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2014

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Articles 721 - 735 of 735

Full-Text Articles in Civil Engineering

Responses Of Underground Structures Subjected To Blast Loading, Soufiane Nezilli Jan 2014

Responses Of Underground Structures Subjected To Blast Loading, Soufiane Nezilli

Dissertations and Theses

Terrorism against American citizens and assets is real and growing. The number and intensity of domestic and international terrorist events, along with the September 11, 2001, attacks, change the way Americans think and live. According to the Blue Ribbon Panel (BRP) on Bridge and Tunnel Security assigned by AASHTO, the US transportation system consists of 337 highway tunnels and 211 transit tunnels in 2003. The number is expected to grow in the near future. These tunnels are subjected to the threats of internal explosion, either accidental or maliciously intentional. Explosions inside transportation tunnels would result in direct casualties; and the …

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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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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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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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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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Longitudinal Analysis Of Crash Frequency Data, Mojtaba Ale Mohammadi Jan 2014

Longitudinal Analysis Of Crash Frequency Data, Mojtaba Ale Mohammadi

Doctoral Dissertations

"This study comprises mainly of three papers. First, a systematic evaluation of the effects of Missouri's Strategic Highway Safety Plan between 2004 and 2007 is presented. Negative binomial regression models were developed for the before-through-change conditions for the various collision types and crash severities. The models were used to predict the expected number of crashes assuming with and without the implementation of MSHSP. This procedure estimated significant reductions of 10% in crashes frequency and a 30% reduction for fatal crashes. Reductions in the number of different collision types were estimated to be 18-37%. The results suggest that the MSHSP was …

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A Unified Bond Theory, Probabilistic Meso-Scale Modeling, And Experimental Validation Of Deformed Steel Rebar In Normal Strength Concrete, Chenglin Wu Jan 2014

A Unified Bond Theory, Probabilistic Meso-Scale Modeling, And Experimental Validation Of Deformed Steel Rebar In Normal Strength Concrete, Chenglin Wu

Doctoral Dissertations

"Bond between deformed rebar and concrete is affected by rebar deformation pattern, concrete properties, concrete confinement, and rebar-concrete interfacial properties. Two distinct groups of bond models were traditionally developed based on the dominant effects of concrete splitting and near-interface shear-off failures. Their accuracy highly depended upon the test data sets selected in analysis and calibration. In this study, a unified bond model is proposed and developed based on an analogy to the indentation problem around the rib front of deformed rebar. This mechanics-based model can take into account the combined effect of concrete splitting and interface shear-off failures, resulting in …

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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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Evaluation Of The Empirical Deck Design For Vehicular Bridges, Georges El-Gharib Jan 2014

Evaluation Of The Empirical Deck Design For Vehicular Bridges, Georges El-Gharib

UNF Graduate Theses and Dissertations

This research evaluated the feasibility of the empirical design method for reinforced concrete bridge decks for the Florida Department of Transportation [FDOT]. There are currently three methods used for deck design: empirical method, traditional method and finite element method. This research investigated and compared the steel reinforcement ratios and the stress developed in the reinforcing steel for the three different methods of deck design. This study included analysis of 15 bridge models that met the FDOT standards. The main beams were designed and load rated using commercial software to obtain live load deflections. The bridges were checked to verify that …

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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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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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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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