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2020

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Articles 331 - 360 of 571

Full-Text Articles in Civil Engineering

Experimental And Numerical Study Of Steel Fiber Reinforced Concrete Structures Subjected To Internal Explosion, Nikhil Vasant Moon May 2020

Experimental And Numerical Study Of Steel Fiber Reinforced Concrete Structures Subjected To Internal Explosion, Nikhil Vasant Moon

Civil Engineering Theses - Archive

This research investigates the effect of an accidental explosion of a steam boiler in a boiler room on steel fiber reinforced concrete (SFRC) structure in an industrial facility, using nonlinear analysis in ABAQUS FEA software. The mechanical properties of SFRC are calculated through testing at the UTA Civil Engineering Laboratory Building. Steel fiber dosages in concrete at different volume fractions are examined for the mechanical properties of concrete. In total, 9 (4” x 8”) cylindrical specimens for compressive strength and modulus of elasticity test, 9 (4” x 8”) cylindrical specimens for tensile strength test, and 9 (6” x 6” x …


Designing Technology For Different Scales Of Irrigation Scheduling, Paolo Alexander Consalvo May 2020

Designing Technology For Different Scales Of Irrigation Scheduling, Paolo Alexander Consalvo

Undergraduate Honors Capstone Projects

Uncertainty in water availability is a significant challenge to the agriculture industry. Farmers and irrigators depend on novel uses of sensors and data to maximize water efficiency. Documented studies have demonstrated scheduling irrigation is a straightforward, deterministic means of achieving water efficiency. Irrigation scheduling uses several parameters to determine the moment of crop water stress due to available water in the soil. However, sensors and data for soil moisture and matric potential, a parameter describing water available to plants, have the potential to train machine learning algorithms to forecast water irrigation needs based on previous measurements. Satellite remote-sensing is another …


Promoting The Sustainable Utilization Of Groundwater Resources In Ethiopia Using The Integrated Groundwater Footprint Index, Xinyu Lin May 2020

Promoting The Sustainable Utilization Of Groundwater Resources In Ethiopia Using The Integrated Groundwater Footprint Index, Xinyu Lin

Honors Scholar Theses

The country of Ethiopia is highly vulnerable to human-caused climate change and is already suffering from the effects. The predominately rural population relies heavily on small-scale agriculture, with 78% of households having at least one member engaged in the field, yet staple crops are highly susceptible to droughts and other weather shocks. Total and agricultural GDP growth in the country have been strongly linked to inter-annual rainfall variability, of which Ethiopia has among the highest in sub-Saharan Africa. A decrease in rainfall since the 1970s has been one of the primary causes of low crop yields, and stresses the immediate …


Nitrate And Herbicides Removal From Groundwater Using Immobilized Algae, Sara Mollamohammada May 2020

Nitrate And Herbicides Removal From Groundwater Using Immobilized Algae, Sara Mollamohammada

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

To improve crop yield and control broadleaf weeds, many farmers apply nitrate-based fertilizers and chemical herbicides to their fields. Excessive use of these chemicals can cause contamination in waterbodies and impact on the public health. The physical and chemical methods have been suggested to remove these herbicides are usually costly. In this study, the capability of immobilized algal beads in removing nitrate and several herbicides of environmental concern from synthetic and actual groundwater and surface water was evaluated.

The experiments were performed in batch, sequencing batch and continuous flow modes and the effect of different operational conditions (light intensity, cultivation …


Examining Current State Of Practice Of Enhancing Visibility Of Winter Operations Vehicles, Wasiq Ameen May 2020

Examining Current State Of Practice Of Enhancing Visibility Of Winter Operations Vehicles, Wasiq Ameen

Civil Engineering Theses - Archive

Despite precautions taken by the operators of maintenance vehicles, insufficient visibility of winter operations vehicles cause many collisions in the United States. Numerous methods have been developed to enhance the visibility of winter operations vehicles. Although the visibility of winter operations vehicles has enhanced through these methods, the consistency in the implementation of the methods for enhancing their visibility is critical to avoid collisions. The inconsistencies in the implementation of the methods confuse the public who are traveling in winter conditions when visibility is low. The confusion leads to a delay in perception time and response time of the drivers …


Toward A Seismic Resistant Steel Staggered Truss Framing System (Stf), Ra'ed Al-Mazaidh May 2020

Toward A Seismic Resistant Steel Staggered Truss Framing System (Stf), Ra'ed Al-Mazaidh

Civil Engineering Dissertations - Archive

The Staggered Truss Framing (STF) system is a type of steel structural system used in mid- to high-rise buildings. It was initially developed in the 1960s in order to create a steel framing system that has low floor-to-floor height (9 to 10 ft.) and wide column-free space (60 to 80 ft.). This system consists of a series of story-high trusses spanning the total width between two rows of exterior columns and arranged in a staggered pattern on adjacent column lines. Due to the staggered layout, lateral seismic force transfer in the STF system is also in a staggered manner from …


Multiaxial Fatigue Of Notched Steel Plates And Investigation Of Cfrp Retrofits For Crack Initiation Prevention, Ayumi Fujii May 2020

Multiaxial Fatigue Of Notched Steel Plates And Investigation Of Cfrp Retrofits For Crack Initiation Prevention, Ayumi Fujii

Civil Engineering Undergraduate Honors Theses

Fatigue cracks are cracks that result from repeated loading over time, often following millions of loading cycles. Fatigue cracks occur even if the applied load is not large enough to cause material yield. Once a fatigue crack initiates, resulting stress concentrations at the crack tip often make it difficult to arrest the growth of the crack. In order to prevent growth and propagation of fatigue cracks within structural components, it is necessary to alter the stress condition at the crack tip. Fatigue cracks in steel structures resulting from multiaxial loading and or geometry conditions that result in complex states of …


Soil Moisture Content Determination By Means Of The Electromagnetic Spectrum, Julia Loshelder May 2020

Soil Moisture Content Determination By Means Of The Electromagnetic Spectrum, Julia Loshelder

Civil Engineering Undergraduate Honors Theses

Soil moisture content provides information about the strength, permeability, and compressibility of the soil under investigation. In the research described herein, the relationship between moisture content and reflectance values obtained from spectroscopy was developed to investigate whether in-situ moisture content can be determined in a faster and more efficient way than the current methods. The soil under investigation was laboratory-compacted kaolinite clay mixed with pyranine dye. These specimens were placed beneath an ultraviolet light and a halogen illuminator where reflectance values were collected over a 24-hour period. Correlations were developed from the following methods: 1) spectral indices, 2) continuum analyses …


Understanding Workability In Belitic Calcium Sulfoaluminate Concrete Mixtures, Caleb W. Chesnut May 2020

Understanding Workability In Belitic Calcium Sulfoaluminate Concrete Mixtures, Caleb W. Chesnut

Civil Engineering Undergraduate Honors Theses

Belitic Calcium Sulfoaluminate cement (BCSA) is an emerging technology in the concrete industry. BCSA has similar hardened properties to portland cement (PC) but can set in under 20 minutes and reach 4,000 psi in less than 2 hours. Portland cement accounts for 8% of the world’s CO2 emissions, BCSA cements require less energy to produce. Studies have shown that 40% less CO2 is emitted during the production of BCSA cement than portland cement. This environmental benefit also makes it a very promising PC alternative. Before a new material can be used, designers need to understand the material’s properties. The goal …


Countermeasures For Pedestrian-Involved Accidents On Interstate-Highways, Anna C. Hunter May 2020

Countermeasures For Pedestrian-Involved Accidents On Interstate-Highways, Anna C. Hunter

Civil Engineering Undergraduate Honors Theses

Pedestrian access to the Interstate is prohibited, but many pedestrian-involved accidents still occur on the Interstate in the United States. This project is a case study of West Memphis, Arkansas, which has the second highest occurrence of pedestrian-involved accidents on the Interstate in Arkansas. The study site location includes a segment of Interstate I-40 which is at- grade. The surrounding area contains several different land-uses, which is believed to be the primary generator of these accidents. The goal of this project is to determine the primary causes of these accidents and determine potential countermeasures to reduce the crash rate for …


Applying Performance Engineered Mixture Design To Permeable Concrete, Rachel Pohl May 2020

Applying Performance Engineered Mixture Design To Permeable Concrete, Rachel Pohl

Civil Engineering Undergraduate Honors Theses

The scope of research and application related to permeable pavements has recently broadened. The desire to significantly reduce the environmental impact of large paved areas makes the permeable pavement concept more desirable (American Concrete Institute, 2018). Although research and interest are increasing, the actual application of permeable pavement is still very limited and has not reached the airfield arena. In airfields, permeable pavement could possibly be used for aircraft aprons - which currently require substantial measures to control stormwater runoff. Permeable pavements are typically used in low-traffic-volume / lightly loaded applications; questions remain regarding a permeable pavement’s ability to hold …


Estimation Of Interior And Contents Damage Due To Wind Driven Rain Ingress Into Mid/High-Rise Buildings, Zhuoxuan Wei May 2020

Estimation Of Interior And Contents Damage Due To Wind Driven Rain Ingress Into Mid/High-Rise Buildings, Zhuoxuan Wei

Theses and Dissertations

Hurricanes can lead to the loss of millions of dollars and the death of hundreds of people. The increasing concentration of people in coastal cities, exacerbates this problem and results in greater hurricane damage to residential buildings. In particular, recent hurricanes in Florida have shown the vulnerability of mid/high-rise buildings (MHRB) to hurricane-induced water ingress. However, few damage models are able to produce realistic estimates of interior damage. To accurately estimate the interior and contents damage of mid/high-rise buildings due to water ingress during hurricanes, this thesis proposes a new physics-based methodology, which extends the results of previous work on …


Development Of Plane Rotating Traction System: Based On The High-Speed Rail (72+128+72) M Continuous Prestressed Concrete Beam Bridge, Weinan Wang May 2020

Development Of Plane Rotating Traction System: Based On The High-Speed Rail (72+128+72) M Continuous Prestressed Concrete Beam Bridge, Weinan Wang

Theses and Dissertations

With the advent of rotate construction techniques, it is easy to build a new bridge crossing over existing structures, rivers and valleys quickly, easily and safely. Although the general concept of the rotating method is similar for different engineering characteristics, it is necessary to make some changes, which are more in line with the requirements of the particular project. Based on a 3-spans (72+128+72)m continuous concrete bridge, this paper presents a new rotation method, the down-slide-way unbalanced rotation system, which can save time and reduce cost compared to the up-slide-way rotation method. Through the improvements of the traction system and …


Riveted Steel Railway Bridge Health Monitoring And Damage Detection, Ahmed Rageh May 2020

Riveted Steel Railway Bridge Health Monitoring And Damage Detection, Ahmed Rageh

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

Visual inspection is often used to assess the condition of railway bridges at discrete points in time, an approach that can be subjective and possibly unsafe. Alternatively, certain bridges have their condition assessed via the installation of a large number of sensors. These sensors can be costly to place, power and maintain. Therefore, reducing their numbers and maximizing the extracted information is of utmost importance. In addition, evaluating bridge condition from measured response can be quite challenging due to loading and environmental variations, especially when a limited number of sensors are used.

The focus of this research is to develop …


A Hybrid Experimental-Numerical Study On The Flow Topology In The Confluence Hydrodynamics Zone Of An Open Channel With Lateral Drainage Pipe Discharge, Mohammad Nazari-Sharabian May 2020

A Hybrid Experimental-Numerical Study On The Flow Topology In The Confluence Hydrodynamics Zone Of An Open Channel With Lateral Drainage Pipe Discharge, Mohammad Nazari-Sharabian

UNLV Theses, Dissertations, Professional Papers, and Capstones

To avoid disrupting the flow in flood control channels with lateral drainage pipes, or impact channel capacity, confluences are constructed at small angles (Maximum 30○). These small angles are costly to construct, since they require more real estate than greater angles.

By performing several laboratory experiments in the Fluid Dynamics Laboratory of the University of Nevada, Las Vegas (UNLV) and utilizing a numerical model (FLOW-3D), this study investigated the impact of submerged lateral drainage pipe discharges into rectangular open channels, on flow topology in the confluence hydrodynamics zone (CHZ). This was done across a range of channel widths, flow rates, …


Acoustic Sonolysis Of Antibiotics In Water, Natalie Pinon May 2020

Acoustic Sonolysis Of Antibiotics In Water, Natalie Pinon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Antibiotic resistance is a prominent issue in the world today. It is said by the Centers for Disease Control and Prevention that it is one of the major public health challenges we face today. Predominantly, antibiotic resistance is growing because conventional wastewater treatment processes are not able to completely break down antibiotics. As bacteria are exposed to such antibiotics, which don’t kill them due to selective pressure, they become immune and develop resistance which is a huge health concern. To prevent this from occurring, antibiotics need to be removed from hospital wastewater. Sonication is a promising technology that can be …


Public-Private Partnership Contract Framework Development And Project Performance Analysis Compared To Design-Build In The Us Highway Projects, Medya Fathi May 2020

Public-Private Partnership Contract Framework Development And Project Performance Analysis Compared To Design-Build In The Us Highway Projects, Medya Fathi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Construction projects can be delivered through various approaches; nevertheless, all practitioners and involved parties have a mutual goal, which is completing the project within the original scope, defined budget, and schedule. Reviewing the literature on public-private partnership (PPP), many efforts have been made covering different research areas, including policies, risks, roles and responsibilities, and finance. However, a study involving the development of a framework for PPP contracts, and quantitative assessment of project performance associated with PPP highway projects in the US is lacking. Therefore, this research fills such a noticeable gap in the body of knowledge on the PPP delivery …


An Evaluation Of Bank Storage At Lake Mead Reservoir In The Southwest United States, Jon Woodrow Wilson May 2020

An Evaluation Of Bank Storage At Lake Mead Reservoir In The Southwest United States, Jon Woodrow Wilson

UNLV Theses, Dissertations, Professional Papers, and Capstones

A water balance model is employed at Lake Mead to monitor and verify changing hydrology that affects total volume at the reservoir. Bank storage, which is defined as the volume of water captured in permeable lithologic layers subject to changes induced by contact and proximity to an open waterbody, is one component that is updated regularly and is based upon data and methods that were developed in the 1960’s from observations made within the first 30 years of the reservoir's maturation. Since this period, the reservoir has undergone further development and a current understanding of additional hydrologic affects to bank …


Bs News May/June May 2020

Bs News May/June

Building Services Engineering

No abstract provided.


Quantitative Resistance Assessment Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon Apr 2020

Quantitative Resistance Assessment Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The blast resistance of a typical reinforced concrete bridge pier column design was modeled with a nonlinear finite element approach that considers material damage, fracture, and separation. While varying concrete strength, amount of longitudinal reinforcing steel, and gravity load, the effect of applying an externally bonded steel fiber reinforced polymer (SFRP) wrapping was assessed. The presented approach uniquely quantifies column blast resistance in terms of charge weight. It was found that blast capacity was roughly linearly related to concrete strength and steel reinforcement ratio, the former of which is most influential. It was further found that a single layer of …


Load Truncation Approach For Development Of Live Load Factors For Bridge Rating, Sasan Siavashi, Christopher D. Eamon Apr 2020

Load Truncation Approach For Development Of Live Load Factors For Bridge Rating, Sasan Siavashi, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

Various local governments have developed state-specific vehicular live load factors for bridge rating. However, a significant computational demand is often associated with such an effort. This is due to the large size of the weigh-in-motion (WIM) databases frequently used in the procedure. In this study, a method is proposed that can significantly reduce the computational cost of the analysis, while still maintaining reasonable accuracy. The proposed approach develops approximate live load random variable statistics by truncating the WIM database based on gross vehicle weight, then a complete reliability analysis is conducted to develop new live load factors that meet AASHTO-specified …


Reliability-Calibrated Ann-Based Load And Resistance Factor Load Rating For Steel Girder Bridges, Francisco Garcia Apr 2020

Reliability-Calibrated Ann-Based Load And Resistance Factor Load Rating For Steel Girder Bridges, Francisco Garcia

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

This research aimed to develop a supplemental ANN-based tool to support the Nebraska Department of Transportation (NDOT) in optimizing bridge management investments when choosing between refined modeling, field testing, retrofitting, or bridge replacement. ANNs require an initial investment to collect data and train a network, but offer future benefits of speed and accessibility to engineers utilizing the trained ANN in the future. As the population of rural bridges in the Midwest approaching the end of their design service lives increases, Departments of Transportation are under mounting pressure to balance safety of the traveling public with fiscal constraints. While it is …


Decision-Support System For Lid Footprint Planning And Urban Runoff Mitigation In The Lower Rio Grande Valley Of South Texas, Javier Guerrero, Taufiqul Alam, Ahmed Mahmoud, Kim D. Jones, Andrew Ernest Apr 2020

Decision-Support System For Lid Footprint Planning And Urban Runoff Mitigation In The Lower Rio Grande Valley Of South Texas, Javier Guerrero, Taufiqul Alam, Ahmed Mahmoud, Kim D. Jones, Andrew Ernest

Civil Engineering Faculty Publications

To address regional flooding in the United States, federal and state agencies are adopting strict drainage policies in any large-scale commercial development within the watershed boundary. The conventional approach of implementing a wet detention pond (WP) reduces the land cover and causes operation and maintenance challenges eventually. The present study developed a decision-support system (DSS) in the Lower Rio Grande Valley region of South Texas for optimal selection of Best Management Practices (BMPs) by substituting a portion of the WP footprint with three regionally promising low-impact development practices, namely, porous concrete pavement (PCP), bioretention (BR), and bioswale (BS). Source Load …


The Siltcatcher: A Sediment-Capture System For Wetland Creation And Coastal Protection In Western Lake Pontchartrain, Andrew M. Wright Apr 2020

The Siltcatcher: A Sediment-Capture System For Wetland Creation And Coastal Protection In Western Lake Pontchartrain, Andrew M. Wright

LSU Master's Theses

The West Lake Pontchartrain region faces a number of long-term environmental challenges due to anthropogenic climate disturbance and landscape modification, including sea level rise, increased storm surge risk, shoreline erosion, and wetland degradation. In response, this thesis applies recent research in the fields of landscape architecture and civil engineering to propose a dynamic, natural-systems solution for wetland creation and shoreline protection. The project envisions a series of breakwater-like structures in western Lake Pontchartrain positioned to slow water released from the nearby Bonnet Carré Spillway, causing suspended sediment to settle and create self-building and self-sustaining wetlands capable of keeping pace with …


Physical And Biological Factors Controlling The Fate Of Nitrate In A Louisiana Coastal Deltaic Floodplain, Alexandra Christensen Apr 2020

Physical And Biological Factors Controlling The Fate Of Nitrate In A Louisiana Coastal Deltaic Floodplain, Alexandra Christensen

LSU Doctoral Dissertations

The Mississippi River Delta is threatened by a growing pressure to support large human populations in the United States both with food production, navigation systems, and urban development in the Mississippi River Basin. Nitrate-nitrogen load in the Mississippi River, up to 100 Tg N yr-1 from agricultural and urban runoff, leads to phytoplankton blooms and hypoxia across the Louisiana continental shelf, creating dead zones of low dissolved oxygen threatening a significant commercial fishery. Along the coast and river corridors, floodplain ecosystems have the capacity to retain and remove nitrate. This dissertation explores the role of productive, actively growing coastal …


Constitutive Models For Dynamic Strain Aging In Metals: Strain Rate And Temperature Dependences On The Flow Stress, Yooseob Song, Daniel Garcia-Gonzalez, Alexis Rusinek Apr 2020

Constitutive Models For Dynamic Strain Aging In Metals: Strain Rate And Temperature Dependences On The Flow Stress, Yooseob Song, Daniel Garcia-Gonzalez, Alexis Rusinek

Civil Engineering Faculty Publications

A new constitutive model for Q235B structural steel is proposed, incorporating the effect of dynamic strain aging. Dynamic strain aging hugely affects the microstructural behavior of metallic compounds, in turn leading to significant alterations in their macroscopic mechanical response. Therefore, a constitutive model must incorporate the effect of dynamic strain aging to accurately predict thermo-mechanical deformation processes. The proposed model assumes the overall response of the material as a combination of three contributions: athermal, thermally activated, and dynamic strain aging stress components. The dynamic strain aging is approached by two alternative mathematical expressions: (i) model I: rate-independent model; (ii) model …


Reliability Improvement On Feasibility Study For Selection Of Infrastructure Projects Using Data Mining And Machine Learning, Xi Hu Apr 2020

Reliability Improvement On Feasibility Study For Selection Of Infrastructure Projects Using Data Mining And Machine Learning, Xi Hu

Theses and Dissertations

With the progressive development of infrastructure construction, conventional analytical methods such as correlation index, quantifying factors, and peer review are no longer satisfactory in support for decision-making of implementing an infrastructure project in the age of big data. This study proposes using a mathematical model named Fuzzy-Neural Comprehensive Evaluation Model (FNCEM) to improve the reliability of the feasibility study of infrastructure projects by using data mining and machine learning. Specifically, the data collection on time-series data, including traffic videos (278 Gigabytes) and historical weather data, uses transportation cameras and online searching, respectively. Meanwhile, the researcher sent out a questionnaire for …


The Long-Term Outlook Of The Mississippi-Atchafalaya Bifurcation: A Convergence Of Engineering, Economics, And Deltaic Evolution, Thomas Mitchell Andrus Apr 2020

The Long-Term Outlook Of The Mississippi-Atchafalaya Bifurcation: A Convergence Of Engineering, Economics, And Deltaic Evolution, Thomas Mitchell Andrus

LSU Doctoral Dissertations

The most recent and currently active delta lobe of the Mississippi River (MR) is the Atchafalaya-Wax Lake lobe, which was initiated approximately 400 years ago as a result of MR stream capture by the Atchafalaya River (AR). This capture process accelerated in the early to mid-1900s but further progress was prevented by construction and operation of the Old River Control Structure (ORCS) Complex. Many recent studies indicate that MR system below the ORCS is on a retreating geologic trajectory due to contributing factors such as sea level rise, subsidence, faulting, and declining hydraulic stream power. Diversions along the Lower MR …


Post-Overlay Flexible Pavement Performance Modeling And Its Application In Sustainable Asphalt Overlay Policy Making, Chunfu Xin Apr 2020

Post-Overlay Flexible Pavement Performance Modeling And Its Application In Sustainable Asphalt Overlay Policy Making, Chunfu Xin

USF Tampa Graduate Theses and Dissertations

Highway pavement is a critical component of the highway transportation infrastructure. After the construction of a pavement system, pavement condition will deteriorate over time due to a combination effect of material aging, traffic loading, and environmental impact. To restore the pavement performance and to reduce its adverse effects on public users and environment, asphalt overlay activities are conducted frequently during the service life of a pavement. As a key component that bridges the overlay policies with future pavement performance, economic cost and environmental impact, the forecast accuracy of post-overlay pavement performance model is extremely important. However, most of previous studies …


Rapid Cross-Section Imaging With Magnetic And Impedance Sensors For Grout Anomaly Detection In External Post-Tensioned Tendons, Hani Freij Apr 2020

Rapid Cross-Section Imaging With Magnetic And Impedance Sensors For Grout Anomaly Detection In External Post-Tensioned Tendons, Hani Freij

USF Tampa Graduate Theses and Dissertations

Post-tensioned (PT) bridges have had severe corrosion issues with tendons that fail suddenly without prior notice. The corrosion of external post-tensioned tendons has been associated with grout deficiencies/anomalies from inadequate grouting. Deficiencies include voids, regions of chalky low strength grout, and regions where excessive water content or even free water is present. In those zones mechanical bonding of strand to the grout is degraded and, of more concern, the strand steel risks corrosion failure reducing the expected lifespan of the structure. As tendons are critical structural components, it is important to detect those deficiencies during inspection preferably by a cross …