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Momeni, Hojr. "Identifying effective geometric and traffic factors to predict crashes at horizontal curve sections." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32821.
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Doctor of PhilosophyDepartment of Civil Engineering
Sunanda Dissanayake
Malgorzata J. Rys
Driver workload increases on horizontal curves due to more complicated navigation compared to navigation on straight roadway sections. Although only a small portion of roadways are horizontal curve sections, approximately 25% of all fatal highway crashes occur at horizontal curve sections. According to the Fatality Analysis Reporting System (FARS) database, fatalities associated with horizontal curves were more than 25% during last years from 2008 to 2014, reinforcing that investigation of horizontal curve crashes and corresponding safety improvements are crucial study topics within the field of transportation safety. Improved safety of horizontal curve sections of rural transportation networks can contribute to reduced crash severities and frequencies. Statistical methods can be utilized to develop crash prediction models in order to estimate crashes at horizontal curves and identify contributing factors to crash occurrences, thereby correlating to the primary objectives of this research project. Primary data analysis for 221 randomly selected horizontal curves on undivided two-lane two-way highways with Poisson regression method revealed that annual average daily traffic (AADT), heavy vehicle percentage, degree of curvature, and difference between posted and advisory speeds affect crash occurrence at horizontal curves. The data, however, were relatively overdispersed, so the negative binomial (NB) regression method was utilized. Results indicated that AADT, heavy vehicle percentage, degree of curvature, and long tangent length significantly affect crash occurrence at horizontal curve sections. A new dataset consisted of geometric and traffic data of 5,334 horizontal curves on the entire state transportation network including undivided and divided highways provided by Kansas Department of Transportation (KDOT) Traffic Safety Section as well as crash data from the Kansas Crash and Analysis Reporting System (KCARS) database were used to analyze the single vehicle (SV) crashes. An R software package was used to write a code and combine required information from aforementioned databases and create the dataset for 5,334 horizontal curves on the entire state transportation network. Eighty percent of crashes including 4,267 horizontal curves were randomly selected for data analysis and remaining 20% horizontal curves (1,067 curves) were used for data validation. Since the results of the Poisson regression model showed overdispersion of crash data and many horizontal curves had zero crashes during the study period from 2010 to 2014, NB, zero-inflated Poisson (ZIP), and zero-inflated negative binomial (ZINB) methods were used for data analysis. Total number of crashes and severe crashes were analyzed with the selected methods. Results of data analysis revealed that AADT, heavy vehicle percentage, curve length, degree of curvature, posted speed, difference between posted and advisory speed, and international roughness index influenced single vehicle crashes at 4,267 randomly selected horizontal curves for data analysis. Also, AADT, degree of curvature, heavy vehicle percentage, posted speed, being a divided roadway, difference between posted and advisory speeds, and shoulder width significantly influenced severe crash occurrence at selected horizontal curves. The goodness-of-fit criteria showed that the ZINB model more accurately predicted crash numbers for all crash groups at the selected horizontal curve sections. A total of 1,067 horizontal curves were used for data validation, and the observed and predicted crashes were compared for all crash groups and data analysis methods. Results of data validation showed that ZINB models for total crashes and severe crashes more accurately predicted crashes at horizontal curves. This study also investigated the effect of speed limit change on horizontal curve crashes on K-5 highway in Leavenworth County, Kansas. A statistical t-test proved that crash data from years 2006 to 2012 showed only significant reduction in equivalent property damage only (EPDO) crash rate for adverse weather condition at 5% significance level due to speed limit reduction in June 2009. However, the changes in vehicles speeds after speed limit change and other information such as changes in surface pavement condition were not available. According to the results of data analysis for 221 selected horizontal curves on undivided two-lane highways, tangent section length significantly influenced total number of crashes. Therefore, providing more information about upcoming changes in horizontal alignment of the roadway via doubling up warning sings, using bigger sings, using materials with higher retroreflectivity, or flashing beacons were recommended for horizontal curves with long tangent section lengths and high number of crashes. Also, presence of rumble strips and wider shoulders significantly and negatively influenced severe SV crashes at horizontal curve sections; therefore, implementing rumble strips and widening shoulders for horizontal curves with high number of severe SV crashes were recommended.
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Trumpoldt, Julie Marie. "Development of a Tool to Calculate Appropriate Advisory Speeds on Horizontal Curves." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/71768.
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Horizontal curves are a contributing factor for numerous deaths on roadways. The curve characteristics dictate the severity of the curve and require the driver to be more attentive while driving. To address this issue, advisory speeds are posted on horizontal curves to warn drivers to slow down for their safety. There are six main procedures to assign advisory speeds. This paper focuses on two of these methods, finds a connection between the two, and develops an Android Application that can be used to determine an advisory speed for a curve. In this work, a brief summary of the six existing methods for advisory speed assignment are discussed. Pros and cons are included for each for comparison purposes. Next, two of these methods are highlighted by applying them in the field. Data is collected and a relationship between them is determined. Using this relationship, an Android Application is created and the various details of the design process are described. This Application, called CurveAdvisor, allows the user to assign the appropriate advisory speed on a desired horizontal curve. An analysis is then conducted to test the effectiveness of CurveAdvisor. Results indicate that CurveAdvisor is successful in many cases. Finally, contributions and suggestions for future work are included.Master of Science
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Browning, Joseph Stuart. "Developing a Method to Identify Horizontal Curve Segments with High Crash Occurrences Using the HAF Algorithm." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8809.
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Crashes occur every day on Utah’s roadways. Curves can be particularly dangerous as they require driver focus due to potentially unseen hazards. Often, crashes occur on curves due to poor curve geometry, a lack of warning signs, or poor surface conditions. This can create conditions in which vehicles are more prone to leave the roadway, and possibly roll over. These types of crashes are responsible for many severe injuries and a few fatalities each year, which could be prevented if these areas are identified. This highlights a need for identification of curves with high crash occurrences, particularly on a network-wide scale. The Horizontal Alignment Finder (HAF) Algorithm, originally created by a Brigham Young University team in 2014, was improved to achieve 87-100 percent accuracy in finding curved segments of Utah Department of Transportation (UDOT) roadways, depending on roadway type. A tool was then developed through Microsoft Excel Visual Basic for Applications (VBA) to sort through curve and crash data to determine the number of severe and total crashes that occurred along each curve. The tool displays a list of curves with high crash occurrences. The user can sort curves by several different parameters, including various crash rates and numbers of crashes. Many curves with high crash rates have already been identified, some of which are shown in this thesis. This tool will help UDOT determine which roadway curves warrant improvement projects.
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Doder, Dejan. "Experimental analysis of the pressure characteristic curve of a forced convection boiling flow in single horizontal channel." Thesis, Norges Teknisk-Naturvitenskaplige Universitet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20917.
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Forced convection boiling flow, often referred to as two-phase flow, is a common phenomenon which occurs in many industrial processes. The relationship between the total pressure drop in a channel containing two-phase flow and the mass flux of the flow is known as the pressure characteristic curve. If any part of pressure characteristic curve contains a negative slope, flow instabilities might occur in the channel. Flow instabilities are unwanted because they can reduce the efficiency of the industrial process. In this study experimental work has been done to analyze the behavior of the pressure characteristic curve in two-phase flow by applying a sensitivity analysis. The parameters which were analyzed in the sensitivity analysis were inlet pressure, subcooling temperature, total heating power and heating power distribution. Also, experimental results from this study were compared with the results from a numerical study of the characteristic pressure curve of two-phase flow [1].The experimental study showed that all the analyzed parameters influence the behavior of the pressure characteristics curve. The comparison with the numerical study showed the same trends for behavior for the pressure characteristic curve for all analyzed parameters except for the total heating power.From the analyzed parameters it was shown that the inlet pressure has the largest relative influence on the behavior of the pressure characteristic curve compared to the other parameters. Lowering the inlet pressure leads to the largest change in the mass flux range where flow instabilities can occur. Lowering the inlet pressure also leads to the largest change in the negative slope the pressure characteristic curve.
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Gong, Huafeng. "OPERATING SPEED PREDICTION MODELS FOR HORIZONTAL CURVES ON RURAL FOUR-LANE NON-FREEWAY HIGHWAYS." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/562.
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One of the significant weaknesses of the design speed concept is that it uses the design speed of the most restrictive geometric element as the design speed of the entire road. This leads to potential inconsistencies among successive sections of a road. Previous studies documented that a uniform design speed does not guarantee consistency on rural two-lane facilities. It is therefore reasonable to assume that similar inconsistencies could be found on rural four-lane non-freeway highways. The operating speed-based method is popularly used in other countries for examining design consistency. Numerous studies have been completed on rural two-lane highways for predicting operating speeds. However, little is known for rural four-lane non-freeway highways. This study aims to develop operating speed prediction models for horizontal curves on rural four-lane non-freeway highways using 74 horizontal curves. The data analysis showed that the operating speeds in each direction of travel had no statistical differences. However, the operating speeds on inside and outside lanes were significantly different. On each of the two lanes, the operating speeds at the beginning, middle, and ending points of the curve were statistically the same. The relationships between operating speed and design speed for inside and outside lanes were different. For the inside lane, the operating speed was statistically equal to the design speed. By contrary, for the outside lane, the operating speed was significantly lower than the design speed. However, the relationships between operating speed and posted speed limit for both inside and outside lanes were similar. It was found that the operating speed was higher than the posted speed limit. Two models were developed for predicting operating speed, since the operating speeds on inside and outside lanes were different. For the inside lane, the significant factors are: shoulder type, median type, pavement type, approaching section grade, and curve length. For the outside lane, the factors included shoulder type, median type, approaching section grade, curve length, curve radius and presence of approaching curve. These factors indicate that the curve itself does mainly influence the drivers speed choice.
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Ullah, Irfan. "Caracterização da subsuperfície rasa através da curva da razão espectral H/V e da inversão conjunta das curvas de dispersão e elipticidade." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/14/14132/tde-04062018-101840/.
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A destruição causada por um terremoto depende de muitos fatores, como características e profundidade da fonte, magnitude, distância epicentral e da configuração geológica da área. A destruição causada devido à configuração geológica da área é denominada como efeito local. A modelagem do efeito local implica na determinação do tempo e nível de vibração e do efeito de amplificação do deslocamento. As propriedades elásticas dos materiais geológicos (velocidade das ondas de compressão e de cisalhamento, densidade, espessura da camada de solo, etc.) podem ser obtidas por diversos métodos geofísicos. O conhecimento dessas propriedades elásticas ajuda a melhor projetar as infraestruturas e reduzir as chances de danos. Este procedimento é denominado de microzoneamento. Os parâmetros mais importantes para realizar o microzoneamento são as espessuras dos sedimentos que recobrem o embasamento e o perfil das velocidades das ondas S (cisalhamento). Esses dois parâmetros são adequadamente caracterizados pelo uso de várias técnicas geofísicas como perfilagens em furos de sondagem, reflexão e refração sísmica. Esses métodos geofísicos trazem algumas restrições como a necessidade da execução de um furo, emprego de fontes sísmicas artificiais que muitas vezes são dispendiosas e por vezes de uso restrito em áreas urbanas, além de muitas vezes estarem limitadas a investigações de apenas algumas dezenas de metros. Os métodos que substituíram esses métodos geofísicos convencionais nas últimas décadas são a análise do ruído sísmico produzido por fontes naturais e culturais. Este ruído sísmico ambiental pode ser registrado com menor custo e esforço e com boa cobertura lateral. Várias técnicas que se utilizam do ruído sísmico podem ser empregadas, no entanto, aquela que obteve maior atenção nos últimos anos é a técnica da razão do espectro horizontal sobre o espectro vertical da onda de superfície (H/V). A curva da razão espectral H/V é uma ferramenta rápida, fácil e de baixo custo para a caracterização da subsuperfície rasa. Existem vários estudos realizados sobre o tema que tentaram cobrir todos os aspectos e problemas associados ao método. Aqui neste estudo são aprofundados alguns aspectos ainda não avaliados em detalhe. Diferentes procedimentos para a modelagem e as associações entre os fenômenos físicos envolvidos e as características da curva H/V são discutidos e os resultados numéricos desses estudos são comparados com informações extraídas de perfis de sondagens de um dos locais estudados. O pico e a forma da curva H / V são modelados para encontrar o desvio na frequência de pico a partir da frequência de ressonância da onda de cisalhamento considerando diferentes campos de onda em torno do pico, assim como sua relação com a forma dominante da curva. A frequência de pico das curvas H/V é utilizada para estimar a relação entre a frequência a espessura através de análise de regressão. O estudo mostra que a curva de dispersão obtida a partir de um ensaio MASW pode ser usada para estimar a velocidade da onda S a um metro de profundidade e sua tendência de aumento com a profundidade. Esses valores podem ser usados para estimar a relação frequência-espessura para uma área. Esses resultados são comparados com a relação frequência-espessura derivada experimentalmente para a mesma área. A sensibilidade da forma da curva H/V à estrutura de velocidade do meio é analisada através de duas técnicas de modelagem (elipticidade da onda Rayleigh e campo difuso baseado na curva H/V). Diferentes partes da curva H/V são invertidas visando avaliar qual a parte da curva H/V contém as informações mais importantes sobre a estrutura subterrânea. As lições aprendidas dessas análises são aplicadas a três dados experimentais de locais distintos. As ondas Love podem contaminar o resultado da curva H/V. Duas técnicas diferentes para remover o efeito das ondas amorosas são discutidas. Em seguida, são discutidos os resultados da inversão conjunta das curvas de dispersão e da curva H/V após remoção do efeito da onda Love, ou seja, a curva de elipticidade. Alguns aspectos novos da técnica H/V são discutidos no final.The destruction caused by an earthquake at a site depends on many factors like source characteristics such as magnitude, epicentral distance from the site, depth of the source, and on the geological setting of the area. The destruction caused due to the geological setting of an area is termed as site effect. To model the site effect of an area is to determine the shaking level longevity and its displacement amplification. The elastic properties (shear and compressional wave velocities, density, thickness of soil layer, etc.) of the site are required to find out by employing various geophysical procedures. The knowledge of these elastic properties help in better designing the infrastructure, which reduces the chances of destruction caused by a local geological setting due to an earthquake occurrence. This procedure is widely termed as microzonation. The most important parameters for the microzonation are the thickness of soft sediments over the seismic bedrock and its shear wave velocity profile. These two parameters are properly characterized by employing various geophysical techniques like borehole measurement, seismic reflection and seismic refraction. The conventional geophysical methods bring some hindrance to the picture such as, the drilling of a borehole and artificial seismic sources deployment for the reflection and refraction survey, which are both expensive and time consuming, difficult or even in some case impossible to implement in urbanized environment, the investigation is depth limited to few tens of meter. The methods which replaced this conventional geophysical method from the last decades or so is the analysis of Earth vibration caused by the seismic noise which is produced by both natural and cultural sources. This ambient seismic noise can be recorded with less cost and effort with good lateral coverage. Various seismic noise techniques are employed for this job; however, the one which got the most attention in recent years is the horizontal over vertical spectral ratio (H/V) technique. The H/V spectral ratio curve is a fast easy and cheap tool for the near-subsurface characterization. There are various study performed on the topic which has tried to cover almost all the aspects and problems associated with the method. Here in this study, we try to detail the aspects of this technique, which are not been evaluated fully. The different modelling procedures presented to model and physically link the H/V curve with some physical phenomenon will be discussed and its numerical result with the experimental H/V curve will be compared for a borehole test site. The peak and the shape of the H/V curve will be modelled to find its peak frequency deviation from the shear wave resonance frequency by considering different wave-field around the peak. Similarly, the shape dominancy of the H/V curve linkage will be find out. The peak frequency of the H/V curve is used to estimate the thickness-frequency relation by regression analysis. Here we will show that the dispersion curve obtained from multi-channel analysis of surface waves (MASW) can be used to estimate the velocity at one meter and the shear wave velocity increase trend with depth. These values can be used to estimate the thickness frequency relation for an area and its result will be compared with the experimentally derived thickness-frequency relationship for the same area. The sensitivity of the H/V curve shape to the subsurface velocity structure will find out for two main modelling techniques (Rayleigh wave ellipticity and diffused field based H/V curve). The different parts of the H/V curve are inverted (back modelled) to find out the part of H/V curve which is carrying the most important information about the subsurface structure. The lesson learned from all this analysis will be applied to experimental data of three different sites. The Love waves might contaminate the result of the H/V curve. Two different techniques to remove their effects will be discussed. Then, the joint inversion result of the dispersion and this Love effect removed H/V for more precisely ellipticity curve is discussed. Some new aspects of the H/V curve technique are also discussed at the end.
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Ara?jo, Arthur Gomes Dantas de. "Provas de carga est?tica com carregamento lateral em estacas escavadas h?lice cont?nua e cravadas met?licas em areia." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/14852.
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Previous issue date: 2013-12-10An experimental study has been conducted to investigate the behavior of continuous flight auger (cfa) bored piles and metalic driven H-section piles under lateral loading in cohesionless soils. The piles were tested in two different areas at the same site. Both areas consisted of a 3-m thick compacted superficial fill of pure fine sand, underlain by layers of naturally occurring pure fine-thick sand. Fills are differentiated by the relative densities which were compressed, 45% e 70%, respectively. Each area received one identical pair of cfa piles and two identical pairs of H-piles. A static lateral loading test was performed in each pair of piles. In this work, the pile load test results are reported and interpreted. The horizontal coefficient of subgrade reaction was determined from the results of the loading tests and compared with values determined by correlations based on penetration resistance index of SPT tests (NSPT). p-y formulations describing the static behavior of the piles were applied to the problem under evaluation. Back Analyses were made through theoretical and experimental p-y curves for obtaining input parameters for the analytic models, among which the coefficient of horizontal reaction. The soil pile system horizontal loading at rupture was determined by the theoretical methods and the results were compared with the experimental results, checking its validity
Um estudo experimental foi realizado para investigar o comportamento de estacas escavadas h?lice cont?nua e estacas cravadas met?licas submetidas a carregamentos laterais em areia. As estacas foram ensaiadas em duas ?reas diferentes no mesmo local. Ambas as ?reas eram compostas por um aterro superficial de 3 m de espessura de areia fina, seguido de camadas naturais de areia fina a grossa. Os aterros diferenciam-se pela densidade relativa com que foram compactados, 45% e 70%, respectivamente. Cada ?rea recebeu um par id?ntico de estacas h?lice cont?nua e dois pares id?nticos de estacas met?licas com perfil H . Em cada par de estacas foi executada uma prova de carga est?tica. Neste trabalho, os resultados das provas de carga s?o apresentados e interpretados. O coeficiente de rea??o horizontal do solo foi determinado atrav?s dos resultados das provas de carga e comparado com valores obtidos a partir de correla??es baseadas no ?ndice de resist?ncia ? penetra??o do ensaio SPT (NSPT). Curvas p-y foram constru?das para prever o comportamento de estacas submetidas a carregamentos horizontais. Retro an?lises foram efetuadas atrav?s das curvas p-y te?ricas e experimentais para obten??o de par?metros de entrada para os modelos anal?ticos, dentre os quais o coeficiente de rea??o horizontal. A carga de ruptura do sistema solo estaca foi determinada atrav?s de m?todos te?ricos e os resultados foram comparados com os resultados experimentais, verificando sua validade
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Saeidi, Ali. "La vulnérabilité des ouvrages soumis aux aléas mouvements de terrains ; développement d'un simulateur de dommages." Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL003N/document.
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L’objectif de cette thèse a été de concevoir et développer un simulateur de dommages permettant d’étudier la vulnérabilité d’un territoire soumis à des aléas de mouvements de terrains associés à la présence d’exploitations souterraines. Ce développement repose sur la combinaison d’une méthode de prévision des affaissements miniers, de fonctions de vulnérabilité pour l’évaluation des dommages et d’une base de données des bâtiments. L’enjeu scientifique est le développement de fonctions de vulnérabilité pour les bâtiments en zone d’affaissement minier. Ces fonctions sont comparables à celles utilisées vis-à-vis d’autres aléas comme les séismes et les tsunamis. On a développé et appliqué une méthodologie basée sur des simulations de type Monte-Carlo qui utilise les méthodes existantes d’évaluation des dommages dans les zones d’affaissement minier (méthodes empiriques ou analytiques). Elle permet de prendre en compte l’incertitude sur les paramètres géométriques et mécaniques du bâti. Afin de valider cette méthodologie, les dommages estimés par les fonctions vulnérabilité développées pour des bâtiments en maçonnerie du bassin ferrifère lorrain sont comparées aux dommages observés, consécutifs aux affaissements de 1996 à 1999 en Lorraine. Dans une étape suivante, la méthode des fonctions d’influence a été implémentée dans le simulateur avec certains développements permettant de tenir compte de la variabilité des angles d’influences et permettre le calcul des déformations horizontales du terrain. Les résultats de cette méthode sont validés sur un cas d’affaissement observé dans le bassin ferrifère de lorrain. Enfin, une approche probabiliste d’évaluation des dommages est implémentée pour tenir compte de différents scénarios d’affaissement possibles. L’application sur les bâtiments de la ville de Joeuf, permet d’illustrer les différents résultats obtenusThe objective of this thesis has been the design and the development of a damage simulator for evaluation of building damage in subsidence regions affected by undergrounds excavations. The simulator is combining a method for the subsidence prediction, vulnerability functions for assessment of building damage and a database of buildings. The scientific challenge is the development of vulnerability functions for buildings in subsidence regions. These functions are similar to those used for other hazards such as earthquakes and tsunamis. We then developed and applied a methodology based on Monte-Carlo simulations which involves existing methods of building damage assessment in subsidence area (empirical or analytical methods). It allows to take into account uncertainties on both geometrical and mechanical parameters of buildings. To validate this methodology, damages given by the vulnerability functions developed for masonry buildings in the Lorraine Iron ore field are compared to observed damages, resulting from subsidence from 1996 to 1999 in Lorraine. In a next step, the method of influence functions is implemented in the simulator with developments to take into account variability of the influence angles and to allow the calculation of horizontal ground strain. Results of this method are validated with a subsidence case study in the Lorraine iron ore field. Finally, a probabilistic approach to assess damage is implemented in the simulator to take into account different scenarios of possible subsidence. The application of the simulator on the buildings of the Joeuf city, allows to illustrate the different results
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Kovářová, Veronika. "Variantní řešení silnice I/57 v úseku Semetín-Bystřička." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226452.
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The subject of my thesis is a variant I/57 in the section Semetín-Bystřička. The proposed route of communication, was part of an existing communications maintained for its full utilization. Were drawn four proposed variants of the solution, 3 variants are trying their best to use existing communication Jablůnka the village, one suggested option B that leads outside the existing road.
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Čepil, Jiří. "Optimalizace návrhových prvků pozemních komunikací pomocí vlečných křivek vozidel." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-408021.
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The dissertation deals with application of simulated swept paths of vehicles to road designs. Using software which generates simulated swept paths makes new demands on the designer, but Czech regulations do not stipulate the appropriate method of applying swept paths. The theoretical part of the dissertation analyses the theory of how a vehicle moves when passing through a horizontal road curve and a method of calculating a necessary extent of widening the road. The practical part compares swept paths generated by various software programs and differences between them. In order to verify the shapes and dimensions of the swept paths generated, the swept path of a real vehicle was measured. This swept path was then compared with the one generated, and the differences between them were evaluated. One of the software programs was chosen as a reference program, and its output was applied to a road design pursuant to valid regulations. The results obtained within the dissertation were used to develop certified methodology titled: „Methodology of widening road lanes in horizontal curves and of application of vehicles’ swept paths “.
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Tomešek, Zdeněk. "Vyhledávací studie obchvatu města Hustopeče." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225418.
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This graduation thesis deals about researching study of by-pass road of city Hustopeče, district of Břeclav, Southmoravian region. This city passes main road number 425, which should be connected with the by-pass road. The by-pass road will be designed as road of category S9,5/70 and will be situated west of the city. Terrain is undulated and composed of agricultural parcels. The main purpose of this by-pass road is significant burden of region traffic.
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Aryal, Prabin. "Optimization of geometric road design for autonomous vehicle." Thesis, KTH, Byggvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-290030.
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These days most of the research related to autonomous vehicle technology focuses on vehicle technology itself and lesser on road infrastructure, including geometric design. This research project aims to lower the deficiency of research works required to make the optimized geometric road design for autonomous vehicle sustainable. In geometric design, significant concerns are designing the road geometrics such as lane width, the radius of horizontal curves, sag vertical curves and crest vertical curves, extra widening, setback distance, and intersection, making the road safer for the vehicles to travel comfortably.Road geometrics is widely designed using the stopping sight distance model, which provides sufficient time to avoid accidents and is efficient. Here in the research work, the stopping sight design model is used for autonomous vehicle technology. At first, the art of autonomous vehicle technology is studied, and a significant difference between autonomous vehicle technology and human-driven vehicle to apply stopping sight distance model is figured out. A literature study is also done for the geometric design of the road for the vehicle with the human driver and autonomous vehicle. The AASHTO model derived for the human-driven vehicle is used and modified for the autonomous vehicle, which gives the optimized geometric design for the autonomous vehicle. The Optimized geometric design parameter is designed individually in AutoCAD Civil 3D. Two road designs follow this in a random rural topography consisting of a normal road design for the vehicle with the human driver and a fully autonomous vehicle. Finally, the sustainability of optimized geometric design compared to road design for the human-driven vehicle is checked in terms of earthwork, pavement surface areas, and pavement materials volume. The result shows that the optimization of a geometric road design for autonomous vehicles is sustainable and extensive research is required.
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Wong, Yiik Diew. "Driver behaviour at horizontal curves." Thesis, University of Canterbury. Civil Engineering, 1989. http://hdl.handle.net/10092/7596.
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Studies relating accident occurrence to horizontal curve geometry indicate a strong association between the radius of horizontal curves and accident occurrence, but the individual effect of horizontal curvature on safety is still uncertain. The preponderance of human error as a contributory cause of accidents has led to a growing interest in research on driver behaviour. The human factor in road safety is discussed and literature on driver behaviour on horizontal curves is reviewed.
A study involving unobtrusive observation of driver behaviour at two curves (an isolated curve and a reverse curve) before and after realignment was carried out. Data on driver behaviour was collected by continuous video-recording of each subject vehicle as it moved through each curve. Lateral placement and speed data along the curve were extracted from the video record, and the path radius and sideway force coefficient at the mid-point of the curve were estimated. The observed driver behaviour is discussed.
The results of the study were checked against the underlying design assumptions, which are shown not to be completely and universally valid. The evaluation of the realignment, based on driver behaviour and the sideway force coefficient, and the accident records show that there was an overall improvement in the margin of safety at all the curves (except one). The results do not support the concept of risk homeostasis, although there is evidence of risk compensation.
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Deller, Jason. "The effects of road geometry and posted speed limits on driver speed selection." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/205849/2/Jason_Deller_Thesis.pdf.
Full textAbstract:
This research investigates the complex relationship between roadway design and operating speeds and how drivers respond to these roadway design characteristics. It seeks to understand the effects of road geometry within a complex urban road environment on driver speed selection by conducting an advanced driving simulator experiment and an observational study completed in an Australian town. The results show that a reduction or an increase in lane width, the presence of posted speed signage or a change in the posted speed limit, horizontal curves, and centre line marking influence driver speed selections along low-speed urban corridors.
15
Stránský, Jakub. "Optimalizace vybraných návrhových prvků ČSN pro projektování pozemních komunikací." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227496.
Full textAbstract:
The master‘s thesis focuses on the optimization of the design values of curves of the horizontal alignments of the roads. It deals with the comparison of values between czech and foreign standards and differences between them. The practical part examines the values of the real speeds of vehicles passing through the curves of various parameters that were measured during measurements of selected curves during 2014. From these data a new design values are derived that could be used for the design of horizontal alignments.
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Ibrahim, Shewkar El-Bassiouni. "Risk-based design of horizontal curves with restricted sight distance." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/32687.
Full textAbstract:
Current geometric design guides provide deterministic standards where the safety margin of the design output is generally unknown and there is little knowledge on the safety implications of deviating from these standards. Several studies have advocated probabilistic geometric design where reliability analysis can be used to account for the uncertainty in the design parameters and to provide a risk measure of the degree of deviation from design standards. In reliability analysis, this risk is represented by the probability of non-compliance (Pnc) defined as the probability that the supply exceeds the demand. However, there is currently no link between measures of design reliability and the quantification of safety using collision frequency. The analysis presented in this thesis attempts to incorporate a reliability-based quantitative risk measure in the development of Safety Performance Functions (SPFs).
The thesis considers the design of horizontal curves, where non-compliance occurs whenever the available sight distance (ASD; supply) falls short of the stopping sight distance (SSD; demand). The inputs of SSD are random variables and appropriate probability distributions were assumed for each. A comprehensive database for the Trans-Canada Highway was used to compute the probability of non-compliance (Pnc) for 100 segments of horizontal curves. Several Negative Binomial (NB) Safety Performance Functions (SPFs) were developed and the predicted collisions were found to increase with risk (Pnc) and that the rate of increase varies by severity level. The likelihood ratio test showed that the inclusion of a risk parameter (Pnc) has generated better predictive models that have significantly outperformed the traditional models. Further, a spatial analysis was carried out which showed that the spatial models were successful in overcoming potential model misspecification resulting from incorporating only exposure and Pnc in the SPFs as relevant covariates might have been omitted.
The optimization of cross-section design to minimize the risk associated with restricted sight distance was also considered using a multiple objective function that involves new Collision Modification Factors (CMFs) incorporating Pnc. The results indicated that accounting for the random variations due to drivers’ behavior proactively at the design stage would decrease collisions in addition to achieving an overall risk reduction.
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Libichová, Jana. "Studie MÚK silnic R43 s I/43." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225918.
Full textAbstract:
Aim of this Master´s thesis is the road adjustment and design of new grade separated junction highway R43 and road I/43,of Černá Hora – Svitávka and to design optimal distribution of transport hubs including the design II/150 and III/37429, which should be connected with existing roads.The adjustment of the routes will be designed in the necessary extent with the optimal distribution of transport hubs regarding the best transport and economical solution and with minimal impact on the enviroment.
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Kozák, Petr. "Napojení JV obchvatu města Jihlavy-křižovatka silnic I/38 a II/523." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225923.
Full textAbstract:
This diploma work deals with researching study of transport junction of main road I/38 and major road II/523 and than link-up of the proposed Outer ring road (VMO) and Southeastern by-pass (JVO) routes of region capital Jihlava, district of Jihlava, Vysočina region. Road structure will solve designed staged link-up of aboved mentioned roads according to their construction schedule. The design takes into account current roads and completed stages, with respect to minimum costs. Road structure is situated on Czech-Moravian Highlands. Its terrain is hilly, pondy and composed of agricultural parcels. The main purpose of this design is steady link-up of all considered traffic flows in the given locality.
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Reis, Rodrigo Martins. "Comportamento tensão-deformação de dois horizontes de um solo residual de gnaisse." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-06112006-163715/.
Full textAbstract:
Neste trabalho estuda-se o comportamento tensão-deformação de dois horizontes de um solo residual de gnaisse, pertencentes a um perfil típico da cidade de Viçosa-Minas Gerais, na condição saturada e sob diferentes valores de sucção. O estudo apóia-se em ensaios de caracterização física e mineralógica, em ensaios destinados às análises porosimétricas e morfológicas (lâminas delgadas), e em ensaios de compressão triaxial realizados em corpos de prova não saturados e saturados, estes sujeitos a diferentes direções de cisalhamento, em ambos solos, e distintas trajetórias de tensão, no solo jovem. Nos ensaios triaxiais saturados mostra-se que a resistência dos dois solos foi independente da direção de cisalhamento e que a deformabilidade revelou-se mais anisotrópica no solo maduro, que no solo jovem, este visualmente mais heterogêneo. Mostra-se, que o intercepto de coesão cresce com a sucção numa relação que pode ser bem representada por uma função hiperbólica e que o ângulo de atrito interno praticamente não apresentou variação com a sucção matricial. Apresenta-se uma alternativa de previsão da envoltória de resistência, baseada nos parâmetros de resistência do solo saturado e nos resultados de ensaio correspondente a uma sucção conhecida. A curva de plastificação do solo jovem pôde ser representada razoavelmente bem pela curva adotada nos modelos derivados da mecânica dos solos dos estados críticos (Cam-Clay modificado). A curva é centrada no eixo hidrostático e sua forma não apresenta mudança marcante durante o encruamento do solo, o qual foi obtido através da união de pontos com o mesmo trabalho plástico.This thesis deals with the stress-strain behavior of a mature soil and a young soil from a typical residual soil of gneiss, as found in Viçosa-MG. This behavior is analyzed under saturated and non saturated conditions. The study rests on physical and mineralogical characterization tests, on porosimetric and morphological analyses (thin section) and on triaxial compression tests performed with saturated and non saturated soil. Saturated young and mature specimens were sheared according to different directions and saturated young soil was also sheared following various stress path. It is shown that the shear strength of saturated soil, both mature and young is independent of shearing direction. However, the visually more homogeneous mature soil showed to be more anisotropic, regarding the deformability, than the young residual soil that visually seems to be heterogeneous. The cohesion intercept tends to increase with soil suction according to a non linear relationship that can be adjusted through a hyperbolic function, while the angle of shearing stress was not influenced by soil suction. An alternative to forecast unsaturated shear strength envelope based on results of saturated soil and on tests performed at a known suction is also presented. The yielding curve of young soil was found to be fairly predicted using modified Cam-Clay model. The yield curve is centered along the hydrostatic axis of stress and its shape didnt change during soil strain hardening that was obtained by joining the points to that exhibited the same plastic work.
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Křemen, Tomáš. "Rekonstrukce železniční stanice Milevsko." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227594.
Full textAbstract:
The aim of the diploma thesis is the reconstruction of Milevsko railway station. The platforms with access persons with reduced mobility are designed in this station. The rail substructure and station drainage system design was necessary to do within the reconstruction. New assembly of a switches and crossing is the part of reconstruction design as well.
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Kim, Yoon Duk. "Transverse Stiffener Requirements in Straight and Horizontally Curved Steel I-Girders." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4802.
Full textAbstract:
Recent research studies have confirmed that curved I-girders are capable of developing substantial shear postbuckling resistance due to tension field action and have demonstrated that the AASHTO LRFD equations for the tension field resistance in straight I-girders may be applied to curved I-girders within specific limits. However, the corresponding demands on intermediate transverse stiffeners in curved I-girders are still largely unknown. Furthermore, a number of prior research studies have demonstrated that transverse stiffeners in straight I-girders are loaded predominantly by bending induced by their restraint of web lateral deflections at the shear strength limit state, not by in-plane tension field forces. This is at odds with present Specification approaches for the design of transverse stiffeners, which are based on (1) providing sufficient stiffener bending rigidity only to develop the shear buckling strength of the web and (2) providing sufficient stiffener area to resist the in-plane tension field forces.
In this research, the behavior of one- and two-sided intermediate transverse stiffeners in straight and horizontally curved steel I-girders is investigated by refined full nonlinear finite element analysis. Variations in stiffener rigidity, panel aspect ratio, panel slenderness, and stiffener type are considered. New recommendations for design of transverse stiffeners in straight and curved I-girder bridges are developed by combining the solutions from the above FEA studies with the results from prior research.
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AlHamaidah, A. S. M. "The structural behaviour of horizontally curved prestressed concrete box girder bridges." Thesis, University of Salford, 2017. http://usir.salford.ac.uk/43834/.
Full textAbstract:
Bridges are important and efficient structures which are comprised of a number of elements and substructures, namely the deck, abutment and foundation and possibly additional intermediate supports. Recently the horizontally curved box girder bridge has become more desirable in modern motorway systems and big cities. Even though numerous amounts of research have been in progress to analyse and understand the behaviour of all types of box-girder bridges, the results from these different research projects are unevaluated and dispersed. Therefore, a clear understanding of an accurate study on straight and curved box-girder bridges is needed. In this study, a three dimensional straight and horizontally curved prestressed box section has been analysed with shell elements using the finite element analysis program ANSYS to examine structural behaviour and load carrying capacity. The box girder under static gravity, pre-stressed and gravity + pre-stressed loading has been analysed. The model which has been investigated in this report is taken from a published paper and expanded to study the effects of curvature under different loads applied (UDLs). The report concludes that the FEA using shell elements is able to predict the behaviour of box girders with adequate accuracy through the comparisons made between stress results from analytical hand calculations and published work, both for the straight and curved box girder bridges. Further theoretical and analytical investigations have been carried out to study the effects of parameters such as horizontal curvature, prestressing, and traffic patterning. For this purpose, a new model was created, modelled with an accurate prestress representation and analysed as a three-dimensional model using the ANSYS. This thesis presents a complete description of the bridge system, addressing the aforementioned parameters and presenting the results through graphs of stress distribution, and displacement. Recommendations for the practical use of FE for bridge design are discussed.
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Gong, Huafeng. "Operating speed preditcion [sic] models for horizontal curves on rural four-lane non-freeway highways." Lexington, Ky. : [University of Kentucky Libraries], 2007. http://hdl.handle.net/10225/727.
Full textAbstract:
Thesis (Ph. D.)--University of Kentucky, 2007.Title from document title page (viewed on March 25, 2008). Document formatted into pages; contains: x, 182 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 136-149).
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Clarke, David Langton. "The effect of manipulating movement-illusion-inducing stimuli on reducing traffic speed on horizontal curves." Scholarly Commons, 1990. https://scholarlycommons.pacific.edu/uop_etds/2937.
Full textAbstract:
This study assessed the effectiveness of pavement markings painted along the curbs of a two-lane street on reducing driving speed around a curve. Three different types of marking patterns were investigated in a single-case design. The velocity and perceived speed of vehicles passing through a frequently used entrance road on a university campus were measured. Velocity was measured by recording the time it took vehicles to travel 150 ft (45.7 m). To measure perceived speed, volunteer observers rated the speed of videotaped vehicles using a 15 item questionnaire developed for this study. Data were collected only on passenger vehicles during clear weather conditions. The velocity measure indicated that markings, particularly those in a checkerboard pattern, were effective in reducing the number of drivers exceeding 35 mph. This outcome is consistent with the findings from previous studies with similar interventions. The perceived speed measure did not show meaningful trends across phases. Future research with this type of inexpensive intervention and the need to develop a valid and reliable measure of perceived speed, which takes into consideration safety factors in assessing driving behavior, is discussed.
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Jung, Se-Kwon. "Inelastic Strength Behavior of Horizontally Curved Composite I-Girder Bridge Structural Systems." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11618.
Full textAbstract:
This research investigates the strength behavior of horizontally curved composite I-girder bridge structural systems, and the representation of this behavior by the AASHTO (2004b) LRFD provisions. The primary focus is on the design of a representative curved composite I-girder bridge tested at the FHWA Turner-Fairbank Highway Research Center, interpretation of the results from the testing of this bridge, including correlation with extensive linear and nonlinear finite element analysis solutions, and parametric extension of the test results using finite element models similar to those validated against the physical tests. These studies support the potential liberalization of the AASHTO (2004b) provisions by the use of a plastic moment based resistance, reduced by flange lateral bending effects, for composite I-girders in positive bending.
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Ozgur, Cagri. "Behavior and Analysis of a Horizontally Curved and Skewed I-girder Bridge." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14637.
Full textAbstract:
This thesis investigates the strength behavior of a representative highly skewed and horizontally curved bridge as well as analysis and design procedures for these types of structures. The bridge responses at and above a number of limits in the AASHTO (2007) Specifications are considered. The study includes the evaluation of various attributes of the elastic analysis of the subject bridge. These attributes include: (1) the accuracy of 3-D grid versus 3-D FEA models, (2) first-order versus second-order effects during the construction, (3) the ability to predict layover at bearing lines using simplified equations and (4) the benefit of combining the maximum and concurrent major-axis and flange lateral bending values due to live load compared to combining the maximums due to different live loads when checking the section resistances. The study also addresses the ability of different AASHTO 2007 resistance equations to capture the ultimate strength behavior. This is accomplished by comparing the results from full nonlinear 3-D FEA studies to the elastic design and analysis results. Specifically the use of the 2007 AASHTO moment based one-third rule equations is evaluated for composite sections in positive bending.
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Cullen, Lauren E. "An evaluation of the strength characteristics of horizontally curved steel I-girder bridges." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5033.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains ix, 226 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 179-187).
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Pofahl, Geoffrey Michael. "Essays on horizontal merger simulation: the curse of dimensionality, retail price discrimination, and supply channel stage-games." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4833.
Full textAbstract:
In the words of Joel I. Klein, former Assistant Attorney General of the United
States, âÂÂ[a]ntitrust enforcement in the merger area has never been as time-consuming,
complex, or as central to the functioning of our economy as it is todayâ (Klein, 1998).
As such, the development of transparent, efficient, and accurate merger analysis tools is
an endeavor whose value continues to increase in the eyes of regulators and industry
participants alike. Arguably, the most visible result of such endeavors is the emergence
and advancement of a practice known as merger simulation.
The first goal of this dissertation is to evaluate the merits of the Distance Metric
(DM) demand model and its usefulness in merger simulations. Revered by its creators as
easy-to-use, flexible, and able to handle large numbers of products, the DM approach
has not received the âÂÂroad-testingâ necessary for establishing its practical usefulness.
The DM model is used to estimate demand elasticities for 45 bottled-juice products.
Elasticities are then used to simulate numerous hypothetical mergers. While adding
validity to the alleged strengths of the DM approach, an additional contribution is made
by demonstrating the robustness of merger simulation results across 22 DM
specifications. Despite the oft-recognized reality of zone pricing by food retailers, this form of
price discrimination has received little attention within the context of upstream merger
analysis. Thus, the second objective of this dissertation is to relax the conventional
merger simulation assumption of uniform pricing by retailers, allowing us to explore the
impacts of zone pricing on post-merger price effects. Using the ready-to-eat cereals
industry as a backdrop, it is shown that ignoring retail price discrimination veils a
potentially diverse set of price effects that are otherwise lost in uniform pricing analyses.
The goal of the final essay is to explore the implementation of more realistic
supply channel interactions in merger simulations. In particular, a two-stage pricing
game is used to conduct merger simulations in the refrigerated orange juice category.
The overriding finding is that comparisons with conventionally used models will not be
practical until the relationship between demand specification and two-stage game
modeling is better understood.
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Navarro, Moysés Alberto. "Estudo da limitação do escoamento em contracorrente agua/ar em canais horizontal e inclinado unidos por curva." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267548.
Full textAbstract:
Orientadores: Roger Josef Zemp, Paulo de Carvalho TofaniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: A limitação do escoamento em contracorrente, ou inundação, fenômeno caracterizado pelo controle que um gás exerce no escoamento de um líquido em sentido contrário, desempenha papel importante em diversos equipamentos das engenharias química e mecânica (condensador de refluxo, colunas recheio, tubos de calor etc.). Mais recentemente, o fenômeno tem recebido atenção especial da área nuclear devido à sua influência no comportamento termo fluido dinâmico de um reator nuclear durante um acidente de perda de refrigerante. A maioria dos estudos experimentais e analíticos sobre a inundação foi executada em tubos verticais. Menor atenção por parte dos pesquisadores tem recebido as geometrias mais complexas como as constituídas por canais de escoamento anulares, com placas perfuradas e, especialmente, aqueles constituídos de tubos horizontal e inclinado conectados por uma curva, como a "perna quente" dos reatores nucleares refrigerados a água pressurizada (Pressurized Water Reactor - PWR). Para melhor subsidiar as análises deste fenômeno, foi conduzido no CDTN/CNEN uma série de experimentos em seções de teste em acrílico com a mesma forma geométrica da "perna quente" de um PWR. Nestes experimentos, o escoamento em contracorrente foi estabelecido com injeção de água pela extremidade superior da tubulação inclinada e de ar através da outra extremidade da seção. Com incursão gradual ascendente na velocidade do ar para níveis de injeção de água preestabelecidos, foram determinadas as velocidades de início de arraste da água pelo ar, de início de arraste total e, durante a redução gradativa da velocidade do ar, as velocidades dos fluidos relativas à fase de inundação, quando a penetração da água é controlada pelo escoamento do ar. Com o objetivo de se avaliar as influências das características geométricas do canal de escoamento, foram realizados experimentos com diferentes comprimentos horizontais e inclinados, inclinações do duto inclinado, alturas hidrostáticas acima da extremidade superior e diâmetros da seção de testes. Os resultados experimentais mostraram uma dependência do inicio do arraste com a taxa de injeção água e com as características geométricas da seção de testes. Para uma geometria defmida, na condição de inundação, os pontos experimentais seguem uma curva característica até o início do arraste total assim como, na redução da vazão de ar, até o retomo à precipitação total, que independente da taxa de água injetada. Variações (:t 20°) em tomo de 50° na inclinação pouco afetam o comportamento da curva de inundação. Foi constatado ainda que, para uma mesma velocidade de ar, o aumento do comprimento horizontal ou do inclinado da seção provoca o aumento do arraste de água. O levantamento das influências dos parâmetros geométricos da seção de testes no comportamento da inundação gerou uma nova correlação para o fenômeno
Abstract: The Countercurrent Flow Limitation (CCFL), or flooding, is characterized by the restraint imposed by a gas on a countercurrent liquid flow. The phenomenon plays important role in several equipment in the chemical and mechanical engineerings (reflux condensator, packed columns, heat pipes). More recently the phenomenon has received special attention by the nuclear area due to its influence in the thermal-hydraulic behavior of a nuclear reactor during a postulated loss of coolant accident. Most of the experimental and analytical studies about the flooding was performed in vertical ducts. The more complex geometries, such as annular channels, or channels with perforated plates and, especially, those which are constituted by a horizontal pipe connected to an inclined riser, as the hot leg of the Pressurized Water Reactors - PWR, have received little attention by the researchers. To subsidize the analyses of this phenomenon, experiments in test sections with the same geometric form of the hot leg of a PWR were carried in CDTN/CNEN. In these experiments, the countercurrent flow was established with water injection in the upper extremity of the inclined pipe associated to air injection through the other extremity of the test section. With ascending and gradual air flow rate, for specific water flow rates, the air velocities at the onset of flooding and at the onset of total water carryover were measured. During an air flow rate reduction phase, the relative fluids velocities in the flooding phase, when the water penetration is controlled by the air in countercurrent, were also determined. In order to evaluate the influence of the geometric characteristics of the test section, experiments with different horizontal and inclined lengths, inclinations of the inclined riser, water head above the upper extremity and diameters of the test section, were also performed. The experimental results showed that the onset of flooding is a complex function of water flow late injection and depends on the geometry of the test section. For a specific geometry, in the flooding condition, the experimental points follow a characteristic curve ITom the onset of the total carryover until the total water precipitation. These flooding curve was found to be independent of the injected water flow rate. The imposed variations (:t 20) around 50° in inclination of the inclined riser produced negligible effects in the flooding curve. It was also verified that, for a same air velocity, a longer horizontal or inclined length induces an increase in the carryover water. This study proposes a new flooding correlation considering the influence of the geometrical parameters
Doutorado
Sistemas de Processos Quimicos e Informatica
Doutor em Engenharia Química
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Raif, Lukáš. "Studie rekonstrukce železniční stanice Prostějov hl.n." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226633.
Full textAbstract:
The aim of the diploma thesis is the reconstruction of Prostějov hl. n. railway station. The platforms with access persons with reduced mobility are designed in this station. The rail substructure and station drainage system design was necessary to do within the reconstruction. New assembly of a switches and crossing is the part of reconstruction design as well.
31
Hartmann, Joseph Lawrence. "An experimental investigation of the flexural resistance of horizontally curved steel I-girder systems." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2378.
Full textAbstract:
Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Civil Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Linzell, Daniel Gattner. "Studies of a full-scale horizontally curved steel I-girder bridge system under self-weight." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/18342.
Full text
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Khamlaj, Tariq A. "Analysis and Optimization of Shrouded Horizontal Axis Wind Turbines." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1543845571758119.
Full text
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Knecht, Casey Scott. "Crash Prediction Modeling for Curved Segments of Rural Two-Lane Two-Way Highways in Utah." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4352.
Full textAbstract:
This thesis contains the results of the development of crash prediction models for curved segments of rural two-lane two-way highways in the state of Utah. The modeling effort included the calibration of the predictive model found in the Highway Safety Manual (HSM) as well as the development of Utah-specific models developed using negative binomial regression. The data for these models came from randomly sampled curved segments in Utah, with crash data coming from years 2008-2012. The total number of randomly sampled curved segments was 1,495. The HSM predictive model for rural two-lane two-way highways consists of a safety performance function (SPF), crash modification factors (CMFs), and a jurisdiction-specific calibration factor. For this research, two sample periods were used: a three-year period from 2010 to 2012 and a five-year period from 2008 to 2012. The calibration factor for the HSM predictive model was determined to be 1.50 for the three-year period and 1.60 for the five-year period. These factors are to be used in conjunction with the HSM SPF and all applicable CMFs. A negative binomial model was used to develop Utah-specific crash prediction models based on both the three-year and five-year sample periods. A backward stepwise regression technique was used to isolate the variables that would significantly affect highway safety. The independent variables used for negative binomial regression included the same set of variables used in the HSM predictive model along with other variables such as speed limit and truck traffic that were considered to have a significant effect on potential crash occurrence. The significant variables at the 95 percent confidence level were found to be average annual daily traffic, segment length, total truck percentage, and curve radius. The main benefit of the Utah-specific crash prediction models is that they provide a reasonable level of accuracy for crash prediction yet only require four variables, thus requiring much less effort in data collection compared to using the HSM predictive model.
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Tapia, Tadeo Abdon. "Modelagem dos acoplamentos mecanicos nos sistemas horizontais rotor-acoplamento-mancal." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264190.
Full textAbstract:
Orientador: Katia Lucchesi Cavalca DediniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Doutorado
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Chavez, Quispe Juan Carlos. "Kalla kallan, un centro de interacción Yunga-Kallawaya - Tiwanaku en los valles de Charazani - Curva durante el horizonte medio (ca. 500-1150 D.C.)." Universidad Mayor de San Andrés. Programa Cybertesis BOLIVIA, 2010. http://www.cybertesis.umsa.bo:8080/umsa/2010/chavez_qj/html/index-frames.html.
Full textAbstract:
El Horizonte Medio ha visto el origen y caída de dos entidades macroregionales del mundo andino (Tiwanaku y Wari). Sin embargo, en este periodo también se han desarrollado una serie de organizaciones socioculturales locales de importancia regional como es el caso de los grupos Yunga-kallawaya en los valles de Charazani - Curva. Si bien el territorio montañoso de esta región ha sufrido la implantación de complejos agrícolas durante el Horizonte Tardío, su carácter económico productivo deviene del Horizonte Medio. En ambos casos el acceso a la producción de maíz es uno de los factores que han motivado los procesos de incursión y ocupación de grupos altiplánicos en estos valles mesotermos septentrionales. En tal contexto surge Kalla kallan como un centro de interacción enclavado entre los valles de Charazani – Curva, y posicionado sobre la ruta más directa hacia las tierras bajas orientales. El origen de este asentamiento data de la fase final del Formativo regional e inicios del Horizonte Medio, y su colapso parece coincidir con la fase final del Horizonte Medio de los Andes Centro Sur. El rango de actividades desplegadas en Kalla kallan ha sido consolidado en torno a su funcionalidad como asentamiento dentro de la organización regional de la entidad local aquí denominada Yunga-kallawaya. Esta dinámica supuso la transformación de Kalla kallan de un centro de confluencia económica a un centro regional de interacción ideológica, religiosa y festiva asociada a Tiwanaku.
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Vančura, Lukáš. "Most na rampě v Brně." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226930.
Full textAbstract:
The topic of the thesis is the design and assessment of roadway bridge structure, which is curved in the horizontal plan with a very small radius. Bridges is part of the flyover crossing in Brno. There are designed two variations of which are further developed the variant of the two-chamber cross-section. Calculations and assessments are conducted in according to the valid European standards (Eurocodes). The static calculation is supplemented with a clear technical drawings and visualizations.
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Novotný, Jan. "Most na rampě křižovatky v Brně." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226435.
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Thesis deals with horizontally curved bridge on the ramp in Brno. Designed structure is continous beam formed by bicameral shape, on which are considered the effects of traffic according to ČSN EN 1991-2. Based on the results of stress the structure is designed.
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Lašinytė, Asta. "Žemės paėmimo visuomenės poreikiams įtakos žvyrkelių rekonstrukcijos kainai VĮ „Telšių regiono keliai“ veiklos zonoje vertinimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050613_101359-36656.
Full textAbstract:
The final master‘s work analyzes problems which occur or may occur due to taking the land for public needs when implementing the program of asphalt works on gravel roads in the area of activity of state enterprise „Telšių regiono keliai“. A research of sections of gravel roads intended for reconstruction and included into the program of maintenance and expansion of public highways for 2002–2015 was carried out, in the course of which a road plan was projected following norms of road engineering and the extent of taking the land for public needs was evaluated. Recommendations regarding the expedience of taking the land for road lane when implementing the program of asphalt works on gravel roads in the area of activity of state enterprise „Telšių regiono keliai“ were rendered.
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Lin, Yu-ting, and 林郁庭. "centrifuge modeling on the p-y curve of mono-pile foundation for offshore wind turbines under cyclic horizontal loadings." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/72065716894031684246.
Full textAbstract:
碩士國立中央大學
土木工程學系
101
Due to that Taiwan possesses the long and narrow terrain and has very high density of population, offshore wind turbines should be developed along the coast line. Considering that western Taiwan’s long coast line and its comparatively higher wind velocity than that of inland area, it is essential to consider the horizontal ultimate load, horizontal displacement of pile, rotating angle together with the maximum bending moment into the design of pile foundations. In this study, the geotechnical centrifuge facility at NCU is used to conduct a series of centrifuge mode test on the offshore wind turbine mono-pile. The mono-pile subjected to a horizontal force to investigate the corresponding acts of a mono-pile while affected by horizontal pushover. In this research, the pile foundation of Denmark’s offshore wind farm is used as the model in designing pile foundation model. First, 40% of its original size is reduced, and then the reduced model is scaled down in accordance with the scale rule, which is later on been put in centrifugal field of 80g for testing in which the researcher applies pressure regulating valve to control air pressures to apply the horizontal force to the pile. During the process, the researcher measures the horizontal displacement of pile, the distribution of bending moment along depths with its corresponding horizontal force and applies regression analysis to get the changes of shearing force of pile(V), coefficient of soil reaction(p), rotating angle of pile(θ) and last, of displacement of pile. The test results reveals that the pile embedded in the saturated sand bed will cause more displacement than that in the dry sand bed under the same magnitude of horizontal force. And, the further the pushover applies to the pile, the greater the bending moment on the pile. As a result, the pile suffers the greater bending moment and the greater pile horizontal displacement. The testing outcome of the p/D-y curves on the pile measured from both the dry sand bed and the saturated sand bed we can conclude that increase in the depths would increase the soil reactions at the same horizontal displacement of pile head.
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VALLURU, KRISHNA. "Impact of Perceptual Speed Calming Curve Countermeasures On Drivers’ Anticipation & Mitigation Ability – A Driving Simulator Study." 2018. https://scholarworks.umass.edu/masters_theses_2/706.
Full textAbstract:
A potential factor for curve accidents are anticipatory skills. Horizontal curves have been recognized as a significant safety issue for many years. This study investigates the impact and effectiveness of three curve based perceptual speed calming countermeasures (advanced curve warning signs, chevron sign, and heads-up display(HUD) sign) on drivers’ hazard anticipation and mitigation behavior across both left and right-winding curves, and sharp (radius 200m) and flat (radius 500m) curves. Experimental results show that the speed and lateral control in the horizontal curves differed with respect to curve radii, direction, and the type of countermeasure presented. These differences in behavior are probably due to curve-related disparities, the type of perceptual countermeasure, and the presence of hazard at the apex of the curve. HUD is found to be effective at not only reducing the drivers’ speed in the curve, but also improve the latent hazard anticipation ability of the driver at the apex of the curve. Flat and sharp curves with indications of a safety problem were virtually developed in the simulator as representative as possible without upsetting the simulator’s fidelity. 48 participants were recruited for this study between the age range of 18 and 34, and driving experience range was from 0.25 to 17.75 years.
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Felipe, Emmanuel Leon. "Reliability-based design for highway horizontal curves." Thesis, 1996. http://hdl.handle.net/2429/4497.
Full textAbstract:
For more than fifty years the notion of comfortable lateral acceleration has governed the
horizontal curve design procedure in North America. With new road and vehicle technology,
new methods of design have to replace the old procedures to provide consistent and safer roads
to the users. The "limit state design" concept, taken from structural engineering, has already
shown to provide a meaningful value of safety to highway design, see Navin (1990-1992).
With the cooperation of the British Columbia Ministry of Transportation and Highways,
controlled experiment and field observation were performed to develop the "limit state design"
concept for highway horizontal curves. These measurements allowed to accumulate actual
statistical information of the basic variables involved in the driving process of horizontal curves.
During the experiment, designed with a Latin Square, eight regular drivers and two expert drivers
drove four different curves at two speed levels and two pavement conditions. The response
variables from this experiment were the lateral acceleration, the speed and the level of comfort.
During the observation, in addition to the geometric characteristics of the four horizontal curves
selected on the "Sea to Sky" Highway, the speed, lateral acceleration and lateral placement of the
free moving passenger cars traveling through these curves were gathered.
The computer program RELAN was used to perform First Order Reliability Method (FORM)
analysis for passenger cars subjected to skidding by comparing the expected lateral acceleration supplied by the road to the expected lateral acceleration demanded by the vehicle-driver.
RELAN was also used to compute the reliability index P and to provide the probability of noncompliance
for existing highway horizontal curves, by comparing the expected radius supplied
by the highway to the expected radius demanded by the car/driver system. From data collected
during the empirical studies^ results show an increased probability of non-compliance with a
decrease of radius.
Using reliability-based design method, transportation engineers can adjust the design of
horizontal curves to fulfill a desirable probability of non-compliance or a desirable reliability
index (3. Designers have also a representation of the main variables involved in the process of
driving in a horizontal curve and, therefore, have a better control of their designs. With
reliability analysis, transportation engineering is provided with a highway design method which
better responds to the actual driving demand on the road, and is supported with a measure of 'safety' or non-compliance.
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Shih-Ho, Jaw, and 趙世鶴. "DYNAMIC ANALYSIS OF MULTISPAN HORIZONTALLY CIRCULAR CURVED BEAMS." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/84545867346540851768.
Full textAbstract:
碩士國立中興大學
土木工程研究所
83
The thesis is devoted to the dynamic analysis of horizontally circular curved beams. The direct stiffness method is used to derived the dynamic stiffness matrix for finding the natural frequ- encies and joint moments of curved beams having different rectangular cross-sections. Several examples are presented to illustrate the appli- cation of the proposed method and to show the effects of rotatory inertia, shear deformation, torsional inertia, warping and opening angle of the arc on the beam. The first examples are for the free vibration of the beam. In these exampl- es, beams with different thickness are used for finding effects of warping. In each example, there are three cases; case(a) consider rotatory inertia, shear deformation, torsional inertia and warping effects; case(b) consider rotatory inertia, shear deformation and torsional inertia effects; case( c) consider rotatory inertia, shear deformation and warping effects. The last example is for the forced vibration of the beam subjected to a uniformly distributed load. The results of the last examples show the effects of case(a),(b) and (c) on the joint moment of the beam. We also let the forced frequency to be zero for finding the static special moment.
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Quaium, Ridwan B. "A Comparison of Vehicle Speed at Day and Night Rural Horizontal Curves." 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-8024.
Full textAbstract:
This thesis documents the linear mixed model developed for vehicle speed along two-lane two-way rural horizontal curves in the outside lane. Speed data at each curve was collected at four points along the curve including the midpoint of the curve for a minimum of 48 hours during weekdays. Vehicle speed was analyzed separately for day and night conditions. The horizontal curves were categorized into different groups using different methods using side friction demand, radius and pavement edgeline marking retroreflectivity.
In the speed prediction model, radius, superelevation at the midpoint of the curve, deflection angle, posted speed limit and pavement edgeline marking retroreflectivity were used to predict the vehicle speed at the midpoint of the horizontal curve. The regression analysis indicates that all of these variables are statistically significant in predicting the vehicle speed at the midpoint of horizontal curves with a 95 percent confidence interval. The linear model determined that the vehicle speed has a positive relation with the radius of the curve, superelevation and posted speed limit but has a negative relation with the deflection angle and pavement edgeline marking retroreflectivity.
Curves were categorized based on side friction demand or radius and retroreflectivity of pavement edgeline marking. ANOVA was used to compare the day and night time speed. The comparisons reveal that vehicle speed at the horizontal curves decreases as the side friction demand value of the curves increases. Another finding of this research was that even though the posted speed limit is incorporated into the calculation of side friction demand, it may be necessary to analyze the impact of posted speed limit on vehicle speed for both daytime and nighttime. Previous literature determined that drivers may drive at an unsafe speed during nighttime at high levels of retroreflectivity. The results of this study could not confirm this statement as data from this study suggests that for curves with pavement edgeline marking retroreflectivity greater than 90 mcd/m2/lx, the effects of retroreflectivity on speed was determined to be minimal. This is based on the finding that the daytime and nighttime speeda were basically the same as the daytime and nighttime speed difference was both statistically and practically insignificant.
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Chang, Sung-Fa, and 張松發. "Numerical Study for Laminar Flow and Heat Transfer in Horizontal Curved pipe." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/97501267915174273269.
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Kim, Dongjoo. "Evaluation of displacements and stresses in horizontally curved beams /." Diss., 2005. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3203819.
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Fan, Zhuo. "Behavior of horizontally curved steel tubular-flange bridge girders." 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3270655.
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Dong, Jun. "Analytical study of horizontally curved hollow tubular flange girders." 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3344782.
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Stith, Jason Clarence. "Predicting the behavior of horizontally curved I-girders during construction." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-08-1840.
Full textAbstract:
The majority of a bridge designer’s time is spent ensuring strength and serviceability limit states are satisfied for the completed structure under various dead and live loads. Anecdotally, the profession has done an admirable job designing safe bridges, but engineering the construction process by which bridges get built plays a lesser role in the design offices. The result of this oversight is the complete collapse of a few large bridges as well as numerous other serviceability failures during construction. According to the available literature there have been only a few attempts to monitor a full-scale bridge in the field during the entire construction process. Another challenge for engineers is the lack of analysis tools available which predict the behavior of the bridge during the intermediate construction phases. During construction, partial bracing is present and the boundary conditions can vary significantly from the final bridge configuration. The challenge is magnified for complex bridge geometries such as curved bridges or bridges with skewed supports.
To address some of the concerns facing engineers a three span curved steel I-girder bridge was monitored throughout the entire construction process. Field studies collected data on the girder lifting behavior, partially constructed behavior, and concrete deck placement behavior. Additional analytical studies followed using the field measurements to verify the finite element models. Finally, conclusions drawn from the physical and analytical testing were utilized to derive equations that predicted behavior, and analysis tools were developed to provide engineers with solutions to a wide range of construction related problems. This dissertation describes the development of two design tools, UT Lift and UT Bridge. UT Lift is a macro-enabled Excel spreadsheet that predicts the behavior of curved I-girders during lifting. The derivation of the equations necessary to accomplish these calculations and the implementation are described in this dissertation. UT Bridge is a PC-based, user-friendly, 3-D finite element program for I-girder bridges. The basic design philosophy of UT Bridge aims to allow an engineer to take the information readily available in a set of bridge drawings and easily input the necessary information into the program. A straight or curved I-girder bridge with any number of girders or spans can then be analyzed with a robust finite element analysis for either the erection sequence or the concrete deck placement. The development of UT Bridge as well as the necessary element formulations is provided in this dissertation.text
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Wu, Der Cheng, and 吳得政. "Distortional Analysis of Horizontally Curved Composite Steel Box Girder Bridges." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/53350814432924733491.
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