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2014

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Articles 1471 - 1500 of 1522

Full-Text Articles in Civil and Environmental Engineering

A Multi-Modal Continuous-Systems Model Of A Novel High-Q Disk Resonator In A Viscous Liquid, Mohamad S. Sotoudegan, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Oliver Brand Jan 2014

A Multi-Modal Continuous-Systems Model Of A Novel High-Q Disk Resonator In A Viscous Liquid, Mohamad S. Sotoudegan, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

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Response Of Free-Living Nitrogen-Fixing Microorganisms To Land Use Change In The Amazon Rainforest, Babur S. Mirza, C. Potisap, K. Nusslein, B. Bohannan, J. L.M. Rodrigues Jan 2014

Response Of Free-Living Nitrogen-Fixing Microorganisms To Land Use Change In The Amazon Rainforest, Babur S. Mirza, C. Potisap, K. Nusslein, B. Bohannan, J. L.M. Rodrigues

Civil and Environmental Engineering Faculty Publications

The Amazon rainforest, the largest equatorial forest in the world, is being cleared for pasture and agricultural use at alarming rates. Tropical deforestation is known to cause alterations in microbial communities at taxonomic and phylogenetic levels, but it is unclear whether microbial functional groups are altered. We asked whether free-living nitrogen-fixing microorganisms (diazotrophs) respond to deforestation in the Amazon rainforest, using analysis of the marker gene nifH. Clone libraries were generated from soil samples collected from a primary forest, a 5-year-old pasture originally converted from primary forest, and a secondary forest established after pasture abandonment. Although diazotroph richness did not …

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The Impact Of Slit And Detention Dams On Debris Flow Control Using Gstars 3.0, Leila Hassan-Esfahani, Mohammad Ebrahim Banihabib Jan 2014

The Impact Of Slit And Detention Dams On Debris Flow Control Using Gstars 3.0, Leila Hassan-Esfahani, Mohammad Ebrahim Banihabib

Civil and Environmental Engineering Faculty Publications

Sedimentation, Modeling, GSTARS3.0, Debris flow, Slit dam, Detention dam

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Stability Analysis Of The Slope Along Us-2 Between Epoufette Bay And The Cut River Bridge, Stephanie Watts-Garcia Jan 2014

Stability Analysis Of The Slope Along Us-2 Between Epoufette Bay And The Cut River Bridge, Stephanie Watts-Garcia

Dissertations, Master's Theses and Master's Reports - Open

Recently, water was observed flowing from a section of steep slope along US-2 near St. Ignace, Michigan in addition to soil sloughing in the area where the water is flowing from the slope. An inspection of the area also showed the presence of sinkholes. The original construction drawing for US-2 also indicated that sinkholes were present in this area prior to road construction in 1948. An investigation was conducted to determine the overall stability of the slope. The slope consists primarily of aeolian sand deposits. Laboratory testing determined the shear strength of the slope material to have a friction angle …

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Characterizing And Improving Production Of Fermentable Sugars And Co-Products From A Forest Product Industry Wastewater Stream, Jifei Liu Jan 2014

Characterizing And Improving Production Of Fermentable Sugars And Co-Products From A Forest Product Industry Wastewater Stream, Jifei Liu

Dissertations, Master's Theses and Master's Reports - Open

Hardboard processing wastewater was evaluated as a feedstock in a bio refinery co-located with the hardboard facility for the production of fuel grade ethanol. A thorough characterization was conducted on the wastewater and the composition changes of which during the process in the bio refinery were tracked. It was determined that the wastewater had a low solid content (1.4%), and hemicellulose was the main component in the solid, accounting for up to 70%. Acid pretreatment alone can hydrolyze the majority of the hemicellulose as well as oligomers, and over 50% of the monomer sugars generated were xylose. The percentage of …

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Model Updating And Structural Health Monitoring Of Horizontal Axis Wind Turbines Via Advanced Spinning Finite Elements And Stochastic Subspace Identification Methods, Antonio Velazquez Hernandez Jan 2014

Model Updating And Structural Health Monitoring Of Horizontal Axis Wind Turbines Via Advanced Spinning Finite Elements And Stochastic Subspace Identification Methods, Antonio Velazquez Hernandez

Dissertations, Master's Theses and Master's Reports - Open

Wind energy has been one of the most growing sectors of the nation’s renewable energy portfolio for the past decade, and the same tendency is being projected for the upcoming years given the aggressive governmental policies for the reduction of fossil fuel dependency. Great technological expectation and outstanding commercial penetration has shown the so called Horizontal Axis Wind Turbines (HAWT) technologies. Given its great acceptance, size evolution of wind turbines over time has increased exponentially. However, safety and economical concerns have emerged as a result of the newly design tendencies for massive scale wind turbine structures presenting high slenderness ratios …

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Modeling Dynamics Of Ozone And Nitrogen Oxides At Summit, Greenland With A 1-D Process-Scale Model, Keenan Anton Murray Jan 2014

Modeling Dynamics Of Ozone And Nitrogen Oxides At Summit, Greenland With A 1-D Process-Scale Model, Keenan Anton Murray

Dissertations, Master's Theses and Master's Reports - Open

This work presents a 1-D process scale model used to investigate the chemical dynamics and temporal variability of nitrogen oxides (NOx) and ozone (O3) within and above snowpack at Summit, Greenland for March-May 2009 and estimates surface exchange of NOx between the snowpack and surface layer in April-May 2009. The model assumes the surface of snowflakes have a Liquid Like Layer (LLL) where aqueous chemistry occurs and interacts with the interstitial air of the snowpack. Model parameters and initialization are physically and chemically representative of snowpack at Summit, Greenland and model results are compared to …

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Spatio-Temporal Prediction Of Root Zone Soil Moisture Using Multivariate Relevance Vector Machines, B. Zaman, Mac Mckee Jan 2014

Spatio-Temporal Prediction Of Root Zone Soil Moisture Using Multivariate Relevance Vector Machines, B. Zaman, Mac Mckee

Civil and Environmental Engineering Faculty Publications

oot zone soil moisture at one and two meter depths are forecasted four days into the future. In this article, we propose a new multivariate output prediction approach to root zone soil moisture assessment using learning machine models. These models are known for their robustness, efficiency, and sparseness; they provide a statistically sound approach to solving the inverse problem and thus to building statistical models. The multivariate relevance vector machine (MVRVM) is used to build a model that forecasts soil moisture states based upon current soil moisture and soil temperature conditions. The methodology combines the data at different depths from …

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Timoshenko Beam Model For Lateral Vibration Of Liquid-Phase Microcantilever-Based Sensors, Joshua A. Schultz, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Nicholas J. Nigro, Luke A. Beardslee, Oliver Brand Jan 2014

Timoshenko Beam Model For Lateral Vibration Of Liquid-Phase Microcantilever-Based Sensors, Joshua A. Schultz, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Nicholas J. Nigro, Luke A. Beardslee, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

Dynamic-mode microcantilever-based devices are potentially well suited to biological and chemical sensing applications. However, when these applications involve liquid-phase detection, fluid-induced dissipative forces can significantly impair device performance. Recent experimental and analytical research has shown that higher in-fluid quality factors (Q) are achieved by exciting microcantilevers in the lateral flexural mode. However, experimental results show that, for microcantilevers having larger width-to-length ratios, the behaviors predicted by current analytical models differ from measurements. To more accurately model microcantilever resonant behavior in viscous fluids and to improve understanding of lateral-mode sensor performance, a new analytical model is developed, incorporating both …

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Restraint Moments Due To Thermal Gradients In Continuous Prestressed Concrete Girder Bridges, Sushovan Ghimire Jan 2014

Restraint Moments Due To Thermal Gradients In Continuous Prestressed Concrete Girder Bridges, Sushovan Ghimire

LSU Master's Theses

This research is motivated by the need to develop new bridges, using new materials and construction details to achieve the goal of building longer span bridges that are safe and durable. The study of precast/prestressed concrete bridges made continuous started early in the 1960’s. Continuous bridges have many advantages compared to simple span bridges such as reduction in structural depth, riding comfort and reserve load capacity under overload conditions. They also eliminate joints that require a lot of maintenance and cause deterioration in some cases. The design and construction of continuous bridges requires the consideration of many factors that are …

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Determining The Location Of Congestion Hot Spots In Urban Areas Using Image Analysis, Aditya Mokkapati Jan 2014

Determining The Location Of Congestion Hot Spots In Urban Areas Using Image Analysis, Aditya Mokkapati

LSU Master's Theses

The identification of congestion hot spots plays an important role in congestion monitoring of highway and arterial systems. Traditionally, vehicle detection systems or probe vehicles are used to measure travel time and identify congestion hot spots. This approach is time-consuming and resource intensive. With the advent of new technologies like crowdsourcing, travel time can be collected more cost-effectively using fewer resources. The research presented in this paper develops a new methodology to identify congestion hot spots in an urban area using freely available historical speed data gathered by Google and published as a traffic layer in Google maps. The methodology …

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The 6th Mode Of Transportation, Robert O. Walton Jan 2014

The 6th Mode Of Transportation, Robert O. Walton

Publications

The five modes of freight transportation are normally characterized as motor carriers, railroads, airlines, water carriers, and pipelines. This paper will attempt to position the Internet as the sixth mode of transportation. This paper compares the strengths and weaknesses of the traditional five modes of transportation against the proposed 6th mode of the Internet. Without including the Internet as a mode of transportation, and tracking the economic value that it adds to the economy, the economic impact of the Internet as a mode is not considered. The recommendation of this study is that the Internet should be added to the …

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Implementing Green Roofs On Movie Theaters And Shopping Centers: Business Cases In Profitable Sustainability, Ryan J. Miller Jan 2014

Implementing Green Roofs On Movie Theaters And Shopping Centers: Business Cases In Profitable Sustainability, Ryan J. Miller

Pomona Senior Theses

This thesis presents the business case for installing green roofs on movie theaters and shopping centers. These businesses can then derive increased profits from the environmental benefits of reduced energy use and increased stormwater retention. After presenting the basic design and benefits of a green roof, the thesis develops stand-alone business plans for a movie theater and shopping center. The author finds that green roofs are a profitable sustainability solution for the commercial enterprise.

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Development Of Traffic Safety Zones And Integrating Macroscopic And Microscopic Safety Data Analytics For Novel Hot Zone Identification, Jaeyoung Lee Jan 2014

Development Of Traffic Safety Zones And Integrating Macroscopic And Microscopic Safety Data Analytics For Novel Hot Zone Identification, Jaeyoung Lee

Electronic Theses and Dissertations

Traffic safety has been considered one of the most important issues in the transportation field. With consistent efforts of transportation engineers, Federal, State and local government officials, both fatalities and fatality rates from road traffic crashes in the United States have steadily declined from 2006 to 2011.Nevertheless, fatalities from traffic crashes slightly increased in 2012 (NHTSA, 2013). We lost 33,561 lives from road traffic crashes in the year 2012, and the road traffic crashes are still one of the leading causes of deaths, according to the Centers for Disease Control and Prevention (CDC). In recent years, efforts to incorporate traffic …

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Climate And Landscape Controls On Seasonal Water Balance At The Watershed Scale, Xi Chen Jan 2014

Climate And Landscape Controls On Seasonal Water Balance At The Watershed Scale, Xi Chen

Electronic Theses and Dissertations

The main goal of this dissertation is to develop a seasonal water balance model for evaporation, runoff and water storage change based on observations from a large number of watersheds, and further to obtain a comprehensive understanding on the dominant physical controls on intra-annual water balance. Meanwhile, the method for estimating evaporation and water storage based on recession analysis is improved by quantifying the seasonal pattern of the partial contributing area and contributing storage to base flow during low flow seasons. A new method for quantifying seasonality is developed in this research. The difference between precipitation and soil water storage …

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Graphical Performance Measures For Practitioners To Triage Split Failure Trouble Calls, Richard S. Freije, Alexander M. Hainen, Amanda L. Stevens, Howell Li, W Benjamin Smith, Hayley Summers, Christopher M. Day, James R. Sturdevant, Darcy M. Bullock Jan 2014

Graphical Performance Measures For Practitioners To Triage Split Failure Trouble Calls, Richard S. Freije, Alexander M. Hainen, Amanda L. Stevens, Howell Li, W Benjamin Smith, Hayley Summers, Christopher M. Day, James R. Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

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Evaluation Of Triploid Oysters As A Tool To Assess Short- And Long-Term Seafood Contamination Of Oil Spill-Impacted Areas, Martin Scott Miles Jan 2014

Evaluation Of Triploid Oysters As A Tool To Assess Short- And Long-Term Seafood Contamination Of Oil Spill-Impacted Areas, Martin Scott Miles

LSU Doctoral Dissertations

Many of the organic components of oil have the capacity to persist in the environment, bioaccumulate in tissues, and are toxic to surrounding organisms. Since the early 1970s, environmental assessment programs have utilized bivalves as monitoring tools of chemical contaminants in the marine environment. Because of their sedentary and filter-feeding habit (bioaccumulation), mussels and oysters been employed as sentinel organisms in environmental quality monitoring studies in coastal ecosystems. The use of indigenous (diploid) bivalves for biomonitoring water quality is limited during the summer months due to high stress and changes in biochemical composition induced by reproductive development. In this work …

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Improving Intersection Behavior Through Delay-Based Left Turn Phase Initiation, Steven M. Lavrenz, Alexander M. Hainen, Amanda L. Stevens, Christopher M. Day, Howell Li, Richard Freije, W Benjamin Smith, Hayley Summers, James R. Sturdevant, Darcy M. Bullock Jan 2014

Improving Intersection Behavior Through Delay-Based Left Turn Phase Initiation, Steven M. Lavrenz, Alexander M. Hainen, Amanda L. Stevens, Christopher M. Day, Howell Li, Richard Freije, W Benjamin Smith, Hayley Summers, James R. Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

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Assessing Longitudinal Arterial Performance And Traffic Signal Retiming Outcomes, Steven M. Lavrenz, Christopher M. Day, W Benjamin Smith, James R. Sturdevant, Darcy M. Bullock Jan 2014

Assessing Longitudinal Arterial Performance And Traffic Signal Retiming Outcomes, Steven M. Lavrenz, Christopher M. Day, W Benjamin Smith, James R. Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

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High-Resolution Event-Based Data At Diamond Interchanges: Performance Measures And Optimizing Ring Displacement, Alexander M. Hainen, Amanda L. Stevens, Richard S. Freije, Christopher M. Day, James R. Sturdevant, Darcy M. Bullock Jan 2014

High-Resolution Event-Based Data At Diamond Interchanges: Performance Measures And Optimizing Ring Displacement, Alexander M. Hainen, Amanda L. Stevens, Richard S. Freije, Christopher M. Day, James R. Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

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Performance Ranking Of Arterial Corridors Using Travel Time And Travel Time Reliability Metrics, Christopher M. Day, Stephen Remias, Howell Li, Michelle M. Mekker, Margaret L. Mcnamara, Ed Cox, Darcy M. Bullock Jan 2014

Performance Ranking Of Arterial Corridors Using Travel Time And Travel Time Reliability Metrics, Christopher M. Day, Stephen Remias, Howell Li, Michelle M. Mekker, Margaret L. Mcnamara, Ed Cox, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

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Design Considerations For A Rotating Retractable Stadium Roof, Charles S. Jenkins Jan 2014

Design Considerations For A Rotating Retractable Stadium Roof, Charles S. Jenkins

Honors Theses

This thesis presents a novel type of retractable roof, adapting the pivot-based retraction system used in Miller Park to a stadium without a circular geometry. Existing stadiums with retractable roofs are reviewed, and lessons learned are used to present theoretical structural engineering design for a roof truss and recommendations for carriers. The presented concept likely requires light-weight structural systems and closely-spaced roof trusses to minimize loads on roof carriers. Actual mechanical designs of the roof carriers are quite complex as they must be able to roll in two directions and pivot about a third. The design herein is incomplete for …

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Analysis Of A 10-Year Nearshore Wave Database And Its Implications To Littoral Processes, Luis Humberto Montoya Jan 2014

Analysis Of A 10-Year Nearshore Wave Database And Its Implications To Littoral Processes, Luis Humberto Montoya

UNF Graduate Theses and Dissertations

The variability of the nearshore wave climate is investigated via the analysis of over 10 years of Acoustic Doppler Current Profiler (ADCP) data from a gauge deployed at Melbourne Beach, FL. Examples of large yearly variability in the significant wave height, peak period, mean direction and energy distribution are found in the data. Estimates of the averaged spectra for the entire record show that the average wave energy is distributed almost symmetrically with the peak being close to shore-normal. It was expected that the peak would be shifted towards the north of shore-normal considering net north to south longshore sediment …

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Shear Strength Parameters Of Sand Fly Ash Cement Mixtures, Oksana Nikolayevna Spears Jan 2014

Shear Strength Parameters Of Sand Fly Ash Cement Mixtures, Oksana Nikolayevna Spears

UNF Graduate Theses and Dissertations

According to a 2012 American Coal Ash Association Coal production Survey Report, US coal fired power plants produced more than 109 million tons of waste that year. Approximately half of this waste is the valuable by-product fly ash. There are three classes of fly ash: cementitious class C and non-cementitious classes F and N. Over half of the fly ash produced is used in the geotechnical/construction industries. Most geotechnical soil stabilization studies using fly ash are focused on controlling shrink-swell potential of clays. This study utilized the less desirable class F fly ash to assess the improvement of shear strength …

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Examining Optimal Form Of Two Scale Approximation (Tsa) For Calculating Snl Source Term, Dorukhan Ardag Jan 2014

Examining Optimal Form Of Two Scale Approximation (Tsa) For Calculating Snl Source Term, Dorukhan Ardag

UNF Graduate Theses and Dissertations

Nonlinear four-wave interactions (Snl) are critical for acquiring realistic spectra needed by operational wave models. High computational demand to calculate these interactions led to an approximation method named the Discrete Interaction Approximation (DIA) to be used broadly in the major operational wave models for a long time. However, the accuracy of the DIA has been controversial since it was first introduced and more precise approximations such as the Two Scale Approximation (TSA in short) are now available. The only issue with the initial TSA`s efficiency is performing an order of a magnitude slower than the DIA in speed. …

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Factors Affecting Storm Characteristics In The Battery And Vicinity, Shannon A. Kay Jan 2014

Factors Affecting Storm Characteristics In The Battery And Vicinity, Shannon A. Kay

UNF Graduate Theses and Dissertations

Tropical cyclones (TCs) Irene and Sandy caused major damages in back to back years to the most densely populated city in the United States stunning the residents with storms linked to seemingly impossible probabilities. Such activity has raised questions about the effect of non-stationary aspects within atmospheric circulation on storm behavior and some assumptions inherent in previous hazard studies of the New York City (NYC) area. This study analyzes statistical aspects of hazard quantification for this area related to this non-stationarity and statistical characterization. In particular this study investigates the presence of multiple populations of storms, it also tests current …

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The Effects Of Rain On Traffic Safety And Operations On Florida Freeways, Michelle L. Angel Jan 2014

The Effects Of Rain On Traffic Safety And Operations On Florida Freeways, Michelle L. Angel

UNF Graduate Theses and Dissertations

Although the association between weather and traffic variables or crash events appear intuitive to motorists, quantifying the effects that weather, especially rain, has on driver response in travel speeds, traffic demands, and susceptibility of accident occurrence is needed to evaluate practical aspects of traffic operations and safety measures. Previous studies have researched driver responses to inclement weather on roadways located primarily in northern and western regions of the United States (U.S.), Canada, and Europe. However, driver familiarity to local weather conditions is a factor that should be considered in determining inclement weather effects on traffic variables and crash occurrence. This …

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Rapid Repair Of Severely Damaged Rc Columns Under Combined Loading Of Flexure, Shear, And Torsion With Externally Bonded Cfrp, Ruili He Jan 2014

Rapid Repair Of Severely Damaged Rc Columns Under Combined Loading Of Flexure, Shear, And Torsion With Externally Bonded Cfrp, Ruili He

Doctoral Dissertations

"This research aimed to develop a technique to rapidly repair reinforced concrete (RC) bridge columns for emergency service restoration after severe earthquake damage has occurred. Experimental and analytical studies were conducted to study the performance and effectiveness of the proposed repair method. The experimental study included a series of 1/2-scale RC square bridge columns originally tested to failure under constant axial and increasing cyclic lateral loadings resulting in combined flexure, shear, and torsion with different torsional-to-flexural moment ratios. Using externally bonded carbon fiber reinforced polymer (CFRP) sheets, each column was repaired over a 3-day period and then retested under the …

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Plant Uptake Of Environmental Contaminants: Applications In Phytoscreening, Matthew Alan Limmer Jan 2014

Plant Uptake Of Environmental Contaminants: Applications In Phytoscreening, Matthew Alan Limmer

Doctoral Dissertations

"Plants interact directly with their surroundings, extracting nutrients and water from the subsurface to support growth and development of the plant. Through the roots, plants also exude and uptake numerous chemicals. Many of the pathways can also be used by environmental contaminants to be translocated to above ground plant tissues. Such uptake of contaminants has proven useful in remediation and phytoscreening - the use of plants to delineate contaminant plumes. Sampling of trees at contaminated field sites has been used to identify areas of groundwater contaminated with a variety of chlorinated solvents. The use of plants as contaminant biosensors requires …

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Seismic Repair Of Bridge Columns With Interlocking Spirals And Fractured Bars, Yang Yang Jan 2014

Seismic Repair Of Bridge Columns With Interlocking Spirals And Fractured Bars, Yang Yang

Doctoral Dissertations

"During earthquakes, reinforced concrete (RC) bridge columns may experience different levels of damage such as cracking, spalling, or crushing of concrete and yielding, buckling, or fracture of reinforcing bars. This study developed and assessed permanent and emergency methods to repair damaged bridge columns with fractured longitudinal reinforcement through experimental and modeling work. The permanent repair method involved replacement of the plastic hinge region by removal of spirals, replacement of longitudinal bar segments by mechanically splicing with new bars segments attached with mechanical couplers, replacement of concrete, and installation of an externally bonded carbon fiber reinforced polymer (CFRP) jacket. The emergency …

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