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Articles 901 - 930 of 1183

Full-Text Articles in Civil and Environmental Engineering

A Trophic State Analysis Of Lakes In Yellowstone National Park, Anthony Alexander Melcher Mar 2013

A Trophic State Analysis Of Lakes In Yellowstone National Park, Anthony Alexander Melcher

Theses and Dissertations

Eutrophication is of interest in the field of water quality. Eutrophic lakes, when used as sources for drinking water, can cause problems during the treatment process, for example algae blooms can clog filters, requiring more water and energy to be used during the cleaning and backwashing of the filters. Excess nutrient loading and eutrophication can also harm fish and aquatic life habitats. Certain species of algae and cyanobacteria can be toxic to humans as well. Since 1998, Dr. A. Woodruff Miller has collected water samples from 46 lakes and ponds in Yellowstone National Park. The Carlson Trophic State Index, the …

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Passive Force On Skewed Abutments With Mechanically Stabilized Earth (Mse) Wingwalls Based On Large-Scale Tests, Bryan William Franke Mar 2013

Passive Force On Skewed Abutments With Mechanically Stabilized Earth (Mse) Wingwalls Based On Large-Scale Tests, Bryan William Franke

Theses and Dissertations

Passive force-deflection behavior for densely compacted backfills must be considered in bridge design to ensure adequate resistance to both seismic and thermally induced forces. Current codes and practices do not distinguish between skewed and non-skewed bridge abutment geometries; however, in recent years, numerical models and small-scale, plane-strain laboratory tests have suggested a significant reduction in passive force for skewed bridge abutments. Also, various case studies have suggested higher soil stresses might be experienced on the acute side of the skew angle. For these reasons, three large-scale tests were performed with abutment skew angles of 0, 15 and 30 degrees using …

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Lateral Resistance Of Piles Near Vertical Mse Abutment Walls At Provo Center Street, Kent R. Nelson Mar 2013

Lateral Resistance Of Piles Near Vertical Mse Abutment Walls At Provo Center Street, Kent R. Nelson

Theses and Dissertations

Full scale lateral load tests were performed on four piles located at various distances behind MSE walls. Three of the four test piles were production piles used to support bridges, and the other pile a production pile used as part of the bridge abutment. The objective of the testing was to determine the effect of spacing from the wall on the lateral resistance of the piles and on the force resisted by the MSE reinforcement. Lateral load-displacement curves were developed for pile at various spacing and with various reinforcement ratio (reinforcement length, L divided by wall height, H). The force …

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Evaluation Of Passive Force On Skewed Bridge Abutments With Large-Scale Tests, Aaron Kirt Marsh Mar 2013

Evaluation Of Passive Force On Skewed Bridge Abutments With Large-Scale Tests, Aaron Kirt Marsh

Theses and Dissertations

Accounting for seismic forces and thermal expansion in bridge design requires an accurate passive force versus backwall deflection relationship. Current design codes make no allowances for skew effects on the development of the passive force. However, small-scale experimental results and available numerical models indicate that there is a significant reduction in peak passive force as skew angle increases for plane-strain cases. To further explore this issue large-scale field tests were conducted at skew angles of 0°, 15°, and 30° with unconfined backfill geometry. The abutment backwall was 11 feet (3.35-m) wide by 5.5 feet (1.68-m) high, and backfill material consisted …

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Starch Resin Moisture Level Effect On Injection Molding Processability And Molded Part Mechanical Properties With Pure Starch Resin And Polymer Blends, Jordan M. Ellingson Mar 2013

Starch Resin Moisture Level Effect On Injection Molding Processability And Molded Part Mechanical Properties With Pure Starch Resin And Polymer Blends, Jordan M. Ellingson

Theses and Dissertations

The current and forecasted global consumption of plastic packaging and products through the 21st century combined with the already reported and growing negative impact of plastics on the environment due to plastics being synthesized from nonrenewable resources that do not biodegrade is of serious concern. However, recent advances in starch technology including the development of thermoplastic starch (TPS) materials —polymers that are both renewable and biodegradable—have brought hope to reducing this impact. The mechanical properties of thermoplastic starch have often been improved by blending with synthetic polymers. One issue that arises with blending is volatilization of the melt from moisture …

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Location-Allocation Optimization Of Supply Chain Distribution Networks: A Case Study, Mark Nicholas Helberg Mar 2013

Location-Allocation Optimization Of Supply Chain Distribution Networks: A Case Study, Mark Nicholas Helberg

Theses and Dissertations

The location of distribution centers is an important strategic decision in supply chain design, particularly as it relates to service quality, productivity, and profitability of the firm. There has been extensive research performed on distribution location models which require the use of complex algorithms and assumptions that make use of these models difficult in practice for small and medium enterprises (SMEs) that have limited capital and resources. Studies have also failed to capture and quantify potential business results of using more sophisticated methods. In this study, a deterministic and static location-allocation model is designed using a prototype software tool. The …

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Structural Design Of Flexible Etfe Atrium Enclosures Using A Cable-Spring Support System, Ryan Paul Bessey Dec 2012

Structural Design Of Flexible Etfe Atrium Enclosures Using A Cable-Spring Support System, Ryan Paul Bessey

Theses and Dissertations

This research designed and analyzed an innovative structural support system for ETFE (ethylene tetrafluoroethylene) atrium roofs between buildings. A cable-spring system was conceived, which is much lighter and more flexible than arches, frames, trusses, and beams which usually support ETFE roofs. Flexibility was a desirable property because the displacements may vary significantly among the buildings supporting the ETFE atrium roof during wind and seismic loading. The springs in the cable-spring system allow large differential displacements without exerting large support reactions on the buildings. The flexibility of the cable-spring system was compared to the cable-strut system which is used to support …

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Complexity Of Bed-Load Transport In Gravel Bed Streams: Data Collection, Prediction, And Analysis, Darren D. Hinton Dec 2012

Complexity Of Bed-Load Transport In Gravel Bed Streams: Data Collection, Prediction, And Analysis, Darren D. Hinton

Theses and Dissertations

Bedload transport has long been known for its complexity. Despite decades of research, significant gaps of understanding exist in the ability to assess and predict bedload movement. This work introduces a comprehensive bedload database that is a compilation of field samples collected over the past 40 years; compares prediction formulae using a subset of the database; evaluates the influence of the armor layer on stream response to sediment input based on a hypothesis linked to one of the tested formulae, presents a mathematically manipulation of the empirical Pagosa Good/Fair formula for bedload transport into a format similar to the semi-empirical …

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Best Practices Using Building Information Modeling In Commercial Construction, Simon Beveridge Dec 2012

Best Practices Using Building Information Modeling In Commercial Construction, Simon Beveridge

Theses and Dissertations

There has been an increase in adoption of building information modeling (BIM) by commercial contractors over the past few years but there is not a clear indication of current application or the frequency of each use. This research was undertaken to determine the frequency and best practices of using BIM in commercial construction. Leading commercial contracting firms were contacted and employees were selected to complete a telephone survey that was designed to determine how they are using BIM. It was found that BIM is being used with more frequency on projects, with plans to continue to implement it even further …

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Two-Refinement By Pillowing For Structured Hexahedral Meshes, J. Bruce Malone Dec 2012

Two-Refinement By Pillowing For Structured Hexahedral Meshes, J. Bruce Malone

Theses and Dissertations

A number of methods for adaptation of existing all-hexahedral grids by localized refinement have been developed; however, none ideally fit all refinement needs. This thesis presents the structure to a method of two-refinement developed for conformal, structured, all-hexahedral grids that offers flexibility beyond what has been offered to date. The method is fundamentally based on pillowing pairs of sheets of hexes. This thesis also suggests an implementation of the method, shows the results of examples refined using it and compares these results to results from implementing three-refinement on the same examples.

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Seismic Response Of Stiffening Elastic Systems, Andrew Scott Morgan Dec 2012

Seismic Response Of Stiffening Elastic Systems, Andrew Scott Morgan

Theses and Dissertations

Traditional seismic load resisting systems in buildings are designed to undergo inelastic deformations in order to dissipate energy, resulting in residual displacements. This work explores an approach to eliminate these residual displacements. The systems investigated have low initial stiffness which increases at a predefined displacement, and are therefore called stiffening elastic systems. This thesis begins with an examination of single-degree-of-freedom stiffening elastic systems. A case study is presented which suggests that the benefits from stiffening elastic behavior may be limited to systems which would have long periods if designed traditionally. A thorough parameter study is also presented which indicates the …

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Lateral Resistance Of Piles Near Vertical Mse Abutment Walls, Jacob S. Price Aug 2012

Lateral Resistance Of Piles Near Vertical Mse Abutment Walls, Jacob S. Price

Theses and Dissertations

Full scale lateral load tests were performed on five piles located at various distances behind MSE walls. Three of the five test piles were production piles used to support bridges, and the other two piles were located behind a MSE wing walls adjacent to the bridge abutment. The objective of the testing was to determine the effect of spacing from the wall on the lateral resistance of the piles and on the force resisted by the MSE reinforcement. Tentative curves have been developed showing p-multiplier vs. normalized spacing behind wall for a length to height ratio of 1.1 and 1.6. …

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Buckling And Crippling Of Square Steel Thin-Walled Tubes Fabricated With Symmetrically-Overlapping U-Channels And Foam, David Camenish Gelder Jul 2012

Buckling And Crippling Of Square Steel Thin-Walled Tubes Fabricated With Symmetrically-Overlapping U-Channels And Foam, David Camenish Gelder

Theses and Dissertations

Testing and analysis has been performed on square steel thin-walled tubes fabricated using symmetrically-overlapping U-channels and foam. This research analyzes flange-to-flange attachment, effect of foam in the columns, effect of adhesive stiffness, and influence of steel thickness, as related to the local buckling loads, global buckling loads, and crippling loads. Four 14-foot (4.27 m) foam-filled, thin-walled, galvanized steel columns were manufactured by Novatek, Inc. and tested in axial compression with pinned boundary conditions. For three of the four configurations, the two-piece 4-in. (10.2-cm) square shell surrounded prefabricated polystyrene foam inserts; the fourth column had no foam insert. The column outer …

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A Comparative Study Of Strength And Stiffness Of Thin-Walled Specimens Fabricated By Fdm And 3d Printing Technologies, Miranda Rodrigo Jul 2012

A Comparative Study Of Strength And Stiffness Of Thin-Walled Specimens Fabricated By Fdm And 3d Printing Technologies, Miranda Rodrigo

Theses and Dissertations

Rapid Prototyped part failure constitutes a major issue for both RP providers and customers. When parts fail the reputation of the vendor is heavily deteriorated, customer dissatisfaction increase and replacement of the broken parts is often necessary to avoid the loss of future business. Product design teams often run into situations where Rapid Prototyped parts are not able to withstand shipping and handling and delivered broken or while demonstrating and examining the parts. When done in the face of customers this builds a perception of poor quality and lack of aptitude on the design group as well as the RP …

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A Server-Based Tool For Automating Modflow Simulations For Well Permitting Decision Support, David J. Jones Jul 2012

A Server-Based Tool For Automating Modflow Simulations For Well Permitting Decision Support, David J. Jones

Theses and Dissertations

Numeric groundwater modeling techniques can assist water resources regulators pursuing prudent and foresightful aquifer management decisions. Unfortunately, the amount of time and professional expertise required to wield modern groundwater models often exceeds the resources of regulating agencies – even for simple modeling tasks that are repetitive in nature. In an effort to increase the accessibility of groundwater modeling resources, a server-based automated well permitting decision support system was designed. The prototype system allows a user to 1) input properties for any number of candidate wells, 2) execute an associated MOFLOW model, and 3) view relevant results of the simulation on …

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Culvert Roughness Elements For Native Utah Fish Passage: Phase Ii, Suzanne Kim Monk Jul 2012

Culvert Roughness Elements For Native Utah Fish Passage: Phase Ii, Suzanne Kim Monk

Theses and Dissertations

Native fishes have become an increasingly important concern when designing fish passable culverts. Many operational culverts constrict waterways which increase velocities and prevent upstream passage of small fish species. The current method to ensure fish passage is to match the average cross sectional velocity to the sustained swim speed of the fish. This study investigates the passage rates of leatherside chub (Lepidomeda aliciae) and speckled dace (Rhinichthys osculus) at three sites (an arch culvert with substrate bottom, box culvert with bare bottom, and a stream section with no culvert) located on Salina Creek near Salina, UT. It was found that …

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Principal Components Analysis, Factor Analysis And Trend Correlations Of Twenty-Eight Years Of Water Quality Data Of Deer Creek Reservoir, Utah, Nicolas Alejandro Gonzalez Jul 2012

Principal Components Analysis, Factor Analysis And Trend Correlations Of Twenty-Eight Years Of Water Quality Data Of Deer Creek Reservoir, Utah, Nicolas Alejandro Gonzalez

Theses and Dissertations

I evaluated twenty-eight years (1980-2007) of spatial-temporal water quality data from Deer Creek Reservoir in Utah. The data came from three sampling points representing the lotic, transitional and lentic zones. The data included measurements of climatological, hydrological and water quality conditions at four depths; Surface, Above Thermocline, Below Thermocline and Bottom. The time frame spanned dates before and after the completion of the Jordanelle Reservoir (1987-1992), approximately fourteen miles upstream of Deer Creek. I compared temporal groupings and found that a traditional month distribution following standard seasons was not effective in characterizing the measured conditions; I developed a more representative …

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Structural Properties Of Iclt Wall Panels Composed Of Beetle Killed Wood, David Edward Wilson Jun 2012

Structural Properties Of Iclt Wall Panels Composed Of Beetle Killed Wood, David Edward Wilson

Theses and Dissertations

Interlocking Cross Laminated Timber (ICLT) wall panels are a new wood construction product similar to Cross Laminated Timber panels. Besides being an innovative structural system, they also utilize beetle killed timber from many of the forests that have been devastated by the Mountain Pine Beetle. Three tests were performed on three ply ICLT panels measuring 8 feet (2.44m) wide, 8 feet (2.44m) tall and 8.5 inches (21.6cm) thick to determine the racking, flexural and axial strengths of the wall panels. After each test was performed the walls were disassembled and investigated for cause of failure. Using the data from the …

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Reducing Residual Drift In Buckling-Restrained Braced Frames By Using Gravity Columns As Part Of A Dual System, Megan Boston Apr 2012

Reducing Residual Drift In Buckling-Restrained Braced Frames By Using Gravity Columns As Part Of A Dual System, Megan Boston

Theses and Dissertations

Severe earthquakes cause damage to buildings. One measure of damage is the residual drift. Large residual drifts suggest expensive repairs and could lead to complete loss of the building. As such, research has been conducted on how to reduce the residual drift. Recent research has focused on self-centering frames and dual systems, both of which increase the post-yield stiffness of the building during and after an earthquake. Self-centering systems have yet to be adopted into standard practice but dual systems are used regularly. Dual systems in steel buildings typically combine two types of traditional lateral force resisting systems such as …

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Sensitivity Of Resistivity Measurements On Concrete Bridge Decks To Operator-Controlled And Concrete Material Variables, Natasha Christine Barrus Apr 2012

Sensitivity Of Resistivity Measurements On Concrete Bridge Decks To Operator-Controlled And Concrete Material Variables, Natasha Christine Barrus

Theses and Dissertations

The objectives of this research were to investigate the sensitivity of two-prong and fourprong resistivity measurements to certain operator-controlled variables and to conduct a direct comparison of the sensitivity of two-prong and four-prong resistivity measurements to certain concrete material variables. Four full-factorial experiments were designed for this research. In the experimentation on operator-controlled variables with two-prong resistivity testing, main effects that are both statistically significant and practically important include hole depth and surface water. In the experimentation on operator-controlled variables with four-prong resistivity testing, probe position, surface water, and prong spacing are all neither statistically significant nor practically important. This …

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Passive Resistance Of Abutments With Mse Wingwalls, Nathanael G. Bingham Apr 2012

Passive Resistance Of Abutments With Mse Wingwalls, Nathanael G. Bingham

Theses and Dissertations

Large scale static lateral load tests were performed on a pile cap under varying sand backfill configurations: no backfill, full-width dense sand backfill, dense sand slip plane confined backfill, and two configurations of dense sand MSE wall confined backfills. Efforts were made to maintain the relative compaction of the backfills for each of the tests near the same value. The MSE wall panel arrangement was varied to determine the effect of different reinforcement configurations on the passive resistance and wall panel displacement. Passive force-displacement curves were generated from each test. It was found that the MSE design manual provided reasonable …

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Skew Effects On Passive Earth Pressures Based On Large-Scale Tests, Shon Joseph Jessee Apr 2012

Skew Effects On Passive Earth Pressures Based On Large-Scale Tests, Shon Joseph Jessee

Theses and Dissertations

The passive force-deflection relationship for abutment walls is important for bridges subjected to thermal expansion and seismic forces, but no test results have been available for skewed abutments. To determine the influence of skew angle on the development of passive force, lab tests were performed on a wall with skew angles of 0º, 15º, 30º, and 45º. The wall was 1.26 m wide and 0.61 m high and the backfill consisted of dense compacted sand. As the skew angle increased, the passive force decreased substantially with a reduction of 50% at a skew of 30º. An adjustment factor was developed …

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Damage Tolerance Of Unidirectional Carbon And Fiberglass Composites With Aramid Sleeves, Charles Andrew Sika Mar 2012

Damage Tolerance Of Unidirectional Carbon And Fiberglass Composites With Aramid Sleeves, Charles Andrew Sika

Theses and Dissertations

Unidirectional carbon fiber and fiberglass epoxy composite elements consolidated with aramid sleeves were radially impacted at 5 J (3.7 ft-lbs) and 10 J (7.4 ft-lbs), tested under compression, and compared to undamaged control specimens. These structural elements represent local members of open three-dimensional composite lattice structures (e.g., based on isogrid or IsoTruss® technologies). Advanced three-dimensional braiding techniques were used to continuously fabricate these specimens. The unidirectional core specimens, 8 mm (5/16 in) in diameter, were manufactured with various sleeve patterns. Bi-directional braided sleeves and unidirectional spiral sleeves ranged from a nominal full to half coverage. These specimens were tested for …

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Evaluating Climate Change Effects In Two Contrasting Reservoirs Using Two-Dimensional Water Quality And Hydrodynamic Models, Oliver Obregon Mar 2012

Evaluating Climate Change Effects In Two Contrasting Reservoirs Using Two-Dimensional Water Quality And Hydrodynamic Models, Oliver Obregon

Theses and Dissertations

I analyzed and compared impacts from global climate change (GCC) and land use change to Deer Creek (United States) a temperate reservoir and Aguamilpa (Mexico), a tropical reservoir by using calibrated CE-QUAL-W2 (W2) water quality and hydrodynamic models based on field data over an extended time period. I evaluated and compared the sensitivity to predicted GCC and land use changes. I individually evaluated changes to air temperature (TAIR), inflow rates (Q), and nutrient loads (PO4-P and NO3-NO2-N) followed by analysis of worst case scenarios. I developed analysis methods using indexes to represent the total …

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Study Of Water Quality Of Utah Lake Tributaries And The Jordan River Outlet For The Calibration Of The Utah Lake Water Salinity Model (Lksim), Gordon Killarney Liljenquist Mar 2012

Study Of Water Quality Of Utah Lake Tributaries And The Jordan River Outlet For The Calibration Of The Utah Lake Water Salinity Model (Lksim), Gordon Killarney Liljenquist

Theses and Dissertations

The water quality of Utah Lake is of great importance to agriculture, recreation, and wildlife. The Utah Lake Simulation Model (LKSIM) was created to accurately predict changes in water quality parameters. However, a potential limitation of LKSIM is the age of the underlying data which was gathered from 1930 to 1980. New sample data were collected from March 2009 through May 2011. Samples were taken from 13 tributaries, the Jordan River Outlet, and various wastewater treatment plants (WWTP). Upon dividing the collected data points into seasons and plotting them in Microsoft Excel, trendline equations were produced. These equations correlated TDS …

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Safety Issues Among Hispanic Construction Workers Along The Wasatch Front In Utah, Phavel Israel Loayza Chahuayo Dec 2011

Safety Issues Among Hispanic Construction Workers Along The Wasatch Front In Utah, Phavel Israel Loayza Chahuayo

Theses and Dissertations

During the last few decades immigration by foreigners seeking work in the construction industry in the United States has increased dramatically. Of those seeking jobs in construction, Hispanics represent the largest and fastest growing population. The proportion of reportable accidents among Hispanic on-site construction workers in the United States is higher than that of non-Hispanics. This trend of on-site construction accidents is evident not only in states that have traditionally high populations of Hispanics, such as New York, Florida, California, Arizona, and Texas, it is also manifested in the State of Utah. This research focused on causes of accidents among …

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A Performance-Based Model For The Computation Of Kinematic Pile Response Due To Lateral Spreading And Its Application On Select Bridges Damaged During The M7.6 Earthquake In The Limon Province, Costa Rica, Kevin W. Franke Dec 2011

A Performance-Based Model For The Computation Of Kinematic Pile Response Due To Lateral Spreading And Its Application On Select Bridges Damaged During The M7.6 Earthquake In The Limon Province, Costa Rica, Kevin W. Franke

Theses and Dissertations

Lateral spread is a seismic hazard associated with soil liquefaction in which permanent deformations are developed within the soil profile due to cyclic mobility. Lateral spread has historically been one of the largest causes of earthquake-related damage to infrastructure. One of the infrastructure components most at risk from lateral spread is that of deep foundations. Because performance-based engineering is increasingly becoming adopted in earthquake engineering practice, it would be beneficial for engineers and researchers to have a performance-based methodology for computing pile performance during a lateral spread event. This study utilizes the probabilistic performance-based framework developed by the Pacific Earthquake …

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Damage Tolerance Of Unidirectional Basalt/Epoxy Composites In Co-Cured Aramid Sleeves, Devin Nelson Allen Dec 2011

Damage Tolerance Of Unidirectional Basalt/Epoxy Composites In Co-Cured Aramid Sleeves, Devin Nelson Allen

Theses and Dissertations

Unidirectional basalt fiber rods consolidated with an aramid sleeve were measured for compression strength after impact at various energy levels and compared to undamaged control specimens. These structural elements represent local members of open three-dimensional composite lattice structures (e.g., based on isogrid or IsoTruss® technologies) that are continuously fabricated using advanced three-dimensional braiding techniques. The unidirectional core specimens, nominally 8 mm (5/16") and 11 mm (7/16") in diameter, were manufactured using bi-directional braided sleeves or unidirectional spiral sleeves with full or partial (approximately half) coverage of the core fibers. The 51 mm (2") specimens were shorter than the critical buckling …

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Damage Tolerance Of Buckling-Critical Unidirectional Carbon, Glass,And Basalt Fiber Composites In Co-Cured Aramid Sleeves, Michael D. Embley Dec 2011

Damage Tolerance Of Buckling-Critical Unidirectional Carbon, Glass,And Basalt Fiber Composites In Co-Cured Aramid Sleeves, Michael D. Embley

Theses and Dissertations

Compression strength after impact tests were conducted on unidirectional composite rods with sleeves. These elements represent local members of open three-dimensional composite lattice structures (e.g., based on isogrid or IsoTruss® technologies). The unidirectional cores composed of carbon, glass, or basalt fiber/epoxy composites were co-cured in aramid sleeves. Sleeve patterns included both bi-directional (unsymmetric) braids and unidirectional spiral wraps with sleeve coverage ranging from nominally half to full. The diameters were nominally 8 and 11 mm (5/16 and 7/16 in). The larger diameter had nominally twice the cross-sectional area, to quantify the effects of scaling. The specimens were long enough to …

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Reduction In Wick Drain Effectiveness In Typical Utah Clays, Gabriel M. Smith Dec 2011

Reduction In Wick Drain Effectiveness In Typical Utah Clays, Gabriel M. Smith

Theses and Dissertations

Consolidation theory states that decreasing the spacing of prefabricated vertical drains will decrease the time required to achieve primary consolidation. Previous field tests have shown that there exists a "critical" drain spacing, which is the point at which further spacing decrease does not decrease the time of primary consolidation. This "critical" spacing is thought to be due to disturbance effects from installation of the drains. Previous studies have found that the "critical" drain spacing may be dependent upon soil layering and drain and mandrel dimensions. Thin, interbedded clay layers have been found to be affected greatly due to the smear …

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