Civil Engineering Commons^™

The Energy Efficiency And Living Comfort Of A Stabilized Rammed Earth Dwelling In Comparison With A Traditional Stud Frame Building, David C. Johnson Iii

Graduate Theses, Dissertations, and Problem Reports (ETD)

During the last several decades, rammed earth construction has received renewed attention due to its many desirable characteristics. For construction, use, and end of life treatment, rammed earth construction has shown in research to reduce the embodied energy of residential building construction by 66-85% compared to building methods that use fired brick and concrete members. Research thus far also indicates that rammed earth construction may indeed be more energy efficient since the building material has a very high thermal inertia, henceforth, the rammed earth walls absorb thermal energy from the sun and release it into the building to reduce the …

Review Of Modern Nondestructive Testing Techniques For Civil Infrastructure, Shabnam Khanal

Graduate Theses, Dissertations, and Problem Reports (ETD)

The repair and maintenance of aging infrastructures, in the United States alone, are estimated to have backlogs of trillions of dollars. This has posed widespread concerns about the existing and proposed infrastructures to adequately sustain the quality of life in the near future. Efficient and cost-effective approaches, such as nondestructive testing (NDT), are therefore required to better shape our future. Various NDT techniques have been developed over the past two decades with cutting-edge advances towards investigation and condition assessment of civil infrastructures. While the performance of NDT techniques has reached unparalleled heights, limitations remain. On one side, are the instrument …

Climatic And Topologic Controls On The Complexity Of River Networks, Sevil Ranjbar Moshfeghi

Electronic Theses and Dissertations, 2020-2023

The emergence and evolution of channel networks are controlled by the competition between the hillslopes and fluvial processes on the landscape. Investigating the geomorphic and topologic properties of these networks is important for developing predictive models describing the network dynamics under changing environment as well as for quantifying the roles of processes in creating distinct patterns of channel networks. In this dissertation, the response of landscapes to changing climatic forcing via numerical-modeling and field observations was investigated. A new framework was proposed to evaluate the complexity of catchments using two different representations of channel networks. The structural complexity was studied …

Safety Evaluation Of Innovative Intersection Designs: Diverging Diamond Interchanges And Displaced Left-Turn Intersections, Ahmed Abdelrahman

Electronic Theses and Dissertations, 2020-2023

Diverging diamond interchanges (DDIs) and Displaced left-turn intersections (DLTs) are designed to enhance the operational performance of conventional intersections that are congested due to heavy left-turn traffic volumes. Since drivers are not familiar with these types of intersections, there is a need to evaluate their safety performance to validate their effect, and to estimate reliable and representative Crash Modification Factors (CMFs). The safety evaluation was conducted based on three common safety assessment methods, which are before-and-after study with comparison group, Empirical Bayes before-and-after method, and cross-sectional analysis. Furthermore, since DLTs showed poor safety performance, the study also investigated the operational …

Bond Behavior Of Advanced Fiber Reinforced Composite-Concrete Joints, Xingxing Zou

Doctoral Dissertations

“Externally bonding advanced composite materials to concrete structures is an effective way to improve their strength, ductility, and durability. The interfacial bond behavior is fundamental to understand the overall structural performance of concrete structures strengthened with advanced composite materials. This study includes a comprehensive investigation of the bond behavior of composite-concrete joints with different fiber reinforced composite types. First, a direct approach to determine the bond-slip relationship for fiber reinforced cementitious matrix (FRCM)-concrete joints based on fiber strain measurements was proposed. Then, an analytical solution to predict the full-range response of FRCM-concrete joints was derived by assuming a trilinear bond-slip …

Smartphone Sensor-Based Pedestrian Activity Recognition For P2v Communication And Warning System, Dhrubo Hasan Chowdhury

Electronic Theses and Dissertations, 2020-2023

The ubiquity of smartphones has made a remarkable influence on everyone's day to day life. Variety of useful built-in sensors provide smartphones with a convenient floor for data collection and analysis. Application development based on the user's location and movement is not a difficult task nowadays. But injuries and deaths due to smartphone-distracted movement on roadways is on the increase. This study explores the capabilities of smartphone inertial sensors for pedestrian activity recognition. Smartphone distracted movements can be predicted from the associated pedestrian's posture, thus inertial sensors can provide effective solution for this specific task. Volunteers were asked to perform …

Traffic Speed Prediction And Mobility Behavior Analysis Using On-Demand Ride-Hailing Service Data, Jiechao Zhang

Electronic Theses and Dissertations, 2020-2023

Providing accurate traffic speed prediction is essential for the success of Intelligent Transportation Systems (ITS) deployments. Accurate traffic speed prediction allows traffic managers take proper countermeasures when emergent changes happen in the transportation network. In this thesis, we present a computationally less expensive machine learning approach XGBoost to predict the future travel speed of a selected sub-network in Beijing's transportation network. We perform different experiments for predicting speed in the network from future 1 min to 20 min. We compare the XGBoost approach against other well-known machine learning and statistical models such as linear regression and decision tree, gradient boosting …

Prediction Of Pedestrians' Red Light Violations Using Deep Learning, Shile Zhang

Electronic Theses and Dissertations, 2020-2023

Pedestrians are regarded as Vulnerable Road Users (VRUs). Each year, thousands of pedestrians' deaths are caused by traffic crashes, which take up 16% of the total road fatalities and injuries in the U.S. (FHWA, 2018). Crashes can happen if there are interactions between VRUs and motorized transportation. And pedestrians' unexpected crossings, such as red-light violations at the signalized intersections, would expose them to motorized transportation and cause potential collisions. This thesis is intended to predict the pedestrians' red-light violation behaviors at the signalized crosswalks based on an LSTM (Long Short-term Memory) neural network. With video data collected from real traffic …

The Impacts Of Wave Energy Conversion On Coastal Morphodynamics In A Changing Climate, Cigdem Ozkan

Electronic Theses and Dissertations, 2020-2023

Fossil fuels, i.e., petroleum, natural gas, and coal, are the primary sources of global energy. Studies on the impacts of fossil fuels on climate change have shown the immediate need to reduce greenhouse gas emissions and adopt sustainable alternatives since these emissions result in warmer atmospheric temperatures, ocean acidification, glacier melting, sea level rise, and many other ramifications. In recent years, these alarming results have prompted governments worldwide to develop adaptation strategies for climate change, leading to increased investments in renewable energy resources. Globally, solar energy, wind energy, and hydropower have been the leading sources of renewable energy. Ocean wave …

Holistic Resilience Quantification Framework Of Rural Communities, Amanda Melendez

Theses and Dissertations--Civil Engineering

Communities need to prepare for anticipated hazards, adapt to varying conditions, and resist and recover rapidly from disturbances. Protecting the built environment from natural and man-made hazards and understanding the impact of these hazards helps allocate resources efficiently. Recently, an indicator-based and time-dependent approach was developed for defining and measuring the functionality and disaster resilience continuously at the community level. This computational method uses seven dimensions that find qualitative characteristics and transforms them into quantitative measures. The proposed framework is used to study the resilience of rural communities’ subject to severe flooding events. Harlan County in the Appalachian region is …

Effect Of Socioeconomic And Demographic Factors Of Driver Residence On Crash Occurrence, Shraddha Sagar

Theses and Dissertations--Civil Engineering

In the U.S., road traffic crashes are a leading cause of death. Crash data from the state of Kentucky shows that the per capita crash rates and crash-related fatalities were higher than the national average for over a decade. In effort to explain why the U.S. Southeast experiences higher crash rates than other regions of the country, previous research has argued the region’s unique socioeconomic provide a compelling explanation. Taking this observation as a starting point, this study examines the relationship between highway safety and socioeconomic characteristics using an extensive crash dataset from Kentucky.

The primary goal of this research …

Modeling Of Incident Type And Incident Duration Using Data From Multiple Years, Sudipta Dey Tirtha

Electronic Theses and Dissertations, 2020-2023

We develop a model system that recognizes the distinct traffic incident duration profiles based on incident type. Specifically, a copula-based joint framework with a scaled multinomial logit model (SMNL) system for incident type and a grouped generalized ordered logit (GGOL) model system for incident duration to accommodate for the impact of observed and unobserved effects on incident type and incident duration. The model system is estimated using traffic incident data from 2012 through 2017 for the Greater Orlando region, employing a comprehensive set of exogenous variables – incident characteristics, roadway characteristics, traffic condition, weather condition, built environment and socio-demographic characteristics. …

Effects Of Cellulose Nano-Fiber As An Additive On Performance Of Asphalt Binders And Mixes, Marco Paulo Pereira Castro

Electronic Theses and Dissertations

Findings of a study conducted on asphalt binders and mixes modified by addition of cellulose nanofiber (CNF) to evaluate the feasibility of them as an additive is presented in the current thesis. Cellulose Acetate (CA) is an ester of cellulose and is obtained by the reaction of cellulose with acetic anhydride and acetic acid in the presence of sulfuric acid. Due to its high temperature sensitivity, high ductility, large surface area, high strain resistance, and low electrical resistivity, cellulose acetate can be used for several application. The question is if CNF can be used as an additive in the asphalt, …

Mobility-As-A-Service: Assessing Performance And Sustainability Effects Of An Integrated Multi-Modal Simulated Transportation Network, Mohamed El-Agroudy

Electronic Theses and Dissertations, 2020-2023

Advances in information technology services have seen profound impacts on the state of transport services in the urban traffic environment. Mobility-as-a-Service (MaaS) represents the digital consolidation of users, operators, and public-private managing entities to provide totally comprehensive, integrated trip-making services. Users now enjoy extra flexibility for trip-making with new modal alternatives such as micro-mobility (e.g Lime Bikes, Spin Scooters) and rideshare (e.g. Lyft, Uber). However, current knowledge on the performance and interactive effects of these newer alternative modes is vague if not inconsistent. As such, these effects were studied through micro-simulation analysis of a multi-modal urban corridor in Orlando, Florida. …

Evaluation Of Safety And Mobility Benefits Of Connected And Automated Vehicles By Considering V2x Technologies, Md Hasibur Rahman

Electronic Theses and Dissertations, 2020-2023

The recent development in communication technologies facilitates the deployment of connected and automated vehicles (CAV) which are expected to change the future transportation system. CAV technologies enable vehicles to communicate with other vehicles through vehicle-to-vehicle (V2V) communications and the infrastructure through Vehicle-to-infrastructure (V2I) communications. Since the real-world CAV data is not currently available as of today, simulation is the most commonly used platform to evaluate the future V2X system. Although several studies evaluated the effectiveness of CAVs in a small roadway network, there is a lack of studies analyzing the impact of CAVs at the network level by considering both …

A Deep Learning Approach For Real-Time Crash Risk Prediction At Urban Arterials, Pei Li

Electronic Theses and Dissertations, 2020-2023

Real-time crash risk prediction aims to predict the crash probabilities within a short time period, it is expected to play a crucial role in the advanced traffic management system. However, most of the existing studies only focused on freeways rather than urban arterials because of the complicated traffic environment of the arterials. This thesis proposes a long short-term memory convolutional neural network (LSTM-CNN) to predict the real-time crash risk at arterials. The advantage of this model is it can benefit from both LSTM and CNN. Specifically, LSTM captures the long-term dependency of the data while CNN extracts the time-invariant features. …

Structural Performance Evaluation Of Dynamic Message Signs With Adhesive And Welded Joints, Ibin Amatya

Electronic Theses and Dissertations

The ultimate objective of this study was to determine the structural performance of the Dynamic Message Sign (DMS) bonded with chemical adhesive in terms of ultimate strength and fatigue strength. To achieve this objective, this study first investigated the effects of various parameters, including humidity and temperature on tensile, shear, peel, and cleavage strength through small-scale tests of adhesive specimens with variation in specimen width. The tensile, shear, peel, and cleavage specimens were conditioned in a temperature-humidity controlled chamber prior to its testing. The tensile, shear, peel, and cleavage specimens with different widths were tested according to American Society for …

Corrigendum To “Heavy Metal Ion Detection On A Microspot Electrode Using An Optical Electrochemical Probe” [Electrochem. Commun. 86 (2018) 94–98], Santanu Roy, Abhijeet Prasad, Rahul Tevatia, Ravi Saraf

Mid-America Transportation Center: Final Reports and Technical Briefs

The authors regret to inform an error. Ravi F. Saraf of this pub- lication discloses financial interest in Vajra Instrument as its founder and President. In accordance with its Conflict of Interest policy, the University of Nebraska-Lincoln’s Conflict of Interest in Research Committee has determined that this must be disclosed. The authors would like to apologise for any inconvenience caused.

Structural And Environmental Impact Of New-Generation Wide-Base Tires In New Brunswick, Canada, Izak M. Said, Jaime Hernandez, Seunggu Kang, Imad L. Al-Qadi

Civil and Environmental Engineering Faculty Research and Publications

The loading and environmental impacts of new-generation wide-base tires (NG-WBT) and dual tire assemblies (DTA) on typical asphalt concrete (AC) pavement sections of New Brunswick, Canada were evaluated using finite element method (FEM) analysis and life-cycle assessment. The impact of steering wheel was not considered in this study. The analysis considered realistic material models and loading conditions (i.e. AC viscoelastic characteristics and measured three-dimensional nonuniform tire–pavement contact loads). Predicted critical pavement responses were used in transfer functions to determine potential pavement damage. The NG-WBT loading resulted in greater critical pavement responses compared to that of DTA, especially near the surface …

Liana Abundance And Diversity Increase With Rainfall Seasonality Along A Precipitation Gradient In Panama, Anthony J. Parolari, Kassandra Paul, Aaron H. Griffing, Richard Condit, Ronaldo Perez, Salomón Aguilar, Stefan A. Schnitzer

Civil and Environmental Engineering Faculty Research and Publications

In tropical regions, rainfall gradients often explain the abundance and distribution of plant species. For example, many tree and liana species adapted to seasonal drought are more abundant and diverse in seasonally-dry forests, characterized by long periods of seasonal water deficit. Mean annual precipitation (MAP) is commonly used to explain plant distributions across climate gradients. However, the relationship between MAP and plant distribution is often weak, raising the question of whether other seasonal precipitation patterns better explain plant distributions in seasonally-dry forests. In this study, we examine the relationship between liana abundance and multiple metrics of seasonal and annual rainfall …

Econometric Frameworks For Multivariate Models: Application To Crash Frequency Analysis, Tanmoy Bhowmik

Electronic Theses and Dissertations, 2020-2023

Econometric crash frequency models are a major analytical tool employed for examining the critical factors influencing crash occurrence. However, there are several methodological challenges associated with existing models suggesting a continual need to develop advanced econometric framework to address these gaps. The current dissertation contributes towards addressing the methodological challenges in crash frequency analysis for analyzing multiple crash frequency variables for the same study unit by proposing advanced econometric approaches. The first part of the dissertation contributes to safety literature by conducting a comparison exercise between the two major streams of multivariate approaches - (1) simulation-based approach and (2) analytical …

The Relationship Between Roadway Homogeneity And Network Coverage For Network Screening, Riana Tanzen

Theses and Dissertations--Civil Engineering

In the context of transportation safety engineering, network screening is a method of identifying and prioritizing high-risk locations for potential safety investment. Since its release, the Highway Safety Manual (HSM) has facilitated the adoption of Safety Performance Functions (SPF) to predict the number of crashes for the network screening of any facility type. The predictive model becomes more reliable when developed from crash data with homogeneous roadway segments and this homogeneity can be attained by applying specific geometric attributes to the dataset. The caveat to this method is the requirement of adjustment factors (AFs) to adjust the predicted estimate for …

Fluvial Sediment Organic Matter Degradation Identified With Elemental And Isotopic Fate During Laboratory Incubation, Brenden Riddle

Theses and Dissertations--Civil Engineering

Fluvial sediment is well recognized as a critical factor in both carbon and nutrient budgets within stream systems. However, we find very few studies of reactivity and isotope enrichment for stream water from agricultural and urban streams and the class of substrate known as fluvial sediment organic matter. This study investigated the hypothesis that fluvial sediment is subject to degradation even though many previous studies have considered this class of substrate generally inert. Therefore we qualify that elemental and isotopic signatures of fluvial sediment organic matter should be considered potentially non-conservative when used in tracer studies. Methods applied to this …

Adaptive Tracking Controller For Real-Time Hybrid Simulation, Alejandro Palacio-Betancur

Theses and Dissertations--Civil Engineering

Real-time hybrid simulation (RTHS) is a versatile and cost-effective testing method for studying the performance of structures subjected to dynamic loading. RTHS decomposes a structure into partitioned physical and numerical sub-structures that are coupled together through actuation systems. The sub-structuring approach is particularly attractive for studying large-scale problems since it allows for setting up large-scale structures with thousands of degrees of freedom in numerical simulations while specific components can be studied experimentally.The actuator dynamics generate an inevitable time delay in the overall system that affects the accuracy and stability of the simulation. Therefore, developing robust tracking control methodologies are necessary …

Probabilistic Approach To Water, Sediment, And Nutrient Connectivity For Advancing Watershed Modelling, David Tyler Mahoney

Theses and Dissertations--Civil Engineering

The goal of this dissertation is to represent the spatial and temporal domains of water, sediment, and nutrient flux and pathways within fluvial and watershed settings. To complete this goal, we integrate connectivity theory into watershed model structures to simulate water, sediment, and nutrient movement at the fundamental unit they occur. Fluvial-based sediment and nutrient flux is an important driver of global sediment and nutrient budgets, and the quantification of which serves as an ongoing challenge to limnologists, engineers, and watershed managers. Watershed models have been richly developed over the past century, but are currently restrained by problems related to …

A Modeling Approach To Understanding Glyphosate Transport In The Belize River Watershed, Barbara Anmei Astmann

Theses and Dissertations--Civil Engineering

Glyphosate is the most widely used herbicide worldwide and is often transported from application areas to surface water when solubilized in runoff or sorbed to eroded sediment. There is evidence that suggests both glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) may pose a risk to human health, as well as cause adverse effects in the environment. However, consistent monitoring data is still limited, especially in developing countries. Belize is a developing nation with agriculture being a major sector of its economy and is heavily reliant on glyphosate. The widespread use of glyphosate in Belize may be resulting in glyphosate …

Design And Analysis Of A Pavement Marker Detection System, Timothy L. Johnson Ii

Theses and Dissertations--Civil Engineering

Personal injuries and property damage due to the failure of snow-plowable pavement markers which detach from pavement surfaces has led to the development of new all-plastic pavement markers which are located entirely below the planar surface of the pavement. The new all-plastic design pushes existing solutions used to avoid striping over highway reflectors into obsolescence since current solutions operate using electromagnets to sense the metal housings of snow-plowable pavement markers. A replacement solution is currently sought by the highway maintenance industry and three different marker detection methods were developed and tested on real-world highways with both new and aging pavement …

Variance Decomposition Of Forecasted Water Budget And Sediment Processes Under Changing Climate In Fluvial And Fluviokarst Systems, Nabil Al Aamery

Theses and Dissertations--Civil Engineering

Variance decomposition is the partitioning of different factors affecting the variance structure of a response variable. The present research focuses on future streamflow and sediment transport processes projections as the response variables. The authors propose using numerous climate factors and hydrological modeling factors that can cause any response variable to vary from historic to future conditions in any given watershed system. The climate modeling factors include global climate model, downscaling method, emission scenario, project phase, bias correction. The hydrological modeling factor includes hydrological model parametrization, and meteorological variable inclusion in the analysis. This research uses a wide spectrum of data, …

Reliability Assessment And Optimization Of Water Distribution Systems Explicitly Considering Isolation Valve Locations, Erika Hernandez Hernandez

Theses and Dissertations--Civil Engineering

Water distribution systems have changed the landscape of communities through two services: 1) providing water supply for domestic and industrial use, and 2) providing water required to fight fires. However, a substantial portion of the water infrastructure in the country, as many of other public assets built over 50 years ago, are now reaching the end of their useful life; which combined with rapid growth and changes in demographics have placed water distribution pipe networks at a state that requires revitalization. The aging infrastructure along with the growing threat of natural and man-made disruptions have led water utilities to place …

Subsurface Characterization Of Internally Eroded Soils In Karst Using The Cone Penetration Test, Ryan Shamet

Electronic Theses and Dissertations, 2020-2023

Sinkholes are a major geohazard with life-threatening consequences when not properly detected and mitigated. Geologic conditions comprised of soluble bedrock (e.g., limestone or other carbonate-based lithologies) overlain by fine-grained sandy and clayey soils, are known internationally as "karst topography" and is generally characterized by such sinkholes, caves, sinking streams, and highly variable groundwater flow conditions. Karst sinkholes, however, are complex geohazards and are difficult to precisely characterize through geotechnical considerations alone. Deterministic methods (e.g., analytical and numerical solutions) may provide for a more robust analysis of internal soil erosion (known as soil raveling) but have limitations for the practical use …