Civil & Environmental Engineering Masters Theses

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Alginate Encapsulated Nanoparticle-Microorganism System for Trichloroethylene Remediation
(North Dakota State University, 2012) Shanbhogue, Sai Sharanya
Nanoscale zero-valent iron (NZVI) particles were encapsulated in calcium alginate capsules for application in environmental remediation. TCE degradation rates for encapsulated and bare NZVI were similar indicating no adverse effects of encapsulation on degradation kinetics. Microorganisms were separately encapsulated and used along with encapsulated NZVI and co-encapsulated in calcium alginate capsules. Batch experiments were performed to test the efficacy of the combined iron-Pseudomonas sp. (PpF1) system. The combined system removed 100% TCE over the first three hours of the experiment followed by 70% TCE removal post TCE re-dosing. Complete reduction of TCE was achieved by NZVI between 0-3 h and the second phase of treatment (3-36 h) was mostly achieved by microorganisms. Experiments conducted with co-encapsulated NZVI-D.BAV1 achieved 100% TCE removal. During the first three hours of the experiment 100% TCE removal was achieved by NZVI, and 100% removal was achieved post re-dosing where D.BAV1 accomplished the treatment.
Analyses of Highway Project Construction Risks, Performance, and Contingency
(North Dakota State University, 2010) Mohamed, Fahmy Diab
Past studies have highlighted the importance of risk assessment and management in construction projects and transportation industry, and have identified cost and time as the most important risks that transportation professionals want to understand and manage. The main focus of this study is to comprehensively analyze transportation construction risk drivers and identify the correlation of the significant risk drivers with project characteristics, cost growth, schedule growth, and project contingency. This study has adopted 31 relevant and significant programmatic and project-specific risk drivers from different past studies. These risk drivers have been analyzed and evaluated using survey responses from professionals in the context of highway transportation projects. Risk assessments including rating of the encountered risk drivers and their correlation with project characteristics have been carried out within the context of highway construction projects in the United States. Correlations of the construction project performance or risk measures, cost growth percentage, and schedule growth percentage, with the rating values of identified risk drivers values have enabled a better understanding of the impacts of risks and the risk assessment process for highway transportation projects. The impact of significant risk drivers on reported construction cost contingency amounts has also been analyzed. The purpose of this effort was to assess impact of ratings for cost impact, schedule impact, and relative importance of the identified risk drivers on contingency amounts. Predetermined method is the common way to calculate contingency amount in transportation projects. In this study parametric modeling has been used to analyze the relationship between predetermined contingency amounts in transportation projects with perceived risk rating values in order to understand how the expert judgments regarding risk ratings can be used in determination of contingency amounts.
Analysis and Evaluation of the Pedestrian Hybrid Beacon in School Zones
(North Dakota State University, 2010) Bittner, Michael Howard
Meeting dual objectives of pedestrian safety and motorist convenience at pedestrian crossings in school zones is an important and continuing challenge for all local communities. Pedestrian safety is influenced by pedestrian delays as well as motorist compliance of controls. Motorist convenience is influenced by the delay experienced by drivers. Conventional crosswalk control devices such as marked crosswalks and pedestrian signals are not always adequate or efficient in balancing these two crucial but conflicting objectives. The 2009 edition of the Manual on Uniform Traffic Control Devices (MUTCD) has paved the way for the use of a brand new crosswalk control device known as the pedestrian hybrid beacon (PHB). Previous research has provided evidence of this device's effectiveness in the area of motorist compliance and reduced motorist delay compared to traditional pedestrian signals. No prior research has been conducted on the PHB in the school zone context or on children pedestrians in general. This research has two objectives. The first objective was to analyze MUTCD Warrant 5 standards, which are designed for pedestrian signals in school zones, and the new PHB standards. This analysis will use pedestrian volume, vehicle volume, and gap availability on different test locations to conduct a comparative analysis of the two sets of standards. The purpose of this objective is to determine the transferability of the new MUTCD PHB standards in the school zone context. The second objective of this research was to evaluate three crosswalk control devices; marked crosswalks, pedestrian signals, and PHBs, for their ability to effectively address pedestrian safety and motorist convenience at school crossings. It was found that the PHB performed significantly better than traditional marked crosswalks but not markedly different than conventional pedestrian signals in the ability to balance the objectives of pedestrian safety and motorist convenience. The absence of improvements in performance of the PHB when compared to the pedestrian signal can be attributed to the fact that only 8.8% of motorists correctly utilized the PHB at the test location in Fargo, North Dakota. The most significant contribution of this thesis was finding that the current PHB standards in MUTCD are not transferable to the school zone context. For PHBs to be considered a viable option for engineers designing and controlling school crosswalks, it is essential that the MUTCD have school zone specific standards or guidance. The analysis carried out in this research provides insights into how such standards can be established and applied.
An Anisotropic Damage Mechanics Model for Concrete with Applications for Fatigue Loading and Freeze-Thaw Effects
(North Dakota State University, 2013) Reberg, Andrew Steven
It is well known that the formation and propagation of microcracks within concrete is anisotropic in nature, and has a degrading effect on its mechanical performance. In this thesis an anisotropic damage mechanics model is formulated for concrete which can predict the behavior of the material subjected to monotonic loading, fatigue loading, and freeze-thaw cycles. The constitutive model is formulated using the general framework of the internal variable theory of thermodynamics. Kinetic relations are used to describe the directionality of damage accumulation and the associated softening of mechanical properties. The rate independent model is then extended to cover fatigue loading cycles and freeze-thaw cycles. Two simple softening functions are used to predict the mechanical properties of concrete as the number of cyclic loads as well as freeze-thaw cycles increases. The model is compared with experimental data for fatigue and freeze-thaw performance of plain concrete.
Application of Damage Mechanics to Describe the Behavior of Concrete under Fatigue and Freeze-Thaw Processes
(North Dakota State University, 2015) Saboori, Ashkan
Concrete has been used in dams, bridges, and highway pavements in which freeze-thaw process and cyclic loading are important factors affecting its mechanical behavior. Damage caused by frost expansion is a primary concern when designing concrete structures in cold regions. The onset of damage within concrete can be accelerated when a freeze-thaw cycle occurs while a structure is subjected to an external loading. Also, concrete under fatigue loading gradually loses its strength with an increase in the number of load cycles. It is widely accepted that concrete shows more flexible behavior under freeze-thaw process and fatigue loading due to wide-spread microcracks occurred during both conditions. Therefore, concrete deteriorates under such processes and its mechanical properties such as strength, stiffness, and ultimate strain will change. In order to predict the mechanical behavior of concrete under such circumstances, a rate independent model is extended to cover fatigue loading and freeze-thaw cycles.
Assessment of Molecularly Imprinted Polymers as Phosphate Sorbents
(North Dakota State University, 2017) Ritt, Cody
Wastewater effluents and agricultural runoff are major sources of phosphorus overloading in surface waters. Phosphorus overloading ignites eutrophication, which devastates aquatic ecosystems. On the other hand, phosphorus, which is currently produced from phosphate rock, is a critical component of fertilizer mixes. However, the world is predicted to face a shortage of phosphate supply beyond 2033 due to unsustainable mining. This research aims to develop a polymeric sorbent that recovers low-concentration phosphorus for eutrophication prevention and fertilizer reuse. Available polymer-based products have underwhelmed expectations by having poor selectivity or lacking appropriate biodegradation rates. This research identified molecularly imprinted polymers (MIPs) as possible sorbents for overcoming the deficiencies of reported technologies. Screening of several MIPs resulted in one potentially feasible MIP for phosphate sorption. Further studies showed a sorption capacity of ~28 mg PO43--P/g and partial phosphate-selectivity. Potential phosphate removal mechanisms were identified, providing foresight into MIPs’ viability as phosphorus sorbents.
Calibrating Smartphones for Monitoring Road Condition on Paved and Unpaved Roads
(North Dakota State University, 2018) Hu, Liuqing
Transportation agencies report the localization of roadway anomalies that could cause serious hazards to the traveling public. However, the high cost and limitations of present technical prevent scaling the road monitoring to all roadways. Especially the unpaved road, because of the complexity of unpaved road. Using smartphone application as road condition data collection tool offer an attractive alternative because of its potential to monitor all roadways in real time and its low cost. However, the sensor sensitivity and sampling frequency of different smartphones may vary significantly, which challenge the confidence of using smartphones for actual pavement condition assessment applications. This study tends to solve this challenge by calibrating different smartphones using two different calibrating methods including calibrating towards reference or average road roughness.
Carboxymethyl Cellulose Surface Treatment Method to Disperse Carbon Nanotubes in Smart Cementitious Materials
(North Dakota State University, 2019) Yang, Xinyuan
An innovative surface treatment method was proposed using carboxymethyl cellulose (CMC) to surface-treat carbon nanotubes (CNTs) for a consistent dispersion in cementitious materials to achieve high force detection sensitivity. This CMC surface treatment method was compared with two traditional methods, direct mixing and surfactant surface treatment, to validate dispersion effectiveness. Experimental results demonstrated that CMC and CNTs combined can increase force sensitivity of the smart cementitious material more than six times compared with direct mixing and more than three times compared with the surfactant surface treatment. CMC surface treatment significantly improved CNTs dispersion consistency. For CMC surface treatment, the comparison of 0.1%, 0.3% and 0.5% of CNTs by weight to cement demonstrated all percentages showed consistent laboratory dynamic force sensing results. Furthermore, CNTs percentage did not differ for force sensitivity. All experiments indicated the proposed CMC surface treatment method is an effective dispersion method for CNTs in smart cementitious materials.
Characterization of Mechanical Adhesion Failure in Epoxy Nanocomposites by Acoustic Emission Method
(North Dakota State University, 2021) Pearson, Matthew William
Polymeric nanocomposite coatings are used to protect metallic components in a variety of civil structures from corrosive agents. The adhesion between a coating and its substrate is not yet fully understood. In this study, the relationship between mechanical delamination of epoxy coating systems and the acoustic noise generated during failure was explored using acoustic emission. Three metrics were compared: a) mechanical loading data, b) post-test image processing, and c) acoustic emission data to gain insight into the coating-substrate layer. Neat epoxy and three epoxy nanocomposite systems modified with carbon nanotubes (CNTs), graphene (GNPs), and silica (SiO2) were casted on mild steel at two different thicknesses via draw-down bar. Test results demonstrated that there was a correlation between mechanical adhesion/cohesion strength and resulting acoustic noise. The findings suggested that the higher thickness in the reinforced coatings provided for a greater cohesion failure area as well as higher volume of acoustic energy.
Characterization of Surface Microtopography and Determination of Hydrotopographic Properties
(North Dakota State University, 2012) Chi, Yaping
Spatial characterization of surface microtopography is important in understanding the overland flow generation and the spatial distribution of surface runoff. In this study, fractal parameters (i.e., fractal dimension D and crossover length l) and three hydrotopographic parameters, random roughness (RR) index, maximum depression storage (MDS), and the number of connected areas (NCA), have been applied to characterize the spatial complexity of microtopography. Clear and meaningful relationships have been established between these parameters. The RR was calculated as the standard deviation of the processed elevation, and the fractal parameters were calculated with the semivariogram method. The puddle delineation program was applied in this study to spatially delineate soil surface and to accurately determine MDS and NCA. It has been found that fractal parameters can better characterize surface microtopography. More importantly, fractal and anisotropic analyses can help to better understand the overland flow generation process.
Clay Fluid Interactions in Montmorillonite Swelling Clays: A Molecular Dynamics and Experimental Study
(North Dakota State University, 2012) Patwary, Md Zillur R.
Swelling clays cause tremendous amounts of damage to infrastructure. For the effective prevention of detrimental effects of these clays, and to optimize the beneficial properties for industrial applications it is necessary to clearly understand the fundamental mechanisms of swelling of clays. In this study, we studied the effect of fluid polarity on swelling and flow properties of swelling clays using molecular modeling and experimental technique for bridging the molecular level phenomenon of these clays with microstructure change, particle breakdown and macro scale swelling and flow properties. A wide range of fluids (Dielectric Constant 110 to 2.4) were used, those are also commonly present in landfill leachates. We were able to tie the properties of swelling clays at different length scales. Then, we simulated the solvation of clay sheets, studied the effect of discrete charge distribution, contribution of edge charges on swelling clays and discussed some fundamental assumptions associated with double layer theories.
Coating of NZVI Particles With Modified Starch: Colloidal Stability and Nitrate Reduction Studies
(North Dakota State University, 2015) Pate, Mary Francis
Nanoscale-zero valent iron (NZVI) is an effective groundwater remediation media because it can quickly reduce and absorb contaminants. However, NZVI quickly agglomerates in aqueous systems, reducing its remediation capacity. This work investigated coating NZVI with native and modified rice, wheat, maize, and tapioca starches to improve colloidal stability. Colloidal stability studies were conducted with native and commercially available starches; tapioca starch modified with 2-Octen-l-ylsuccinic anhydride (OSA) was the best. Four concentrations of OSA-tapioca starch were prepared (3, 15, 35, and 50% w/w). NZVI coated with 35% OSA-modified tapioca starch (concentration = 10 g L-1) kept 66% of the coated particles suspended after 2 hours (compared to 4% of bare particles, p = 0.000). Bare NZVI reduced significantly more nitrate (20 mg L-1) than coated NZVI (p =0.000). Bare and coated NZVI provided the same nitrate reduction at 40 and 60 mg L-1 (p = 0.939 and p = 0.815, respectively).
A Comparative Study of Nitrification in Fargo and Moorhead Distribution Networks
(North Dakota State University, 2012) Portlock, Daniel
Nitrification in water distribution networks has become a growing concern for water supplies in the United States. The use of chloramines as a disinfectant in distribution pipe networks has become increasingly popular to reduce the disinfectant byproducts that are formed with free chlorine. In chloraminated systems there is potential for nitrification to occur because it reduces chloramine residuals. As chloramines decompose in the network, ammonia is released. Nitrifiers oxidize ammonia into nitrites, which react with chloramines resulting in its further reduction. As this cycle continues, chloramines will be consumed faster in the network, causing regrowth of heterotrophic bacteria. A study was conducted to compare the Fargo and Moorhead distribution networks for the occurrence of nitrification and their potential to deteriorate water quality. Each distribution network was analyzed independently for variations in operational conditions and water quality parameters that can serve as indications of nitrification in a distribution network.
Comparisons of Energy Dissipation in Structural Devices with Foundation Soil During Seismic Loading
(North Dakota State University, 2010) Saravanathiiban, Duraisamy Soundararajan
The effectiveness of structural energy dissipation mechanisms such as passive energy dissipation devices and base isolation methods used in seismic design depends on their capacity, ductility, energy dissipation, isolation, and self-centering characteristics. Though rocking shallow foundations could also be designed to possess many of these desirable characteristics, current seismic design codes often avoid nonlinear behavior of soil and energy dissipation beneath foundations because of concerns about permanent deformations at foundation level. This thesis compares the effectiveness of energy dissipation in foundation soil with structural energy dissipation devices during seismic loading. Numerical simulations of structures with and without energy dissipation devices were carried out to systematically study the seismic energy dissipation in structural elements and energy dissipation devices. The numerical model was validated using shaking table experimental results on model frame structures with and without energy dissipation devices. The energy dissipation in the structure, drift ratio, and the force and displacement demands on the structure are compared with energy dissipation characteristics of rocking shallow foundations as observed in centrifuge experiments, where shallow foundations were allowed to rock on dry sandy soil stratum during dynamic loading. The comparisons of results clearly indicate that foundation (rocking) energy dissipation mechanism is as efficient as structural passive energy dissipation devices. For the structures with energy dissipating devices, about 70% to 90% of the seismic input energy is dissipated by energy dissipating devices, while foundation rocking dissipates about 30% to 90% of the total seismic input energy in foundation soil (depending on static factor of safety). Inclusion of energy dissipating braces increases the base shear force transmitted to the structure, while normalized base shear forces transmitted to the foundation during rocking are smaller than those of the structures with energy dissipating devices because of the isolation effect of rocking foundations. If properly designed (with reliable capacity and tolerable settlements), adverse effects of foundation rocking can be minimized while taking advantage of the favorable features of foundation rocking, and hence they can be used as efficient and economical seismic energy dissipation mechanisms in buildings and bridges.
Comparitive Analysis of Turbidity and Organics Removal in Biological Activated Carbon and Anthracite-Sand Filters in the Moorhead Water Treatment Plant
(North Dakota State University, 2019) von Hagen, Emily
The source water for the Moorhead Water Treatment Plant (MWTP) exhibits high concentrations of total organic carbon (TOC) throughout the year and seasonal taste and odor (T&O) events. To prevent biological regrowth in the distribution system there is a need to improve organics removal in the existing biological anthracite-sand filters, especially during cold water conditions when a significant decrease in removal efficiencies are observed. Three types of granular activated carbon (GAC) were selected for a pilot study to evaluate the potential of enhanced organics and T&O removal in biological activated carbon (BAC) filters compared to anthracite-sand. Turbidity removal was also evaluated to ensure regulatory requirements could be met with BAC filters. The overall performance of the BAC filters demonstrated a significant improvement over anthracite-sand. The bituminous coal-based GACs outperformed the coconut-based GAC and exhibited surface characteristics which may have a significant impact on the removal of organics, T&O, and turbidity.
Cumulative-Anticipative Car-Following Model for Enhanced Safety in Autonomous Vehicles
(North Dakota State University, 2020) Yang, Xinyi
As the rapid development of smart cities, autonomous vehicles are considered to be the future ground transportation measure which provides many benefits over traditional human-driving vehicles. However, there will be decades before the autonomous vehicles fully penetrate, during when human-drivers will share the same road systems with the autonomous vehicles, where the majority of accidents associated with autonomous vehicles are induced by the operation inconsistency of human drivers, which can be avoided if there is communication between the autonomous vehicles and the infrastructure (V2I). This study develops cumulative-anticipative car-following (CACF) model for autonomous vehicles based on the Cooperate Adaptive Cruise Control/ Adaptive Cruise Control (CACC/ACC) model by considering cumulative influences from multiple preceding vehicles. The simulation results from 128 simulation runs using the micro-simulator VISSIM showed that the CACF model can improve the safety and traffic congestions compared to the Wiedemann 99, the ACC, and the CACC models.
Damage Localization of Slab-on-Girder Bridges Through Vibration Characteristics
(North Dakota State University, 2015) Telste, Michael Andrew
An incompletely documented bridge 09-125-16 in Cass County, ND was tested by Bridge Diagnostics, Inc. (BDI). A Grillage numerical model is created with their field data to simulate the bridge responses due to traffic loads. A validated bridge model matching the field test data is developed. Based on the validated numerical model, loading of the corresponding bridge under different damage scenarios is performed to capture the change of displacement mode shapes. Using the difference of these displacement mode shape data, a modified curvature method is suggested for identifying damage in bridges, which is shown successfully through the modeling results of bridges with fictitious damages. An in-lab experiment of a steel plate without damage under impact forces is adopted to produce vibration data. The modified curvature is then computed using the experimental mode shape data and its change is found to correlate very well as anticipated by the suggested theory.
Design of Structural Vibration Control Using Smart Materials and Devices for Earthquake-Resistant and Resilient Buildings
(North Dakota State University, 2017) Azimi, Mohsen
Major earthquakes in recent years have highlighted the big concern of modern seismic design concept for the resilience of buildings. The overall goals of this thesis aim to design structural vibration control using smart materials and devices and to elucidate the factors determining their robustness, feasibility, and adaptability for earthquake-resistant and resilient buildings. The study mainly includes a) integrated wavelet-based vibration control with damage detection; b) shape memory alloy to eliminate the residual deformations; c) a mass damper for highly irregular tall buildings; and d) soil-structure interaction effects on the buildings. The robustness, feasibility, and adaptability of these proposed studies for earthquake-resistant and resilient buildings are evaluated using various performance measures. The findings of the study reveal that the structural vibration control strategies could advance the current-of-art knowledge in seismic risk mitigation as well as high system adaptability.
Detection of Two-Dimensional Internal Cracks in Concrete Using Point Strain Sensors
(North Dakota State University, 2020) Alshandah, Mohanad
Tensile cracking in the concrete can destroy the structural frame since it induces water penetration in structure and foundation. For instance, in concrete pavements, cracking increases the potential for pavement distress, the probability of accidents occurring, and the damages for vehicles. Therefore, monitoring techniques to detect hidden internal cracking in concrete such as bottom-up cracks are necessary to ensure the safety of the infrastructure by distinguishing early signs of excessive damage. This study presents an approach to detect internal concrete cracks especially bottom-up cracks using point strain sensors. The stress intensity principle is used in this study to locate and estimate the growth of the cracks. Based on the stress intensity principle, theoretical derivations have been conducted to use the point strain sensors in concrete structures to detect both single and multiple bottom-up cracks. For single crack detection, laboratory experiments showed an average measurement accuracy of 85.76%. For multiple cracks, laboratory tests performed using reinforced concrete beams and the average measurement accuracy was achieved to be over 80%. With the validation in the lab, future efforts are expected to be performed in the field to provide an alternative technique to detect hidden internal cracks in concrete structures, especially pavements.
Development of Operational Strategies to Minimize Bromate Formation in the Moorhead Water Treatment Plant
(North Dakota State University, 2014) Young, Kevin Bradley
A recent study at the Moorhead water treatment plant (MWTP) determined that bromate formed during ozone disinfection and, at times, exceeded the maximum contaminant level (MCL) of 10 parts per billion (ppb) in the summer months. Operational data showed that bromate formation was directly related to raw water bromide concentration and control of the ozone system. This study was conducted with the purpose of developing and implementing operational strategies to minimize bromate formation in the MWTP. Several operational changes, including selection of source water based on bromide concentration and controlling ozone addition in a manner that reduces the ozone dose used to achieve disinfection, were implemented and were effective at minimizing bromate formation in the ozone chambers. The bromate concentration in the finished drinking water was significantly reduced and only a few samples contained greater than 10 ppb bromate.

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