Civil Engineering Commons^™

The Stability Of Nanobubbles And Its Application In Contaminated Sediment Treatment, Shaini Dilsha Aluthgun Hewage

Dissertations

This dissertation consists of two sections. First, nanobubbles' stability and behavior are studied using experimental and theoretical approaches. Second, nanobubbles application combined with ultrasound to remediate contaminated sediments is discussed.

The stability study consists of four sections. (i). Laboratory investigation to determine bubble size distributions and zeta potentials for different gases, pH levels, temperatures, and salt conditions. (ii). A theoretical study based on the diffused double layer theory to explain nanobubbles' behavior in different NaCl concentrations. (iii). Nanobubbles' stability in electrolyte solutions under different ion valencies using deionized water, NaCl, Na₂SO₄, Na₃PO₄, …

The Compressive And Flexural Strength Of Concrete Containing Recycled Waste Plastic, Isaiah Akinkunmi

Master of Science in Civil Engineering Theses

Annually, tons of plastic wastes end up in landfills and the oceans through indiscriminate dumping, constituting a major source of pollution to the environment and threat to human health and marine lives. It therefore necessitates an innovative strategy to help mitigate the environmental hazards caused by this pollution. A feasible eco-friendly strategy is by using granulated plastics, fibers or regrinds in concreting. This research explored the feasibility of this strategy by testing the compressive and flexural strengths of hardened concrete specimens containing varying percent of plastic aggregates used as partial replacement for fine aggregates. The compressive strength of specimens of …

An Experimental Investigation Of Alternative Wave Attenuation Mechanisms For A Modular Breakwater, Richard Perry

Electronic Theses and Dissertations

Global warming and sea level rise threaten to render traditional coastal protection structures as less effective. Floating breakwaters offer the advantages of adapting to rising sea level, allowing important material transport to occur, and being able to deploy and adapt to varying environmental conditions (seabed, depth, etc.). Traditional floating breakwaters typically consist of reflective concrete structures that are limited semi-sheltered locations. This research aimed to construct floating breakwaters out of lightweight materials with a smaller footprint while utilizing alternative attenuation mechanisms. Three breakwaters consisting of a box, beach, and pipe designs were constructed at 1:40 scale and tested in a …

Effects Of City Growth On Tall Building Cladding Fatigue, Hang You

Electronic Thesis and Dissertation Repository

As city develops there will be changes in the aerodynamic characteristics due to varying building surrounding and topology. For example, the city growth around a tall building can cause an increase in wind load due to venturi or wake effects or decrease due to sheltering effects depending on the type of surrounding. The densification of cities will also increase the turbulence level due to wake effects. In the present study, the implication of these changes on the aerodynamic forces on cladding connections is investigated. With increased fluctuations in the wind loads, the cladding connections will also experience stress fluctuations, which …

Investigating The Role Of Iron In The Photogranulation Phenomenon, Abeera Ayaz Ansari

Doctoral Dissertations

Oxygenic photogranules (OPGs) are dense spherical microbial aggregates that are used for self-aerating wastewater treatment. Filamentous cyanobacteria are key granulating species, providing structural backbone and integrity in OPGs. Currently, the mechanisms for selecting filamentous cyanobacteria and their ability to form spherical OPGs are not well understood. Literature shows that iron (Fe) availability plays a significant role in the cyanobacterial growth and colony formation. Moreover, Fe availability is known to be dependent upon light, which is an essential growth substrate for the phototrophs. This research has investigated the role of Fe in the photogranulation phenomenon and the impact of light intensity …

Feasibility Of Geothermal Energy Piles In New Orleans Alluvial Soils, Patrick A. Thurmond

University of New Orleans Theses and Dissertations

Geothermal energy piles offer the benefits of modifying existing construction practices to reduce costs associated with heating and cooling. A major obstacle today in effective utilization of these systems is a general lack of site-specific data on the thermal properties of subsoils. To maximize the potential efficiency of these systems, engineers require an understanding of the potential impact of this technology on existing foundation design methodology as well as a means for quantifying potential heat transfer through soil by determination of the soil’s thermal conductivity. This study examines the feasibility of energy piles with a focus on alluvial soils found …

Geo-Structural Analysis Of Integral Abutment Bridges, Biyi Li

Electronic Thesis and Dissertation Repository

Integral abutment bridges are jointless bridges where bridge decks and girders are integrated with abutments. The longitudinal displacements and rotations of the bridge are partially accommodated by the soil-pile system wherein the soil surrounding the piles generates active and reactive lateral forces when the piles deflect due to the movement of the superstructure. Since the soil stress-strain responses are inherently nonlinear, the pile deflection and the soil stiffness are interdependent. Consequently, evaluating soil-pile interactions requires a detailed geo-structural analysis. There are two common approaches used to idealize the soil-pile interactions for laterally loaded piles: the p-y and continuum mechanics approaches …

Reliability-Based Calibration Of Design Wind Load, Snow Load And Companion Load Factors Considering Climate Change Effect, Qian Tang

Electronic Thesis and Dissertation Repository

Wind load and snow load are two of the environmental loads that need to be considered for structural design. This study compared the statistical characteristics of the annual maximum thunderstorm and non-thunderstorm winds based on the updated wind speed dataset and carried out the extreme value analysis for wind load by treating the synoptic and thunderstorm winds separately. The results indicated that for southern Ontario and the southern part of the Prairies, the extreme winds could be dominated by thunderstorm winds. The consideration of both thunderstorm winds and synoptic winds separately to recommend the reference wind velocity pressure for the …

Finite Element Analyses And Random Field Modeling Of Naturally Corroded Underground Energy Pipelines, Ji Bao

Electronic Thesis and Dissertation Repository

Metal-loss corrosion is one of the major threats to the integrity of oil and natural gas pipelines. The Fitness-For-Service (FFS) assessment is commonly carried out to demonstrate the integrity of the corroded pipelines. The naturally occurring corrosions on the external surfaces are irregularly shaped three-dimensional features. Due to the geometric complexity of the natural corrosion features, the research of FFS assessment in the previous studies always employed the pipe segments containing artificially induced corrosion features. However, since artificial features are in general regular-shaped, e.g. cubic or semi-ellipsoidal, they do not capture geometric characteristics of naturally occurring corrosions. The thesis develops …

Laboratory Testing And Mechanistic Analysis Of Treated Subgrade Soils, Hari Kumar Reddy Yarrapureddi

Civil Engineering Theses

Calcium-based stabilizing agents such as cement and lime have been extensively used to improve the engineering properties of base and subgrade layers of pavement systems. Recently, polymers and chemical stabilizers have become popular due to cost efficiency, ease of application, and fast curing times. In this study, California Bearing Ratio (CBR) values of polymer and chemical treated soils were compared with the CBR values of soils treated with conventional stabilizers. Parametric sensitivity analyses was carried out on key parameters including the type of subgrade soil, stabilizing agent, stabilizing agent treatment levels, and moisture conditioning. Additionally, numerical analyses was performed to …

Expanding The Concept Of Comprehensive Area Ratio Parameter To The South-Central States Towards Simplifying The Structural Evaluation Of Flexible Pavements At The Network Level, Nitish R. Bastola

Civil Engineering Theses

The surface deflection bowl data collected through Non-Destructive Testing (NDT) has been widely utilized by various Department of Transportation (DOTs) in the South-Central States and other places. The primary purpose of using deflection-based NDTs in network-level assessment is to identify a weak pavement section that requires further analysis at the project level. The falling weight deflectometer (FWD) test is one of the common NDT based tests utilized by highway agencies in assessing the performance of the flexible pavement. However, a robust method to evaluate pavement sections utilizing FWD data from all the sensors are seldom developed. There is always a …

Housing Pre-Fabrication And Resource Optimization, Emma Dubensky

Honors Theses

Enclosure during construction is often time-consuming, expensive, and at the mercy of the weather. By introducing methods for manufacturing prefabricated enclosure components such as wall panels and roof sections, the impact of the three major variables is reduced. Designs for trusses, roof sections, wall sections, and foundations were developed and selected using civil engineering principles; and manufacturing and logistical processes were optimized using engineering and project management skill sets. These multi-disciplinary efforts were combined to create an accessible and versatile set of designs and instructions that can improve the effectiveness of both a skilled and non-skilled volunteer workforce. By creating …

Housing Prefabrication And Resource Optimization, Megan Scherpereel

Honors Theses

Enclosure during construction is often time-consuming, expensive, and at the mercy of the weather. By introducing methods for manufacturing prefabricated enclosure components such as wall panels and roof sections, the impact of the three major variables is reduced. Designs for trusses, roof sections, wall sections, and foundations were developed and selected using civil engineering principles; and manufacturing and logistical processes were optimized using engineering and project management skill sets. These multi-disciplinary efforts were combined to create an accessible and versatile set of designs and instructions that can improve the effectiveness of both a skilled and non-skilled volunteer workforce. By creating …

3d Study Of Gas Hydrate Formation And Dissociation In Porous Media And Dem Modeling Of Granular Materials, Zaher Jarrar

Doctoral Dissertations

Natural methane gas hydrates availability and ongoing rise in demand for energy, motivated researchers to consider gas hydrates as a potential energy source. Production of methane from hydrate-bearing sediments requires hydrate dissociation for releasing mobile methane gas in sediments prior to gas production operations. Fines may migrate through or clog the pore space of sandy sediments depending on the geometry and topology of the pore space. This dissertation employs unique in situ experiments and techniques to gain a comprehensive understanding of the associated physical processes (such as fines migration, clogging and gas driven fracture) and validation of hydrate dissociation models’ …

Behavior Of Concrete Structures Reinforced With High Strength Steel, Rahman S. Kareem

Graduate Theses and Dissertations

The structural strength and corrosion resistance of concrete members are improved when A1035 steel is used as the main reinforcement. The enhancement of A1035 is achieved by the modification of the composition and microstructure of the steel. Therefore, the behavior of concrete structures reinforced with high-performance steel (A1035) is different from those reinforced with the regular steel (A615). Concrete bridge decks reinforced with different amounts of A1035 were studied in this research program. The structural behavior of twelve concrete bridge decks reinforced with A615 Grade 420 (60 ksi) and A1035 Grade 830 (120 ksi) steel was investigated at both service …

A Methodological Framework To Evaluate Community Perceptions Of Economic And Safety Impacts Attributed To Highway Bypass And Widening Projects, Karla Diaz-Corro

Graduate Theses and Dissertations

Transportation practitioners have proposed the construction of highway bypass and widening projects in rural communities to address traffic-related problems that include noise pollution and congestion, among others. In the past, the construction of bypass projects has led community residents to raise concerns about potential decreases in business activity for businesses located along the bypassed road. For transportation organizations, it is essential to understand the economic, social, and safety impacts of transportation projects in terms of public perceptions as public input is a required part of the project planning phase. Moreover, it is recommended that agencies perform retrospective analyses of project …

Moisture Monitoring Of A Clt Structure In A Southern Climate, Elizabeth Poblete

Graduate Theses and Dissertations

Understanding of moisture behavior in cross laminated timber (CLT) is critical to the widespread use of CLT in construction in the United States. Currently, very little data exists on the long-term impact of moisture on CLT. The objective of this research is to collect data regarding the long-term moisture variation in the CLT panel at the University of Arkansas Adohi Hall residence hall. The climate of Northwest Arkansas is different from previously monitored buildings, as they were in the Pacific Northwest. Comparatively, Northwest Arkansas has a warmer climate with higher average annual precipitation. Waterproofing efforts are usually employed to prevent …

Cement Stabilized Crushed Stone Base Course Strength And Stiffness Analysis, Andrew Deschenes

Graduate Theses and Dissertations

Approximately 70 – 80% of state departments of transportations (DOTs) utilize the 1993 AASTHO Guide for Design of Pavement Structures (1993 AASHTO) [1] for structural design of pavements. A growing portion of DOT’s are beginning to implement the Mechanistic-Empirical Pavement Design Guide (MEPDG), referred to as AASHTOWare Pavement ME [2]. The 1993 AASHTO flexible guide applies empirically derived unitless strength values referred to as structural layer coefficients and structural numbers (SN) to pavement thickness and pavement types. The 1993 AASHTO rigid flexible guide utilizes the depth and strength of the concrete pavement, with the composite spring constant (kc), which is …

An Investigation Into The Effects Of Fly Ash On Freeze-Thaw Durability Prediction, Yancy Schrader

Graduate Theses and Dissertations

Air is purposefully entrained into concrete primarily to improve resistance to freeze-thaw deterioration while saturated with water. Air entraining admixtures (AEAs) are chemical admixtures designed to entrain air into the concrete to provide adequate resistance to the effects of freezing and thawing. One of the challenges associated with air entrainment in concrete is the interaction of an AEA with supplementary cementitious materials present in the concrete, particularly fly ash. Fly ash is a by-product of the coal fired electrical generation industry, and often contains residual unburned carbon and other components that can increase the AEA demand of a particular concrete …

Effect Of Citric Acid On Slump, Compressive Strength, And Setting Time Of Belitic Calcium Sulfoaluminate Concrete, Israel Aguilar Rosero

Graduate Theses and Dissertations

Belitic calcium sulfoaluminate (BCSA) cement has well established advantages related to fast setting time, fast strength gain, long-term strengths, shrinkage, and sustainability. Due to its fast setting and hardening, this type of cement has historically been used to repair concrete structures, highways, and runways. This work provides much needed guidance on establishing mix design criteria for BCSA cement. Guidance is also given on the effects of set retarders on strength, slump, and setting times. Citric acid and a phosphonic acid-based admixture were tested as retarders for different concrete mixtures. Three studies were performed. In the slump study five different water …

Using Bcsa Cement To Repair Waterway Transportation Structures, Anazaria Johanis Ortega Gonzalez

Graduate Theses and Dissertations

Many maritime structures (e.g., locks, dams, ports) in the US are either reaching or are past their design lives, and there are limited funds for the necessary maintenance activities which can lead to repairs that requires closures. These structures are not easy to detour and often require dewatering before repairs can be made, closures can cause delays and business-related losses which can have a large effect on the nation’s economy. Thus, it is advantageous to reduce the repair time for maritime structures. BCSA (belitic calcium sulfoaluminate) cement is a promising material to perform this type of repair due to its …

Seismic Loading Effects Within Orthogonally Connected Steel Lateral Force Resisting Systems, Alhussin Faraj Aliwan

Graduate Theses and Dissertations

Steel buildings located within seismically active regions require special design considerations to ensure public safety and prevent collapse during an extreme seismic event. Two commonly used steel systems are special moment frames (SMFs) and buckling-restrained braced frames (BRBFs). When two seismic systems share a common column in an orthogonal configuration (such as at a building corner), design specifications currently consider a 100+30 rule wherein the shared column is designed for 100% fuse demand in one direction, plus 30% fuse demand from the other direction. While this rule has been shown to be reasonable for elastic building response, a few studies …

Leveraging Biomimicry And Additive Manufacturing To Improve Load Transfer In Brittle Materials, Ana Paula Bernardo

Graduate Theses and Dissertations

With the emergence of Additive Manufacturing (i.e., 3D printing) in construction, new strategically designed shapes can be created to improve load transfer through structural members and foundations. Cross-sections can be optimized to carry load using less material, or even using weaker constituent materials, like soils, which are cheap and abundant. The goal of this research is to investigate the benefits of using cellular patterns which leverage biomimicry in civil engineering applications, since nature has perfectly engineered materials and patterns which carry loads with the least amount of material possible. Most of the periodic cellular work to date has focused on …

Sustainability In Construction: Using Lean Management Principles To Reduce Waste, Matthew Waite

Theses and Dissertations

The construction industry is facing many challenges. There are growing consumer demands for sustainable building. The construction industry generates a significant portion of the waste going into landfills. The construction industry has failed to keep pace with productivity in the manufacturing industry. Through adoption of Lean management principles, the construction industry can become more sustainable while increasing productivity. The literature was evaluated for three concepts: Lean management principles interaction with sustainability, the current state of sustainability in the construction industry, and the current state of Lean management principles in the construction industry. Lean management philosophies interactions with sustainability has been …

Investigating The Compactability Of Hot Mix Asphalt Utilizing The Concept Of The Locking Point, Pawel Andrzej Polaczyk

Doctoral Dissertations

Compaction is an important process for the asphalt mixture service life. An adequately compacted mixture is crucial for long-lasting pavement. Compaction is a procedure utilized to compress and decrease the volume of the material, which provides essential ingredients that influence the pavement's performance. During asphalt mix compaction, the aggregate coated with asphalt binder are compressed together, following an increase of interparticle friction and surface contact and finally interlocking to provide the resistance to deformation. At the same time, the permeability is decreased, and the durability is increased. Compactability is utilized to evaluate how much compaction energy is required to compact …

Comparison Of Additively Manufactured And Wrought 17-4 Ph Stainless Steels In Ultra Low Cycle Fatigue, Timothy Strasser

Graduate Theses and Dissertations

Additive manufacturing (AM) processes allow for creation of complex geometries that are otherwise impractical to fabricate with traditional subtractive methods. AM technology has potential to improve the optimization of seismic lateral force resisting components which dissipate seismic energy through large plastic strains; however, the ultra low-cycle fatigue performance of AM metals are not yet well understood. Void formation during the AM fabrication process has potential to affect performance. This study compares the performance of heat-treated and non-heat-treated AM and wrought 17-4PH stainless steel in Ultra Low Cycle Fatigue. To understand ULCF performance differences between the AM and wrought specimens, post …

Exploring The Variability In The Gray Scale Imaging Process Of Asphalt Samples, David Oluwawade Olatunji

Civil Engineering Undergraduate Honors Theses

Gray scale image analysis is a powerful tool for testing asphalt concrete materials. From material composition to surface properties, gray scale analysis has shown evidence as a non-invasive way to obtain information from asphalt samples. Casillas et al. used a gray scale analysis to measure the Representative Volume Element of three asphalt sample geometries to understand the minimum size at which an asphalt sample is representative of a larger homogeneous mixture [1]. While the gray scale analysis used in this experiment yielded results, there were unknown factors in the image capturing process. Particularly, not much was known about the effect …

Impacts Of Environmental And Hydrologic Factors On Urban Stream Water Quality., Jason Patrik Ingram

Electronic Theses and Dissertations

Urban streams can be impacted by a multitude of hydrologic and environmental factors, making maintaining these water sources difficult. Urbanization can exacerbate these impacts creating new challenges in preserving suitable urban stream water quality. Urbanization is the development of city landscape and suburban living within an otherwise natural region. For this environmental impact study, the effects of city development on urban stream water quality was monitored for Mill Creek in Louisville, Kentucky. To study the effects of urbanization on Mill Creek, this project was completed utilizing the BACI method for comparing impacts. The results of the water quality monitoring were …

Understanding Mesoscopic Chemo-Mechanical Distress And Mitigation Mechanisms Of Concrete Subject To Asr, Md Asif Rahman

Boise State University Theses and Dissertations

Alkali-silica reaction (ASR) is one of the common sources of concrete damage worldwide. The surrounding environment, namely, temperature and humidity greatly influence the alkali-silica reaction induced expansion. Global warming (GW) has caused frequent change in the climate and initiated extreme weather events in recent years. These extreme events anticipate random change in temperature and humidity, and convey potential threats to the concrete infrastructure. Moreover, external loading conditions also affect the service life of concrete. Thus, complex mechanisms of ASR under the impact of seasonal change and global warming require a precise quantitative assessment to guide the durable infrastructure materials design …

Development And Application Of Sustainable Binders Comprising Of Fly Ash And Ground Glass Fibers In Portland Cement And Geopolymer Concrete, Omar Alsanusi Amer

All Dissertations

Since cement production is responsible for a significant share of anthropogenic CO2 emissions, the sustainability of concrete construction has become one of the most targeted research and construction industry goals. Many suggestions have been in use to encourage sustainability of concrete construction; one such approach is to partially replace cement by industrial byproducts. The most known industrial byproduct used in concrete construction worldwide has been fly ash, which is a byproduct of burning coal for power generation.

Fly ash use in concrete has various benefits. It reduces the water demand, reduces plastic shrinkage, reduces permeability, and thus improving the durability …