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Articles 1 - 13 of 13
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Applications Of Geopolymer In Civil Engineering: Feasibility Study Of Loess Stabilization And Waste Concrete Recycling, Zhen Liu
LSU Doctoral Dissertations
The fast growing population and economic development have resulted in an increasing demand for residential and commercial buildings and infrastructures. However, there are problems identified to fulfill this demand, including that (1) problematic soils need to be treated/improved before the construction of building and infrastructures; (2) the Portland cement industry, which is used for concrete production and as the conventional soil stabilizer, is not environment friendly; (3) qualified natural aggregates for concrete production are being depleted; and (4) great amount of construction & demolition waste (C&D waste) is being produced every year. This means that green materials and recycling the …
Development Of Satellite-Assisted Forecasting System For Oyster Norovirus Outbreaks, Jiao Wang
Development Of Satellite-Assisted Forecasting System For Oyster Norovirus Outbreaks, Jiao Wang
LSU Doctoral Dissertations
Norovirus outbreaks can cause the closure of oyster harvesting waters and acute gastroenteritis in humans associated with consumption of contaminated raw oysters. The overall goal of this study was to develop a satellite-assisted forecasting system for oyster norovirus outbreaks. The forecasting system is comprised of three components: (1) satellite algorithms for retrieval of environmental variables, including salinity, temperature, and gage height, (2) an Artificial Neural Network (ANN) based model, called NORF model, for predicting relative risk levels of oyster norovirus outbreaks, and (3) a mapping method for visualizing spatial distributions of norovirus outbreak risks in oyster harvest areas along Louisiana …
Field Instrumentation And Testing To Study Set-Up Phenomenon Of Driven Piles And Its Implementation In Lrfd Design Methodology, Md Nafiul Haque
Field Instrumentation And Testing To Study Set-Up Phenomenon Of Driven Piles And Its Implementation In Lrfd Design Methodology, Md Nafiul Haque
LSU Doctoral Dissertations
This research study investigates the pile set-up phenomenon for clayey soils and develops the models to predict pile set-up resistance at a certain time after the end of driving (EOD). The increase of pile resistance after EOD is known as “pile set-up”. To fulfill this objective, a total number of twelve prestressed concrete (PSC) test piles were driven in different soil conditions of Louisiana. In addition, dynamic load tests (DLT) and static load tests (SLT) were usually performed to verify the axial resistances of piles at specific times after EOD, as well as to quantify the amount of increase in …
Uncertainty Analyses Of Climate Change Impact On Hydrologic Projections, Ehsan Beigi
Uncertainty Analyses Of Climate Change Impact On Hydrologic Projections, Ehsan Beigi
LSU Doctoral Dissertations
This study conducts uncertainty analysis on future region-scale hydrologic projections under the uncertain climate change projections of the IPCC Fifth and Forth Assessment Reports. The hierarchical Bayesian model averaging (HBMA) method is adopted to segregate and prioritize sources of climate projection uncertainty, obtain ensemble mean of hydrologic projection, and quantify the hydrologic projection uncertainty arising from individual uncertainty sources. This study deals with the choices of greenhouse gas (GHG) concentration trajectories, global climate models (GCMs), and GCM initial conditions as three major uncertainty sources in downscaled precipitation and temperature projections. The method is applied to investigate future hydrologic projections in …
Development And Optimization Of Non-Hydrostatic Models For Water Waves And Fluid-Vegetation Interaction, Ling Zhu
LSU Doctoral Dissertations
The primary objective of this study is twofold: 1) to develop an efficient and accurate non-hydrostatic wave model for fully dispersive highly nonlinear waves, and 2) to investigate the interaction between waves and submerged flexible vegetation using a fully coupled wave-vegetation model. This research consists of three parts. Firstly, an analytical dispersion relationship is derived for waves simulated by models utilizing Keller-box scheme and central differencing for vertical discretization. The phase speed can be expressed as a rational polynomial function of the dimensionless water depth, $kh$, and the layer distribution in water column becomes an optimizable parameter in this function. …
Sustainable Materials For Pavement Infrastructure: Design And Performance Of Asphalt Mixtures Containing Recycled Asphalt Shingles, Samuel B. Cooper, Jr
Sustainable Materials For Pavement Infrastructure: Design And Performance Of Asphalt Mixtures Containing Recycled Asphalt Shingles, Samuel B. Cooper, Jr
LSU Doctoral Dissertations
As the price of liquid asphalt continuously climb, methods are being sought to decrease material costs which will have less impact on ecological systems without compromising material or pavement performance. The use of recycled materials is one method that can replace a percentage of their virgin counterparts, thus reducing the negative impacts on the environment. Asphalt mixture performance is affected by the level of blending that occurs between aged and virgin asphalt binders. The interaction and compatibility of recycling agents (RAs) with recycled asphalt shingles (RAS) and reclaimed asphalt pavements (RAP) have not been thoroughly evaluated since the 1970s. To …
Probabilistic Performance-Based Hurricane Engineering (Pbhe) Framework, Vipin Unnithan Unnikrishnan
Probabilistic Performance-Based Hurricane Engineering (Pbhe) Framework, Vipin Unnithan Unnikrishnan
LSU Doctoral Dissertations
In modern times, hurricanes have caused enormous losses to the communities worldwide both in terms of property damage and loss of life. In light of these losses, a comprehensive methodology is required to improve the quantification of risk and the design of structures subject to hurricane hazard. This research develops a probabilistic Performance-Based Hurricane Engineering (PBHE) framework for hurricane risk assessment. The proposed PBHE is based on the total probability theorem, similar to the Performance-Based Earthquake Engineering (PBEE) framework developed by the Pacific Earthquake Engineering Research (PEER) Center, and to the Performance-Based Wind Engineering (PBWE) framework. The methodology presented in …
Applications Of Large Eddy Simulation To Study Flow And Sediment Transport In Open Channel Flows, Getnet Baynesagne Agegnehu
Applications Of Large Eddy Simulation To Study Flow And Sediment Transport In Open Channel Flows, Getnet Baynesagne Agegnehu
LSU Doctoral Dissertations
The motivation of this study is to extend applications of Large Eddy Simulation (LES) for typical open channel flows to elucidate the time dependent three dimensional flow and sediment transport features which are usually difficult to measure in experiments. Detailed investigations are performed on the unsteady features and, in particular, turbulent structures of the flow to demonstrate the great potential of eddy resolving methods. The instantaneous flow and sediment transport fields are investigated together with the existence of coherent structures. These structures together with ejection events (u' < 0, w' > 0), are responsible for the vertical and lateral transport of suspended sediment from …
Experimental Designs For Model Discrimination And Uncertainty Reduction In Groundwater Modeling, Hai Van Pham
Experimental Designs For Model Discrimination And Uncertainty Reduction In Groundwater Modeling, Hai Van Pham
LSU Doctoral Dissertations
Groundwater systems are complex and subject to multiple interpretations due to a lack of sufficient information. Different propositions (or alternatives) are often proposed to represent uncertain model components resulted in many conceptual models using the same data. Yet considering too many models may lead to high prediction uncertainty and may lose the purpose of model development. To decrease the prediction uncertainty due to conceptual model uncertainty, two experimental designs are proposed. The first experimental design intends to identify model propositions in each uncertain model component. A discrimination criterion is developed based on posterior model probability. Bayesian model averaging (BMA) is …
Investigating Wave Forces On Coastal Bridge Decks, Guoji Xu
Investigating Wave Forces On Coastal Bridge Decks, Guoji Xu
LSU Doctoral Dissertations
Tsunamis and hurricane induced waves are responsible for many coastal bridge failures, especially in the last decade. In the current study, three countermeasures (reducing the entrapped air, elevating the structures and rigidifying the structures) are considered, two wave types (solitary wave theory and Stokes wave theory) are chosen, and two bridge types (single bridge deck and twin bridge decks) are taken into account. Parametric studies are conducted based on Computational Fluid Dynamics (CFD) software ANSYS Fluent. This dissertation comprises two broad themes according to the wave types adopted. The first one is to make a great effort to investigate solitary …
Coupled Gradient Enhanced Damage - Viscoplasticity Model Using Phase Field Method, Navid Mozaffari
Coupled Gradient Enhanced Damage - Viscoplasticity Model Using Phase Field Method, Navid Mozaffari
LSU Doctoral Dissertations
The aim of this dissertation is developing a framework to describe damage evolution as a phase transformation in solid materials and couple it to the well-known Perzyna type viscoplastic model to account for inelastic behavior of ductile materials. To accomplish this task, the following steps have been performed. First, a new nonlocal, gradient based damage model is proposed for isotropic elastic damage using the phase field method in order to show the evolution of damage in brittle materials. The general framework of the phase field model (PFM) is discussed and the order parameter is related to the damage variable in …
Evaluation Of Volumetric And Mechanistic Properties Of Asphaltic Mixtures: Design, Production And Construction, Samuel Booth Cooper Iii
Evaluation Of Volumetric And Mechanistic Properties Of Asphaltic Mixtures: Design, Production And Construction, Samuel Booth Cooper Iii
LSU Doctoral Dissertations
There has long been an understanding that differences exist between the asphalt mixture designed in the laboratory and the asphalt mixture produced in the asphalt plant. Additionally, variations between the mixtures compacted in the laboratory and mixtures extracted from the roadway have been observed. There is concern that asphalt mixtures produced through the plant and further compacted on the roadway are not representative of asphalt mixtures designed in the laboratory. This is especially a concern when field specimens (i.e. roadway cores) are used to evaluate the quality of the asphalt mixture. For the first time, a national effort has been …
Connected Vehicle Technology: User And System Performance Characteristics, Osama Abdulmonaem Thabet Osman
Connected Vehicle Technology: User And System Performance Characteristics, Osama Abdulmonaem Thabet Osman
LSU Doctoral Dissertations
The emerging connected vehicle (CV) technology plays a promising role in providing more operable and safer transportation environments. Yet, many questions remain unanswered as to how various user and system characteristics of CV-enabled networks can shape the successful implementation of the technology to maximize the return on investment. This research attempts to capture the effect of multiple factors such as traffic density, market penetration, and transmission range on the communication stability and overall network performance by developing a new CONnectivity ROBustness (CONROB) model. The model was tested with data collected from microscopic simulation of a 195 sq-mile traffic network and …