robot control architecture (IRCA) and a global information module (GIM) communicatively coupled to the IRCA. The GIMs of the first and second robotic agricultural machines being configured to cooperate to cause said first robotic agricultural machine and said second agricultural machine to perform at least one agricultural task.

Improved Bayesian Multi-Modeling: Integration Of Copulas And Bayesian Model Averaging, Shahrbanou Madadgar, Hamid Moradkhani

Civil and Environmental Engineering Faculty Publications and Presentations

Bayesian Model Averaging (BMA) is a popular approach to combine hydrologic forecasts from individual models, and characterize the uncertainty induced by model structure. In the original form of BMA, the conditional probability density function (PDF) of each model is assumed to be a particular probability distribution (e.g. Gaussian, gamma, etc.). If the predictions of any hydrologic model do not follow certain distribution, a data transformation procedure is required prior to model averaging. Moreover, it is strongly recommended to apply BMA on unbiased forecasts, whereas it is sometimes difficult to effectively remove bias from the predictions of complex hydrologic models. To …

Development Of A Reusable Nutrient Recovery System To Sustainably Integrate Small-Scale Sanitation And Agriculture, Jorge Luis Calabria

USF Tampa Graduate Theses and Dissertations

Emerging technologies in sanitation and food production foster the potential to advance progress towards key sustainable development goals of ensuring adequate sanitation and food security to all. Non-Sewered Sanitation Systems (NSSSs), as detailed by the recent International Organization for Standardization’s (ISO) 30500 standard, are being developed to overcome challenges of lacking sanitation infrastructure and resource scarcity by providing autonomous, off-grid wastewater treatment (WWT) service in a much smaller footprints than large centralized treatment facilities. A promising NSSS platform is the anaerobic membrane bioreactor (AnMBR) that can achieve high (WWT) throughput in a small footprint using ultrafiltration (UF) membrane filtration to …

Calculation For Moment Capacity Of Beam-To-Upright Connections Of Steel Storage Pallet Racks, Tuo Wang, Xianzhong Zhao, Yiyi Chen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Steel storage pallet rack structures are three-dimensional framed structures, which are widely used to store different kinds of goods. For the easy accessibility to stored products, pallet racks are not usually braced in the down-aisle direction. The down-aisle stability is mostly provided by the characteristics of beam-to-upright connections, and the characteristics of upright base connections. In this paper, calculation for moment capacity of beam-to-upright connections is carried out. A mechanical model is presented firstly. Based on the model, moment capacity is related to the failure capacity, directly determined by the failure mode, of the topmost tab of the beam-end-connector and …

Design Method Of Bending Load-Carrying Capacity For Sandwich Panels With Different Metal Panel On Both Sides, Yanli Guo, Xingyou Yao, Kai Liu

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The sandwich panels, with plain and shallow grain pressed metal plate as the face sheets, and glass wools, rigid polyurethane foam, and rock wools as core materials, have excellent heat insulation and mechanical behavior, and been used as curtain walls for tall buildings in recent years in China. Since wind load and temperature action are the main actions for curtain walls, the sandwich panels are flexural members. In this paper, the design method and design formula of flexural load-carrying capacity and flexural deflection of a kind of sandwich plates with different metal panel on both sides are discussed and proposed. …

Study On The Flexural Capacity Of Cold-Formed Steel Joists-Osb Composite Floors, X. H. Zhou, Y. Shi, R. C. Wang, Y. J. Liu

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Two full scale specimens were tested to study the flexural capacity of cold-formed steel joists and OSB (Oriented strand board) composite floors. Test results indicated the composite floors had high bearing capacity and small deformation, and the screw spacing significantly affected the load-carrying capacity. The main failure modes were flexural and torsional buckling of floor joist, and the interactive buckling of compression flange, web and crimp. The wave length of bucking equalled to the adjacent screw spacing. Then the specimens were analyzed by commercial software ANSYS and the nonlinear FEM calculation results agreed well with the test results. Furthermore, detailed …

Finite Element Modeling Of New Composite Floors Having Cold-Formed Steel And Concrete Slab, Yazdan Majdi, Cheng-Tzu Thomas Hsu, Mehdi Zarei

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

In this research, the structural behavior of a new type of U.S. patented composite floor system is explored through finite element modeling. The new composite floor incorporates cold-formed (light-gauge) steel profiles as the joist on bottom, a corrugated steel deck as the formwork for concrete, a hat channel (furring channel) as the continuous shear connector and finally a concrete slab on top. All steel parts in the system are cold-formed and connected together by self-drilling fasteners. In this study, a comprehensive three-dimensional finite element modeling is performed for the composite floor system. A local bond-slip model is applied to simulate …