As coberturas verdes fazem parte da arquitetura vernacular há séculos como solução para regulação térmica das edificações, retardando a transferência de calor para o ambiente interno e, no inverno, retardando as perdas de calor dos ambientes internos para o exterior da edificação (International Green Roof Association - IGRA). Em se adotando cobertura verde em edificações supõe-se haver economia no consumo de energia para se obter condições de conforto térmico nos ambientes. Baseado nessa suposição foi realizada uma pesquisa experimental onde, por meio de um estudo comparativo entre dois tipos de cobertura: a verde e a de telhas cerâmicas comprovou-se o potencial de economia de energia. A análise do comportamento térmico das coberturas verdes foi realizada por meio de coleta de dados de variáveis ambientais, durante um período de 10 meses, de um protótipo instrumentado, construído no Departamento de Engenharia de Construção Civil da Escola Politécnica da USP, São Paulo. Os dados levantados foram comparados com os dados de um segundo protótipo de mesmas dimensões e igualmente instrumentado, com cobertura cerâmica, sob as mesmas condições ambientais. A comparação dos resultados e análises em dias e episódios representativos de cada estação comprovaram a eficiência das coberturas verdes para retardar o ganho térmico da edificação. Espera-se que os resultados sejam incentivadores à larga aplicação dos telhados egetados, o que trará diversas vantagens para população. / Green roofing is been a part of the vernacular architecture for centuries as solution for constructions thermal regulation. It is known that they delay the heat transfer from the outside to the inside of the building, and during winter, they delay the heating loss from the inside to the outside of the building (International Green Roof Association - IGRA). By adopting green roofs in buildings, one assumes that there is economy in energy consumption to obtain conditions of thermal comfort in inner environments. Based on this assumption, an experimental research was accomplished where, through a comparative study between two types of roofing systems: green and ceramics, it was determined this energy saving potential of green roofs. The analysis of the green roofing thermal behavior was realized through data collection of environmental variables, during the period of ten months, from an instrumented prototype constructed at the Polytechnic School of the University of São Paulo, São Paulo. The collected data was compared to those of a second prototype with the same dimensions and equally instrumented, with ceramics roofing, under the same environmental conditions. The data comparison and analysis of specific days in each season, proved the green roof efficiency on retarding the building thermal gain. One expects that the results will encourage the application of green roofs, which will bring several advantages to the population.

This thesis is a single case study of the introduction and evaluation of new resources and new technologies in higher education; in which e-Proof was chosen as a single case. E-proofs are a multimedia representation of proofs, were created by Alcock (2009), and aimed to help undergraduates to read proofs for better proof comprehension. My thesis aimed to investigate whether the impact of reading such technology-based resource, e-Proofs, on undergraduates proof comprehension was better compared to reading written textbook proofs and if so, then why (or why not). To evaluate the effectiveness of e-Proofs, I used both qualitative and quantitative methods. First I measured undergraduates satisfaction, which is a most common research practice in evaluation studies, by using self-reporting methods such as web-based survey and interviews. A web-based survey and focus-group interviews showed that undergraduates liked to have e-Proofs and they believed that e-Proofs had positive impact on their proof comprehension. However, their positive views on e-Proofs did not evidence the educational impact of e-Proofs. I conducted an interview with Alcock for better understanding of her intentions of creating e-Proof and her expectations from it. Next, I conducted the first experiment which compared the impact of reading an e-Proof with a written textbook proof on undergraduates proof comprehension. Their comprehension was measured with an open-ended comprehension test twice immediately after reading the proof and after two weeks. I found that the immediate impact of reading an e-Proof and a textbook proof were essentially the same, however the long term impact of reading an e-Proof was worse than reading a textbook proof (for both high and low achieving undergraduates). This leads to the second experiment in which I investigated how undergraduates read e-Proofs and textbook proofs. In the second experiment, participants eye-movements were recorded while read- ing proofs, to explore their reading comprehension processes. This eye-tracking experiment showed that undergraduates had a sense of understanding of how to read a proof without any additional help. Rather, additional help allowed them to take a back seat and to devote less cognitive effort than they would otherwise. Moreover, e-Proofs altered undergraduates reading behaviours in a way which can harm learning. In sum, this thesis contributes knowledge into the area of reading and compre- hending proofs at undergraduate level and presents a methodology for evaluation studies of new pedagogical tools.

Thesis (MScEng)--Stellenbosch University, 2003. / Some digitised pages may appear illegible due to the condition of the original hard copy. / ENGLISH ABSTRACT: A critical evaluation of provisions for imposed loads in the South African Loading Code for design of structures, SABS 0160-1989 (SABS), by comparison with other codes was performed earlier. The evaluation revealed the SABS loading code to be generally non-conservative in its provisions for imposed loads for a range of general and specialist occupancy classes. The SABS provision for imposed loads for inaccessible roofs was found to be substantially non-conservative in comparison with the other codes. An investigation into the imposed load for inaccessible roofs is subsequently performed in order to establish a scientific rationale through which the codified design values may be measured effectively. Due to the lack of information and the large uncertainties involved in the imposed roof load, stochastic treatment of the loads is implemented. This is in line with the stochastic modelling of loads as implemented in general. The approach applied is to select a type of building that can be regarded as a generic example of buildings to which these loads apply, and to discretisize the load into the various sub-mechanisms that translate into the imposed roof load. The probabilistic models for the load mechanisms are then quantified, either through physical load surveys, or through conducting an expert survey for those variables which are not observable. The use of expert opinion as a resource for information is not readily accessible in terms of yielding scientifically defendable results. Therefore, the expert survey is performed as a calibrated experiment whereby weights were calculated for the individual experts' opinions and their opinions combined accordingly. The probabilistic models for the load mechanisms are then translated into load effects by taking into account the physical process resulting in the load effects. By applying these mechanisms in such a way as to maximise the said load effects, equivalent uniformly distributed loads (EUDL's) were calculated for each mechanism. The probabilistic models obtained in terms of the EUDL's pose an easily accessible format through which existing load models and codified provisions can be evaluated. These load models are then utilised to evaluate the SABS provisions in terms of the level of reliability catered for by SABS ultimate limit-state design criteria. It is concluded that the SABS conservatively provides for maintenance loads on the roof, while the reliability for construction loads is non-conservative for large tributary areas and highly non-conservative for small areas. The load models so obtained can further be applied for structural reliability assessment. / AFRIKAANSE OPSOMMING: "n Kritiese evaluasie van die voorskrifte vir opgelegde belastings in die Suid- Afrikaanse Selastingskode vir die ontwerp van strukture, SASS 0160-1989 (SASS) deur 'n vergelyking met ander kodes is vroeër uitgevoer. Die evaluasie het getoon dat die SASS in die algemeen onkonserwatief is in sy voorsiening vir opgelegde belastings oor 'n bereik van algemene en spesialis okkupasie tipes. Die SASS voorskrif vir opgelegde belastings vir ontoeganklike dakke is hoogs onkonserwatief in vergelyking met die ander kodes. 'n Ondersoek na die opgelegde belasting vir ontoeganklike dakke word gevolglik uitgevoer met die doelom 'n wetenskaplike rasionaal daar te stel waardeur die gekodifiseerde voorskrifte effektief gemeet kan word. As gevolg van die gebrek aan inligting en groot onsekerhede betrokke by die opgelegde dakbelasting word stogastiese modellering geimplimenteer. Die aanslag wat gevolg is, is om 'n tipe gebou te selekteer wat beskou kan word as verteenwoordigend van die geboue waarvoor hierdie belastings van toepassing is, en om die belasting te diskretiseer in die verskeie lasmeganismes wat die opgelegde dakbelasting voortbring. Die waarskynlikheidsmodelle vir die lasmeganismes word dan gekwantifiseer, óf deur fisiese opnames, óf deur die uitvoering van 'n ekspertopname vir daardie veranderlikes wat nie waarneembaar is nie. Die gebruik van ekspert opinie as "n bron van inligting is nie maklik toeganklik in terme daarvan om wetenskaplik verdedigbare resultate te lewer nie. Daarom is die ekspert-opname uitgevoer soos 'n gekalibreerde eksperiment waardeur relatiewe gewigte bereken word vir die individuele eksperts en hulopinies daarvolgens gekombineer word. Die waarskynlikheidsmodelle vir die lasmeganismes word dan omgeskakel in laseffekte deur in agneming van die fisiese proses wat die las-effek voortbring. Deur die lasmeganismes op só 'n manier toe te pas dat die betrokke las-effekte gemaksimeer word, word ekwivalent uniforme belastings (EUS's) bepaal. Die waarskynlikheidsmodelle in terme van EUS's bied "n maklik toeganklike formaat waardeur bestaande lasmodelle en gekodifiseerde voorskrifte evalueer kan word. Die lasmodelle word gevolglik gebruik om die SASS voorskrifte te evalueer in terme van die vlak van betroubaarheid wat gehandhaaf word deur SASS limiet-staat ontwerp kriteria. Dit is bepaal dat die SASS konserwatief voorsiening maak vir onderhoudslaste op die dak, maar onkonserwatief tot hoogs-onkonserwatief is vir konstruksie laste. Die bepaalde lasmodelle kan verder toegepas word in strukturele betroubaarheids analise.

Coberturas em casca de concreto apresentam bom desempenho estrutural, desde que a forma de sua superfície média seja adequada para resistir predominantemente com esforços de membrana ao carregamento atuante. Atualmente, é possível utilizar-se métodos numéricos para determinar a forma mais adequada de uma casca para carregamentos de naturezas diversas e várias condições de apoio, projetando-se cascas com forma livre. Uma das grandes dificuldades para aplicação dessas estruturas consiste em compatibilizar um processo executivo adequado para moldagem de formas livres, que têm características geométricas muito complexas. A utilização de processo executivo de construção tipo sanduíche, com concreto ou argamassa projetados, é vista neste trabalho como uma alternativa para a viabilização dessas estruturas. Propõe-se definir procedimentos para o projeto de cascas com forma livre, utilizando-se recursos computacionais para definição da forma e análise da estrutura, e um método construtivo adequado a esse tipo de estrutura. Apresentam-se os resultados de geração de formas livres com métodos numéricos disponíveis, bem como parâmetros que podem auxiliar na aplicação dessas formas livres em projetos de coberturas em casca, baseados em resultados numéricos de análise dessas estruturas. São descritas as experiências de execução de dois protótipos de cobertura em casca, com aplicação de argamassa em núcleo de material leve, posicionado entre telas de aço moldadas na forma de membranas pênseis invertidas. Apresentam-se os resultados obtidos em prova de carga de um dos protótipos executados, bem como comparações desses resultados com os obtidos em modelos numéricos, comprovando-se o bom desempenho da estrutura, mesmo sendo a seção formada por duas faces finas sem conexão rígida. Acredita-se que o procedimento executivo proposto para moldagem de cascas com forma livre pode, com pequenas melhorias, ser utilizado na execução de estruturas semelhantes, mesmo com dimensões maiores, compondo-se, dessa maneira, um processo tecnológico viável. / Concrete shell roofs are very efficient structures when designed to support the loads mainly by membrane forces. Nowadays, there are numerical methods that can be used to determine the suitable shell shape, once it is given the loading and the boundary conditions, with a great variety of these parameters, thus creating the so called free form shells. When applying these shell shapes at practical situations, using conventional concrete construction technology, problems appear because of their very complex geometrical characteristics. Sandwich type construction and shotcrete have been seen in this work as alternatives to solve many construction problems involved with free form shell construction. It is propposed that conceptual design of free form shells, with basis on computational methods, be applied together with a adequate construction method to define a design methodology. Results of the application of numerical methods for shell shape generation are presented, as well as data that can be used when apllying these shell shapes in roof design. Two prototypes were built by applying mortar on ligthweight curved panels fixed between two steel meshs. The results of a loading test performed on one of these prototypes are described and compared with those obtained in a numerical simulation. The prototype proved to be so stiff, beware the fact that the thin faces of the sandwich section did not have rigid shear connections. One believes that there are sufficient data to ensure that the proposed construction method is very suitable to cast free form shell roofs and so it can be used, with few improvements, even on large span structures.

In the United States, an aging and overburdened urban infrastructure has become a substantial challenge for civil engineers. Among these challenges, systems for stormwater management are of significant concern, considering their direct impact on environmental quality, local ecosystems, and the hydrologic cycle. Given the high costs for rehabilitation of traditional stormwater infrastructure in urban settings, low impact, or "green" development strategies have become critical components in plans for meeting future stormwater management goals. In particular, New York City (NYC) has pledged $1.5 billion over the next 20 years to improve environmental quality through the mitigation of urban runoff, where utilization of green infrastructure is a primary goal. Cost effective implementation of this, and similar plans around the world, requires comprehensive understanding of green infrastructure functionality. In response, this dissertation investigates the stormwater management potential of full-scale green roofs in NYC through lenses of observation, modeling, and design. Exploration of this topic has resulted in new findings which quantify the: influence of dominant environmental and physical properties on green roof hydrologic performance, envelope of potential green roof rainfall capture in NYC, and predictive efficiency of contemporary hydrologic models for green roof assessment. This work has also lead to new methods for the: extension of green roof observations to account for the influence of rainfall distribution, parameterization of green roof hydrologic processes, and prediction of full-scale green roof rainfall capture in advance of construction. Going forward, these findings and methods are useful for informing green roof policy, planning, and design; where, in particular, this information supports the development of green roof policies that correlate to specific stormwater management goals. In summation, the characterization of green roof stormwater management in NYC, as presented in this dissertation, has contributed to the understanding of, among other topics, green roof design, urban stormwater management, hydrologic modeling, and the broad interdisciplinary field of urban ecological systems.

The conversion of natural landscapes for human use over the past century has led to significant ecological consequences. By clearing tropical forests, intensifying agriculture and expanding urban centers, human actions have transformed local, regional and global hydrology. Urban landscapes, designed and built atop impervious surfaces, inhibit the natural infiltration of rainfall into the subsurface. Deforestation, driven by the demand for natural resources and food production, alters river flow and regional climate. These land cover changes have manifested into a number of water management challenges, from the city to the watershed scale, and motivated investment into landscape re-greening programs. This movement has prompted the need for monitoring, evaluation and prediction of the hydrological benefits of re-greening. The research presented in this dissertation assesses the contribution of different re-greening strategies to water resources management, from multiple scales. Specifically, re-greening at the city scale is investigated through the study of vegetated rooftops (green roofs) in a dense urban environment. Re-greening at the watershed scale is investigated through the study of forest regeneration on deforested and ecologically degraded land in the tropics. First, the benefits of city re-greening for urban water management are investigated through monitoring and modeling the hydrological behavior of a number of green roofs in New York City (NYC). Influence of green roof size and rainfall characteristics on a green roof’s ability to retain/ detain rainwater are explored and the ability of a soil infiltration model to predict green roof hydrology is assessed. Findings from this work present insight regarding green roof design optimization, which has utility for scientific researchers, architects, and engineers. Next, a cost effective tool is developed that can be used to evaluate green roof hydrologic performance, citywide. This tool, termed the Soil Water Apportioning Method (SWAM), generates green roof runoff and evapotranspiration based on minimally measured parameters. SWAM is validated using measured runoff from three extensive green roofs in NYC. Additional to green roofs, there is potential for SWAM to be used in the hydrologic performance evaluation of other types of green infrastructure, making SWAM a relevant tool for city planners and agencies as well as for researchers from various disciplines of study. Finally, the impact of degraded landscape re-greening is investigated using a case study of 15 watersheds in Puerto Rico that have experienced extensive reforestation. The study provides evidence of improved soil conditions following reforestation, which in effect positively impacts streamflow generation processes. Findings from this work fill a gap in knowledge regarding the hydrological benefits of forest regeneration in mesoscale watersheds and provide guidance for future investment into reforestation programs. Land cover will inevitably continue to change to meet the needs of a growing and increasingly urban population. Yet there is potential to offset some of the ecological effects – especially those on hydrology – that result from land cover change. As a whole, this dissertation aims to contribute knowledge that can be used to make the re-greening of altered landscapes more realizable.

Urban stormwater runoff from impervious surfaces reduces water quality and ecological diversity in surrounding streams. The problem is exacerbated in older cities with combined sewer systems like New York City, where roughly 30 billion gallons of untreated sewage and stormwater runoff are combined and dumped into the New York harbor annually. Rain gardens and green roofs are designed to naturally manage stormwater, but both performance data and design guidance are limited. In particular, rain gardens are not optimized for nutrient removal, and US green roofs are commonly planted with non-native vegetation, which may not be optimized for water retention. The first of three studies in this dissertation investigates the overall effect of rain gardens on nutrient removal. Engineers have found there to be tradeoffs between rain garden designs that overall favor greater water retention and those that favor removal of pollutant nutrients, as efficient nutrient removal requires designs that drain slowly, and thus absorb less stormwater. Despite these opposing concerns, this dissertation has found that rain gardens constructed in areas with combined sewer systems should focus on water retention, as the benefits of treating increased amounts of water outweigh admitted downsides, such as the leaching of pollutant nutrients contained in rain garden soil. The second study investigates how nutrient pollution can be reduced in rain gardens. To do this, it quantifies the rate that the rain garden’s soil creates nitrogen pollution, by converting nitrogen from organic to inorganic forms, as inorganic nitrogen is more readily washed out of the soil and into water bodies. Conversely, it also quantifies the amount of nitrogen consumed by plants and also nitrogen emitted in gas form. It then uses the results to construct an overall nitrogen mass balance. The results indicate that the soil used to build rain gardens is in fact too nitrogen rich; inorganic nitrogen supplied by the decomposition of organic nitrogen and by stormwater runoff is far greater than required to maintain vegetative health for rain garden plants. The study concludes that altering rain garden soil specifications could reduce nitrogen pollution. The third study finds that “industry-standard” green roofs planted with drought-tolerant Sedum vegetation might not capture as much stormwater as “next-generation” native systems with irrigation and smart detention. Specifically, the study provides crop coefficients demonstrating reduced evapotranspiration in drought tolerant green roof plants compared to native plants. It also found a native roof’s stormwater capture increased with irrigation and the use of a smart runoff detention system, which automatically reduced the volume of water in the cistern that captures roof runoff in advance of a predicted storm. US government agencies are launching multi-billion dollar greening initiatives that include rain gardens and green roofs designed to manage volumes of stormwater runoff. The research here can assist in quantifying performance and improving green infrastructure designs.

Submitted by VANESSA JORDÃO MARCATO FERNANDES null (vanessamarcato@yahoo.com.br) on 2017-01-30T18:15:29Z No. of bitstreams: 1 fernandes_vjm_tese.pdf: 25329126 bytes, checksum: 92c837eb39ae9af74c15ccf278cd2a84 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-03T16:39:11Z (GMT) No. of bitstreams: 1 fernandes_vjm_dr_prud.pdf: 25329126 bytes, checksum: 92c837eb39ae9af74c15ccf278cd2a84 (MD5) / Made available in DSpace on 2017-02-03T16:39:11Z (GMT). No. of bitstreams: 1 fernandes_vjm_dr_prud.pdf: 25329126 bytes, checksum: 92c837eb39ae9af74c15ccf278cd2a84 (MD5) Previous issue date: 2016-12-19 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Esse trabalho propõe o desenvolvimento de um método para a extração automática de contornos de telhados de edifícios com a combinação de dados de Varredura a LASER Aerotransportado (VLA) e dados fotogramétricos e campos aleatórios de Markov (MRF). Inicialmente, um Modelo Digital de Superfície normalizado (MDSn) é gerado através da diferença entre o Modelo Digital de Superfície (MDS) e o Modelo Digital de Terreno (MDT), obtidos a partir da nuvem de pontos LASER. Em seguida, o MDSn é segmentado para a obtenção dos polígonos que representam objetos altos da cena. Esses polígonos são projetados na imagem para restringir o espaço de busca para a segmentação da imagem em regiões. Esse processo possibilita a extração de polígonos na imagem que representem objetos altos. O processo de identificação de contornos de telhados, em meio aos objetos altos detectados na imagem, na etapa anterior, é realizado através da otimização de uma função de energia estabelecida com base em MRF que modela propriedades específicas de contornos de telhados de edifícios. No modelo MRF são utilizados tanto os polígonos extraídos da imagem quanto os extraídos dos dados VLA. A função de energia é otimizada pelo método Algoritmo Genético (AG). O método proposto nesse trabalho foi avaliado com base em dados reais - imagens aéreas de alta resolução e dados VLA. Os resultados obtidos na avaliação experimental mostraram que a metodologia funciona adequadamente na tarefa de extrair os contornos de telhados de edifícios. A função de energia proposta associada ao método de otimização AG diferenciou corretamente os contornos de telhados de edifícios dos demais objetos altos presentes nas cenas. Os contornos de telhados extraídos apresentam boa qualidade, o que é evidenciado por meio dos índices de completeza e correção obtidos pela avaliação numérica. Com base nos índices médios obtidos para cada experimento, têm-se as médias de completeza e correção para os experimentos iguais a 90,96% e 98,99%, respectivamente. Os valores máximos de completeza e correção são de 99,19% e 99,94%, respectivamente, e os valores mínimos de 78,08% e 97,46%, respectivamente. Os menores valores de completeza estão associados às áreas de oclusão por vegetação e presença de sombras. / This paper proposes a method for the automatic extraction of building roof contours through a combination of Airborne Laser Scanner (ALS) and photogrammetric data, and Markov Random Field (MRF). Initially, a normalized digital surface model (nDSM) is generated on the basis of the difference between the digital surface model and the digital terrain model, obtained from the LiDAR point cloud. Then the nDSM is segmented to obtain the polygons representing aboveground objects. These polygons are projected onto image to restrict the search space for image segmentation into regions. This process enables the extraction of polygons in the image representing aboveground objects. Building roof contours are identified from among the aboveground objects in the image by optimizing a Markov-random-field-based energy function that embodies roof contour specific properties. In the MRF model are used both polygons extracted from image and from ALS data. The energy function is optimized by the Genetic Algorithm (GA) method. The method proposed in this work was evaluated based on real data - high-resolution aerial images and ALS data. The results obtained in the experimental evaluation showed that the methodology works adequately in the task of extracting the contours of building roofs. The proposed energy function associated with the GA optimization method correctly differentiated the building roof contours from the other high objects present in the scenes. The extracted roof contours show good quality, which is evidenced by the indexes of completeness and correctness obtained by numerical evaluation. Based on the mean indexes obtained for each experiment, the average completeness and correctness for the experiments were equal to 90.96% and 98.99%, respectively. The maximum completeness and correctness values are 99.19% and 99.94%, respectively, and the minimum values are 78.08% and 97.46%, respectively. The lowest values of completeness are associated to the vegetation occlusion areas and presence of shadows. / FAPESP: 2012/22332-2

Au cours de notre ère dite « Anthropocène » et caractérisée par l’urbanisation, la biodiversité est fortement contrainte. Il s’agit d’un problème important car elle est considérée comme le principal moteur du fonctionnement des écosystèmes et comme une source de services écosystémiques. Les toits verts sont un exemple de nouveaux écosystèmes au sein de l’environnement urbain. Ils constituent de nouveaux habitats et peuvent alors limiter la perte de biodiversité en ville. Ils offrent de plus d’autres services écosystémiques comme la régulation thermique, la gestion des eaux pluviales, ainsi qu’une certaine valeur esthétique. Dans cette thèse, nous mettrons notamment l’accent sur les toits verts dit "extensifs" (profondeur du substrat < 20 cm) car ils ont une gamme d'applications plus large et sont plus durables (car autonomes et nécessitant donc moins de maintenance).Dans l’Europe du Sud (région Méditerranéen), les performances des toits verts extensifs sont plutôt faibles, probablement à cause de l'effet des fortes températures et de la sécheresse estivale. On peut même s’attendre à une augmentation du niveau de stress des végétaux des toits verts à cause du changement climatique. La mise en place de systèmes d’irrigation pourrait alors aider en favorisant la croissance des plantes et leur survie. Cependant, cet aménagement est souvent perçu comme une option non soutenable car l'accès à l’eau est limité en région méditerranéenne. Au cours de la période estivale, la pénurie d’eau sera de plus encore plus grave du fait du changement climatique. Par conséquent, une augmentation du nombre de recherches menées sur ce sujet est nécessaire afin de sélectionner les espèces végétales les plus adaptées aux toits verts extensifs non irrigués. Il est également nécessaire d’adapter les éléments structurels des toits extensifs pour mieux répondre aux exigences de ces plantes. Pour les pays plus au nord, avec des climats plus froids (par exemple en climat tempéré maritime), les scénarios de changements climatiques prévoient également une augmentation des températures et des précipitations plus erratiques. Les entreprises de toits végétalisés dans ces régions bénéficieront donc également des résultats d’une telle recherche.L’objectif principal de cette thèse était d’élaborer et de tester un nouveau concept pour la réalisation de toits verts extensifs, comprenant notamment la sélection de la végétation et des éléments de structure (substrat). Le travail est basé sur l’hypothèse de « l’habitat modèle », qui énonce qu’il faut cibler les habitats naturels possédant des caractéristiques similaires aux toits verts extensifs afin de trouver des espèces végétales les plus appropriées. La biodiversité en région Méditerranéenne est très riche et il y a plusieurs habitats qui ressemblent plus au moins aux conditions des toits verts extensifs (sols calcaires et superficielles, drainage rapide, pauvreté en nutriments, fluctuations de température, vents forts). Notre hypothèse est alors qu’il serait possible de trouver des plantes possédant des potentiels pour être introduites sur des toits verts extensifs. Parce que la région Méditerranéenne est très étendue, le sud de la France a été sélectionné comme région d’études. Nous concluons que la végétation méditerranéenne peut être une source d'inspiration pour le développement et l’amélioration de la conception des toits verts extensifs, que ce soit pour le climat méditerranéen actuel ou pour d’autres climats sous l'effet futur des changements climatiques prévus. Un choix de plantes appropriées est alors essentiel, ainsi que la conception en termes de techniques d’irrigation durable, de profondeur et composition du substrat et aussi des possibilités de rétention de l’eau. De plus, il existe encore de nombreuses voies pour la réalisation de recherches supplémentaires qui contribueront à la mise en place de toits verts avec une biodiversité plus importante. / In an era of urbanization, biodiversity is under pressure more than ever. Biodiversity is considered a major driver of ecosystem functioning and the provision of ecosystem services. Green roofs, a prime example of urban novel ecosystems, offer habitats and can hence mitigate some biodiversity loss in cities. Apart from biodiversity, green roofs also offer other ecosystem services, such as thermal regulation, stormwater management, and aesthetic and amenity value. Here we focused on extensive green roofs (substrate depth < 20 cm) as these can be applied widely and are more durable (i.e. less maintenance, self-sustaining). In southern Europe (Mediterranean), the performance of (extensive) green roofs is rather low, probably due to the elevated temperatures and summer drought. One may expect that plant stress on green roofs will further increase as a result of climate change. Irrigation could help plant growth and survival. However, irrigation is often perceived as an unsustainable practice, as water is already a limiting factor in many regions and climate change will lead to an even more severe water scarcity during summer. Therefore, research is needed to select plant species suitable for Mediterranean (unirrigated) extensive green roofs, and to adapt green roof design to meet the requirements of the selected plant species. More northern countries with colder climates (e.g. temperate maritime climate) will also face higher temperatures and erratic precipitation events as a result of climate change. The green roof industries located in these regions will hence also benefit from the outcome of such research. The main goal of this thesis was to elaborate and test a new concept for extensive green roof design, comprising both plant selection and design elements. The work is based on the habitat template theory, which states that natural habitats with similar characteristics as extensive green roofs should be targeted when searching for suitable plant species. Mediterranean regions are a hotspot of biodiversity and contain many habitats that match to some extent the conditions on extensive green roofs (e.g. shallow, free draining, nutrient poor and calcareous soils, high temperature fluctuations, windy). We hence hypothesized that it would be possible to find potential plant species for use on extensive green roofs. Because of practical reasons we selected the southern part of France as study region. At the end of this thesis, we conclude that natural habitats in the Mediterranean region can definitely inspire us as a source for development and improvement of extensive green roof design, whether this is for the current Mediterranean climate itself or for other climates under predicted climate change. Appropriate vegetation choice is essential, as well as the design in terms of sustainable irrigation techniques, appropriate substrate depth and composition, and water retention possibilities. Finally suggestions for further research were made.

Neste trabalho apresenta-se um estudo do comportamento estrutural de cestas protendidas, tendo em vista a sua utilização em coberturas pênseis de grandes áreas livres. A partir da Técnica do Meio Contínuo obtêm-se as equações que permitem analisar as cestas protendidas quanto a esforços e deslocamentos. Fazem-se considerações sobre o sistema de equações encontrado visando a sua resolução mediante o emprego de programa computacional como instrumento de cálculo. Apresentam-se exemplos numéricos e os resultados são comparados com os obtidos em outros trabalhos. Fazem-se algumas considerações a respeito do projeto e do cálculo de cestas protendidas, além de algumas indicações sobre a continuidade da pesquisa. / This work presents a continuous medium method analysis of cable nets and their applications as suspended roofs for large free spans. lnitially the theory of the method is presented and later applied to get the system of differential equation that represents the problem. Finally this system is numerically solved with computational procedures. Some examples are presented and the results compared with those obtained with others methods and numerical procedures. Some analysis and design considerations and further developments in this subject are also included.