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.

Protection of high-value building contents from seismic damage represents a worldwide challenging task. Artefacts, sophisticated medical and electrical equipment, high performance computer installations and other special contents have shown, in the last years, their high vulnerability both for high and moderate earthquakes. The lack of effective techniques, sufficiently developed for seismic risk mitigation of such objects, makes the seismic protection of contents a crucial issue. An effective means to provide this protection is seismic isolation. The isolation techniques to be used for the content are not a mere extension of the ones used for civil structures, although the basic theories and concepts of seismic isolation are the same. Indeed, the following technical peculiarities have to be considered: the contents have masses orders of magnitude smaller than those characteristic of civil structures and, secondly, they are often very vulnerable and are not able to withstand even small seismic actions. This thesis, that fits into this context, presents an innovative seismic isolation device for lightweight structures, named “RBRL” system, i.e. “Rolling-Ball Rubber-Layer”, and it is aimed at studying the dynamic behaviour of the system itself through numerical analyses and parametric experimentations, with the goals to get a sufficient comprehension of the system performance and its general numerical characterization. The device, invented by Alan Thomas at TARRC (“Tun Abdul Razach Research Centre”) comprises: a rolling-based bearing system, which allows any displacements in the horizontal plane; two rubber layers bonded to the steel tracks, which give an adequate damping to the rolling steel balls; some rubber springs, which ensure the recentering of the system through their elastic stiffness.

In this work, aspects concerning the behaviour of steel joints under combined actions are investigated. Adopting the philosophy of the component method the attention focused on the analysis of a basic component of the connection: the T-stub. Research works carried out in the recent past extensively investigated the T-stub response under tension, while no data are available for the T-stub's response under combined tension (N) and shear force (V). In the thesis experimental, numerical and theoretical studies on this topic are presented. The starting point is the experimental activity carried out at University of Trento on column T-stubs under different combinations of axial and shear force. The experimental outcomes strongly highlighted the influence of the loading conditions on the strength and deformation capacity of the T-stub. In a second phase 3D numerical models were developed and calibrated to reproduce the actual behaviour of the T-stubs. The numerical simulations were then extended to different specimen geometries to investigate the main geometrical parameters which could affect the T-stub response. On the basis of experimental and numerical data a theoretical model based on limit analysis was then developed. It allows predicting a simplified load-displacement curve of the T-stub under a generic combination of N and V. The results obtained from the analytical model seem to reproduce with sufficient accuracy the complex behaviour of the T-stub, allowing to appraise the elastic stiffness and the yield load.

The research activity is focused on the study of both the linear and nonlinear behaviour of light timber-frame shear-walls buildings (called Platform Frame); in the first part the analysis of the linear-elastic behaviour is presented, whereas in the second part the non-linear behaviour is considered. After a short introduction on the state of the art of timber buildings both from the constructive and from the legislative point of view, the linear-elastic behaviour of single timber shear-wall is presented. The analysis of a single timber shear-wall allows to develop an analytical equation and simplified numerical macro-model (called UniTn-Model) which are able to represent the behaviour of a wall both in terms of displacement capacity and, much more important, in terms of stiffness. In fact, the evaluation of the correct walls stiffness constitutes a fundamental step in the seismic analysis of the timber buildings. The later section is based on what stated about the single-wall and it deals firstly with the elastic behaviour of systems composed by single-storey coupled walls and then it analyses systems of multi-storey single-walls. Theses analyses highlighted the influence of the vertical loads on the external force distribution within the shear walls, as well as the changing of the system stiffness caused by the hold-downs state variation. Both these aspects allow to develop some analytical formulations through which the stiffness matrix of full-scale buildings can be determined. Three iterative methods for the application of the Modal Response Spectrum Analysis are also presented; the differences between the methods, from the computational point of view as well as from the analytical one, are emphasized by means of a case study. The second part illustrates the non-linear analysis of a single shear-wall in order to identify the influence of the base components features on the wall ductility, both from the qualitative and the quantitative point of view; the UniTn-Model is hence extended to the non-linear field. It is also determined that the contribution of the nail deformation is not dependent on the nails spacing but it is only dependent on the geometry ratio of the sheathing-panels themselves. This property, analytically determined, is demonstrated on the basis of numerical and experimental analyses, by means of some non-linear F.E.M. analysis and some ad-hoc laboratory tests respectively. In the following section, using what developed for the single shear-wall, the non-linear analysis of single and multi-storey full-scale buildings is performed. The analyses are performed in order to assess the ductility level achievable by the buildings varying the ductility of the base components as well as the failure mechanism. In order to get generalized results and provide reliable values of ductility for the constructive system analysed, a large set of non-linear analysis has been performed through the use of a Matlab code specifically developed. This allowed to determine the ductility level that light timber-frame buildings can reach and to propose a new set of values for the behaviour factor q to be used in the seismic design. In the last section the study of the applicability of the capacity design to the light timber-frame buildings is presented. This study assesses the conditions that make the capacity design physically feasible and economically viable in comparison to the elastic design. The analyses have been conducted by varying both the geometry of the buildings that the seismic force level.