This thesis focuses on the development of a microscopic traffic simulation, emission and dispersion modeling system which aims at quantifying the effects of different types of traffic calming measures on vehicle emissions both at a link-level and at a network-level and on air quality at a corridor level using a scenario analysis. The study area is set in Montréal, Canada where a traffic simulation model for a dense urban neighborhood is extended with capabilities for microscopic emission estimation and dispersion modeling. The results indicate that on average, isolated calming measures increase carbon dioxide (CO2), carbon monoxide (CO) and nitrogen oxide (NOx) emissions by 1.50%, 0.33% and 1.45%, respectively across the entire network. Area-wide schemes result in a percentage increase of 3.84% for CO2, 1.22% for CO, and 2.18% for NOx. Along specific corridors where traffic calming measures were simulated, increases in CO2 emissions of up to 83% are observed. These increases are mainly associated with a change in vehicle drive-cycles through increased accelerations and decelerations. The results for air quality modeling suggest on average NO2 levels increase between 0.1% and 10% with respect to the base case. A high positive correlation of 0.7 between segment emissions of NOx and concentrations of NO2 is observed. Also, the effects of wind speed and direction are investigated in this thesis. The results show that higher wind speeds decrease NO2 concentrations on both sides of the roadway while winds orthogonal to the road increase the difference between concentrations on the leeward and windward sides with the leeward side experiencing higher levels. The effect of different measures on traffic volumes is also investigated and moderate decreases in areas that have undergone traffic calming are observed. Finally, the results show that speed bumps result in higher emission levels and poorer near-roadway air quality than speed humps. / Cette thèse porte sur le développement d'une simulation microscopique de la circulation et des émissions de véhicules ainsi qu'une modélisation de la dispersion atmosphérique qui vise à quantifier les effets de différents types de mesures d'apaisement de la circulation sur les émissions et la qualité de l'air. Cette analyse est conduite à la fois au niveau de liens spécifiques et au niveau du réseau à travers plusieurs scénarios de modélisation. La zone d'étude se situe à Montréal, Canada, où un modèle de simulation de trafic pour un quartier urbain dense est étendu avec des capacités d'estimation des émissions de véhicules et modélisation de la dispersion des polluants de l'air.Les résultats indiquent que, en moyenne, les mesures d'apaisement isolées augmentent les émissions de dioxyde de carbone (CO2), monoxyde de carbone (CO) et oxydes d'azote (NOx) de 1.50%, 0.33% et 1.45%, respectivement sur l'ensemble du réseau. Les mesures étendues sur plusieurs corridors augmentent de 3.84% les émissions de CO2, 1.22% de CO, et 2.18% de NOx. Le long des corridors spécifiques où des mesures de modération de la circulation ont été simulées, des augmentations d'émissions de CO2 allant jusqu'à 83% sont observées. Ces augmentations sont principalement associées à des changements de cycles d'accélération et de décélération. Les résultats de la modélisation de la qualité de l'air, suggèrent en moyenne que les niveaux de NO2 augmentent entre 0.1% et 10% par rapport au scénario de référence. Une corrélation positive de 0.7 entre les émissions de NOx et de concentrations de NO2 est observée. En outre, les effets de la vitesse et direction du vent sont étudiés. Les résultats démontrent que des vitesses du vent plus élevées réduisent les concentrations de NO2 des deux côtés de la chaussée alors que des vents perpendiculaires à la route d'augmentent la différence entre les concentrations des deux côtés de la route avec des niveaux plus élevés pour le côté situé en amont du vent. L'effet de l'apaisement de la circulation est également étudié sur les volumes de trafic et des diminutions modérées dans les zones qui ont subi l'apaisement sont observées. Enfin, les résultats démontrent que différents types de mesures d'apaisement ont des effets différents sur les émissions et la qualité de l'air.

Free surface vortices at low-head hydropower intakes can harm plant performance or cause premature failure of mechanical components by inducing unsteady or non-uniform flow or by entraining air, ice or floating debris down towards the turbines. Laboratory-scale physical modelling to assess vortex activity in proposed intakes is effective and remains the standard practice in industry, but it is costly and uncertainty remains as to how viscosity, turbulence and surface tension influence the translation of observed vortex characteristics from the laboratory model to the full-scale intake. Computational fluid dynamics (CFD) has been proposed as a potentially cheaper alternative without scale effects, but it requires further validation. This work sheds additional light on scale effects in laboratory-scale models and assesses the ability of a widely used commercial CFD package to predict vortex characteristics within the constraints of the hydraulic engineering context. A physical laboratory-scale model of a simplified intake is constructed with piers that produce vortices in their wake and that roughly resemble those that support trash racks at hydropower intakes. Instantaneous measurements of the three-dimensional velocity field inside the vortex are taken over a range of vortex intensities produced by eight operating conditions, with simultaneous recording of the free surface depression. The collected data are used to adapt Burgers's vortex model to link vortex characteristics (the characteristic radius, the bulk circulation, the depth and shape of the free surface depression, and the size of the largest floating particles entrained) to the operating conditions and intake geometry. The resulting model is then used to examine how viscosity, turbulence and surface tension influence vortex characteristics and their scaling behaviour. Finally, three operating conditions documented experimentally are numerically modelled using CFD with asimplified custom turbulence modelling strategy. The experimental results indicate that the axial profile of axial velocity in the vortex core, in combination with effective radial diffusivity due to viscosity and/or turbulence, plays a key role in determining the vortex characteristic radius. The magnitude of surface tension effects is shown to be relatively easily predicted and possibly far less important than scale effects associated with viscosity and turbulence. The CFD results further support the conclusion that modelling turbulence in interaction with the vortices remains one of the principal hurdles to overcome in predicting vortex characteristics at intakes in an industrial context. / La présence de tourbillons à l'amont de prises d'eau de centrales hydroélectriques à basse chute peut nuire à la performance de la centrale ou causer le bris prématuré de composants mécaniques, en provoquant des conditions d'écoulement non uniformes ou en entraînant de l'air, de la glace ou des débris flottants vers les turbines. Les modèles physiques à échelle réduite sont efficaces pour évaluer la présence de tourbillons à l'amont de prises d'eau proposées et ce mode d'évaluation demeure la pratique courante en industrie. C'est par contre une technique coûteuse et des incertitudes demeurent quant à l'influence de la viscosité, la turbulence et la tension superficielle sur le transfert des caractéristiques de tourbillons observés en modèle de laboratoire vers l'échelle de la centrale à grandeur nature. L'analyse numérique de dynamique des fluides (CFD) est souvent proposée comme alternative moins coûteuse et sans les effets d'échelle, mais le besoin d'une évaluation plus détaillée demeure. Le travail présenté ici apporte des nouvelles idées sur les effets d'échelle dans les modèles physiques à échelle réduite et évalue la capacité d'un logiciel commercial de CFD couramment utilisé pour prédire les caractéristiques de tourbillons dans les limites du contexte de génie hydraulique. Un modèle physique simplifié d'une prise d'eau à échelle réduite est construit avec des piliers provoquant un décollement qui génère des tourbillons. Ces piliers reproduisent approximativement ceux qui retiennent les grilles qui filtrent les gros débris dans les centrales hydroélectriques. Des mesures tridimensionnelles du champ de vitesse instantané sont collectées à l'intérieur des tourbillons de diverses intensités produits par huit conditions d'exploitation étudiées, avec enregistrement simultané de la dépression de la surface libre produite par le tourbillon. Les données ainsi collectées sont utilisées pour adapter le modèle de vortex de Burgers afin de lier les caractéristiques des tourbillons (le rayon caractéristique, la circulation totale, la profondeur et la forme de la dépression de la surface libre, et la dimension des plus grandes particules flottantes entraînées par le tourbillon) à la géométrie de la prise d'eau et aux conditions d'exploitation. Ce modèle adapté est ensuite utilisé pour examiner l'influence de la viscosité, de la turbulence et de la tension superficielle sur les caractéristiques des tourbillons et les lois de changement d'échelle. Enfin, trois conditions d'exploitation documentées expérimentalement sont simulées par CFD en utilisant une stratégie simplifiée de modélisation de turbulence adaptée pour cette étude. Les résultats expérimentaux indiquent que le profil de vitesse axiale le long de l'axe du du tourbillon en son centre, en combinaison avec la diffusivité radiale réelle due à la viscosité et/ou à la turbulence, a une influence déterminante sur la dimension du rayon caractéristique du tourbillon. L'amplitude des effets de tension superficielle peut être prédite relativement facilement et serait possiblement beaucoup moins importante que l'amplitude des effets d'échelle liés à la viscosité et à la turbulence. Les résultats des simulations par CFD renforcent la conclusion que la modélisation de la turbulence en interaction avec les tourbillons demeure un des obstacles principaux à surmonter afin de pouvoir prédire les caractéristiques de tourbillons aux prises d'eau dans un contexte industriel.

<p> Over the past few decades, there have been issues of poor fatigue performance (the main failure mechanism) of the welded, tube-to-transverse plate connections within sign support structures. Review of the literature has indicated that a considerable amount of research has been devoted to identifying the structural response characteristics of these signs. Others have tried to identify how these connections may be repaired, retrofitted or simply better designed to sustain longer fatigue lives. However, little attention has been given to using a systematic reliability-based approach to assess the risk of fatigue-induced fracture in these structures. </p><p> Using a reliability-based approach to solve structural engineering problems requires a fundamental knowledge of the uncertainty associated with three variables: resistance, demand and modeling error. The present research effort has focused on systematically quantifying this uncertainty. The procedure utilizes statistical parameters determined from probability frequency distributions generated for each of the three variables. Resistance is defined by the fatigue life of the connection, demand is defined by the wind loading (buffeting-type only) and modeling error is evaluated using high-fidelity finite element analysis (FEA) with comparison to measured data from a field monitoring system. </p><p> This research effort develops a reliability-based approach for prescribing inspection intervals corresponding to user-specified levels of fatigue-induced fracture risk. The resulting level of risk for a particular structure is dependent upon its geographical location, the type of connection it contains, the orientation of its mast-arm relative to north and the number of years it has been in service. The results of this research effort indicate that implementation of state-of-the-art reliability-based assessment procedures can contribute very valuable procedures for assigning inspection protocols (<i>i.e.</i> inspection intervals) that are based upon probabilities of finding fatigue-induced cracking in these structures. The engineering community can use the results of this research effort to establish inspection intervals based upon risk and thereby better align inspection needs with limited fiscal and human resources.</p>

<p> In many structural concrete applications, loaded areas are surrounded by steel reinforcement or additional concrete in order to triaxially confine the region. This confinement effectively increases the local bearing strength and ductility. However, this is typically accomplished at the expense of increasing steel congestion and/or providing an inefficient amount of additional concrete. One way of alleviating these complications may be by confining loaded areas with steel fiber reinforced concrete (SFRC). Provisions within ACI 318-11 allow for an increase in the effective bearing strength of concrete based on the ratio of the loaded area to the overall area. However, there has not been a study of the confining capability of SFRC when the loaded area is smaller than the surrounding area. The study presented in this thesis addresses this need. </p><p> The current research project examines the influence of SFRC on the bearing strength of triaxially confined nodal regions. As part of this evaluation, twenty-four 12..24-inch cylindrical specimens were loaded to failure through 6- and 3-inch diameter bearing plates. Experimental variables include transverse reinforcement ratios ranging between 0 and 0.80 percent, and steel fiber dosages between 0 and 1.5 percent by volume. Specimens were uniaxially loaded to failure while displacement and load data was recorded.</p>

<p> A photonic crystal fiber (PCF) long-period grating (LPG) humidity sensor has been developed with high sensitivity and selectivity for nondestructive detection of moisture ingression into structures that can potentially lead to corrosion. We have proposed two types of nanofilms to be coated on the surface of air channels in the grating region of the fiber using electrostatic self-assembly deposition processing. The primary nanofilm does not affect LPG properties such as resonance wavelength or transmission intensity which can impact sensing characteristics; however it increases the sensitivity by changing the refractive index of the surrounding material. The secondary nanofilm is used for selectively adsorbing analyte molecules of interest. The experimental results reveal that, compared to the conventional fiber LPGs and exterior nanofilm-coated PCF-LPG, the interior nanofilm-coated PCF-LPG humidity sensors have higher resonance intensity change of 0.00022%/10^-3dBm at relative humidity (RH) of 38% and average wavelength shift of 0.0007%/pm in range of 22% to 29%. The proposed sensor shows excellent thermal stability as well.</p>

<p> This dissertation introduces three new methodologies to improve traffic signal operations of Diverging Diamond Interchanges (DDIs). Methodology one applies to a DDI without signals for left-turns from the freeway off-ramp. This methodology combines Webster's method and the specific characteristics of a DDI to determine traffic signal operation parameters such as cycle length, phasing splits, and phasing sequence. Comparing to methodology one, methodology two can handle more general and complex cases. Both methodologies can be implemented at a DDI by one traffic controller and operate successfully for a variety of controller types including pre-timed, fully actuated, and coordinated actuated control. Methodology three, also called proposed operation 3, combines Genetic Algorithm and a professional simulation tool such as VISSIM to search for the optimal operations for DDIs based on the phasing scheme of methodology 1 or 2. </p><p> As a case study, methodology two is comprehensively studied based on a proposed DDI located at Moana Lane and U.S. 395, in Reno, Nevada. Through testing in a hardware-in-the-loop platform, this methodology can operate successfully for pre-timed, fully actuated, and coordinated actuated traffic signal controls. </p><p> Microscopic simulation models were developed to evaluate the traffic signal operation of each scenario. The simulation results revealed that proposed methodology 2 reduces average delay by 17% in the morning (AM) peak hour and 28% in the afternoon (PM) peak hour at the Moana DDI, when compared to the methodology presented by staff from the City of Reno, NV. The average total delays of different cycle lengths show that the optimal cycle length changes with the variation of saturation flow ratios at this DDI. The simulations illustrated that the performances of the same traffic signal operation varied when it was applied to a variety of traffic volume distributions among routes. Therefore, developing a traffic signal operation for a DDI based on its traffic volume distributions on routes, instead of turning movement volumes, is necessary. The results also indicate that the range of signal operation performance on a variety of traffic volume distributions on routes reduces when the space between the two crossovers intersections of a DDI increases.</p>

<p> There are two primary methods to investigate the response of reinforced concrete (RC) structural components. Experimental testing method has been widely used to study the behavior of RC members under different loading conditions, while the results obtained have a high degree of accuracy, it is sometimes very time consuming and also can be very costly. Finite element (FE) analysis method as a numerical based solution technique, also is widely used to analyze behavior of structural components, and although the use of this method was very time consuming in several decades ago, however utilizing existing powerful software and hardware capabilities has made it easier nowadays. </p><p> An investigation is conducted on two-way RC beam-supported slabs using FE analysis technique to study their inelastic behavior when subjected to in-plane and out-of-plane loads. Two-way RC slab models were constructed for solid slab panels tested by Nakashima (1981) and the results obtained from FE analysis were compared with the experimental data. </p><p> Non-linear 3-D ANSYS models with smeared and discrete reinforcing steel were used. The obtained results from FE method indicated an acceptable agreement with experimental data. The verified FE model then was used to investigate the effect of floor openings on inelastic behavior of two-way RC slabs subjected to in-plane and out-of-plane loads. The opening was placed in the mid-region of the slab panel, where its size was varied from 6.25% to 25% of the panel area. To satisfy the strength requirements Section 13.4 of the American Concrete Institute code (ACI 318-11), additional reinforcement were placed in the slab around the opening. The results are presented and discussed. </p><p> It is observed that the failure mechanism changes in slab with larger opening where the steel yielding starts in rebars at the opening corners, and the failure damage at the ultimate load is more distributed. It is concluded that as the opening size increases, effect of out-of-plane (gravity) load on in-plane load capacity reduction of the slab decreases while the ultimate displacement at failure increases.</p>

<p> In view of the limitations of univariate statistics for studying construction accidents, a multivariate approach was undertaken using crosstabulation analysis and logistic regression.</p><p> Heavy construction equipment accidents related data for four type of equipment; backhoe, bulldozer, excavator and scraper were incorporated in the study using categorical variables. Degree of injury indicating the severity of accident outcome (fatal vs. nonfatal) was selected as the dependent variable, and a variety of factors potentially affecting the outcome comprised the independent variables. Cross tabulation results enabled the understanding and evaluation of associations between the research variables, while logistic regression yielded predictive models that helped describe accident severity in terms of the contributing factors. Factors increasing or decreasing the odds of accident severity (degree of injury) in the presence or absence of various factors were identified and quantified. It was concluded that multivariate analysis serves as a much more powerful tool than univariate methods in eliciting information from construction accident data. Union status of workers and the safety training they were provided according to OSHA guidelines vastly affect the degree of injury and lessen the odds of fatality.</p>

<p> Estimation of long-term performance (or life) is a critical pavement design concern. Though wheel wander is not routinely addressed in pavement designs, its consideration provides for a more realistic and economical design. The procedures in MEPDG and CalME to address the wheel wander recommend the use of normal distributions for transverse wheel wander. These procedures are based on dividing the wheel wander distribution into a number of segments (say five) of equal areas. Such approaches suffer from a major limitation that the selection of equal segments is arbitrary, can lead to biased results. </p><p> The study reported here covered a variety of pavement factors that significantly affect pavement performance. These factors included are: (1) pavement layer configuration (thin and thick); (2) pavement material properties (conventional and polymer-modified); (3) tire configurations (dual and wide-base); (4) pavement temperature (T = 70&deg;F and T = 104&deg;F); and (5) vehicle operating conditions (braking and non-braking). A major contribution of this thesis is to provide valuable design information on the relative importance of these factors on the prediction of pavement life. </p><p> A Monte-Carlo simulation scheme that addressed the role wheel wander on pavement response and performance has been developed. Since the traffic lanes are of limited width (about 12 ft.), the trial values of wheel wander was limited to &plusmn; 21 in about the centerline of the traffic lane. The proposed Monte-Carlo scheme provided cumulative distribution functions (CDFs) for all the important responses and they in turn were used in the estimation pavement performance (or life). This study only focused on the impact of wheel wander on HMA failure modes. Required traffic-induced pavement strain database needed in the HMA distress investigations were developed using UNR's 3D-Move model. Three methods were used to evaluate the pavement performance (of life). </p><p> These methods differ based on the value of the traffic-induced strains used in the performance equations. First method (Method 1) uses the maximum response strain, while the second method (Method 2) is the MEPDG approach. The Method 3 is based on the CDFs developed by the Monte-Carlo simulation scheme described in this thesis. The CDFs were divided into a number of equal segments and the strains that correspond each of the segments were used with the performance equations. As many numbers of segments as needed can be considered, however for being consistent with MEPDG approach (Method 2), it was decided to use five segments. </p><p> Since the Method 1 uses the largest pavement response, the pavement life predicted by Method 1 is always lower and this may be interpreted as being over conservative. The Method 2 (MEPDG approach), though an important step forwards realistic modeling of long-term pavement performance, its arbitrary use of fixed five locations to define the wheel wander can be biased and therefore, questionable. The Method 3 is statically-based and uses many trials for wheel wander locations to model the vehicle wander. Therefore, it takes into account in a more realistic manner the entire variation in traffic-induced strain on the transverse plane. Such an approach is considered more appealing to pavement engineers and researchers. </p><p> In summary, pavement design information presented in this thesis are in the form of datasets that the pavement engineers researchers can use to assess the sensitivity of many important factors that affect long-term pavement performance. Neither interpretation nor scrutiny of the design information has been attempted. Instead, the thesis outlines elaborate details on a three-step approach used to develop such design guidelines.</p>

<p> More production equals more waste, more waste creates environmental concerns of toxic threat. An economical viable solution to this problem should include utilization of waste materials for new products and one that minimizes the heavy burden on the nation's landfills. The importance of recycling is huge because it saves natural resources, saves energy, reduces solid waste, reduces air and water pollutants, and reduces greenhouse gases. The construction industry can start being aware of and take advantage of the benefits of using waste and recycled materials. Studies have investigated the use of acceptable waste, recycled, and reusable materials and methods. The use of swine manure, animal fat, silica fume, roofing shingles, empty palm fruit bunch, citrus peels, cement kiln dust, fly ash, foundry sand, slag, glass, plastic, carpet, tire scraps, asphalt pavement, and concrete aggregate in construction is becoming increasingly popular due to the shortage and increasing cost of raw materials. In this study a survey was conducted to find out the current practices of the uses of waste and recycled materials in the construction industry. The results proved that companies are not aware of what's available to use or the quality of the materials performance or the cost savings or any other benefits including environmental. Based from the results of the survey the following research was conducted to create better documentation for Green Building, connecting researches and contractors with an overview of what recycled materials are available for different construction applications.</p>