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Articles 991 - 1020 of 1183

Full-Text Articles in Civil and Environmental Engineering

Isogeometric Finite Element Analysis Using T-Splines, Jingang Li Aug 2009

Isogeometric Finite Element Analysis Using T-Splines, Jingang Li

Theses and Dissertations

Non-uniform rational B-splines (NURBS) methodology is presented, on which the isogeometric analysis is based. T-splines are also introduced as a surface design methodology, which are a generalization of NURBS and permit local refinement. Isogeometric analysis using NURBS and T-splines are applied separately to a structural mechanics problem. The results are compared with the closed-form solution. The desirable performance of isogeometric analysis using T-splines on engineering analysis is demonstrated.

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Analysis Of The Sediment Transport Capabilities Of Tuflow, Cameron G. Jenkins Aug 2009

Analysis Of The Sediment Transport Capabilities Of Tuflow, Cameron G. Jenkins

Theses and Dissertations

The need to know how river morphology changes due to sedimentation is increasingly important as we attempt to predict future events. Engineers use numeric models to predict effects of changed morphology on river systems. The numerical model Two-dimensional Unsteady Flow (TUFLOW) has recently added, and is continually improving, its capability to model sediment transport in rivers and coastal systems. This paper evaluates the new tools for modeling sediment transport presently contained within TUFLOW and compares these tools with analytical and laboratory case studies. Currently TUFLOW simulates combined bed and suspended load transport of noncohesive sediments under the effect of currents …

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Liquefaction Mitigation In Silty Sands Using Stone Columns With Wick Drains, Michael James Quimby Aug 2009

Liquefaction Mitigation In Silty Sands Using Stone Columns With Wick Drains, Michael James Quimby

Theses and Dissertations

Stone column treatment is commonly used to mitigate liquefaction hazard in sandy soils. Research and experience indicate that this method is effective for clean sands but that it may not be effective for silts and sands with fines contents greater than 15-20%. An alternative to the stone column method involves supplementing stone column treatment with pre-fabricated vertical wick drains installed prior to the stone columns installation. Although this method is used in practice, there has not been a formal academic study of its effectiveness. This thesis evaluates seven different case histories where wick drains were used and one where wick …

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Active Human Power Generation: As A New Portion Of The Energy Supply, Robert J. Mccleary Ii Aug 2009

Active Human Power Generation: As A New Portion Of The Energy Supply, Robert J. Mccleary Ii

Library Research Grants

The discovery and use of energy has revolutionized society for more then two hundred years. With it we have witnessed an explosion of knowledge and technology unparallel in history. Unfortunately our main sources of energy are in limited supply. In order to continue to enjoy the progress made during these last few centuries it is necessary to know both when our supply will run out and to find alternative sources.

The question of when the fossil fuels will run out has been on the minds of many scientists for more than fifty years. In 1956 Dr. M. King Hubbert developed …

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Visualizing And Modeling Mining-Induced Surface Subsidence, Marcor Gibbons Platt Jul 2009

Visualizing And Modeling Mining-Induced Surface Subsidence, Marcor Gibbons Platt

Theses and Dissertations

Ground subsidence due to underground coal mining is a complex, narrowly-understood phenomenon. Due to the complicated physical processes involved and the lack of a complete knowledge of the characteristics of overlying strata, the reliability of current prediction techniques varies widely. Furthermore, the accuracy of any given prediction technique is largely dependent upon the accuracy of field measurements and surveys which provide input data for the technique. A valuable resource available for predicting and modeling subsidence is aerial survey technology. This technology produces yearly datasets with a high density of survey points. The following study introduces a method wherein these survey …

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Optimized Distribution Of Strength In Buckling-Restrained Brace Frames In Tall Buildings, Graham Thomas Oxborrow Jul 2009

Optimized Distribution Of Strength In Buckling-Restrained Brace Frames In Tall Buildings, Graham Thomas Oxborrow

Theses and Dissertations

Nonlinear time history analysis is increasingly being used in the design of tall steel structures, but member sizes still must be determined by a designer before an analysis can be performed. Often the distribution of story strength is still based on an assumed first mode response as determined from the Equivalent Lateral Force (ELF) procedure. For tall buckling restrained braced frames (BRBFs), two questions remain unanswered: what brace distribution will minimize total brace area, while satisfying story drift and ductility limits, and is the ELF procedure an effective approximation of that distribution? In order to investigate these issues, an optimization …

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Slip Lined Culvert Retrofit And Fish Passage, Joseph Ray Webb Jun 2009

Slip Lined Culvert Retrofit And Fish Passage, Joseph Ray Webb

Theses and Dissertations

Culverts throughout the country are approaching or are past their original design lives. These ‘baby boomer’ culverts will need to be repaired, rehabilitated, or replaced. Because entire culvert replacement is so expensive and intrusive, alternate measures to extend the culvert project life are growing increasingly popular. One such method is slip lining, where a ‘sleeve’ is installed within an existing culvert barrel and stabilized. Plastic pipe sleeves are very popular for slip lining primarily because the plastic material's lower Manning's roughness values allow for the culvert capacity to be maintained despite a reduction in culvert size. Unfortunately, the reduced friction …

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Automated All-Quadrilateral Mesh Adaptation Through Refinement And Coarsening, Bret D. Anderson Jun 2009

Automated All-Quadrilateral Mesh Adaptation Through Refinement And Coarsening, Bret D. Anderson

Theses and Dissertations

This thesis presents a new approach to conformal all-quadrilateral mesh adaptation. In finite element modeling applications, it is often desirable to modify the node density of the mesh; increasing the density in some parts of the mesh to provide more accurate results, while decreasing the density in other parts to reduce computation time. The desired node density is typically determined by a sizing function based on either the geometry of the model or the results of a finite element solution. Although there are numerous mesh adaptation methods currently in use, including initial adaptive mesh generation, node redistribution, and adaptive mesh …

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Economic Development Criteria And Project Prioritization, Jason Scott Mcgee May 2009

Economic Development Criteria And Project Prioritization, Jason Scott Mcgee

Theses and Dissertations

To provide a more in-depth analysis of potential roadway projects, the Utah Department of Transportation (UDOT) desired a method of evaluating projects according to their economic potential without using potentially costly computer models or excessive data collection. Brigham Young University (BYU) was retained to research and recommend criteria for the economic development criteria in the project-prioritization process. A literature review was first undertaken to better understand the transportation-economic development relationship. Using the literature review, combined with the information from the Economic Development Corporation of Utah, the Governor's Office of Planning and Budget, the Governor's Office of Economic Development, and a …

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Evaluation Of Full-Depth Reclamation On Strength And Durability Of Pavement Base Layers, Benjamin Earl Griggs Mar 2009

Evaluation Of Full-Depth Reclamation On Strength And Durability Of Pavement Base Layers, Benjamin Earl Griggs

Theses and Dissertations

The purpose of this research was to determine the effect of full-depth reclamation (FDR) on the strength and durability of aggregate base layers in a coordinated approach involving both field and laboratory testing. Field comparisons between the pre-reclamation neat base and post-reclamation blended base were supplemented with laboratory experiments conducted to determine the effects of reclaimed asphalt pavement (RAP) content, compaction effort, and heating on the strength and durability of roadways reconstructed using FDR with a portable asphalt recycling machine (PARM). Also, the effect of reclamation on the spatial uniformity of the pavement structures was explored by comparing variability in …

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The Utilization Of Light Gauge Steel In Residential Construction On The State Of Utah, Matthew Zaugg Perkins Mar 2009

The Utilization Of Light Gauge Steel In Residential Construction On The State Of Utah, Matthew Zaugg Perkins

Theses and Dissertations

This thesis researched why light gauge steel framing members are not used more in single-family residential construction. A survey was designed to extract information from licensed contractors in Utah on uses of light gauge steel framing members in residential homes. The purpose of the research was to discover what Utah builder's perception was concerning light gauge steel framing. Also, the researcher tried to learn a little about the contractors to see if there was a correlation between contractors that used light gauge steel and those that did not. Names of licensed general building contractors and residential contractors and their contact …

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Second-Order Structural Analysis With One Element Per Member, Jesse William Lyon Mar 2009

Second-Order Structural Analysis With One Element Per Member, Jesse William Lyon

Theses and Dissertations

In this thesis, formulas for the local tangent stiffness matrix of a plane frame member are derived by differentiating the member resistance vector in the displaced position. This approach facilitates an analysis using only one element per member. The formulas are checked by finite difference. The derivation leads to the familiar elastic and geometric stiffness matrices used by other authors plus an additional higher order geometric stiffness matrix. Contributions of each of the three sub-matrices to the tangent stiffness matrix are studied on both the member and structure levels through two numerical examples. These same examples are analyzed three different …

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Phosphorus Fractionation And Distribution Across Delta Of Deer Creek Reservoir, Warren C. Casbeer Mar 2009

Phosphorus Fractionation And Distribution Across Delta Of Deer Creek Reservoir, Warren C. Casbeer

Theses and Dissertations

Eutrophication of reservoir systems, which causes deterioration of water quality through increased algal growth, is detrimental to our sustainable water supply and additionally impairs other beneficial reservoir uses. Limiting the amount of phosphorus (P) entering the system has been the key management tool for this problem, as P is the main limiting nutrient for plant and algal growth. These efforts have focused on controlling input of P from point sources, such as effluents from wastewater treatment plants, dairies, and industrial factories. Even in systems (such as reservoirs) with significantly reduced external P loading, however, there has been continued eutrophication and …

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Behavior Of A Full-Scale Pile Cap With Loosely And Densely Compacted Clean Sand Backfill Under Cyclic And Dynamic Loadings, Colin Reuben Cummins Mar 2009

Behavior Of A Full-Scale Pile Cap With Loosely And Densely Compacted Clean Sand Backfill Under Cyclic And Dynamic Loadings, Colin Reuben Cummins

Theses and Dissertations

A series of lateral load tests were performed on a full-scale pile cap with three different backfill conditions, namely: with no backfill present, with densely compacted clean sand in place, and with loosely compacted clean sand in place. In addition to being displaced under a static loading, the pile cap was subjected to low frequency, small displacement loading cycles from load actuators and higher frequency, small displacement, dynamic loading cycles from an eccentric mass shaker. The passive earth pressure from the backfill was found to significantly increase the load capacity of the pile cap. At a displacement of about 46 …

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Correlating Responses Of Portable Field Instruments Used For Testing Aggregate And Soil Pavement Layers, Wendy Melissa Thompson Mar 2009

Correlating Responses Of Portable Field Instruments Used For Testing Aggregate And Soil Pavement Layers, Wendy Melissa Thompson

Theses and Dissertations

This research examined correlations among the responses of five portable aggregate and soil testing devices, including the nuclear density gauge (NDG), dynamic cone penetrometer (DCP), heavy Clegg impact soil tester (CIST), soil stiffness gauge (SSG), and portable falling-weight deflectometer (PFWD). Readings were analyzed from 41 project sites on treated and untreated base, subbase, and subgrade layers representing 15 different material types in Iowa, Louisiana, Utah, and Wyoming. Analyses of the data revealed statistically significant correlations for all six of the possible two-way comparisons involving the DCP, CIST, SSG, and PFWD, and a nomograph was developed for correlating responses among these …

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Stochastic Spatio-Temporal Uncertainty In Gis-Based Water Quality Modeling Of The Land Water Interface, Ahmad Mohamad Salah Feb 2009

Stochastic Spatio-Temporal Uncertainty In Gis-Based Water Quality Modeling Of The Land Water Interface, Ahmad Mohamad Salah

Theses and Dissertations

Integrated water resources management has been used for decades in various formats. The limited resources and the ever growing population keep imposing pressure on decision makers to better-, and reliably, manage the available waters. On the other hand, the continuous development in computing and modeling power has helped modelers and decision makers considerably. To use these models, assumptions have to be made to fill in the gaps of missing data and to approximate the current conditions. The type and amount of information available can also be used to help select the best model from the currently available models. Advances in …

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Assessing Water Quality Modeling In Subtropical Regions Based On A Case Study Of The Aguamilpa Reservoir, Oliver Obregon Dec 2008

Assessing Water Quality Modeling In Subtropical Regions Based On A Case Study Of The Aguamilpa Reservoir, Oliver Obregon

Theses and Dissertations

The shortage of water in Mexico has made public and private institutions look at reservoirs as an alternative solution for present and future water supply. However, eighty percent of the existing reservoirs in Mexico are contaminated at some level, many severely. Water quality models are water-management tools used to diagnose water quality problems and the impact of various environmental conditions. They can be effective in assessing various measures of remediation leading to improved water quality. In most of the cases such water quality models have been successfully applied in reservoirs located in temperate climates. However, the use of water quality …

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Theoretical Determination Of Subcritical Sequent Depths For Complete And Incomplete Hydraulic Jumps In Closed Conduits Of Any Shape, Nathan John Lowe Dec 2008

Theoretical Determination Of Subcritical Sequent Depths For Complete And Incomplete Hydraulic Jumps In Closed Conduits Of Any Shape, Nathan John Lowe

Theses and Dissertations

In order to predict hydraulic jump characteristics for channel design, the jump height may be determined by calculating the subcritical sequent depth from momentum theory. In closed conduits, however, outlet submergence may fill the conduit entirely before the expected sequent depth is reached. This is called an incomplete or pressure jump (as opposed to a complete or free-surface jump), because pressure flow conditions prevail downstream. Since the momentum equation involves terms for the top width, area, and centroid of flow, the subcritical sequent depth is a function of the conduit shape in addition to the upstream depth and Froude number. …

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Crashes In The Vicinity Of Major Crossroads, Charles G. Allen Nov 2008

Crashes In The Vicinity Of Major Crossroads, Charles G. Allen

Theses and Dissertations

Major crossroads are designed to facilitate the conflicting movements of numerous vehicles in a manner that is both safe and efficient. Accesses located within the functional areas of major crossroads add complication to intersection activity due to additional conflicts arising from ingressing and egressing movements at the accesses. In this research, the impact of accesses on crashes within major crossroad functional areas was analyzed. Specifically, the effects of access spacing within functional areas and access setback from intersections were addressed. In order to conduct the analysis, the functional areas of 159 signalized major arterial crossroads across the state of Utah …

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Foundational Data Repository For Numeric Engine Validation, Jason Michael Hollingsworth Nov 2008

Foundational Data Repository For Numeric Engine Validation, Jason Michael Hollingsworth

Theses and Dissertations

Many different numeric models have been created to address a variety of hydraulic and hydrologic engineering applications. Each utilizes formulations and numeric methods to represent processes such as contaminant transport, coastal circulation, and watershed runoff. Although one process may be adequately represented by a model, this does not guarantee that another process will be represented even if that process is similar. For example, a model that computes subcritical flow does not necessarily compute supercritical flow. Selecting an appropriate numeric model for a situation is a prerequisite to obtaining accurate results. Current policies and resources do not provide adequate guidance in …

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Effect Of Initial Scarification And Overlay Treatment Timing On Chloride Concentrations In Concrete Bridge Decks, Curtis Daniel Nolan Nov 2008

Effect Of Initial Scarification And Overlay Treatment Timing On Chloride Concentrations In Concrete Bridge Decks, Curtis Daniel Nolan

Theses and Dissertations

Considering the pervasive presence of chlorides in concrete bridge decks, bridge engineers have a critical responsibility to perform proper and effective preventive maintenance and rehabilitation operations. Bridge engineers often perform scarification and overlay (SO) procedures on concrete bridge decks to minimize the corrosion of reinforcing steel due to chloride ingress. Given the need to develop guidelines for the initial timing of SO treatments, the specific objectives of this research were to collect information from several department of transportation (DOT) personnel about their SO procedures and, subsequently, to determine the recommended timing of initial SO procedures on concrete bridge decks for …

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Median Crossover Crashes In The Vicinity Of Interchanges On Utah Interstates, Katherine Elaine Winters Nov 2008

Median Crossover Crashes In The Vicinity Of Interchanges On Utah Interstates, Katherine Elaine Winters

Theses and Dissertations

While not accounting for a significant proportion of overall crashes, median crossover crashes in the state of Utah do account for a significant proportion of interstate fatalities. Due to the seriousness of median crossover crashes in the state of Utah, the need exists to evaluate the impact of median crossover crashes in the state, to identify locations where median crossover crashes may be occurring at particularly high rates, and to identify methods to help mitigate these crashes. Previous research has noted that median crossover crash rates appear to increase in the vicinity of interchanges. The purpose of this research, therefore, …

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Pile Downdrag During Construction Of Two Bridge Abutments, Brian Keith Sears Oct 2008

Pile Downdrag During Construction Of Two Bridge Abutments, Brian Keith Sears

Theses and Dissertations

Two steel pipe piles in place in abutments for two different bridge constructions sites were instrumented with strain gauges to measure the magnitude of negative skin friction. The piles were monitored before, during and up to 19 months after construction was completed. The load versus depth and time in each pile is discussed. Maximum observed dragloads ranged from 98 to 127 kips. A comparison with two methods for calculating dragloads is presented. Both comparison methods were found to be conservative, with the Briaud and Tucker (1997) approach more closely estimating the observed load versus depth behavior.

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Effects Of Environmental Factors On Construction Of Soil-Cement Pavement Layers, John E. Michener Sep 2008

Effects Of Environmental Factors On Construction Of Soil-Cement Pavement Layers, John E. Michener

Theses and Dissertations

The specific objectives of this research were to quantify the effects of certain environmental factors on the relative strength loss of soil-cement subjected to compaction delay and to develop a numerical tool that can be easily used by engineers and contractors for determining a maximum compaction delay time for a given project. These objectives were addressed through extensive laboratory work and statistical analyses. The laboratory work involved testing an aggregate base material and a subgrade soil, each treated with two levels of cement. Environmental factors included in the experimentation were wind speed, temperature, and relative humidity, and three levels of …

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Fish Passage At Udot Culverts: Prioritization And Assessment, Aaron Evens Beavers Jul 2008

Fish Passage At Udot Culverts: Prioritization And Assessment, Aaron Evens Beavers

Theses and Dissertations

State Departments of Transportation are becoming more involved in providing Aquatic Organism Passage (AOP) at road-stream crossings. Department of Transportation (DOT) emphasis on AOP has been driven largely in response to endangered species listings, other agencies' initiatives, and the desire to restore ecosystem connectivity to watercourses. UDOT is currently responsible for approximately 47,000 culverts, but AOP is currently addressed only on an as-needed basis. Currently UDOT has no prioritization or assessment strategy procedure for AOP at UDOT road-stream crossings. Historical fish passage strategies have focused on federally listed adult anadromous salmon and trout. These are generally very large fish whose …

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Localized Coarsening Of Conforming All-Hexahedral Meshes, Adam C. Woodbury Jul 2008

Localized Coarsening Of Conforming All-Hexahedral Meshes, Adam C. Woodbury

Theses and Dissertations

Finite element mesh adaptation methods can be used to improve the efficiency and accuracy of solutions to computational modeling problems. For many finite element modeling applications, a conforming all-hexahedral mesh is preferred. When adapting a hexahedral mesh, localized modifications that preserve topologic conformity are often desired. Effective hexahedral refinement methods that satisfy these criteria have recently become available. However, due to hexahedral mesh topology constraints, little progress has been made in the area of hexahedral coarsening. This thesis presents a new method to locally coarsen conforming all-hexahedral meshes. The method works on both structured and unstructured meshes and is not …

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Quantitative Uncertainty Of Chemical Plume Transport In Low Wind Speeds Using Measured Field Data And Stochastic Modeling, Veronica Elaine Wannberg Jul 2008

Quantitative Uncertainty Of Chemical Plume Transport In Low Wind Speeds Using Measured Field Data And Stochastic Modeling, Veronica Elaine Wannberg

Theses and Dissertations

Low wind speed conditions should be studied because these conditions can present risk, particularly for areas immediately surrounding the release point, where high concentrations can occur and not dissipate. The following research attempts to clarify the processes governing both the general and low wind speed cases by determining the accuracy and uncertainty of standard prediction methods for contaminant plume transport in low wind speed plume modeling. Multiple techniques were utilized to incorporate field measured data, previously gathered for a different purpose, to generate parameter distributions and ground-truth data that could be used in stochastic models for chemical plume prediction. These …

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Ability Of Adv Measurements To Detect Turbulence Differences Between Angular And Rounded Gravel Beds Of Intermediate - Roughness Scale, Benjamin B. Haws Jul 2008

Ability Of Adv Measurements To Detect Turbulence Differences Between Angular And Rounded Gravel Beds Of Intermediate - Roughness Scale, Benjamin B. Haws

Theses and Dissertations

A set of laboratory experiments was carried out to distinguish flow characteristics(bed origin, shear velocity, turbulence intensity, turbulent kinetic energy) between beds of differing gravel angularity. Ten vertical profiles of velocity measurements were taken from angular and rounded fixed gravel beds with a 16 MHz micro acoustic Doppler velocimeter (ADV) sampling at 50 Hz. Both gravel beds had a bottom slope of 0.2% and were in the intermediate - roughness scale. Shear velocities were calculated using three common methods: St Venant, Reynolds stress, and Clauser. The Reynolds stress method resulted in the closest visual match to turbulence distributions proposed by …

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A Gis-Based Strategy For Managing Levee Simulation Data, Jeffrey R. Handy Jul 2008

A Gis-Based Strategy For Managing Levee Simulation Data, Jeffrey R. Handy

Theses and Dissertations

Understanding and improving the state of the nation's levees has become a national priority following the devastating events surrounding Hurricanes Katrina and Rita. Federal legislation passed in 2007 created a new national Committee on Levee Safety and spurred the development of the National Levee Database, a central repository of information relating to the location and state of levees across the United States (Water Resources Development Act, 2007). One of the major goals in developing such a database is to improve the safety of America's levees. The National Levee Database, however, does not include features for storing seepage and slope stability …

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Evaluating Shallow-Flow Rock Structures As Scour Countermeasures At Bridges, Benjamin P. Dahle Jul 2008

Evaluating Shallow-Flow Rock Structures As Scour Countermeasures At Bridges, Benjamin P. Dahle

Theses and Dissertations

The Utah Department of Transportation commissioned a study to determine whether or not shallow-flow rock structures could reliably be used at bridge abutments in place of riprap. Research was conducted in a two-phase effort beginning with numerical modeling and ending with field verification of model findings. As part of phase one, two finite element meshes were created in Surface-water Modeling Software (SMS) and analyzed with FESWMS-2DH. Second, field studies were conducted and a preliminary database was developed to track field studies conducted on 98 shallow-flow rock structures in Utah. Data organization in ArcGIS® and Microsoft Access® is presented followed by …

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