The research is aimed at developing seismic methods for the design and evaluation of the seismic vulnerability of wooden structures, using a displacement-based approach. After a brief introduction on the seismic behaviour of timber structures, the general Direct Displacement-Based Design (Direct-DBD) procedure and the state-of-the-art are presented, with clear reference to the application of the Direct-DBD method to wooden buildings. The strength of the Direct-DBD method is its ability to design structures in a manner consistent with the level of damage expected, by directly relating the response and the expected performance of the structure. The research begins with a description of the procedural aspects of the Direct-DBD method and the parameters required for its application. The research presented focuses on the formulation of a displacement-based seismic design procedure, applicable to one-storey wooden structures made with a portal system. This typology is very common in Europe and particularly in Italy. A series of analytical expressions have been developed to calculate design parameters. The required analytical Direct-DBD parameters are implemented based on the mechanical behaviour of the connections, made with metal dowel-type fasteners. The calibration and subsequent validation of design parameters use a Monte Carlo numerical simulation and outcomes obtained by tests in full-scale. After the description of the Displacement-Based method for one-storey wooden structures, a series of guidelines to extend the Direct-DBD methodology to other types and categories of timber systems are proposed. The thesis presents the case of a multi-storey wood frame construction, which is a simple extension of the glulam portal frame system. Part of this work has been done within the RELUIS Project, (REte dei Laboratori Universitari di Ingegneria Sismica), Research Line IV, which in the years between 2005 and 2008 involved several Italian universities and Italian institutes of research in the development of new seismic design methods. The Project produced the first draft of model code for the seismic design of structures based on displacement (Direct-DBD). This thesis is the background to the section of the model code developed for timber structures.

Seismic testing methodologies play a significant role in earthquake engineering due to complexities of engineering materials and ground motion. Among available testing methods, hybrid simulation is more appealing for its merits, e.g., evaluating dynamic responses of large scale structures at lower cost. As a novel member of hybrid simulation, Real-time Hybrid Simulations (RHS), since its conception in 1992, has shown its unique properties and capacity for testing complex structural components, especially rate-dependent ones. RHS often partitions the emulated structure into portions, which are then either numerically or physically simulated in real-time according to our knowledge of them. In particular, the critical nonlinear and/or rate-dependent parts are often physically modelled within a realistic real-time test, while the remainder parts are simultaneously evaluated by solving differential equations. Evidently, the challenge of these methods is to enforce the coupling at the interface between portions via real-time loading and real-time computation. Heretofore great development of RHS has been attained. This dissertation is devoted to developing RHS in two aspects, namely transfer system control and time integration algorithms. In detail, research work and findings are summarized as follows: The dissertation initially focuses on the implementation of a model-based control strategy –internal model control (IMC) and its comparison with the classic PID/PI control on the lately conceived high performance test system - the TT1 test system. The control strategy of the electromagnetic actuators consists of three loops, namely one speed loop and two displacement loops. The outer displacement loop is regulated with IMC or PID/PI whilst the inner two loops with proportional control. In order to compare different control strategies, realistic tests with swept sinusoidal waves and numerical simulations concentrating on robustness were carried out. Analysis showed that IMC is preferable for its robustness and its ease of implementation and online tuning. Both IMC and PID work similarly and well on the actuator which can be simplified into a first-order system plus dead time. In addition, RHS was performed and showed the favorable state of the system. In order to accurately compensate for a time-varying delay in RHS, online delay estimation methods were proposed and discussed based on a simplified actuator model. The model, consisting of a static gain and dead time, results in nonlinear relationships among different displacements. The estimation based on the Taylor series expansion was further developed by introducing the recursive least square algorithm with a forgetting factor. Then this scheme was investigated and assessed in pure simulations and RHS via comparison with two other methods. Finally, the proposed scheme was identified to be satisfactory in terms of its convergence speed, accuracy and repeatability and to be superior to other methods. With the insight into the weakness of available compensation schemes in mind, two polynomial delay compensation formulae considering the latest displacement and velocity targets were proposed. Assessment and comparisons of the formulae by means of frequency response functions and stability analysis were carried out. In order to facilitate delay compensation, another novel compensation scheme characterized by overcompensation and optimal feedback was conceived. Numerical simulations and realistic RHS were performed to examine the proposed schemes. The analysis revealed that the proposed polynomial formulae exhibit smaller prediction errors and the second-order scheme with the LSRT2 algorithm is endowed with a somewhat larger stability range. Moreover, the overcompensation scheme was concluded to have the ability of time-varying delay accommodation, error reduction and sometimes stability improvement. With regard to time integration algorithms, this dissertation extends the equivalent force control (EFC) method which is a method of RHS with implicit integrators to RHS on split mass systems. The EFC method for this problem was spectrally analyzed and was found more satisfactory stability than some explicit integrator. Then larger control errors due to quadartically interpolated EF commands were recognized and treated with a proposed displacement correction. In view of the inherent feature of RHS –multiple quantities coupling at the interface, the correction was extended to simultaneously update displacement and acceleration. Spectral stability analysis and numerical simulations demonstrated that: (1) the correction can remove the constraint of zero-stability to the method and reduce algorithmic dissipation; (2) it also works well for MDOF systems. Finally, an inter-field parallel algorithm for RHS, namely IPLSRT2, was developed and analyzed. This method was based on the Rosenbrock (LSRT2) method and a prior inter-field parallel integrator–PLSRT2. The LSRT2 with different stage sizes, velocity projection and modified Jacobian evaluation were introduced to the algorithm in order to avoid and/or weaken the disadvantages of the PLSRT2 method, such as inefficient computation, displacement and velocity drifts, and complicated starting procedure. Accuracy analysis, spectral stability analysis, pure numerical simulations and realistic RHS were performed to investigate the properties of the IPLSRT2 method. Compared with the PLSRT2 method, this method exhibits pros and cons. In detail, the method loses the accuracy order due to the velocity projection applied at all time steps. However, it can provide more accurate displacement and velocity results in common applications where a little larger time step is required. In some cases, the proposed method exhibits smaller phase shifts and dissipation. Moreover, computation efficiency in Subdomain A is improved and its implementation in real-time applications is simplified.

Most of the significant changes on the environment have resulted from individually minor but collectively significant human actions and decisions. This kind of consequences has been defined Cumulative Effects (CE) and their systematic consideration can be attributed to the scientific basis and institutional context of Environmental Assessment (EA) theory and practice. However, although Strategic Environmental Assessment (SEA) has been largely recognised as one of the most appropriate procedure to support spatial and land use plans in managing CE; the advancement in integrating the assessment of CE into SEA practice has been often stated slow to evolve, suggesting a gap between SEA theory and practice in treating cumulative effects and confirming that further investigation on this subject is required. This research aimed to propose and apply a methodological approach to improve the consideration of CE in SEA of spatial plans, by focusing on the Italian spatial planning system and urban regions. It was developed according to the main findings and shortcomings emerging from the academic literature and the exploration of SEA practice through: an international expert survey; a systematic review of SEA documents; and a couple of real-life SEA case studies following during the research period. Among the most important were: the lack of scoping of relevant resources (or Valued Ecosystem Component); the scarce exploration of future decisions and consequences; and the requirement of a more evidence-based assessment of CE. The methodological approach was then developed for SEA of regional spatial plans, consisting of four main tasks: the selection of significant valued resources; the identification of other relevant decisions (projects, plans and policies) which together with the spatial plan could contribute to CE; the generation of land use scenarios; and the prediction of CE through indicators. Then, the methodological approach was tested in a case study selected within the peri-urban region of Milan, representing one of the most urbanised and industrialised part of Italy, with significant urban pressures on existing protected areas and remaining rural patches. Firstly, the regional green infrastructure was selected as the most important regional valued resource (or VEC); then, three important ‘future policies’ were identified (i.e. highway transportation corridor, protected areas conservation plans, and rural policies). Subsequently, a set of future land use scenarios were developed and made spatially explicit, starting from a couple of regional land use maps. Then, the regional cumulative effects on the selected valued resource (e.g. habitat fragmentation, surface runoff, etc.) were assessed against a range of future conditions through a core set of indicators, mainly quantitative and spatially explicit, simulating relevant environmental processes, such as hydrological cycle, local surface temperature, ecological connectivity. They were all selected and computed starting from land cover data, allowing the combined effects to be quantified and land use scenarios to be compared. The results mainly showed that the method provided an applicable means to, firstly, transfer policies and decisions into maps, and then, predict their combined effects on selected VEC. Moreover, it can be straightforwardly included in SEA of regional spatial plans in order to support a more evidence-based CE analysis, by adding spatial thinking to decision-makers and improving the understanding and the perception of the cumulative consequences of their “minor” decisions under uncertain future policy contexts.

Bridges in service in most Western Countries were built according to codes with design loads that are now inconsistent with today’s traffic demands. Currently, transportation agencies do not know how to respond to transit applications on their bridges. This thesis focuses on the legal issues entailed by overweight/oversize load permits issued by transportation agencies. Indeed, correct decision-making should consider the legal liabilities involved in possible catastrophic events. In this thesis I illustrate how this problem is guided by the Department of Transportation of the Italian Autonomous Province of Trento (APT’s DoT), a medium-sized agency managing approximately one thousand bridges across its territory. In the basic approach, it does not authorize movement of overweight loads unless it is demonstrated that their effect is less than that of the nominal design load. When this condition is not satisfied, a formal evaluation is carried out in an attempt to assess a higher load rating for the bridge. If, after the reassessment, the rating is still insufficient, the bridge is classified as sub-standard and a formal evaluation of the operational risk is performed to define a priority ranking for future reinforcement or replacement.

This study concerns seismic vulnerability assessment of masonry arch bridges with common typologies in Europe. Bridges are, in most cases, the most vulnerable elements in the transportation network during an earthquake; therefore, their seismic vulnerability assessment is necessary for a proper planning of the emergency phase and to define a priority for retrofit interventions. Masonry arch bridges were subdivided into homogeneous classes of single span and multi-span structures, according to the result of a statistical analysis made up of a large stock of 757 railway bridges located in high seismic areas. All the different collapse mechanisms for seismic action were studied for each class of masonry arch bridges with application of limit analysis and the calibration with FEM. In particular, limit analysis methods for the seismic assessment of single and multi spans bridges were developed. A innovative limit analysis approach was proposed for the assessment of the global transverse seismic capacity of multi-span masonry bridges with slender piers. Envelope curves representing the seismic capacity expressed in terms of limit horizontal acceleration were derived by parametrical analysis by means of simplified limit analysis. These curves can be used for a simplified vulnerability assessment of masonry arch bridges and for a simple calibration of the judgment obtained by BMS through inspection visits to bridges. In the second part of the study, a new simplified approach for the fast calculation of seismic fragility curves of numerous masonry arch bridge clusters is proposed. The aim of this thesis is to propose a quickly procedure to estimate the seismic vulnerability of extended roadway and railway bridge networks in emergency conditions and to optimize the retrofit interventions.

This thesis explores the concept of equity and proposes methods to make it operational in decision-making focused on promoting sustainability. The conceptual approach developed in the research draws on the recognition that the two notions of equity and sustainability are tightly intertwined in the sustainable development debate. As George (1999) claimed, sustainable development is founded on and fully embodied by intra-generational and inter-generational equity, which might be described as transactions of rights between and across generations, respectively. In spite of this, the implications on equity are still poorly addressed in strategic decisions. This led to the identification of the three main objectives of this research. The first objective is to understand the extent to which sustainability issues are addressed in current practice, focusing on Strategic Environmental Assessment (SEA) experiences of spatial planning and Oil & Gas development. To this purpose, a framework is developed to analyse the degree of consideration of sustainability principles in SEA, and demonstrate its application to a sample of SEA of Italian urban plans. This framework links Gibson's (2006) sustainability principles to a number of guidance criteria and eventually to review questions, giving particular emphasis to the key concepts of intra- and inter-generational equity. The framework was applied to review the Environmental Report of a sample of urban plans of major Italian cities. The results of this review shows that, even if sustainability is commonly considered as a pivotal concept, there is still work to be done in order to effectively integrate sustainability principles into SEA. Regarding the proposed framework, the review confirms the significance of clarifying equity concerns in the light of sustainability in view of operationalizing intra- and inter-generational equity in decision-making. The second objective is to identify criteria and indicators to measure intra- and inter-generational equity, against which present state and future trends can be assessed. A conceptual framework for identifying the different implications related to the use of different values and perceptions on equity is built. Subsequently, a set of equity perspectives to guide the assessment of strategic actions through the lens of intra- and inter-generational equity is proposed and discussed. This set includes four equity perspectives, compatible with each other with covered significant sustainability issues, and minimizing conflict, namely opportunity, distributional fairness, distributional fairness across generations and justice for an imperfect world. The review of equity perspectives allows identifying a set of equity criteria that might be useful in focusing assessment on crucial and integrative sustainability issues. These criteria are reasonably inclusive of essential general intra- and inter-generational equity considerations that account for sustainability over space and time. However, criteria need to be specific to the context of analysis. This is addressed in this study by selecting a specific sector of investigation that offered significant insights for dealing with sustainability in decision-making. The attention was directed to the Oil & Gas sector for the scope of challenges and positive chances posed to sustainability. For this purpose, the research work specifically fleshes out how current SEA of Oil & Gas sector practice addresses sustainability. A framework for reviewing SEA practice helped to explore to what extent current SEA for the Oil & Gas sector contributes, procedurally and substantively, to sustainability oriented decisions. 11 case studies related to both off-shore and on-shore Oil & Gas developments are reviewed against this framework. The results show that case studies were more oriented to analyse opportunities derived from Oil & Gas development without fleshing out other potential developmental alternatives. Additionally, even if the SEA reports claim to pursuit a common strategic intent to equally share benefit derived from Oil & Gas development, they do not generally provide a means to tackle this aspect. This part of the investigation allowed also to support the identification and selection of aspects, elements, suggestions and best practise that would assist in defining contest-specific equity criteria and indicators for decision-making in the Oil & Gas sector. This leads to the third objective of the thesis: testing the applicability of the proposed methods to a case study, dealing with complex decisions at strategic level. A case study on Oil & Gas development in the Basilicata region (Southern Italy) was selected: the Val d’Agri oil field, Western Europe’s biggest onshore oil field. Scenario storylines, representing interactions among environmental, social and economic concerns, are constructed and applied against the framework. Specifically, short-term and medium-long term scenarios are developed by varying geographical scopes, ranging from the regional scale to two nested local areas surrounding the Oil & Gas activities. Scenarios are then assessed against the set of intra- and inter-generational criteria identified by selecting appropriate indicators adapted to context and available data. Indicators are valued according to a quali-quantitative analysis that assisted in examining and comparing trade-off between human and environmental systems under the different scenarios. The results helped to identify opportunity and risk of different scenarios at strategic level. None of the scenarios provided “the best solution†in term of aggregated equity scores or perfect win-win solutions for each equity perspective. In the long-term, none of the territorial levels (local and regional) seemed to acquire significant increase in equity benefits, not even one at expenses of each other. According to the assumptions, this might suggest that incremental benefits of Oil & Gas development are concentrated outside the three level considered. Nevertheless, the case study shows that approaching to decision with more attention to a sustainable management of the environment and involving institutions at different levels might be a key role in achieving more wide-spread and long-term positive results. However, scenarios presented possible significant trends in equity criteria, which were affected by restraints in data collected, as well as, simplifications and approximations in analysis. In this exercise, it was assumed that all equity criteria within each temporal dimension receive equal weights and that all three geographical levels were equally weighted too. Introducing participatory mechanisms might be useful for supporting interpretations of implications potentially affecting generations at different temporal and territorial scale, satisfying possible needs of other equity criteria, and establishing priorities in perspectives on equity adopted. In this sense, the equity framework proposed might be a suitable tool for supporting and guiding deliberative processes. Analogously, the spatio-temporal decision matrix, framed through the lens of equity for assessing scenarios against equity criteria, might represent a simple yet flexible framework for analysing and discussing concurrently temporal and spatial implications of plausible storylines.

Structural Health Monitoring is an important aspect in civil engineering, dedicated to monitor and maintain the structural conditions of civil architecture objects. It results in extension of their life time and appropriateness for human use. Present, commercially available sensors for SHM are complex, sophisticated and multicomponent systems. Although, they provide high precision of measurements, their total cost (the price and costs of exploitation) has been still too high to be commonly applicable. There are also other disadvantages such as distributed architecture, heavy cables or their sensitivity to electromagnetic interference like it is in case of conventional electrical sensors. Unlike them, more advance fiber optic sensors are robust to external fields. However, they involve the infrared light for data transmission, therefore they desire additional support of other devices for data processing. Now a day, there is a lack of portable sensing instruments supporting more sophisticated technologies, whose applications can be reduced by failure assessing with those instruments. Current investigations have been focused on development of structures that can be used as an independent sensing tool without a power supplier, such as mechanochromic photonic crystals with three-dimensional structure. Their mechanochromic properties are visible with naked eye as a color variation on their top surface stimulated by mechanical deformation of the structure. However, their fabrication desires high precision to obtain sample with the high sensitivity to stretching and omit some limitation corresponding to its composition (deeply described in chapter 4). Hence, there is need to find alternative solutions. One of them refers to two-dimensional photonic crystals, which were intensively investigated as a components of sensing systems such as MOEMSs (micro-opto-electro-mechanical microsystems). However, their main disadvantage is the fabrication that involves the lithography techniques, which are quiet expensive and time-consuming. Furthermore, the lithographic techniques desire clean room conditions. Hence, the number of produced specimens is limited. In this thesis, there is proposed completely new approach to develop a strain sensor, including fabrication of strain-sensitive sample and methodology of measurements. The sample was fabricated as two-dimensional finite structure of hexagonally arranged voids on the PDMS substrate. The applied fabrication protocol was cost-effective and not time-consuming. The final product was a PDMS replica of monolayer colloidal crystal obtained by self-assembly of polystyrene colloidal spheres. Further investigations involved diffractive properties of its periodic structure. Its strain sensitivity was investigated by monitoring the parameters of diffracted (transmitted or reflected) light such as the diffracted wavelength (chapter 6) and the polarization (chapters 7 and 8), which vary by stretching the sample. Moreover, there was tested another approach, which involved shape changes in diffraction pattern. The diffraction pattern is a result of interaction between a periodic structure and an illuminating light. The obtained data confirmed strong relationship between optical response and the geometry of diffractive structure. However, the experiments require further optimization of fabrication protocol, methodology (conditions of measurements, sample parameters, an appropriate arrangement of components in the experimental setups)

The masonry still one of the widespread construction system for low-rise residential buildings even for countries prone to seismic risk. Despite seismic design methods yet in use are force-based, in the last decades was highlighted as the differences in strength between two levels of damage is low, and therefore as the damage is better correlated to the displacement. Also, in recent years, has arose a widespread expectation for being able to control the damage based on the probability of occurrence of an earthquake or being able to base the design on different performance levels ("performance-based design"). In this context, considerable interest is growing regarding the application of these methods to the design of masonry structures. Many questions are still open and need to be studied more in detail. From the experimental results obtained by cyclic shear-compression tests on different types of masonry panels, an analytical model has been developed, that allows to reproduce the in-plane behavior of both the tested types: one is modern reinforced masonry and the other is traditional multi-leaf stone masonry. The developed model has been used to perform a wide number of dynamic analysis with the aim of studying the inelastic characteristics of the described types of masonry. The results of the analysis made it possible to define simple and reliable formulations for the application of displacement-based method to masonry structures. Finally, we studied the dynamic behavior of a large structure, through the finite element analysis, using a damage model that has been shown to be able to reproduce the response obtained from shaking table tests. This phase has the aims of validate the results obtained for stone masonry walls, and giving useful indication for the application of displacement-based method on multi-degree of freedom structures.

Over the last few years, academic research and international aid organizations have been underlining the important role that the small towns of Sub-Saharan Africa have in promoting development in the surrounding rural areas and in reversing the polarization trend of major urban centers. Nevertheless, defining the particular characteristics of these towns—which the majority of African population lives in or refers to—and analyzing the relevant transformations that they are experiencing are still unsolved issues. Moreover, until now, policies, programs and projects related to African urban development have focused mainly on major urban centers, while small towns have an almost complete lack of planning on how to accommodate people coming from the surrounding rural areas and how to provide them with services. The aim of the research is to define a conceptual and methodological framework to support the spatial planning activity of local administrators and technicians in Mozambique small towns. To reach the objective of a spatial planning process that results from the thorough comprehension of this particular typology of human settlement, the research was based mainly on the analysis of case studies: Caia and Sena, two vilas rurales situated in a rural district in central Mozambique along the Zambezi River. Together with literature review, a field research was conducted by the author in the district of Caia that consisted of the analysis of already existing data and documents, direct observation, interviews with institutional and non-institutional actors, and a household survey in Sena. Afterwards, a SWOT analysis was used as a tool to manage such a greatly varied amount of information. The research process allowed to identify the main features of the small towns, that are here denominated as “rural towns”, and to understand the major trends related to the “rur-urbanization” process. The rural town is defined as a hybrid settlement pattern in which persisting elements of the rural world melt together with emerging urban characteristics. Vilas rurales, in fact, are traditionally rural contexts characterized by a dominance of vernacular settlement patterns and architectures. The socio-economic and cultural features of the towns, as well as their physical structure, are rapidly changing as a consequence of the ongoing “modernization”. The risk is that a rapid and uncontrolled urbanization process could threaten the natural, economic and cultural bases of the small towns without adequately replacing them. Thereby, some suggestions follow on how spatial planning can contribute to the sustainable growth of the rural towns. The central idea that is proposed herein is to preserve the rural characteristics, which are widely present within the rural towns, and to integrate them with the emerging “urban” features. This strategy aims to support the subsistence activities adopted by the majority of the population and to outline a spatial planning process that responds to the specific characteristics of this typology of human settlement by culturally appropriate means. The thesis consists of three parts. The first part presents the results of the literature review. The origin of the debate on small and intermediate urban centers of Third World countries in the late 1970s is presented in Chapter 1 while Chapter 2 actualizes this debate, also in the light of major processes occurring at global level and affecting African small towns. Chapter 3 stresses the big gap in urbanization theory and practices related to small towns of Africa and focuses on their characteristic of being predominantly vernacular settlements in which a “deculturation” process” is taking place as a consequence of the imposition/adoption of western cultural models. The second part of the thesis presents the analysis of case studies. The research methodology is outlined in Chapter 4. In Chapter 5, Caia and Sena are contextualized within their macro-institutional and regional contexts. Then, an analysis of the rural towns is proposed at the local level. Chapter 6 offers a snapshot of the emerging lifestyles in Sena through the results of the household survey. The rur-urbanization process is described in Chapter 7, first by analysing the spatial evolution of Caia and Sena from a historical perspective and, then, by proposing four key topics that identify the main features of the rural towns and describe the major trends related to the rur-urbanization process. The third part of the research, Chapter 8, presents the conclusions. First of all a definition and an assessment of the rural town is offered. Moreover, a conceptual framework is presented that relates key topics, risks, planning principles and actions related to the spatial planning activity in the rural towns. Finally, a methodological framework is proposed that translates the conceptual framework into more operational terms by outlining a spatial planning process aimed at the rural towns.

The assessment and the conservation of historical masonry structures are very challenging issues. According to the actual methodology, all the phases of the entire process of assessment require efforts and reciprocal comparison in order to understand reliably the structural behaviour and to design effective interventions. This thesis goes through such phases (anamnesis, diagnosis and treatment), introducing some innovations in each step and connecting the experimental experiences to models with the support of some real cases. Three techniques are developed about the knowledge phase, namely sonic test, flat jacks and dynamic identification. Deeper studies have been dedicated to vault systems by means of an extended experimental campaign with five full scale vaults tests and a reverse analysis to better understand the behaviour of structures and, at the same time, the limits of models. Sometime this comparison suggests a lack between model parameters and physical meaning due to modelling approaches (mesh, element type) and parameters (material properties and constitutive laws) and this gap may be fulfil by both local and global tests. From the experimental point of view this work presents a wide range of tests from the local to the global behaviour and varying among non-destructive, minor destructive and destructive tests. On the other hand for models, both linear and non-linear approaches have been adopted looking as well to local and global phenomena. Finally, about the deepest analysis on vaults even the scale of modelling was evaluated with the comparison between macro and meso-scale modelling. In this framework some proposal in kinematic analysis of strengthened vaults were provided. The work carried out allows therefore to compare traditional and more used tools for structural assessment purposes with real and measured experiences helping to validate the current methodology in the safety evaluation of existing buildings.