The research presented in this thesis was focused on timber floor diaphragms in unreinforced masonry (URM) buildings. The work was divided into two phases. The first phase was aimed at the investigation of the effects of the in-plane behavior of timber diaphragms on the global seismic response of URM buildings. The second phase was dedicated to the assessment and retrofit of timber floors, with particular attention to the out-of-plane behavior. A study on the equivalent frame method, which is a more and more appreciated masonry modeling technique, is presented. Both as-built and strengthened timber floors were addressed. In order to understand the influence of the masonry modeling method on the seismic response of URM structures when flexible diaphragms are concerned, a simplified elastic no tension method was proposed. Such method is able to describe the characteristic nonlinear behavior of masonry (due to extremely low tensile strength) by means of a series of linear analyses based on a Rankine failure criterion. An in-situ testing campaign on full-scale 100 year old timber diaphragms is presented. Both mechanical and dynamic in-plane properties of wood diaphragms were investigated. Cyclic and snap back tests were carried out thanks to an innovative ad hoc loading system, developed by means of wire ropes and steel pulleys. The loading system was designed to reproduce a realistic inertial load distribution and to be lightweight, versatile and easily relocatable from one diaphragm section to the next. The effect of different refurbishment techniques was also probed during the experimental campaign. The outcomes of a testing campaign regarding out-of-plane refurbishment techniques of existing timber floors by means of timber to timber composite structures are described. A numerical model based on the theory of composite beams with incomplete interaction, was calibrated to take into account the real load distribution and connector spacing. An original procedure to camber timber beams by employing the compression pressure generated by screw fasteners is presented. The camber deflection is attained by superposing a timber reinforcement element on top of a beam and then connecting the two elements by means of screws inserted at 45° to the beam axis. Such method which is currently patent pending, was validated using data obtained from experimental testing. A mathematical formulation was also developed to describe the cambering procedure. A specific experimental campaign was therefore performed to precisely evaluate the amount of pressure that each screw is capable of yielding. Many parameters supposed to affect the compression force, were explored through 170 tests.

The thesis aims to investigate the dynamical criticality of a pedestrian footbridge and the use of a semi-active tuned mass damper. In this respect, the work appears threefold since the first and third part regard identification of a realistic model for the damping device and semi-active control of the magneto-rheological damper. In this respect, input identification techniques are a useful tool and an aid for the control law design. As a consequence, the second part involves both input identification strategies for a dynamic system and analysis of issues related to the inherent delay. In this respect, the so called “collocation” of measurement devices with respect to the application points of the input is critical, together with the concept of kernel.

Accidental events, such as impact loading and explosions, are rare events with a very low probability of occurrence, but their effects often lead to very high human losses and economical consequences. Vulnerability of structures to the effects of local damages and its mitigation are issues widely discussed inside the scientific community. The structural property associated with such a vulnerability is named robustness. Depending on the type of the structural system and on the importance of consequences, specific design strategies can be adopted in order to ensure a robust structural response. Among them, the system redundancy, the joints and members ductility and the alternate load paths are the ones commonly adopted in case of multi-storey framed buildings. The present work focuses on the study of the behaviour of steel-concrete composite structures subjected to a column loss, and proposes a global overview to quantify the robustness of such systems subjected to this hazard scenario. The description of validated finite element models and of a new analytical tool to predict the response of flat concrete slabs subjected to large displacement are reported in this dissertation. Furthermore, important design hints for composite buildings are proposed. The starting point of the research is an experimental campaign conducted at the University of Trento. Two tests on 3D full-scale one storey composite steel-concrete frames, extracted from five storeys frames designed in accordance to the Eurocodes, were performed simulating the central column removal. The role of the beam-to-column connections and of the concrete slab for the force redistribution was investigated. The experimental data have been then taken as reference for the calibration of finite element models that allowed to conduct further numerical analyses on different structural configurations and design scenarios. In particular, it was studied the influence of the location of the removed column on the structural behaviour. The collapse of central, lateral and corner columns were investigated in order to understand the load transfer mechanism, the requirement of joint ductility and the influence of the concrete slab on the development of alternate load paths. Both experimental and numerical results showed that the concrete slab plays a key role on the load transfer mechanism within the structure: it can hence contribute significantly to the robustness of the system preventing progressive collapse. The knowledge of the response of reinforced concrete slabs subjected to large displacements, as in the case of a column loss, allows quantifying the contribution to the resistance of the building to collapse associated with activation of membrane forces. Regarding this aspect, a new analytical simplified method, based on the principle of virtual works, was developed to predict the load-deflection response of simply supported reinforced concrete slabs with planar edge restraints subjected to large displacement. In conclusion, the present work provides a significant contribution to the knowledge of composite steel-concrete structures subjected to extreme loading conditions and open the way to extend results to different structural configurations and loading scenarious.

Notches, wedges, cracks, sti?eners, inclusions and defects in plane elastostatics are known to generate singular stresses and limit the overall strength of a composite material. In the present thesis, after showing experimentally that the singular stress ?eld predicted by the linear elastic solution for the rigid inclusion model can be generated in reality and with great accuracy within a material, attention is devoted then in achieving the out-of-plane response of an in?nite plane containing polygonal and hypocycloidal-shaped voids and rigid inclusions subject to generalized remote loading conditions. The analytical solution obtained for the case of polygonal inclusions shows some unexpected and interesting features such as an in?nite set of geometries and loading conditions exist for which not only the singularity is absent, but the stress vanishes (annihilates) at the corners. Thus the material, which even without the inclusion corners would have a ?nite stress, remains unstressed at these points in spite of the applied remote load. Moreover, similar conditions are determined in which a star-shaped crack or sti?ener leaves the ambient stress completely unperturbed, thus reaching a condition of ‘quasi-static invisibility’. The solution in closed-form is also obtained for the case of hypocycloidalshaped voids and rigid inclusions, showing that cusps may in certain conditions act as stress reducers, situations for which the stress at the cusp tip in the presence of the inclusion is smaller than in the case when the inclusion is absent. Ph.D. Thesis – Summer Shahzad vThe obtained solutions provide closed-form expressions for Stress Intensity Factors and Notch Stress Intensity Factors at varying the inclusion geometry and of loading conditions, fundamental quantities in de?ning criteria of fracture initiation/propagation or inclusion detachment. The ?ndings of stress annihilation, stress reduction and inclusion invisibility de?ne optimal loading modes for the overall strength of a composite and are useful in the design of ultra-resistant materials.

“[…]Landscape” means an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors; […]Acknowledging that the landscape is an important part of the quality of life for people everywhere: in urban areas and in the countryside, in degraded areas as well as in areas of high quality, in areas recognised as being of outstanding beauty as well as everyday areas[…]”. The starting point of this research is the innovative definition of landscape, given by the “European Landscape Convention”, that draws the attention to the need of: - examining the territory as a spatial and temporal continuity; - considering the territory transformations as a value; - giving equal dignity to ruined territory, refusing the idea that only beautiful landscape deserve to be protected. Among the several and diverse European studies on infrastructure and landscape relation, the research focuses on marginal areas created by the infrastructure for mobility (road and highway) in the landscape. These areas are lacking a clearly defined function, they are not anymore part of the landscape, but they have not become part of the infrastructure. These areas are defined as infrastructural refuses. The attention is shifted from the design of the road and from the aesthetic of mobility to the new spaces created by the infrastructure in the landscape. Moreover, the research tries to analyze the infrastructural refuses only ex-post, when these spaces have already been created by the construction and use of a road, or theoretically created in-fieri by an infrastructure project that has overlooked these areas, forgetting to design them, or simply not taking into account their existence. The first part of the research is devoted to define the identity of the infrastructural refuse through the critical analysis of the main theories of the protagonists of the international debate supported by the identification of literature related to the topic. The infrastructural refuse is then described through analytical tools (morphology and perception) that show the effects of infrastructural transformation focussing mainly on mobility infrastructure transformation in Trentino Alto-Adige. The case study analyzed is the trunk road 12 on the stretch called Tangenziale di Trento, and more specifically the transformation caused by the junctions close to urban areas. The Tangenziale is a great artery of traffic that often cuts through the surrounding areas leading to real marginal areas. The research then proceeds to the definition of refuse as a value and tries to highlight its potential for transformation mainly by analyzing the strategy of recycling. Different types of re-use of infrastructural refuses are described: the artistic-temporary use, the daily spontaneous use by the population, and finally the illegal use. The research analyzes the mobility infrastructural refuses: outlining possible transformations, design, re-inventions; illustrating the unexpressed features of the places; re-drawing with different connotation signs that have lost their original meaning; eventually reaching the “operatività dello scarto”. Negative actions like abandon, refuse, waste can become occasions to re-shape and re-think the landscape. The results of the research show the possibility to re-think the infrastructural refuse spaces as a reserves of soil, suggest alternatives to the mentality of the compensation and mitigation, calling for the evolution of the protocols of mobility infrastructure design.

The fate of reactive solutes in groundwater is largely determined by mixing, since dilution and reactions are controlled by mixing rates. By mixing we refer to the overlap of solute bodies with a different composition, which makes possible the encounter between reacting molecules. Therefore the quantification of mixing has an important role in contamination and risk assessment and remediation technology, when they rely on processes of natural attenuation, biodegradation or chemical delivery. As porous formations are ubiquitously heterogeneous, and heterogeneity features, besides being deterministically unknown, belong to a hierarchy of scales, the description of transport processes has to deal with two main issues: epistemic uncertainty and reference scale. While the heterogeneous nature of porous media interferes with physical and chemical processes (which are inherently related to the quantification of mixing and mixing-controlled processes), the choice of the reference scale is related to the means of modeling the phenomena. In order to have an accurate representation of mixing at the continuum scale, we develop a few numerical tools, all belonging to the Lagrangian framework, and compare them with classic Eulerian and Eulerian-Lagrangian schemes. Typical transport scenarios are characterized by highly fingered plumes and sharp fringes, and pose several numerical problems (e.g. artificial diffusion and spurious oscillations). In particular, artificial diffusion can in some cases overcome the actual local dispersion, thereby possibly determining gross overestimations of reaction rates. Our numerical tests provide a set of guidelines for a conscious choice of the numerical scheme according to the objectives of the investigation and to the heterogeneity level, highlighting the drawbacks of the numerical schemes on both the evaluation of dilution and of the overall effect of reactions. Under the assumption of complete mixing at the Darcy scale, we model both instantaneous and kinetically-controlled reactive transport on synthetic bi-dimensional hydraulic conductivity fields in order to investigate the complex interplay among velocity non-uniformities, local dispersion and reaction rates at increasing levels of physical heterogeneity. We also compare the effects of different local dispersion models and injection modes (uniform vs non-uniform), still analyzing the results on a single-realization basis. Realizations share the same log-conductivity structure but are characterized by variances ranging from low (0.2) to high (10). Resorting to single-realization analysis is uncommon in the literature, unless when ergodicity conditions are fulfilled. On the other hand, ensemble analysis is insensitive to local features and does not often offer a reliable representation of actual field phenomena, especially in non-ergodic conditions. Hence single-realization scenarios can be used for understanding the key processes and their interaction, or for grasping aggregated information on the whole solute body behavior. Under simplified conditions, that is, limiting the investigation to low heterogeneity fields, these numerical results are compared to simplified Lagrangian semianalytical relations aiming at reproducing plume-averaged quantities. This Lagrangian theory provides relevant information relying on a limited amount of information, i.e. low-order geostatistical properties of the formation, aquifer's geometry, reactive parameters and problem forcings (e.g. initial and boundary conditions for the flow field and the concentration of the involved species). The match between empirical and theoretical global moments is very good in all tested conditions (two different Peclet numbers, a few heterogeneity levels up to log-transmissivity variance equal to 2 and three different source sizes), and also Beta Cumulative Frequency Distributions (CFDs) with shape parameters obtained by substituting the theoretical global moments compare well with the numerical CFDs. As expected, coherent estimates of peak concentration are not equally good, because of an inherently different nature of this quantity as opposed to plume-scale concentration moments. The a-priori information expressed by statistical analysis both at the global scale and at the local scale for a conservative tracer z can be transferred to reactive species in case of very fast kinetics. Given this useful property of equilibrium reactions, we develop explicit semianalytical relations for the moments and the probability distribution functions of the concentration of chemical species reacting according to a bimolecular equilibrium homogeneous reaction. We assume that the conservative tracer probability distribution function, both at the local scale and at the global scale, can be modeled with a Beta distribution, fully characterized by the mean and the variance of z. Rigorous numerical testing on highly heterogeneous velocity fields confirms that this assumption holds. A few illustrative cases shed some light on the role of the reaction on the time evolution of (local and global) concentration for the different reactive species, and on the different quality of information contained in local statistics as opposed to global statistics. The Beta distribution is a powerful predicting tool for the space and time evolution of passive concentration and, by extension, also for reactive species in particular chemical conditions. Analytical procedures are needed for predicting the z moments, as for example the Lagrangian ones used in the present work, which are limited to weakly heterogeneous formations. Finally we explore, analytically and numerically, the upscaling from the pore scale to the Darcy scale. Via multiple scale analysis we identify a homogenizability region, in terms of the dimensionless numbers regulating a multicomponent precipitation/dissolution reactive problem, where Darcy-scale (upscaled) transport equations can be used, regardless of sub-Darcy scale inhomogeneities.

This doctoral thesis focuses on the seismic risk mitigation of â special riskâ industrial facilities, like chemical, petrochemical and process industries. It is known that the impact of natural hazards, such as earthquakes, on this type of structures may cause significant accidents leading to severe consequences to both the environment and human lives; see, among others, Lanzano et al., (2015) and Krausmann et. al (2010). In particular, the most critical components in a petrochemical plant are fluid-filled storage tanks; they can experience severe damages and trigger cascading effects in neighbouring tanks due to large vibrations induced by strong earthquakes, indeed. In order to reduce these tank vibrations, an innovative type of foundation based on metamaterial concepts is investigated. Metamaterials are generally regarded as manmade structures that exhibit unusual responses not readily observed in natural materials. Due to their exceptional properties and advancements in recent years, metamaterials have entered the field of seismic engineering, and therefore, offer a novel approach to design seismic shields. As a result, an encouraging and practicable strategy for the seismic protection of liquid storage tanks is presented and validated. On the other hand, the outcomes of this research study also aim to improve seismic risk assessment of â special riskâ facilities mainly through experimental dynamic analysis. In view of performing a dynamic analysis of these complex components, necessary for the global seismic risk assessment procedure, online hybrid (numerical/physical) dynamic substructuring simulations have shown their potential in enabling realistic dynamic analysis of almost any type of nonlinear structural system. At the same time, owing to faster and more accurate testing equipment, a number of different offline experimental substructuring methods, operating both in time and frequency domains, have been employed in mechanical engineering to examine dynamic substructure coupling. The scope of the study is the exploitation of different Experimental Dynamic Substructuring (EDS) methods in a complementary way to expedite a hybrid experiment/numerical simulation and, consequently, the comprehensive dynamic analysis. From this perspective, after a comparative uncertainty propagation analysis of three EDS algorithms, a new Composite-EDS (C-EDS) method is proposed and numerically validated. To the best of the authorâ s knowledge, this research study presents the first algorithm used to fuse both online and offline algorithms into a unique simulator with significant advantages in terms of dynamic analysis and seismic risk assessment of industrial plants. Finally, the research activity is supported by the results from different experimental testing campaigns with the main purpose to investigate the complex behaviour of critical industrial components, such as Tee joints and Bolted Flanged Joints (BFJs), with particular regard to the leakage phenomena resistance. In this respect, a reliable an innovative model capable of predicting the leakage force for a generic BFJ, including the interaction between axial and shear load, is proposed and validated.

This research has started from some issues affecting the debate in progress on policies for landscape and confronts itself with the actuality of a review of some paradigms of interpretation that could substantiate the practice of landscape transformation. The main questions that will be addressed is what the ordinary contemporary landscape is, experimenting the perception as a tool at first of interpretation, therefore potentially operating, from the demands of the European Landscape Convention, according to which “Landscape means an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors†. Assuming the landscape perception as a means of expression of the relationship between society and territory, this study develops and tests a methodology for its comprehension, through kaleidoscopic visions which interpret the variety of the situated looks. By means of the methodology we aim to explore how a variety of people experience landscapes and – as a consequence - how they perceive them. The proposed approach refers to the landscape perception as a complex system in its multiple dimensions (physical/natural, symbolic/cultural, personal/ collective) that becomes significant as expression of a contemporary condition of living places. It begets a thinking material to understand values and themes, on which could be possible basing actions and policies for landscape. The Kaleidoscope, which is here proposed as device to represent perceived landscapes, derives from the sense of this research. Actually, the explicit reference to ordinary landscapes implies the awareness that the contemporary landscape can not be understood through a tale made of synthetic and mimetic/typological representations, but is expressed predominantly in ordinary contexts, whose not consolidated images neither shared attributions of meanings exist. The Kaleidoscope has set as a composition of diagrams and narratives, which are translated in looks type and themes for action, contributing to reify the problems the landscape poses as challenges to planning and the perception is offering to return. The research is substantiated by a long experimental stage, when - through an experience of understanding the perceived landscape in a valley place in Trentino - the themes tackled in the theoretical-critical part pit themselves strength the realm of a contemporary landscapes and the specificity of the ordinary ones, which more than others claim the experimentation of interpretative and operational tools. The experience has been set up as a cognitive practice, able to be consolidated and repeatable in the ordinary planning processes. It can therefore be understood as a paradigmatic experience of approach to contemporary landscape.

Conventional Activated Sludge (CAS) systems have been widely implemented to treat wastewater. CAS systems produce huge amounts of waste sludge and its subsequent treatment represents up to 65 % of the operational costs of Waste Water Treatment Plants. The final disposal of sludge is usually performed by landfilling or incineration, involving severe environmental issues. In order to reduce sludge amount, many studies have been conducted, developing new technologies. One of these technologies is HydroThermal Carbonisation (HTC), where sludge is heated up to 180-250 °C at water vapour pressure producing a solid product enriched in carbon for different possible exploitations. The aim of this work is to apply HTC to different kinds of sludge such as thickened sludge, digested sludge and dewatered sludge and compare the behaviour of the solid and liquid phases produced by the process. For the purpose, experimental tests were performed at different operating conditions in a lab batch reactor capable to withstand high pressure (140 bar) and temperature (300 °C). In order to compare the HTC products of the different kinds of sludge, the hydrochars from HTC at different operative conditions were characterized in order to explore possible application of hydrochar and HTC process water.

With the advantages of CFST built-up columns, including the higher confinement in the concrete, delay of the steel local buckling, higher compressive and flexural strength, earthquake and fire resistance, rapid construction, savings in the construction costs, etc. CFST built-up columns are increasing adopted in structural members with larger load eccentricity ratio and slenderness ratio, such as stadium, industrial buildings, bridge pier and pillar, and electrical transmission tower. However, the research is mainly focused on static performance, seldom research has been reported on the dynamic behavior of CFST built-up columns. The present research investigates the seismic behavior of CFST built-up columns. A detailed literature survey on the CFST built-up structures, including mechanical characteristics, applications, ductility in seismic design, previous experimental researches, and finite element formulation, is firstly illustrated. Six specimens with different grades of concrete and brace arrangements are designed and tested subjected to cyclic loading. The hysteretic behavior, such as failure mode, deformed shape, displacement ductility, rigidity and strength degradation, and energy dissipation capacity of test specimens are discussed. The corresponding validated finite element model (FEM) simulations are developed for parametric analysis, to discuss the hysteretic behavior, affected by axial load ratio, chord spacing, brace spacing, diameter to thickness ratio, and steel yield strength. Results indicate that the hysteretic characteristics of specimens are saturated and exhibited good ductility. The concrete strength and steel yield strength played a slight effect to the displacement ductility factor. While the ductility will be significantly affected by axial load ratio and geometrical types. Based on extended parametric analysis and regression analysis, a simplified method, consisted by equivalent slenderness ratio, axial load ratio and steel yield strength, is proposed to calculate the displacement ductility factor of CFST battened columns and laced columns, respectively. The accuracy is validated with test results. After that, to investigate the seismic performance of built-up columns used in practice, an innovative lightweight bridge with CFST composite truss girder and CFST lattice pier is studied as case study. For the purpose, FEM simulation and shaking table test are carried out. The FEM results agree with experimental data. In addition, the plastic hinges were predicted under transverse and longitudinal excitation respectively, revealed that CFST built-up columns has a favorable seismic performance.