Civil and Environmental Engineering Commons^™

Innovative Gtfs Data Application For Transit Network Analysis Using A Graph-Oriented Method, Philippe Fortin, Catherine Morency, Martin Trépanier

Journal of Public Transportation

Public transit networks are constantly evolving in the face of frequent economic and social challenges. There exists a large knowledge base on travel demand; however, there is a shortage of information on travel supply and networks. To our knowledge, no analysis tool can, at this point, systematically characterize a network and observe changes over time in a structured and automated manner. This paper addresses this issue and proposes a graph-oriented method for developing an analysis tool that will characterize a single network and then provide the necessary means to compare two distinct networks. A time-expanded model was applied to import …

Applying Ahp And Clustering Approaches For Public Transportation Decisionmaking: A Case Study Of Isfahan City, Alireza Salavati, Hossein Haghshenas, Bahador Ghadirifaraz, Jamshid Laghaei, Ghodrat Eftekhari

Journal of Public Transportation

The main purpose of this paper is to define appropriate criteria for the systematic approach to evaluate and prioritize multiple candidate corridors for public transport investment simultaneously to serve travel demand, regarding supply of current public transportation system and road network conditions of Isfahan, Iran. To optimize resource allocation, policymakers need to identify proper corridors to implement a public transportation system. In fact, the main question is to adopt the best public transportation system for each main corridor of Isfahan. In this regard, 137 questionnaires were completed by experts, directors, and policymakers of Isfahan to identify goals and objectives in …

Assessing Park-And-Ride Efficiency And User Reactions To Parking Management Strategies, Krae E. Stieffenhofer, Michael Barton, Vikash Gayah V.

Journal of Public Transportation

Increasing the number of spaces at overutilized park-and-rides often is not possible due to budgetary and other constraints. Instead, transit agencies may instead seek to maximize the number of people that are able to use the existing spaces through various parking management strategies. Unfortunately, the efficiency of park-and-rides is difficult to measure, so agencies cannot accurately quantify existing use or improvement after parking management strategies have been applied. This study proposed and tested a method to measure the person-efficiency of park-and-ride lots through an onsite audit. Additionally, a user survey was proposed to confirm the audit results and unveil reactions …

Investigation Of Wheeled Mobility Device Orientation And Movement On Streetcars And Light Rail Vehicles During Normal And Emergency Braking, Andrea J. Mather, Katharine M. Hunter-Zaworski

Journal of Public Transportation

Wheeled mobility devices have been accessing public transit vehicles for decades, and most new rail transit systems are accessible. This has increased ridership by people with disabilities. Side-facing orientation on rail transit vehicles often is considered an option to increase capacity for wheeled mobility devices. This paper reports findings of a study of vehicle dynamics and wheeled mobility device orientation on rail transit vehicles. The study used acceleration data and field observations to evaluate wheeled mobility devices in longitudinal and side-facing orientations on streetcar and light rail vehicles. Results from the study include recommendations for longitudinal-oriented areas for wheeled mobility …

Lap Splice Development Length Of Rebar In Stabilized Hollow Interlocking Compressed Earth Blocks, Thomas S. Bowdey

Master's Theses

This thesis investigates the tensile performance of unconfined lap splices in specimens constructed from interlocking compressed earth block (ICEB) units. All lap splice specimens were constructed from hollow ICEB half units with one side grouting channel. ICEB units used in this research were exclusively produced from the Soeng Thai Model BP6 block press. The BP6 block press is currently manufactured in Thailand under the guidance and direction of the Center of Vocational Building Technologies (CVBT). All ICEB units and grout constructed for this research were created from mix proportions of soil, sand, cement, and water. Rebar bar sizes were restricted …

An Equivalent Plate Model With Orthotropic Material Properties For Adjacent Box-Beam Bridge Superstructure, Timothy Alexander Schnell

Masters Theses

Reflective cracking over the longitudinal joints of adjacent box-beam bridges is a welldocumented and recurrent problem; it is a concern because it leads to poor durability performance. These cracks develop during early stages of bridge construction and have not been eliminate by the design revisions implemented so far.

This study is aimed at developing a rational load demand analysis model for calculating the moment acting at the longitudinal joints in order to determine the impact of post-tensioning on mitigating reflective cracking.

The scope of the study includes calculating moment demand at the shear keys using a rational analysis model based …

Nondestructive Evaluation Of Steel Bridges: Methods And Applications, Theodore Hopwood Ii, Christopher Goff, Jared Fairchild, Sudhir Palle

Kentucky Transportation Center Research Report

Nondestructive evaluation (NDE) methods can be used to assess in-service steel bridges for problematic conditions caused by factors such as design, manufacturing, fabrication, and the service effects of traffic and corrosion. This report discusses typical NDE test methods used on bridges, including penetrant testing, magnetic particle testing, eddy current testing, ultrasonic testing (including phased array testing), radiography, and acoustic emission testing. NDE operations such as flaw location, characterization, and sizing are covered as well. Results of a national survey of departments of transportation’s (DOTs) use of NDE are presented. A simple procedure for using NDE to address DOT bridge concerns …

Condition Factor Calibration For Load And Resistance Factor Rating Of Steel Girder Bridges, Pranav M. Shakya

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

The Load and Resistance Factor Rating (LRFR) is a reliability-based rating procedure complementary to the Load and Resistance Factor Design (LRFD). The intent of LRFR is to provide consistent reliability for all bridges regardless of in-situ condition. The primary difference between design and rating is the uncertain severity and location of deterioration, including the potential future loss of strength for an element already evidencing deterioration. Ostensibly, these uncertainties are accounted for by applying an additional strength reduction factor: the condition factor, ϕ_c. Currently, condition factors are nominally correlated to the condition of the member, which can be Good, …

Multimedia Techniques For Construction Education And Training, Wayne A. Bunnell

Open Access Theses

The current profession of civil engineering often focuses education and training on code compliance rather than constructability and construction techniques. Also, it is well accepted that it takes a decade or more for engineers to develop a high-level project construction understanding and many state departments of transportation rely on in-field training for entry-level inspectors, with little or no education provisions for contractors. This research investigated the use of time-lapse photography to develop training and education material that will improve the understanding of project construction and crucial quality control specifications of an entry-level engineer, contractor, or inspector. Overall, the project team …

New Screening Method For Overweight Vehicles, Goran Veljko Milutinovic

Open Access Theses

Throughout the U.S., state agencies are issuing an increasingly large number of permits for overweight vehicles every year. There are various methods used by state agencies to process permit requests; the Indiana Department of Transportation employs a screening process that consists of the Tennessee Formula (allowable weight is determined and checked, for every axle group) in combination with the Gross Vehicle Weight limit. If a permit truck satisfies these two screening criteria, it is permitted; otherwise, it is further processed with refined analyses. The Tennessee Formula is based on Allowable Stress Design. However, most design and evaluation conducted today is …

Quantifying Asphalt Emulsion-Based Chip Seal Curing Times Using Electrical Resistance Measurements, Miguel A. Montoya Rodriguez

Open Access Theses

Chip seals are among the most cost-effective surface treatments available for asphalt pavement preventive maintenance. Chip sealing typically consists of covering a pavement surface with asphalt emulsion into which aggregate chips are embedded. The asphalt emulsion cures through the evaporation of water, which helps to provide mechanical strength for the chip seal. Ultimately, the curing process enables the emulsion to adhere to the pavement while keeping the aggregate chips in place. The curing time for the chip seal depends on many factors, such as the asphalt emulsion and aggregate types, aggregate moisture content, emulsion and aggregate application rates, and environmental …

Effect Of Temperature On Deep Lined Circular Tunnels In Isotropic And Transversely Anisotropic Elastic Ground, Fei Tao

Open Access Theses

A tunnel is a passageway constructed through soil or rock. It is one of the most important underground structures and has been widely used in transportation. Much research has been done on tunnel performance and on the interaction between ground, excavation, liner installation and support. The work has provided a better understanding of the interplay that exists between deformations and stresses transferred from the ground to the support. Significant insight into the problem has been provided by closed-form analytical solutions. A number of analytical formulations have been obtained for underground openings and lined tunnels under different scenarios, namely shallow or …

The Influence Of Alkalinity Of Portland Cement On The Absorption Characteristics Of Superabsorbent Polymers (Sap) For Use In Internally Cured Concrete, Juan D. Tabares Tamayo

Open Access Theses

The concrete industry increasingly emphasizes advances in novel materials that promote construction of more resilient infrastructure. Due to its potential to improve concrete durability, internal curing (IC) of concrete by means of superabsorbent polymers (SAP) has been identified as one of the most promising technologies of the 21st century. The addition of superabsorbent polymers into a cementitious system promotes further hydration of cement by providing internal moisture during the hardening and strength development periods, and thus limits self-desiccation, shrinkage, and cracking.

This thesis presents the work performed on the series of cement pastes with varying alkalinity of their pore solutions …

Fea Methodology For System-Level Redundancy Evaluation: Application To Non-Composite Steel Bridges, Francisco Javier Bonachera Martin

Open Access Dissertations

Currently, all steel bridges with members designated as Fracture Critical Members (FCMs) are required to undergo hands-on inspections every 24 months. A FCM is a primary steel tension member (or portion of) which failure results in collapse or loss of serviceability of a bridge. However, presently, there are no codified procedures used to evaluate system-level redundancy in steel bridges. In this dissertation, finite element analysis (FEA) procedures, techniques and inputs were researched in order to develop bridge models that account for the mechanisms that lead to redundant capacity after the failure of a primary steel member. These mechanisms include partial …

The Effects Of Chloride-Based Deicing Chemicals On Degradation Of Portland Cement Mortars With Alkali Reactive Aggregate, Charles Yicheng Chiu

Open Access Dissertations

The assessment of the influence of deicing chemicals on alkali reactivity of aggregates is still an area of active research, particularly with respect to the combined effects of long-term exposure to deicers, freezing and thawing cycles, and wetting and drying cycles. In order to develop a more comprehensive view of these topics, the present study was conducted in three phases. The focus of the first phase was on studying the effects of the chloride-based deicers on the alkali silica reaction (ASR) using accelerated test methods (i.e. the test was performed at high temperature (80 °C) as per modified ASTM C1260). …

Bridge Maintenance To Enhance Corrosion Resistance And Performance Of Steel Girder Bridges, Luis M. Moran Yanez

Open Access Dissertations

The integrity and efficiency of any national highway system relies on the condition of the various components. Bridges are fundamental elements of a highway system, representing an important investment and a strategic link that facilitates the transport of persons and goods. The cost to rehabilitate or replace a highway bridge represents an important expenditure to the owner, who needs to evaluate the correct time to assume that cost. Among the several factors that affect the condition of steel highway bridges, corrosion is identified as the main problem. In the USA corrosion is the primary cause of structurally deficient steel bridges. …

Fracture Analysis In Biomimetic Bouligand Architectures, Nobphadon Suksanqpanya

Open Access Dissertations

The Bouligand structure, which is found in many biological materials, is a hierarchical architecture that features uniaxial fiber layers assembled periodically into a helicoidal pattern. Many studies have highlighted the high damage-resistant performance of Bouligand structures and its biomimetic materials. One of the outstanding species with the Bouligand structures is the smashing Mantis Shrimp, Odontodactylus Scyllarus, (or stomatopod) due to its capability of generating high speed, high acceleration blows using its raptorial appendage to defeat highly armored preys. The load-bearing part of this appendage, the dactyl club, contains an interior region, which is mainly characterized by the Bouligand structure. This …

Geometric Accuracy Evaluation Of Mobile Terrestrial Lidar Surveys With Supporting Algorithms, Chisaphat Supunyachotsakul

Open Access Dissertations

Mobile Mapping System (MMS) technology is widely used for many applications, hence quantifying its accuracy is a very important and essential task and is a primary focus of this research. In general, to perfrom geometric accuracy evaluation of MMS data, validation points/features are needed. A method is needed to capture a point feature off the roadway in a position where a target on the ground surface would not be visible to the scanner. In this study, eight sphere targets with 14" diameter were placed on the shoulder of the roadway over validation points on the ground. The sphere targets were …

Policy Design Tool For Managing Indoor Residential Water Demand In Water-Scarce Regions, Mujahed M. Thneibat

Open Access Dissertations

In view of population growth; climate change; and economic evolution, water resources in numerous parts of the world have reached their natural capacities. Consequently, the ability of many countries to grow; meet the basic needs of inhabitants; and protect the environment will be endangered like never before unless water resources are smartly handled and managed. ^ In the past few decades, many developed and developing countries have suffered from water scarcity, and more are certain to follow. The water security dilemma is much more challenging in developing countries. Water utilities have had to follow regulatory plans to manage demand on …

Identifying And Prioritizing Critical Success Factors For Fixed Base Operators In The United States: A Mixed Method Approach, Yu Wang

Open Access Dissertations

Fixed Base Operators (FBOs) are major service providers for the general aviation (GA) sector, which closely connect the public with the aviation industry. However, over the past decade, the U.S. GA industry has experienced a decline in the numbers of registered aircraft, pilots, and airports. Due to the fact that FBOs significantly contribute to the aviation industry, further research studies regarding the FBO-sector at a national level are needed. The purpose of this dissertation was to identify and prioritize the critical success factors (CSFs) that promote the success of FBO operations in the United States.

The methodology consisted of a …

Computer Vision-Based Structural Assessment Exploiting Large Volumes Of Images, Chul Min Yeum

Open Access Dissertations

Visual assessment is a process to understand the state of a structure based on evaluations originating from visual information. Recent advances in computer vision to explore new sensors, sensing platforms and high-performance computing have shed light on the potential for vision-based visual assessment in civil engineering structures. The use of low-cost, high-resolution visual sensors in conjunction with mobile and aerial platforms can overcome spatial and temporal limitations typically associated with other forms of sensing in civil structures. Also, GPU-accelerated and parallel computing offer unprecedented speed and performance, accelerating processing the collected visual data. However, despite the enormous endeavor in past …

Overseas Chinese Environmental Engineers And Scientists Association (Oceesa) Report, Dec 2016., Yung-Tse Hung, Wen-Chi Ku, Lawrence K. Wang

Civil and Environmental Engineering Faculty Publications

This Overseas Chinese Environmental Engineers and Scientists Association (OCEESA) report is 2016 Directory of Overseas Chinese Environmental Engineers and Scientists Association (OCEESA), Report number: OCEESA/JL-2016/33D1, December 2016, ISSN 1072 -7248. This report was prepared by Yung-Tse Hung, Permanent Executive Director, OCEESA. This report includes OCEESA contact information, list of OCEESA Directors, list of OCEESA past presidents, OCEESA membership data, constitutions and by laws of OCEESA (5 November 2000 edition), constitutions and by laws of OCEESA (14 February 2006 edition), constitutions and by laws of OCEESA (27 October 2013 edition), membership application form, letter from Wen-Chi Ku to confirm Yung-Tse Hung …

Continuous Long-Term Health Monitoring Using Ultrasonic Wave Propagation, Ece Erdogmus

Nebraska Department of Transportation: Research Reports

No abstract provided.

Improved Methodology For Developing Non-Motorized Safety Perfomance Functions, Keneth Morgan Kwayu

Masters Theses

This study aimed at improving the methodology for developing statewide non-motorized safety performance functions (SPFs). Due to lack of pedestrian and bicyclist counts, the methodology proposed a procedure for developing statewide surrogate non-motorized exposure measures using data that are available at statewide level. Eleven years non-motorized crashes at signalized urban intersections joining Arterial and Collector roads in Michigan were used to test the procedure.

The study also explored the use of Bayesian approach for modeling non-motorized crashes as an alternative to traditional classical count data models. Classical count data models that were considered as potential fit to the data include; …

Triclosan: An Instructive Tale, Patrick J. Mcnamara, Stuart B. Levy

Civil and Environmental Engineering Faculty Research and Publications

The Food and Drug Administration (FDA) recently released a final rule to ban triclosan and 18 other antimicrobial chemicals from soaps. We applaud this rule specifically because of the associated risks that triclosan poses to the spread of antibiotic resistance throughout the environment. This persistent chemical constantly stresses bacteria to adapt, and behavior that promotes antibiotic resistance needs to be stopped immediately when the benefits are null.

Experimental Evaluation Of Structural Steel Coating Systems, Elias Anis Toubia, Sadra Emami

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Departments of transportation (DOTs) currently use the conventional three-coat system as the predominant choice for the corrosion protection of steel bridge structures. Eliminating one step in the coating process could potentially save time and cost associated with lane closures and traffic control costs. This research paper evaluates several two-coat systems based on the zinc-rich primer and polysiloxane topcoat technology. All samples were conditioned and coated in a state-of-the-art, climate-controlled paint booth, simulating common field ENvironmental CONditions (ENCON) (ENCON 1: 25 °C/50% RH, ENCON 2: 10 °C/40%RH, and ENCON 3: 32°C/80% RH). Accelerated weathering tests were performed on 435 coated samples …

Sulfate Resistance Of Nanosilica Contained Portland Cement Mortars, Iani Batilov Batilov

UNLV Theses, Dissertations, Professional Papers, and Capstones

Soils, sea water and ground water high in sulfates are commonly encountered hostile environments that can attack the structure of concrete via chemical and physical mechanisms which can lead to costly repairs or replacement. Sulfate attack is a slow acting deteriorative phenomenon that can result in cracking, spalling, expansion, increased permeability, paste-to-aggregate bond loss, paste softening, strength loss, and ultimately, progressive failure of concrete. In the presented research study, Portland cement (PC) mortars containing 1.5% to 6.0% nanosilica (nS) cement replacement by weight were tested for sulfate resistance through full submersion in sodium sulfate to simulate external sulfate attack. Mortars …

Causes And Impacts Of Geotechnical Problems On Bridge And Road Construction Projects, Krishna Prasad Neupane

UNLV Theses, Dissertations, Professional Papers, and Capstones

Changes during the construction phase generate cost growth, schedule delays, and claims in any project. However, the impact of geotechnical problems on construction costs, schedules, and claims in bridge and road projects had not been investigated in depth. The major objectives of this study were to determine the geotechnical-related causes of cost and schedule growth and claims as well as their impacts on the bridge and pavement projects’ performance. This study also identifies mitigation measures to avoid cost and schedule growth and claims in these projects.

A survey was conducted with 53 engineers from state Department of Transportations (DOTs) and …

Occurrence And Proliferation Of Antibiotics And Antibiotic Resistance In Wastewater Treatment Plants, Majid Neyestani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Solids retention time (SRT) is one of the most important factors in designing and operating activated sludge systems for biological wastewater treatment. Longer SRTs have been shown to alter the structure and function of microbial communities, thereby leading to improved treatment efficacy with respect to bulk and trace organics, nutrient removal, and membrane fouling. However, research has also shown that longer SRTs lead to increased prevalence of antibiotic resistant bacteria, perhaps due to increased exposure to antibiotics present in influent wastewater. The purpose of this study was to characterize changes in microbial community structure in a laboratory-scale activated sludge system …

Evaluation Of Electron Donors For Perchlorate And Nitrate Biodegradation In Contaminated Groundwater Applications, Mayra Alejandra Sarria Cortes

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the United States, perchlorate contamination has been widely reported, including in Las Vegas, Nevada, where perchlorate has been detected at concentrations of 34.7 mg/kg in vadose zone soil and 0.18-3.7 g/L in groundwater. Once this groundwater reaches the Las Vegas Wash, there is potential for widespread contamination of drinking water sources throughout the Southwest, including in Nevada, Arizona, and California. This issue is becoming increasingly important because even at low perchlorate concentrations, sensitive populations such as infants and pregnant women can be potentially impacted due to perchlorate’s ability to hinder iodine uptake into the thyroid glands, which leads to …