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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.
221

Architettura e verità. Emil Steffann architetto di chiese / Architecture and truth. Emil Steffann architect of churches / Architektur und Wahreit. Emil Steffann: Kirche Bauen

Grisi, Tinuccio <1964> 22 April 2013 (has links)
La ricerca pone al suo centro lo studio dell'opera architettonica di Emil Steffann (1899-1968) la cui produzione realizzata consta, nel breve arco temporale che va dal 1950 al 1968, del ragguardevole numero di trentanove chiese, rappresentando un caso emblematico di progettazione e costruzione di edifici per il culto cristiano in grado di raffigurarne concretamente i principi fondativi liturgici, estetici e morfologici. L'architettura di Steffann, profondamente ispirata dallo spirito religioso, legata a figure primigenie che plasmano lo stare-insieme della comunità nella qualità corporea della materia, dove la presenza liturgica e monumentale si esprime nel silenzio e nella disponibilità di uno spazio circoscritto dai muri e direzionato dalla luce, concorre a definire nell'oggettivo amore per il vero la percezione estetico-teologica e la poetica formativa che connaturano, a nostro parere, progetto e segno della chiesa. Il testo concretizza il primo studio monografico completo di questo corpus architettonico e si basa sulla ricognizione diretta delle opere di Steffann; ne è derivata una narrazione non conseguente a un ordine cronologico o di presupposta importanza degli edifici, bensì che ricerca ed evidenzia corrispondenze tra nodi di una rete ideativa la quale, con diversi gradi di finitezza, in punti non sempre omogenei del tempo e dello spazio, denota un'esperienza autentica del comporre e del costruire. Il racconto individua gli oggetti architettonici, ne discute la consistenza aprendosi a riferimenti altri (in particolare il pensiero ecclesiologico-liturgico di Romano Guardini e quello estetico-teologico di Hans Urs von Balthasar) in grado di illuminarne la genesi e la manifestazione, li lega infine in sequenze analogiche. Una serie di tavole fotografiche originali, parte ineludibile e integrante della ricerca, testimonia dello stato attuale dei luoghi, connotando ulteriormente l'aspetto info-rappresentativo della loro composizione architettonica. In chiusura, la sintesi architetturale vuole essere uno strumento di verifica e progetto, quindi di trasposizione futura, correlato all'elaborazione documentaria. / The research puts at its heart the study of the architectural work of Emil Steffann (1899-1968) whose builded production consists, in the short time 1950-1968, in the very considerable number of thirty-nine churches, representing an emblematic case-study of design of buildings for Christian worship, able to show its liturgical, aesthetic and morphological founding principles. The architecture of Steffann - deeply inspired by the religious spirit, linked to primigenee figures that shape the stay-together of the community in the corporeal quality of the material, where the liturgical and monumental presence is expressed into the silence and availability of the space enclosed by walls and oriented by the light - helps to define, in the objective love for the true, the aesthetic-theological perception and the shaping poetic that ingrain, in our opinion, the project and the sign of the church. The text achieves the first comprehensive monograph of this architectural whole, based on the direct survey of the works of Steffann; it arise a story that does not depend on a chronological order or presumed prominence of the buildings, but that research and highlights the correspondences between nodes of a creative network which - with varying degrees of completeness, in not always homogeneous points of time and space - denotes an authentic experience of composing and building. The story identifies the architectural objects, discusses their consistency (to open itselt to other references, particularly the ecclesiological and liturgical thinking of Romano Guardini and the theological-aesthetic of Hans Urs von Balthasar, able to illuminate their genesis and manifestation), then binds them in analogical sequences. A series of original photographic plates, integrant and unavoidable part of the research, shows the current state of the places, further connoting the info-representative aspect of their architectural composition. The architectural synthesis aims to be a testing and design tool.
222

The effect of two-dimensional squat elements on the seismic behavior of building structures / La risposta sismica di elementi portanti bidimensionali

Palermo, Michele <1985> 19 May 2014 (has links)
This thesis reports a study on the seismic response of two-dimensional squat elements and their effect on the behavior of building structures. Part A is devoted to the study of unreinforced masonry infills, while part B is focused on reinforced concrete sandwich walls. Part A begins with a comprehensive review of modelling techniques and code provisions for infilled frame structures. Then state-of-the practice techniques are applied for a real case to test the ability of actual modeling techniques to reproduce observed behaviors. The first developments towards a seismic-resistant masonry infill system are presented. Preliminary design recommendations for the seismic design of the seismic-resistant masonry infill are finally provided. Part B is focused on the seismic behavior of a specific reinforced concrete sandwich panel system. First, the results of in-plane psuudostatic cyclic tests are described. Refinements to the conventional modified compression field theory are introduced in order to better simulate the monotonic envelope of the cyclic response. The refinements deal with the constitutive model for the shotcrete in tension and the embedded bars. Then the hysteretic response of the panels is studied according to a continuum damage model. Damage state limits are identified. Design recommendations for the seismic design of the studied reinforced concrete sandwich walls are finally provided.
223

Carlos Martí Arís e i suoi eteronimi. Vocazione all'anonimo / Carlos Martí Arís and his heteronimies. Vocation for anonymity / Carlos Martí Arís y sus heterónimos. Vocación de anónimo

Licitra, Fabio <1971> 10 June 2014 (has links)
Questa ricerca indaga la prospettiva investigativa di Carlos Martí Arís. È stato assunto il campo d’azione da lui prediletto, ovvero l’articolato rapporto che in architettura si instaura tra teoria e pratica, comprensivo delle svariate ricadute nel mondo dell’arte e della produzione umana in genere, che fanno del progetto architettonico un campo disciplinare complesso. La sua figura è però assunta in modo strumentale, come grimaldello per addentrarsi in un articolato ambito culturale, che se da un lato coincide con la sua città, Barcellona, dall’altro la trascende grazie a quei “ponti della conoscenza” che CMA interrottamente ha teso al suo intorno. Ci riferiamo alla sua costruzione teorica destinata a consolidare la storica reciprocità tra Italia e Spagna, le cui tematiche urbane e tipologiche ne sono la base, Milano e Barcellona ne sono gli estremi. Ci riferiamo al suo sguardo sull’esperienza del Movimento Moderno e il relativo tema della residenza. Ci riferiamo alla sua naturale vocazione al silenzio, che si oppone al fragoroso rumore della contemporaneità e affianca la discreta parola del mestiere: un modo per porsi all’ascolto. All’ascolto dell’altro e del mondo. Ci riferiamo, insomma, alla sua idea di architettura intesa come «territorio dissodato da tempi remoti»; come trama di corrispondenze sincroniche tra terre, tempi, fatti, uomini, vicini e lontani: condizione ideale per chi voglia disciogliere il proprio lavoro nei labirintici sentieri del mondo, indifferente al rischio di perdersi nell’oblio. Oggi, in cui il progetto architettonico risulta sempre più spesso veicolo di soggettive e arbitrarie sperimentazioni formali, la lezione di CMA indica una via d’uscita: un mo(n)do condiviso che all’arroganza opponga la discrezione, che persuada a celarsi nella tradizione e a porsi umilmente all’ombra dei maestri. Tradizione e Maestri, Eteronimi e Nomi, complementarità a cui CMA affida il suo progetto di anonimato, sovrapersonale e ostinatamente teso a rilevarne le relazioni inedite. / This research enquires into the investigating perspective of Carlos Marti Arias. To this effect his privileged field of action is framed, more concretely the articulated link that is established in architecture between theory and practice, covering also the various incursions in the world of art and human production in general, all of which turns architectonic project into a complex disciplinary field. The approach to his figure is instrumental, this is, it is considered as the key which allows the entrance into an articulated cultural environment which, if on one side it coincides with his town Barcelona, on the other side it transcends it thanks to those “ bridges of knowledge” that occasionally CMA constructed towards the world around him. We are here referring to his theoretical construction meant to consolidate such reciprocity as exists between Italy and Spain, its base being their urban and typological thematic, the extremes being Milan and Barcelona. We are speaking of his natural vocation for silence that he opposes to the deafening noise of the contemporary and that he couples with the discreet word of craft. All things considered, we do refer to his idea of architecture as “ labored world of times past”, as a net of correspondence among the land, times, events, human beings, be they nearby or far away; these being the ideal conditions for those who wish to insert their own work in the maze of the world’s paths, notwithstanding the risk of being lost in oblivion. Tradition and Masters, Heteronomy and Names, complementary worlds to which CMA entrusts his Project for anonymity, a supra personal Project decidedly tending to outline the inedited links it contains. / Este trabajo indaga en la perspectiva investigadora de Carlos Martí Arias. A tal efecto, se delimita su campo de acción predilecto, más concretamente el nexo articulado que en arquitectura se instaura entre la teoría y la práctica. Su figura se enfoca de modo instrumental, esto es, como clave para adentrarse en un ámbito cultural articulado, que, si bien por un lado coincide con su ciudad, Barcelona, por el otro la trasciende gracias a aquellos “puentes del conocimiento” que ocasionalmente CMA tendía en su entorno. Nos referimos aquí a su construcción teórica destinada a consolidar aquella reciprocidad existente entre Italia y España, cuya base la constituyen sus temáticas urbanas y tipológicas, siendo Milán y Barcelona los extremos. Nos referimos a su visión sobre la experiencia del Movimiento Moderno y al tema relativo de la residencia, para él prioritario. Nos referimos a su natural vocación al silencio que opone al fragoroso ruido de la contemporaneidad y pone a la par la discreta palabra del oficio. Nos referimos en resumen a su idea de la arquitectura entendida como “territorio roturado de los tiempos remotos”, como trama de correspondencia entre tierra, tiempo, hechos, hombres, cercanos o lejanos; condiciones ideales para quienes desean disolver su propio trabajo en el sendero laberíntico del mundo, indiferentes al riesgo de perderse en el olvido. Hoy las lecciones de CMA indican una vía de salida: un mundo, un modo, compartido en que a la arrogancia se opone la discreción, que incita a acercarse a la tradición y a abrigarse humildemente en la sombra de los maestros. Tradición y Maestros, Heteronimia y Nombres, complementariedades a las cuales CMA confía su proyecto de anonimato, supra personal y obstinadamente tendente a poner en él de relieve las relaciones inéditas.
224

Le architetture ecclesiali nei siti d'altura alpini

Salvador, Isabella January 2011 (has links)
La ricerca punta a definire una metodologia operativa ad ampia scala territoriale che possa catalogare, studiare e valutare lo stato di conservazione dei manufatti architettonici emergenti caratterizzanti il territorio trentino d’altura. La conoscenza e lo studio dell’ingente patrimonio architettonico del passato, soprattutto quello ecclesiastico, è finalizzato alla concreta definizione di modus operandi specifici per il recupero di materiali e tecnologie costruttive in architetture che presentano una notevole stratificazione storica artistica – materica – statica, onde evitare le omogeneizzazioni e le semplificazioni negli interventi di recupero che si sono verificati negli ultimi decenni, per la mancanza di conoscenze approfondite soprattutto in particolari ambiti montani. Lo studio è strettamente connesso ad uno dei grandi progetti 2006 della Provincia Autonoma di Trento, il progetto APSAT (Ambiente e Paesaggio dei Siti Altura Trentini), finalizzato alla rivalutazione dei siti d’altura alpini mediante l’analisi e la comprensione dei complessi sistemi antropici che si sono sviluppati e stratificati nel tempo fino ad arrivare all’attuale assetto socio - economico e culturale - territoriale. E' stato necessario assumere un’area campione, la Val di Gresta (Vallagarina), che per le sue contenute dimensioni geografiche ben si presta ad una lettura approfondita e multiscala. Lo studio, articolato su più livelli e su più ambiti di ricerca, ha individuato le relazioni tra manufatti e ambiente naturale, tra diversi tipi edilizi nel loro rapporto con le infrastrutture e il paesaggio, determinando input di trasformazione comuni a tutti i sistemi antropici.
225

Sunspaces for passive building heating: calculation models and utilization of empirical data

Passerini, Francesco January 2012 (has links)
The thesis deals with sunspaces, considered as a particular passive solar system. Solar systems exploit solar radiation in order to decrease the use of non-renewable energy sources. Therefore their importance is both environmental and economic. According to “The passive solar energy books” (1979) of Edward Mazria the difference between “active systems” and “passive systems” is that in the latter the heat flows happen without mechanical equipment. The present research focuses on the reduction of winter energy requirements due to the presence of a sunspace, it analyses the involved physical phenomena, and it considers tools to design sunspaces and to optimize them from the point of view of energy requirements. Particular attention is given to the quasi-steady-state methods, which are the most used by the designers. The thesis critically analyses calculation methods, identifies their problematic aspects and provides some indications to improve the method of the technical standard EN ISO 13790:2008. As well as by the theoretical part, in the research a fundamental role is played by experimental campaigns. In fact, empirical data have been collected in relation both to existing sunspaces and to sunspaces which were specifically constructed for the research. Two sunspaces, one having the dimensions of a small room and the other one which is its scale model, with halved dimensions, were created and were the object of an experimental campaign. This experimental study has allowed to observe how the physical behaviour of sunspaces changes by changing their dimensions and to achieve a deep comprehension of sunspaces through quantitative analyses of involved physical quantities. A virtual model of the sunspaces was created and validated. Because of the long renovation cycle for buildings, the improvement of the energy performance of existing buildings is fundamental. That is the reason why part of the research concerns the refurbishments of verandas which are closed with elements having a large glazed surface. The concept is the same as for the sunspaces: the presence of an adjacent not heated space which works as “solar collector” can decrease the heating requirements. An existing building in Freiburg (Germany), which was renovated between 1997 and 1999 (among other things, by closing the veranda with windows, improving the insulation, and adding a solar air collector for the supply air entering the veranda and a mechanical air extraction system), was monitored (in collarboration with Fraunhofer ISE) and the data were analysed critically. Considering the experience with the past renovation, design proposals for future refurbishments have been considered. The energy performances of different possibilities are calculated and compared among them. Attention is paid to thermal insulation, to exploitation of the solar radiation and to ventilation strategies (also mechanical and integrated with heat recovery systems). A guided procedure for the proper design of sunspaces is presented. Its goal is to present clearly and with a logical sequence what aspects the designers have to take into account to design sunspaces properly. Both new constructions and refurbishments are considered. Aspects such as the relationship between building shape and heating requirements, local context, insulation, thermal inertia, overheating, ventilation, and so on are dealt with. The technology to build a sunspace is simple, but a rigorous study of its behaviour is complex. Future researches about the thermal behaviour of sunspaces could develop further the possibility to improve the quasi-steady-state methods, taking in consideration, also from a quantitative point of view, a lot of different cases. The utilization of CFD software, in order to better estimate the convective heat coefficients and to evaluate the ventilation from a sunspace, could be another development of this subject.
226

Life Cycle Thinking: Strategies for Sustainable Renovation of Existing Buildings

Grillo, Maria Cristina January 2014 (has links)
The project focuses on developing strategies for interventions of sustainable renovation, with the awareness that re-using existing buildings allows to reduce the impact on the environment and also to maintain our cultural sources and ecosystems. The largest part of the European building stock is composed of buildings older than 30 years that will continue to account for the major portion of it also for the decades to come. These buildings are very important because of their economic, social-cultural and environmental value. Often built stock needs interventions of renovation in order to meet the actual standard of performance, both from energetic and functional point of view. Recent changes in human life style oblige to modify spaces in a quick way and this necessity has reduced the life of our buildings. For this reason it is fundamental operate on existing buildings reducing the waste production, by using the strategies of the design for de-construction and the reversible design. To do this, LCA is the best method, because it allows measuring objectively the buildings impact and the environmental benefits of renovations and also it can help in defining the most appropriate materials. This work presents the analysis of the restoration projects of two industrial buildings in a sustainability perspective. Industrial buildings were chosen as case studies because of their big sizes, good accessibility, flexible internal partitions and large pertinence areas, features which make them good candidate for rehabilitation. The focus point is how to convert this existing estate in a sustainable way, in order to reduce the need for new constructions and optimize the intrinsic qualities of forsaken industrial spaces.
227

An Optimization Index to Identify the optimal Design Solution of Bridges

Feng, Yue January 2014 (has links)
Structural optimization has become an important tool for structural designers, since it allows a better exploitation of material, thus decreasing structure self-weight and saving material costs. Moreover, it helps the designer to find innovative design solutions and structural forms that not only better exploit material but also give the structure higher aesthetic value from an architectural point of view. When applied to real scale structures like bridges, this approach leads to the definition of voids patterns delimiting regions where fluxes of force migrate from force application point to boundary regions and suggests innovative layouts without renouncing to formal and structural aspects. Nevertheless, the criticality of this powerful tool is related to the ease of defining entire families of possible candidate solutions, by modifying input volume reduction ratio to reduce structural weight as much as possible or defining several starting trial solutions based on the judgment of designer. In this case, structural optimization still leads to the best material distribution, but finding the best compromise between material saving and structural performance is a designer choice. To face this aspect, a global optimization index (GOI) has been defined and applied to the structural optimization of a steel-concrete arch bridge built is San DonÃ&nbsp; in the province of Venice, Italy. On the basis of this work, a generalized version of the optimization index is proposed and its analytical formulation is discussed in detail in this thesis. The application of proposed optimization index is extended from topology optimization to other optimization techniques. Moreover it allows not only to identify best candidate solution originated by a unique reference model, but even comparing structural performances between candidates solution derived by several starting trial solutions. Through structural optimization procedure performed on three different type bridges, namely footbridges supported by concrete shell, Calatrava Bridge (steel arch bridge) and two cable-stayed bridges, the effectiveness of proposed optimization index is validated. The results show that the proposed optimization index provides to the designer a mathematical procedure able to highlight the best choice among several candidate solutions obtained by the optimization procedure. With the proposed optimization index, a suitable score for each design solution of specific starting layout is assigned, therefore the best overall layout solution which is the best compromise between material saving and structural performance can be highlighted among single-family multi-solutions or multi-families or multi-solutions.
228

Rivers Hydromorphological Characterization from High Resolution Remotely Sensed Data

Niroumand Jadidi, Milad January 2017 (has links)
Remote sensing techniques could enable remarkable advances in characterizing rivers hydromorphology by providing spatially and temporally explicit information. Remote mapping of hydromorphology can play a decisive role in a wide range of river science and management applications including habitat modeling and river restoration. High resolution satellite imagery (HRSI) has recently emerged as potentially powerful means of mapping riverine environments. This research aims to develop advanced methodologies for processing HRSI to map and quantify a set of key hydromorphological attributes including: (1) river boundaries, (2) bathymetry and (3) riverbed types and compositions. Boundary pixels of rivers are subject to spectral mixture that limits the accuracy of river areas extraction using conventional hard classifiers. To address this problem, unmixing and super resolution mapping (SRM) are focused as two steps, respectively, for estimation and then spatial allocation of water fractions within the mixed pixels. Optimal band analysis for NDWI (OBA-NDWI) is proposed to identify the pair of bands for which the NDWI values yield the highest correlation with water fractions. The OBA-NDWI then incorporates the optimal NDWI as a predictor of water fractions through a regression model. Water fractions obtained from the OBA-NDWI method are benchmarked against the results of simplex projection unmixing (SPU) algorithm. The pixel swapping (PS) and interpolation-based algorithms are applied on water fractions for SRM. In addition, a simple modified binary PS (MBPS) algorithm is proposed to reduce the computational time of the original PS method. Water fractions obtained from the proposed OBA-NDWI method are demonstrated to be in good agreement with those of SPU algorithm (R2=90%, RMSE=7% for WorldView-2 (WV-2) image and R2=87%, RMSE=9% for Geoeye image). The spectral bands of WV-2 provide a wealth of choices through the proposed OBA-NDWI to estimate water fractions. The interpolation-based and MBPS methods lead to sub-pixel maps comparable with those obtained using the PS algorithm, while they are computationally more effective. SRM algorithms improve user/producer accuracies of river areas about 10% with respect to conventional hard classification. This research introduces multiple optimal depth predictors analysis (MODPA) that combines previously developed depth predictors along with other measures such as the intensity components of HSI color space. To avoid over-fitting of the linear model, statistically optimal predictors are selected based on one of partial least square (PLS), stepwise and principal component (PC) regressions. The primary focus of this study is on shallow and clearly flowing streams where substrate variability could have pronounced effect on depth retrievals. Spectroscopic experiments are performed in controlled condition of a hydraulic laboratory to examine the robustness of bathymetry models with respect to changes in bottom types. Further, simulations from radiative transfer modeling are used to extend the analysis by isolating the effect of inherent optical properties (IOPs) and also by investigating the performance of bathymetry models in optically complex and also deeper streams. Bathymetry of Sarca, a shallow river in Italian Alps, is also mapped using a WorldView-2 (WV-2) image where the atmospheric compensation (AComp) product is evaluated for the first time. Results indicate the robustness of multiple-predictor models particularly MODPA rather than single-predictor models such as optimal band ratio analysis (OBRA) with respect to heterogeneity of bottom types, IOPs and atmospheric effects. This study suggests extra predictors when the multiple regression is assisted with an optimal predictors selection process (e.g. MODPA). The extra predictors enhance the accuracy of depth retrievals particularly in optically complex waters and also for low spectral resolution imagery (e.g. GeoEye). Further, enhanced spectral resolution of WV-2 compared to GeoEye improves the bathymetry retrievals. MODPA based on PLS regression provided improvements on the order of 0.05 R2 and 0.7 cm RMSE compared to multiple Lyzenga and 0.18 R2 and 2 cm RMSE compared to OBRA using AComp reflectances of WV-2 for Sarca River with a maximum 0.8 m depth. In addition, a theoretical approach namely hydraulically assisted bathymetry (HAB) is assessed and further modified for calibration of bathymetry models that provided comparable results with the empirical calibration approach. Substrate mapping in fluvial systems has not received as much attention as that in nearshore optically shallow waters of inland and coastal areas. The research to date has been primarily based on surface spectral reflectance data without accounting for water column attenuations. This study aims at retrieving the bottom reflectances in shallow rivers and then examining the effectiveness of inferred bottom spectra in mapping of substrate types. Bathymetry and diffuse attenuation coefficient (kd) are derived from above-water reflectances for which some in-situ/known depths are required. Following the retrievals of depth and kd, bottom reflectances are estimated based on a water column correction method. Moreover, the efficacy of vegetation indices (VIs) is examined for making distinction among the densities of submerged aquatic vegetation (SAV) using either above-water or retrievals of bottom reflectances. This research benefits, for the first time, from three different approaches including controlled spectroscopic measurements in a hydraulic lab, simulations from radiative transfer modeling and an 8-band WordView-3 (WV-3) image. The results indicate the significant enhancements of streambed mapping using inferred bottom reflectances than using above-water spectra. This is evident, for instance, on clustering of three bottom types using simulated spectra with 20% enhancement of overall accuracy. Deep-water correction demonstrated to have most of an impact on retrievals of bottom reflectances only in NIR bands when the water column is relatively thick (&gt; 0.5 m) and/or when the water is turbid. The red-edge (RE) band of WV-3/WV-2 improves remarkably the detection of SAV densities based on the VIs either using above-water or retrieved bottom spectra. Further, the simulated spectra suggest that enhanced spectral resolution of 8-band WV-3 leads to improvements in streambed mapping compared to traditional 4-band imagery. This study demonstrated the feasibility of retrieving bottom reflectances and mapping SAV densities from space in a shallow river using the WV-3 image (user and producer accuracies of 67% and 60% in average for three levels of SAV densities). Moreover, the feasibility of mapping grain size classes is assessed using spectral information based on laboratory experiments coupled with simulations. The changes in grain sizes affect the magnitude of reflectances while the shape of spectra remains almost identical. This characteristic feature demonstrated high potentials for mapping grain size classes by retrieving the bottom reflectances. In summary, HRSI provided promising results and effective means of mapping the selected hydromorphological attributes of shallow rivers in spatially continuous and in large extents.
229

Tetti verdi: Analisi sperimentale e Modellazione numerica / Green roofs: Experimental analysis and Numerical modelling

Cipolla, Sara Simona <1983> 21 May 2015 (has links)
I tetti verdi rappresentano, sempre più frequentemente, una tecnologia idonea alla mitigazione alle problematiche connesse all’ urbanizzazione, tuttavia la conoscenza delle prestazioni dei GR estensivi in clima sub-Mediterraneo è ancora limitata. La presente ricerca è supportata da 15 mesi di analisi sperimentali su due GR situati presso la Scuola di Ingegneria di Bologna. Inizialmente vengono comparate, tra loro e rispetto a una superficie di riferimento (RR), le prestazioni idrologiche ed energetiche dei due GR, caratterizzati da vegetazione a Sedum (SR) e a erbe native perenni (NR). Entrambi riducono i volumi defluiti e le temperature superficiali. Il NR si dimostra migliore del SR sia in campo idrologico che termico, la fisiologia della vegetazione del NR determina l'apertura diurna degli stomi e conseguentemente una maggiore evapotraspirazione (ET). Successivamente si sono studiate la variazioni giornaliere di umidità nel substrato del SR riscontrando che la loro ampiezza è influenzata dalla temperatura, dall’umidità iniziale e dalla fase vegetativa. Queste sono state simulate mediante un modello idrologico basato sull'equazione di bilancio idrico e su due modelli convenzionali per la stima della ET potenziale combinati con una funzione di estrazione dell’ umidità dal suolo. Sono stati proposti dei coefficienti di correzione, ottenuti per calibrazione, per considerare le differenze tra la coltura di riferimento e le colture nei GR durante le fasi di crescita. Infine, con l’ausilio di un modello implementato in SWMM 5.1. 007 utilizzando il modulo Low Impact Development (LID) durante simulazioni in continuo (12 mesi) si sono valutate le prestazioni in termini di ritenzione dei plot SR e RR. Il modello, calibrato e validato, mostra di essere in grado di riprodurre in modo soddisfacente i volumi defluiti dai due plot. Il modello, a seguito di una dettagliata calibrazione, potrebbe supportare Ingegneri e Amministrazioni nella valutazioni dei vantaggi derivanti dall'utilizzo dei GR. / Green roofs (GRs) are an increasingly popular method for mitigating the negative environmental impacts of urbanization, however literature still shows a limited knowledge on the behavior of extensive GR under sub-Mediterranean climate. This experimental study is supported by 15 months of field monitoring activity within two large GRs located on the engineering laboratories of the University of Bologna, Italy. Firstly native perennial herbs mix (NR) and succulent Sedum mix (SR) plots were compared to each other and with a bare-bituminous membrane control plot (RR) to evaluate their hydrological behaviour and diurnal cooling effects. Both the GRs are able to reduce the runoff and the surface temperature, moreover the native mix seems to achieve a better cooling service and a higher retention capacity due to his transpiration physiology which determines greater daily evapotranspiration (ET) losses. Secondly the study investigates how the moisture content in the Sedum green roof varies during dry periods due to ET. Daily moisture loss rates were influenced by temperature, initial moisture content and vegetation growth stages. Subsequently it is demonstrated that the observed moisture content data can be accurately simulated using an hydrologic model based on water balance and two conventional Potential ET models (Hargreaves and Penman-Monteith) combined with a soil moisture function. Specific monthly correction factors have been proposed to account for differences between GR and standard reference crops during the growth stages. Finally, the retention performances of SR and RR plots were simulated continuously (12 months) using the Stormwater Management Model (SWMM) with Low Impact Development (LID) controls module (version 5.1.007). The model, calibrated and validated with the experimental data, shows satisfactory results in terms of annual simulated runoff volume. It can be, after a proper calibration, a valid tool to support engineers and administrators to evaluate the benefits deriving from the use of GRs.
230

Use of Industrial Reclaimed Filler to Modify Asphalt Mixture and Binder Performances. Advanced rheological performance evaluation and 3D DEM Modeling of bituminous binders and mastics

Mazzotta, Francesco <1986> January 1900 (has links)
The mechanical performance of an asphalt mixture is largely dependent on the properties of its constituents and by the way they reciprocally interact in the bituminous layer. In particular, the stress-strain response of the road pavements is closely related to the rheological behavior of the bituminous binder and of its interaction with the finest part of the lytic skeleton. Therefore, it is important to study in the laboratory by means of advanced rheological tests, how mastics (Bitumen-Filler Systems) and mortars (Bitumen-Filler-Sand Systems) react to dynamic loads and thermal stresses. Moreover, the understanding of the contacts mechanisms within the bitumen-filler system, through 3D micro-mechanical models, should allow for a deeper analysis of the mastic rheological behavior. Based on these considerations, in a socio-economic context in which it is necessary to reduce the environmental impact caused by the construction and maintenance of transportation infrastructures, bituminous mastics containing different reclaimed fillers from the industrial production wastes were studied. For this purpose, advanced rheological tests have been first validated and then implemented and combined with the 3D DEM models development. Results showed that the methods used to study the bituminous mastics and mortars allowed to understand the effects due to the addition of innovative and recycled fillers within the mixtures blend, highlighting as these can increase the asphalt mixture performance during its service life.

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