Open Access. Powered by Scholars. Published by Universities.®

Civil and Environmental Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Old Dominion University

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 391 - 420 of 540

Full-Text Articles in Civil and Environmental Engineering

The Modified Coastal Storm Impulse Parameter, Sayed Gholamreza Mahmoudpour Apr 2012

The Modified Coastal Storm Impulse Parameter, Sayed Gholamreza Mahmoudpour

Civil & Environmental Engineering Theses & Dissertations

The correlation of the morphological changes to the coast and storm characteristics is among interests of coastal engineers. Better understandings of a storm's potential forces ultimately lead engineers to safer designs and minimize the damages. Therefore, a need to quantify the storm potential forces to a storm parameter is evident. The desired storm parameter is to consider all the relative physical factors and is to present realistic results that then can be proven by actual nature response.

The concept of Coastal Storm Impulse (COSI) parameter was first introduced by Basco and Klentzman (2006) and is based on the conservation of …


Spatial Analysis Of Travel Behavior And Response To Traveler Information, Xin Wang Apr 2012

Spatial Analysis Of Travel Behavior And Response To Traveler Information, Xin Wang

Civil & Environmental Engineering Theses & Dissertations

Transportation planners have long recognized that it is urgent to integrate emerging spatial analysis with travel behavior studies. A clearer understanding of the spatial interactions among travelers and the complex environment they face has the potential to reap benefits of the ongoing technologies of travel behavior, spatial analysis and Advanced Traveler Information Systems (ATIS).

Considering that spatial patterns have been overlooked in the literature of travel behavior and ATIS, the main objective of this research is to use robust methods of spatial analysis to enhance the understanding of how the associations between traveler decisions, built environment and socio-demographic characteristics are …


Static And Impact Load Response Of Reinforced Concrete Beams And Slabs With Nsm-Cfrp Retrofitting, Nakul Ramanna-Sanjeevaiah Apr 2012

Static And Impact Load Response Of Reinforced Concrete Beams And Slabs With Nsm-Cfrp Retrofitting, Nakul Ramanna-Sanjeevaiah

Civil & Environmental Engineering Theses & Dissertations

The use of Near-Surface Mounted Carbon Fiber Reinforced Polymer (NSM-CFRP) reinforcement such as carbon FRP strips holds a high potential for increasing the flexural strength of reinforced concrete members. In comparison to externally bonded CFRP laminates, NSM-CFRP reinforcement approach has several advantages. The main advantages include increased stiffness and strength, better bonding, the possibility of anchoring the reinforcement into adjacent members, and minimal installation time. Thus, the structural engineers worldwide are developing a considerable interest in practical applications of the NSM-CFRP reinforcement technique. A considerable amount of research is still needed in order to fully benefit from this method not …


Analysis Of Primary-Secondary Incident Events On Urban Freeways, Hongbing Zhang Apr 2012

Analysis Of Primary-Secondary Incident Events On Urban Freeways, Hongbing Zhang

Civil & Environmental Engineering Theses & Dissertations

The objective of this study is to understand the nature of primary and secondary traffic incidents, assess their impacts and explore the implications in traffic operations, safety, and planning. To achieve the objective, a queue-based secondary incident identification method was developed and applied based on detailed incident, traffic and geometric data sets from Hampton Roads, Virginia. This identification method can overcome the limitations in earlier studies and identify secondary incidents in both road directions. An innovative event categorization defines the term "primary-secondary incident event", as one characterized by a primary incident and one or more associated secondary incidents in both …


Integrating Probe Vehicles And Stationary Detector Data To Construct Accurate Cumulative Curves To Study Bottlenecks, Khairul Azfi Anuar Apr 2012

Integrating Probe Vehicles And Stationary Detector Data To Construct Accurate Cumulative Curves To Study Bottlenecks, Khairul Azfi Anuar

Civil & Environmental Engineering Theses & Dissertations

Advancements in sensors technologies have given researchers and practitioners access to an immense amount of traffic data from multiple types of sensors. However, because of the diversity of the data types, developing a relationship between the different data sources can be challenging. To further complicate the issue, the presence of error or noise makes it difficult to infer any reliable conclusions from the data. To develop a relationship between different data sources, a new methodology is proposed in this thesis for fusing stationary detector data and probe vehicle data to construct an accurate cumulative curve. To remove or to reduce …


Implementation And Assessment Of A Virtual Reality Experiment In The Undergraduate Themo-Fluids Laboratory, Sushil Chaturvedi, Jaewan Yoon, Rick Mckenzie, Petros J. Katsioloudis, Hector M. Garcia, Shuo Ren Jan 2012

Implementation And Assessment Of A Virtual Reality Experiment In The Undergraduate Themo-Fluids Laboratory, Sushil Chaturvedi, Jaewan Yoon, Rick Mckenzie, Petros J. Katsioloudis, Hector M. Garcia, Shuo Ren

Mechanical & Aerospace Engineering Faculty Publications

Results are presented from an NSF supported project that is geared towards advancing the development and use of virtual reality (VR) laboratories, designed to emulate the learning environment of physical laboratories. As part of this project, an experiment in the undergraduate thermo-fluids laboratory course titled "Jet Impact Force" was transformed into a 3-D virtual reality experiment using the widely used MAYA R and VIRTOOLS R software. In order to facilitate students' interactions with the newly created 3-D interactive, immersive and stereoscopic virtual laboratory environment, the human computer interfaces (HCI) were programmed and incorporated in the simulation software. Two immersion levels …


Project-Risk Management And Decision Analysis In Maritime Maintenance And Repair, Michael C. Plumb, C. Ariel Pinto, Rafael Landaeta, Resit Unal, Thomas Murphy Jan 2012

Project-Risk Management And Decision Analysis In Maritime Maintenance And Repair, Michael C. Plumb, C. Ariel Pinto, Rafael Landaeta, Resit Unal, Thomas Murphy

Engineering Management & Systems Engineering Faculty Publications

The purpose of this paper is to provide insights regarding the implementation of using Project Risk Management (PRM) and Decision Analysis (DA) in managing projects for complex systems such as maritime vessels. The PRM approach apprehends many forms of risk both internal and external within a given project and assists the manager in determining the level of importance of each individual project phase and component to optimize project success. Ship Maintenance and Repair project decision-making requires that risk management and risk analysis techniques be applied in order to guide management in making better decisions to meet ship service life perspective. …


Distribution Analysis Of Freight Transportation With Gravity Model And Genetic Algorithm, Jun Duanmu, Peter Foytik, Asad Khattak, R. Michael Robinson Jan 2012

Distribution Analysis Of Freight Transportation With Gravity Model And Genetic Algorithm, Jun Duanmu, Peter Foytik, Asad Khattak, R. Michael Robinson

VMASC Publications

The application of a gravity model in freight modeling work on both short-haul and long-haul trips is discussed. A commodity-based gravity model was developed to assess the distribution of freight by long-haul trucks in southeastern Virginia. Although gravity models have been used extensively in transportation studies, little work has been done to address the special characteristics of freight transportation, such as the definition of friction factors and the differences between long-haul and short-haul trips. Results of a recent study of these and similar problems provide valuable insight into freight distribution modeling. A new calibration method that used a genetic algorithm …


Impact Of Intercity Tolls In Portugal – An Environmental Perspective, Jorge Bandeira, Margarida Coelho, Miguel Pimentel, Asad Khattak Jan 2012

Impact Of Intercity Tolls In Portugal – An Environmental Perspective, Jorge Bandeira, Margarida Coelho, Miguel Pimentel, Asad Khattak

Civil & Environmental Engineering Faculty Publications

Alternative road pricing schemes are promising strategies to alleviate congestion and other environmental problems related to urban and regional road transportation. However, in practice, environmental issues are not often taken into account, especially at regional level. In 2010, due to the financial crisis in Portugal, several tolls were introduced in some motorways that were previously financed by the government. One of these cases was the A29 motorway, which connects the cities of Aveiro and Oporto. After the introduction of tolls about 50% of the Average Daily Traffic shifted to alternative routes or modes. This paper discusses the impact that tolls …


Identification And Implementation Of Patterns Towards A Model Of Environmental Sustainability, S. Jimmy Gandhi, Santiago Perez, Danial Rushton, Robert Cloutier, Ipek Bozkurt, C. Ariel Pinto Jan 2012

Identification And Implementation Of Patterns Towards A Model Of Environmental Sustainability, S. Jimmy Gandhi, Santiago Perez, Danial Rushton, Robert Cloutier, Ipek Bozkurt, C. Ariel Pinto

Engineering Management & Systems Engineering Faculty Publications

Much like the Quality Revolution did in the 1980's, corporate sustainability has the potential to drive significant changes in the processes and structure of various organizations in the coming decade. With a rapidly growing global population and an ever increasing global demand for resources (Population-Resource-Center, 2012). Sustainability has emerged as one of the primary challenges that organizations will have to deal with in the 21st century. An increasing realization among business executives that profitability by itself is not enough as a measure of success is also driving the increased adoption of sustainable practices in the corporate world (Lowitt and Grimsley, …


On Critical Infrastructure Interdependency, Polinpapilinho F. Katina, C. Ariel Pinto Jan 2012

On Critical Infrastructure Interdependency, Polinpapilinho F. Katina, C. Ariel Pinto

Engineering Management & Systems Engineering Faculty Publications

Developing effective protection, mitigation, and recovery measures for critical infrastructure (CI) systems is paramount in the wake of increasing natural and manmade hazards, risks, and threats. Influencing protection, rescue, and recovery measures are interplays (i.e., interdependencies) among infrastructure systems. Understanding interdependencies plays an essential role in minimizing and reducing cascading failures among complex interdependent infrastructure systems. This paper asserts that deployment of protection, mitigation, and recovery solutions can have little effect on infrastructure management if infrastructure operators and policymakers have partial understanding of infrastructure interdependencies. Using narrative research, authors illustrate that effective coordination and response for protection, mitigation, and recovery …


Green Transportation For A Green Earth, Petros J. Katsioloudis, Mildred V. Jones Jan 2012

Green Transportation For A Green Earth, Petros J. Katsioloudis, Mildred V. Jones

STEMPS Faculty Publications

Transportation is one of the biggest contributors to the destruction of the environment. Results from environmental research and pursuant governmental regulations are changing the way companies do business and how transportation systems address the future. The Environmental Protection Agency (EPA) has been at the forefront in leading environmental research and instituting policies and regulations to fight the issues impacting the environment. The transportation industry and consumers alike are concerned about the environment, energy resources, efficiencies, and economics. In this article, the authors suggest that it is vital that people promote the protection of the environment and strengthen the laws that …


The Reduction Of Storm Surge By Vegetation Canopies: Three-Dimensional Simulations, Y. Peter Sheng, Andrew Lapetina, Gangfeng Ma Jan 2012

The Reduction Of Storm Surge By Vegetation Canopies: Three-Dimensional Simulations, Y. Peter Sheng, Andrew Lapetina, Gangfeng Ma

Civil & Environmental Engineering Faculty Publications

Significant buffering of storm surges by vegetation canopies has been suggested by limited observations and simple numerical studies, particularly following recent Hurricanes Katrina, Rita, and Wilma. Here we simulate storm surge and inundation over idealized topographies using a three-dimensional vegetation-resolving storm surge model coupled to a shallow water wave model and show that a sufficiently wide and tall vegetation canopy reduces inundation on land by 5 to 40 percent, depending upon various storm and canopy parameters. Effectiveness of the vegetation in dissipating storm surge and inundation depends on the intensity and forward speed of the hurricane, as well as the …


Evacuee Route Choice Decisions In A Dynamic Hurricane Evacuation Context, R. Michael Robinson, Asad Khattak Jan 2012

Evacuee Route Choice Decisions In A Dynamic Hurricane Evacuation Context, R. Michael Robinson, Asad Khattak

VMASC Publications

Very high traffic volumes may lead to extensive congestion during hurricane evacuations. Evacuation planners reduce this congestion by careful planning for multiple hurricane scenarios and assignment of evacuation routes and timing. This planning may be for naught if obstructions block key roadways. An advanced traveler information system (ATIS) may be used to guide evacuees to alternate routes, but how effective will that guidance be? Should the use of alternate routes be encouraged? How are drivers likely to respond to delays and information? Will information shorten or improve the reliability of travel times in emergency conditions? Integration of a dynamic evacuation …


Blind Pass Stability Analysis, Robert Burgin Neal Ii Oct 2011

Blind Pass Stability Analysis, Robert Burgin Neal Ii

Civil & Environmental Engineering Theses & Dissertations

The stability of Blind Pass has been subjective since the opening of Redfish Pass in the 1920's. The inlet's stability, defined as its ability to maintain a consistent or equilibrium cross-section, is reviewed in terms of its historic performance and that provided through a 2009 maintenance project. Pre-project expectations are compared with physical results to illustrate the initial success of construction. The Escoffier relationship of tidal prism and cross-section area is implemented to gauge the 2009 projects long term stability. Additional monitoring within one year of construction is analyzed to further realize anticipated stability trends. The hydraulic benefit of a …


Steel Angle Section Members Under Combined Axial Load And Unsymmetric Bending, Maheshchandra Rajasekharan Phanibhushan Jul 2011

Steel Angle Section Members Under Combined Axial Load And Unsymmetric Bending, Maheshchandra Rajasekharan Phanibhushan

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome of an investigation into the experimental and theoretical behavior of steel angle section members under combined axial load and unsymmetric bending. Tests are conducted on a series of six angle section members provided with biaxial pinned-end boundaries about the cross-sectional non-principal axes. The end bending moments and axial load are applied in a quasi-static manner until the member load-carrying capacity is reached. The experimental load-deflection and load-strain curves are recorded. The theoretical analysis is based on a system of both elastic as well as materially nonlinear differential equations. The equations were solved using an iterative …


Solving The Vehicle Re-Identification Problem By Using Neural Networks, Tanweer Rashid Apr 2011

Solving The Vehicle Re-Identification Problem By Using Neural Networks, Tanweer Rashid

Computational Modeling & Simulation Engineering Theses & Dissertations

Vehicle re-identification is the process by which vehicle attributes measured at one point on a road network are compared to vehicle attributes measured at another point in an effort to match vehicles without using any unique identifiers such as license plate numbers. A match is made if the two measurements are estimated to belong to the same vehicle. Vehicle attributes can be sensor readings such as loop induction signatures, or they can also be actual vehicle characteristics such as length, weight, number of axles, etc. This research makes use of vehicle length, travel time, axle spacing and axle weights for …


A Study Of The Correlation Of Sub-Aqueous Beach Profile Change And The Coastal Storm Impulse (Cosi) Parameter, Kevin Bryan Conner Apr 2011

A Study Of The Correlation Of Sub-Aqueous Beach Profile Change And The Coastal Storm Impulse (Cosi) Parameter, Kevin Bryan Conner

Civil & Environmental Engineering Theses & Dissertations

The Coastal Storm Impulse (COSI) parameter is a recently developed storm-strength parameter that was first introduced at the San Diego, California International Conference of Coastal Engineering in 2006 (ICCE) and further examined in 2008 at the ICCE in Hamburg, Germany. This new parameter used the principles of conservation of horizontal momentum to combine storm characteristics such as surge, wave dynamics, currents, and duration into a relative scale used to classify and measure storm response and impacts. The resultant classification system was intended to evaluate potential coastal erosion and the associated loss of coastal infrastructure, as well as provide a storm …


Spatio-Temporal Variations In Soil Moisture And Physicochemical Properties Of A Typical Semiarid Sand-Meadow-Desert Landscape As Influenced By Land Use, L. Duan, T. Liu, X. Wang, G. Wang, L. Ma, Y. Luo Jan 2011

Spatio-Temporal Variations In Soil Moisture And Physicochemical Properties Of A Typical Semiarid Sand-Meadow-Desert Landscape As Influenced By Land Use, L. Duan, T. Liu, X. Wang, G. Wang, L. Ma, Y. Luo

Civil & Environmental Engineering Faculty Publications

A good understanding of the interrelations between land cover alteration and changes in hydrologic conditions (e.g., soil moisture) as well as soil physicochemical properties (e.g., fine soil particles and nutrients) is crucial for maintaining the fragile hydrologic and environmental conditions of semiarid land, such as the Horqin Sandy Land in China, but is lacking in existing literature. The objectives of this study were to examine: (1) spatio-temporal variations of soil moisture and physicochemical properties in semiarid land; and (2) how those variations are influenced by land cover alteration. Using the data collected in a 9.71 km2 well-instrumented area of the …


Towards Reducing Traffic Congestion Using Cooperative Adaptive Cruise Control On A Freeway With A Ramp, George Arnaout, Shannon Bowling Jan 2011

Towards Reducing Traffic Congestion Using Cooperative Adaptive Cruise Control On A Freeway With A Ramp, George Arnaout, Shannon Bowling

Engineering Management & Systems Engineering Faculty Publications

Purpose: In this paper, the impact of Cooperative Adaptive Cruise Control (CACC) systems on traffic performance is examined using microscopic agent-based simulation. Using a developed traffic simulation model of a freeway with an on-ramp - created to induce perturbations and to trigger stop-and-go traffic, the CACC system’s effect on the traffic performance is studied. The previously proposed traffic simulation model is extended and validated. By embedding CACC vehicles in different penetration levels, the results show significance and indicate the potential of CACC systems to improve traffic characteristics and therefore can be used to reduce traffic congestion. The study shows that …


Selection Of Source And Use Of Traffic Information In Emergency Situations, R. Michael Robinson, Asad Khattak Jan 2011

Selection Of Source And Use Of Traffic Information In Emergency Situations, R. Michael Robinson, Asad Khattak

VMASC Publications

The access and the use of advanced traveler information systems (ATISs) by drivers during normal commuting have been extensively assessed and analyzed. Emergency managers and transportation officials have extended the results of studies of ATIS use under routine conditions to emergency scenarios under the assumption that drivers' responses to information under emergency conditions mimic those seen under normal driving conditions. A recent survey of potential hurricane evacuees suggests the need to revisit this assumption. Results indicate that although commercial radio reports and variable message signs continue to be the sources of traffic information cited the most frequently, other information sources …


Parallel-Sparse Symmetrical/Unsymmetrical Finite Element Domain Decomposition Solver With Multi-Point Constraints For Structural/Acoustic Analysis, Siroj Tungkahotara, Willie R. Watson, Duc T. Nguyen, Subramaniam D. Rajan Jan 2011

Parallel-Sparse Symmetrical/Unsymmetrical Finite Element Domain Decomposition Solver With Multi-Point Constraints For Structural/Acoustic Analysis, Siroj Tungkahotara, Willie R. Watson, Duc T. Nguyen, Subramaniam D. Rajan

Civil & Environmental Engineering Faculty Publications

Details of parallel-sparse Domain Decomposition (DD) with multi-point constraints (MPC) formulation are explained. Major computational components of the DD formulation are identified. Critical roles of parallel (direct) sparse and iterative solvers with MPC are discussed within the framework of DD formulation. Both symmetrical and unsymmetrical system of simultaneous linear equations (SLE) can be handled by the developed DD formulation. For symmetrical SLE, option for imposing MPC equations is also provided.

Large-scale (up to 25 million unknowns involving complex numbers) structural and acoustic Finite Element (FE) analysis are used to evaluate the parallel computational performance of the proposed DD implementation using …


Primary And Secondary Incident Management: Predicting Durations In Real Time, Asad J. Khattak, Xin Wang, Hongbing Zhang, Mecit Cetin Jan 2011

Primary And Secondary Incident Management: Predicting Durations In Real Time, Asad J. Khattak, Xin Wang, Hongbing Zhang, Mecit Cetin

Civil & Environmental Engineering Faculty Publications

Traffic incidents are a major source of congestion in Virginia. Secondary incidents comprise a relatively small but important portion of all incidents, and relatively little is known about their occurrence, characteristics, and associated delays. The main objectives of this study were to define secondary incidents, understand and analyze the occurrence and nature of such incidents, and develop tools that can comprehensively and continuously analyze primary and secondary incidents at the planning and operational levels, ultimately contributing to congestion management. The scope of the study is limited to freeway incidents in the Hampton Roads (HR) area. The study found that secondary …


Vehicular Ad Hoc Networks, Syed R. Rizvi, Stephan Olariu, Christina M. Oinotti, Shaharuddin Salleh, Mona E. Rizvi, Zainab Zaidi Jan 2011

Vehicular Ad Hoc Networks, Syed R. Rizvi, Stephan Olariu, Christina M. Oinotti, Shaharuddin Salleh, Mona E. Rizvi, Zainab Zaidi

Computer Science Faculty Publications

(First paragraph) Vehicular ad hoc networks (VANETs) have recently been proposed as one of the promising ad hoc networking techniques that can provide both drivers and passengers with a safe and enjoyable driving experience. VANETs can be used for many applications with vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. In the United States, motor vehicle traffic crashes are the leading cause of death for all motorists between two and thirty-four years of age. In 2009, the National Highway Traffic Safety Administration (NHTSA) reported that 33,808 people were killed in motor vehicle traffic crashes. The US Department of Transportation (US-DOT) estimates that …


Plain And Steel-Reinforced Concrete Shear Walls With And Without Cfrp Retrofitting, Ali Mohammed Salih Al Aloosi Oct 2010

Plain And Steel-Reinforced Concrete Shear Walls With And Without Cfrp Retrofitting, Ali Mohammed Salih Al Aloosi

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome- of a study of the behavior and strength of plain and steel-reinforced concrete shear walls with and without a window opening and Carbon Fiber-Reinforced Polymer (CFRP) retrofitting. A total of seven tests were conducted using six different shear walls. Each wall was subjected to a gradually increasing static load at one of it's top corners until the maximum load was reached. The load-deflection relations and the walls' failure patterns were observed and recorded. It was found that the window opening in the plain concrete wall reduced the wall load capacity by 18 percent. For the …


Application Of The Coastal Storm Impulse (Cosi) Parameter To Predict Coastal Erosion, Robert Aaron Walker Oct 2010

Application Of The Coastal Storm Impulse (Cosi) Parameter To Predict Coastal Erosion, Robert Aaron Walker

Civil & Environmental Engineering Theses & Dissertations

A new coastal storm-strength parameter, the Coastal Storm Impulse (COSI) parameter, was introduced at the 2006 International Conference of Coastal Engineering (ICCE) in San Diego and further discussed at the ICCE 2008 in Hamburg. COSI is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. Both tropical storms (hurricanes) and extra-tropical storms (northeasters) can produce similar COSI parameters. Potential implications of such a storm classification system include the evaluation of potential coastal erosion and coastal infrastructure, as well as providing a universal storm strength indicator that is directly tied …


Analysis Of Fema Guidelines For Coastal Dunes Using A Numerical Model, Brenton Edward Payne Oct 2010

Analysis Of Fema Guidelines For Coastal Dunes Using A Numerical Model, Brenton Edward Payne

Civil & Environmental Engineering Theses & Dissertations

FEMA's current guideline for coastal dune erosion is called the 540 Rule. The intent of the 540 Rule is to act as a boolean guideline for dune protection. If a dune is validated as being substantial against the 1 % Annual Chance Storm Water Elevation Level by the 540 Rule, then the area behind the dune is considered to be susceptible to less energetic flooding. This is known as an AE Flood Zone. An immediate effect of being rezoned is a significant drop in the insurance costs behind the dune. However, if the dune is not validated by the 540 …


Using Micro-Simulation To Evaluate Transit Signal Priority For Lrt Operations In A Downtown Environment, Faisal Mahmud Jul 2010

Using Micro-Simulation To Evaluate Transit Signal Priority For Lrt Operations In A Downtown Environment, Faisal Mahmud

Civil & Environmental Engineering Theses & Dissertations

Transit Signal Priority or TSP is an operational strategy that facilitates the movement of transit vehicles such as buses, light rail or streetcars, through traffic-signal controlled intersections. The benefits of TSP operations include improved schedule adherence and improved transit travel times with minimal impact to normal traffic operations. New advances in Global Positioning Systems, detection and communication, and control strategies have helped overcome many problems with early systems and increased interest in implementing TSP for Light Rail Transit (LRT) and other transit operations. The increased capabilities of these advanced systems have led to a dramatic increase in operational and planned …


A Study Of Passive Earth Pressure In Anisotropic Sand With Various Wall Movement Modes, Achmad Bakri Muhiddin Jul 2010

A Study Of Passive Earth Pressure In Anisotropic Sand With Various Wall Movement Modes, Achmad Bakri Muhiddin

Civil & Environmental Engineering Theses & Dissertations

This study investigated the effect of anisotropy on passive pressure in sands by developing computer simulation utilizing FLAC code for plane strain condition. A series of wall movement modes was applied namely translation, rotation about a point below the wall, RBT, and rotation about a point above the wall, RTT.

From comparisons with other FLAC model in translation mode with isotropic material, the coefficients of passive pressure Kp were similar to each other except for some combinations of zero dilation, low wall friction, and high angle of internal friction ϕ. Dilation angle has less effect on Kp than …


The Influence Of Mechanical Circulation On Water Column Stability And Dissolved Oxygen In Stratified Lakes, Paal Engebrigtsen Apr 2010

The Influence Of Mechanical Circulation On Water Column Stability And Dissolved Oxygen In Stratified Lakes, Paal Engebrigtsen

Civil & Environmental Engineering Theses & Dissertations

Surface circulators have been used in wastewater and industrial lagoons for many years, but only recently have they been designed for lakes and reservoirs as a water quality management tool. Their relatively low capital investment and operational costs make them an attractive chemical free option for ameliorating the symptoms of eutrophication. Little research has been conducted on their effectiveness in impacting water quality. Today many lake managers are waiting for independent research on surface circulators' performance before installing such systems.

The Occoquan Reservoir was the primary site for a study conducted to examine the influence of surface circulation on water …