Civil and Environmental Engineering Commons^™

A Bayesian Network-Based Methodology For Improved Bridge Load Rating And Asset Management, Jeffery Mark Roberts

Dissertations and Theses

From the day a new structure is made available for use, to the day that the structure is no longer able to fulfill an intended purpose, structural safety is a vital interest. Managing a portfolio of structures can be a difficult undertaking for an asset manager, particularly if different types of structures are being maintained. The goal is to manage assets in the most efficient manner which can be influenced by, at a minimum, safety and financial concerns.

A potential tool for an asset manager or owner is the use of Bayesian Networks (BNs). When a BN is used to …

Stochastic Seismic Response Analysis Of Engineering Site Considering Correlations Of Critical Soil Dynamic Parameters, Zi-Lan Zhong, Yue-Bo Shi, Jin-Qiang Li, Mi Zhao, Xiu-Li Du

Rock and Soil Mechanics

This paper presents a method to generate random samples of soil dynamic shear modulus and dynamic damping curves with full consideration of the correlations of critical soil dynamic parameters to investigate the influence of their uncertainties on the engineering site seismic response in the implementation of equivalent linear method. A one-dimensional (1D) equivalent linear site seismic response analysis program, which serves stochastic dynamic response analysis of the engineering site, has been developed in MATLAB. A 1D free field model for the typical layered engineering sites of site class II is established in this study. The target response spectra, which are …

Uncertainties In The Projected Patterns Of Wave-Driven Longshore Sediment Transport Along A Non-Straight Coastline, Amin Reza Zarifsanayei, José A. A. Antolínez, Amir Etemad-Shahidi, Nick Cartwright, Darrell Strauss, Gil Lemos

Research outputs 2022 to 2026

This study quantifies the uncertainties in the projected changes in potential longshore sediment transport (LST) rates along a non-straight coastline. Four main sources of uncertainty, including the choice of emission scenarios, Global Circulation Model-driven offshore wave datasets (GCM-Ws), LST models, and their non-linear interactions were addressed through two ensemble modelling frameworks. The first ensemble consisted of the offshore wave forcing conditions without any bias correction (i.e., wave parameters extracted from eight datasets of GCM-Ws for baseline period 1979–2005, and future period 2081–2100 under two emission scenarios), a hybrid wave transformation method, and eight LST models (i.e., four bulk formulae, four …

Accuracy And Uncertainty In Traffic And Transit Ridership Forecasts, Jawad Mahmud Hoque

Theses and Dissertations--Civil Engineering

Investments of public dollars on highway and transit infrastructure are influenced by the anticipated demands for highways and public transportations or traffic and transit ridership forecasts. The purpose of this study is to understand the accuracy of road traffic forecasts and transit ridership forecasts, to identify the factors that affect their accuracy, and to develop a method to estimate the uncertainty inherent in those forecasts. In addition, this research investigates the pre-pandemic decline in transit ridership across the US metro areas since 2012 and its influence on the accuracy of transit forecasts.

The sample of 1,291 road projects from the …

Sources Of Variability And Uncertainty In Food-Energy-Water Nexus Systems, Heydi Calderon-Ambelis, Deepak R. Keshwani

Department of Biological Systems Engineering: Papers and Publications

A nexus approach contributes to the strategic allocation of resources to secure food, energy, and water for the world population. Integrated models considering the complex interactions across food, energy, and water (FEW) enhance decision-making and strategic planning towards resilience. However, a significant number of the existing integrated models leave unaddressed the inherent variability and uncertainty present in the FEW sectors. Here, we review the importance of characterizing variability over spatial and temporal scales and the importance of decreasing the uncertainty present within a FEW nexus systems. The review also discusses existing modeling tools that address variability and uncertainty on single …

Accounting For Critical Attributes And Uncertainty In Flow-Ecology Relationships, Elizabeth Decker Morgan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Environmental flows are used to maintain streamflow for aquatic species in rivers while also sustaining human water requirements. While there are many approaches to develop environmental flows, they all rely on a strong conceptual understanding of flow-ecology relationships, which are often uncertain. Uncertainty in flow-ecology relationships can stem from using limited data to develop or test relationships or an incomplete understanding of the attributes inherent to each relationship, such as climate and land conditions. Accounting for these attributes and uncertainty in flow-ecology relationships is critical given mounting interest to develop and implement environmental flows at large scales, often with limited …

Computational Modeling For Decision-Making Under Climate Change Uncertainty: Reservoir Simulation Game, Julianne Quinn

All ECSTATIC Materials

Almost every decision you make is under uncertainty. Will I need a rain jacket in the afternoon? Will they say yes if I ask them out? Is 1 hour enough time to finish this assignment? Oftentimes, we can use computational modeling to simulate different scenarios of what might happen in the future to inform what decisions are best on average, or what decisions minimize the worst case outcome. For example, you could decide what player to draft for your Fantasy Football team by simulating player performance. In this activity, we will simulate how much water to release from a dam …

Robustness And Accuracy Bounds Of Model-Based Structural Health Monitoring, Nestor Ramon Polanco

Graduate College Dissertations and Theses

The strength and stiffness of structures degrade with time due to a combination of external forces and environmental conditions. A vehicular bridge, an offshore platform, a ship hull, or a wind turbine are examples of structures that for decades must endure cumulative degradation of their mechanical properties due to cyclic loading. Fatigue-induced damage typically starts at the exterior surface of the component unless microscopic or macroscopic imperfections are present in the material's structure. Structural Health Monitoring (SHM) provides a scientific non-destructive framework to estimate the structure's current state and remaining service life. In many model-based structural health monitoring applications, the …

Sensitivity Analysis Of Data-Driven Groundwater Forecasts To Hydroclimatic Controls In Irrigated Croplands, Alessandro Amaranto, Francesca Pianosi, Dimitri Solomatine, Gerald Corzo-Perez, Francisco Munoz-Arriola

Department of Biological Systems Engineering: Papers and Publications

In the last decades, advancements in computational science have greatly expanded the use of artificial neural networks (ANNs) in hydrogeology, including applications on groundwater forecast, variable selection, extended lead-times, and regime-specific analysis. However, ANN-model performance often omits the sensitivity to ob- servational uncertainties in hydroclimate forcings. The goal of this paper is to implement a data-driven modeling framework for assessing the sensitivity of ANN-based groundwater forecasts to the uncertainties in observational inputs across space, time, and hydrological regimes. The objectives are two-folded. The first objective is to couple an ANN model with the PAWN sensitivity analysis (SA). The second objective …

Field Assessment Of Interreplicate Variability From Eight Electromagnetic Soil Moisture Sensors, Tsz Him Lo, Daran Rudnick, Jasreman Singh, Hope Njuki Nakabuye, Abia Katimbo, Derek M. Heeren, Yufeng Ge

Department of Biological Systems Engineering: Papers and Publications

Interreplicate variability—the spread in output values among units of the same sensor subjected to essentially the same condition—can be a major source of uncertainty in sensor data. To investigate the interreplicate variability among eight electromagnetic soil moisture sensors through a field study, eight units of TDR315, CS616, CS655, HydraProbe2, EC5, 5TE, and Teros12 were installed at a depth of 0.30 m within 3 m of each other, whereas three units of AquaSpy Vector Probe were installed within 3 m of each other. The magnitude of interreplicate variability in volumetric water content (θ_v) was generally similar between a static …

Groundwater Management Optimization And Saltwater Intrusion Mitigation Under Uncertainty, Jina Yin

LSU Doctoral Dissertations

Groundwater is valuable to supply fresh water to the public, industries, agriculture, etc. However, excessive pumping has caused groundwater storage degradation, water quality deterioration and saltwater intrusion problems. Reliable groundwater flow and solute transport modeling is needed for sustainable groundwater management and aquifer remediation design. However, challenges exist because of highly complex subsurface environments, computationally intensive groundwater models as well as inevitable uncertainties. The first research goal is to explore conjunctive use of feasible hydraulic control approaches for groundwater management and aquifer remediation. Water budget analysis is conducted to understand how groundwater withdrawals affect water levels. A mixed integer multi-objective …

Fine Sediment Modeling During Storm-Based Events In The River Bandon, Ireland, Juan T. Garcia, Joseph R. Harrington

Publications

The River Bandon located in County Cork (Ireland) has been time-continuously monitored by turbidity probes, as well as automatic and manual suspended sediment sampling. The current work evaluates three different models used to estimate the fine sediment concentration during storm-based events over a period of one year. The modeled suspended sediment concentration is compared with that measured at an event scale. Uncertainty indices are calculated and compared with those presented in the bibliography. An empirically-based model was used as a reference, as this model has been previously applied to evaluate sediment behavior over the same time period in the River …

Identification And Reduction Of Uncertainties In Watershed-Scale Flow And Water Quality Modeling, Maryam Roostaee

LSU Doctoral Dissertations

This study identified important uncertainties affecting watershed-scale flow and water quality simulations and recommended modeling options for reducing the uncertainties by means of the Hydrological Simulation Program-FORTRAN (HSPF) model. Specifically, parameter-induced uncertainties in HSPF model were estimated along with uncertainties associated with DEM resolutions and sources. National Elevation Dataset (NED) DEMs with original and resampled resolutions of 3.5, 10, 30 and 100m were utilized for manual and automatic delineation of three watersheds with different gradients in HSPF model to identify the effects of DEM resolution, DEM resampling, delineation method and watershed gradient on the simulation of streamflow, nitrate (NO_{3 …}

Modelling Of Future Flood Risk Across Canada Under Climate Change, Ayushi Gaur

Electronic Thesis and Dissertation Repository

Climate change has induced changes in key climate variables and hydrological cycle in Canada. In this study, future runoff projections made by 21 GCMs following four Representative Concentration Pathways (RCPs) are used as inputs into a macro-scaled hydrodynamic model: CaMa-Flood to simulate 25 km resolution daily streamflow across Canada for historical (1961-2005) and future (2061-2100) time-periods. Future changes in flood-hazard as a consequence of changes in flooding frequencies of historical 100-year and 250-year return period flood events, and changes in the month of occurrence of extreme flows are analyzed. Changes in flood risk at Canada’s 100 most populous cities and …

Life Cycle Assessment In Foundry Sand Reclamation – Comparison Of Secondary Reclamation Processes, Samuel Keith Ghormley

Department of Environmental Engineering: Theses and Student Research

Foundries represent a significant part of the base of the world’s economy and as a sector are one of the largest consumers of energy and producers of solid waste in the United States. Sand casting foundries use approximately 5-10% of their total energy on sand handling processes. By adding a secondary sand reclamation process, foundries can expect to become more energy efficient as well as reducing solid waste from the foundry. To measure the broader environmental impacts, life cycle assessment (LCA) can be used. The goal of the current research was to examine a medium-sized foundry in the United States …

Performance-Based Liquefaction Triggering Analyses With Two Liquefaction Models Using The Cone Penetration Test, Alex Michael Arndt

Theses and Dissertations

This study examines the use of performance-based engineering in earthquake liquefaction hazard analysis with Cone Penetration Test data (CPT). This work builds upon previous research involving performance-based liquefaction analysis with the Standard Penetration Test (SPT). Two new performance-based liquefaction triggering models are presented herein. The two models used in this liquefaction analysis are modified from the case-history based probabilistic models proposed by Ku et al. (2012) and Boulanger and Idriss (2014). Using these models, a comparison is made between the performance-based method and the conventional pseudo-probabilistic method. This comparison uses the 2014 USGS probabilistic seismic hazard models for both methods. …

Methods For Incorporating Ecological Impacts With Climate Uncertainty To Support Robust Flood Management Decision-Making, Caitlin M. Spence

Doctoral Dissertations

Modern and historic flood risk management involves accommodating multiple sources of sources of uncertainty and potential impacts across a broad range of interrelated sectors. Sources of uncertainty that affect planning include internal climate variability, anthropogenic changes such as land use and system performance expectations, and more recently changes in climatology that affect the resources supporting the system. Flood management systems potentially impact human settlements within and beyond the systems’ scope of planning, local weather patterns, and associated ecological systems. Federal guidelines across nations have called for greater consideration of uncertainty and impacts of water resources planning projects, but methods for …

Predictive Modeling Of Riverine Constituent Concentrations And Loads Using Historic And Imposed Hydrologic Conditions, Mark Hagemann

Doctoral Dissertations

This research was principally concerned with the task of quantifying dissolved and suspended constituents carried in river water when direct measurements are not available. This is a question of scientific and societal relevance, and one with a long history of study and a great deal of remaining difficulty. The traditional approach to estimating these quantities, linear regression models (LMs), suffers from poor flexibility and high subsequent bias in many applications. This research applied semiparametric generalized additive models (GAMs), a more flexible class of regression models, evaluated their performance in various locations and conditions, and applied them in a proactive modeling …

A Comprehensive Decision Support Framework In The Front-End Phase Of Major Transportation Projects, Nahid Vesali Mahmoud

FIU Electronic Theses and Dissertations

Identifying the best project alternative is a critical challenge facing major transportation projects (MTPs) at the front-end phase. The increasing complexity and dynamism of MTPs have imposed substantial uncertainties and subjectivities in the decision-making process. Despite the efforts made in previous studies, a stochastic framework to facilitate the comprehensive assessment is still missing.

In this research, a stochastic decision support framework has been developed to cope with the considerable uncertainties in MTPs. The features of the proposed decision support framework are achieved by using the Bayesian belief network modeling technique to provide a comprehensive registry of the relevant decision factors, …

Using Multi-Objective Optimization To Support Urban Planning, Jonas Schwaab, Kalyanmoy Deb, Erik Goodman, Sven Lautenbach, Maarten Van Strien, Adrienne Grêt-Regamey

International Congress on Environmental Modelling and Software

Globally urban growth destroys fertile soils and endangers food security. Fertile soils are often located in the vicinity of existing urban areas. Thus, preserving high-quality soils often conflicts with the objective of compact city development. Urban planners have to account for both of these and many other objectives and react to political decisions which put a higher weight on some of them. In addition, urban planners have to deal with uncertain projections on population growth and the demand for housing. We used a multi-objective evolutionary algorithm to show for a case study region in Switzerland how robust urban growth patterns …

The Stability And Ecophysiological Realism Of Calibrated Parameters In A Detailed Vegetation Model (Waves), R. W. Vervoort, J. D. Henry, M. Gharun, M. A. Adams

International Congress on Environmental Modelling and Software

WAVES is a daily time-step one-dimensional vegetation, water and energy transfer model that has been used extensively across Australia (and globally) to simulate ecohydrological processes. In particular it has been used extensively for assessing future recharge under climate change. A literature review suggests parameter values from the user manual are most commonly used in research. This suggests that further investigation into the stability and equifinality of the parameters might be warranted, specifically since the model is used for scenario studies. This study made use of an extensive sapflow and soil moisture data set for 7 tree vegetation sites in the …

Using Scenario Analysis To Investigate Uncertainty In Water Resource Management, Baihua Fu, Joseph Guillaume, Mike Asher, Tony Jakeman

International Congress on Environmental Modelling and Software

Water resource management is a challenging task due to the complexity and uncertainty of the environmental systems and challenges of addressing multiple stakeholder perspectives. A crucial issue is therefore in specifically understanding if and how we can make decisions under such deep uncertainty.

We examined this issue in a case study which estimates groundwater sustainability, farm profit and ecological outcomes of many drivers (e.g. climate change, water policy, farm practices). An integrated model was developed for this purpose. It encompasses a surface and groundwater model, water allocation rules, a farm decision and crop model and an ecology model. Scenarios were …

Combining Interval And Probabilistic Uncertainty In Engineering Applications, Andrew Martin Pownuk

Open Access Theses & Dissertations

In many practical application, we process measurement results and expert estimates. Measurements and expert estimates are never absolutely accurate, their result are slightly different from the actual (unknown) values of the corresponding quantities. It is therefore desirable to analyze how this measurement and estimation inaccuracy affects the results of data processing. There exist numerous methods for estimating the accuracy of the results of data processing under different models of measurement and estimation inaccuracies: probabilistic, interval, and fuzzy. To be useful in engineering applications, these methods should provide accurate estimate for the resulting uncertainty, should not take too much computation time, …

Conjunctive Management Of Water Resources Under Climate Change Projection Uncertainty, Amir Mani

LSU Doctoral Dissertations

Goal of this study is to investigate the impacts of climate change projection uncertainty on conjunctive use of water resources. To pursue this goal first, a conjunctive-use model is developed for management of groundwater and surface water resources via mixed integer linear fractional programming (MILFP). The conjunctive management model maximizes the ratio of groundwater usage to reservoir water usage. A conditional head constraint is imposed to maintain groundwater sustainability. A transformation approach is introduced to transform the conditional head constraint into a set of mixed integer linear constraints in terms of groundwater head. A supply network is proposed to apply …

Stochastic Optimization Of Supply Chain Risk Measures –A Methodology For Improving Supply Security Of Subsidized Fuel Oil In Indonesia, Adinda Yuanita, Andi Noorsaman Sommeng, Anondho Wijonarko

Makara Journal of Technology

Monte Carlo simulation-based methods for stochastic optimization of risk measures is required to solve complex problems in supply security of subsidized fuel oil in Indonesia. In order to overcome constraints in distribution of subsidized fuel in Indonesia, which has the fourth largest population in the world—more than 250,000,000 people with 66.5% of productive population, and has more than 17,000 islands with its population centered around the nation's capital only—it is necessary to have a measurable and integrated risk analysis with monitoring system for the purpose of supply security of subsidized fuel. In consideration of this complex issue, uncertainty and probability …

Inter-Laboratory Variation In The Chemical Analysis Of Acidic Forest Soil Reference Samples From Eastern North America, D. S. Ross, S. W. Bailey, R. D. Briggs, J. Curry, I. J. Fernandez, G. Fredriksen, C. L. Goodale, P. W. Hazlett, P. R. Heine, C. E. Johnson, J. T. Larson, G. B. Lawrence, R. K. Kolka, R. Ouimet, D. Paré, D. De B. Richter, C. D. Schirmer, R. A. Warby

Civil and Environmental Engineering

Long-term forest soil monitoring and research often requires a comparison of laboratory data generated at different times and in different laboratories. Quantifying the uncertainty associated with these analyses is necessary to assess temporal changes in soil properties. Forest soil chemical properties, and methods to measure these properties, often differ from agronomic and horticultural soils. Soil proficiency programs do not generally include forest soil samples that are highly acidic, high in extractable Al, low in extractable Ca and often high in carbon. To determine the uncertainty associated with specific analytical methods for forest soils, we collected and distributed samples from two …

Uncertainty Considerations In Calibration And Validation Of Hydrologic And Water Quality Models, J. Hernandez

Civil Engineering Faculty Publications and Presentations

Hydrologic and water quality models (HWQMs) are increasingly used to support decisions on various environmental issues and policy directions for present and future scenarios, at scales varying from watershed to continental levels. Uncertainty associated with such models may affect the ability of the models to accurately evaluate the response of complex systems, leading to misguided assessments and risk management decisions. Current well-known HWQMs contain numerous input parameters, many of which are not known with certainty, and in other cases model users can hardly recognize the genesis of uncertainty. Uncertainty in data, model structure, and model parameters can propagate throughout model …

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 …

Robust Geotechnical Design - Methodology And Applications, Lei Wang

All Dissertations

This dissertation is aimed at developing a novel robust geotechnical design methodology and demonstrating this methodology for the design of geotechnical systems. The goal of a robust design is to make the response of a system insensitive to, or robust against, the variation of uncertain geotechnical parameters (termed noise factors in the context of robust design) by carefully adjusting design parameters (those that can be controlled by the designer such as geometry of the design). Through an extensive investigation, a robust geotechnical design methodology that considers explicitly safety, robustness, and cost is developed. Various robustness measures are considered in this …

Essays On The Quantification And Propagation Of Uncertainty In Climate Change Impact Assessments For Water Resource Systems, Scott Steinschneider

Doctoral Dissertations

Sustainable water resources planning and management under climate change requires a proper treatment of uncertainties that emerge in an impacts analysis. A primary source of this uncertainty originates from the difficulties in projecting how anthropogenic greenhouse gas emissions will evolve over time and influence the climate system at regional and local scales. However, other sources of uncertainty, such as errors in modeling hydrologic response to climate and the influences of internal climate variability, compound the effects of climate change uncertainty and further obscure our understanding of water resources performance under future climate conditions. This work presents an approach to quantify …