Civil and Environmental Engineering Commons^™

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 …

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 …

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 …

2016 Maintenance Customer Survey, R. Clark Graves, David L. Allen

Kentucky Transportation Center Research Report

The Kentucky Transportation Center, with the assistance of the University of Kentucky’s Survey Research Center, administered a telephone survey to 1,221 licensed drivers throughout the state to gauge their opinion of the Kentucky Transportation Cabinet’s (KYTC) maintenance activities. Survey respondents were distributed throughout KYTC’s 12 highway districts. The survey focused on five areas of highway maintenance: roadside features, pavement surfaces, shoulders, drainage and signs/markings. Respondents indicated they were most satisfied with the current maintenance of signs, guardrail, and striping. Pavement surfaces and potholes, and shoulders and roadway drainage, received the lowest rankings — given that the driving public is very …

Recycling Ceramic Waste Powder And Its Usage As An Alternative Ingredient In Concrete, Dima Mamoun Kanaan

Theses

Green environment is a challenging concern to accomplish in today’s world. This could be accomplished through an effective and beneficial recycling system through reusing solid waste materials. The study and exploration of alternative ingredients for concrete-making industry started more than five decades ago. Concrete that contains solid waste is referred to as “Green” concrete. Ceramic tiles are widely used in most structures; its production creates waste powder. Using ceramic waste powder (CWP) as an ingredient to partially replace cement in concrete will have a positive and progressive environmental impact in addition will help reserve natural resources. In this study, CWP …

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 …

Performance Assessment Of Deteriorated And Retrofitted Steel Hp Piles, Steven T. Stauffer

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

Deterioration of aging bridges can be attributed to an assortment of mechanisms throughout the structure, with remediation policies also varying. This study focused on assessing the validity of the Nebraska Department of Roads’ (NDOR) reinforced concrete encasement retrofit for corroded steel HP piles. Experiments were designed and conducted to test the capacity of the NDOR retrofit and evaluate failure limit states. Two pile locations were considered: abutment and pile bent. For each location there was a non-deteriorated, deteriorated, and retrofitted case. These cases represented the pile at key stages during its life. NDOR’s concrete encasement retrofit provided the required stability …

Shear Behavior Of High-Strength Self-Consolidating Concrete In Nebraska University Bridge Girders, Alex Griffin, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Current reinforced and prestressed concrete design equations were developed for conventional concrete elements. Self-consolidating concrete (SCC) typically contains a lower coarse aggregate content and size than conventional concrete, which potentially hinders the aggregate interlock contribution to a concrete's shear strength. Thus, shear design equations must be verified with SCC mixtures. Two full-scale precast, prestressed concrete Nebraska University girders were tested to assess the shear behavior of high-strength SCC. Both girders were designed to permit two tests on each girder, both with and without shear reinforcement. Ultimate shear loads and crack patterns were documented and compared with code estimates, finite element …

The Influence Of Superabsorbent Polymer (Cassava Startch) On The Rheological Behavior Of Cement Pastes., James Wong

Electronic Theses and Dissertations

Rheological properties are the properties typically reference flow properties of concrete and are related to processing, construction, and setting. The purpose of this research was to investigate the influence of superabsorbent polymers (SAP) and superplasticizer (SP) on rheological properties, specifically of cement pastes with 0.35, 0.45 and 0.55 water-to-cement ratios (w/c), SAP water replacement dosages of 0%, 5%, 10%, 15%, 20% and 25% were tested. Tests included rheological measurements of yield stress, viscosity using the Bingham equation and the flow behavior index using Herschel-Bulkley equation. Slump diameter tests were used to measure flow of the cement pastes. Comparisons of slump …

Acoustic Firearm Discharge Detection And Classification In An Enclosed Environment, Lorenzo Luzi, Eric Gonzalez, Paul Bruillard, Matthew Prowant, James Skorpik, Michael Hughes, Scott Child, Duane Kist, John E. Mccarthy

Mathematics Faculty Research

Two different signal processing algorithms are described for detection and classification of acoustic signals generated by firearm discharges in small enclosed spaces. The first is based on the logarithm of the signal energy. The second is a joint entropy. The current study indicates that a system using both signal energy and joint entropy would be able to both detect weapon discharges and classify weapon type, in small spaces, with high statistical certainty.

Bs News May/June

Building Services Engineering

No abstract provided.

Evaluation Of Unbound Pavement Layers Moduli Using The Miniaturized Pressuremeter Test, Alaa Mohammed Shaban

Theses and Dissertations

A small version of pressuremeter known as Miniaturized Pressuremeter (MPMT) was designed and built to provide high quality pavement parameters. The device, which is a modified version of PENCEL Pressuremeter (PPMT) has a 6 inch inflatable probe capable of quickly and reliably measuring the stress-strain response of thin pavement layers. The MPMT stress-strain data can be used as inputs to evaluate existing pavement structures as a part of a pavement management system, and as critical inputs in empirical pavement design methods. To check in-situ operational performance of the new probe, twenty four MPMT and PPMT tests were performed in parallel …

Laboratory Modeling Of Piping Initiation Behavior Through Constricted Outlet, Ibrahim Ahmed Abdelmotelb Ibrahim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Backward erosion piping is a type of internal erosion. It occurs beneath water structures as a result of seepage force. It needs two conditions to take place; 1) sufficient hydraulic head to drive the seepage force, and 2) cohesive layer overlies the sand layer and this will lead to concentration of flow. Many researches were done in the past in an attempt to predict the critical gradient. But it was just taking into account the buoyant unit weight which found in recent research that piping can occur at much lower values than was predicted. And other researches were too conservative …

Chromium Oxidation By Disinfectants And Oxidants Used In Drinking Water Treatment, Nathan D. Rogers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This project investigated the behavior of hexavalent chromium (Cr(VI), a potential carcinogen) in drinking water. While Cr(VI) can exist naturally, it can also be oxidized from Cr(III), a known trace nutrient. Recently, the State of California implemented a water regulation specifically for Cr(VI) at 10 parts per billion (ppb). This project completed a comprehensive evaluation of chromium behavior when in contact with common drinking water treatment chemicals including chlorine, monochloramine, chlorine dioxide, potassium permanganate, and ozone.

The results of these oxidation experiments are highly applicable to water treatment facilities. If a treatment plant is using monochloramine, there is no indication …

Optimizing Sustainable Integrated Use Of Groundwater, Surface Water And Reclaimed Water For The Competing Demands Of Agricultural Net Return And Urban Population, Silvia Anastasia Landa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The world population is growing rapidly. In developing countries, the growing population is mostly in urban areas. A bigger population requires more food, and more food requires more water. The water needed for food and people comes from the same sources: surface water (rivers, lakes, etc.) and groundwater (aquifers). Thus, there is a competing water demand between people and agriculture in urban areas.

In this research, we use computer software to make a model of the hydrologic system that focuses on surface water and groundwater. To make the model, we use data from real aquifers and streams in order to …

The Effects Of Upstream Straight Pipe Length On Magnetic Flow Meter Accuracy, Bradley C. Clawson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In closed conduit water systems, being able to accurately measure flow is absolutely essential. For many meter designs, including electromagnetic induction meters (also known as magnetic flow meters), the greatest accuracy is achieved when the device is calibrated correctly. Optimal meter accuracy often depends on the flow conditions associated with the upstream geometry in the pipe system. Manufacturers typically give standards for the length of straight pipe required upstream of the meter. These standards vary, however, and do not address every possible configuration that may be installed upstream of the straight pipe requirement.

An investigation on the effects of the …

Physically Based Modeling Of The Impacts Of Climate Change On Streamflow Regime, Nazmus Shams Sazib

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding the implications of climate change on streamflow regime is complex as changes in climate vary over space and time. However, a better understanding of the impact of climate change is required for identifying how stream ecosystems vulnerable to these changes, and ultimately to guide the development of robust strategies for reducing risk in the face of changing climatic conditions. Here I used physically based hydrologic modeling to improve understanding of how climate change may impact streamflow regimes and advance some of the cyberinfrastructure and GIS methodologies that support physically based hydrologic modeling by: (1) using a physically based model …

Rhizosphere Interactions Between Copper Oxide Nanoparticles And Wheat Root Exudates In A Sand Matrix; Influences On Bioavailability And Uptake, Paul Mcmanus

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Copper oxide nanoparticles (CuO NPs) are extremely small particles (less than 1 nm in one or more dimension, or one billionth (10^-9) of a meter) used in a diverse range of industries. They have been shown to travel through water systems, and like pharmaceuticals, can end up in wastewater treatment plants and then be land applied as biosolids, where crops are grown for animal consumption, potentially leading to food chain accumulation.

Cu is an essential micronutrient for plants, but is phytotoxic at higher concentrations. CuO NPs present an increasingly real environmental threat to agriculture in soils treated with …

A Comprehensive Safety Analysis Of Diverging Diamond Interchanges, Holly Lloyd

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

With the implementation of new roadway configurations, there is a great need to study the influence of the roadway design on the crash rate. Utah is one of the leading states in the implementation of the Diverging Diamond Interchange.

In order to determine the effects of the new roadway configuration on the safety of the intersection, this study employs an Empirical Bayes before-after study of the crash rates at selected Diverging Diamond Interchanges in Utah. The results of the Empirical Bayes method were also used to calculate crash modification factors. The total number of crashes at each site were analyzed. …

Live-Load Test And Finite-Element Model Analysis Of A Steel Girder Bridge, Jake L. Morrill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Utah Transportation Center in conjunction with the Mountain Plains Consortium sponsored a study to investigate the performance, and condition of a steel, twin, I-girder bridge. The bridge is located on the Idaho-Oregon border near Payette, Idaho, and was designed to carry traffic over the Snake River.

Bridge Diagnostics Inc. was contracted by the Idaho Transportation Department to perform a live-load test on the bridge. This testing included the placement of 62 gauges that measured the response of the bridge as heavy trucks were driven across it.

A 3-D finite-element model of the bridge was generated and compared to the …

The Effects Of Meter Orientation Downstream Of A Short Radius Elbow On Electromagnetic Flow Meters, Jared C. Justensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Electromagnetic flowmeters (known as magnetic flow meters) are a widely used type of flowmeter. The accuracy of magnetic flow meters are a function of several factors, not the least of which is the flow condition inside the pipe. It has been shown that disturbances in the velocity profile affects the accuracy of a magnetic flow meter (Luntta, 1998). Accordingly, manufacturers of magnetic flow meters give installation guidelines. These guidelines help prevent the user from installing the meter in a pipe configuration that is likely to cause the meter to produce inaccurate results. Although most manufacturers provide recommendations about the amount …

Application Of Computational Fluid Dynamics In Flow Measurement And Meter Design, Zachary B. Sharp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Flow measurement has been an important part of society for hundreds of years. For this reason there are many methods to measure flow rates both in open channel scenarios like irrigation canals and also in closed conduits like pipelines that supply water for human use. This research focused on Venturi flow meters which have been used to measure flow since the 1890’s. The object of this research was to use computational fluid dynamics and laboratory data to provide industry with applicable answers to some under researched areas in flow measurement. The areas chosen for this research include areas requested by …

The Application Of Unmanned Aerial Vehicle To Precision Agriculture: Chlorophyll, Nitrogen, And Evapotranspiration Estimation, Manal Elarab

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Precision agriculture (PA) is an integration of a set of technologies aiming to improve productivity and profitability while sustaining the quality of the surrounding environment. It is a process that vastly relies on high-resolution information to enable greater precision in the management of inputs to production. This dissertation explores the usage of multispectral high resolution aerial imagery acquired by an unmanned aerial systems (UAS) platform to estimate three fundamental crop parameters (plant chlorophyll, leaf nitrogen and crop water demand). The UAS acquired imagery in the visual, near infrared and thermal infrared spectra with a resolution of less than a meter …

Anaerobic Digestion Process Stability And The Extension Of The Adm1 For Municipal Sludge Co-Digested With Bakery Waste, Morris Elya Demitry

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The anaerobic digestion process is used to treat and convert waste organic matter to biogas (principally methane and carbon dioxide) through biological, chemical and physical reactions. The biogas can be used as a source of energy recovery. In order to increase the biogas production rate, two different kinds of waste (municipal wastewater treatment sludge and bakery waste) were mixed together to enhance the anaerobic process and increase the biogas production in pilot scale reactors. The process succeeded in increasing biogas production and at the same time kept the process of treatment effective when high rates of organics were fed to …

Live Load Testing And Analysis Of A 48-Year-Old Double Tee Girder Bridge, Victor J. Torres

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A 48-year-old prestressed double tee girder bridge located on Icy Springs road in Coalville, Utah, was tested for live load. The test measured strains, deflections and rotations. The instruments used for measuring the respective measurements were strain gages, deflectometers ("twangers") and tiltmeters.

From the recorded measurements a finite element model (FEM) was calibrated to validate the modeling techniques based on the test data. The FEM implemented two joint link elements to connect the flanges of the FEM deck to model the transverse load distribution of the bridge deteriorated shear connectors. The abutment restraints were modeled by one joint link elements. …

Achieving Uniform Flow Distribution In Compact Irrigation Splitter Boxes With High Flow Rates, Joshua Ryan Hogge

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In many irrigation systems and networks, there are multiple water users and shareholders who take their water from different locations along a single canal or pipeline. Often, irrigation splitter boxes are used to divert water to multiple shareholders from a single location. The splitter boxes, which can be small and compact, are generally installed at different locations along a piped irrigation supply line. The purpose of a splitter box is to split a specific amount of water so that each user receives their allotted portion, regardless of the flow rate in the system.

Each splitter box usually includes two compartments, …

Accumulation And Release Of Trace Inorganic Contaminants From Biofilm Matrices Produced And Challenged Under Drinking Water Distribution System Conditions, William W. Kent

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Drinking water distribution systems (DWDS) are used to transport drinking water from the place of treatment to your home. DWDS are made of many types of pipe materials and have the potential to accumulate materials such as iron and manganese oxides and biofilms that serve as reservoirs for toxic trace inorganic contaminants (TICs) such as thallium, arsenic, and lead. These materials can be stable, but changes in water quality or a physical disturbance such as road construction or water use changes may result in a TIC release, causing water quality degradation. This study used glass columns filled with glass beads …

Evapotranspiration Estimation: A Study Of Methods In The Western United States, Clayton S. Lewis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Theoretical water use of well-watered vegetation in the western United States was investigated by comparing a gridded dataset developed from satellite and ground instruments to weather stations representative of irrigated agricultural conditions. Since wetter environments are cooler and therefore subject to lower levels of evaporation than the same scenario with warmer temperatures, models derived from dryland and often populated areas overestimate potential plant needs in semi-arid or arid conditions. Evaluation of the model revealed an acceptable fit for air temperatures and solar radiation but with less confidence in humidity and wind speeds. Ultimately, the last two parameters were minor components …

Traffic Sign Management: Data Integration And Analysis Methods For Mobile Lidar And Digital Photolog Big Data, Majid Khalilikhah

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Traffic signs often convey critical information to drivers. However, traffic signs are only effective when clearly visible and legible. This study aims to determine the effects of various damage and deterioration forms on sign retroreflectivity, identify the most important factors affecting traffic sign visual condition, predict traffic sign vandalism that obstructs critical messages to drivers, and identify important environmental factors contributing to the temporary obstruction of the sign messages. To do so, two data sets are used. A sample data of over 1,700 signs was manually collected in the field, and the background retroreflectivity of each sign was measured using …

Continued Development Of A Non-Proprietary, High-Tension, Cable End Terminal System, Jennifer D. Schmidt, Robert W. Bielenberg, John D. Reid, Ronald K. Faller

Nebraska Department of Transportation: Research Reports

A non-proprietary, cable guardrail system is currently under development for the Midwest States Pooled Fund Program. A cable guardrail end terminal was necessary to accompany the cable guardrail system. The objective of this research project was to develop design recommendations for the cable end terminal. Bogie testing that was previously completed on a design concept indicated delayed cable release, which was an undesired performance that led to vehicle instabilities. Several design changes were recommended for better end terminal performance and to reflect the changes made to the cable median barrier. An LS-DYNA model of the modified cable end terminal was …