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Full-Text Articles in Civil Engineering

Estimating Field At-Rest Lateral Stress Coefficient And Liquefaction Resistance Of Aged Sands, Md Hossian Dec 2014

Estimating Field At-Rest Lateral Stress Coefficient And Liquefaction Resistance Of Aged Sands, Md Hossian

All Dissertations

Published results of laboratory tests to evaluate the influence of the at-rest lateral stress coefficient (K0) and the overconsoildation ratio (OCR) on liquefaction resistance of sands are reviewed in this dissertation. It is found that significant increase in liquefaction resistance can occur with high K0 and/or high OCR. A unique relationship between liquefaction resistance of isotropic and anisotropic normally consolidated sands exists based on the published laboratory data. Relationships between liquefaction resistance of overconsolidated sands and normally consolidated sands also have been shown in previous laboratory studies. Based on the previous studies, expressions for K0 and OCR correction factors (KK0 …


Robust Design Of Shield Tunnels ‒ Considering The Longitudinal Variation Of Input Parameters, Wenping Gong Dec 2014

Robust Design Of Shield Tunnels ‒ Considering The Longitudinal Variation Of Input Parameters, Wenping Gong

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This dissertation, aimed at developing an improved design methodology for shield tunnels that explicitly considers design robustness against longitudinal variation of input parameters (such as soil parameters). To this end, a new solution model for shield tunnel performance analysis was first developed. In this new model, the random field concept was employed to model the longitudinal variation of input parameters. The input parameters (in the longitudinal domain) that had been generated with Monte Carlo simulation (MCS) were used as inputs for the tunnel longitudinal behavior analysis. Here, the finite element method (FEM) based upon Winkler elastic foundation theory was employed. …


Robust Geotechnical Design - Methodology And Applications, Lei Wang Dec 2014

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 …


Modeling Sustainability In Renewable Energy Supply Chain Systems, Fei Xie Dec 2014

Modeling Sustainability In Renewable Energy Supply Chain Systems, Fei Xie

All Dissertations

This dissertation aims at modeling sustainability of renewable fuel supply chain systems against emerging challenges. In particular, the dissertation focuses on the biofuel supply chain system design, and manages to develop advanced modeling framework and corresponding solution methods in tackling challenges in sustaining biofuel supply chain systems. These challenges include: (1) to integrate 'environmental thinking' into the long-term biofuel supply chain planning; (2) to adopt multimodal transportation to mitigate seasonality in biofuel supply chain operations; (3) to provide strategies in hedging against uncertainty from conversion technology; and (4) to develop methodologies in long-term sequential planning of the biofuel supply chain …


Projections Of Future Us Design Wind Speeds Due To Climate Change For Estimating Hurricane Losses, Fangqian Liu Aug 2014

Projections Of Future Us Design Wind Speeds Due To Climate Change For Estimating Hurricane Losses, Fangqian Liu

All Dissertations

Hurricane is among the most dangerous and costliest natural hazards that affect the coastal environment of the United States (U.S.) every year. Hurricane activities have been observed to change in many aspects since the last century including the changes in both intensity and annual storm frequency. The extent to which aspect of climate change contributes to the variation in hurricane activities from long-term historical statistics is still not clearly understood at this point. This study examines the impacts of two climate change effects (change in annual storm frequency and sea surface temperature) on future U.S. design wind speeds for the …


Building Envelope Failure Assessment Of Residential Developments Subjected To Hurricane Wind Hazards, James Grayson Aug 2014

Building Envelope Failure Assessment Of Residential Developments Subjected To Hurricane Wind Hazards, James Grayson

All Dissertations

An unfortunate global precedent has been set by hurricane wind hazard events that illustrate the importance of building resilient coastal communities. Although community resilience is heavily dependent upon the socioeconomic response of the community before, during, and after a hazard event, it is also dependent on the vulnerability of the community to a disaster. Therefore, one way that structural engineers can assist communities in becoming more resilient is to investigate and implement methods that mitigate the 'initial shock' experienced by a residential development subjected to a hazard event. The focus of this research was to develop a mechanics-based building envelope …


Fluid Mud Gravity Currents Through Emergent Aquatic Vegetation, Nazli Yilmaz Aug 2014

Fluid Mud Gravity Currents Through Emergent Aquatic Vegetation, Nazli Yilmaz

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In this theoretical and experimental investigation, the propagation dynamics of the fluid-mud underflows form in pipeline dredge disposal operations in the designated areas are studied. These areas such as wetlands, nearshore waters are typically covered with stiff, cylindrical, emergent aquatic vegetation. The main goals of this study are to propose mathematical formulations for the bottom shear force and drag force of emergent stiff aquatic vegetation acting on the gravity current, and to present novel propagation modeling approaches. To be able to predict these forces, a friction coefficient (for the bottom shear force), and a drag coefficient (for vegetation skin friction …


Numerical Investigation Of One-Dimensional Shallow Water Flow And Sediment Transport Model Using Discontinouous Galerkin Method, Farzam Safarzadeh Maleki May 2014

Numerical Investigation Of One-Dimensional Shallow Water Flow And Sediment Transport Model Using Discontinouous Galerkin Method, Farzam Safarzadeh Maleki

All Dissertations

A one-dimensional shallow water flow and sediment transport model is developed using a discontinuous Galerkin finite element scheme. As a first step, four different time marching schemes as well as three different slope limiters have been investigated to find the optimum modeling combination. The efficiency and accuracy of the time marching schemes and slope limiters are quantitatively examined using CPU runtime and comparison between the simulated results and theoretical/experimental data. It is found that using the second order Adam-Bashforth time marching scheme and Monotonized Central method leads to most efficient and accurate results. As the second part of this research, …


Minimizing Bridge And Pavement Deterioration From Large Trucks: A Policy Analysis For Damage Recovery, Kakan Dey May 2014

Minimizing Bridge And Pavement Deterioration From Large Trucks: A Policy Analysis For Damage Recovery, Kakan Dey

All Dissertations

Facing an exceptional challenge of maintaining state roadways with ever-shrinking financial resources, this research examined multiple facets of the impact of overweight trucks. The objectives of this research were to investigate the impact of overweight trucks on pavements and bridges, and develop policy recommendations based on technical analysis and the modern political and institutional environment in South Carolina. To achieve the objectives, this research modeled pavement and bridge deterioration, investigated the adequacy of standard practices in state agencies, examined how trucking industry perceives those practices, and developed policy analysis models. Pavement and bridge deterioration analysis revealed that pavement and bridge …


The Development Of Empirical Models To Evaluate Energy Use And Energy Cost In Wastewater Collection, David Young May 2014

The Development Of Empirical Models To Evaluate Energy Use And Energy Cost In Wastewater Collection, David Young

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This research introduces a unique data analysis method and develops empirical models to evaluate energy use and energy cost in wastewater collection systems using operational variables. From these models, several Best Management Processes (BMPs) are identified that should benefit utilities and positively impact the operation of existing infrastructure as well as the design of new infrastructure. Further, the conclusions generated herein display high transferability to certain manufacturing processes. Therefore, it is anticipated that these findings will also benefit pumping applications outside of the water sector. Wastewater treatment is often the single largest expense at the local government level. Not surprisingly, …