The concept of "integral abutment bridge" has recently become a topic of remarka-ble interest among bridge engineers, not only for newly built bridges but also during refurbishment processes. The system constituted by the substructure and the superstructure can achieve a composite action responding as a single structural unit; the elimination of expansion joint and bearings on the abutments, greatly reduce the construction and maintenance costs. To maximize the benefits from integral abutment bridges, the direct way is to achieve the super-long integral abutment bridge. However, as the environment temperature changes, the lengths of superstructure increase and decrease, pushing the abutment against the approach fill and pulling it away. The responses of bridge superstructure, the abutment, the approach system, the foundation/piles and the foundation soil are all different. And it's important to understand their interactions effective design and satisfactory performance of integral abutment bridges. In order to build longer integral abutment bridges, therefore in this research, the lit-erature survey on the applications of integral abutment bridges in worldwide, espe-cially the current development of super-long integral abutment bridges was carried out firstly. Another literature review on soil-structure interaction was conducted to find out the most suitable methods in considering this kernel issue in design of integral abutment bridge. Through proposing finite element models for integral abutment bridges that could involve the soil-structure interaction, thermal actions, non-linearity in materials and so on, structural study was performed on an existing super-long integral abutment bridge, including parametric analysis, pushover analysis, and dynamic tests. Then, the performance of integral abutment bridge was better understood, and no critical structural problem was found for integral abutment bridge. Based on that, length limit for this kind of bridge was evaluated and investigated in an analytical way. Considering capacities of abutments and piers, and under the conditions of an existing integral abutment bridge, the length limit was found to be around 540m. With this super length, the piles need to be designed with capacity of large lateral displacement. Therefore, an effective optimization approach, associating the finite element method with global optimization algorithm was presented for pile shape design. At the end, considerations accounted in the design of super-long integral abutment bridges were discussed, making construction of super-long integral abutment bridge of great possibility.

Stream ecosystems form an active component of the carbon (C) cycle, and are identified as “hotspots” for carbon dioxide (CO2) emissions. However, the mechanisms driving CO2 emissions from streams are not completely understood. Beside the input of C in the form of CO2 from groundwater, streams receive organic matter from aquatic and terrestrial origins which is partly mineralized to inorganic nutrients and CO2. Future predictions suggest enhanced input of terrestrial organic matter into streams. As such, surrounding land use may highly influence dissolved organic matter (DOM) composition and turnover in streams. The quality, i.e. bioavailability or lability, of aquatic and terrestrial organic matter, as well as which quality feature provides which bioavailability, is controversially discussed and the research is still in its infancy. Thus, the main goal of my thesis is to enhance the understanding of the role of organic matter quality as a potential driver for organic matter turnover in stream ecosystems. A further goal is to shed light on C dynamics with main focus on CO2 of streams surrounded by different land use. The presented work is based on an experimental approach in the laboratory, supported by seasonal field studies and a developed model in order to explore C dynamics and the corresponding drivers in stream ecosystems. The underlying mechanisms and the importance of DOM quality as a main driver was assessed on the small scale in laboratory experiments. The C emissions from streams were quantified and the influence of DOM quality was examined on a stream reach scale by investigating two stream types with different organic matter quality inputs. By developing a process-based model, the understanding of the daily and seasonal scale of C turnover in stream ecosystems was amplified. The results from the experiment under controlled conditions demonstrate that DOM quality governs microbial metabolism (i.e. respiration and bacterial protein production). Moreover, I revealed significant quality differences between two terrestrial DOM sources, while respiration and bacterial protein production increased with the available proportion of the labile DOM source. The molecular weight of DOM was the strongest predictor of bacterial protein production and respiration, while among others, the concentration of low molecular weight substances was another highly influential predictor. The importance of molecular size/weight and DOM quality for microbial metabolism was further confirmed on the stream reach scale where we demonstrated among others a significant linkage between molecular size of DOM and pCO2 across agricultural and forest streams. Moreover, agricultural streams contained significantly higher pCO2 compared to forest streams during all seasons. However, CO2 emissions measured with the powerful drifting chamber method were not significantly different between the stream types. Modeled dissolved oxygen (O2) and CO2 dynamics calibrated with field data resulted in respiratory quotients (RQ = mole of CO2 produced per mole of O2 consumed), which are intimately linked to the elemental composition of the respired compounds across four seasons and two stream types. RQ values were not related to adjacent land use or season. Nevertheless, I found significant relationships between RQ values and DOM quality indicators, such as fluorescing component characteristic for higher plant material and molecule size of DOM in agricultural streams. In conclusion, this thesis demonstrates that DOM quality is an important driver for organic matter turnover in streams. Consequently, my results indicate that ongoing and future land use change and enhanced terrestrial DOM input into streams may influence CO2 emissions, and underline the status of streams as C turnover “hotspots”. Thus, my thesis contributes to the mechanistic understanding of organic matter cycling in stream ecosystems and their role in the regional and global C cycle. Therefore, organic matter quality should be considered in future models and studies with respect to C cycling.

This study concerns a new probabilistic framework to evaluate road/railway bridges after an earthquake by means of analytical fragility curves and inspections on the structure. In particular, the assessment is performed on existing reinforced concrete (RC) bridges with a common structural scheme in Italy (multi-span simply supported girder bridges). The framework is set up of 6 steps and each step is investigated. Steps 1 and 2 are a sort of preliminary work before the seismic event occurs: the creation of a database to collect all information about bridges in specific road/railway networks (step 1) and the generation of fragility curves for each bridge (step 2): fragility curves are instruments describing the probability of a structure being damaged beyond a specific damage state for various levels of ground shaking. Since step 2 is a crucial step for the outcomes of the framework, a wide investigation on the generation of fragility curves is presented, considering bridges located in strategic road network points in Veneto region (North-Eastern Italy) and different numerical modellings, in order to evaluate the best seismic vulnerability assessment. Moreover, particular attention is given to retrofit interventions by means of Fiber Reinforced Polymer (FRP) and their effect on bridge seismic vulnerability reduction. The other steps concern activities to carry out after a seismic event, useful for emergency and post-emergency phases. Step 3 regards a method to decide if inspections on bridge are needed in relation to the occurred earthquake seismic intensity; if the seismic intensity measure reaches a specific threshold, step 4 suggests how to perform visual inspections on bridges, under a probabilistic point of view, and to generate the damaged bridge fragility curves. After that, the last two steps try to give useful information to Institution and owners of bridges in order to reach an optimal road/railway network management in post-earthquake phases. Step 5 concerns a quick procedure to decide whether or not allowing traffic over damaged bridges, whereas step 6 gives information about economical benefits coming from a comparison between replace costs and retrofitting costs (considering FRP retrofitting interventions) of damaged bridges. In order to clarify the framework procedure, an example for each step is developed.

The use of Constructed Wetlands (CWs) has been increasing over the last twenty years for decentralized wastewater treatment projects (e.g. rural communities, isolated houses, etc.) because of the low maintenance requirements and operational costs, efficiency in terms of organic matter, nitrogen and suspended solid removal. Nevertheless, the application of these systems in mountain areas is faced with some issues related to the specific characteristics of these areas, namely: the complex morphology with steep slopes and limited extensions of flat land, low temperatures and, in tourist contexts, population variations throughout the year. Limited availability of suitable land is a key issue for the application of a technology requiring considerable surfaces to produce effluents of good quality. Land area requirements constitute a well-known problem of CWs that is related to a lack of knowledge on the biological reactions occurring inside the bed. In fact, usually CWs are designed by considering simple first order decay models and specific surface area requirements, while the real requirements are not taken into account, leading most of the times to an overestimation of the area required. The limited knowledge on the processes and relative efficiencies of CW leads to overdesign of CW, mainly in low temperatures contexts and where there is a fluctuation on the resident population. Despite the efficiency that could be achieved through overestimation, those systems would be underutilized for a large part of the year. Ultimately, overestimated CWs consume more land than needed, eventually leading to the decision of switching to other systems. This research aims to identify approaches and configurations that may improve the applicability of CWs for wastewater treatment of mountain communities. These approaches try to overcome the cross-cutting issue of land area requirement, as well as those related to the variation of temperature and population through the year. This was done by exploring the use of respirometric techniques for the estimation of kinetic and stoichiometric reactions inside the bed and by testing, in a pilot plant, the influence of the tourist presence and low temperatures on the efficiency of innovative CW configurations. The research was developed at both the lab and the field scale. At the lab scale, two different tests were used in order to estimate the oxygen consumption in CW filter material: liquid respirometry and the off-gas technique. Liquid respirometry proved to be a reliable method when used to measure kinetic and stoichiometric parameters of the CW’s biomass. The off-gas technique was applied at the lab scale showing promising results, though further research is needed to improve the applicability of the method to CWs. Along with that, at the lab scale, a modified AUR method was applied on the CW material to quantify the nitrification rate of real systems at different temperatures and therefore to predict the removal efficiency throughout the year. At the field scale, several tests were performed in a pilot plant composed by two hybrid CWs (VSSF+HSSF). Among these: operation under continuous and discontinuous winter conditions, operation with overload during the summer (to simulate the presence of tourists) and the application of innovative configurations (Recirculated and Aerated VSSF). All these tests were designed with the purpose of dealing with the trade-off between the reduction of a CW’s land area requirement and the enhancement of its efficiency. Two innovative configurations were tested in the pilot plant: Recirculated VSSF CW and Aerated VSSF CW. Both configurations can provide saturated and unsaturated conditions, which allow the nitrification/denitrification inside the bed. During the period when experimental configurations were tested, the traditional VSSF CW was operated with an average specific surface area to 3.5 m2/PE, the Recirculated VSSF of 1.5 m2/PE and the Aerated VSSF of 1.9 m2/PE on average. The results showed that the CW’s surface can be considerably reduced without a significant reduction in the removal efficiency. The extra investment needed to equip VSSF CWs with aeration/recirculation would be compensated by a lower area requirement. This study explored some of the problems associated with the application of traditional CWs under the physical and social conditions that characterize mountain contexts, providing important information for future research and application. First of all, a reliable tool, the respirometric technique, was explored for the estimation of kinetic and stoichiometric parameters that will allow a more precise estimation of the land area required for these systems. Moreover, two innovative configurations (the use of recirculation and aeration in CWs) were proposed to be used where traditional configurations, though well designed, are still too large to be applied. Such configurations can also be used as a temporary solution to increase the treatment capacity during tourist peak seasons, while a traditional configuration is kept over the rest of the year. While this research focused on mountain environments, the configurations and results contained therein could be applied to a wide variety of settings where shortage of land or difficult climate conditions would exclude CWs from the list of wastewater treatment options available.

The Eshelbian force is the main concept of a celebrated theoretical framework associated with the motion of dislocations and, more in general, defects in solid. Similarly, it is proven that a force driving the configuration of an elastic structure is generated through the motion and release mechanism of flexural and torsional energy. This configurational force, analytically derived through different approaches and experimentally validated, provides counterintuitive but crucial effects in elasticity. In particular, it affects equilibrium paths in systems with variable length and instabilities, bifurcation and restabilization occurring in a structure penetrating in a movable constraint. Furthermore, this configurational force (called 'Eshelby-like' in analogy to continuum mechanics) opens a totally new perspective in the mechanics of deformable mechanisms, with possible broad applications in new weighing devices (the 'elastica arm scale'), torsional locomotion along perfectly smooth channel and configurational actuators, capable of transforming torque into propulsive force.

Headwaters in Alpine regions represent the large majority of streams in natural or nearly natural conditions, which provide essential ecosystem services. These catchments are particularly sensitive to temperature changes and may suer significant changes because of climate variations. Thus, identifying the main mechanisms controlling streamflow generation and understanding the nature and variability of streamflow in Alpine streams, represent a very important contribution towards a better understanding of these complex systems. Among the multiplicity of streamflow sources (e.g., rain, snow-melt, ice-melt and groundwater), in particular snow and ice-melt play a fundamental role on the hydrological cycle of Alpine catchments and strongly affect streamflow regime. Despite several research efforts over the past decades focused on understanding the complex dynamics of the hydrological processes that characterize these environments, there is still much to disclose. Hence, the interpretation of streamflow sources can become very difficult with water discharge as the sole observed variable. The previous calls for the use of alternative data sources and methods for data analysis and visualization. This doctoral thesis aimed to contribute with new insights into the multifaceted aspects of streamflow generation in Alpine river catchments, exploring the different roles played by hydrological and geochemical information and the use of several techniques, such us tracer-based analysis, continuous wavelet transform, wavelet coherence, cross-correlation and Hovmöller diagrams; in order to investigate the mechanisms controlling streamflow generation on real case studies at different temporal scales. Hence, the present thesis is based on four main elements. In the first part of this work we show how tracer data (i.e., electrical conductivity and stable isotopes of stream water) can be used to separate the contribution of pre-event and event waters applying a two-component mixing analysis on four single rainfall events identied in the Vermigliana catchment, North-Eastern Italian Alps. The separation of streamflow into two different components allowed us to improve the conceptual model of the catchment introducing constraints that are impossible to envision counting only on streamflow measurements. Moreover, we show that the relative contribution of event water with respect to pre-event water does not change only according to the magnitude of the precipitation event and on the variations in air temperature, but it also depends on the presence and thickness of the snowpack present during the event. Second, we explored the correlation between stream water electrical conductivity (EC) and water discharge (Q) using continuous records collected during two melting periods of the Vermigliana catchment. The analysis of the hysteresis relating EC and Q at the annual scale evidenced the limitations of the use of EC measurements as a proxy of Q in these type of catchments. In addition, the combined analysis of the correlation between both signals using wavelet coherence and cross-correlation, evidenced the nature of their relationship (i.e., out of phase) and the existence of relatively constant time lag between both signals. Wavelet coherence proved to be likewise useful to identify specic periods of significant changes in the dynamics controlling streamflow generation. Furthermore, the analysis of EC and Q diurnal cycles allowed us to obtain new insights related to snow-dynamics and were also used to estimate the daily contribution to streamflow from snow-melting processes. The previous contributions may support future research on the different transfer functions that characterize water and solute transport in snow and ice-melting dominated catchments. Third, the need to understand how short and long-term climate variations may influence streamflow variability in Alpine environments lead us to the use of alternative techniques to analyse traditional long-term hydrological time series, i.e., precipitation (P), temperature (T) and streamflow (Q). We compared streamflow variability and explored the relationship between atmospheric forcing and streamflow of two case studies: Vermigliana and Sarca di Genova catchments, both located in the same region and presenting similar features, like the presence of glaciers in their upper part. Hovm öller diagrams and continuous wavelet transform were used to investigate daily and seasonal climate influences on streamflow variability, while wavelet coherence analysis was used to explore the periods on which two time series experienced oscillations at a similar frequency. Moreover, the use of these alternative techniques for data analysis and visualization, provided further insights into the hydrological response and sensitivity of the systems under study to climate changes, leading to the improvement of current conceptual models and allowing us to define a suitable framework for modelling applications, as foreseen within the following research element. The fourth element of this thesis, includes the application of an existing stochastic analytical modelling framework to the two case studies mentioned above, with the aim of characterizing and predicting streamflow distribution in these glacierized catchments. Results evidence that the size of glacier coverage on these type of catchments represents a very important feature of the system that needs to be taken account for, in fact, glaciers store a large amount of water as snow and ice, which can be rapidly released affecting signicantly the magnitude and distribution of streamflow. Overall, the results obtained during this thesis provide new insights into the multi-faceted aspects of streamflow generation in snow and glacier dominated catchments, where geochemical data as an addition to hydrological information on real case studies played an essential role. Likewise, the application of different techniques for data analysis and visualization considering a variability of temporal scales provided valuable information about the sensitivity of Alpine systems to climate changes, which may serve as a support for water resources management in these important environments. Moreover, testing the applicability of an stochastic analytical approach to this complex context allowed us to understand the influence of the presence and size of glaciers on streamflow variability. Thus, the outcomes of this study may contribute to the improvement and development of new modelling structures.

Ecosystem Services (ESs) are the goods and services supplied by ecosystems. In order to fully understand their contribution to human wellbeing, there is a need to identify them, assess their supply, recognise areas where they appear together repeatedly and analyse the interactions that may exist among them. Most of these tasks are also specifically required by the European Biodiversity Strategy for 2020, which asks Member States, by 2014, to identify key ESs and to spatially assess their supply and demand (European Commission, 2011). Nevertheless, these are difficult tasks and to date they have been only partly performed: existing studies in fact have typically focused on a small sub-set of ESs and made use of information that poorly reflects the actual variability of the ESs distribution across a region. The present research aims to fill these gaps, by developing methods involving a wide set of ESs and providing a detailed ESs assessment, based on spatial and statistical analyses. The methods have been tested on an Alpine region of Italy, Trentino. The Alps present a heterogeneous landscape, resulting from the combination of natural and urbanized environments, that allows the supply of a wide range of ESs. The research has four specific objectives. The first objective focuses on the selection and the representation over specific spatial units of the real supply of multiple ESs. Operatively, 51 experts from the local administrative offices and research institutes have been involved in the selection of the most important ESs and spatial indicators for the case study. The experts identified 25 ESs and 57 representative spatial indicators (1 to 5 indicators for each service), and provided data for indicators mapping. To consider the heterogeneity of the ESs supply across the region, indicators were mapped over 20 different spatial units, including: land cover classes, cadastral parcels, fishing zones and catchments.The second objective is to develop and test a statistical method for identifying key indicators that are spatially-explicit and able to measure the biophysical, socio-cultural and economic values of ESs (both in terms of stock and flow). Spearman pairwise correlation analysis was performed among the indicators of the same service in order to identify the highly correlated ones, hence deemed to provide redundant information. Key indicators were selected among the lowly correlated ones. 35 indicators were selected for the case study (out of the 57 initial indicators). The analysis showed that there is a minimum number of key indicators for each ES. Accordingly, three general rules were identified for the selection: (i) if the supply of an ES is regulated, both its biophysical-stock and biophysical-flow indicators must be selected, (ii) if multiple stock (flow) biophysical indicators for a single ES are mapped over different spatial units, all stock (flow) indicators must be maintained, (iii) socio-cultural or economic indicators are always selected as key indicators. The third objective is to develop and test a statistical method for defining bundles of ESs, as sets of spatially correlated services. Principal Component Analysis was used to summarize the information of the 35 indicators, while hierarchical clustering was applied to identify 11 ESs clusters. Clusters were turned into bundles by analyzing the spatial variability of the services due to biophysical (e.g. morphological conditions) and human (e.g. land use) factors. The results of the analysis show that in Trentino multiple ESs can be grouped in a few number of bundles with a complex shape. In particular, areas with poor ESs supply are grouped in one single bundle and the largest bundle follows the spatial distribution of a single land cover class: i.e. forest.The fourth objective is to develop a method to study interactions among ESs, by combining statistical and spatial analyses. In fact, the supply of a given ES is correlated with the supply of other ESs and it is affected by multiple external factors. Correlations may be positive when an increase in the supply of one service corresponds to higher supplies of other services (i.e. synergies), or negative when an increase in the supply of one service corresponds to lower supplies of other services (i.e. tradeoffs). The degree of interactions among 35 key indicators is determined by performing a Spearman pairwise correlation analysis. The latter enabled to identify six patterns of ESs interactions, one pattern of tradeoffs and five of synergies. The analysis showed that the local land use management has not compromised the capacity of ecosystems to provide regulating services while supplying the provisioning ones. The external factors causing the variability of the services across the region were identified and explained by means of spatial and Spearman correlation analyses among the ESs principal components. Principal components were turned into drivers of change by analyzing the spatial variability of the ESs due to biophysical (e.g. forest density) and human (e.g. land use) factors. Land use management was found as the external factor that causes the greatest variability of the ESs distribution across the region. Within forest areas, forest management activities that involve loss of vegetation were found as the main drivers of ESs change. This research aimed to consider a wide set of ESs and information able to reflect the actual variability of the services distribution across a region. It proposed a scientifically sound methodology to deal with the main issues of the ESs spatial assessment, that may reveal efficiently applicable in other geographical areas where ESs are heterogeneously supplied.

Biological nitrogen removal from strong ammonium wastewaters received a great deal of attention during the last years. Since the discovery of anammox bacteria the traditional theory of biological nitrogen removal has been extended to new nitrogen metabolic pathways. This thesis deals with the study of Simultaneous partial Nitritation, Anammox and Denitrification (SNAD) process in a Sequencing Batch Reactor (SBR) to treat wastewaters with a high ammonium load and low biodegradable organic matter, such as anaerobic digester effluent and old landfill leachate. The bacterial diversity in the reactor was investigated by analysis of specific gene clone libraries, Polymerase Chain Reaction (PCR) and fluorescence in situ hybridization (FISH). SNAD process is a complex biological process where different populations with opposed environmental requirements coexist, thus, experiments have been performed with a lab – scale reactor, focusing on the assessment of the feasibility of SBR configuration for achieving a simultaneous carbon and nitrogen removal. In addition, proper operational conditions, control strategies and a suitable loads were investigated.

In the last decades the need for an effective seismic protection and vulnerability reduction of strategic structures and particularly the architectural heritage determined a growing interest in Structural Health Monitoring (SHM) as a measure of passive mitigation of earthquake effects. The object of monitoring is to identify, locate and classify type and severity of damages induced by external actions or degradation phenomena and to assess their effects on the structural performance. In this way it is possible to take appropriate measures to reduce the danger of collapse and, when necessary, perform strengthening interventions to improve the structural and seismic capacity. Motivated by the above reasons, this thesis aims at providing a contribution to the development of techniques and integrated methodologies, based on SHM, for the assessment and protection of Cultural Heritage (CH) buildings and monuments. Firstly, after a detailed state of the art review on specific topics related to SHM of civil engineering structures, a new methodology for the implementation of monitoring techniques on historic masonry structures is proposed. Selected case studies, equipped with distributed sensors and acquisition systems, allowed the definition and successive validation of SHM as a knowledge-based assessment tool, implemented to evaluate intervention needs, following an incremental approach during their execution, and to control the damage states of buildings in a post-seismic scenario. In order to maximize the benefits of SHM and optimize the entire process, dedicated software for static monitoring and automated algorithms for modal parameters identification have been developed, able to provide almost real time information on the health state of the monitored structure. Finally integrated procedures based on robust statistical and numerical models have been implemented to interpret and exploit SHM outputs to assess the structural conditions of the investigated CH buildings.

Finite plane strain bending is solved for a multilayered elastic–incompressible thick plate. This multilayered solution, previously considered only in the case of homogeneity, is in itself interesting and reveals complex stress states such as the existence of more than one neutral axis for certain geometries. The bending solution is employed to investigate possible in-plane and out-of-plane incremental bifurcations. The analysis reveals that a multilayered structure can behave in a completely different way from the corresponding homogeneous plate. For a thick plate of neo-Hookean material for instance, the presence of a stiff coating strongly affects the bifurcation critical angle. Experiments designed and performed to substantiate our theoretical findings demonstrate that the theory can be effectively used as a design tool for predicting the capability of an elastic multilayered structure.