Civil Engineering Commons^™

Non-Contact Acoustic Emission Detection Of Rail Defects Using Air-Coupled Sensors, Lei Jia

UNLV Theses, Dissertations, Professional Papers, and Capstones

Rail defects, whether internal or external, present significant safety risks. Acoustic Emission (AE) technology has emerged as a promising technique for monitoring damage progression and detecting these rail defects. This project addresses this critical concern by testing air-coupled optical microphones for non-contact AE detection. The goal of this research is to investigate AE signal characteristics using both rail-mounted and vehicle-mounted methods, establishing the understanding of AE signals in relation to defects and their effectiveness in identifying them.

This research focused on investigating air-conduct sensors in the lab-controlled pencil lead break (PLB) test. The objective was to evaluate the propagation characteristics …

Prediction Of Cost And Schedule Changes In Transportation Projects Through Historical Bid And Change Order Document Analysis – Using Oklahoma Dot Project Cases., Rabin Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Construction bid documents encompass project specifications, drawings, schedules, and other critical details and are the foundation for project bidding and execution. Accurate bid documents are essential to ensure project bids are competitive, realistic, and aligned with requirements. However, bid documents are susceptible to risks from various sources. Failure to identify and rectify these risks can result in inaccurate cost estimates and higher bids. Therefore, identifying and resolving risks within bidding or contract documents are of utmost importance. While prior research has shed light on potential risk factors within the bid documents, a noticeable gap remains in the literature regarding identifying …

Impacts Of Stream Bed Adjustment On Local Bridge Morphology At Highway 281, Molly G. Likins

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

Nebraska sand-bed rivers have long been a part of sediment transport studies and have been used in the development of numerous well-known empirical bedload equations. Some of these studies have shown how adjustments in streambed elevation led to changes in local stream morphology. The sand-bed rivers of Nebraska are highly susceptible to such changes due to their wide, shallow cross-sections and erodibility. The objective of our study is to synthesize a hydrodynamic model with high-resolution field data and improved methods of representing sediment transport to better predict both short and long-term channel adjustments for an aggraded sand-bed river.

The field …

Numerical Study On The Behavior Of Natural And Recycled Aggregate Concretes, Shahriar Mardpour

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

This thesis investigates the mechanical behavior of natural and recycled aggregate concretes (NAC and RAC) using a multi-phase numerical approach to predict performance. Growing interest in sustainable materials has led to using recycled concrete aggregates (RCA) to replace natural aggregates, creating Recycled Aggregate Concrete (RAC). Due to their different structural components, RAC and NAC exhibit varying mechanical properties, particularly in strength and durability.

This study validated tension and bending (flexural) test models by comparing numerical results with similar models from the literature. Following validation, a multi-phase approach modeled NAC and RAC for the bending (flexural) and tension tests, providing a …

Development And Evaluation Of Highly Thixotropic Uhpc Mixtures For Bridge Overlay Applications, Akbota Aitbayeva

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

Ultra-high-performance concrete (UHPC) is an advanced construction material renowned for its exceptional strength and durability. However, conventional UHPC is typically self-consolidating, making it unsuitable for bridge deck overlay applications due to challenges posed by potential surface slopes. UHPC overlay construction requires a highly thixotropic material that not only responds well to vibration but also maintains workability over an extended period and remains stable on sloped surfaces. Despite the complex rheological properties of highly thixotropic UHPC, limited testing methods are available to effectively assess the workability and rheology of overlay mixtures. To address this gap, the present study provides a comprehensive …

Exploring Variably Saturated Flow Formulations For Modflow: Implementing A Fully 3d Richards' Equation In Modflow 6, Sebastian Vazquez-Gasty

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

This thesis explores the implementation of a fully 3D Richards’ equation solution into MODFLOW 6 to solve for saturated/unsaturated flow. Currently, MODFLOW 6 has limited capability for solving unsaturated zone flow problems by using the Unsaturated Zone Flow (UZF) package, which neglects capillarity and assumes vertical 1-dimensional flow. Various formulations of the Richards’ equation were first evaluated for their strengths and weaknesses. Various numerical solution approaches to Richards’ equation were also studied to understand the robustness and efficiency of different approaches and to select one that would best fit into the MODFLOW 6 framework. The MODFLOW 6 framework was also …

Performance Of Geopolymer Concrete Incorporating Recycled Aggregates And Glass Fibers, Mohammed Abughali

Thesis/ Dissertation Defenses

This study aims to investigate the potential use of geopolymer concrete (GC) incorporating recycled concrete aggregates (RCA) and glass fibers (GF) as a sustainable alternative to traditional cement-based concrete. It comprehensively evaluated the impact of RCA and GF on the fresh, physical, mechanical, and durability properties. A blended precursor binder consisting of ground granulated blast furnace slag and fly ash was utilized. To mitigate the challenges associated with the brittle behavior and low crack resistance of GC, mainly when incorporating RCA, two types of GF were used. Type A had a length of 24 mm, while Type B exhibited a …

Integrated Sustainability Analysis Of A Shared Micro-Mobility System In University Campus: Life-Cycle Assessment And User Impact Study Of Electric Scooters, Md Afif Rahman Chowdhury

LSU Master's Theses

The objective of this study is to evaluate the environmental, economic, and social impacts of implementing e-scooter technology on the LSU campus. The study is structured into three main parts: (1) an environmental life-cycle assessment of e-scooters, (2) a comparative environmental and economic impact assessment of e-scooters, cars, and campus shuttle buses, and (3) a comprehensive survey of e-scooter users to assess their characteristics, satisfaction levels, and comfort while using e-scooters on the LSU campus.

To achieve the objectives of the study, a life-cycle assessment (LCA) was conducted to assess the environmental sustainability of e-scooters, encompassing all stages from raw …

Next Generation Permeable Pavement For Enhanced Durability And Functionality, S M Tanvir

LSU Master's Theses

Porous Asphalt Concrete (PAC), also known as Open-Graded Friction Course (OGFC), is known for its high permeability, which provides benefits such as enhanced rainwater drainage, improved skid resistance, and reduced hydroplaning risks. These characteristics are due to its high air void content, allowing water to flow through the pavement and reducing splash, spray, and noise compared to conventional asphalt mixes. However, this high air void content also contributes to durability concerns, such as raveling, stripping, and clogging, which can reduce service life and increase costs, making OGFC more expensive than conventional asphalt mixtures.

This research focuses on identifying the failure …

Geotechnical Characterization Of Saline Sabkha Soil Of Abu Dhabi, Uae, And Its Stabilization Using Steel Slag And Sodium Silicate, Ahmed Maher Abdulla

Thesis/ Dissertation Defenses

Saline sabkha soil is widely distributed across the Abu Dhabi coastal regions of the UAE. These soils are associated with geotechnical problems that principally emerge from the heterogeneous nature of the soil and its high soluble salt content. Upon exposure to fresh water, the soluble salt dissolves, resulting in loss of the bond that once cemented the soil particles. In addition, the volume occupied by the salt minerals becomes part of the voids between the particles. This process results in a weak and loose soil structure of lower bearing capacity that is ready to collapse upon being subjected to loads. …

Float: A Multi-Scale Flood Loss Assessment Tool Developed From Experimentally Derived Material Damage, Anna Katya Opel

Doctoral Dissertations

Current practice of flood loss prediction presents limitations in accurately predicting building flood losses at multiple scales. While whole-building estimates can more accurately predict high-level losses (i.e., large groups of buildings), a significant analysis error is revealed with small-scale (i.e., individual, or small groups of buildings) investigation. The novel approach of collecting experimental flood data to support damage estimation has provided sufficient evidence that current damage models can and do under or overestimate loss. This research has developed a multi-scale approach to assessing flood losses based on experimentally derived material damage. The methodology is stored and accessible in a multi-scale …

Integrating Gis And Ca-Markov Model To Study Urban Dynamics Of Salem, India In Terms Of Pattern, Intensity And Direction, Linda Theres B

Theses and Dissertations

Urban populations have grown substantially in the modern era and the information age as people seek better living prospects. Currently, more than half of the world's population resides in the cities. Such growth must be monitored to ensure that people enjoy the boons of urban spaces, not the banes. Recognising the significance of urban studies, several researchers have attempted to analyse and predict urban dynamics using remote sensing, Geographic Information Systems, and machine learning methods. However, certain limitations exist, especially in improving the CAMarkov model's prediction performance. In addition, studies have suggested that growth characteristics, such as pattern, intensity, and …

Anti-Corrosion Performance Of Magnesium Potassium Phosphate Cement Coating On Steel Reinforcement: The Effect Of Boric Acid, Fan Zhang, Jihui Qin, Kangyi Cai, John J. Myers, Hongyan Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

It has recently been found that magnesium potassium phosphate cement (MKPC) paste coating applied on the surface of steel reinforcement can effectively retard the onset of corrosion and suppress corrosion reactions. However, the fast-setting nature of MKPC—which is a merit in repair—can be problematic in a practical engineering process of coating the steel reinforcement with MKPC paste. To address this problem, boric acid (H₃BO₃) was added as a retarder in an MKPC formulation to prolong the setting time. This work investigated the impact of boric acid (at 5% by weight of MgO) on the anti-corrosion performance …

Unlocking Telecommuting Patterns Before, During, And After The Covid-19 Pandemic: An Explainable Ai-Driven Study, Adedolapo Ogungbire, Suman Kumar Mitra

Civil Engineering Faculty Publications and Presentations

The COVID-19 pandemic has instigated a global paradigm shift in employment practices, precipitating a widespread transition to telework. While past events had no long-lasting effect on the continued working conditions of the population, it is unclear what a prolonged need for telecommuting on such a nationwide scale would continue to have on the working population. This study uses an explainable artificial intelligence approach to investigate the changes in those telecommuting across three periods: i) pre-pandemic, ii) pandemic, and iii) post-pandemic periods. Machine learning methods, including decision trees, random forest, extreme gradient boost, naïve Bayes, and artificial neural networks, were developed …

The Effects Of Wildfires On The Mental And Physical Health Of School-Age Children In North America: A Scoping Review, Sarah Oerther, Sarah Manspeaker, Alison Wix, Daniel Oerther, Carmen Marsit

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Background: Wildfires are occurring more often and with greater intensity, leading to longer and harsher fire seasons. As a result, children are more frequently exposed to wildfire smoke, which increases their risk of mental and physical health effects. Purpose: The purpose of our scoping review is to explore the current literature on what is known about the direct and indirect impacts of wildfires on the mental and physical health of school-age children in North America (5 to 18-year-olds). Methods: A health sciences librarian-assisted literature search, with input from the research team, was performed. Results: A total of 16 studies were …

Building Services Engineering November/December 2024

Building Services Engineering

No abstract provided.

The Use Of Locally Available Materials Towards Urban Planning For Sustainable Construction: The Case Of Gondar-Ethiopia, Kidist Dereje

Tanzania Journal of Engineering and Technology (TJET)

The city of Gondar in northern Ethiopia has a rich history that is connected to urban planning and construction. From the era of the Fasiledes that built masonry castles, Italian colonialism that zoned the city on racial boundaries and the post-colonial planning that wanted a more global standard, Gondar has been subjected to different planning and construction methods. This evolution however, has brought about challenges related to the sustainability of the construction industry and the communities within the city. This paper analyses the relationship between urban planning and use of local construction materials to attain sustainable development of the city. …

Relationship Between Historic Evolution, Urbanization And Mobility In Ibadan, Nigeria, Aisha Adams

Tanzania Journal of Engineering and Technology (TJET)

Ibadan is said to be the biggest indigenous city in Nigeria with a population of about 4.04 million, making it the third largest city in the country after Lagos and Kano. Since its founding in 1829, Ibadan has experienced urban evolution that is mostly unguided. With its high fertility rate, population growth and rural-to-urban migration, Ibadan has experienced significant urban sprawl that has resulted in challenges in urban mobility especially to the lower-income earners. This study looks at the relationship between urban planning, urbanization and mobility in the city of Ibadan. The study found that lack of integrated land use …

Transport Mobility Analysis For Informal Settlements In Dar Es Salaam, Tanzania, Fatma Kassim Mohamed

Tanzania Journal of Engineering and Technology (TJET)

Dar es Salaam is one of the world’s fastest growing cities and is expected to be the third largest by 2100 with a population of 76 million. Dar es Salaam city is made of multiple neighbourhoods that are very diverse in terms of socio-economic status, gender, age and prevalent activities. One of the biggest challenges facing the city of Dar es Salaam is urban sprawl due to informal settlements that in turn leads to very long travel time and hinders equal mobility and accessibility of labour and goods. This study found that the current mobility vision for Dar es Salaam …

Urbanization And Urban Sprawl In The Post-Colonial Era Douala City, Cameroon, Sylvia Munisi

Tanzania Journal of Engineering and Technology (TJET)

The history of the port city of Douala spans pre-colonial period, colonial period of the Germans and French occupation, the post-colonial era and the contemporary situation with continuous occupancy of the coastal environment. This article looks at the relationship between the history of the city of Douala to the resulting urban situation focusing on governance structure as well as rapid urbanization. The findings show that governance structure allowing for a duality of modern political system and traditional cultural system of kingships and chiefdoms has an effect to the resulting urban sprawl. Moreover, rapid urbanization under this condition has an overall …

The Influence Of Planning And Architectural Styles On The Sustainability Of The City Of Kumasi, Ghana, Elom Ayeke

Tanzania Journal of Engineering and Technology (TJET)

The city of Kumasi that was once dubbed the ‘Garden City of West Africa’ was founded in the late 17th century and served as the seat of government for the medieval Greater Asante Union. It later served as a commercial hub for the British Colony after undergoing massive transformation in the first two decades of the 19th century. Post-independence, the city went through various urban planning projects that mostly targeted social development. The architecture of Kumasi has also been changing through different periods of its history. This article examines the relationship between the evolution of the city of Kumasi through …

Investigating The Relationship Between History, Urbanization And Wealth Gap In Johannesburg, South Africa, Abdallah F. Kaamah

Tanzania Journal of Engineering and Technology (TJET)

The city of Johannesburg is the largest city in South Africa and named as one of the economic drivers of the country. However, the city has the widest wealth gap in the country. This article examines the relationship between historical occurrences, urbanization, and the resulted wealth disparity in Johannesburg and look at the mitigation measures. The findings point to the wealth disparity in the city as a multifaceted problem influenced by historical, urbanization, and political variables. Comprehensive and multifaceted policy initiatives are required to address the structural causes of inequality and the urgent needs of vulnerable populations to close the …

Design Of End Bent Piles For Downdrag, Tanna Frye

USF Tampa Graduate Theses and Dissertations

Embankments are commonly used for bridge approaches, with mechanically stabilized earth (MSE) walls being the preferred choice in Florida. However, the construction of embankments leads to the settlement of the underlying soil, regardless of soil type. When piles are driven before embankment construction, the initial settlement of the original soil creates relative movement between the pile and the surrounding soil, introducing frictional forces. When the existing soils move downward relative to the pile, a downward-oriented side shear known as downdrag is introduced. While downdrag is addressed in current codes and textbooks, it is often only briefly mentioned and primarily in …

Advancing Data-Driven Disaster Debris Characterization And Quantification, Jasmine Bekkaye

LSU Doctoral Dissertations

Natural hazards generate tremendous amounts of debris that negatively impact communities and overwhelm waste management infrastructure. The challenge in disaster debris planning and management stems from inconsistent and scarce post-disaster debris quantity data due to the chaotic nature of recovery operations. This leads to a limited understanding of key factors influencing disaster debris generation across hazards and regions, hindering the accuracy and efficiency of modeling. With the increasing availability of comprehensive post-disaster waste datasets, the capacity to understand debris generation is expanding. This dissertation aims to fill knowledge gaps on disaster debris generation as follows: (1) investigate existing technologies for …

Influence Of Concrete Jacketing On The Performance Of Steel Columns Under Blast Induced Progressive Collapse, Hanan Eltobgy Prof., Mohamed Saeed Refaey Dr., Mohamed Ahmed Aboshok Dr., Ahmed Emadel-Din Abdel-Aal Eng.

Journal of Engineering Research

This study investigates the influence of concrete jacketing on the performance of steel columns subjected to blast loading, which can lead to progressive collapse. Using Finite Element Method (FEM) simulations, the research evaluates concrete-encased steel columns with different concrete cover thicknesses to measure their resistance to lateral displacements induced by blasts. Findings reveal that increasing the thickness of the concrete cover markedly improves the column's ability to withstand such loads. The study also highlights that steel has better energy dissipation properties than concrete. It examines how the combined challenges of progressive collapse and blast loading influence the overall structural response …

Numerical Study On Enhancing The Geotechnical Behavior Of Strip Footings On Oil-Contaminated Sand Using Stone Columns, Ahmad Nasr, Waseim Azzam, Mohamed Ahmed Mahmoud Abdelrehem

Journal of Engineering Research

Ground improvement techniques are frequently employed in construction sites characterized by weak soil conditions that may result in suboptimal performance. The use of ordinary and encased stone columns aims to enhance endurance, shear strength, and soil hardness, thereby mitigating settlement issues and expediting the consolidation of contaminated sand soils. In this research, a comprehensive investigation involving 74 cases was conducted to assess the behavior of both ordinary stone columns and encased stone columns under strip footing in contaminated sand subgrade. The objective was to discern the impact and characteristics of encapsulation in comparison to encapsulated stone columns, employing a Finite …

Experimental Investigation Of Light-Weight Concrete-Filled Stainless Steel Tube Composite Long Columns, Nadia Fath Alla, Kamel Kandeel, Mahmoud El-Nagar

Journal of Engineering Research

The main target of this study is to investigate the behavior and performance of long composite circular stainless steel columns filled with light-weight concrete. An experimental study was carried out on four specimens, two of them are long composite circular stainless steel columns with length 1400 mm, diameter 100 mm and thickness of stainless steel tube 2 mm filled with light-weight and normal concrete with strengths 12 and 26 mpa respectively, which denoted by C1400/12 and C1400/26. The other two specimens are short composite circular stainless steel columns with length 500 mm, diameter 100 mm and thickness of stainless steel …

Effect Of Addition Monofilament And Multifilament Polypropylene Fibers On Mechanical Properties Of Concrete At Elevated Temperatures, Nourhan Osama Hanafy Dr

Journal of Engineering Research

Some researchers studied the effect of different types of fibers on the strengths of concrete at elevated temperature. However, there are some limitations in the study of the strengths of concrete using different methods of cooling after elevated temperature. Thus, the main objective of this research is to study the mechanical properties of concrete with the addition of 1% polypropylene fibers, featuring different structures, at elevated temperatures and with various cooling methods, compared to normal concrete. An experimental program using three different series of mixes, the first series included normal concrete (control) mix without fibers, the second series included 1% …

A Review Of Geopolymer Binder As A Grouting Material, Karla Sierra, Jinwoo An, Ryan Shamet, Jiannan Chen, Yong Je Kim, Boo Hyun Nam, Philip Park

Civil Engineering Faculty Publications

The utilization of geopolymer as a grouting material has gained significant attention in research and construction applications. Geopolymer grout is a type of binding material that differs from traditional grouts, typically based on Portland cement. Researchers have explored its effectiveness and potential applications in grouting processes, considering its unique properties and characteristics. In this paper, various studies employing and utilizing geopolymer as a grouting material are reviewed. The emphasis is on mixture design of geopolymer grout, physical property, chemical composition of geopolymer grout, rheological behavior of geopolymer grout such as yield stress (in case of Bingham fluid) and viscosity, and …

Evaluation Of Bridge Deterioration Factors: From Design Parameters To Community Impact., Lawrencia Akuffo

Theses and Dissertations

The structural health and economic variables influencing the state of bridges in New Jersey are thoroughly examined in this thesis. The predictive modeling of bridge conditions using stepwise selection and linear logistic regression approaches is the primary focus of the opening chapter. With its precise predictions about bridge condition, either being fair/good, our model offers insightful information about resource allocation and maintenance by identifying bridge features which affect the deterioration of bridges the most. This gives effective infrastructure management, which not only relies on the identification of the important predictors and their effects on bridge conditions but also ranks them …