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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Análise sísmica de estruturas enterradas do tipo "Box-Culvert"

Santos, Pedro Jorge January 2012 (has links)
Tese de mestrado integrado. Engenharia Civil. Faculdade de Engenharia. Universidade do Porto. 2012
32

Investigation of unsteady and non-uniform flow and sediment transport characteristics at culvert sites

Ho, Hao-Che 01 December 2010 (has links)
The present study is an integral part of a broader study focused on the design and implementation of self-cleaning culverts, i.e., configurations that prevent the formation of sediment deposits after culvert construction or cleaning. Sediment deposition at culverts is influenced by many factors, including the size and characteristics of material of which the channel is composed, the hydraulic characteristics generated under different hydrologic events, the culvert geometry design, channel transition design, and the vegetation around the channel. The multitude of combinations produced by this set of variables makes the investigation of practical situations challenging. In addition to the above considerations, the field observations, and the laboratory and numerical experiments have revealed additional complexities of the flow and sediment transport through culverts that further increase the dimensions of the investigation. The flow complexities investigated in this study entail: flow non-uniformity in the areas of transition to and from the culvert, flow unsteadiness due to the flood wave propagation, and the complex correlation between the flow and sediment hydrographs produced during storm events. To date, the literature contains no systematic studies on sediment transport through multi-box culverts. Similarly, there is limited knowledge about the non-uniform, unsteady sediment transport in channels of variable geometry. Furthermore, there are few readily useable numerical models that can reliably simulate flow and sediment transport in such complex situations. Given the current state of knowledge, the main goal of the present study is to investigate the above flow complexities in order to provide the needed insights for optimizing the culvert design. The research was phased so that field observations were conducted first to understand the culvert behavior in Iowa landscape. Modeling through complementary hydraulic model and numerical experiments was subsequently carried out to gain the practical knowledge for the development of the self-cleaning culvert designs.
33

Mule Deer and Wildlife Crossings in Utah, USA

Schwender, Megan 01 May 2013 (has links)
Wildlife-vehicle collisions (WVCs) negatively impact wildlife populations and create dangerous driving situations for motorists. In Utah, USA, mule deer (Odocoileus hemionus) encounter a variety of hazards as they attempt to cross highways and interstates, some of which are 8 lanes wide. Agencies have sought to mitigate the risks posed to drivers and mule deer by building crossing structures for wildlife. The objectives of this study were to evaluate the effectiveness of crossing structures in Utah to safely pass mule deer under highways and to determine the variables that best explain mule deer passage use. From 2008 - 2011 we used 26 camera traps to measure levels of mule deer use of 9 culverts and 4 bridges in Utah. We tested for relationships between mule deer structure use and a variety of structural and landscape attributes at each site, including 2 time variables: time since the structure was built and time each structure was monitored by our camera traps. We also developed and tested a new equation (window ratio) that measured culvert openness to approaching mule deer. In the single variable regression models, mule deer structure use was positively correlated with short culverts and coarse scale shrub cover, and negatively correlated with fine scale grass cover. In the multivariate model, structure use was positively correlated with days monitored and elevation and short culverts. Although the new window ratio did not emerge as the most important predictor for mule deer crossing use, it was more effective at predicting mule deer culvert use than the often referenced openness factor. Our results indicated that 12 of the 13 crossing structures studied effectively facilitate the movement of mule deer in Utah; however some were used far more than others. We suggest that older crossing structures built with the shortest dimensions possible, with attached wildlife-exclusion fencing, and in shrubby habitat will be most effective at passing a high volume of mule deer under Utah highways.
34

Stability Analyses Of The Dump Site Culvert In Tinaz Surface Mine

Ozcan, Omer Can 01 September 2003 (has links) (PDF)
In this thesis, studies associated with the stability analyses of the box-shaped dump-site culvert constructed in Tinaz Surface Mine of Turkish Coal Enterprises (TKi) are presented. In addition, stability conditions of other culvert alternatives are evaluated. Existence of creeks in a surface mining area is a significant factor to be considered in selection of dump-site location. Since, the dumped overburden material on the valley acts as a barrier and behaves like a dam causing flood problem behind the dump-site. TKi engineers prevented the flood potential that might have occurred behind the dump-site by constructing a 480-meter long reinforced-concrete culvert on the downstream of Gevenez Creek Valley. However, considerable amount of deformations occurred in the first 100 meters of the culvert, as a result of overburden material being replaced on this structure. In order to determine the failure mechanism associated with the culvert, a series of numerical modeling analyses were carried out utilizing back analysis technique. The validity of the numerical model was justified by convergence measurements and observations carried out inside the culvert as overburden material being replaced on the stable part of this structure. Finally, based on the numerical model developed, the stability of other culvert alternatives that could be used in future projects were evaluated considering different embankment conditions (positive projecting and negative projecting), bedding conditions (impermissible, ordinary, first-class and concrete cradle), culvert shapes (box and circular) and dumping conditions.
35

Hydraulic Characteristics of Fully Developed Flow in Circular Culverts

Kehler, Nicholas Jon 14 September 2009 (has links)
Throughout the world, particularly in countries such as Canada, water crossings are a significant part of the infrastructure system. Since corrugated metal pipe culverts are an inexpensive choice, as well as hydraulically efficient, they are a very appealing option to designers. To ensure that the natural ecosystem is not adversely affected, culverts must be designed so that throughout the year fish can migrate upstream. Current design regulations are based on the average velocity within the culvert and the prolonged swimming speed of the fish species present. In order to examine the validity of this approach, a physical modeling study was undertaken using a circular CMP culvert. It was found that there is significant cross sectional area below average velocity, and that gravel embedment further increases this area. In addition, a technique was developed that produced very agreeable streamwise velocity predictions over a two dimensional cross section in the developed region.
36

Hydraulic Characteristics of Fully Developed Flow in Circular Culverts

Kehler, Nicholas Jon 14 September 2009 (has links)
Throughout the world, particularly in countries such as Canada, water crossings are a significant part of the infrastructure system. Since corrugated metal pipe culverts are an inexpensive choice, as well as hydraulically efficient, they are a very appealing option to designers. To ensure that the natural ecosystem is not adversely affected, culverts must be designed so that throughout the year fish can migrate upstream. Current design regulations are based on the average velocity within the culvert and the prolonged swimming speed of the fish species present. In order to examine the validity of this approach, a physical modeling study was undertaken using a circular CMP culvert. It was found that there is significant cross sectional area below average velocity, and that gravel embedment further increases this area. In addition, a technique was developed that produced very agreeable streamwise velocity predictions over a two dimensional cross section in the developed region.
37

Parâmetros reprodutivos e condição corporal de três espécies do gênero Astyanax em riachos interceptados por diferentes formas de tubulações / Reproductive parameters and body condition of three species of Astyanax (Ostheichthyes, Characidae) in streams intercepted by culverts

Celestino, Elaine Fernandes 19 August 2011 (has links)
Made available in DSpace on 2017-07-10T18:13:14Z (GMT). No. of bitstreams: 1 Elaine Fernandes Celestino.pdf: 955657 bytes, checksum: 7c921271dc48399794b36854a7c8ca6d (MD5) Previous issue date: 2011-08-19 / Fundação Parque Tecnológico Itaipu / The increase in road construction associated with urbanization can result in habitat fragmentation and loss of fish populations in streams. In this study, we document aspects of reproductive biology and the degree of animal welfare in three species of the genus Astyanax, through analysis of the upstream and downstream sections (above and below) in two distinct forms of culvert (square and circular) in two streams second order tributaries of the Paraná River. For attributes such as reproductive gonadosomatic ratio, diameter of oocytes and fertility did not differ between the sections of the culvert studied. However, the standard length, sex ratio, gonad maturation stages and the condition factor showed significant differences for the species. Be deduced that the species A. altiparanae presents best adapted to the harsh conditions of the culvert and can possibly accomplish movements upstream and downstream of the different types of culvert. While for A. paranae and A. fasciatus results suggest that these species are affected by the culvert e may restrict or hinder movement. / O aumento da construção de estradas associada com a urbanização pode resultar em fragmentação de habitat e perda de populações de peixes em riachos. Neste estudo, documentamos aspectos da biologia reprodutiva e o grau de bem estar animal de três espécies do gênero Astyanax, através da análise dos trechos de montante e jusante (acima e abaixo) de duas formas distintas de tubulação (quadrada e circular), em dois riachos de segunda ordem afluentes do Rio Paraná. Para os atributos reprodutivos tais como Relação gonadossomatica, diâmetro médio do ovócito e fecundidade não apresentaram diferenças entre os trechos das tubulações estudadas. No entanto o comprimento padrão, proporção sexual, estádios de maturação gonadal e o fator de condição apresentaram diferenças significativas para as espécies entre os trechos das tubulações. Podendo inferir que a espécie A. altiparanae apresenta-se melhor adaptada as condições adversas da tubulação, podendo possivelmente realizar os movimentos de montante e jusante das diferentes formas de tubulação. Enquanto que para A. paranae e A. fasciatus os resultados obtidos sugerem que estas espécies são afetadas pela tubulação podendo restringir ou prejudicar sua movimentação.
38

Prototype hydroinformatics-based system for supporting decision making in culvert design and monitoring

Xu, Haowen 01 July 2015 (has links)
The current guideline for culverts design account for hydrologic, hydraulic, and geomorphological conditions at the construction site. Less attention is given to the assessment of the potential for sedimentation within and in the culvert vicinity. Sedimentation becomes an increasing concern for regions where the soil erodibility is historically high (such as the US Midwest) as the recent changes in the land use and climate exacerbate the problem. Culvert design is based on a wide variety of data sources typically stored in various formats in multiple data provider repositories. Assembly of the data needed for design as currently conducted is time consuming and inefficient while the wealth of information garnered through post-construction monitoring is not used to inform the construction of new culverts in the same geographical area. This thesis presents a solution to the issues above using Hydroinformatics approaches. The end product of the thesis is a geo-platform designed to achieve automated culvert design, sediment mitigation design, and digital culvert inspection. The platform has two primary workflows: culvert design and culvert monitoring. All the functions and tools inside the platform are developed using information and GIS technologies. The platform is web assessable, light weighted, and user friendly.
39

Ochrana obce Račice před extravilánovou vodou / The protection of the village Račice against the extravilan run off

Hyžák, Aleš January 2014 (has links)
This thesis deals with problematic of external area water in river basins and its negative impact on the urban areas. The work is divided into two parts. The first part is describes the possibilities of technical interventions in river basins, which can affect the hydrologic conditions in those basins. First part also describes the possibilities of transformation by particular types of draining facilities. Second part of the thesis consists of an analysis of the situation in the village Račice and proposition of hydrotechnological solution for this village.
40

Nvrh vodohospodskch opaten­ v mal©m povod­ / The design of the measures for flood protection in the small watershed

HrnÄ­, Rudolf January 2015 (has links)
My diploma thesis is focused on project of water management measure which should intercept torrential water endangering municipality Starovice. In diploma thesis I assess the degree of erosion washes of soil on the solving land. Intensity of soil ablation of affected land is evaluated by Wischmeier-Smith method. Based on the result of long-term soil lost and gathered materials are designed erosion control and water management measures. Graphic part of the thesis contains cartograms with an assessment rate of erosion threat to the investigated area. As part of thesis maps were created using ArcGIS. The essence of the work are drawings situations, longitudinal profiles, sample diagonal incisions of the intercepting ditch were created in Bentley PowerCivil.

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