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Articles 361 - 390 of 7868

Full-Text Articles in Civil and Environmental Engineering

Thermo-Mechanical Stability Analysis Of Hollow Cellular Concrete Block Air Convection Embankments For Cold Regions, H. Wu, X. Zhang, J. Liu Jan 2024

Thermo-Mechanical Stability Analysis Of Hollow Cellular Concrete Block Air Convection Embankments For Cold Regions, H. Wu, X. Zhang, J. Liu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Crushed-rock air convection embankment (ACE), as a highly open-graded porous medium, has been used to mitigate the thaw settlement of pavement structures in permafrost regions. Previous studies have revealed that cellular concrete has significant potential as a cost-effective material for ACE to solve the problem of crushed rock shortage in interior Alaska and improved the thermal stability of pavement structures in cold climates. the design configurations of the hollow cellular concrete block ACE were further designed to maximize the performance benefits and facilitate future implementation and field construction. However, the mechanical behaviors of the proposed structures and ice-rich subgrade were …


Prediction Of Stratified Ground Consolidation Via A Physics-Informed Neural Network Utilizing Short-Term Excess Pore Water Pressure Monitoring Data, Weibing Gong, Linlong Zuo, Lin Li, Hui Wang Jan 2024

Prediction Of Stratified Ground Consolidation Via A Physics-Informed Neural Network Utilizing Short-Term Excess Pore Water Pressure Monitoring Data, Weibing Gong, Linlong Zuo, Lin Li, Hui Wang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Predicting stratified ground consolidation effectively remains a challenge in geotechnical engineering, especially when it comes to quickly and dependably determining the coefficient of consolidation ((Formula presented.)) for each soil layer. This difficulty primarily stems from the time-intensive nature of the consolidation process and the challenges in efficiently simulating this process in laboratory settings and using numerical methods. Nevertheless, the consolidation of stratified ground is crucial because it governs ground settlement, affecting the safety and serviceability of structures situated on or in such ground. In this study, an innovative method utilizing a physics-informed neural network (PINN) is introduced to predict stratified …


Circular Economy Strategies For Reducing Embodied Carbon In Us Commercial Building Stocks: A System Dynamics Modeling Approach, Radwa Eissa, Islam H. El-Adaway Jan 2024

Circular Economy Strategies For Reducing Embodied Carbon In Us Commercial Building Stocks: A System Dynamics Modeling Approach, Radwa Eissa, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Environmental concerns over embodied carbon - which is generated during the extraction, transportation, manufacturing, construction, and disposal of building materials - have been increasing as the industry shifts to renewable energy and grid decarbonization efforts prevail. Commercial buildings, a rapidly growing sector and a major source of embodied carbon, can contribute immensely to the national climate goals by transitioning into a circular economy (CE). Nevertheless, embodied carbon research is rather dispersed, with sparse data on the actual impact of different CE strategies and how they scale on nationwide commercial building stocks. To address this research need, the goal of this …


Quantifying The Impact Of A Constructed Wetland On Downstream Nitrate Concentrations And Loads In The U.S. Midwest, Elliot Anderson, Keith E. Schilling, Craig L. Just, Bong Chul Seo Jan 2024

Quantifying The Impact Of A Constructed Wetland On Downstream Nitrate Concentrations And Loads In The U.S. Midwest, Elliot Anderson, Keith E. Schilling, Craig L. Just, Bong Chul Seo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Constructed wetlands are standard conservation practices used to reduce nitrate loads in agricultural watersheds. Many studies have examined the efficiency of denitrification in wetlands under various scenarios, but quantifying the watershed-scale impact of wetlands on downstream nitrate levels is rarely done using field observations. In this study, we estimated nitrate removal in a constructed wetland in the headwaters of Mud Creek, a HUC12 watershed in eastern Iowa, from May–September 2022 and May–September 2023 (a ten-month period). We also measured nitrate loads at four successive downstream sites, three along Mud Creek and one below its confluence with the larger Cedar River. …


Identifying The Job Characteristics Affecting Construction Firm Employee Turnover Intention, Seog Jae Choi Jan 2024

Identifying The Job Characteristics Affecting Construction Firm Employee Turnover Intention, Seog Jae Choi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Researchers have proved that employees who have the intention to quit the organization, called turnover intention, have decreased productivity and may not fulfill their duties properly. The turnover intention has a negative relationship with the quality of core job characteristics of the organization. As the construction industry has distinctive characteristics compared to other industries, the job characteristics that influence turnover intention need to be explored separately. This study identifies job characteristics of the construction industry that can affect turnover intention. Through the literature review, autonomy, task identity, required skill variety, task significance, justification in assigning work location, and job security …


Achieving Project Objectives And Improving Functions: The Benefits Of Ai And Construction Technologies, Fareed Salih, Islam H. El-Adaway Jan 2024

Achieving Project Objectives And Improving Functions: The Benefits Of Ai And Construction Technologies, Fareed Salih, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Construction Industry Is Increasingly Incorporating Artificial Intelligence (AI) And Construction Technologies Into Projects. However, It Lags Behind Other Industries In Terms Of Digital Transformation. One Of The Reasons For This Disparity Is The Lack Of Evidence-Based Information On AI And Technologies In Construction Projects. Hence, This Research Aims To Comprehensively Understand The Benefits Of AI Techniques And Construction Technologies And Their Role In Achieving Objectives And Improving Functions. To This End, The Authors Followed A Three-Step Research Methodology. Firstly, An Extensive Literature Review Was Conducted To Identify 4 AI Techniques, 13 Construction Technologies, And 28 Benefits Relevant To Their …


Development Of A Particulate Matter Sensor Network For Air Quality Monitoring In Indoor Settings And In Mines, Abdulrahman Bani Jan 2024

Development Of A Particulate Matter Sensor Network For Air Quality Monitoring In Indoor Settings And In Mines, Abdulrahman Bani

Masters Theses

"The importance of indoor air quality (IAQ), especially concerning particulate matter (PM), has become increasingly recognized due to its substantial impact on public health. Individuals spend a significant portion of their time indoors, where PM concentrations can exceed that of outdoors, leading to potential adverse health effects ranging from immediate irritation to long-term respiratory and cardiovascular diseases. The dynamic nature of indoor environments, combined with the diversity of PM sources, presents considerable challenges for effective IAQ monitoring and management. Traditional approaches to IAQ assessment often fall short, lacking the granularity and immediacy required to address these challenges adequately.

This abstract …


Improving Decision-Making Processes In Construction And Infrastructure Bidding: Qualitative And Quantitative Approaches Including Graph Theory, Game Theory, And Machine Learning, Muaz Osman Elzubeir Ahmed Jan 2024

Improving Decision-Making Processes In Construction And Infrastructure Bidding: Qualitative And Quantitative Approaches Including Graph Theory, Game Theory, And Machine Learning, Muaz Osman Elzubeir Ahmed

Doctoral Dissertations

"Construction and infrastructure bidding is a highly competitive process that entails various uncertainties faced by contractors. Contractors weigh various factors to determine the expected benefits of a construction project and decide their bid value. However, the situation is more complex in multi-stage bidding (MSG), where general contractors must account for the bids of their subcontractors and face a greater threat of the winner’s curse (i.e., situation where the winning contractor underestimates the actual cost of the project). As such, bidding-related complexities, risks, and uncertainties, if uncontrolled, can lead to the rise of claims and disputes between stakeholders. Existing research falls …


Evaluating Friction Characteristics Of High Friction Surface Treatment Application Under Varied Polishing And Slippery Conditions, Alireza Roshan, Magdy Abdelrahman Jan 2024

Evaluating Friction Characteristics Of High Friction Surface Treatment Application Under Varied Polishing And Slippery Conditions, Alireza Roshan, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The frictional attributes of high friction surface treatment (HFST) play a crucial role in ensuring optimal traffic safety, particularly in wet weather conditions. Friction consists of two important components: adhesion and hysteresis. This research focuses on evaluating these essential factors in HFST using two different aggregates and two distinct sizes by considering various abrasion and polishing methods. To isolate these components for assessment, testing was carried out under various slippery conditions, including dry, wet with water, and wet with water + soap. The inclusion of liquid hand soap in the test procedure effectively minimized or even eliminated the adhesion component's …


Agent-Based Modeling For Understanding Incentives Associated With Distributed Solar Generation, Gasser Ali, Islam H. El-Adaway Jan 2024

Agent-Based Modeling For Understanding Incentives Associated With Distributed Solar Generation, Gasser Ali, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Distributed solar generation (DSG), such as residential photo-voltaic (PV) solar panels, offers many benefits to consumers and can improve the sustainability and resilience of the electric power infrastructure. As such, many local and national authorities implemented policy incentives, such as rebates and loans with reduced interests, to promote the adoption of DSG. However, the increasing penetration of DSG is creating new obstacles for system operators due to the uncertainty in forecasting electrical power demand. There is a need to investigate how incentives affect DSG adoption. To achieve that goal, a complex system-of-systems (SoS) model is developed using agent-based modeling (ABM). …


System Dynamics Modeling For Investigating The Retention Of Skilled Labor In The Construction Market, Tamima Elbashbishy, Islam H. El-Adaway Jan 2024

System Dynamics Modeling For Investigating The Retention Of Skilled Labor In The Construction Market, Tamima Elbashbishy, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Limited skilled labor has been one of the greatest challenges facing the construction industry, especially after COVID. In 2019, around 80% of contractors in the US reported problems in hiring enough skilled workers. Labor retention has been one of the major contributors to skilled labor shortages in construction. The goal of this paper is to study the impact of key construction industry characteristics and economic conditions on skilled labor shortages. This goal is achieved by simulating the flow of skilled workers throughout the construction industry. To this end, a system dynamics (SD) model was developed to represent skilled labor and …


Investigating Price Fluctuation Transmission Among Construction Materials, Mohamad Abdul Nabi, Islam H. El-Adaway, Rayan H. Assaad Jan 2024

Investigating Price Fluctuation Transmission Among Construction Materials, Mohamad Abdul Nabi, Islam H. El-Adaway, Rayan H. Assaad

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Generally, Fluctuation In One Material's Price Can Cause A Series Of Chain Reactions In The Supply Chain System, Known As Price Fluctuation Transmission, As All Materials Are Interconnected And Interrelated. None Of The Previous Studies Have Investigated Price Fluctuation Transmission Among All Construction Materials. This Paper Aims To Fill This Gap In Knowledge. The Authors Collected Producer Price Index (PPI) Data For 16 Construction Materials, Modeled The Relationship Between Each Pair Of Materials Using Vector Autoregression Technique, And Validated The Causality Using Granger Causality Test. Network Analysis Was Performed To Identify The Price Fluctuation Transmission Capacity, Susceptibility, And Intermediatory Capacity …


A Concept Of Producing Aluminum In-Situ On The Moon Through Molten Salt Electrolysis, Jacob N. Ortega, Jeffrey Smith, Fateme Rezaei, David Bayless, William Schonberg, Daniel Stutts, Daoru Han Jan 2024

A Concept Of Producing Aluminum In-Situ On The Moon Through Molten Salt Electrolysis, Jacob N. Ortega, Jeffrey Smith, Fateme Rezaei, David Bayless, William Schonberg, Daniel Stutts, Daoru Han

Materials Science and Engineering Faculty Research & Creative Works

This paper presents a concept of producing aluminum in-situ on the lunar surface, namely, the Lunar In-Situ Aluminum Production through Molten Salt Electrolysis (LISAP-MSE) method developed at Missouri University of Science and Technology. This paper aims to demonstrate the use of electro-deoxidation to reduce aluminum oxide (i.e., alumina) into aluminum and oxygen gas via electrolysis in a molten salt bath for the production of aluminum on the Moon. It is shown that with a steady supply of hydrogen chloride, this in-situ resource utilization (ISRU) method could supply several necessary materials consumed in the electro-deoxidation process except hydrogen chloride to produce …


Skilled Worker Shortage Across Key Labor-Intensive Construction Trades In Union Versus Nonunion Environments, Tamima Elbashbishy, Islam H. El-Adaway Jan 2024

Skilled Worker Shortage Across Key Labor-Intensive Construction Trades In Union Versus Nonunion Environments, Tamima Elbashbishy, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Skilled labor plays a crucial role in ensuring that construction projects are completed on time, within budget, and to the required standards of quality and safety. However, the construction industry has been facing a labor shortage in recent years, which poses a significant challenge to the industry's growth and sustainability. Therefore, it is important to examine the characteristics of the construction skilled labor market to understand the factors that contribute to the shortage of skilled workers and develop strategies to address the issue. This paper fills this knowledge gap. To this end, the authors (1) collected and processed project documentation …


An Agent-Based Cellular Automaton Simulation Model To Study Worker Safety Behavior On Construction Sites: The Impacts Of Different Social Influence Rules, Rayan H. Assaad, Mohamad Abdul Nabi, Ghiwa Assaf, Islam H. El-Adaway Jan 2024

An Agent-Based Cellular Automaton Simulation Model To Study Worker Safety Behavior On Construction Sites: The Impacts Of Different Social Influence Rules, Rayan H. Assaad, Mohamad Abdul Nabi, Ghiwa Assaf, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The unsafe behavior of the construction workforce is one of the leading causes of accidents in the construction industry. It has been shown that construction laborers perceive the safety behavior of their co-workers and adjust their personal safety attitudes accordingly. Thus, there has been an increasing attention to studying the impacts of the social influence and norms on the safety behavior of construction workers. While existing studies examined the factors that influence the safety behavior of the construction workforce, there is little-to-no research that specifically focused on modeling the role of social influence on the safety behavior of the workers. …


A Contractual Approach To Resolving Disputes Arising From Failure To Achieve Green Certification, Bahaa Chammout, Islam H. El-Adaway Jan 2024

A Contractual Approach To Resolving Disputes Arising From Failure To Achieve Green Certification, Bahaa Chammout, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Green Construction Is An Approach To Reducing The Environmental Impact Of Resource-Intensive Construction. Several Certification Systems Have Been Devised And Are Globally Recognized To Provide Green Building Rating Frameworks. While A Building Can Be Designed To Achieve A Green Rating, The Rating Is Achieved Based On The Completed Facility's Actual Measured Performance. There Had Previously Been Limited Attempts To Give An In-Depth Examination Of The Remedies For Unrealized Green Ratings. As Such, This Paper Addresses This Knowledge Gap Using A Multistep Research Methodology. First, The Authors Analyzed And Classified The Nature Of Damages Resulting From Failed Green Certification Under The …


Assessing The Impact Of Skilled Labor Shortages On Project Cost Performance, Tamima S. Elbashbishy, Islam H. El-Adaway Jan 2024

Assessing The Impact Of Skilled Labor Shortages On Project Cost Performance, Tamima S. Elbashbishy, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Over The Past Decade, There Has Been A Notable Increase In Skilled Labor Shortages Within The Construction Industry. This Shortage Has Numerous Negative Consequences On Construction Projects, Such As Delays In Completion, Compromised Quality, And Higher Costs. Therefore, The Goal Of This Paper Is To Examine The Extent Of Skilled Labor Shortages Observed Throughout The Industry And Their Impact On The Cost Performance Of Construction Projects. To Achieve This Goal, The Authors Identified 10 Key Construction Trades That Heavily Rely On Skilled Labor. Subsequently, An Industry Survey Was Conducted To Measure The Extent Of Skilled Labor Shortages, As Well As …


Predicting Construction Costs Under Uncertain Market Conditions: Probabilistic Forecasting Using Autoregressive Recurrent Networks Based On Deepar, Ghiwa Assaf, Rayan H. Assaad, Islam H. El-Adaway, Mohamad Abdul Nabi Jan 2024

Predicting Construction Costs Under Uncertain Market Conditions: Probabilistic Forecasting Using Autoregressive Recurrent Networks Based On Deepar, Ghiwa Assaf, Rayan H. Assaad, Islam H. El-Adaway, Mohamad Abdul Nabi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Projects Often Experience Cost Overruns Due To Market Uncertainty And Price Escalations. Traditional Cost Estimation Methods That Rely On Point Estimation Are Incapable Of Providing Prediction Intervals As Well As Probabilistic Assessment. Thus, There Is Need For An Innovative Approach To Predict The Changes And Uncertainties In Construction Material Costs. This Paper Proposes A Novel Stochastic Model To Estimate Construction Material Costs By Applying Probabilistic Forecasting Using Autoregressive Recurrent Networks. First, Price Data Was Collected For Four Different Construction Materials. Second, Data Was Divided Into A Training Set (Pre-COVID-19) And A Testing Test (Post-COVID-19). Third, The State-Of-The-Art DeepAR Algorithm Was …


Circular Economy Strategies For Decarbonization Of The Built Environment Value Chain Scope 3 Emissions: A Network Analysis, Radwa Eissa, Islam H. El-Adaway Jan 2024

Circular Economy Strategies For Decarbonization Of The Built Environment Value Chain Scope 3 Emissions: A Network Analysis, Radwa Eissa, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

With The Anticipated Growth In Construction Activities, Minimizing Value Chain Emissions, Including Those Attributed To Activities Beyond An Organization's Direct Control - Aka "Scope 3" Emissions, And Adopting Circular Economy (CE) Practices Have Become Critical To Attaining The 2050 Climate Goals. Extant Literature Lacks A Value-Chain-Comprehensive Set Of CE Strategies On One Hand, And An Analysis Of Their Actual Project Applications On The Other. This Research Aims To Build A Holistic Portfolio Of CE Actionable Strategies That Span Across The Entire Built Environment Value Chain, Analyzing Their Extent Of Implementation And Interlinkages Within The Literature Versus Actual Projects. To This …


Photogrammetry-Based Method For Measuring Volume Changes Of Soil Specimens During Critical Phases Of Triaxial Testing, Sara Fayek, Xiong Zhang, Pingxin Xia Jan 2024

Photogrammetry-Based Method For Measuring Volume Changes Of Soil Specimens During Critical Phases Of Triaxial Testing, Sara Fayek, Xiong Zhang, Pingxin Xia

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Triaxial tests has been routinely used to measure the stress–strain relationship for geomaterials. During triaxial testing, many sources of errors that cannot be completely avoided but are often ignored or approximated using empirical equations. This paper presents a systematic investigation of soil volume change, volume strain nonuniformity, and cross-sectional calculation along the specimen during triaxial testing using a photogrammetry-based method. Consolidated drained triaxial tests were performed in which two parallel measurements were taken: (1) relative volume using the conventional triaxial testing and (2) absolute volume using the photogrammetry-based method. The difference in the observed volume and void ratio measurements between …


Scshm Benchmark Study On Bridge In-Service Structural Monitoring, Maria Pina Limongelli, Doug Thomson, Sreenivas Alampalli, Aftab Mufti, Thomas Schumacher, Luca Martinelli, Othmane Lasri, Harry Shenton, Genda Chen, Mohammad Noori, Farnaz Raeisi, Ahmed Silik, Ji Dang, Ray Hoemsen Jan 2024

Scshm Benchmark Study On Bridge In-Service Structural Monitoring, Maria Pina Limongelli, Doug Thomson, Sreenivas Alampalli, Aftab Mufti, Thomas Schumacher, Luca Martinelli, Othmane Lasri, Harry Shenton, Genda Chen, Mohammad Noori, Farnaz Raeisi, Ahmed Silik, Ji Dang, Ray Hoemsen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The mission of the Society of Civil Structural Health Monitoring (SCSHM, previously known as ISHMII) is to advance the understanding and application of structural monitoring methodologies for the management of civil infrastructure systems. To enable comparative and contrasting studies of various monitoring issues and technologies, the SCSHM Committee on Data-Enhanced Infrastructures Management (DEIMC) identified the need for benchmark problems in the areas of bridge and building structural monitoring. This article reports and briefly discusses the first benchmark study on in-service structural monitoring of bridges that was developed in collaboration with the University of Manitoba, and presents the structure details, study …


Performance Of Smart Shear Keys In Concrete Bridges Under Tsunami Loading: An Experimental Study, Haibin Zhang, Xinzhe Yuan, Genda Chen, Pedro Lomonaco Jan 2024

Performance Of Smart Shear Keys In Concrete Bridges Under Tsunami Loading: An Experimental Study, Haibin Zhang, Xinzhe Yuan, Genda Chen, Pedro Lomonaco

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Bridges have recently been exposed to an increasing number of natural hazards such as earthquakes and tsunamis. These extreme events have resulted in transverse offsets, overturning moments, and even dropping-off of superstructures due to their weak connection to substructures. These outcomes are potentially prevented or mitigated by developing and deploying sliding, modular, adaptive, replaceable, and two-dimensional (SMART) shear keys as fuse elements between superstructures and substructures. The novelty of SMART shear keys is to enable an adaptive control of both the force and displacement of bridges under different types of loads. In this study, the performance of SMART shear keys …


Predicting High-Impact Research In The Construction Engineering And Management Domain Using Computational Machine Learning, Islam H. El-Adaway, Gasser G. Ali, Muaz O. Ahmed, Radwa Eissa, Mohamad Abdul Nabi, Tamima Elbashbishy, Ramy Khalef Jan 2024

Predicting High-Impact Research In The Construction Engineering And Management Domain Using Computational Machine Learning, Islam H. El-Adaway, Gasser G. Ali, Muaz O. Ahmed, Radwa Eissa, Mohamad Abdul Nabi, Tamima Elbashbishy, Ramy Khalef

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Construction engineering and management (CEM) domain covers multiple evolving sub-disciplines and directions. To understand those directions, numerous research efforts have conducted scientometric analysis of publications to explore their significance and impact. Despite their valuable insights, such research endeavors have been limited to exploratory analyses, whereas no previous attempt has been conducted to predict the future impact of research in CEM. This study fills this knowledge gap by performing a predictive analysis of citation metrics of publications in CEM using machine learning (ML). The developed model was trained on a dataset of 93,868 publications using an XGBoost algorithm. Testing showed that …


Trends And Opportunities For Material Information Sharing: Applying Bim To Support Supply Chain Management In Construction Projects, Seog Jae Choi, Fernanda Leite Jan 2024

Trends And Opportunities For Material Information Sharing: Applying Bim To Support Supply Chain Management In Construction Projects, Seog Jae Choi, Fernanda Leite

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Due to dynamic organizations and unexpected conditions on project sites, the construction industry has suffered from schedule and cost overruns. Researchers have applied building information modeling (BIM) and supply chain management (SCM) concepts to integrate diverse stakeholders, and further, improve efficiency in construction projects. BIM can support supply chain integration (SCI) by providing reliable up-to-date information on a project, which reduces resource waste and completes the project as planned. Specifically, sharing updated material information, including the state of material fabrication, current location, each material's due date on site, and site inventory status, is crucial for successful project execution because such …


Low-Shrinkage Fiber-Reinforced Concrete For Infrastructure Construction And Rehabilitation, Jingjie Wei Jan 2024

Low-Shrinkage Fiber-Reinforced Concrete For Infrastructure Construction And Rehabilitation, Jingjie Wei

Doctoral Dissertations

"The aim of this study is to develop two classes of low-shrinkage high-performance concrete (HPC): fiber-reinforced super workable concrete (FR-SWC) for infrastructure construction and fiber-reinforced self-consolidating concrete (FR-SCC) for repair applications. HPC with excess content of shrinkage mitigation materials (SMMs), including shrinkage-reducing admixture (SRA), superabsorbent polymer (SAP), and expansive agent (EA) has a detrimental effect on mechanical performance. These classes of HPC were optimized to reduce shrinkage, enhance mechanical properties, and improve durability. The effect of fiber type (macro synthetic fiber, MSF; 5D steel fiber, 5D; 80% 3D + 20% short steel fibers; STST), SMMs, and plastic viscosity on bond …


Investigation Of Wide Beam And Interfacial Shear Transfer In Reinforced Concrete Structures, Nikkolas Edgmond Jan 2024

Investigation Of Wide Beam And Interfacial Shear Transfer In Reinforced Concrete Structures, Nikkolas Edgmond

Doctoral Dissertations

"The use of reinforced concrete (RC) allows for unique designs of structural elements and connections because of the ability to vary the geometry and reinforcement detailing with ease. However, this freedom in the design process can lead to specialized conditions that have not been extensively studied by means of experimental testing. This is especially true for components or regions of components that are subjected to high shear loads, which are susceptible to undesirable and brittle failures. While many studies have been conducted to investigate the shear behavior of RC structural members and components to determine the critical design parameters, these …


Enhancing Pricing Practices Of Subcontractors: A Comparative Analysis Using Simulation Modeling, Muaz O. Ahmed, Islam H. El-Adaway, Kalyn T. Coatney Jan 2024

Enhancing Pricing Practices Of Subcontractors: A Comparative Analysis Using Simulation Modeling, Muaz O. Ahmed, Islam H. El-Adaway, Kalyn T. Coatney

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The construction industry often relies on subcontracting, where subcontractors bid for portions of a project before general contractors bid for the entire project in a process referred to as multi-stage bidding (MSG). MSG can be complex, and winning bidders may be burdened with underestimating their bids and encountering the winner's curse. Despite various studies investigating this issue, further research is necessary to examine bidding strategies for subcontractors. This paper addresses this research need by exploring and comparing how bidding strategies based on reinforcement learning and game theory could aid subcontractors in mitigating the winner's curse in MSG. The authors used …


Exploring The Root Factors Impacting Work Zone Accidents: A Mixed-Methods Study, Bahaa Chammout, Muaz O. Ahmed, Islam H. El-Adaway Jan 2024

Exploring The Root Factors Impacting Work Zone Accidents: A Mixed-Methods Study, Bahaa Chammout, Muaz O. Ahmed, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Work Zones Are Vital For Improving Infrastructural Utilities Yet Pose Significant Dangers For Workers And Drivers Who Are Often Unfamiliar With These Areas. Prior Research Examined Various Aspects Of Work Zone Accident Causation; However, The Interrelationships And Critical Combinations Among The Contributing Factors Have Not Been Fully Analyzed. This Study Aims To Identify The Underlying Factors Contributing To Work Zone Accidents And Evaluate The Different Combinations Among Them. To This Purpose, Accident Factors Were Derived From A Total Of 133 Research Articles Addressing Work Zone Safety. Social Network Analysis (SNA) And Clustering Were Used To Comprehensively Model The Identified Factors. …


Kiloton Class Isru Systems For Lo2/Lch4 Propellant Production On The Mars Surface, Steven R. Oleson, Elizabeth Turnbull, Julie Kleinhenz, Wesley Johnson, Ryan Grotenrath, Nicholas Uguccini, Benjamin Abshire, Lee Mason, Thomas Packard, Anthony Colozza, John Z. Gyekenyesi, James Fittje, Stephen Hoffman, Leslie S. Gertsch Jan 2024

Kiloton Class Isru Systems For Lo2/Lch4 Propellant Production On The Mars Surface, Steven R. Oleson, Elizabeth Turnbull, Julie Kleinhenz, Wesley Johnson, Ryan Grotenrath, Nicholas Uguccini, Benjamin Abshire, Lee Mason, Thomas Packard, Anthony Colozza, John Z. Gyekenyesi, James Fittje, Stephen Hoffman, Leslie S. Gertsch

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

As part of the 2023 strategic analysis cycle to explore the trade space, the NASA Mars Architecture Team wanted to explore what it takes to produce in situ on Mars many hundreds of tons of propellants for a large all-chemical transportation system. The conceptual operations and design of the LO2/LCH4 in situ resource utilization (ISRU) water acquisition, propellant production and liquification system was assigned to the NASA Compass concurrent engineering team with support from various NASA ISRU, cryogenic fluid management, and surface power experts. The conceptual point design examined one case producing 300 t of LO2 …


Beneficiation Of Lunar Regolith Simulants Through Electrostatic Sieving And Magnetic Separation, Peter Bachle, Jeffrey Smith, Fateme Rezaei, David Bayless, William Schonberg, Daoru Han Jan 2024

Beneficiation Of Lunar Regolith Simulants Through Electrostatic Sieving And Magnetic Separation, Peter Bachle, Jeffrey Smith, Fateme Rezaei, David Bayless, William Schonberg, Daoru Han

Materials Science and Engineering Faculty Research & Creative Works

In the light of future development of lunar structures, in-situ feldspar beneficiation is imperative for metal extraction. This research incorporates the tandem use of electrostatic sieving and magnetic separation for collecting a specific size range and mineral composition from lunar soil that optimizes subsequent chemical processing. While earlier works focused on silt-sized particles, this work expands that range up to medium-grained sand with a greater variety of potential lunar regolith compositions. This work shows that a 2.5 kV, 7 Hz to 30Hz frequency, single-phase square wave can lift silt and fine sand for collection. This lifting is successful directly from …